Micro ch 38: STI, Micro 2 Test 1, Micro Ch 37: UTI, Quizzes 1-4 micro 2, Bacteremia and Sepsis Chapter 36, CNS Chapter 35, GI Infections, Micro: Soft Tissues, Chapter 33: Skin and Soft Tissue Infections, CHapter 32: Upper repiratory Micro, Antibiotic...

The following characteristics of an obligate anaerobic gram-negative bacilli best describe which of the listed genera? Gram staining = Long, slender rods with pointed ends Colonial appearance = Dry bread crumbs or "fried-egg" appearance Penicillin two-unit disk test = Susceptible A. Bacteroides spp. B. Fusobacterium spp. C. Prevotella spp. D. Porphyromonas spp.

ANS: B

The most common bacterium found on the skin is: A. Coagulase-negative streptococci B. Coagulase-negative staphylococci C. Escherichia coli D. Pseudomonas aeruginosa

ANS: B

Vibrio vulnificus is responsible for causing which of the following conditions: A. Gangrene B. Necrotizing cellulitis and sepsis C. Meningococcemia D. Disseminated intravscular coagulation

ANS: B

What is the most common cause of community-acquired pneumonia in adults? A. Influenza virus B. Streptococcus pneumoniae C. Staphylococcus aureus D. Legionella pneumophila

ANS: B

Which of the following methods describes the mechanism that some bacteria possess that expels the antimicrobial agent from the cell before it reaches its target? A. enzyme degradation/hydolysis B. efflux pump elimination C. modification of antibiotic target D. reduced permeability of the antibiotic

ANS: B

28. -Lactamases hydrolyze -lactam antibiotics using two distinct mechanisms: those having a metallo-based mechanism of action and those with a. ring-specific enzymes. b. a serine-based mechanism of action. c. a chromosomal mechanism of action. d. a transporter mechanism of action.

ANS: B -Lactamases hydrolyze -lactam antibiotics using two distinct mechanisms: those having a metalol-based mechanism of action and those having a serine-based mechanism of action. OBJ: Level 1: Recall

5. Which of these is an abscess that extends more deeply into the subcutaneous fat and may have multiple draining sites? a. Furuncle b. Carbuncle c. Folliculitis d. Impetigo

ANS: B A carbuncle is an abscess that extends even more deeply into the subcutaneous fat and may have multiple draining sites. Staphylococcus aureus is the most common causative pathogen. REF: page 814 OBJ: Level 1 - Recall

27. All of the following viruses cause a characteristic viral syndrome and severe bleeding manifestations EXCEPT: a. Ebola b. Rabies c. Junin d. Marburg

ANS: B A number of viruses of the Togaviridae (e.g., yellow fever and dengue virus), Arenaviridae (e.g., Junin and Machupo viruses), and Bunyaviridae (e.g., Hantavirus) families, as well as several ungrouped viruses (e.g., Ebola, Marburg, and Lassa fever viruses), may cause a characteristic viral syndrome (fever, headache, myalgias, nausea vomiting, abdominal pain, prostration) accompanied by severe bleeding manifestations (e.g., gastrointestinal bleeding, hematuria). REF: page 827 OBJ: Level 1 - Recall

Purpura fulminans, a skin manifestation of disseminated intravascular coagulation, is associated with which condition? A. Hepatitis B. Meningococcemia C. Encephalitis D. Salmonella

ANS: B A skin manifestation of disseminated intravascular coagulation is purpura fulminans. This syndrome has classically been associated with meningococcemia, but bloodstream infections with S. aureus, Streptococcus pneumoniae, and Haemophilus influenzae have also been linked to this condition. It is characterized by rapidly developing skin hemorrhage and necrosis, and peripheral gangrene accompanied by shock syndrome.

2. All of the following organisms commonly cause meningitis EXCEPT: a. Streptococcus pneumoniae b. Pseudomonas aeruginosa c. Haemophilus influenzae d. Neisseria meningitidis

ANS: B Acute meningitis is commonly caused by bacteria (e.g., S. pneumoniae, N. meningitidis, H. influenzae), or viruses (e.g., enteroviruses, herpes virus, mumps virus). REF: page 856 OBJ: Level 1 - Recall

6. Which of the immunocompromised circumstances listed here is a form of functional immunodeficiency? a. Sex b. Age c. Chronic illness d. Pregnancy

ANS: B Age is a form of functional immunodeficiency. Infants and the elderly are more susceptible to certain respiratory tract infections and are more likely to develop complications of these infections. REF: page 776 OBJ: Level 1 - Recall

8. Which of the following is characteristic of members of the genus Clostridium? a. Catalase positive b. Spore-forming anaerobic bacilli c. Spore-forming anaerobic cocci d. Facultative anaerobes

ANS: B All spore-forming anaerobic bacilli are classified in the genus Clostridium and collectively referred to as clostridia. OBJ: Level 1: Recall

2. What characteristic of urine inhibits growth of many pathogens? a. High glucose level b. Low pH c. High protein level d. High pH

ANS: B Although urine is frequently considered a good culture medium, the extremely high urine osmolarity (concentration) and low pH levels inhibit the growth of many uropathogens and almost all normal bacterial florae of the urethra. REF: page 887 OBJ: Level 1 - Recall

18. What is the most common cause of bacterial gastroenteritis in the world? a. Salmonella typhi b. Campylobacter jejuni c. Shigella sonnei d. Yersinia enterocolitica

ANS: B Although various Campylobacter spp. have been isolated as a cause of diarrhea, C. jejuni is the most common bacterial cause of gastroenteritis in the world. REF: page 842 OBJ: Level 1 - Recall

2. What is an anaerobe? a. An organism that can live with very little oxygen b. An organism that does not require oxygen to live c. An organism that requires some oxygen but moderate concentrations of CO2 to live d. An organism that requires small amounts of oxygen and carbon dioxide to live

ANS: B Anaerobes are organisms that do not require oxygen for life and reproduction. OBJ: Level 1: Recall

31. What do specimens with multiple uropathogens (i.e., three or more) indicate? a. Probable contamination b. Polymicrobial infection c. Bacteremia d. Septicemia

ANS: A Guidelines in Table 37-9 from the text, suggest the following, remembering that cost-effective strategies may define different algorithms for inpatient and outpatient cases: specimens with multiple uropathogens (i.e. three or more) indicate probably contamination; one or two significant uropathogens present should be routinely identified, and one or two uropathogens in small numbers should be routinely identified if the clinical situation warrants, such as in acute urethral syndrome or cases of previous antibiotic therapy. REF: page 900 OBJ: Level 1 - Recall

20. What organism causes epiglottis? a. Haemophilus influenzae b. Streptococcus pneumoniae c. Moraxella catarrhalis d. Bordetella pertussis

ANS: A H. influenzae type b is uniquely associated with epiglottis. REF: page 783 OBJ: Level 1 - Recall

1. Relatively nontoxic antimicrobial therapeutic agents include all of the following, except a. heavy metals. b. antibiotics. c. preservatives. d. antiseptics.

ANS: A Heavy metals, although they have antimicrobial properties, are highly toxic to patients. Antimicrobial agents include antiseptics, antibiotics, preservatives, sterilants, and disinfectants; all have the capacity to kill or suppress the growth of microorganisms. OBJ: Level 1: Recall

8. What immunosuppressive agents increase a patient's risk of bacteremia? a. Steroids and chemotherapy drugs b. Steroids and cytotoxic drugs c. Chemotherapy drugs and cytotoxic drugs d. All of the above

ANS: A Immunosuppressive agents, especially steroids and anticancer chemotherapeutics, place patients at increased risk for bacteremia. REF: page 872 OBJ: Level 1 -

Question 24 In which type resistance is the antibiotic actively pumped out of the bacterial cell, such that sufficient levels cannot be attained? A. Efflux B. Modification of target site C. Enzyme inactivation D. Restrictive enzyme channels

ANS: A

Question 25 Of the following specimens, which should be rejected for anaerobic work-up? A. Sputum B. Cerebrospinal fluid C. Abdominal abscess D. Abdominal abscess

ANS: A

Question 30 The Gram stain of an expectorated sputum shows 25-30 PMNs/HPF and 0-4 Squamous Epithelial Cells/HPF and a moderate amount of gram-positive cocci in clusters. This indicates: A. an acceptable specimen and an infectious state. B. normal flora of the lower respiratory tract. C. contamination and an unacceptable specimen. D. None of these is correct.

ANS: A

Question 31 Throat cultures are most often performed to diagnose infection by __________ A. Streptococcus pyogenes B. Streptococcus pneumoniae C. Streptococcus agalactiae D. Staphylococcus aureus

ANS: A

Question 5 What organism is the predominate cause of epiglottis? A. Haemophilus influenzae B. Streptococcus pneumoniae C. Moraxella catarrhalis D. Bordetella pertussis

ANS: A

Question 6 Which of the following pairs of organisms grow on kanamycin, vancomycin, laked blood agar? A. Bacteroides and Prevotella B. Mobiluncus and Gardnerella C. Porphyromonas and Enterococcus D. Veillonella and Capnocytophaga

ANS: A

Question 7 A CSF was collected from a lumbar puncture to evaluate for possible meningitis. Four tubes were collected and sent to the microbiology laboratory for analysis. Which of the four tubes is preferred for microbiology studies? A. 2 B. 1 C. 3 D. 4

ANS: A

Question 7 Acceptable specimen sources for culture of anaerobic bacteria includes: A. abscess B. stool C. clean catch urine D. vaginal

ANS: A

Question 9 A strict anaerobe that produces terminal spores is: A. Clostridium tetani B. Corynebacterium diphthereria C. Bacillus anthracis D. Propionibacterium acnes

ANS: A

Which drug crosses the blood brain barrier and poses a hematopoietic toxicity risk for aplastic anemia? A. chlroamphenicol B. doxycline C. Gentamicin D. imipenem

ANS: A

27. The -lactam agents consist of all the following antibiotics, except a. vancomycin. b. penicillins. c. cephalosporins. d. carbapenems.

ANS: A -Lactam antibiotics are the most common treatment for bacterial infections and consist of four major groups: penicillins, cephalosporins, monobactams, and carbapenems. OBJ: Level 1: Recall

31. An anaerobic culture reveals colonies with a double zone of hemolysis on SBA plate. There was no growth on plates incubated aerobically. The Gram stain of that organism was a boxcar-shaped, gram-positive bacillus. What organism is this? a. Clostridium perfringens b. C. difficile c. C. ramosum d. C. clostridioiforme

ANS: A A boxcar-shaped, anaerobic, gram-positive bacillus that produces a characteristic double zone of hemolysis on blood agar can be presumptively identified as C. perfringens. OBJ: Level 3: Synthesis

1. What part of the urinary tract is most susceptible to infection? a. Urethral mucosa b. Bladder c. Ureters d. Nephrons

ANS: A Except for the urethral mucosa and the renal medulla, which appear to be relatively susceptible to infection, the normal urinary tract is resistant to colonization and subsequent infection by bacteria. REF: page 886 OBJ: Level 1 - Recall

6. All of the following factors are associated with an unfavorable outcome in bacteremia EXCEPT: a. Pneumonia b. Polymicrobial bacteremia c. Presence of malignancy d. AIDS

ANS: A Factors associated with an unfavorable outcome in bacteremia include age older than 70 years; polymicrobial bacteremia; presence of malignancy; AIDS or renal failure; origin of the bacteremia in the respiratory tract, bowel; unknown origin; and inappropriate antimicrobial therapy. REF: page 872 OBJ: Level 1 -

10. Immunization has decreased which major cause of bacteremia in children? a. Haemophilus influenzae b. Streptococcus pneumoniae c. Escherichia coli d. Hepatitis A

ANS: A Finally, some organisms have become less prevalent causes of bacteremia because of immunization practices that have decreased the risk of infection with such pathogens. For example, infection with H. influenzae b, formerly a major cause of bacteremia and sepsis in children, decreased by over 95% after introduction of the conjugate Hib vaccine. REF: page 873 OBJ: Level 1 -

9. When a patient has an indwelling urinary catheter, what symptoms may be present? a. Flank pain and fever b. Urgency and dysuria c. Frequency and flank pain d. Costovertebral angle tenderness and fever

ANS: A Flank pain and fever without lower urinary tract symptoms, and bacteremia without any urinary tract symptoms, can be seen in patients with indwelling urinary catheters. REF: page 889 OBJ: Level 1 - Recall

26. A cerebrospinal fluid (CSF) sample collected from a child yields the following results: turbid andcloudy, very high total protein levels, and very low glucose levels. What would the probable diagnosis be? a. Bacterial meningitis b. Aseptic meningitis c. Encephalitis d. Brain abscess

ANS: A In acute bacterial meningitis, the CSF is turbid or cloudy because protein levels are significantly raised. Glucose levels are very low (less than 40% of serum glucose concentration) in most patients with bacterial meningitis. REF: page 866 OBJ: Level 3 - Synthesis

35. A patient undergoes a colon resection. Because of the amount of bacteria present in the colon, the physician put the patient on broad-spectrum antibiotics after surgery. The patient develops a fever 2 days after surgery. He developed an infection with vancomycin-resistant enterococci (VRE). What antibiotics can be used to treat this organism? a. Synercid b. Quinolones c. Aminoglycosides d. Erythromycin

ANS: A In an attempt to avoid the overuse and subsequent emergence of resistance to vancomycin, vancomycin was used sparingly during its introduction. Unfortunately, this strategy did not prevent overuse and resulted in the emergence of vancomycin-resistant enterococci (VRE) isolates in health care settings. Currently, there are two choices for the treatment of VRE: Synercid or Linezolid. OBJ: Level 1: Recall

16. Bacterial vaginosis is a synergistic infectious process involving all the following bacteria, except a. Eubacterium. b. Bacteroides. c. Gardnerella. d. Peptostreptococcus.

ANS: A In bacterial vaginosis, a shift in the vaginal biota occurs resulting in a decrease in lactobacilli. This is accompanied by the overgrowth of other endogenous anaerobes of the vagina such as Mobiluncus spp., Bacteroides spp., Prevotella spp., anaerobic gram-positive cocci, and the aerobic bacterium Gardnerella vaginalis. OBJ: Level 1: Recall

1. What is the volume of cerebrospinal fluid (CSF) in an adult human? a. 90 to 150 mL b. 15 to 45 mL c. 40 to 80 mL d. 200 to 300 mL

ANS: A In normal adults, the CSF volume ranges from 90 to 150 mL, the protein level is 15 to 45 mg/dL, and the CSF glucose level is 40 to 80 mg/dL (CSF glucose:serum glucose ration of 0.6). REF: page 856 OBJ: Level 1 - Recall

1. What makes cervicitis difficult to diagnose? a. Lack of well-recognized symptoms b. Inability to culture causative agents c. Most causes are non-infectious d. Symptoms are obvious - not difficult to diagnose

ANS: A It is considered to be the silent partner of male urethritis because symptoms are not always obvious. The lack of well-recognized symptoms and signs of cervicitis make its diagnosis very difficult. REF: page 908 OBJ: Level 2 - Interpretation

10. What is the infective particle of Chlamydia? a. Elementary body b. Initial body c. Negri body d. Entire Chlamydia organism

ANS: A The infective particle is the elementary body, which is the metabolically inert form of the organism. REF: page 907 OBJ: Level 1 - Recall

Question 4 What organisms are most frequently isolated frequently isolated from cultures of individuals with otitis media? A. Staphylococcus aureus and Escherichia coli B. Streptococcus pneumoniae and Haemophilus influenzae C. S. pneumoniae and Mycoplasma pneumoniae D. H. influenzae and Neisseria meningitidis

ANS: B

Question 5 The presence of yellow colonies on thiosulfate-citrate-bile salt-sucrose medium is suggestive of A. Aeromonas hydrophila B. Vibrio cholerae. C. Yersinia enterocolitica. D. Shigella sp.

ANS: B

Question 6 Which of the following is most likely present in a complete blood count of a person with strongyloidiasis? A. Macrocytosis B. Eosinophilia C. Thrombocytopenia D. Microcytosis

ANS: B

Question 8 What is empyema? A. A collection of fluid in the lung resulting from the pathogenesis of bacterial pathogens B. A collection of fluid in the lung resulting from the pathogenesis of viral pathogens C. A collection of purulent fluid in the pleural space between the lung and the chest wall D. A collection of purulent fluid in the bronchi and alveoli

ANS: B

Question 9 What organism is the most common opportunistic pathogen that routinely infects patients with HIV/AIDS? A. Mycoplasma pneumoniae B. Pneumocystis jirovecii C. Serratia marcescens D. Respiratory syncytial virus

ANS: B

Question 9 What type of diarrheal illness has no fever and no blood or pus in the stool? A. Diarrhea where the mucosal surface is invaded B. Diarrhea caused by enterotoxins C. Diarrhea caused by endotoxins D. Diarrhea where the full bowel thickness is invaded

ANS: B

2. Antibiotics work by targeting all of the following, except a. DNA replication. b. bacterial plasmid DNA. c. bacterial cell wall. d. RNA transcription.

ANS: B Antibiotics target the bacterial cell wall and the cellular machinery responsible for the synthesis of precursor molecules; cellular targets include DNA replication, RNA transcription, and mRNA translation. Although numerous antibiotic classes exist with different modes of action, bacteria evolved and adopted numerous strategies to counteract the action of antibiotics. OBJ: Level 1: Recall

15. What group has more urinary tract infections (UTIs) caused by Staphylococcus saprophyticus? a. Asymptomatic elderly men b. Symptomatic sexually active young women c. Symptomatic middle-age men d. Elderly women

ANS: B S. saprophyticus is found predominantly in symptomatic sexually active women younger than age 40. REF: page 891 OBJ: Level 1 - Recall

29. What intestinal parasite is able to leave the intestines and cause metastatic diseases, especially liver abscesses? a. Giardia lamblia b. Entamoeba histolytica c. Cryptosporidium parvum d. Microsporidia

ANS: B The trophozoites of E. histolytica are able to leave the intestine and can cause metastatic illness, most frequently as a liver abscess. REF: page 846 OBJ: Level 1 - Recall

2. Although Neisseria gonorrhea usually grows in the cervix and male urethra, all the following sites can support growth EXCEPT: a. Mouth b. Ears c. Eyes d. Anus

ANS: B These bacteria can grow and multiply easily in the reproductive tract of women, including the cervix, uterus, and fallopian tubes, and in the urethra of both men and women. The bacterium can also grow in other areas of the body to include the mouth, throat, eyes, and anus depending on the exposure. REF: page 906 OBJ: Level 1 - Recall

41. Transposons are a. circular structures present in bacteria that contain genes encoding proteins and RNA, and have the capacity to self-replicate and portion into daughter cells during cellular division. b. DNA elements that encode transposition and excision function and can transpose from one place on the chromosome to another. c. genetic elements capable of integrating resistance genes (cassettes) by an integron-encoded, site-specific recombinase. d. DNA elements found in bacteria that carry genes only for the enzymes needed to promote their own transposition.

ANS: B Transposons (Tn) are DNA elements that encode transposition and excision functions and can transpose from one place on the chromosome or plasmid to another. Transposase, an enzyme that facilitates nonhomologous recombination, mediates the transposition event. Transposons are also capable of carrying antibiotic resistance genes and function as shuttles, carrying these determinants among plasmids and between plasmids and chromosomal DNA. OBJ: Level 1: Recall

18. What is the most common localized infection of the upper respiratory tract in preschool-age patients? a. Orbital cellulitis b. Acute sinusitis c. Otitis media d. Mastoiditis

ANS: C Otitis media is the most common localized infection of the upper respiratory tract in pre-school- age patients. One study showed that almost a third of all visits by preschool children to pediatricians involved diseases of the middle ear. REF: page 782 OBJ: Level 1 - Recall

25. Biofilms are groups of bacteria that are irreversibly attached to surfaces and are embedded in a matrix of extracellular polymeric substances. They are most commonly found on a. native heart valves. b. dialysis shunts. c. indwelling medical devices. d. patient beds.

ANS: C Bacterial biofilms are prevalent in the clinical setting, and found on numerous environmental surfaces and indwelling medical devices. OBJ: Level 2: Interpretation

7. All the following organisms are found in the GI tract, except a. Bacteroides. b. Clostridium. c. Propionibacterium. d. Bifidobacterium.

ANS: C Bacteroides vulgatus, B. thetaiotaomicron, and B. distasonis are among the most common species of bacteria isolated from human feces. Other species commonly inhabiting the GI tract include Bifidobacterium, Clostridium, Eubacterium, and Peptostreptococcus. Propionibacterium spp. are frequently associated with the skin. OBJ: Level 1: Recall

28. What does infection with influenza predispose patients to? a. Secondary otitis media b. Secondary sinusitis c. Secondary pharyngitis d. Secondary bacterial pneumonia

ANS: D During the winter season, the elderly and patients with underlying heart and lung disease, diabetes, renal disease, or immunosuppression are at increased risk for developing primary influenza pneumonia. Additionally, influenza infection predisposes patients to developing a secondary bacterial pneumonia. REF: page 788 OBJ: Level 1 - Recall

25. Diagnosis of central nervous system (CNS) infections is based on: a. Neurologic symptoms b. Physical symptoms c. History d. Cerebrospinal fluid (CSF) laboratory examination

ANS: D The diagnosis of CNS infections is based on examination of CSF samples obtained by lumbar puncture. REF: page 865 OBJ: Level 1 - Recall

20. What is the environmental reservoir of Campylobacter? a. Lakes and rivers b. Fish c. Arthropod vector d. Wild and domestic animals

ANS: D The environmental reservoir of Campylobacter includes both wild and domestic animals, most frequently birds. This is usually a food-borne infection, often with poultry as the source. REF: page 842 OBJ: Level 1 - Recall

30. On egg-yolk agar, Clostridium perfringens will demonstrate: a. brown to black colonies with a halo b. bluish-green sheen on surface of colonies c. off-white precipitate around colonies d. All of the above

ANS: C Egg-yolk agar detects the presence of lecithinase by the formation of an off-white precipitate around the colonies. C. perfringens is lecithinase positive. The presence of a bluish-green sheen ("mother of pearl") on colonies grown of this medium indicates lipase activity. C. perfringens is negative for lipase. OBJ: Level 2: Interpretation

Question 12 Sodium polyanetholsulfonate (SPS) performs all the following functions in the blood culture bottles, except A. anticoagulation. B. prevention of phagocytosis. C. act as a bacterial nutrient. D. inactivate certain antimicrobials.

ANS: C SPS, a commonly used additive in blood culture media, performs the following functions: anticoagulation, neutralization of the bactericidal effect of human serum, prevention of phagocytosis, and inactivation of certain antimicrobial agents.

27. SPS performs all the following functions in the blood culture bottles EXCEPT: a. Anticoagulation b. Prevention of phagocytosis c. Act as a bacterial nutrient d. Inactivate certain antibiotics`

ANS: C SPS, one of the commonly used additives, performs the following functions: anticoagulation, neutralization of the bactericidal effect of human serum, prevention of phagocytosis, and inactivation of certain antimicrobial agents. REF: page 878 OBJ: Level 2 - Interpretation

Question 28 A gram negative pleomorphic bacillus that produced black colonies on Bacteroides Bile Esculin agar and was positive for catalase and negative for lipase, lecithinase, and indole is most likely: A. Clostridium perfringens B. Fusobacterium necrophorum C. Prevotella intermedia D. Bacteroides fragilis

ANS: D

Question 29 Culture of the anterior nares may be performed to: A. determine if Bordetella pertussis is present. B. identify infection by Streptococcus pyogenes. C. determine if Haemophilus influenzae is present. D. identify Staphylococcus aureus carriers.

ANS: D

Question 3 What type of diarrheal illness has a rapid onset of symptoms after food ingestion (usually <12 hours)? A. Diarrhea where the mucosal surface is invaded B. Diarrhea where the full bowel thickness is invaded C. Diarrhea caused by endotoxins D. Diarrhea caused by enterotoxins

ANS: D

Question 34 A group of swim team members breaks out in a rash (folliculitis) the day after swimming at the pool. What organism is probably responsible for this outbreak? A. Staphylococcus aureus B. Enterococcus sp. C. Escherichia coli D. Pseudomonas aeruginosa

ANS: D

Question 37 Which one of the following statements about Campylobacter jejuni is false? A. It is a curved gram-negative rod B. It is associated with neutrophils in the stool C. It can occur in domestic animals, raw milk and undercooked poultry D. It does not require special incubation conditions to grow in culture

ANS: D

Question 38 The selective medium XLD is seen in this image. What is the significance of the black colonies observed on this plate? XLD Agar | Xylose-lysine-deoxycholate agar A. Lactose fermentation B. No lactose fermentation C. Sucrose fermentation D. Hydrogen sulfide production

ANS: D

Question 5 A CSF sample collected from a child yields the following results: turbid, very high total protein levels, and very low glucose levels. What would the probable diagnosis be? LO8; Level 3 A. Encephalitis B. Brain abscess C. Aseptic meningitis D. Bacterial meningitis

ANS: D

Question 7 1 / 1 pts Patients with influenza virus infection are predisposed to A. secondary otitis media B. secondary sinusitis. C. secondary pharyngitis. D. secondary bacterial pneumonia.

ANS: D

Question 7 Which of the following have a "running" or "wet-looking" colony morphology on growth media? A. Salmonella B. Shigella C. Yersinia enterocolitica D. Campylobacter jejuni

ANS: D

Question 8 Presence of red colonies with black centers on xylose-lysine-decarboxylase medium is indicative of A. lactose fermentation and utilization of citrate. B. lactose fermentation and H2S positive. C. nonlactose fermentation and tryptophan positive. D. nonlactose fermenter and H2S positive.

ANS: D

Question 8 Propionibacterium acnes is most often associated with: A. food poisoning B. post antibiotic diarrhea C. tooth decay D. blood culture contamination

ANS: D

Streptobacillus moniliformis is the causative agent of which of the following conditions? A. Buruli ulcer B. swimmer's itch C. Tuleremia D. Rat bite fever

ANS: D

9. All of the following are -lactam antibiotics, except a. penems. b. monobactams. c. carbapenems. d. monoterpenes.

ANS: D -Lactam antibiotics, such as penems, cephems, carbapenems, and monobactams, act by binding to penicillin-binding proteins, which are bifunctional transpeptidases/transglycosylases that cross-link peptidoglycan. Without this cross-linking of the peptidoglycan, the cell walls break down. OBJ: Level 1: Recall

28. Septi-Chek is which type of blood culture system? a. Continuous-monitoring blood culture system b. Lysis centrifugations blood culture system c. Aerobic-anaerobic blood culture system d. Biphasic broth-slide system

ANS: D A broth-slide system was designed from the original biphasic blood culture medium culture bottle. Septi-Chek consists of a slide paddle containing chocolate, MacConkey, and malt extract agars attached to the top of a standard broth bottle. Once these bottles have been inoculated, they should be tipped daily or at least twice weekly so as to bathe the slide paddle with the broth culture medium. REF: page 878 OBJ: Level 1 -

9. What is required for culturing Chlamydia? a. Embryonated chicks b. Thayer-Martin, modified (MTM) media c. Martin-Lewis (ML) media d. Cell cultures

ANS: D Chlamydia trachomatis is an obligately intracellular bacterium, requiring cell cultures for in vitro culturing. REF: page 906 OBJ: Level 1 - Recall

6. What is the most common cause of travelers' diarrhea? a. Giardia lamblia b. Escherichia coli c. Entamoeba histolytica d. Clostridium difficile

ANS: B Travelers' diarrhea is most commonly caused by enteropathogenic E. coli. This illness has a short incubation period (usually less than 24 hours) and normally lasts between 1 and 3 days. If a diarrheal illness lasts longer than this or develops in the days or weeks after a traveler returns home, the patient more likely has a different pathogen. REF: page 838 OBJ: Level 1 - Recall

9. What is helpful when initiating empiric antimicrobial therapy? a. Knowing the patient's age b. Knowing the pathogens most likely to cause a particular type of infection c. Knowing a patient's medical history d. Knowing the anatomy of the respiratory tract

ANS: B When empiric antimicrobial therapy is necessary, it is important to have a working knowledge of the organisms most likely to cause the type of infection observed and of the antibiotics that are most likely to be effective.

38. Extended -lactamases target all the following antibiotics, except a. penicillins. b. cephalosporins. c. monobactams. d. macrolides.

ANS: D The extended-spectrum -lactamases (ESBLs) are now known to be derivatives of the common type -lactamases, but they differ by one or more amino acid substitutions near the reactive site of the enzyme. ESBLs have specific sets of penicillins, cephalosporins, and monobactams they can hydrolyze, and all ESBLs are not capable of hydrolyzing all cephalosporins equally well. OBJ: Level 1: Recall

4. What is the first step in developing meningitis? a. A cold that compromises your immune system b. Living in close quarters, like military barracks or a college dorm c. Poor sanitary conditions d. Nasopharyngeal colonization by a meningeal pathogen

ANS: D The first step in the development of a meningeal infection with bacteria involves nasopharyngeal colonization by one of the meningeal pathogens, followed by local invasion across the mucosal barrier and entry into the bloodstream. REF: page 857 OBJ: Level 1 - Recall

What is the first step in developing bacterial meningitis? A. A cold that compromises the immune system B. Living in close quarters, like military barracks or a college dorm C. Poor sanitary conditions D. Nasopharyngeal colonization by a meningeal pathogen

ANS: D The first step in the development of a meningeal infection with bacteria involves nasopharyngeal colonization by one of the meningeal pathogens, followed by local invasion across the mucosal barrier and entry into the bloodstream.

34. A young, healthy patient goes into the hospital for reconstructive knee surgery and spikes a fever the day after surgery. The doctor finds the patient has a nosocomial infection with methicillin-resistant Staphylococcus aureus (MRSA). What antibiotic should the doctor use to treat this patient? a. Penicillin b. Aminoglycosides c. Macrolides d. Vancomycin

ANS: D The glycopeptide vancomycin is used to treat enterococci that cause endocarditis and is the drug of choice for the treatment of MRSA. OBJ: Level 1: Recall

30. Acquired antibiotic resistance mechanisms include a. efflux mechanisms. b. acquisition of new targets. c. modification of existing antibiotic targets. d. All of the above

ANS: D This section focuses on acquired mechanisms such as efflux, modification of existing antibiotic targets, acquisition of new targets, and production of enzymes that inactivate the antibiotic. OBJ: Level 1: Recall

What do these have in common: St. Louis encephalitis virus La Cross virus WNV

Common arborviruses that cause meningitis

What do these have in common: Cryptococcus neoformans Coccidioides immitis Histoplasma capsulatum

Common fungal causes of CNS infection

Which of these is an abscess that extends more deeply into the subcutaneous tissue and may have multiple draining sites? a. Furuncle b. Folliculitis c. Impetigo d. Carbuncle

d. Carbuncle

What causes rubeola? a. Calicivirus b. Herpesvirus c. Torovirus d. Paramyxovirus

d. Paramyxovirus

Question 21 All of the following antibiotics inhibit cell wall formation, except: A. chloramphenicol. B. vancomycin. C. penicillin. D. cephalosporins.

ANS: A

Question 23 Aplastic anemia may be a serious side effect of administration of which of the following? A. Chloramphenicol B. Methicillin C. Tobramycin D. Sulfonamide

ANS: A

Question 32 What organism is the most common opportunistic pathogen that routinely infects patients with HIV/AIDS? A. Mycoplasma pneumoniae B. Pneumocystis jirovecii C. Respiratory syncytial virus D. Serratia marcescens

ANS: B

Question 39 What is the most common cause of travelers' diarrhea? A. Clostridium difficile B. Escherichia coli C. Entamoeba histolytica D. Giardia lamblia

ANS: B

10. Which spore type and location is found on Clostridium tetani? A. Round, terminal spores B. Round, subterminal spores C. Ovoid, subterminal spores D. Ovoid, terminal spores

A Spore appearance and location, along with Gramstain morphology, aids in distinguishing theClostridium spp. Round, terminal spores (drumstickspores) are demonstrated when C. tetani is grown inchopped meat with glucose broth. Recognition ofspores is particularly important because C. tetanisometimes appears as gram negative.

7. A gram-positive spore-forming bacillus growing on sheep-blood agar anaerobically produces a double zone of β-hemolysis and is positive for lecithinase.What is the presumptive identification? A. Bacteroides ureolyticus B. Bacteroides fragilis C. Clostridium perfringens D. Clostridium difficile

7. C C. perfringens produces a double zone ofβ-hemolysis on blood agar, which makesidentification relatively easy. The inner zone ofcomplete hemolysis is caused by a θ-toxin andthe outer zone of incomplete hemolysis is causedby an α-toxin (lecithinase activity). The Bacteroidesspp. are gram-negative bacilli, and C. difficile islecithinase negative and does not produce adouble zone of β-hemolysis.

What is the most significant predisposing factor to Clostridium difficile-associated disease? A. Antimicrobial therapy B. Young age C. Consumption of undercooked beef D. Travel to developing countries

A

Which test is performed in order to confirm an infection with Clostridium botulinum? A. Toxin neutralization B. Spore-forming test C. Lipase test D. Gelatin hydrolysis test

A C. botulinum and C. sporogenes have similarcharacteristics biochemically (see the following chart),and definitive identification of C. botulinum is madeby the toxin neutralization test for its neurotoxins inserum or feces. Specimens should be kept at 4°C andsent to the CDC for culture and toxin assays.

Question 12 What type of diarrheal illness produces fever, leukocytosis in peripheral blood, and fecal leukocytes? A. Diarrhea in which the mucosal surface is invaded B. Diarrhea in which the full bowel thickness is invaded C. Diarrhea caused by endotoxins D. Diarrhea caused by enterotoxins

A As opposed to the enterotoxin-mediated illnesses, organisms that invade the bowel mucosal surface cause an inflammatory response. This is manifested by the presence of fecal leukocytes, and the organisms may also cause fever and leukocytosis in peripheral blood.

Question 21 A microbiologist is reading a Gram stain and observes gram-negative, curved rods with a seagull-wing appearance. What is the most likely organism? A. Campylobacter or Vibrio B. Shigella or Vibrio C. Campylobacter or Shigella D. All of the above

A The bacterial pathogen may be visible on direct microscopic examination of the stool. If gram-negative, curved rods with a sea-gull-wing appearance are present, the patient may have a Campylobacter or Vibrio infection.

Question 19 What is the most commonly identified intestinal parasite in the United States? A. Giardia lamblia B. Entamoeba histolytica C. Cryptosporidium parvum D. Microsporidia

A The most commonly identified intestinal pathogen in the United States, G. lamblia, is acquired by ingestion of contaminated water and person-to-person spread.

Gram stain of a smear taken from the periodontal pockets of a 30-year-old man with poor dental hygiene showed sulfur granules containing gram-positive rods (short diphtheroids and some unbranched filaments). Colonies on blood agar resembled "molar teeth" in formation. The most likely organism is: A. Actinomyces israelii B. Propionibacterium acnes C. Staphylococcus intermedius D. Peptostreptococcus anaerobius

A A. israelii is part of the normal flora of the mouthand tonsils but may cause upper or lower respiratorytract infections. The sulfur granules are granularmicrocolonies with a purulent exudate. Like Nocardia,Actinomyces produces unbranched mycelia and issometimes (erroneously) considered a fungus. It hasalso been implicated in pelvic infection associatedwith intrauterine contraceptive devices (IUDs).

8. Egg yolk agar is used to detect which enzyme produced by Clostridium species? A. Lecithinase B. β-Lactamase C. Catalase D. Oxidase

A Egg yolk agar (modified McClung's or neomycinegg yolk agar) is used to determine the presence oflecithinase activity, which causes an insoluble,opaque, whitish precipitate within the agar. Lipaseactivity is indicated by an iridescent sheen or pearlylayer on the surface of the agar.

Which mechanism is responsible for botulism in infants caused by Clostridium botulinum? A. Ingestion of spores in food or liquid B. Ingestion of preformed toxin in food C. Virulence of the organism D. Lipase activity of the organism

A Infant botulism is the most frequent form occurringin the United States. Epidemiological studies havedemonstrated that infant botulism results from theingestion of spores via breastfeeding or exposure tohoney. Preformed toxin has not been detected infood or liquids taken by the infants. C. botulinummultiplies in the gut of the infant and produces theneurotoxin in situ.

3. Which of the following is the medium of choice for the selective recovery of gram-negative anaerobes? A. Kanamycin-vancomycin (KV) agar B. Phenylethyl alcohol (PEA) agar C. Cycloserine-cefoxitin-fructose agar (CCFA) D. THIO broth

A KV allows the growth of Bacteroides spp., Prevotellaspp., and Fusobacterium spp. and inhibits mostfacultative anaerobic gram-negative rods andgram-positive bacteria (both aerobic and anaerobic).PEA inhibits facultative gram-negative bacteria butwill support gram-positive aerobes and anaerobesand gram-negative obligate anaerobes. CCFA isselective for C. difficile from stool, while THIO brothsupports gram-positive and gram-negative aerobesand anaerobes.

The gram-positive non-spore-forming anaerobic rods most frequently recovered from blood cultures as a contaminant are: A. Propionibacterium acnes B. Clostridium perfringens C. Staphylococcus intermedius D. Veillonella parvula

A P. acnes is a nonspore former and is described as adiphtheroid-shaped rod. It is part of the normal skin,nasopharynx, genitourinary, and gastrointestinal tractflora but is implicated as an occasional cause ofendocarditis.

6. Which broth is used for the cultivation of anaerobic bacteria in order to detect volatile fatty acids as an aid to identification? A. Pre reduced peptone-yeast extract-glucose (PYG) B. THIO broth C. Gram-negative (GN) broth D. Selenite (SEL) broth

A Peptone yeast and chopped meat withcarbohydrates support the growth of anaerobicbacteria. The end products from the metabolism ofthe peptone and carbohydrates are volatile fatty acidsthat help to identify the bacteria. After incubation,the broth is centrifuged, and the supernatant injectedinto a gas-liquid chromatograph. Peaks for acetic,butyric, or formic acid, for example, can be identifiedby comparison to the elution time of volatile organicacid standards.

Which gram-negative bacilli produce blackpigment and brick red fluorescence when exposed to an ultraviolet light source? A. Porphyromonas spp. and Prevotella spp. B. Fusobacterium spp. and Actinomyces spp. C. Bacteroides spp. and Fusobacterium spp. D. All of these options

A Pigmenting Porphyromonas spp. and Prevotella spp.also show hemolysis on sheep blood agar.

Question 18 Bacteremias are least often associated with which of the following patient conditions? A. Those undergoing elective outpatient surgical procedures B. Patients undergoing bone marrow transplantation C. Those receiving immunosuppressive chemotherapy D. Patients with hematologic malignancies

ANS: A

Question 2 What defense mechanism does the colon have to guard against infection? A. IgA secretion B. IgE secretion C. Ciliated epithelial cells D. Acid secretion

ANS: A

Question 2 Why is pharyngitis produced by group A Streptococcus treated with antimicrobial agents? A. To prevent rheumatic fever and acute glomerulonephritis B. To prevent epiglottis C. To prevent swelling of the tonsils D. To prevent swelling of soft tissues in the pharynx

ANS: A

Question 12 What is the most commonly identified intestinal parasite in the United States? A. Giardia lamblia B. Entamoeba histolytica C. Cryptosporidium parvum D. Microsporidia

ANS: A

Question 16 Which of the following is an example of a primary bacteremia source? A. An infected heart valve B. A wound abscess C. A case of pneumonia D. A patient with hepatitis

ANS: A

12 A Corynebacterium species recovered from a throat culture is considered a pathogen when it produces: A. A pseudomembrane of the oropharynx B. An exotoxin C. Gray-black colonies with a brown halo on TInsdale's agar D. All of these options

ANS: A

A gram stained smear shows an organism isolated from a blood culture after bowel surgery. Under anaerobic incubation conditions, it grew as smooth, white, nonhemolytic colonies. The organism was not inhibited by colistin, kanamycin, or vancomycin and hydrolyzed esculin. The most likely identification of this isolate is which of the following? A. Bacteroides fragilis B. Fusobacterium nucleatum C. Fusobacterium varium D. Prevotella melaninogenica

ANS: A

Gram staining of a smear taken from the periodontal pockets of a 30-year-old man with poor dental hygiene showed sulfur granules containing gram-positive rods (short diphtheroids and some unbranched filaments) and were non-acid fast. Colonies on blood agar resembled "molar teeth" in formation. The most likely organism is: A. Actinomyces israelii B. Propionibacterium acnes C. Staphylococcus intermedius D. Peptostreptococcus anaerobius

ANS: A

Question 10 A college student is examined at the emergency department; he is disoriented with a fever, intense headache, stiff neck, vomiting, and sensitivity to light. His friends say that he has been sick for about 2 days and that his condition worsened over the last 3 hours. The serum electrolytes are normal, but the patient's white blood count is 12,000 cells/L. What test should the physician order next? LO 9; Level 3 A. CSF Gram stain and culture B. Stool Gram stain and culture C. Blood cultures × 3 D. Urinalysis and urine culture

ANS: A

Question 11 A microbiologist is working the miscellaneous bench reading stool cultures. The campy plate from a culture has growth on the plate that was incubated at 42° C. The colonies are nonhemolytic, moist, "runny looking," and spreading. The Gram stain shows tiny gram-negative rods with some S-shapes and seagull-wing shapes. What is growing on the plate? A. Campylobacter B. Helicobacter C. Aeromonas D. Acinetobacter

ANS: A

29. The clinical picture of this condition includes an incubation period of 2 to 10 days, fever, with or without cough, and dyspnea. The condition may resolve or progress to a more severe form. What is this condition? a. Severe acute respiratory syndrome (SARS) b. Streptococcal pneumonia c. Viral pneumonia d. Viral bronchitis

ANS: A A characteristic clinical picture is associated with SARS, although distinguishing SARS from other causes of pneumonia remains a challenge. After an incubation period of approximately 2 to 10 days, the most characteristic symptom is fever, with or without cough, or dyspnea. In most cases, symptoms resolve spontaneously after the first week; however, in more than 20% of patients, symptoms progress to the more severe respiratory distress syndrome, and patients require intensive care and respiratory support. REF: page 790 OBJ: Level 2 - Interpretation

15. The most common sites associated with bacteremia and sepsis include all the following EXCEPT: a. Reproductive organs b. Infected intravascular catheters c. The lung d. The abdomen

ANS: A A number of sources often give rise to bacteremia. The most common sites associated with bacteremia and sepsis are infected intravascular catheters, the urinary tract, the lung, and the abdomen. REF: page 874 OBJ: Level 1 -

31. Streptococcus pneumoniae and Streptococcus pyogenes use efflux as an effective mechanism for acquired resistance to a. macrolides. b. peptidoglycans. c. aminoglycosides. d. quinolones.

ANS: A Acquired macrolide resistance mediated by efflux, however, has recently been described in streptococci and is encoded by mefE in S. pneumoniae and by mefA in S. pyogenes. OBJ: Level 2: Interpretation

27. How is the true Gram stain reaction of an anaerobe determined? a. Special potency disks b. Shape and colony morphology c. Aerotolerance d. Direct fluorescent antibody (DFA)

ANS: A Although the Gram stain is helpful in the initial identification of an anaerobic isolate, certain species of Clostridium may stain pink and thus appear to be gram-negative bacilli. To determine the true Gram stain reaction of the isolate, special-potency disks can be used. OBJ: Level 1: Recall

5. Antibiotic mechanisms of action target all the following, except a. blocking the Embden-Meyerhof pathway. b. bacterial cell wall synthesis. c. DNA replication. d. RNA transcription.

ANS: A Although the classification scheme and number of antibiotics is complex and continues to expand as new classes emerge or existing classes are modified, their mechanisms of action target bacterial cell wall biosynthesis, folate synthesis, DNA replication, RNA transcription, and mRNA translation. These are logical targets critical to the survival of the microorganism. OBJ: Level 1: Recall

1. All the following are categories of bacterial growth requirements for oxygen and carbon dioxide, except a. ambient air (95% O2 and 5% CO2). b. microaerophilic (5% O2). c. anaerobic (0% O2). d. capnophilic (about 15% O2 and 5% to 10% CO2).

ANS: A Ambient air is usually 21% O2 and 1% CO2. OBJ: Level 1: Recall

5. Anaerobes outnumber aerobes in all of the following locations, except a. skin. b. oral cavity. c. gastrointestinal (GI) tract. d. genitourinary tract.

ANS: A Anaerobes outnumber aerobes at mucosal surfaces, such as the linings of the oral cavity, GI tract, and genitourinary tract. These heavily colonized surfaces are the usual portals of entry into the tissues and bloodstream for endogenous anaerobes. OBJ: Level 1: Recall

11. What type of diarrheal illness produces fever, leukocytosis in peripheral blood, and fecal leukocytes? a. Diarrhea in which the mucosal surface is invaded b. Diarrhea in which the full bowel thickness is invaded c. Diarrhea caused by endotoxins d. Diarrhea caused by enterotoxins

ANS: A As opposed to the enterotoxin-mediated illnesses, organisms that invade the bowel mucosal surface cause an inflammatory response. This is manifested by the presence of fecal leukocytes and may also cause fever and leukocytosis in peripheral blood. REF: page 841 OBJ: Level 2 - Interpretation

20. Which of the following is considered a better specimen for anaerobic culture than a swab? a. Aspirate b. Washing c. Scraping d. Lavage

ANS: A Aspirates, specimens collected by needle and syringe, are better for anaerobic bacteriology than those collected by swab. They are less likely to be contaminated by indigenous microbiota, including endogenous anaerobes, and provide a larger quantity of material. OBJ: Level 1: Recall

1. Where does primary bacteremia arise from? a. An endovascular source b. The lung c. The liver d. The gastrointestinal tract

ANS: A Bacteremia may be classified by its site of origin. Primary bacteremia arises from an endovascular source such as an infected cardiac valve or an infected intravenous catheter, whereas secondary bacteremia arises from an infected extravascular source, such as the lung in patients with pneumonia; a case in which the source of bacteremia remains undefined is termed bacteremia of unknown origin. REF: page 870 OBJ: Level 1 -

Question 7 Meningitis following bacteremia and septicemia are often associated with Neisseria meningitidis and A. Streptococcus pneumoniae. B. Escherichia coli. C. Pseudomonas aeruginosa. D. Staphylococcus aureus.

ANS: A Bacteria in the blood stream can occasionally cross the blood-brain barrier. N. meningitidis and S. pneumoniae are common causes of meningitis in adults. These bacteria can inhabit the nasopharynx and cause pneumonia.

Question 14 What is the principle of a continuous monitoring blood culture system? A. The amount of CO2 produced is measured as a growth index and compared with a threshold. B. The amount of increased lipopolysaccharide is measured and compared against the null value. C. The pH of the media is continuously measured to check for bacterial metabolic by-products. D. An optical monitor records the number of bacteria and records the growth.

ANS: A Bacteria typically produce CO2 as a by-product of metabolism. Instruments monitor CO2 production by several different mechanisms. The amount of CO2 produced is measured as growth index and compared with an established threshold level.

13. An Older adult patient in a nursing home is recovering from bacterial pneumonia. The patient has been on a lengthy regiment of antimicrobial agents. Subsequently, the patient is diagnosed with pseudomembranous colitis. What organism is the most likely cause? a. Clostridium difficile b. C. tetani c. C. perfringens d. C. botulinum

ANS: A C. difficile is the most common but not the sole cause of antibiotic-associated diarrhea and pseudomembranous colitis. Following antimicrobial therapy, many organisms of the GI biota other than C. difficile are killed, thus allowing C. difficile to multiply and produce abundant quantities of two types of toxins: toxin A and toxin B. Bloody diarrhea, with associated necrosis of colon mucosa, is seen in patients with pseudomembranous colitis. OBJ: Level 3: Synthesis

An older adult patient in a nursing home is recovering from bacterial pneumonia. The patient has been on a lengthy regiment of antimicrobial agents. Subsequently, the patient is diagnosed with pseudomembranous colitis. What organism is the most likely cause? A. Clostridium difficile B. C. tetani C. C. perfringens D. C. botulinum

ANS: A C. difficile is the most common but not the sole cause of antibiotic-associated diarrhea and pseudomembranous colitis. Following antimicrobial therapy, many organisms of the GI biota other than C. difficile are killed, thus allowing C. difficile to multiply and produce abundant quantities of two types of toxins: toxin A and toxin B. Bloody diarrhea, with associated necrosis of colon mucosa, is seen in patients with pseudomembranous colitis.

16. What fungus causes chronic meningitis in HIV patients? a. Cryptococcus neoformans b. Coccidioides immitis c. Candida albicans d. Histoplasma capsulatum

ANS: A C. neoformans is an encapsulated basidiomycetous yeast. It can spread hematogenously to the central nervous system (CNS) from pulmonary foci and can cause chronic meningitis, particularly in patients with AIDS. REF: page 861 OBJ: Level 1 - Recall

23. What specimen reduces the risk of contamination with urethral florae? a. Catheterized specimen b. Suprapubic aspirate c. First morning specimen d. Voided midstream specimen

ANS: A Catheterized specimen collection, which is an invasive technique, reduces the risk of contamination of urine with the urethral florae; however, because the catheter is passed through the urethra, some contamination may occur. REF: page 894 OBJ: Level 1 - Recall

37. After 24-hour incubation, an SBA from a vaginal culture reveals heavy growth of B-hemolytic, pinpoint, rough colonies. A catalase test is performed, and it is negative. What organism should you suspect? a. Lactobacillus b. Diphtheroids c. Listeria d. Arcanobacterium

ANS: A Colony morphology of Lactobacillus varies and ranges from -hemolytic, pinpoint in size to rough and gray in color. Catalase is negative and, unless a Gram stain is performed, differentiation from Streptococcus sp. viridans group is difficult. OBJ: Level 3: Synthesis

Question 5 After 24-hour incubation, an SBA from a vaginal culture reveals heavy growth of α-hemolytic, pinpoint, rough colonies. A catalase test is performed, and it is negative. What organism should you suspect? A. Lactobacillus B. Diphtheroids C. Listeria D. Arcanobacterium

ANS: A Colony morphology of Lactobacillus varies and ranges from α-hemolytic, pinpoint in size to rough and gray in color. Catalase is negative and, unless a Gram stain is performed, differentiation from Streptococcus sp. viridans group is difficult.

16. All of the following are complications of acute sinusitis EXCEPT: a. Acute pharyngitis b. Meningitis c. Osteomyelitis d. Orbital cellulitis

ANS: A Complications of acute sinusitis result from extension of the infection to adjacent areas or structures. These complications include orbital cellulitis, osteomyelitis, meningitis, brain abscess, and cavernous sinus thrombosis. REF: page 781 OBJ: Level 1 - Recall

18. What is the most sensitive method of diagnosing cutaneous infections? a. Culture b. Enzyme immunoassay (EIA) c. Polymerase chain reaction (PCR) d. DNA probe

ANS: A Culture is still the most sensitive method of diagnosing cutaneous infections. Agents of primary infections are recovered in routine culture using primary nonselective media, such as blood and chocolate agars, and selective media, such as MacConkey agar. REF: page 833 OBJ: Level 1 - Recall

8. What bacteria may cause up to 50% of all cases of pneumonia in the summer months? a. Mycoplasma pneumoniae b. Streptococcus pneumoniae c. Klebsiella pneumoniae d. Haemophilus influenzae

ANS: A Diseases associated with M. pneumoniae typically occur throughout the year, without marked seasonal variability. The incidence of viral infections and secondary bacterial pneumonias is reduced during the summer months; therefore M. pneumoniae may cause up to 50% of all pneumonias in the summer months. REF: page 776 OBJ: Level 1 - Recall

24. What diarrheal pathogen can produce a disease that may lead to hemolytic-uremic syndrome (hemolytic anemia, low platelet count, and kidney failure)? a. Enterohemorrhagic Escherichia coli (EHEC) b. Enteroinvasive E. coli (EIEC) c. Enteropathogenic E. coli (EPEC) d. Enterotoxigenic E. coli (ETEC)

ANS: A EHEC usually starts as a watery diarrhea. However, over the next day or two, abdominal pain increases and stools become bloody. Stool may contain some fecal leukocytes, so there may be some confusion between this infection and EIEC or Shigella. Although the disease is usually self-limited, patients can develop hemolytic-uremic syndrome (HUS), characterized by hemolytic anemia, low platelet count, and kidney failure. REF: page 844 OBJ: Level 2 - Interpretation

14. What organisms usually cause urinary tract infections (UTIs) in older men in conjunction with prostatic hypertrophy? a. Enterococcus spp. b. Staphylococcus epidermidis c. Streptococcus agalactiae d. Escherichia coli

ANS: A Enterococcal UTIs occur primarily in older men, particularly in association with urinary tract manipulation or instrumentation or prostatic hypertrophy. REF: page 891 OBJ: Level 1 - Recall

10. All of the following organisms can cause enterotoxin-mediated diarrhea EXCEPT: a. Salmonella typhi b. Clostridium perfringens c. Vibrio cholerae d. Staphylococcus aureus

ANS: A Enterotoxigenic E. coli accounts for the largest percentage of cases of diarrhea in travelers to underdeveloped areas. Other organisms responsible for enterotoxin-mediated disease are Vibrio cholerae, Staphylococcus aureus, Clostridium perfringens, and Bacillus cereus. REF: page 840 OBJ: Level 1 - Recall

26. What causes erythema infectiosum? a. Parvovirus b. Herpesvirus c. Paramyxovirus d. Togaviridae

ANS: A Erythema infectiosum, or fifth disease, is one of the common viral exanthematous diseases of childhood. Caused by the human parvovirus B19, epidemic or sporadic disease is characterized by a striking erythema of the face (the so-called slapped cheek appearance), followed in 1 to 4 days by a fine, lacelike rash on the trunk or extremities. REF: page 824 OBJ: Level 1 - Recall

11. Lesions from which bacteria fluoresce coral red when examined under a Wood's lamp? a. Corynebacterium minutissimum b. Staphylococcus aureus c. Clostridium tetani d. C. difficile

ANS: A Erythrasma is a chronic, pruritic, reddish brown macular infection found most commonly in men and obese patients with diabetes mellitus. The infection typically is located in intertriginous areas such as the groin, toe web, axilla, and inframammary folds. The lesions produce a coral-red fluorescence when examined under a Wood's lamp. REF: page 811 OBJ: Level 2 - Interpretation

Question 10 Which of the following is the medium of choice for the selective recovery of gram-negative anaerobes? A. Kanamycin-vancomycin-anaerobe (KVA) agar B. Phenylethyl alcohol (PEA) agar C. Cycloserine cefoxitin fructose agar (CCFA) D. THIO broth

ANS: A KVA allows growth of Bacteroides spp., Prevotella spp., and Fusobacterium spp. and inhibits most facultative anaerobic gram-negative rods and gram-positive bacteria (both aerobic and anaerobic). PEA inhibits facultative gram-negative bacteria but will support gram-positive aerobes and anaerobes and gram-negative obligate anaerobes. CCFA is selective for C. difficile from stool, whereas THIO broth supports gram-positive and gram-negative aerobes and anaerobes.

1. When reading culture plates from respiratory specimens, what must the microbiologist take into consideration? a. The types of organisms normally found at the culture site b. The amount of media inoculated c. The quality control performed on the media d. The patient's physician

ANS: A Laboratory professionals must consider the types of organism normally found at the site from which a microbiologic specimen was collected to be able to determine whether diagnostic data indicate the presence of a pathogen. Analysis of microbiologic data requires a working knowledge of the normal microbial florae, the clinical setting, and the patient's presentation. REF: page 773 OBJ: Level 2 - Interpretation

13. What virus is an uncommon cause of aseptic meningitis that can be acquired from dust or food contaminated with urine or feces from infected rodents and hamsters? a. Lymphocytic choriomeningitis virus b. Epstein-Barr virus c. Guillain-Barré virus d. Astrovirus

ANS: A Lymphocytic choriomeningitis virus is a member of the Arenaviridae family. It is an RNA virus that is an uncommon cause of aseptic meningitis in humans. The virus is shed in the urine and other excretions of infected rodents and hamsters. Humans are infected by aerosol or by ingestion of dust or food contaminated with the urine, feces, blood, or nasopharyngeal secretions of infected rodents. REF: page 860 OBJ: Level 2 - Interpretation

18. The members of the macrolide class of antibiotics include all the following, except a. rifamycin. b. erythromycin. c. clarithromycin. d. azithromycin.

ANS: A Macrolides such as erythromycin, clarithromycin, and azithromycin target the 50S subunit specifically by binding to the peptidyl transferase cavity on the rRNA. OBJ: Level 1: Recall

21. What organism that causes gastroenteritis can be found in aquaculture-farmed fish? a. Salmonella b. Campylobacter c. Vibrio d. Shigella

ANS: A Nontyphoidal Salmonella spp. can lead to gastroenteritis through ingestion of contaminated meat, poultry, eggs, and dairy products, as well as aquaculture-farmed fish and shellfish. REF: pages 842-843 OBJ: Level 2 - Interpretation

24. This type of pathogen may demonstrate decreases or loss of porin synthesis in combination with other resistance mechanisms, resulting in multidrug-resistant pathogens. a. Nosocomial b. Community-acquired c. Emerging d. Gram-negative

ANS: A Nosocomial pathogens showing decreases or loss of porin synthesis are observed in combination with other resistance mechanisms, resulting in multidrug-resistant pathogens. In addition, the molecular size and lipophilic state affect the rate at which antibiotics traverse porins. OBJ: Level 1: Recall

10. What disease does Clostridium botulinum cause? a. Botulism b. Tetanus c. Lyme disease d. Myonecrosis

ANS: A Occasionally, intoxication may follow ingestion of preformed toxins produced by exogenous anaerobes. Foodborne botulism results from the ingestion of preformed botulinum toxin, a toxin produced in the food by C. botulinum. Seven antigenically different botulinum toxins, A-E, are known. OBJ: Level 1: Recall

33. What organism is the most common opportunistic pathogen that routinely infects patients with HIV/AIDS? a. Pneumocystis carinii b. Mycoplasma pneumoniae c. Serratia marcescens d. Respiratory syncytial virus (RSV)

ANS: A P. carinii pneumonia remains the most common AIDS-associated opportunistic infection, although its incidence has decreased. REF: page 801 OBJ: Level 1 - Recall

17. What is a symptom of tertiary syphilis? a. Gummas b. Chancre c. Genital warts d. Strokes

ANS: A Patients with late syphilis may develop neurologic symptoms or cardiovascular effects, or they may experience late benign syphilis. In the latter condition, the patient develops gummas, which are nonspecific granulomatous lesions. Gummas can occur in skin, bone, or viscera. REF: page 916 OBJ: Level 1 - Recall

40. Plasmids are a. circular structures present in bacteria that contain genes encoding proteins and DNA and have the capacity to self-replicate and portion into daughter cells during cellular division. b. DNA elements that encode transposition and excision function and can transpose from one place on the chromosome to another. c. genetic elements capable of integrating resistance genes (cassettes) by an integron-encoded, site-specific recombinase. d. DNA elements found in bacteria that carry genes only for the enzymes needed to promote their own transposition.

ANS: A Plasmids are extrachromosomal DNA, circular structures present in bacteria that contain genes encoding proteins and RNA and have the capacity to self-replicate and partition into daughter cells during cellular division. Plasmids also acquire and exchange information with the chromosome and other host resident plasmids, including antibiotic resistance genes. OBJ: Level 1: Recall

22. What type of a device can cause osteomyelitis, which will then lead to bacteremia? a. Prosthetic joints b. Stainless steel rods c. Orthopedic screws d. Orthopedic plates

ANS: A Prosthetic joints, particularly those implanted in the hip, can be hematogenously seeded by organisms such as Staphylococcus aureus and coagulase-negative staphylococcus and then give rise to bacteremia. REF: page 875 OBJ: Level 2 - Interpretation

Question 9 What type of a medical implant device is commonly associated with osteomyelitis, which will then lead to bacteremia? A. Prosthetic joints B. Stainless steel rods C. Orthopedic screws D. Orthopedic plates

ANS: A Prosthetic joints, particularly those implanted in the hip, can be hematogenously seeded by organisms, such as Staphylococcus aureus and coagulase-negative staphylococci, and then give rise to bacteremia.

1. Why is the travel history of the patient important when evaluating a person with diarrhea? a. Travel to different countries puts one at risk for various infections. b. Some countries are dirtier than others. c. The Unites States is clean, and usually bad infections cannot be contracted here. d. All of the above.

ANS: A Recent travel history is also important, as travelers to underdeveloped areas are at risk for various types of infections. REF: page 837 OBJ: Level 2 - Interpretation

14. This antibiotic interferes with DNA transcription by blocking of RNA chain elongation. a. Rifampin b. Quinolone c. Trimethoprim d. Glycopeptide

ANS: A Rifampin, a synthetic derivative of rifamycin B, is used in combination with other antibiotic classes to treat Mycobacterium tuberculosis by targeting transcription of DNA. The target of rifampin in M. tuberculosis is the RNA polymerase subunit at an allosteric site, with the subsequent blocking of RNA chain elongation. As a result, RNA transcription is aborted at the initiation step. OBJ: Level 1: Recall

5. What organism is the most common cause of meningitis in adults? a. Streptococcus pneumoniae b. Pseudomonas aeruginosa c. Haemophilus influenzae d. Neisseria meningitidis

ANS: A S. pneumoniae is a gram-positive diplococcus and is the most common cause of meningitis in adults and the second most common cause of meningitis in children. REF: page 858 OBJ: Level 1 - Recall

27. All of the following types of specimens should not be treated as screens EXCEPT: a. Urine specimens with significant pyuria and bacteriuria b. Straight catheterization c. Suprapubic aspiration d. Cystoscopy

ANS: A Screening methods are not appropriate for urine collected by straight catheterization, cystoscopy, suprapubic aspiration, and bladder washout or for test of cure specimens and specimens collected from ileoconduits. REF: page 896 OBJ: Level 1 - Recall

4. What is a form of folliculitis in bearded men? a. Sycosis barbae b. Furuncle c. Carbuncle d. Impetigo

ANS: A Sycosis barbae is a form of folliculitis occurring in bearded men. REF: page 814 OBJ: Level 1 - Recall

33. All of the following reasons are cited for performing antimicrobial susceptibility testing on anaerobes by the Clinical and CLSI, except a. to determine the resistance mechanisms in anaerobes. b. to assist in the management of patients with serious illnesses. c. to monitor local and regional resistance patterns. d. to determine susceptibility of anaerobes to new antimicrobials.

ANS: A The CLSI cites the following major reasons for susceptibility testing of anaerobic isolates: to assist in the management of infection in individual patients with serious or life-threatening infections, to periodically monitor local and regional resistance patterns so that such information is available as a guide for empiric antimicrobial choice, and to determine patterns of susceptibility of anaerobes to new antimicrobial agents as they are approved for treatment of infections involving anaerobes. OBJ: Level 2: Interpretation

32. A microbiologist is reading a Gram stain and observes gram-negative, curved rods with a seagull-wing appearance. What organism could this be? a. Campylobacter and Vibrio b. Shigella and Vibrio c. Campylobacter and Shigella d. All of the above

ANS: A The bacterial pathogen may be visible on direct microscopic examination of the stool. If gram- negative, curved rods with a sea-gull-wing appearance are present, the patient may have a Campylobacter or Vibrio infection. REF: page 844 OBJ: Level 2 - Interpretation

5. What defense mechanism does the colon have to guard against infection? a. IgA antibody is produced. b. IgE antibody is produced. c. Nonspecific immune defenses are resident here and take care of pathogens. d. The anatomic structure makes it tough for organisms to adhere.

ANS: A The colon also has defense mechanisms. Antibody is produced locally—primarily IgA—which may have some effect against pathogenic organisms. Also, an enormous number of other bacteria already live in the colon (the host's normal gut flora). REF: page 837 OBJ: Level 1 - Recall

5. The atypical clinical presentation of a geriatric patient with a urinary tract infection (UTI) includes all the following EXCEPT: a. Burning upon urination b. Delirium c. Fever d. Failure to thrive

ANS: A The diagnosis and management of UTI in the geriatric population can be challenging. These patients frequently have an atypical clinical presentation including delirium, fevers alone, or failure to thrive. REF: page 888 OBJ: Level 1 - Recall

25. How is acute bronchitis differentiated from acute pneumonia? a. The degree and extent of involvement of the lower respiratory tract with the infectious process b. The involvement of the bronchial tree with the infectious process c. The degree of obstruction of the alveoli with the purulent secretions d. The amount of mucus secretion produced by the lower respiratory tract

ANS: A The distinction between acute bronchitis and acute pneumonia may be subtle. Both of these conditions are lower respiratory tract infections. The differentiation between acute bronchitis and pneumonia depends on the degree and extent of involvement of the lower respiratory tract with the infectious process. REF: page 786 OBJ: Level 2 - Interpretation

9. What enterovirus is commonly associated with neurologic illness? a. Coxsackievirus B b. Parvovirus c. Herpesvirus 1 d. Calicivirus A

ANS: A The enteroviruses frequently associated with neurologic illness include coxsackievirus B and echovirus. REF: page 859 OBJ: Level 1 - Recall

24. When drawing blood for blood cultures in a child younger than age 10, how much blood do you draw? a. 1 mL for each year of life b. 5 mL c. 2 mL d. 1 mL for children younger than 2 years old, 3 mL for children younger than 7 years old, and 5 mL for children up to 10 years old

ANS: A The following age-volume protocol has been recommended: younger than age 10, 1 mL of blood for each year of life; 10 years old or older, 20 mL; and 10 years old or older (poor veins), less than 20 mL. This protocol is based on studies that have demonstrated that as the volume of blood cultured increases from 2 to 20 mL, the yield of positive culture results increases from 30% to 50%, except in newborns. REF: page 876 OBJ: Level 1 -

12. Why is pharyngitis produced by group A streptococcus treated with antibiotics? a. To prevent rheumatic fever and acute glomerulonephritis b. To prevent epiglottis c. To prevent swelling of tonsils d. To prevent swelling of soft tissues in the pharynx

ANS: A The goals of antibiotic treatment of streptococcal pharyngitis include amelioration of the symptoms, limitation of transmission of the infection to contacts (especially in school-age children), and prevention of the serious complications of acute rheumatic fever and acute glomerulonephritis. REF: page 779 OBJ: Level 2 - Interpretation

23. What is the ideal anaerobic incubation system? a. Anaerobic chamber b. Anaerobic jars c. Anaerobic bags d. Candle jars

ANS: A The ideal anaerobic incubation system is an anaerobic chamber, which provides an oxygen-free environment for inoculating media and incubating cultures. OBJ: Level 1: Recall

5. All of the following factors can help the microbiologist differentiate between colonization and infection, EXCEPT: a. Presence of a pure culture or mixed florae on the culture plates b. Method and site of collection of the specimen c. Presence of white blood cells (WBCs) and the number of organisms seen on Gram stain d. A compatible clinical syndrome

ANS: A The isolation of certain organisms from respiratory specimens may represent either colonization or disease, depending on the circumstances. An interpretation must be based on several factors. The method and site of collection of the specimen can influence the risk of contamination with organisms that are part of the normal florae. Characteristics of the specimen such as the presence of white blood cells and the number of organisms in the specimen can help distinguish between colonization and infection. Most important, a compatible clinical syndrome should be present to determine whether the presence of a potential pathogen is clinically relevant. REF: page 775 OBJ: Level 2 - Interpretation

30. What is swimmer's itch? a. When cercariae larvae penetrate human skin, causing dermatitis b. When arthropods deposit larvae in human skin, causing dermatitis c. When food or water causes a dermatitis d. When Pseudomonas spp. causes a dermatitis

ANS: A The larvae of certain schistosomes of birds and mammals may penetrate the human skin and cause a dermatitis sometimes known as swimmer's itch. REF: page 828 OBJ: Level 1 - Recall

28. What is the most commonly identified intestinal parasite in the United States? a. Giardia lamblia b. Entamoeba histolytica c. Cryptosporidium parvum d. Microsporidia

ANS: A The most commonly identified intestinal pathogen in the United States, G. lamblia, is acquired by ingestion of contaminated water and person-to-person spread. REF: page 846 OBJ: Level 1 - Recall

20. All of the following are recently approved classes of antibiotics that target protein synthesis, except a. sixth generation cephalosporins. b. oxazolidinones. c. streptogramin. d. glycylcycline.

ANS: A The most recently approved classes of antibiotics targeting protein synthesis are oxazolidinones (linezolid), streptogramin (dalfopristin-quinupristin), and glycylcycline (tigecycline). OBJ: Level 1: Recall

8. The outer membrane of gram-negative bacteria is composed of a. lipopolysaccharides, phospholipids, and porin proteins. b. peptidoglycan, phospholipids, and proteins. c. enzymes, cholesterol, and carbohydrates. d. carbohydrates, peptidoglycan, and proteins.

ANS: A The outer membrane of gram-negative bacteria is composed of lipopolysaccharides, phospholipids, and porin proteins, and it is separated from the cytoplasmic membrane by periplasmic space. OBJ: Level 1: Recall

5. What percentage of patients that are positive for Neisseria gonorrhea also have genital chlamydiosis? a. 30% b. 50% c. 20% d. 70%

ANS: A The recommended treatment for gonorrhea is currently cefixime or ceftriaxone with doxycycline. The doxycycline is used essentially to treat chlamydiosis in the patient because as many as 30% of patients with gonorrhea may also have genital chlamydiosis. REF: page 905 OBJ: Level 1 - Recall

16. What organism produces "ratbite fever"? a. Streptobacillus moniliformis b. Staphylococcus aureus c. Borrelia burgdorferi d. Chlamydia trachomatis

ANS: A Two bacterial diseases, rare in the United States, are included under the general term "ratbite fever": streptobacillus is caused by Streptobacillus moniliformis, and spirillosis is caused by Spirillum minus (minor). REF: page 822 OBJ: Level 1 - Recall

18. What organism is most commonly associated with bacteremia caused by acute pyelonephritis? a. Escherichia coli b. Enterobacter aerogenes c. Pseudomonas aeruginosa d. Staphylococcus aureus

ANS: A Urinary tract infections account for roughly 17% of all bacteremias. Infection of the upper urinary tract (acute pyelonephritis) leads to bacteremia in up to 40% of affected patients. E. coli is the most common cause of bacteremia in this setting. REF: page 874 OBJ: Level 1 -

19. Urine cultures are performed for all the following reasons EXCEPT: a. To test for chlamydia b. To confirm a cure c. To detect asymptomatic bacteriuria in pregnant women d. To evaluate for bacteremia

ANS: A Urine cultures are requested not only in connection with the symptoms of acute urinary tract infection (UTI) but also in the absence of specific symptoms, as a test of cure, to evaluate the effectiveness of antimicrobial therapy, to detect asymptomatic bacteriuria in pregnant women, and to evaluate for bacteremia , fever, or both, to name but a few instances. REF: page 894 OBJ: Level 1 - Recall

1. What is the most common bacterium found on the skin? a. Coagulase-negative staphylococci b. Coagulase-negative streptococci c. Escherichia coli d. Pseudomonas aeruginosa

ANS: A Usual florae of the skin consists of those microbes able to adapt to the high salt concentration and drying effects of the skin. Important microflorae include gram-positive cocci such as staphylococci and streptococci. Coagulase-negative staphylococci, such as Staphylococcus epidermidis, are permanent skin residents; coagulase-positive Staphylococcus aureus is a transient colonizer. REF: page 808 OBJ: Level 1 - Recall

12. What organism is known to cause severe necrotic cellulitis and primary sepsis? a. Vibrio vulnificus b. V. parahaemolyticus c. Campylobacter spp. d. Staphylococcus aureus

ANS: A V. vulnificus, a halophilic vibrio, has been recognized as a virulent pathogen since 1976 when it was first described. The organism is known to cause severe necrotic cellulitis and primary sepsis. REF: page 819 OBJ: Level 1 - Recall

12. What cells are found in bacterial vaginosis? a. Clue cells b. Lymphocytes c. Macrophages d. Squamous epithelial cells

ANS: A Vaginal fluid has an increased pH and contains clue cells, which are exfoliated vaginal epithelial cells literally covered by gram-negative coccobacilli and curved gram-negative rods. REF: page 906 OBJ: Level 1 - Recall

21. What of the following methods is considered the "gold standard" for diagnosing genital herpes? a. Viral isolation b. Enzyme immunoassay (EIA) c. Polymerase chain reaction (PCR) d. GenProbe

ANS: A Viral isolation is considered the gold standard method by CDC for the diagnosis of herpes simplex virus (HSV) infections. The best specimens for culture are vesicle fluids collected with syringe or swab. REF: page 913 OBJ: Level 1 - Recall

Question 4 CSF specimens should be analyzed for infectious agents as quickly as possible. How should a specimen collected in the hospital be transported to the laboratory? A. Wet ice B. Room temperature C. Dry ice D. Bacteriologic transport medium

ANS: B

Question 8 What virus, spread by the mosquito, causes a typically self-limiting illness, but can be associated with a rash, aseptic meningitis, myelitis, and fatal encephalitis? A. WNV B. Eastern equine encephalitis C. Colorado tick fever D. Venezuelan equine encephalitis

ANS: A WNV is a mosquito-borne flavivirus that commonly causes a self-limiting febrile illness, often associated with a rash. In 1999 the virus was introduced in the United States; it quickly spread throughout the United States. Neurologic involvement includes aseptic meningitis, myelitis, and fatal encephalitis. The mortality rate is about 5%, and death occurs mainly in older patients.

21. What virus, spread by the mosquito, causes a self-limiting illness that is associated with a rash, aseptic meningitis, myelitis, and fatal encephalitis? a. West Nile virus b. Eastern equine encephalitis c. Colorado tick fever d. Venezuelan equine encephalitis

ANS: A West Nile virus is a mosquito-borne flavivirus that commonly causes a self-limited febrile illness, often associated with a rash. In 1999, the virus was introduced in the United States and has spread rapidly since. Neurologic involvement includes aseptic meningitis, myelitis, and fatal encephalitis. REF: pages 860, 864 OBJ: Level 2 - Interpretation

29. What is the principle of a continuous monitoring blood culture system? a. The amount of 14CO2 produced is measured as a growth index and compared with a threshold. b. The amount of increased lipopolysaccharide is measured and compared against the null value. c. The pH of the media is continuously measured to check for bacterial metabolic by- products. d. An optical monitor records the number of bacteria and records the growth.

ANS: A When the organism in the blood culture bottle uses 14CO2-labeled substrate, 14CO2 is released. The instrument monitors CO2 production by aspirating gas into an ionization chamber using sterile needles. In the ionization chamber, the amount of 14CO2 produced is measured as growth index and compared with an established threshold level. REF: page 878 OBJ: Level 1 -

22. What disease results from a reactivation of the varicella-zoster virus that demonstrates a vesicular eruption in a unilateral dermatomal distribution? a. Shingles b. Chicken pox c. Infectious mononucleosis d. Rubella

ANS: A With reactivation, the virions move along peripheral sensory nerves of the skin, leading to the appearance of a vesicular eruption in a unilateral dermatomal distribution. The resulting condition is called shingles. REF: page 825 OBJ: Level 2 - Interpretation

A superficial form of cellulitis can cause a(n): A. furuncle B. erysipelas C. carbuncle D. paronychia

ANS: B

Question 1 All of these patient history questions will help focus the search for the cause of diarrhea, except: A. Does the patient have a history of previous gastrointestinal symptoms? B. Did the patient eat any hot food? C. Does the patient have an underlying illness? D. Is the patient taking any medication?

ANS: B

Question 10 A 21 year old patient presents with pharyngitis. A throat swab is collected and submitted for anaerobic culture. This specimen should be: A. set up immediately B. rejected as unacceptable C. inoculated into thioglycolate broth D. sent to a reference lab

ANS: B

Question 11 Primary atypical pneumonia is caused by: A. Streptococcus pneumoniae B. Mycoplasma pneumoniae C. Klebsiella pneumoniae D. Mycobacterium tuberculosis

ANS: B

Question 12 All of the following organisms are noted colonizers of indwelling catheters, except A. coagulase-negative staphylococci. B. Streptococcus pyogenes. C. Staphylococcus aureus. D. Enterococcus spp.

ANS: B

Question 12 In what suspected condition should a wet prep using a warm slide be examined? A. Cryptococcal meningitis B. Amoebic meningoencephalitis C. Mycobacterium tuberculosis infection D. Neurosyphilis

ANS: B

Question 12 The classic form of foodborne botulism is characterized by the ingestion of: A. Spores in food B. Preformed toxin in food C. Toxin H D. All of these options

ANS: B

Question 13 Common sites associated with bacteremia and sepsis include all the following, except A. the lung. B. reproductive organs. C. the abdomen. D. infected intravascular catheters.

ANS: B

Question 13 Nosocomial pneumonia is commonly caused by all of the following, except A. Pseudomonas aeruginosa. B. Streptococcus pneumoniae. C. Acinetobacter baumannii. D. Methicillin-resistant Staphylococcus aureus.

ANS: B

Question 14 The urea breath test is a noninvasive test to detect infection caused by A. Listeria monocytogenes. B. Helicobacter pylori. C. Vibrio cholerae. D. Campylobacter jejuni.

ANS: B

Question 15 A small, gram-negative coccobacillus recovered from the CSF of a 2-year-old unvaccinated child gave the following results: Indole = + X requirement = + Urease = + Sucrose = Neg Glucose = + (acid) V requirement = + Lactose = Neg Hemolysis = Neg Which is the most likely identification? A. Haemophilus parainfluenzae B. Haemophilus influenzae C. Haemophilus ducreyi D. Aggregatibacter (formerly Haemophilus) aphrophilus

ANS: B

Question 20 Which of the following has been suggested as a biomarker of fungal sepsis? A. C-reactive protein B. (1-3)-β-D-Glucan C. All of the above D. Procalcitonin

ANS: B

Question 22 Which of the following is correct regarding vancomycin? A. It inhibits DNA gyrase activity. B. It has a gram-positive spectrum, including MRSA, coagulase-negative staphylococci infections, and Clostridium difficile colitis. C. It is effective against anaerobes and intracellular pathogens. D. It inhibits protein synthesis.

ANS: B

Question 3 A teenager and her friends spend the day swimming in a lake and picnicking. The next day, she starts to feel sick complaining of a headache and general malaise. The following morning, she is very ill and is rushed to the emergency department. Many neurologic changes are noted. Despite the staff's best efforts, she dies. Autopsy reveals the presence of small protozoa in her brain tissue. What is the most probable organism that caused her death? A. Acanthamoeba spp. B. Naegleria fowleri C. Angiostrongylus cantonensis D. Balamuthia mandrillaris

ANS: B

Question 3 What are the two most frequently identified bacterial causes of community-acquired sinusitis? A. Staphylococcus aureus and Escherichia coli B. Streptococcus pneumoniae and Haemophilus influenzae C. S. pneumoniae and Mycoplasma pneumoniae D. H. influenzae and Neisseria meningitidis

ANS: B

16. All of the following organisms are colonizers of indwelling catheters EXCEPT: a. Coagulase-negative staphylococci b. Streptococcus pyogenes c. Staphylococcus aureus d. Enterococcus spp.

ANS: B As useful as indwelling catheters are, they are highly vulnerable to colonization and infection by organisms such as coagulase-negative staphylococci, S. aureus, and Enterococcus spp., with subsequent spread to the bloodstream to cause bacteremia; frequently, the strains causing a catheter-related bloodstream infection are resistant to multiple antibiotics. REF: page 874 OBJ: Level 1 -

2. Where does secondary bacteremia arise from? a. An infected cardiac valve b. The lung c. An infected intravenous catheter d. The bone marrow

ANS: B Bacteremia may be classified by its site of origin. Primary bacteremia arises from an endovascular source, such as an infected cardiac valve or an infected intravenous catheter, whereas secondary bacteremia arises from an infected extravascular source, such as the lung in patients with pneumonia; a case in which the source of bacteremia remains undefined is termed bacteremia of unknown origin. REF: page 870 OBJ: Level 1 -

Which of the following is an example of a secondary bacteremia source? A.An infected cardiac valve B. The lung C. An infected intravenous catheter D. The bone marrow

ANS: B Bacteremia may be classified by its site of origin. Primary bacteremia arises from an endovascular source, such as an infected cardiac valve or an infected intravenous catheter, whereas secondary bacteremia arises from an infected extravascular source, such as the lung in patients with pneumonia; a case in which the source of bacteremia remains undefined is termed bacteremia of unknown origin.

7. Bacteremias are more frequent among persons with the following conditions EXCEPT: a. Hematologic malignancies b. AIDS c. Those receiving immunosuppressive chemotherapy d. Those undergoing bone marrow transplantation

ANS: B Bacteremias are more frequent among persons with neoplasia, especially those with hematologic malignancies, those receiving immunosuppressive chemotherapy, and those undergoing bone marrow transplantation. REF: page 872 OBJ: Level 1 -

10. Bacteria gain access to the urinary tract by all of the following routes EXCEPT: a. The ascending route b. The neurologic route c. The hematogenous route d. The lymphatic pathways

ANS: B Bacteria gain access to the urinary tract by three different routes, the ascending route, the hematogenous route, and the lymphatic pathways. REF: page 890 OBJ: Level 1 - Recall

18. What organism causes chancroid? a. Treponema pallidum b. Haemophilus ducreyi c. Mobiluncus d. Gardnerella vaginalis

ANS: B Chancroid, or soft chancre, is a sexually transmitted infection caused by a fastidious gram-negative coccobacillus, H. ducreyi. REF: page 916 OBJ: Level 1 - Recall

2. All of the following additional patient history questions will help narrow the search for the pathogen EXCEPT: a. Does the patient have a history of previous gastrointestinal symptoms? b. Did the patient eat any hot food? c. Does the patient have an underlying illness? d. Is the patient taking any medication?

ANS: B Chronic inflammation, immunosuppression, and medications may themselves be causes for diarrhea. A patient's diarrhea may not be caused by an infection. REF: page 837 OBJ: Level 1 - Recall

32. Material from an intestinal abscess produces gray colonies with a brown color in the area around the colonies on a BBE plate incubated anaerobically. There is also a dark precipitate in the medium in the areas of heavy growth. A Gram stain of the colonies reveals gram-negative coccobacilli. What is the presumptive identification of this organism? a. Bacteroides vulgatus b. B. fragilis c. B. pneumoniae d. B. denticola

ANS: B Colonies of the B. fragilis group on BBE agar are gray and a minimum of 1 mm in diameter. The originally light-yellow medium turns brown in the area around the colonies. A dark precipitate in the medium around the areas of heavy growth is suggestive of the species B. fragilis, although some strains of B. ovatus also cause stippling. OBJ: Level 3: Synthesis

Material from an intestinal abscess produces gray colonies with a brown color in the area around the colonies on a BBE plate incubated anaerobically. There is also a dark precipitate in the medium in the areas of heavy growth. A Gram stain of the colonies reveals gram-negative coccobacilli. What is the presumptive identification of this organism? A. Bacteroides vulgatus B. B. fragilis C. B. pneumoniae D. B. denticola

ANS: B Colonies of the B. fragilis group on BBE agar are gray and a minimum of 1 mm in diameter. The originally light-yellow medium turns brown in the area around the colonies. A dark precipitate in the medium around the areas of heavy growth is suggestive of the species B. fragilis, although some strains of B. ovatus also cause stippling.

13. What are the two most frequently identified bacterial causes of community-acquired sinusitis? a. Staphylococcus aureus and Escherichia coli b. Streptococcus pneumoniae and Haemophilus influenzae c. S. pneumoniae and Mycoplasma pneumoniae d. H. influenzae and Neisseria meningitidis

ANS: B Common viruses causing acute sinusitis include rhinovirus, parainfluenzae, and influenza viruses. S. pneumoniae and H. influenzae are the bacterial pathogens identified most frequently in community-acquired infections. REF: page 780 OBJ: Level 1 - Recall

17. What organisms are most frequently isolated from cultures of individuals with otitis media? a. Staphylococcus aureus and Escherichia coli b. Streptococcus pneumoniae and Haemophilus influenzae c. S. pneumoniae and Mycoplasma pneumoniae d. H. influenzae and Neisseria meningitidis

ANS: B Considering the similarities in their pathogenesis, it is not surprising that the same group of pathogens is involved in both acute otitis media and acute sinusitis. S. pneumoniae and H. influenzae account for more than 50% of the isolates from cases of acute otitis media. REF: page 782 OBJ: Level 1 - Recall

30. How long are conventional blood cultures held? a. 4 days b. 7 days c. 14 days d. 21 days

ANS: B Conventional blood culture bottles must be held for at least 7 days. They may be discarded after 7 days if growth is not observed. REF: page 878 OBJ: Level 1 -

8. What is erysipelas? a. Inflammation of hair follicle b. A deep form of cellulitis c. A synonym for furuncle d. A synonym for carbuncle

ANS: B Erysipelas is a deeper form of cellulitis that involves not only the superficial epidermis but also the underlying dermis and lymphatic channels. Erysipelas is characterized as a painful, indurated area of cellulitis with a raised, sharply demarcated border and a typical deep crimson hue. REF: page 813 OBJ: Level 1 - Recall

6. All of the following are reasons why institutionalized patients have more urinary tract infections (UTIs) than noninstitutionalized patients EXCEPT: a. General ill condition of institutionalize patients b. Less frequent emptying of the bladder c. Higher probability of urinary tract instrumentation d. Higher incidence of urinary tract anatomic or functional abnormalities.

ANS: B Hospitalized patients and those residing in long-term care facilities develop UTIs more often than outpatients. The generally ill condition of the institutionalized population, higher probability of urinary tract instrumentation, and higher incidence of genitourinary tract anatomic or functional abnormalities are major contributors to this difference. REF: page 888 OBJ: Level 1 - Recall

2. What organism is most often responsible for impetigo? a. Staphylococcus epidermidis b. Streptococcus pyogenes c. Enterococcus faecalis d. Streptococcus agalactiae

ANS: B Impetigo is a common pyoderma often caused by group A streptococci (Streptococcus pyogenes). REF: page 812 OBJ: Level 1 - Recall

26. If a patient with a bacteremia is receiving antibiotics but not responding to treatment, how does the physician find out if another organism is present in the blood, causing the problem? a. Redraw the blood cultures. b. Redraw the blood cultures using an antibiotic removal device (ARD). c. Switch the patient to another antibiotic that will resolve the clinical symptoms. d. Perform hemodialysis to remove the organisms from the patient's blood.

ANS: B In specimens from patients receiving clinical amounts of -lactam antimicrobial agents, penicillinase may be added to the medium to inactivate these agents. Some commercially available automated blood culture systems have blood culture bottles containing ARD, a resin that nonspecifically absorbs any antimicrobial agent present in the patient's blood. REF: pages 877-878 OBJ: Level 2 - Interpretation

Question 11 If a patient with a bacteremia is receiving appropriate antimicrobial therapy for a known infection but is not responding to treatment, how does the physician find out if another organism is causing the problem? A. Redraw the blood cultures. B. Redraw the blood cultures using an antimicrobial removal device. C. Switch the patient to another agent that will resolve the clinical symptoms. D. Perform hemodialysis to remove the organisms from the patient's blood.

ANS: B In specimens from patients receiving β-lactam antimicrobial agents, penicillinase may be added to the medium to inactivate these agents. Some commercially available automated blood culture systems have blood culture bottles containing an antimicrobial removal device, a resin that nonspecifically absorbs any antimicrobial agent present in the patient's blood specimen.

25. The blood culture draw of three sets of blood culture specimens taken at 1-hour intervals within the first 24 hours is recommended to diagnose which of the following conditions? a. Meningitis b. Subacute bacterial endocarditis c. Pneumonia d. Peritonitis

ANS: B In subacute bacterial endocarditis, three sets of blood culture specimens taken at 1-hour intervals within the first 24 hours are recommended. REF: page 877 OBJ: Level 1 -

22. A farmer is bitten by a raccoon. He takes the usual precautions and washes the wound with soap and water, and then puts a bandage on it. A couple of days later, he begins to feel tired, has an upset stomach, and the wound is painful. About 2 days after noticing the symptoms, the farmer begins to feel agitated. He has a seizure and hallucinations. What condition matches the farmer's symptoms and history? a. West Nile virus b. Rabies c. Colorado tick fever d. Lassa fever

ANS: B Infection with rabies occurs following bites from infected animals, such as skunks, raccoons, bats, and foxes, as well as domesticated animals, such as dogs. Initial symptoms include fatigue, gastrointestinal symptoms, and pain at the bite wound. Rabies can present as acute encephalitis indistinguishable from other viral encephalitides or with the classic syndrome of agitation, emotional liability, seizures, and hallucinations (furious rabies). REF: page 864 OBJ: Level 3 - Synthesis

Question 9 A farmer is bitten by a raccoon. He washes the wound with soap and water and then puts a dressing on it. A couple of days later, he begins to feel tired and the wound is painful. About 2 days later, the farmer begins to feel agitated. He has a seizure and hallucinations. What condition matches the farmer's symptoms and history? A. WNV B. Rabies C. Colorado tick fever D. Lassa fever

ANS: B Infection with rabies occurs following bites from infected animals, such as skunks, raccoons, bats, and foxes, as well as domesticated animals, such as cats and dogs. Initial symptoms include fatigue, gastrointestinal symptoms, and pain at the bite wound. Rabies can present as acute encephalitis indistinguishable from other viral encephalitides or with the classic syndrome of agitation, emotional liability, seizures, and hallucinations.

2. If a patient has a throat culture done and the culture reveals the presence of a-hemolytic colonies, what does this indicate? a. These organisms are pathogenic and must be treated. b. These organisms are normally found in the pharynx and are normal. c. The patient is suffering from a viral pharyngitis. d. The patient has mouth ulcers that require antiviral treatment.

ANS: B Isolation of a-hemolytic colonies from a pharyngeal culture from a patient with pharyngitis arouses little clinical interest, because a-hemolytic streptococci are normal florae in the oropharynx. REF: page 774 OBJ: Level 2 - Interpretation

Question 15 Separate venipunctures were performed to collect three sets of blood cultures from a patient with an artificial heart valve. The first and third sets grew a gram-positive pleomorphic rod in 1 of 2 bottles while the second set had no growth in either bottle. What is the most likely explanation for these findings? A. The patient probably has an infection with Clostridium spp. B. The blood cultures were contaminated with skin biota. C. The blood cultures were probably contaminated in the laboratory. D. The patient probably has an infection with Bacillus spp.

ANS: B It is important to remember that even though antiseptic technique is used in the collection of blood, somewhere between 1% and 3% of blood cultures become contaminated with organisms such as coagulase-negative staphylococci, Corynebacterium spp., Bacillus spp. (not B. anthracis), alpha-hemolytic streptococci, and Propionibacterium acnes, which are ordinarily skin colonizers, resulting in pseudobacteremia.

17. What organism causes the Buruli ulcer? a. Streptococcus agalactiae b. Mycobacterium ulcerans c. Corynebacterium jejuni d. Mycobacterium leprae

ANS: B M. ulcerans infection usually occurs as a single, painless ulcer with undermined edges (the so- called Buruli ulcer of the tropics). REF: page 819 OBJ: Level 1 - Recall

36. How does Staphylococcus aureus acquire resistance to methicillin? a. An enzyme alteration b. Mobile DNA element c. Frameshift mutation d. RNA porin

ANS: B Methicillin-resistant S. aureus (MRSA) emerged soon after its introduction into clinical medicine in the 1960s and now exemplifies the acquisition of a new target by a pathogen to solve exposure to the toxic effects of the antibiotic. S. aureus solved the antimicrobial activity of methicillin exposure by acquisition of a mobile DNA element carrying a staphylococcal cassette chromosome mec (SCCmec), which confers resistance to methicillin. OBJ: Level 1: Recall

10. What type of meningitis is usually uncomplicated and resolves in 2 to 7 days? a. Septic meningitis b. Enteroviral c. Bacterial d. Meningococcal

ANS: B Most cases of enteroviral meningitis are uncomplicated, with signs and symptoms resolving in 2 to 7 days. REF: page 860 OBJ: Level 2 - Interpretation

17. A teenager and her friends go to the lake and spend the day swimming and picnicking. Later that evening, she starts to feel sick. She complains of a headache and general malaise. The next morning, she is very ill and is rushed to the emergency department. Many neurologic changes are noted. Despite the staff's best efforts, the teenager dies. Autopsy reveals the presence of small protozoans in her brain tissue. What is the most probable organism that caused her death? a. Acanthamoeba spp. b. Naegleria fowleri c. Balamuthia mandrillaris d. Angiostrongylus cantonensis

ANS: B N. fowleri can cause a rapidly progressive and almost always fatal primary meningoencephalitis. It is found in warm freshwater and moist soil. Most cases of infection have been associated with swimming in warm natural bodies of water. Acanthamoeba spp. and B. mandrillaris usually cause granulomatous amebic encephalitis with a more insidious onset. REF: page 862 OBJ: Level 3 - Synthesis

26. What type of pneumonia has been associated with Staphylococcus aureus that produces Panton- Valentine leukocidin? a. Methicillin-resistant pneumonia b. Necrotizing pneumonia c. Bacterial d. Viral

ANS: B Necrotizing pneumonia with pulmonary hemorrhage has been associated with S. aureus isolates that produce Panton-Valentine leukocidin. REF: page 792 OBJ: Level 1 - Recall

30. Nosocomial pneumonia can be caused by all of the following EXCEPT: a. Pseudomonas aeruginosa b. Streptococcus pneumoniae c. Acinetobacter baumannii d. Methicillin-resistant Staphylococcus aureus (MRSA)

ANS: B Patients with nosocomial pneumonia are at greater risk for colonization and infection with a wider spectrum of multidrug-resistant bacterial pathogens, such as Pseudomonas aeruginosa, extended-spectrum beta-lactamase Klebsiella pneumoniae, Acinetobacter baumannii, and MRSA. REF: page 794 OBJ: Level 1 - Recall

19. The clinical syndrome of Rocky Mountain spotted fever can be confused with which of the following conditions? a. Lyme disease b. Atypical measles c. Syphilis d. Allergic reactions

ANS: B Petechia and purpura represent extravasation of blood out of blood vessels and into the skin and evolve commonly as a result of the cutaneous vasculitis. The clinical syndrome of Rocky Mountain spotted fever may be confused with atypical measles, meningococcemia, other bacterial sepsis, enteroviral infection, and leptospirosis. REF: page 821 OBJ: Level 2 - Interpretation

23. What is herpetic whitlow? a. Primary herpetic lesions of the genitals b. Primary herpetic lesions of the finger c. Primary herpetic lesions of the anus d. Primary herpetic lesions of the lip

ANS: B Primary herpetic lesions of the finger, called herpetic whitlow, can be caused by either herpes simplex virus 1 (HSV-1) or HSV-2. REF: page 826 OBJ: Level 1 - Recall

32. The primary mechanism of resistance to this antimicrobial class is modification by mutations encoding single amino acid changes in these targets. What antibiotic class is this? a. Macrolides b. Quinolones c. Peptidoglycans d. Aminoglycosides

ANS: B Quinolones target DNA gyrase and topoisomerase IV. The primary mechanism of resistance to this antimicrobial class is modification by mutations encoding single amino acid changes in these targets. Mutations are generally localized to the amino terminal domains of gyrA and par C, termed the quinolone resistance-determining region. OBJ: Level 1: Recall

19. What are two important factors that must be taken into consideration when transporting specimens for anaerobic culture? a. Making sure there is enough specimen in a tightly closed container b. Minimum exposure to oxygen and preventing drying out c. Minimum exposure to oxygen and making sure the specimen is transported in a tightly closed screw-cap container d. Drying out and proper nutrition

ANS: B Regardless of the type of specimen submitted for anaerobic bacteriology, it must be transported and processed as rapidly as possible and with minimum exposure to oxygen. Specimens are usually collected from a warm, moist environment that is low in oxygen. Thus, it is important to avoid "shocking" the anaerobes by exposing them to oxygen or permitting them to dry out. This requires the use of an anaerobic transport medium. OBJ: Level 1: Recall

In August, a 30-year-old man presents with an ulcer on his leg with swelling of the lymph nodes in the surrounding area. He reports taking numerous hikes in the woods behind is house hunting rabbits. He does not recall any animal bites. What disease should be considered in the differential diagnosis? A. Lyme disease B. Tularemia C. Brucellosis D. Rat bit fever

ANS: B Rodents such as rabbits are common reservoirs of Francisella tularensis, the causative agent of tularemia. Most cases occur following contact with rabbits, although ticks can transmit the disease. Ulceroglandular disease is the form of tularemia seen most commonly.

Question 2 What organism is a common cause of meningitis in neonates and infants up to 3 months of age? A. Streptococcus pneumoniae B. Streptococcus agalactiae C. Haemophilus influenzae D. Neisseria meningitidis

ANS: B S. agalactiae or group B Streptococcus is a gram-positive coccus that is often isolated from rectal or vaginal cultures of asymptomatic pregnant women. It is a common cause of meningitis in neonates and infants up to age 3 months.

6. What organism is a common cause of meningitis in neonates and infants up to 3 months of age and can be contracted by passing through the birth canal? a. Streptococcus pneumoniae b. S. agalactiae c. Haemophilus influenzae d. Neisseria meningitidis

ANS: B S. agalactiae or group B streptococcus is a gram-positive coccus that is often isolated from rectal or vaginal cultures of asymptomatic pregnant women. It is a common cause of meningitis in neonates and infants up to age 3 months. REF: page 858 OBJ: Level 2 - Interpretation

14. What diarrheal illness occurs when organisms invade through the bowel wall, cause bacteremia, and also cause a mesenteric lymphadenitis that may be confused with appendicitis? a. Diarrhea in which the mucosal surface is invaded b. Diarrhea in which the full bowel thickness is invaded c. Diarrhea caused by endotoxins d. Diarrhea caused by enterotoxins

ANS: B Salmonella typhi and Yersinia enterocolitica organisms can invade through the bowel wall, cause bacteremia, and also cause a mesenteric lymphadenitis that may be confused with appendicitis. Diarrhea often is not the presenting symptom, and patients may actually have constipation at the onset of illness. REF: page 841 OBJ: Level 2 - Interpretation

13. Erythematous macules, petechiae, and purpura are all skin lesions of what condition? a. Hepatitis b. Meningococcemia c. Encephalitis d. Salmonella

ANS: B Similarly, the initial skin lesions of meningococcemia are erythematous macules, petechiae, and purpura located on the truck and extremities. REF: page 831 OBJ: Level 2 - Interpretation

24. What is the definitive method for collecting uncontaminated urine specimens? a. Catheterized specimen b. Suprapubic aspirate c. First morning specimen d. Voided midstream specimen

ANS: B Suprapubic aspiration is the definitive method for collecting uncontaminated urine specimens. REF: page 895 OBJ: Level 1 - Recall

14. Syphilitic involvement in the central nervous system (CNS) can take all of the following forms EXCEPT: a. Syphilitic meningitis b. Aseptic meningitis c. Gummatous neurosyphilis d. Parenchymatous neurosyphilis

ANS: B Syphilitic involvement of the CNS can take one of four forms: syphilitic meningitis, meningovascular syphilis, parenchymatous neurosyphilis, and gummatous neurosyphilis. REF: page 861 OBJ: Level 1 - Recall

6. What test is sufficient for a diagnosis of Neisseria gonorrhea in men? a. Culture b. Gram stain c. Enzyme immunoassay (EIA) d. Radioimmunoassay (RIA)

ANS: B The Gram stain is a sensitive, fast, and cheap tool for diagnosing gonorrhea in men. Gram stain of the penile exudates shows characteristic and diagnostic gram-negative intracellular diplococci in granulocytes. In symptomatic men, the Gram stain has a sensitivity of 90% to 95% and the specificity is over 95%. REF: page 907 OBJ: Level 1 - Recall

10. Penicillins, cephalosporins, monobactams, and carbapenems all have this ring in their structure that is responsible for inhibiting the transpeptidation reaction, resulting in bacterial lysis and cell death. a. Benzene b. -Lactam c. -Lactam d. Cephems

ANS: B The active moiety of -lactam antibiotics is the four-membered -lactam ring—a ring structure found in penicillins, cephalosporins, monobactams, and carbapenems. The four-membered ring represented by the structure labeled -lactam functions as a structural analogue of the normal substrate, and inhibits the transpeptidation reaction, resulting in bacterial lysis and cell death. OBJ: Level 1: Recall

15. All of the following antibiotics target the 50S ribosomal subunit to prevent mRNA translation in the bacteria, except a. macrolides. b. quinolones. c. oxazolidinones. d. streptogramins.

ANS: B The bacterial ribosome is a primary target of numerous antibiotics with some targeting the 30S ribosomal subunit (i.e., aminoglycosides, tetracyclines, glycylcycline) and others the 50S ribosomal subunit (i.e., macrolides, oxazolidinones, streptogramins). OBJ: Level 1: Recall

11. What disease does Clostridium tetani cause? a. Botulism b. Tetanus c. Food poisoning d. Myonecrosis

ANS: B The clinical manifestations of tetanus are attributed to the neurotoxin (tetanospasmin) produced by C. tetani.

20. The criteria used to determine the presence of a urinary tract infection (UTI) include all the following EXCEPT: a. Presence or absence of symptoms b. Patient history c. Predisposing factors d. The type of organism or organisms isolated

ANS: B The criteria that determine if a UTI is present must include the presence or absence of symptoms, predisposing factors, the patient population, and the type of organism or organisms isolated. REF: page 894 OBJ: Level 1 - Recall

6. Both gram-positive and gram-negative bacteria have an inner cytoplasmic membrane that is composed of a. nucleotides. b. phospholipids and proteins. c. cholesterol and carbohydrates. d. lipopolysaccharides.

ANS: B The cytoplasmic membrane, composed of phospholipids and proteins, surrounds the cytoplasm, acts as an osmotic barrier, and is the location of the electron transport chain responsible for energy production. OBJ: Level 1: Recall

21. What is the most common complication of pertussis? a. Otitis media b. Pneumonia c. Acute sinusitis d. Streptococcal pharyngitis

ANS: B The most common complication of pertussis is the pneumonia that occurs in young children. REF: page 785 OBJ: Level 1 - Recall

19. All of the following organisms are common in pneumonia and typically produce a concurrent bacteremia EXCEPT: a. Enterobacter aerogenes b. Escherichia coli c. Pseudomonas aeruginosa d. Staphylococcus aureus

ANS: B The most common organisms in pneumonia that produce a concurrent bacteremia include S. pneumonia, H. influenzae, S. aureus, P. aeruginosa, and Enterobacter aerogenes. REF: page 874 OBJ: Level 1 -

12. All the following organisms invade the bowel mucosal surface to produce diarrhea EXCEPT: a. Salmonella spp. b. Vibrio cholerae c. Campylobacter spp. d. Shigella spp.

ANS: B The most common organisms that invade the bowel mucosal surface to produce diarrhea include Salmonella spp., Campylobacter spp., Shigella spp., some Escherichia coli, and Entamoeba histolytica. REF: page 841 OBJ: Level 1 - Recall

31. What is river blindness? a. Infection with Naegleria fowleri b. Infection with Onchocerca volvulus c. Infection with Strongyloides stercoralis d. Infection with Entamoeba histolytica

ANS: B The most important manifestation of onchocerciasis, or river blindness, is infiltration of the eye by microfilariae, which causes visual disturbances and blindness. REF: page 828 OBJ: Level 1 - Recall

22. What organ is colonized in a patient that carries Salmonella typhi? a. Colon b. Gallbladder c. Rectum d. Small intestine

ANS: B The organism can frequently be recovered from both blood and stool cultures. Appropriate antibiotic use results in clinical improvement; however, stool cultures often remain positive, which can serve as a source of infection for other individuals. Some patients can also develop chronic colonization of their gallbladder and biliary tree, leading to persistent shedding of the organism and infections in multiple other people (the classic "Typhoid Mary" case). REF: page 843 OBJ: Level 1 - Recall

14. Many women who have bacterial vaginosis (BV) complain of a fishy odor from vaginal secretions. What causes the odor? a. Carbolic acid b. Amines c. Urea d. Alcohols

ANS: B Women with BV complain of a fishlike odor associated with the vagina. Bacterial vaginosis occurs when the lactic acid-producing lactobacilli, the most common group of bacteria in the healthy vagina, decrease in numbers. This causes an increase in the pH of the vagina, which allows Prevotella spp., Gardenerella vaginalis, and Mycoplasma hominis to increase greatly in number. These bacteria degrade proteins in the vagina to form amines to create the foul-smelling amines cadaverine, putrescine, and triethylamine. REF: page 909 OBJ: Level 1 - Recall

A gram-positive spore-forming bacillus growing on sheep-blood agar anaerobically produces a double zone of beta hemolysis and is positive for lecithinase. What is the presumptive identification? A. Bacteroides ureolyticus B. Bacteriodes fragilis C. Clostridium perfringens D. Clostridium difficile

ANS: C

A new Internal Medicine Resident comes to the Micro Lab to discuss the fact that some bacterial isolates do not have in vitro susceptibility testing performed, even when they are isolated in pure culture from clinically important sites. Which of the following organisms would you tell him/her would not be routinely tested? A. E. coli B. S. pyogenes C. P. mirabilis D. S. aureus

ANS: C

All of the following include cell wall synthesis inhibitors except for: A. cephalosporins. B. Glycopeptides C. rifampin D. carbapenums

ANS: C

If a stool specimen is sent to the laboratory to rule out Clostridium difficile, what media should the microbiologist use and what is the appearance of this organism on this medium? A. BBE: colonies turn black B. Brucella agar: red pigmented colonies C. CCFA: yellow, ground glass colonies D. CNA;double zone hemolytic colonies

ANS: C

Question 10 A fecal isolate identified as E. coli produces clear colonies on MacConkey agar with sorbitol. You should suspect A. Shigella sp. B. Enterotoxigenic E. coli. C. Enterohemorrhagic E. coli. D. The identification is incorrect.

ANS: C

Question 11 Bacteremia with this organism often leads to endocarditis, osteomyelitis, septic arthritis, hepatic abscess, or pyomyositis. A. Streptococcus pneumoniae B. Escherichia coli C. Staphylococcus aureus D. Pseudomonas aeruginosa

ANS: C

Question 13 What diarrheal pathogen can produce a disease that can lead to hemolytic-uremic syndrome? A. Enteropathogenic E. coli (EPEC) B. Enteroinvasive E. coli (EIEC) C. Enterohemorrhagic Escherichia coli (EHEC) D. Enterotoxigenic E. coli (ETEC)

ANS: C

Question 15 What virus causes community-wide seasonal outbreaks of bronchiolitis in infants? A. Rhinovirus B. Parainfluenza virus C. Respiratory syncytial virus D. Influenzae virus

ANS: C

Question 17 The most common cause of community-acquired bacteremia is: A. E. coli B. Pseudomonas aeruginosa C. Streptococcus pneumoniae D. Staphylococcus aureus

ANS: C

Question 27 __________ produces a brick-red fluorescence when viewed under the ultraviolet light. A. C. difficile B. Veillonella C. Porphyromonas spp. D. Fusobacterium spp.

ANS: C

Question 33 A common cause of eumycetoma: A. Actinomyces sp. B. Fonsecaea sp. C. Madurella sp. D. Candida albicans

ANS: C

Question 4 What common organism invades the full thickness of the bowel with lymphatic spread? A. Vibrio cholerae B. Campylobacter jejuni C. Salmonella typhi D. Aeromonas spp.

ANS: C

Question 40 All the following organisms invade the bowel mucosal surface to produce diarrhea, except A. Campylobacter spp. B. Shigella spp. C. Vibrio cholerae. D. Salmonella spp.

ANS: C

Question 6 E. coli is isolated from the spinal fluid of a 3-day-old infant. What is the most likely source of the bacterium? LO3; Level 1 A. Contact from humans B. Breast milk C. Birth canal D. Formula

ANS: C

Question 6 How is acute bronchitis differentiated from acute pneumonia? A. The amount of mucus secretion produced by the lower respiratory tract B. The involvement of the bronchial tree with the infectious process C. The degree and extent of involvement of the lower respiratory tract with the infectious process D. The degree of obstruction of the alveoli with the purulent secretions

ANS: C

Question 8 A CSF specimen was sent to the laboratory for analysis. A glucose, protein, and cell count were performed. Based on the following results, what would be the probable cause? LO8; Level 3 Analyte Results : Glucose- 50 mg/dL Protein- 100 mg/dL Leukocytes- 80 cells/mm 3 mononuclear A. Bacterial meningitis B. Fungal meningitis C. Viral meningitis D. Parasitic meningitis

ANS: C

Question 9 All of the following organisms commonly cause meningitis, except (LO 4; Level 1) A. Neisseria meningitidis. B. Streptococcus pneumoniae. C. Pseudomonas aeruginosa. D. Haemophilus influenzae.

ANS: C

When activating a hydrogen and carbon dioxide generator system used for creating an anaerobic atmosphere, which of the following is an indication that the catalyst and generator envelope are functioning properly? A. A decrease in temperature of the jar B. Bubble formation on the surface of the plates C. A change in color of the methylene blue indicator D. The formation of a visible cloud of gas

ANS: C

When using the rapid chromogenic cephalosporin method for the detection of beta-lactamase production by an organism, a positive test is indicated by the color: A. yellow B. green C. red D. blue

ANS: C

Which of the following anaerobes is inhibited by sodium polyanethol sulfonate (SPS)? A. Bacteroides fragilis B. Propionibacterium acnes C. Peptostreptococcus anaerobius D. Veillonella parvula

ANS: C

Which of the following statements is true regarding onchocerciasis? A. The adult worm is present in blood B. The microfilariae are in blood during the late evening hours C. The diagnostic test of choice is the skin snip D. The parasite resides in the deep lymphatics

ANS: C

22. Acquired mechanisms of resistance are those that a. are passed on from one bacteria to the next using pili. b. are the result of a frameshift mutation in chromosomal DNA. c. result from acquisition of DNA by acquisition of extrachromosomal DNA. d. passed on from generation to generation.

ANS: C Acquired mechanisms of resistance are those that result from the acquisition of DNA by transformation and recombination or by acquisition of extrachromosomal DNA and are transmitted horizontally. The latter includes acquisition of plasmids and transposons capable of disseminating resistant determinants. OBJ: Level 1: Recall

15. An immunosuppressed patient notices sinus tracts that are draining pus. He also notices that there appear to be small, hard "nuggets" in the pus. What disease is he most likely suffering from? a. Gas gangrene b. Pseudomembranous colitis c. Actinomycosis d. Myonecrosis

ANS: C Actinomycosis is a chronic, granulomatous, infectious disease characterized by the development of sinus tracts and fistulae, which erupt to the surface and drain pus containing sulfur granules (small colonies of bacteria). OBJ: Level 3: Synthesis

An immunosuppressed patient notices sinus tracts that are draining pus. He also notices that there appear to be small, hard "nuggets" in the pus. What disease is he most likely suffering from? A. Gas gangrene B. Pseudomembranous colitis C. Actinomycosis D. Myonecrosis

ANS: C Actinomycosis is a chronic, granulomatous, infectious disease characterized by the development of sinus tracts and fistulae, which erupt to the surface and drain pus containing sulfur granules (small colonies of bacteria).

14. Acute sinusitis usually occurs as a complication of: a. Bacterial pneumonia b. Viral pneumonia c. Common cold d. Streptococcal pharyngitis

ANS: C Acute sinusitis is usually a complication of common colds or other viral infections of the upper respiratory tract. REF: page 780 OBJ: Level 1 - Recall

7. A young woman goes to her doctor complaining of dysuria, frequency, urgency, and suprapubic pain. A urinalysis shows hematuria, positive protein, positive leukocyte esterase, and a positive nitrite. What is a probable diagnosis? a. Pyelonephritis b. Bacteremia c. Urinary tract infection (UTI) d. Septicemia

ANS: C Adults with uncomplicated lower UTIs limited to the urethra or bladder present primarily with dysuria, often in combination with frequency, urgency, suprapubic pain, and hematuria. Each episode of uncomplicated UTI in women is usually associated with 1 week of symptoms. REF: page 889 OBJ: Level 3 - Synthesis

20. What organism, which usually causes respiratory infections, causes maculopapular and vesicular rashes, urticaria, and immunologically mediated erythema nodosum and erythema multiform? a. Streptococcus pneumoniae b. Klebsiella pneumoniae c. Mycoplasma pneumoniae d. Haemophilus influenzae

ANS: C Although a primary pathogen of the respiratory tract, M. pneumoniae can cause maculopapular and vesicular rashes, urticaria, and immunologically mediated erythema nodosum and erythema multiforme. REF: page 821 OBJ: Level 2 - Interpretation

11. Common arborviruses that cause meningitis include all the following EXCEPT: a. St. Louis encephalitis virus b. La Cross virus c. Venezuelan equine encephalitis d. West Nile virus

ANS: C Although several of these viruses cause encephalitis, aseptic meningitis and meningoencephalitis can also occur. The common arboviruses causing aseptic meningitis include St. Louis encephalitis virus, La Crosse virus, eastern and western equine encephalitis virus, and West Nile virus. REF: page 860 OBJ: Level 1 - Recall

3. How is diarrhea usually contracted? a. By air b. By blood c. By contaminated food or water d. By respiratory droplet

ANS: C Although there are exceptions, diarrheal pathogens are usually acquired by ingesting a contaminated food or beverage. REF: page 837 OBJ: Level 1 - Recall

16. These antibiotics are cationic carbohydrate-containing molecules, and their positive charge provides the basis for their interaction with the 30S ribosomal subunit. What class of antibiotic are these? a. Sulfamethoxazole b. Trimethoprim c. Aminoglycosides d. Peptidoglycans

ANS: C Aminoglycosides are cationic carbohydrate-containing molecules, and their positive charge provides the basis for their interaction with a specific region in the 30S ribosomal subunit. Binding of the aminoglycosides to the 30S subunit prevents the docking of aminoacyl-tRNA, resulting in mistranslation and subsequent production of aberrant proteins. The incorporation of aberrant proteins into the cell wall also results in cell leakage and enhanced cellular penetration of additional antibiotic. OBJ: Level 1: Recall

25. What additive can maintain urine sample integrity for up to 48 hours at room temperature? a. Sodium citrate b. Calcium citrate c. Sodium borate d. Ethylenediamine tetraacetic acid (EDTA)

ANS: C An example of a urine sample additive is sodium borate, which maintains sample integrity for up to 48 hours at room temperature. Sodium borate also helps prevent overgrowth without causing toxicity to existing pathogens. REF: page 895 OBJ: Level 1 - Recall

18. Which of the following bacteria is most likely the cause of tooth abscesses? a. Bacteroides fragilis b. Porphyromonas asaccharolytica c. P. gingivalis d. Mobiluncus

ANS: C Anaerobic gram-negative bacilli are frequently found in mixed infections, causing abscesses and sepsis. B. fragilis often is isolated from soft-tissue infection. P. asaccharolytica is widely distributed in human tissues and fluids, whereas P. gingivalis and P. endodontalis are associated primarily with oral infections. OBJ: Level 3: Synthesis

3. Which of the following public health issues is uniting scientists from across the world to develop strategies to address it? a. Reclassifying bacteria according to their genomes b. The shortage of low toxicity antifungal drugs c. Antibiotic resistance d. Emerging pathogens

ANS: C Antibiotic resistance emerged soon after the discovery of antibiotics and is associated with the overuse of antimicrobial agents. Although antibiotics allow the medical community to make great strides in human health and welfare, their use also causes selective pressure, allowing only the fittest and less susceptible bacterial populations to thrive. Antibiotic resistance and its associated clinical failure is an issue of public health concern that is uniting scientists from across the world to develop strategies to address it. OBJ: Level 1: Recall

3. Bacteremias can be classified by all of the following schemes EXCEPT: a. Microbiology b. Acquisition c. Pathogenesis d. Duration

ANS: C Bacteremias can be classified by microbiology, acquisition, and duration. REF: page 871 OBJ: Level 1 -

19. Why are there so many cases of genital herpes in the United States? a. Condoms cannot prevent spread. b. No protection is available. c. Lesions shed when asymptomatic. d. Lesions shed when symptomatic.

ANS: C Because herpes simplex virus 2 (HSV-2) lesions are often painful, they would seem to deter sexual activity. Even so, many patients at least know to use barrier contraception when there is any sign of ulceration. What many patients with genital herpes may not know is that they shed virus even in the absence of symptoms. Studies indicate that patients are infective up to 30% of their symptom-free days. REF: page 917 OBJ: Level 1 - Recall

11. Because the urethra is shorter in women, bacteria are easily introduced into the bladder by: a. Fecal contamination b. Vaginal contamination c. Sexual intercourse d. Poor personal hygiene

ANS: C Because of the shorter urethra in women, bacteria are easily introduced into the bladder by sexual intercourse. REF: page 891 OBJ: Level 1 - Recall

36. How does Clostridium difficile produce pseudomembranous colitis and antibiotic-associated diarrhea? a. Endotoxin b. Hyaluronidase c. Toxin A and toxin B (exotoxins) d. Protease

ANS: C C. difficile, an anaerobic gram-positive rod, causes pseudomembranous colitis and antibiotic-associated diarrhea. These diseases typically occur in hospitalized patients who are receiving antibiotics or other chemotherapeutic agents that alter bowel flora. The organism produces two exotoxins, toxins A and B, which are involved in pathogenesis. OBJ: Level 2: Interpretation

33. What organism grows best at 42 C and in a reduced oxygen atmosphere (5% to 10%)? a. Shigella sonnei b. Clostridium difficile c. Campylobacter jejuni d. Escherichia coli

ANS: C C. jejuni grows best at 42 C and in an atmosphere of reduced oxygen content (5% to 10%), making them microaerophilic organisms.

9. What disease does Clostridium perfringens cause? a. Botulism b. Tetanus c. Food poisoning d. Toxic shock syndrome

ANS: C C. perfringens is associated with two types of food poisoning: type A, a relatively mild and self-limiting GI tract illness, and type C, a more serious but rarely seen GI tract disease. C. perfringens foodborne disease usually follows ingestion of enterotoxin-producing strains in contaminated food. OBJ: Level 1: Recall

28. What size calibrated loops should be used to ensure accurate quantitation of organisms? a. 0.001 mL b. 0.01 mL c. 0.1 mL d. 1.0 mL

ANS: C Calibrated loops of 0.01 mL should be used, not 0.001 mL (1 μL) loops, because quantitation is difficult to obtain with a low inoculum. REF: page 897 OBJ: Level 1 - Recall

17. What is one factor that may contribute to the incidence of candiduria in hospitalized patients? a. Poor personal hygiene b. Contaminated instruments c. Increased use of broad-spectrum antibiotics d. Increased use of multidrug regimens in hospitalized patients

ANS: C Candiduria is rare in healthy adults. However, it is commonly seen in hospitalized patients. As many as 10% of patients in tertiary care facilities have Candida in their urine. This is because of several factors, including sicker patients, increasing incidence of urinary instrumentation, and increasing use of broad-spectrum antibiotics. REF: page 892 OBJ: Level 1 - Recall

9. What is the most infamous type of myonecrosis? a. Tetanus b. Flesh-eating Streptococcus c. Gas gangrene d. Ebola hemorrhage

ANS: C Clostridial myonecrosis, also known as gas gangrene, is the most infamous type of myonecrosis and is caused by histotoxic clostridia, which include Clostridium septicum, C. perfringens, C. novyi, C. histolyticum, and C. sordellii. REF: page 815 OBJ: Level 1 - Recall

27. What usually causes community-acquired pneumonias in children during the winter months? a. Haemophilus influenzae b. Streptococcus pneumoniae c. Viral pathogens d. Legionella spp.

ANS: C Community-acquired pneumonias in children are usually attributable to viral pathogens that cause respiratory tract infections in the community during the winter months. REF: page 791 OBJ: Level 1 - Recall

11. Nonculture methods available for detecting Chlamydia include all the following EXCEPT: a. Enzyme immunoassay (EIA) b. Polymerase chain reaction (PCR) c. Fluorescence polarization immunoassay (FPIA) d. Ligase chain reaction (LCR)

ANS: C Culture can be laborious and expensive. A wide variety of nonculture methods are also available for the detection of Chlamydia trachomatis, such as EIA, PCR, and LCR. All nonculture methods detect C. trachomatis antigen. OBJ: Level 1 - Recall

24. How long are anaerobic cultures routinely held in the laboratory? a. 1 to 2 days b. 3 to 4 days c. 5 to 7 days d. 7 to 9 days

ANS: C Cultures are routinely held 5 to 7 days to allow growth of particularly slow-growing anaerobes and up to 3 weeks whenever Actinomyces spp. are suspected. OBJ: Level 1: Recall

What happens in the later stages of toxic shock syndrome as a result of the production of toxic shock syndrome toxin-1? A. Bruising B. Disseminated intravascular coagulation C. Desquamation D. Bacteremia

ANS: C Cutaneous desquamation occurs in toxic shock syndrome (TSS) because of the production of staphylococcal exotoxins. TSS clinical presentations include a diffuse sunburn-like erythroderma appearing early in the course and accompanied by fever, hypotension, and evidence of multiorgan dysfunction. Desquamation of skin, especially on the palms and soles, occurs during the convalescent stage of the illness.

17. Which of the following is an opportunistic virus that can lead to diarrhea in an immunocompromised host? a. Rubella b. Parvo B19 c. Cytomegalovirus d. Filovirus

ANS: C Cytomegalovirus (CMV) is an opportunistic virus that can lead to diarrhea. Typical symptoms consist of watery diarrhea, pain, and blood in the stool. Fever is often present. REF: page 842 OBJ: Level 1 - Recall

Question 16 Which of the following organisms is inhibited by the anticoagulant SPS? A. Enterobacter aerogenes B. Escherichia coli C. Peptostreptococcus anaerobius D. Streptococcus pyogenes

ANS: C Despite its usefulness in blood culture media, SPS inhibits the growth of certain organisms, notably Peptostreptococcus anaerobius, Neisseria gonorrhoeae, N. meningitidis, and Gardnerella vaginalis. If these organisms are suspected, 1.2% gelatin added to the blood culture bottle may help to neutralize the inhibitory effect of SPS.

Question 2 Gram-positive diplococci, with a halo, are seen on a STAT CSF taken from an adult who presented to the emergency department with high fever, still neck, and confusion. You should suspect: A. Neisseria meningitidis B. Klebsiella pneumoniae C. Streptococcus agalactiae D. Streptococcus pneumoniae

ANS: D

31. What is empyema? a. A collection of fluid in the lung resulting from the pathogenesis of bacterial pathogens b. A collection of fluid in the lung resulting from the pathogenesis of viral pathogens c. A collection of purulent fluid in the pleural space between the lung and the chest wall d. A collection of purulent fluid in the bronchii and alveoli

ANS: C Empyema is defined as a collection of purulent fluid in the pleural space between the lung and the chest wall. Although the accumulation of pleural fluid is fairly common in association with acute bacterial pneumonia, most such accumulations are sterile, only a small percentage of which qualify as empyemas. REF: page 797 OBJ: Level 1 - Recall

33. This type of resistance mechanism modifies the antibiotic targets and results in reduced affinity of antibiotics for their microbial targets. a. Cell wall inhibition b. Protein synthesis modification c. Enzyme alteration d. Frameshift mutation

ANS: C Enzymatic alterations of antibiotic targets result in reduced affinity of antibiotics for their microbial targets and are exemplified by erythromycin ribosomal methylase and by reprogramming of the peptidoglycan termini. OBJ: Level 1: Recall

A common cause of eumycetoma: A. Actinomyces sp. B. Candida albicans C. Madurella sp. D. Fonsecaea sp.

ANS: C Eumycetoma are fungal infections deep with the tissue that cause swelling and often sinus tracts that produce an exudate. These infections are typically caused by Madurella, Pseudallescheria boydii, and Aspergillus. Fonsecaea causes chromoblastomycosis. Certain bacteria can produce a similar disease called actinomycetoma.

15. All of the following are common fungal causes of central nervous system (CNS) infection EXCEPT: a. Cryptococcus neoformans b. Coccidioides immitis c. Candida albicans d. Histoplasma capsulatum

ANS: C Fungi are rare causes of CNS infections. The most common organisms in CNS fungal infections include C. neoformans, C. immitis, H. capsulatum, and Blastomyces dermatitidis. REF: page 861 OBJ: Level 1 - Recall

6. Besides antimicrobial therapy, how are most carbuncles treated? a. Teabags to draw the poison out b. Moist heat, then cold compresses c. Surgical drainage d. Squeezing to express the pus and necrotic tissues

ANS: C Furuncles usually can be managed by the application of moist heat and antimicrobial therapy. Surgical drainage is generally needed for most carbuncles. REF: page 814 OBJ: Level 1 - Recall

11. What is the mechanism of action of the glycopeptides (vancomycin and teicoplanin)? a. The glycopeptides inhibit folate synthesis and prevent the bacteria from using this as an energy source. b. The glycopeptides interfere with DNA replication and disrupt the protein synthesis operation. c. The glycopeptides bind to the substrate of the transpeptidation enzyme and disrupt the cell membrane construction. d. The glycopeptides interfere with transfer RNA production and disrupt the protein synthesis operation.

ANS: C Glycopeptides, such as vancomycin and the investigational drug teicoplanin, act by complexing the noncross-linked peptide strands of peptidoglycan units having the pentapeptidyl tails ending in D-ala-D-ala. This prevents their incorporation into the peptidoglycan chain by blocking the transpeptidation step. Glycopeptides bind to the substrate of the transpeptidation enzyme, and penicillins bind to the enzyme mediating the transpeptidation reaction. OBJ: Level 1: Recall

3. All of the following can contribute to reduced leukocyte chemotaxis in the renal medulla EXCEPT: a. High ammonia concentration b. Hyperosmolarity c. Reduced water reabsorption d. Sluggish blood flow

ANS: C However, conditions such as high ammonia concentration, hyperosmolarity, lowered pH, and sluggish blood flow in the renal medulla can contribute to reduced leukocyte chemotaxis and bactericidal activity of white blood cells, resulting in lowered infection resistance. REF: page 887 OBJ: Level 1 - Recall

30. What condition caused by diarrhea will trigger kidney failure, liver failure, myocardial infarction, and death? a. Metabolic alkalosis b. Metabolic acidosis c. Volume depletion d. Electrolyte imbalance

ANS: C However, there can be serious sequelae from diarrheal infections in some cases. Volume depletion from diarrhea has been associated with kidney failure, liver failure, myocardial infarctions, and death. REF: page 852 OBJ: Level 2 - Interpretation

18. Infection with what organism results in a chronic meningoencephalitis more commonly known as sleeping sickness? a. Gnathostoma spinigerum b. Baylisascaris procyonis c. Trypanosoma brucei gambiense d. Trypanosoma brucei rhodesiense

ANS: C Humans are infected by the bite of a tsetse fly. Trypanosoma brucei gambiense results in a chronic meningoencephalitis more commonly known as sleeping sickness. Central nervous system (CNS) infection with Trypanosoma brucei rhodesiense results in a more acute disease that often results in death. REF: page 863 OBJ: Level 2 - Interpretation

7. In gram-positive bacteria, this is substantially thicker and more multilayered than in gram-negative bacteria. a. Lipopolysaccharide b. Phospholipid c. Peptidoglycan d. Cholesterol

ANS: C In gram-positive bacteria, the peptidoglycan is substantially thicker and more multilayered than in gram-negative bacteria. OBJ: Level 1: Recall

14. What happens in the late stages of toxic shock syndrome as a result of the production of exotoxin F? a. Bruising b. Disseminated intravascular coagulation (DIC) c. Desquamation d. Bacteremia

ANS: C In toxic shock syndrome, cutaneous desquamation may occur in the late stage as a result of exotoxin F production by Staphylococcus aureus. A diffuse sunburn-like erythroderma appears early in the course and is accompanied by fever, hypotension, and evidence of multiorgan dysfunction. Desquamation of skin, especially on the palms and soles, occurs during the convalescent stage of the illness. REF: page 832 OBJ: Level 2 - Interpretation

12. What is the most common way for the renal parenchyma to become infected with gram-positive bacteria? a. Ascending route b. Descending route c. Hematogenous route d. Poor personal hygiene

ANS: C Infection of the renal parenchyma by many species of gram-positive bacteria (particularly in patients with staphylococcal bacteremia or endocarditis, mycobacterial infection, Candida infection, and other fungal infections) clearly occurs by the hematogenous route. Gram-negative infections rarely occur by the hematogenous route. REF: page 891 OBJ: Level 1 - Recall

Question 26 _____________________ is susceptible to sodium polyanetholsulphonate while other gram-positive anaerobic cocci are resistant. A. Staphylococcus asaccharolyticus B. Finegoldia magna C. Veillonella D. Peptostreptococcus anaerobius

ANS: D

19. Disease caused by which of the following organisms has fever, abdominal cramping, diarrhea, and stools with gross blood and pus? a. Staphylococcus aureus b. Clostridium difficile c. Campylobacter jejuni d. Bacillus cereus

ANS: C Infections with this organism usually result in a self-limited disease characterized by fever, abdominal cramping, and diarrhea. The incubation period is normally 2 to 5 days, but in some cases has extended up to 10 days. Diarrhea is often preceded by a period of febrile malaise with myalgias and abdominal pain. Stools may have gross blood and pus present. REF: page 842 OBJ: Level 2 - Interpretation

42. Integrons are a. circular structures present in bacteria that contain genes encoding proteins and RNA and have the capacity to self-replicate and portion into daughter cells during cellular division. b. DNA elements that encode transposition and excision function and can transpose from one place on the chromosome to another. c. genetic elements capable of integrating resistance genes (cassettes) by an integron-encoded, site-specific recombinase. d. DNA elements found in bacteria that carry genes only for the enzymes needed to promote their own transposition.

ANS: C Integrons are genetic elements and have the capacity of integrating resistance genes by an integron-encoded, site-specific recombinase. The integron in Tn21 does not code for its own mobilization but can be moved when transposition proteins are provided in trans; is bound by imperfect terminal inverted repeats; contains the aadA1-resistant determinant on a cassette. OBJ: Level 1: Recall

3. What should a microbiologist do if he or she finds a-hemolytic colonies on a properly collected sputum specimen on a patient suspected of having lobar pneumonia? a. Ignore the colonies because they are normal florae. b. Ignore the colonies because no known pathogens for pneumonia are a-hemolytic. c. Do a full workup to identify the organism. d. Suspect a bioterror agent, and send the isolate to a laboratory response network (LRN) reference laboratory.

ANS: C Isolation of an a-hemolytic colony from a properly collected sputum specimen or bronchial aspirate in the clinical setting of lobar pneumonia should prompt full identification of the organism and perhaps initiation of empirical therapy for possible pneumococcal infection. REF: page 774 OBJ: Level 2 - Interpretation

12. What organism mostly commonly causes gas gangrene? a. Clostridium difficile b. C. tetani c. C. perfringens d. C. botulinum

ANS: C Myonecrosis, or gas gangrene, usually occurs when organisms contaminate wounds, through either trauma or surgery. C. perfringens, C. histolyticum, C. septicum, C. novyi, and C. bifermentans are members of the histotoxic group and can cause myonecrosis. C. perfringens, however, is the most common cause. OBJ: Level 1: Recall

3. What is an obligate anaerobe? a. An organism that requires some oxygen but moderate concentrations of CO2 to live b. An organism that requires small amounts of oxygen and carbon dioxide to live c. An organism that grows only in the absence of molecular oxygen d. An organism that can live with very little oxygen

ANS: C Obligate anaerobes, which grow only in the absence of molecular oxygen, vary in their sensitivity to oxygen. They can be classified as moderate anaerobes and strict anaerobes. Oxygen kills obligate anaerobes. OBJ: Level 1: Recall

3. A college student is examined at the emergency department; he is disoriented with a fever, intense headache, stiff neck, vomiting, and sensitivity to light. His friends say that he has been sick for about 2 days and that his condition worsened over the last 3 hours. The physician does a complete blood count (CBC) and electrolytes. The electrolytes are normal, but the patient's white blood count (WBC) is 12,000 cells/L. What test should the doctor order next? a. Urine culture b. Stool culture c. Cerebrospinal fluid (CSF) Gram stain and culture d. Blood culture

ANS: C Patients with acute meningitis usually present with fever, headache, vomiting, photophobia, and altered mental status. REF: page 857 OBJ: Level 3 - Synthesis

20. What condition leads to most (75%) of the cases of bacteremia from intra-abdominal infections? a. Pleurisy b. Cholecystitis c. Peritonitis d. Irritable bowel syndrome

ANS: C Primary peritonitis, which frequently occurs in patients with cirrhosis, is associated with bacteremia in 75% of cases involving aerobic bacteria; common pathogens include Escherichia coli, Klebsiella pneumoniae, Streptococcus pneumoniae, and Enterococcus. REF: page 874 OBJ: Level 1 -

23. What virus causes community-wide seasonal outbreaks of bronchiolitis in infants? a. Rhinovirus b. Parainfluenza virus c. Respiratory syncytial virus (RSV) d. Influenzae virus

ANS: C RSV also causes community-wide seasonal outbreaks of bronchiolitis in infants. REF: page 786 OBJ: Level 1 - Recall

22. What is the specimen of choice for recovery of Bordetella pertussis? a. Dacron nasopharyngeal swabs b. Rayon nasopharyngeal swabs c. Calcium alginate nasopharyngeal swabs d. Cotton nasopharyngeal swabs

ANS: C Recovery of B. pertussis depends to a large extent on proper specimen collection and processing. Nasopharyngeal swabs using calcium alginate are preferred. REF: page 785 OBJ: Level 1 - Recall

28. What is ringworm? a. A parasitic skin infection b. A bacterial skin infection c. A fungal skin infection d. A viral skin infection

ANS: C Ringworm is another term often applied to these infections and reflects the tendency of some lesions to expand annularly. REF: page 811 OBJ: Level 1 - Recall

15. What virus is the leading cause of diarrhea in children younger than age 5? a. Enteric adenoviruses b. Astroviruses c. Rotavirus d. Calicivirus

ANS: C Rotaviruses are the major cause of diarrhea in children younger than age 5, causing an estimated 130 million episodes of illness worldwide each year. REF: page 841 OBJ: Level 1 - Recall

24. What causes rubeola? a. Calicivirus b. Herpesvirus c. Paramyxovirus d. Torovirus

ANS: C Rubeola (measles) is caused by a paramyxovirus and is spread by direct contact with respiratory secretions of infected persons. REF: page 823 OBJ: Level 1 - Recall

12. Bacteremia with this organism may lead to endocarditis, osteomyelitis, septic arthritis, hepatic abscess, or pyomyositis. a. Streptococcus pneumoniae b. Escherichia coli c. Staphylococcus aureus d. Pseudomonas aeruginosa

ANS: C S. aureus is particularly prone to cause metastatic infection or abscess formation as a consequence of bacteremia; S. aureus bacteremia may lead to endocarditis, osteomyelitis, septic arthritis, hepatic abscess, or pyomyositis. REF: page 874 OBJ: Level 2 - Interpretation

35. What is the most common causative agent of gas gangrene? a. Staphylococcus aureus b. Neisseria gonorrhoeae c. Clostridium perfringens d. Haemophilus influenzae

ANS: C Several common organisms are encountered in the microbiology laboratory. Infections caused by common single species, or by classic infectious agents, include C. perfringens gas gangrene, Streptococcus pneumoniae pneumonia, Staphylococcus aureus abscesses or pyodermas, H. influenzae tracheobronchitis or meningitis in infants, Nocardia spp. lung abscesses, and gonococcal urethritis. OBJ: Level 2: Interpretation

What is the most common causative agent of gas gangrene? A. Staphylococcus aureus B. Neisseria gonorrhoeae C. Clostridium perfringens D. Haemophilus influenzae

ANS: C Several common organisms are encountered in the microbiology laboratory. Infections caused by common single species, or by classic infectious agents, include C. perfringens gas gangrene, Streptococcus pneumoniae pneumonia, Staphylococcus aureus abscesses or pyodermas, H. influenzae tracheobronchitis or meningitis in infants, Nocardia spp. lung abscesses, and gonococcal urethritis.

29. How do the -lactamase inhibitors work? a. By structurally rearranging the -lactamase molecule so that it loses specificity for the -lactam antibiotic b. By competing with the antibiotic for porin sites on the outer membrane c. By acting as substrates for the -lactamase and reducing their effect on the antibiotic d. By acting as transport molecules to transport the antibiotic into the bacterial cell

ANS: C The -lactamase inhibitors are structural analogues of the -lactam antibiotics and function as substrates for -lactamase, thus reducing their effect on the -lactam antibiotic. OBJ: Level 1: Recall

37. This is one of the first resistance mechanisms identified and is a strategy that bacteria use successfully to survive the action of many classes of antibiotics. a. Frameshift mutation b. Plasmid DNA acquisition c. Acquisition of inactivating enzymes d. Impermeability to the cell wall

ANS: C The acquisition of enzymes that inactivate antibiotics directly is one of the first mechanisms of resistance identified in bacteria and is a strategy that bacteria use successfully to survive the action of many classes of antibiotics. Several of the best-studied classic examples are the enzymes that mediate hydrolysis of the -lactam ring of -lactam antibiotics. OBJ: Level 1: Recall

23. What toxin do Shigella spp. produce? a. Typhi b. Enterotoxin c. Shiga d. Campy

ANS: C The bacteria produce several toxins, one of which is the Shiga toxin, which can have cytotoxic, enterotoxic, and neurotoxic effects. REF: page 843 OBJ: Level 1 - Recall

29. In what type of specimen is the etiologic agent of acute prostatitis usually recovered? a. Voided midstream urine b. Suprapubic aspirate c. Straight catheterization d. All of the above

ANS: C The etiologic agent of acute prostatitis is usually recovered from catheterized specimens, which should be cultured in the same manner as for specimens from symptomatic men. REF: page 898 OBJ: Level 1 - Recall

7. What is the most common cause of death among patients with diarrhea? a. Sepsis b. Septic shock c. Dehydration d. Secondary bacterial infections

ANS: C The first step in the physical examination of a patient with a diarrheal illness is to determine the patient's state of hydration, as dehydration is the most common cause of death in patients with diarrhea. REF: page 839 OBJ: Level 1 - Recall

21. All of the following procedures should be performed on clinical specimens to recover anaerobic bacteria, except a. specimen plating on appropriate tubed and plated media. b. anaerobic incubation. c. Kinyoun stain. d. Gram stain.

ANS: C The following procedures should be performed on clinical specimens for the recovery of anaerobic bacteria: macroscopic examination of the specimen; preparation of Gram-stained smears for microscopic examination; inoculation of appropriate plated and tubed media, including media specifically designed for culturing anaerobes; and anaerobic incubation of inoculated media. OBJ: Level 1: Recall

3. A man has sex with a woman on Saturday night. On Wednesday he notices dysuria, pyuria, and a urethral discharge. He goes to his doctor who orders a Gram stain of the discharge. The results of the Gram stain show > 25 wbc/hpf, moderate gram-negative intracellular diplococci, and 3+ gram-negative diplococci. What is the mostly likely diagnosis? a. Syphilis b. Chlamydia c. Gonorrhea d. Bacterial vaginosis

ANS: C The incubation period for Neisseria gonorrhea from exposure to first symptoms is 2 to 7 days. In men, symptoms include urethral inflammation with dysuria, pyuria, and, in most cases, urethral discharge. The Gram stain is a sensitive, fast, and cheap tool for diagnosis of gonorrhea in men. Gram stain of the penile exudates shows characteristic and diagnostic gram-negative intracellular diplococci in granulocytes. In symptomatic men, the Gram stain has a sensitivity of 90% to 95% and the specificity is over 95%. REF: page 906 OBJ: Level 3 - Synthesis

15. What is the main symptom for primary syphilis? a. Purulent discharge b. Asymptomatic c. Chancre d. Genital warts

ANS: C The initial lesion of syphilis is called the chancre, and its appearance signals primary syphilis. REF: page 909 OBJ: Level 2 - Interpretation

19. These two classes of antibiotics allow initiation and mRNA translation to begin, but they act by inhibiting peptide elongation. a. Aminoglycosides and glycopeptidians b. Aminoglycosides and quinolones c. Macrolides and tetracyclines d. Macrolides and quinolones

ANS: C The macrolides and tetracyclines allow initiation and mRNA translation to begin, but they act by inhibiting peptide elongation. OBJ: Level 1: Recall

13. What common organism invades the full thickness of the bowel with lymphatic spread? a. Vibrio cholerae b. Campylobacter jejuni c. Salmonella typhi d. Aeromonas spp.

ANS: C The most common invasive enteric organisms are S. typhi and Yersinia enterocolitica. REF: page 841 OBJ: Level 2 - Interpretation

24. What are the most common bacteria isolated from nontraumatic brain abscesses? a. Staphylococcus b. Enteric gram-negative rods c. Streptococcus d. Clostridium

ANS: C The most common organism isolated from nontraumatic brain abscesses include aerobic, anaerobic, and microaerophilic streptococci. REF: page 864 OBJ: Level 1 - Recall

21. In what patient population is a colony count on a urine culture significant? a. Young, sexually active women with cystitis b. Elderly men with prostatitis c. Asymptomatic individuals with pyelonephritis d. Elderly women with candiduria

ANS: C The outcome of a urine culture must be evaluated together with other laboratory and clinical data; attempts to attach significance to the colony count should be restricted to the original patient population in which that significance was established. REF: page 894 OBJ: Level 2 - Interpretation

Question 6 Infection with what organism results in a chronic meningoencephalitis, more commonly known as sleeping sickness? A. Gnathostoma spinigerum B. Baylisascaris procyonis C. Trypanosoma brucei D. Trypanosoma cruzi

ANS: C Trypanosomes that infect humans include Trypanosoma brucei subsp. gambiense, Trypanosoma brucei subsp. rhodesiense, and Trypanosoma cruzi. The first two are found predominantly in Africa. Humans are infected by the bite of tsetse flies. T. brucei gambiense results in a more chronic and slowly progressing form of sleeping sickness compared to T. brucei rhodesiense, which has a more rapid and acute course. Both diseases are fatal if untreated.

26. A man and his family drive to the coast and have an oyster dinner. A couple of days later, the man arrives at the emergency department with a fever, bullous skin lesions, and diarrhea. He is extremely ill and the doctor questions whether he is septic. Blood and stool specimens are collected. The microbiology technician notices curved gram-negative rods on the stool Gram stain. What is the most probable organism causing this condition? a. Yersinia enterocolitica b. Cryptosporidium jejuni c. Vibrio vulnificus d. Vibrio cholerae

ANS: C V. vulnificus is the most virulent of all noncholera vibrios, causing an often fulminant illness characterized by sepsis and bullous skin lesions in patients with a recent ingestion of shellfish (i.e., raw oysters). This Vibrio sp. is part of the marine florae, making a common colonizer of a large percentage of oysters harvested in the warmer months. REF: page 844 OBJ: Level 3 - Synthesis

11. All the following are virulence factors that allow microorganisms to produce disease, EXCEPT: a. Adherence b. Toxin elaboration c. Mucus production d. Host evasion

ANS: C Virulence factors involved in disease-producing mechanisms, such as adherence, toxin elaboration, and host evasion, enable the microorganism to complete this process. REF: page 777 OBJ: Level 1 - Recall

7. What condition is characterized by lymphocytic pleocytosis in the cerebrospinal fluid (CSF) but a lack of identifiable organism after routine culture and Gram stain? a. Purulent meningitis b. Septic meningitis c. Aseptic meningitis d. Malignant meningitis

ANS: C Viruses are the most common cause of aseptic meningitis, a condition characterized by a lymphocytic pleocytosis in the CSF and lack of identifiable etiologic agent after routine stains and culture of the CSF. REF: page 859 OBJ: Level 2 - Interpretation

Question 3 What condition is characterized by lymphocytic pleocytosis in the CSF but a lack of identifiable organism after routine culture and Gram stain? A. Purulent meningitis B. Septic meningitis C. Aseptic meningitis D. Malignant meningitis

ANS: C Viruses are the most common cause of aseptic meningitis, a condition characterized by a lymphocytic pleocytosis in the CSF and lack of identifiable etiologic agent after routine stains and culture of the CSF.

29. What disk is used to presumptively identify Peptostreptococcus anaerobius? a. Bile b. Nitrate c. Sodium polyanethol sulfonate (SPS) d. Indole

ANS: C Whenever an anaerobic, gram-positive coccus is isolated, an SPS disk is used to presumptively identify P. anaerobius, which is susceptible to SPS. OBJ: Level 1: Recall

A very small, single-stranded DNA virus that causes a febrile illness with a bright red rash of the face and is called erythema infectiosum is : A. Rotavirus B. Adenovirus type 40 C. Coxsackie A virus D. Parvovirus B19

ANS: D

All of the following genera are anaerobic cocci that stain gram positive except: A. Peptococcus spp. B. Peptostreptococcus spp. C. Streptococcus spp. D. Veillonella spp.

ANS: D

Clavulanic acid is classified as a(n) A. aminoglycoside B. macrolide C. beta lactam D. beta lactamase inhibitor

ANS: D

Question 1 What type of meningitis is usually uncomplicated and resolves in 2 to 7 days? A. Meningococcal B. Bacterial C. Septic meningitis D. Enteroviral

ANS: D

Question 11 SITUATION: What is the most likely cause of the following CSF results? CSF glucose 20 mg/dL; CSF protein 200 mg/dL; CSF lactate 50 mg/dL (reference range 5-25 mg/dL) A. Viral meningitis B. Viral encephalitis C. Cryptococcal meningitis D. Acute bacterial meningitis

ANS: D

Question 13 Which of the following statements regarding routine microbiological examination of CSF is true? A. A Gram stain is performed on the CSF prior to concentration B. The Gram stain is positive in fewer than 40% of cases of acute bacterial meningitis C. India ink and acid fast stains are indicated if neutrophilic pleocytosis is present D. All CSF specimens should be cultured using sheep blood agar, chocolate agar, and supplemented broth

ANS: D

Question 14 A CSF sample from an 8-year-old child with a fever of unknown origin was tested for glucose, total protein, lactate, and IgG index. Glucose was 180 mg/dL, but all other results were within the reference range. The CSF WBC count was 9 × 106/L, and the RBC count was 10 × 106/L. The differential showed 50% lymphocytes, 35% monocytes, 10% macrophages, 3% neutrophils, and 2% neuroectodermal cells. What is the most likely cause of these results? A. Aseptic meningitis B. Traumatic tap C. Subarachnoid hemorrhage D. Hyperglycemia

ANS: D

Question 14 Most influenza epidemics and pandemics A. are due to influenza B virus. B. are due to influenza C virus. C. are due to parainfluenza viruses. D. follow a recombination event in causative agent's genome.

ANS: D

Question 15 A Gram -negative bacillus has been isolated from feces and the confirmed biochemical reactions fit those of Shigella. The organism does not agglutinate in Shigella antisera. What should be done next? A. test the organism with a new lot of antisera B. test with Vi antigen C. repeat the biochemical tests D. boil the organism and retest with the antisera.

ANS: D

Question 15 A patient receiving chemotherapy for leukemia has developed a fever causing the physician to request blood cultures times three. Each set of cultures grows an α-hemolytic streptococcal organism. What is the most likely explanation for these results? A. The blood cultures were contaminated with skin biota B. The patient probably has an infection with Bacillus spp C. The blood cultures were probably contaminated in the laboratory D. The patient probably has an infection with α-hemolytic strep.

ANS: D

Question 19 What underlying condition predisposes a person to a polymicrobial bacteremia? A. Burns B. Intravenous drug use C. Gastrointestinal tract sources D. All of the above

ANS: D

Question 13 Septi-Chek is which type of blood culture system? A. Continuous-monitoring blood culture system B. Lysis-centrifugation blood culture system C. Aerobic-anaerobic blood culture system D. Biphasic broth-slide system

ANS: D A broth-slide system was designed from the original biphasic blood culture medium culture bottle. Septi-Chek consists of a slide paddle containing chocolate, MacConkey, and malt extract agars attached to the top of a standard broth bottle. Once these bottles have been inoculated, they should be tipped daily or at least twice weekly to bathe the slide paddle with the broth culture medium.

16. What is a symptom for secondary syphilis? a. Chancre b. Purulent discharge c. Petechiae d. Perianal condylomata-lata

ANS: D A result of secondary syphilis is the appearance of condylomata-lata, which are mucoid, fleshy, wartlike growths. These lesions often occur in the perianal region but can occur in other moist regions of the body. REF: page 909 OBJ: Level 2 - Interpretation

23. Altered clinical laboratory values that may be indicative of bacteremia include all the following EXCEPT: a. Disseminated intravascular coagulation (DIC) b. Thrombocytopenia c. Coagulopathy d. Anemia

ANS: D Altered clinical laboratory values that may be indicative of bacteremia include the following: thrombocytopenia, leukocytosis or leukopenia, lactic acidosis, hypoglycemia or hyperglycemia, abnormal liver function tests, coagulopathy, DIC, and elevations in C-reactive protein, haptoglobin, and fibrinogen. REF: page 875 OBJ: Level 1 -

4. Mechanisms that mediate intrinsic antibiotic resistance include all the following, except a. cell wall impermeability. b. biofilm formation. c. expression of genes mediating inactivating enzymes. d. alternate biosynthetic pathways.

ANS: D Antibiotic resistance may be characterized as intrinsic and is an inherent genotypic characteristic of the microorganism disseminated vertically to progeny. Mechanisms that mediate intrinsic resistance to antibiotics include cell wall impermeability, efflux, biofilm formation, and the expression of genes producing inactivating enzymes. OBJ: Level 1: Recall

20. All of the following are important arboviruses EXCEPT: a. Alphaviruses (Venezuelan equine encephalitis viruses, eastern equine encephalitis, and western equine encephalitis) b. St. Louis encephalitis virus c. La Crosse virus d. Lassa fever virus

ANS: D Arboviruses (arthropod-borne viruses) are RNA viruses that demonstrate strong tropism for the central nervous system. These viruses are transmitted to humans by mosquitoes, ticks, or sandflies. Important arboviruses in the western hemisphere include members of the alphaviruses (eastern equine encephalitis, western equine encephalitis, and Venezuelan equine encephalitis viruses), flaviviruses (St. Louis encephalitis virus), bunyaviruses (La Crosse virus), and coltivirus (Colorado tick fever). REF: pages 860, 864 OBJ: Level 1 - Recall

Question 7 All of the following are important arboviruses, except A. Venezuelan equine encephalitis viruses. B. St. Louis encephalitis virus. C. La Crosse virus. D. Lassa fever virus.

ANS: D Arboviruses (arthropod-borne viruses) are RNA viruses that demonstrate strong tropism for the CNS. These viruses are transmitted to humans by mosquitoes, ticks, or sandflies. Important arboviruses in the western hemisphere include members of the alphaviruses (eastern equine encephalitis, western equine encephalitis, and Venezuelan equine encephalitis viruses), flaviviruses (St. Louis encephalitis virus), bunyaviruses (La Crosse virus), and Coltivirus (Colorado tick fever).

Question 3 Which immunosuppressive agent can increase a patient's risk of bacteremia? A. Cancer chemotherapy B. Corticosteroid therapy C. Transplant maintenance therapy D. All of the above

ANS: D Bacteremias are more frequent among persons with neoplasia (abnormal growth of new cells that may be benign or malignant), especially those with hematologic malignancies, those receiving immunosuppressive medication or chemotherapy, and those undergoing bone marrow transplantation. Persons with other chronic underlying diseases (e.g., diabetes, cirrhosis) and those receiving immunosuppressive therapy (e.g., those receiving glucocorticoids for rheumatoid arthritis, stem cell or solid organ transplant patients) are also at increased risk for bacteremia.

32. What is a chronic pneumonia? a. A viral pneumonia that lasts for months b. A pneumonia that is caused by a slow-growing bacteria such as Bacillus anthracis and takes months to resolve c. A bacterial pneumonia that become resistant to antibiotic therapy d. A pneumonia that appears to resolve clinically, but where radiographic lung abnormalities persist for a long period

ANS: D Bacterial pneumonias usually resolve completely over a period of weeks. On occasion, however, resolution of pneumonia is delayed, with radiographic lung abnormalities persisting far beyond the improvement of clinical symptoms. REF: page 799 OBJ: Level 1 - Recall

19. Why do most physicians treat otitis media empirically instead of obtaining cultures before prescribing antibiotics? a. It is hard to hard to obtain cultures from children. b. Cultures do not always correlate with the true pathogen. c. Pathogens causing otitis media never become resistant to antibiotics. d. The predominant infection causing organisms are known.

ANS: D Because the predominant pathogens for acute otitis media are known, obtaining specimens for culture before initiating therapy is unnecessary in the average case. REF: page 782 OBJ: Level 1 - Recall

27. What is the most important cause of iatrogenic diarrhea in adults? a. Yersinia enterocolitica b. Cryptosporidium jejunum c. Vibrio vulnificus d. Clostridium difficile

ANS: D C. difficile is the most important cause of hospital-acquired diarrhea in adults. This infection demonstrates the importance of normal colonic bacterial florae in preventing disease. REF: page 844 OBJ: Level 1 - Recall

18. What may candiduria be a sign of? a. Bladder or renal parenchymal infection b. Urinary tract fungus ball c. Disseminated candidiasis d. All of the above

ANS: D Candiduria may be an indication of bladder or renal parenchymal infection, a urinary tract fungus ball, or disseminated candidiasis. Predisposing factors include diabetes mellitus, antibiotic and corticosteroid therapy, female gender, instrumentations, and disturbance of urine flow. REF: page 892 OBJ: Level 1 - Recall

7. What condition presents as a localized area of mildly painful erythema, warmth, and swelling of the skin with poorly demarcated margins? a. Impetigo b. Carbuncles c. Furuncles d. Cellulitis

ANS: D Cellulitis is a diffuse inflammation and infection of the superficial skin layers. It appears as a localized area of mildly painful erythema, warmth, and welling of the skin with poorly demarcated margins. REF: page 813 OBJ: Level 2 - Interpretation

26. Efflux pumps a. allow nutrients into the cells through specialized channels in the bacteria's outer membrane. b. allow electrolytes into the cells through specialized channels in the bacteria's outer membrane. c. act as a semi-permeable membrane and maintain the cell's osmotic pressure. d. function as transporter proteins involved in the removal of toxic substances from the interior of the cell to the external environment.

ANS: D Efflux pumps are found in gram-positive and gram-negative bacteria and function as transporter proteins involved in the removal of toxic substances from the interior of the cell to the external environment. OBJ: Level 1: Recall

10. Elements of the respiratory tract that can help prevent infection include all the following EXCEPT: a. Nasal hair b. Normal florae c. Coughing d. Epiglottis

ANS: D Elements of the respiratory tract that help prevent infection include nasal hair, mucociliary cells that line mucosal surfaces, coughing, normal florae, and phagocytic inflammatory cells. REF: pages 775-776 OBJ: Level 2 - Interpretation

3. A group of swim team members break out in a rash (folliculitis) the day after swimming at the pool. What organism is probably responsible for this outbreak? a. Staphylococcus aureus b. Enterococcus c. Escherichia coli d. Pseudomonas aeruginosa

ANS: D Folliculitis is an inflammation and infection of hair follicles. S. aureus is the most common etiologic agent of folliculitis, although P. aeruginosa has been implicated in cases acquired from contaminated swimming pools or whirlpools. REF: page 814 OBJ: Level 2 - Interpretation

20. How is genital herpes spread? a. Hot tubs infected with herpes b. Towels used by people with herpes c. Contaminated toilet seats d. Sexual contact with secretions from infected sites

ANS: D Genital herpes is transmitted by sexual contact with secretions from infected sites. The virus is spread only rarely, if at all, by touching infected objects such as a toilet seat, towel, or hot tub. REF: page 918 OBJ: Level 1 - Recall

22. Gram stains of specimens for anaerobic cultures should be examined for all the following reasons, except a. the Gram stain reveals various types and relative number of bacteria present. b. certain morphotypes can provide a presumptive identification and will guide media selection. c. the Gram stain often reveals the presence of leukocytes. d. the Clinical and Laboratory Standards Institute (CLSI) guidelines recommend Gram stains on all anaerobic specimens.

ANS: D Gram-stained smears must be examined for several reasons. The Gram stain reveals the various types and relative number of organisms present. The presence of multiple distinct morphologic forms suggests that a polymicrobic infectious process is present. Certain morphotypes may provide a presumptive identification of organisms and serve as a guide to media selection. The Gram stain often reveals the presence of leukocytes. However, certain anaerobes produce necrotizing toxins (leukocidins) that destroy leukocytes. Finally, the Gram stain can serve as a quality control technique. OBJ: Level 1: Recall

7. What is the cause of reduced clearance of respiratory secretions that predisposes people to respiratory infections? a. Obstruction of a foreign body b. Alterations in the viscosity of the mucus c. Immature anatomic development d. All of the above

ANS: D In addition to age as a compromising factor, reduced clearance of secretions or obstruction of an area in either the upper or the lower respiratory tract predisposes to infection and can, on occasion, seriously compromise respiratory tract function. Decreased clearance of respiratory secretions may result from the following: immature anatomic development, transient reduction in function of the mucociliary mechanism, obstruction by a foreign body, previous disease that alters the normal respiratory tract anatomy, and alterations in the viscosity of mucus. REF: page 776 OBJ: Level 1 - Recall

Question 6 Lipopolysaccharide in gram-negative bacteria and the lipoteichoic acid and peptidoglycan in gram-positive bacteria cause which of the following to be released in the human body? A. Tumor necrosis factor (TNF) B. Interleukin (IL)-1 C. IL-6 D. All of the above

ANS: D In both cases, a bacterial membrane component (lipopolysaccharide, also known as endotoxin, in the case of gram-negative organisms; lipoteichoic acid and peptidoglycan in the case of gram-positive organisms) interacts with macrophages and causes release of TNF, interleukin-1 (IL-1), IL-6, and other proinflammatory cytokines, increasing endothelial activation, vascular permeability, blood flow, and recruitment of neutrophils.

14. Lipopolysaccharide in gram-negative bacteria and the lipoteichoic acid and peptidoglycan in gram-positive bacteria cause which of the following to be released in the human body? a. Tumor necrosis factor b. Interleukin (IL)-1 c. IL-6 d. All of the above

ANS: D In both cases, a bacterial membrane component (lipopolysaccharide, also known as endotoxin, in the case of gram-negative organisms; lipoteichoic acid and peptidoglycan in the case of gram-positive organisms) interacts with macrophages and causes release of tumor necrosis factor (TNF), interleukin-1 (IL-1), IL-6, and other proinflammatory cytokines, increasing endothelial activation, vascular permeability, blood flow, and recruitment of neutrophils. REF: page 874 OBJ: Level 2 - Interpretation

5. What is the most common clinical manifestation associated with continuous bacteremia? a. Meningitis b. Pleurisy c. Encephalitis d. Endocarditis

ANS: D Infective endocarditis is the most common clinical manifestation associated with continuous bacteremia, although other endovascular sources, such as infected intravascular catheters or septic thrombi, can result in continuous bacteremia. REF: page 871 OBJ: Level 1 -

Question 2 What is the most common clinical manifestation associated with continuous bacteremia? A. Meningitis B. Pleurisy C. Encephalitis D. Endocarditis

ANS: D Infective endocarditis is the most common clinical manifestation associated with continuous bacteremia, although other endovascular sources, such as infected intravascular catheters or septic thrombi, can result in continuous bacteremia.

13. This antibiotic affects the DNA replication by targeting topoisomerases II and IV, enzymes considered important in controlling DNA replication. a. Glycopeptide b. Sulfamethoxazole c. Trimethoprim d. Quinolone

ANS: D Quinolones disrupt the DNA replication cycle of bacteria by targeting topoisomerases II and IV. Interestingly, the targets of quinolones appear to be selective, targeting DNA gyrase in gram-negative bacteria and topoisomerase IV in gram-positive bacteria. However, newer quinolones appear to have high affinity for both targets. OBJ: Level 1: Recall

43. Insertion sequences are a. circular structures present in bacteria that contain genes encoding proteins and RNA, and the capacity to self-replicate and portion into daughter cells during cellular division. b. DNA elements that encode transposition and excision function, and can transpose from one place on the chromosome to another. c. genetic elements capable of integrating resistance genes (cassettes) by an integron-encoded, site-specific recombinase. d. DNA elements found in bacteria that carry genes only for the enzymes needed to promote their own transposition.

ANS: D Insertion sequences are transposons found in bacteria that carry genes only for the enzymes needed to promote their own transposition. Insertion sequence elements can form composite transposable genetic elements, with the insertion elements forming the proximal and distal ends, and the genetic material that codes for antibiotic resistance located in between. OBJ: Level 1: Recall

21. Intrinsic mechanisms of resistance are a. those that inhibit protein synthesis and RNA transcription. b. those that a bacterium acquires through plasmids. c. also called inducible enzymes. d. innate characteristics of the bacterium and transmitted to progeny.

ANS: D Intrinsic mechanisms of resistance are carried in the bacterial genome and transmitted from generation to generation. OBJ: Level 1: Recall

16. What organisms growing in a urine culture can be considered contaminants? a. Enterobacteriaceae b. Streptococcus spp. c. Fungus d. Bacillus spp.

ANS: D Isolation of Bacillus spp. can almost be considered contamination. Urinary tract infections (UTIs) truly caused by the organism are exceedingly rare. REF: page 892 OBJ: Level 1 - Recall

28. A vaginal swab is received for anaerobic culture. How should this request be handled or processed? a. Plate material to anaerobic plates and incubate b. Place swab in culture broth and incubate c. Place swab in sterile saline, vortex, use saline to inoculate anaerobic plates then incubate d. Contact the physician, this is an unacceptable specimen

ANS: D Material from vaginal mucosa is in general unacceptable for anaerobic cultures. Body sites with normal microbiota are seldom used for culturing anaerobes. OBJ: Level 2: Interpretation

17. The four major groups of anaerobic gram-negative bacilli include all the following, except a. Bacteroides fragilis. b. Porphyromonas. c. Prevotella. d. Mobiluncus.

ANS: D Most of the non-spore-forming, anaerobic, gram-negative bacilli involved in human infectious processes are found as members of the indigenous microbiota. Fortunately, only a few of the genera are commonly encountered in clinical specimens, which include the four major groups: the B. fragilis group, Porphyromonas spp., Prevotella spp., and Fusobacterium spp. OBJ: Level 1: Recall

13. What condition is an overgrowth of anaerobic bacteria and a decrease in lactobacillus in the vagina? a. Endometritis b. Syphilis c. Gonorrhea d. Bacterial vaginosis

ANS: D No single agent causes bacterial vaginosis. Instead, this condition results primarily from a disruption of the normal vaginal flora, with an overgrowth of anaerobic bacteria and a decrease in lactobacillary flora. REF: page 907 OBJ: Level 1 - Recall

14. All of the following are non-spore-forming, anaerobic, gram-positive bacilli, except a. Actinomyces. b. Bifidobacterium. c. Eubacterium. d. Clostridium.

ANS: D Non-spore-forming, anaerobic, gram-positive bacilli include Actinomyces, Bifidobacterium, Eubacterium, Mobiluncus, Lactobacillus, and Propionibacterium spp. Clostridia are spore formers. OBJ: Level 2: Interpretation

4. A patient's normal florae can be altered by all of the following EXCEPT: a. Broad-spectrum antibiotics b. Recent hospitalization c. Chronic illness d. Visited a nursing home

ANS: D Normal upper respiratory tract florae in an asymptomatic patient may change depending on the clinical setting. Patients who have previously received broad-spectrum antibiotics, have been hospitalized recently, or have chronic illnesses may have different pharyngeal florae. REF: page 775 OBJ: Level 1 - Recall

13. What is the cause of most uncomplicated urinary tract infections (UTIs)? a. Pseudomonas aeruginosa b. Staphylococcus epidermidis c. Streptococcus agalactiae d. Escherichia coli

ANS: D Of the Enterobacteriaceae, antibiotic-susceptible strains of E. coli that emanate from the patient's own fecal florae cause most uncomplicated UTIs. REF: page 891 OBJ: Level 1 - Recall

25. What types of stools are characteristic of cholera? a. Black-blood stools b. Coffee-ground stools c. Black tar stools d. Rice-water stools

ANS: D Once in the cell, through various enzymatic effects, the toxin results in an increase in the amount of cyclic adenosine monophosphate, which causes the cell to secrete large amounts of water and electrolytes. This increased secretion causes the rice-water stools characteristic of cholera. REF: page 844 OBJ: Level 2 - Interpretation

4. What substances do organisms that use oxygen have to protect themselves from superoxide anions? a. Hyaluronidase and proteases b. Exotoxins and superoxide dismutase c. Enterotoxins and lipase d. Superoxide dismutase and catalase

ANS: D Organisms that use oxygen have one or more enzymes to protect them from superoxide anions and their toxic derivatives. These enzymes include superoxide dismutase and catalase. OBJ: Level 1: Recall

10. What condition causes the nail margin to become painful, red, warm, and swollen with pus? a. Furuncle b. Carbuncle c. Erysipelas d. Paronychia

ANS: D Paronychia is an infection of the cuticle surrounding the nail bed. Cases generally follow minor trauma, such as removing a hangnail. The involved part of the finger at the nail margin becomes painful, red, warm, and swollen, and pus may be expressed from around the nail bed. REF: page 814 OBJ: Level 2 - Interpretation

8. The symptoms of pyelonephritis include all the following EXCEPT: a. Flank pain b. Costovertebral angle tenderness c. Fevers d. Septicemia

ANS: D Patients with upper urinary tract infections (UTIs), such as pyelonephritis, present with flank pain, nausea, vomiting, fevers, and costovertebral angle tenderness. These symptoms may occur in the presence or absence of symptoms of cystitis. REF: page 890 OBJ: Level 1 - Recall

23. What is a porin? a. An inner membrane pore that allows proteins out into the cytoplasm b. Outer membrane pores that allow the membrane to "breathe" c. Substrates for enzymes that enable protein synthesis d. Outer membrane channels that permit the inflow of nutrients and the outflow of wastes

ANS: D Porins are outer membrane channels that permit the influx of nutrients and the efflux of waste products. OBJ: Level 1: Recall

39. Resistance to aminoglycosides is mediated by a. efflux. b. changes in the target site. c. impermeability or by enzymatic modification of amino and hydroxy moieties appended to the cyclitol rings. d. All of the above

ANS: D Resistance to aminoglycosides is mediated by efflux, changes in target site, impermeability, or enzymatic modification of the amino and hydroxy moieties appended to the cyclitol rings. The most clinically relevant is enzymatic modification, which prevents recognition of the 16S binding sites and subsequent inhibition of mRNA translation. OBJ: Level 1: Recall

15. What common condition will predispose individuals to acute sinusitis? a. Cold sores b. Ear infections c. Nosebleeds d. Allergies

ANS: D Respiratory allergies also predispose individuals to acute sinusitis. REF: page 780 OBJ: Level 1 - Recall

30. All of the following features should be considered in a urinary tract infection (UTI) workup EXCEPT: a. Colony count of a pure or predominant organism b. Measurement of pyuria c. Presence or absence of symptoms d. Nitrite positive

ANS: D Routine workup of isolates and susceptibility testing must be tailored according to the patient at risk and the specimen type submitted. A flow diagram should take into account three features considered in all UTIs: colony count of a pure or predominant organism, measurement of pyuria, and presence or absence of symptoms (dysuria and frequency). REF: page 898 OBJ: Level 1 - Recall`

25. What causes rubella? a. Calicivirus b. Herpesvirus c. Paramyxovirus d. Togaviridae

ANS: D Rubella (German measles) is an acute exanthematous viral infection of children and adults caused by an RNA agent of the Togaviridae family. REF: page 824 OBJ: Level 1 - Recall

What causes rubella? A. Calicivirus B. Herpesvirus C. Paramyxovirus D. Togaviridae

ANS: D Rubella is a viral infection primarily of unvaccinated children that resembles measles. It is characterized by fever, rash, and lymphadenopathy. The virus is in the family Togaviridae and (genus Rubivirus).

15. What causes scarlet fever? a. S. aureus b. Endotoxin c. Proteases d. Erythrogenic toxin

ANS: D Scarlet fever is a characteristic form of group A streptococcal disease that occurs when the infecting strain produces a scarlatiniform or erythrogenic toxin. REF: page 832 OBJ: Level 1 - Recall

Question 5 What organism is primary found in septicemia originated from an upper urinary tract infection? A. Staphylococcus aureus B. Staphylococcus saprophyticus C. Pseudomonas aeruginosa D. E. coli

ANS: D Sepsis and septic shock are potential consequences of bacteremia.

13. What are two potential consequences of bacteremia? a. Endocarditis and meningitis b. Meningitis and encephalitis c. Encephalitis and hepatitis d. Sepsis and septic shock

ANS: D Sepsis and septic shock are potential consequences of bacteremia. REF: page 874 OBJ: Level 1 -

25. What evidence indicates the presence of anaerobes in cultures? a. A foul odor upon opening an anaerobic jar or bag b. Growth on the anaerobic plates, but not on the sheep blood agar (SBA) plates incubated in the CO2 incubator c. Colonies on kanamycin-vancomycin laked-blood agar (KVLBA) that fluoresce brick-red under ultraviolet light d. All of the above

ANS: D Several clues can alert the microbiologist that anaerobes might be present on the primary plates. These include (1) a foul odor upon opening an anaerobic jar or bag, (2) colonies present on the anaerobically incubated SBA plates but not on the CO2-incubated blood or chocolate agar plates, (3) good growth, more than 1 mm in diameter, of gray colonies on the Bacteroides bile esculin (BBE) plate, and (4) colonies on either the KVLBA or anaerobic SBA plate that fluoresce brick-red under ultraviolet light or a double zone of hemolysis on SBA incubated anaerobically. OBJ: Level 1: Recall

8. All the following viruses can resist inactivation by gastric acid EXCEPT: a. Enteroviruses b. Adenoviruses c. Parvovirus d. Herpesvirus

ANS: D Some viruses, such as enteroviruses, adenoviruses, and parvovirus, can resist inactivation by gastric acid. After initial replication at the site of mucosal colonization, viremia develops, followed by invasion of the central nervous system (CNS). REF: page 859 OBJ: Level 1 - Recall

12. Which antibiotic inhibits folate synthesis, providing the essential precursor molecule, pyridine thymidylate, needed in DNA synthesis? a. Vancomycin b. Quinolones c. Aminoglycosides d. Sulfamethoxazole

ANS: D Sulfamethoxazole blocks the step leading to the formation of one of the enzymes needed for folate synthesis. Because folate synthesis forms the essential precursor molecule—pyridine thymidylate, needed in DNA biosynthesis—the bacteria cannot replicate its DNA and dies. OBJ: Level 1: Recall

34. All of the following are approaches to treating anaerobic infections, except a. surgical therapy. b. hyperbaric oxygen. c. antitoxins. d. enzyme inactivators.

ANS: D Surgical therapy is the most important type of treatment, and in less serious cases, it may be the only type of therapy required. The use of hyperbaric oxygen to force oxygen into necrotic tissue not only delivers oxygen to oxygen-starved tissues but aids in killing anaerobes that are present at the site. The primary role of antimicrobial agents is to limit the local and systemic spread of the organism. In cases of tetanus and botulism, antitoxins are used to neutralize the effect of neurotoxins produced by Clostridium tetani and C. botulinum, respectively. OBJ: Level 1: Recall

7. What is an advantage to using PACE 2 for detection of Neisseria gonorrhea? a. There is no advantage. b. You can also find syphilis. c. You can also find Cryptosporidium. d. You can also find Chlamydia.

ANS: D The PACE 2 is a DNA probe that hybridizes the gonococcal rRNA. This is a sensitive test that allows test batching, which is another advantage because Chlamydia trachomatis can be simultaneously detected from the same specimen. OBJ: Level 1 - Recall

17. How does the biofilm protect the organism? a. By inhibiting phagocytosis b. By inhibiting chemotaxis c. By suppressing the lymphoproliferative response d. All of the above

ANS: D The biofilm also protects the organism from host defenses by inhibiting phagocytosis, chemotaxis, and oxidative metabolism and by suppressing the lymphoproliferative response. It may also significantly increase the concentrations of antimicrobials required to inhibit the growth of coagulase negative staphylococci attached to the catheter. REF: page 874 OBJ: Level 1 -

17. The members of the polyketide class of antibiotics include all the following, except a. tetracycline. b. doxycycline. c. minocycline. d. oxycycline.

ANS: D The clinically useful tetracyclines are members of the polyketide class of antibiotics and are represented by tetracycline, doxycycline, and minocycline. OBJ: Level 1: Recall

6. All of the following organisms are found on the skin under normal conditions, except a. Propionibacterium. b. Peptostreptococcus. c. Streptococcus. d. Clostridium.

ANS: D The indigenous members of the skin biota include anaerobes. Propionibacterium acnes is frequently isolated from blood cultures, but its presence often represents contamination from the patient's skin resulting from poor site preparation during the venipuncture. Other anaerobes found on the skin include gram-positive cocci (e.g., Peptostreptococcus and Streptococcus). OBJ: Level 1: Recall

8. What type of diarrheal illness has no fever and no blood or pus in the stool? a. Diarrhea where the mucosal surface is invaded b. Diarrhea where the full bowel thickness is invaded c. Diarrhea caused by endotoxins d. Diarrhea caused by enterotoxins

ANS: D The lack of fever and absence of blood or pus in the stool points toward an enterotoxin-mediated illness. The bacteria associated with enterotoxin production do not invade the gut wall, and the toxin does not elicit an inflammatory response, so microscopic examination of the stool does not reveal any red or white blood cells. REF: page 840 OBJ: Level 2 - Interpretation

23. Where do most cerebral abscesses spread from? a. Middle ear infections b. Mastoiditis c. Paranasal sinus infections d. All of the above

ANS: D The majority of cerebral abscess occur because of spread from a contiguous focus of infection in the middle ear, mastoid cells, or paranasal sinuses. REF: page 864 OBJ: Level 1 - Recall

19. All of the following are common causes of viral encephalitis EXCEPT: a. Herpes viruses b. Enteroviruses c. Arboviruses d. Toroviruses

ANS: D The most common causes of encephalitis are viruses including herpes viruses, enteroviruses, and arboviruses. REF: page 859 OBJ: Level 1 - Recall

31. All of the following organisms have been implicated in a food-borne outbreak EXCEPT: a. Staphylococcus aureus b. Salmonella spp. c. Clostridium botulinum d. Vibrio cholerae

ANS: D The most commonly identified bacterial agents involved in food-borne outbreaks are Salmonella spp., Campylobacter jejuni, S. aureus, C. botulinum, and Clostridium perfringens. REF: page 839 OBJ: Level 1 - Recall

12. What is a common neurologic complication with the mumps? a. Encephalitis b. Meningoencephalitis c. Viremia d. Aseptic meningitis

ANS: D The mumps virus, a member of the family Paramyxoviridae, is an RNA virus that commonly causes parotitis. Aseptic meningitis is the most common neurologic complication. REF: page 860 OBJ: Level 1 - Recall

Question 4 What is a common neurologic complication with the mumps virus? A. Encephalitis B. Meningoencephalitis C. Viremia D. Aseptic meningitis

ANS: D The mumps virus, a member of the family Paramyxoviridae, is an RNA virus that commonly causes parotitis. Aseptic meningitis is the most common neurologic complication. Routine use of a vaccine has greatly diminished mumps virus infections.

16. What virus causes an acute self-limited diarrheal illness that is highly contagious in closed quarters but is associated with vomiting and low-grade fever? a. Astroviruses b. Rotaviruses c. Enteric arenaviruses d. Norovirus

ANS: D The noroviruses are named after the original strain (Norwalk virus), first isolated in patients from a town with that name in Ohio in 1968. These viruses cause an acute, self-limited diarrheal illness associated with vomiting and low-grade fever. The disease is highly contagious and is transmitted by the fecal-oral route, fecally contaminated food or water, environmental fomites, and by person-to-person contact. REF: page 842 OBJ: Level 2 - Interpretation

9. What predisposes a person to a polymicrobial bacteremia? a. Intravenous drug use b. Burns c. Gastrointestinal tract sources d. All of the above

ANS: D The predisposing factors in polymicrobial bacteremia include intravenous drug use, burns, and gastrointestinal tract sources. Especially at risk are immunocompromised patients, particularly those with alcoholism, granulocytopenia, extensive burns, diabetes mellitus, and chronic renal failure, and patients with vascular insufficiency as a result of ischemia. REF: page 873 OBJ: Level 1 -

9. What type of diarrheal illness has a rapid onset of symptoms after food ingestion (usually less than 12 hours)? a. Diarrhea where the mucosal surface is invaded b. Diarrhea where the full bowel thickness is invaded c. Diarrhea caused by endotoxins d. Diarrhea caused by enterotoxins

ANS: D The rapid onset of symptoms after food ingestion suggests that the illness in this case is enterotoxin mediated. The preformed toxin is usually present in the contaminated food and is then ingested by the patient, leading to the symptoms. Because toxin may already be present and can act fairly proximally in the bowel, the incubation period is relatively short, usually less than 12 hours. REF: page 840 OBJ: Level 2 - Interpretation

4. How does the small intestine try to prevent infection? a. Caustic secretions b. Acidic secretions c. Anatomic structure d. Peristalsis

ANS: D The small intestine has a different mechanism to prevent infection—it is constantly in motion (peristalsis). Organisms that rely on adhering to the intestinal wall to cause infection may be hampered by the peristaltic movements. REF: page 837 OBJ: Level 2 - Interpretation

29. What is thrush? a. Tinea unguium b. Tinea corporis c. Dermatophytosis d. Oral candidiasis

ANS: D The term thrush is applied to a specific form of oral candidiasis characterized by white, curdlike patches on the tongue or elsewhere on the mucosal surface of the oropharynx. REF: page 811 OBJ: Level 1 - Recall

22. What is the most commonly used method to collect urine samples? a. Catheterized specimen b. Suprapubic aspirate c. First morning specimen d. Voided midstream specimen

ANS: D The voided midstream collection, in which the patient collects the urine specimen, is the most commonly used method in clinical practice. REF: page 894 OBJ: Level 1 - Recall

8. What is the advantage of performing NAAT for cases of gonococcal urethritis? a. There is no advantage. b. You can also find syphilis. c. You can also find Cryptosporidium. d. You can also find Chlamydia.

ANS: D There are several Food and Drug Administration (FDA)-approved NAAT assays available with very high rates of sensitivity and specificity (more than 95%) and allow combination testing for N. gonorrhoeae and C. trachomatis (Table 38-3). REF: page 907 OBJ: Level 1 - Recall

21. What can happen when a transient bacteremia is produced from a dental procedure or a superficial skin infection? a. Hepatitis can result. b. Pneumonia can result. c. Deep vein thrombosis can result. d. Cardiac valves can be seeded with bacteria.

ANS: D Transient bacteremia (from dental procedures or a superficial skin infection) can seed cardiac valves with bacteria. These organisms multiply within a dense vegetation composed of bacteria and fibrin, protected from killing by neutrophils, and give rise to a continuous bacteremia, which can then seed other organs. REF: page 875 OBJ: Level 2 - Interpretation

4. What condition results when a procedural manipulation of a particular body site that is colonized by normal florae occurs? a. Continuous bacteremia b. Intermittent bacteremia c. Septic shock d. Transient bacteremia

ANS: D Transient bacteremia usually occurs after a procedural manipulation of a particular body site that is colonized by indigenous florae. Such sites include the mouth and the gastrointestinal and urogenital tracts REF: page 871 OBJ: Level 1 -

4. Urinary tract infection (UTI) in children is associated with significant morbidity and long-term medical problems, including all the following EXCEPT: a. Impaired renal function b. Hypertension c. End-stage renal disease d. Hemolytic-uremic syndrome

ANS: D UTI in children is associated with great morbidity and long-term medical problems, including impaired renal function, hypertension, end-stage renal disease, and complications of pregnancy as an adult. REF: page 888 OBJ: Level 1 - Recall

26. Because urine is an excellent supportive medium for bacteria growth, how must urine specimens be handled after collection? a. Store at room temperature for up to 24 hours. b. Process the refrigerated specimen within 24 hours. c. Store in the refrigerator for 48 hours. d. Immediately refrigerate.

ANS: D Urine is an excellent supportive medium for growth of most uropathogens and therefore must be immediately refrigerated or preserved. Generally, urine should be refrigerated, received, and processed in the laboratory within 2 hours. REF: page 895 OBJ: Level 1 - Recall

21. What is a circumscribed, hyperkeratotic, rough-textured, painless papule called? a. Skin tick b. Mole c. Freckle d. Wart

ANS: D Warts can manifest in a variety of skin and mucous membrane lesions. These include common warts (circumscribed, hyperkeratotic, rough-textured, painless papules varying in size from a pinhead to large masses), filiform warts (delicate elongated and pointed lesions that may reach 1 cm in length), laryngeal papillomas (located on the vocal cords and epiglottis of children), flat warts (smooth, slightly elevated, usually multiple lesions varying in size from 1 mm to 1 cm), venereal warts or condyloma acuminata (cauliflower-like fleshy growths seen most often in the genital and perianal regions—to be differentiated from condyloma lata of secondary syphilis), flat papillomas of the cervix; and plantar warts (flat, hyperkeratotic lesions of the plantar surface of the feet, which are frequently painful). REF: page 827 OBJ: Level 2 - Interpretation

26. How are suspected colonies of anaerobes processed? a. Gram stain morphology and reaction is observed. b. An aerotolerance test is set up. c. A pure culture/subculture plate is inoculated and appropriate disks are added. d. All of the above.

ANS: D When anaerobes are suspected, the aforementioned steps must be performed and recorded for each colony morphotype present on the anaerobic blood agar plate to initiate presumptive identification of the isolates. OBJ: Level 1: Recall

24. What is the major cause for chronic bronchitis? a. Acute bronchitis b. Respiratory allergies c. Pneumonia d. Smoking

ANS: D Whereas acute bronchitis is usually of infectious etiology, chronic bronchitis is usually caused by long-term cigarette smoking and occasionally by other toxic exposures. REF: page 786 OBJ: Level 1 - Recall

4. All of the following conditions can occur in women with undiagnosed gonorrhea EXCEPT: a. Salpingitis b. Endometritis c. Pelvic inflammatory disease (PID) d. Pharyngitis

ANS: D Women with undiagnosed gonorrhea are in danger of developing salpingitis, endometritis, and PID. REF: page 907 OBJ: Level 1 - Recall

11. The patient's immune system attempts to control infection via which of the following mechanisms? a. Antibodies b. Complement activation c. Phagocytosis d. Filtering mechanisms in the lymphatics e. All of the above

ANS: E Once bacteremia occurs, the patient's immune system attempts to control infection via antibodies, which opsonize organisms and allow complement-mediated killing, as well as by phagocytosis. In addition, filtering mechanisms in the lymphatics and large vascular beds in the liver and spleen may sequester organisms and allow their destruction. REF: page 873 OBJ: Level 1 -

Which gram-negative bacilli produce brown to black pigment on KVA agar and brick red fluorescence when exposed to an ultraviolet (UV) light source? A. Porphyromonas spp. and Prevotella spp. B. Fusobacterium spp. and Actinomyces spp. C. Bacteroides spp. and Fusobacterium spp. D. All of these options

ANS:A

Question 23 Select the primary and differential media of choice for recovery of most fecal pathogens. A. MacConkey, blood, birdseed, and Campylobacter (Campy) agars B. Hektoen, MacConkey, MacConkey-Sorbitol, Campy blood, colistin-nalidixic acid (CNA) agars; Selenite-F broth (SEL) C. CNA and Christensen urea agars and thioglycollate media D. Blood, Campy, Mueller-Hinton agars, and thioglycollate media

B

Which Clostridium spp. causes pseudomembranouscolitis or antibiotic-associated colitis? A. C. ramosum B. C. difficile C. C. perfringens D. C. sporogenes

B C. difficile is also implicated in hospital acquireddiarrhea and colitis. Clinical testing for C. difficileincludes culture and cytotoxin testing. Becauseculture takes 3 days and will detect nontoxigenicstrains that do not cause diarrheal disease,immunoassays using antibodies against either theA toxin or both the A and B toxins are most frequentlyemployed. Assays detecting both toxins are onlyslightly more sensitive, since infections producingonly B toxin are infrequent. The cytotoxin assayrequires that specimens be shipped to a referencelaboratory on dry ice or kept at 4°C-6°C if donein-house.

The following characteristics of an obligate anaerobic gram-negative bacilli best describe which of the listed genera? Gram stain: long, slender rods with pointed ends Colonial appearance: dry bread crumbs or"fried-egg" appearance Penicillin 2-unit disk test: Susceptible A. Bacteroides spp. B. Fusobacterium spp. C. Prevotella spp. D. Porphyromonas spp

B Fusobacterium spp. are usually spindle-shaped,slim rods, whereas the other genera are smallrods (variable length for Bacteroides spp. and tinycoccoid rods for Prevotella and Porphyromonas spp.).Fusobacterium spp. and Porphyromonas spp. aresusceptible to penicillin 2-unit disks, while mostBacteroides spp. and Prevotella spp. are resistant

Question 9 What is the most common cause of travelers' diarrhea? A. Giardia lamblia B. Escherichia coli C. Entamoeba histolytica D. Clostridium difficile

B Travelers' diarrhea is most commonly caused by enteropathogenic E. coli. This illness has a short incubation period (usually <24 hours) and normally lasts between 1 and 3 days. If a diarrheal illness lasts longer than this or develops in the days or weeks after a traveler returns home, the patient more likely has a different pathogen.!

5. Methods other than packaged microsystems used to identify anaerobes include: A. Antimicrobial susceptibility testing B. Gas-liquid chromatography (GLC) C. Special staining D. Enzyme immunoassay

B Anaerobic bacteria can be identified by analysisof metabolic products using gas-liquidchromatography. Results are evaluated alongwith Gram staining characteristics, spore formation,and cellular morphology in order to make theidentification.

The classic form of food borne botulism is characterized by the ingestion of: A. Spores in food B. Preformed toxin in food C. Toxin H D. All of these options

B Foodborne botulism in adults and children is causedby ingestion of the preformed toxin (botulinumtoxins A, B, E, and F) in food. The neurotoxins ofC. botulinum are protoplastic proteins made duringthe growing phase and released during lysis of theorganisms. Confirmation of botulism is made bydemonstration of the toxin in serum, gastric, or stoolspecimens.

Gram-positive bacilli recovered from two blood cultures from a 60-year-old diabetic patient gave the following results: Spores seen = Neg Hemolysis = + (double zone) Motility = Neg Lecithinase = + Volatile acids by GLC (PYG) = acetic acid (A) and butyricacid (B) What is the most likely identification? A. Clostridium tetani B. Clostridium perfringens C. Clostridium novyi (B) D. Clostridium sporogenes

B Spores are generally not demonstrated from clinicalspecimens containing C. perfringens, which is the onlyspecies producing a double zone of hemolysis. Thereactions in the chart above distinguish the fourspecies listed.

Obligate anaerobic gram-negative bacilli that do not form spores grow well in 20% bile and are resistant to penicillin 2-unit disks are most likely: A. Porphyromonas spp. B. Bacteroides spp. C. Fusobacterium spp. D. Prevotella spp.

B The Bacteroides group grows well in 20% bile and isresistant to penicillin 2-unit disks with the exceptionof B. ureolyticus. Most Prevotella are also resistant topenicillin 2-unit disks, but most Fusobacterium andPorphyromonas are sensitive.

2. Which of the following most affects the oxidation-reduction potential (Eh or redox potential) of media for anaerobic bacteria? A. O2 B. Nitrogen C. pH D. Glucose

C The Eh is most affected by pH and is expressed atpH 7.0. In cultivating anaerobic bacteria, reducingagents such as thioglycollate and L-cysteine areadded to anaerobic transport and culture media inorder to maintain a low Eh. Certain anaerobes do notgrow in the media above a specific critical Eh level.

Antimicrobial susceptibility testing of anaerobes is done by which of the following methods? A. Broth disk elution B. Disk agar diffusion C. Microtube broth dilution D. β-Lactamase testing

C The anaerobes are not suited for the broth diskelution or disk agar diffusion tests because of theirslow rate of growth. Kirby-Bauer method referencecharts are not designed to be used as a reference ofsusceptibility for anaerobes.

Question 25 SITUATION: A group of elementary students became ill after eating undercooked ground beef prepared in the school cafeteria. The suspected pathogen, E. coli serotype 0157:H7, is usually recovered using which of the following media? A. Xylose lysine deoxycholate agar B. MacConkey agar C. MacConkey agar with sorbitol D. Hektoen agar

C

Question 20 A physician has requested a stool culture for Yersinia, which of the following would be the most appropriate medium to use? A. Thiosulfate-citrate-bile salt-sucrose B. Hektoen-enteric C. Colistin-irgasan-novobiocin D. Xylose-lysine-deoxycholate

C A selective differential medium for the isolation of Yersinia in stool samples is colistin-irgasan-novobiocin. These antimicrobial agents inhibit the growth of several species of bacteria, except Y. enterocolitica. Mannitol fermentation is indicated by the presence of colonies with red centers. This is characteristic of Y. enterocolitica. Aeromonas hydrophila produces similar colonies on this medium.

Question 7 The urea breath test is a noninvasive test to detect infection caused by A. Listeria monocytogenes. B. Vibrio cholerae. C. Helicobacter pylori. D. Campylobacter jejuni.

C H. pylori is associated with gastric ulcers. The strong urease activity of this organism will produce radioactive CO2 when a patient drinks a solution of radioactive urea. The labeled CO2 is absorbed into the blood stream and exhaled in the patient's breath in about 30 minutes.

Question 14 What virus is the leading cause of diarrhea in children younger than age 5 years? A. Enteric adenoviruses B. Astroviruses C. Rotavirus D. Calicivirus

C Rotaviruses are the major cause of diarrhea in children younger than age 5 years, causing an estimated 130 million episodes of illness worldwide each year.

Question 17 What toxin does Shigella spp. produce? A. Typhi B. Enterotoxin C. Shiga D. Campy

C The bacteria produce several toxins, one of which is the Shiga toxin, which can have cytotoxic, enterotoxic, and neurotoxic effects.

Question 10 What is the most common cause of death among patients with diarrhea? A. Sepsis B. Septic shock C. Dehydration D. Secondary bacterial infections

C The first step in the physical examination of a patient with a diarrheal illness is to determine the patient's state of hydration, as dehydration is the most common cause of death in patients with diarrhea.

Question 13 What common organism invades the full thickness of the bowel with lymphatic spread? A. Vibrio cholerae B. Campylobacter jejuni C. Salmonella Typhi D. Aeromonas spp.

C The most common invasive enteric organisms are S. Typhi and Yersinia enterocolitica.

Question 15 A fecal isolate identified as E. coli produces clear colonies on MacConkey agar with sorbitol. You should suspect A. Shigella sp. B. Enterotoxigenic E. coli. C. Enterohemorrhagic E. coli. D. The identification is incorrect.

C Unlike most other strains of E coli, enterohemorrhagic E. coli typically does not ferment sorbitol. These strains will therefore produce clear colonies on MacConkey agar with sorbitol.

Question 24 Cycloserine-cefoxitin-fructose agar (CCFA) is used for the recovery of: A. Yersinia enterocolitica B. Yersinia intermedia C. Clostridium perfringens D. Clostridium difficile

D

Question 22 This is a form of food poisoning that can be life threatening even for otherwise healthy patients. A. S. aureus B. B. cereus C. C. difficile D. C. botulinum

D Clostridium botulinum produces one of the most toxic substances known to humankind: botulism toxin. This substance is responsible for the food poisoning and it can be life threatening even for healthy individuals. S. aureus and B. cereus produce food poisoning, but that is usually self-limiting. C. difficile is an intestinal normal flora that can produce diarrhea through an opportunistic mechanism. These can be life threatening in compromised patients.

Question 18 What types of stools are characteristic of someone who has cholera? A. Black-blood stools B. Coffee-ground stools C. Black tar stools D. Rice-water stools

D Once in the cell, through enzymatic effects, the toxin results in an increase in the amount of cyclic adenosine monophosphate, which causes the cell to secrete large amounts of water and electrolytes. This increased secretion causes the rice-water stools characteristic of cholera. This disease occurs in parts of the world where rice is a major portion of the diet.

Identification of Clostridium tetani is based upon: A. Gram stain of the wound site B. Anaerobic culture of the wound site C. Blood culture results D. Clinical findings

D The culture and Gram stain of the puncture woundsite usually does not produce any evidence ofC. tetani. The diagnosis is usually based upon clinicalfindings, which are characterized by spastic musclecontractions, lockjaw, and backward arching of theback caused by muscle contraction.

Question 16 What is the environmental reservoir of Campylobacter? A. Lakes and rivers B. Fish C. Arthropod vector D. Wild and domestic animals

D The environmental reservoir of Campylobacter includes wild and domestic animals, most frequently birds. This is usually a foodborne infection, often with poultry as the source.

Question 11 What type of diarrheal illness has no fever and no blood or pus in the stool? A. Diarrhea where the mucosal surface is invaded B. Diarrhea where the full bowel thickness is invaded C. Diarrhea caused by endotoxins D. Diarrhea caused by enterotoxins

D The lack of fever and absence of blood or pus in the stool points toward an enterotoxin-mediated illness. The bacteria associated with enterotoxin production do not invade the gut wall, and the toxin does not elicit an inflammatory response, so microscopic examination of the stool does not reveal any red or white blood cells. The enterotoxin can be produced outside the body and consumed in contaminated food.

Question 8 Presence of red colonies with black centers on xylose-lysine-decarboxylase medium is indicative of: A. lactose fermentation and utilization of citrate. B. lactose fermentation and H2S positive. C. nonlactose fermentation and tryptophan positive. D. nonlactose fermenter and H2S positive.

D Xylose-lysine-decarboxylase medium is a selective and differential medium most appropriate for stool cultures. The red colonies indicate the inability to use lactose or sucrose, two carbohydrates present in the medium. The black center indicates H2S production. This pattern is suggestive of Salmonella.

Which Bacteroides spp. is noted for "pitting" ofthe agar and is sensitive to penicillin 2-unit disks? A. B. vulgatus B. B. ovatus C. B. thetaiotaomicron D. B. ureolyticus

D B. ureolyticus is the only species listed that is susceptibleto penicillin and produces urease. The other organismslisted are resistant to penicillin.

9. Which of the following organisms will display lipase activity on egg yolk agar? A. Clostridium botulinum B. Clostridium sporogenes C. Clostridium novyi (A) D. All of these options

D Lipase is produced by some Clostridium spp. and isseen as an iridescent pearly layer on the surface of thecolonies that extends onto the surface of the egg yolkagar medium surrounding them. C. perfringens, themost frequently isolated Clostridium species, isnegative for lipase production.

1. Obligate anaerobes, facultative anaerobes, and microaerophiles are terms referring to bacteria that require: A. Increased nitrogen B. Decreased CO2 C. Increased O2 D. Decreased O

D The anaerobic bacteria are subdivided according totheir requirement for O 2. Obligate anaerobes arekilled by exposure to atmospheric O 2 for 10 min orlonger. Facultative anaerobes grow under aerobic oranaerobic conditions. Microaerophilic organisms donot grow in an aerobic incubator on solid media andonly minimally under anaerobic conditions. However,they will grow in minimal oxygen (5% O 2). Superoxidedismutase (SOD) is produced by many anaerobes,which catalyzes the conversion of superoxide radicalsto less toxic H2 O2 and molecular O2

Anaerobic bacteria are routinely isolated from all of the following types of infections except: A. Lung abscesses B. Brain abscesses C. Dental infections D. Urinary tract infections

D The incidence of anaerobic bacteria recoveredfrom the urine is approximately 1% of isolates. Theother three types of infection are associated with a60%-93% incidence of anaerobic recovery. Urine isnot cultured routinely under anaerobic conditionsunless obtained surgically (e.g., suprapubicaspiration)

All of the following genera are anaerobic cocci that stain gram positive except: A. Peptococcus spp. B. Peptostreptococcus spp. C. Streptococcus spp. D. Veillonella spp.

D Veillonella spp. are gram-negative cocci. All fourgenera are part of the normal human flora and arethe anaerobic cocci most frequently isolated fromblood cultures, abscesses, wounds, and body fluids.The Streptococcus spp. are facultative anaerobes, butonly Strterm-56eptococcus intermedius is classified as anobligate anaerobe.

Which Clostridium species is most often recovered from a wound infection with gas gangrene? A. C. sporogenes B. Clostridium sordellii C. C. novyi D. C. perfringens

D Wounds infected with clostridia are characterized byinvasion and liquefactive necrosis of muscle tissuewith gas formation. The most frequent isolate isC. perfringens followed by C. novyi and C. septicum

What do these have in common: Alphaviruses St. Louis encephaitis virus La Crosse virus

Important arboviruses

Classifications of bacteremias

Microbiology Acquisition Duration

What do these have in common: Syphilitic meningitis Gummatous neursyphilis Parenchymatous neurosyphilis

Syphilitic involvement in the central nervous system

Functions performed by SPS:

a. Anticoagulation b. Prevention of phagocytosis d. Inactivate certain antibiotics

What condition presents as a localized area of mildly painful erythema, warmth, and swelling of the skin with poorly demarcated margins? a. Cellulitis b. Carbuncles c. Furuncles d. Impetigo

a. Cellulitis

What is the most common bacterium found on the skin? a. Coagulase-negative staphylococci b. Escherichia coli c. Coagulase-negative streptococci d. Pseudomonas aeruginosa

a. Coagulase-negative staphylococci

Colonizers of indwelling catheters

a. Coagulase-negative staphylococci c. Staphylococcus aureus d. Enterococcus spp.

Altered clinical laboratory values that may be indicative of bacteremia include:

a. Disseminated intravascular coagulation (DIC) b. Thrombocytopenia c. Coagulopathy

Orgs that are common in pneumonia and produce concurrent bacteremia

a. Enterobacter aerogenes c. Pseudomonas aeruginosa d. Staphylococcus aureus

What causes scarlet fever? a. Erythrogenic toxin b. Proteases c. S. aureus d. Endotoxin

a. Erythrogenic toxin

Bacteremia frequent fliers

a. Hematologic malignancies c. Those receiving immunosuppressive chemotherapy d. Those undergoing bone marrow transplantation

A common cause of eumycetoma: a. Madurella sp. b. Actinomyces sp. c. Fonsecaea sp. d. Candida albicans

a. Madurella sp.

What condition causes the nail margin to become painful, red, warm, and swollen with pus? a. Paronychia b. Carbuncle c. Erysipelas d. Furuncle

a. Paronychia

Which of the following organisms is responsible for impetigo? a. Streptococcus pyogenes b. Enterococcus faecalis c. Staphylococcus epidermidis d. Streptococcus agalactiae

a. Streptococcus pyogenes

In August, a 30-year-old man presents with an ulcer on his leg with swelling of the lymph nodes in the surrounding area. He reports taking numerous hikes in the woods behind is house hunting rabbits. He does not recall any animal bites. What disease should be considered in the differential diagnosis? a. Tularemia b. Brucellosis c. Rat bit fever d. Lyme disease

a. Tularemia

What organism is known to cause severe necrotic cellulitis and primary sepsis? a. Vibrio vulnificus b. V. parahaemolyticus c. Campylobacter spp. d. Staphylococcus epidermidis

a. Vibrio vulnificus

What is erysipelas? a. A synonym for carbuncle b. A superficial form of cellulitis c. A synonym for furuncle d. Inflammation of hair follicle

b. A superficial form of cellulitis

Common sites of bacteremia

b. Infected intravascular catheters c. The lung d. The abdomen

Purpura fulminans, a skin manifestation of disseminated intravascular coagulation, is associated with which condition? a. Salmonella b. Meningococcemia c. Hepatitis d. Encephalitis

b. Meningococcemia

Factors associated with unfavorable outcomes of bacteremia

b. Polymicrobial bacteremia c. Presence of malignancy d. AIDS

A group of swim team members breaks out in a rash (folliculitis) the day after swimming at the pool. What organism is probably responsible for this outbreak? a. Enterococcus sp. b. Pseudomonas aeruginosa c. Escherichia coli d. Staphylococcus aureus

b. Pseudomonas aeruginosa

What organism produces "rat bite fever?" a. Staphylococcus aureus b. Streptobacillus moniliformis c. Borrelia burgdorferi d. Chlamydia trachomatis

b. Streptobacillus moniliformis

What do these have in common: Herpes viruses Enteroviruses Arboviruses

common causes of encephalitis

Common Factor: Streptococcus pneumoniae Haemophilus influenzae Neisseria Meningitidis

common causes of meningitis

What is ringworm? a. A parasitic skin infection b. A viral skin infection c. A fungal skin infection d. A bacterial skin infection

c. A fungal skin infection

What is swimmer's itch? a. Arthropods deposit larvae in human skin, causing dermatitis. b. Dermatitis is caused by Pseudomonas spp. c. Cercariae larvae penetrate human skin, causing dermatitis. d. Dermatitis is caused by Vibrio spp.

c. Cercariae larvae penetrate human skin, causing dermatitis.

All of the following viruses cause a characteristic viral syndrome, which includes severe bleeding manifestations, except: a. Marburg virus. b. Junin virus. c. Rabies virus. d. Ebola virus.

c. Rabies virus.

What is the most well-known type of myonecrosis? a. Necrotizing fasciitis b. Ebola hemorrhage c. Gas gangrene d. Tetanus

c. Gas gangrene

What is thrush? a. Dermatophytosis b. Tinea unguium c. Oral candidiasis d. Tinea corporis

c. Oral candidiasis

Besides antimicrobial therapy, how are most carbuncles treated? a. Moist heat, then cold compresses b. Teabags to draw the bacterial toxins out c. Surgical drainage d. Squeezing to express the pus and necrotic tissues

c. Surgical drainage

What is a circumscribed, hyperkeratotic, rough-textured, painless papule called? a. Skin tick b. Freckle c. Wart d. Mole

c. Wart

What happens in the later stages of toxic shock syndrome as a result of the production of toxic shock syndrome toxin-1? a. Disseminated intravascular coagulation b. Bacteremia c. Bruising d. Desquamation

d. Desquamation

The clinical syndrome of Rocky Mountain spotted fever can be confused with which of the following conditions? a. Smallpox b. Allergic reactions c. Lyme disease d. Meningococcemia

d. Meningococcemia

What organism causes the Buruli ulcer? a. Mycobacterium leprae b. Corynebacterium jejuni c. Streptococcus agalactiae d. Mycobacterium ulcerans

d. Mycobacterium ulcerans

What causes erythema infectiosum? a. Herpesvirus b. Paramyxovirus c. Togaviridae d. Parvovirus

d. Parvovirus

What is herpetic whitlow? a. Primary herpetic lesions of the anus b. Primary herpetic lesions of the genitals c. Primary herpetic lesions of the lip d. Primary herpetic lesions of the finger

d. Primary herpetic lesions of the finger

What disease results from a reactivation of the varicella-zoster virus that presents as vesicular eruption in a unilateral dermatomal distribution? a. Infectious mononucleosis b. Rubella c. Chicken pox d. Shingles

d. Shingles

What is the best method of diagnosing scabies? a. Enzyme immunoassay b. Polymerase chain reaction c. Culture d. Skin scrapings

d. Skin scrapings

What is a form of folliculitis in bearded men? a. Impetigo b. Furuncle c. Carbuncle d. Sycosis barbae

d. Sycosis barbae

What causes rubella? a. Herpesvirus b. Calicivirus c. Paramyxovirus d. Togaviridae

d. Togaviridae

What do these have in common: Enteroviruses Adenoviruses Parvovirus

resist inactivation by gastric acid