Microbiology Harr
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, Campy, colistin-nalidixic acid (CNA) agars C. CNA and Christensen urea agars and thioglycollate media D. Blood, Campy, Mueller-Hinton agars, and thioglycollate media
Correct Answer: B
Slime production is associated with which Staphylococcus species? A. S. aureus B. S. epidermidis C. S. intermedius D. S. saprophyticus
Correct Answer: B
Which technique is used for the confirmation of infection with human immunodeficiency virus (HIV-1)? A. Western blot (immunoblot) assay B. Enzyme-linked immunosorbent assay (ELISA) C. Complement fixation D. p24 Antigen testing
Correct Answer: A
The majority of Haemophilus influenzae infections are caused by which of the following capsular serotypes? A. a B. b C. c D. d
Correct Answer: B
The following organism are linked with specific, relevant information. The incorrect combination is: A. Strongyloides stercoralis-internal autoinfection B. Echinococcus granulosus-hydatid examination C. Toxoplasma-serology D. Balantidium coli-common within the United States
Correct Answer: D
The examination of sputum may be necessary to diagnose infection with: A. Paragonimus westermani B. Trichinella spiralis C. Wuchereria bancrofti D. Fasciola hepatica
Correct Answer: A
The g-ALA test (fro porphyrins_ is a confirmatory procedure for which test used for identification of Heamophilus species? A. X factor requirement B. V factor requirement C. Urease production D. Indole production
Correct Answer: A
The gram-positive non-spore-forming anaerobic rods most frequently recovered from blood cultures as a contaminant are: A. Propionibacterium acnes B. Clostridiumperfringens C. Staphylococcus intermedius D. Veillonella parvula
Correct Answer: A
The incorrect match between the organism and one method of acquiring the infection is: A. Trypanosoma brucei rhodesiense- bite of sand fleas B. Giardia lamblia- ingestion of water contaminated with cysts C. Hookworm-skin penetration of larvae form soil D. Toxoplasma gondii- ingestion of raw or rare meats
Correct Answer: A
The microsporidia are protozoans (now classified with the fungi)t that have been implicated in human disease primarily in: A. Immunocompromised patients B. Pediatric patients under the age of 5 years C. Adult patients with congenital immunodeficiencies. D. Patients who have been traveling in the tropics
Correct Answer: A
The most common causes of viral pneumonia in adults are: A. Influenza and adenovirus B. Hepatitis A and B viruses C. Coxsackie A and B viruses D. Herpes simplex and CMV
Correct Answer: A
The most prevalent helminth to infect humans is: A. Enterobius vermicularis, the pinworm B. Ascaris lumbricoides, the large intestinal roundworm C. Taenia saginata, the tapeworm D. Schistosoma mansoni, one of the blood flukes
Correct Answer: A
The most rapid definitive diagnosis of a genital herpes simplex (HSV-2) infection in a 20-year-old man is made by which method? A. Direct immunofluorescence test for viral antigen in vesicle fluid B. Titer of serum and seminal fluid for antibodies to herpes simplex C. Detection of antiherpes simplex in seminal fluid D. Cell culture of vesicle fluid
Correct Answer: A
The mycelial form of which dimorphic mold produced thick-walled, rectangular, or barrel-shaped alternate arthroconidia? A. Coccidiodes immitis B. Sporothrix schenckii C. Histoplasma capsulatum D. Blastomyces dermatitidis
Correct Answer: A
The urease test is needed to differentiate Mycobacterium scrofulaceum from which of the following mycobacteria? A. M. gordonae B. M. kansasii C. M. avium-intracellulare comple D. M. bovis
Correct Answer: A
The yeast form of which dimorphic mold shows a large parent yeast cell surrounded by smaller budding yeast cells? A. Paracoccidioides brasiliensis B. Sporothrix schenckii C. Coccidioides immitis D. Histoplasma capsulatum
Correct Answer: A
Three blood cultures taken from a 30-year-old cancer patient receiving chemotherapy and admitted with a urinary tract infection grew lactose-negative, motile, gram-negative rods prior to antibiotic therapy. Given the following biochemical reactions, which is the most likely organism? -H2S (TSI)=+ -VP=Neg -DNase=+ -Gelatin hydrolysis=+ -Ornithine decarboxylase=Neg -Indole=+ -Citrate=Neg -Phenylalanine deaminase=+ -MR=+ -Urease=+ A. Proteus vulgaris B. Proteus mirabilis C. Serratia marcescens D. Klebsiella pneumoniae
Correct Answer: A
Tinea versicolor is a skin infection caused by: A. Malassezia furfur B. Trichophyton rubrum C. Trichophyton schoenleinii D. Microsporum gypseum
Correct Answer: A
Two helminth eggs that may resemble one another are: A. Diphyllobothrium latum and Paragonimus westermani B. Opisthorchis sinensis and Fasciolopsis buski C. Taenia saginata and Hymenolepis nana D. Ascaris lumbricoides and Trichostrongylus
Correct Answer: A
Visceral larva migrans is associated with which of the following organisms? A. Toxocara-serology B. Onchocerca-skin snips C. Dracunculus-skin biopsy D. Angiostrongylus-CSF examination
Correct Answer: A
What is the purpose of adding 0.025%-0.050% sodium polyanetholsulfanate (SPS) to nutrient broth media for the collection of blood cultures? A. It inhibits phagocytosis and complement B. It promotes formation of a blood clot C. It enhances growth of anaerobes D. It functions as a preservative
Correct Answer: A
What is the specimen of choice for the initial diagnosis of Pneumocytstis jirovecii (carinii) in an immunocompromised patient, such as someone with AIDS? A. Induced sputum B. Open-thorax lung biopsy C. CSF D. Urine
Correct Answer: A
When humans have hydatid disease, the causative agent and host classification are: A. Echinococcus granulosus- accidental intermediate host B. Echinococcus granulosus- definitive host C. Taenia solium- accidental intermediate host D. Taenia solium- definitive host
Correct Answer: A
When testing for coagulase properties, staphylococci isolates from a 67-year-old male diabetic patient showed a positive tube test (free coagulase). The organism should be identified as: A. Staphylococcus aureus B. Staphylococcus haemolyticus C. Staphylococcus saprophyticus D. Micrococcus luteus
Correct Answer: A
Which M. avium complex (MAC) organism is the most frequently isolated mycobacterium from AIDS patients? A. M. avium B. M. intracellulare C. M. scrofulaceum D. M. bovis
Correct Answer: A
Which Staphylococcus species, in addition to S. aureus, also produces coagulase? A. S. intermedius B. S. saprophyticus C. S. hominis D. All of these options
Correct Answer: A
Which atmospheric condition is needed to recover Campylobacter sp.. from specimens inoculated onto a Campy-selective agar at 35C-37C and 42C? A. 5% O2, 10% CO2, and 85% N2 B. 20% O2, 10% CO2, and 70% N2 C. 20% O2, 20% CO2, and 60% N2 D. 20% O2, 5% CO2, and 75% N2
Correct Answer: A
Which biochemical test are needed to differentiate Burkholderia cepacia from S. maltophilia? A. Pigment on blood agar, oxidase, DNase B. Pigment on MacConkey agar, flagellar stain, motility C. Glucose, maltose, lysine decarboxylase D. TSI, motility, oxidase
Correct Answer: A
Which biochemical tests should be performed in order to identify colorless colonies growing on MacConkey agar (swarming colonies on blood agar) from a catheterized urine specimen? A. Indole, phenylalanine deaminase, and urease B. Glucose, oxidase, and lactose utilization C. Phenylalanine deaminase and bile solubility D. H2S and catalase
Correct Answer: A
Which broth is used for the cultivation of anaerobic bacteria in order to detect volatile fatty acids as an aid to identification? A. Prereduced peptone-yeast extract-glucose (PYG) B. THIO broth C. Gram-negative (GN) broth D. Selenite (SEL) broth
Correct Answer: A
Which dematiaceous mold forms flask-shaped phialides, each with a flask-shaped collarette? A. Phialophora spp. B. Exophiala spp. C. Wangiella spp. D. All of these options
Correct Answer: A
Which genera of Enterobacteriaceae are usually nonmotile at 36C? A. Shigella, Klebsiella, and Yersinia B. Escherichia, Edwardsiella, and Enterobacter C. Proteus, Providencia, and Salmonella D. Serratia, Morganella, and Hafnia
Correct Answer: A
Which genus (in which most species are oxidase and catalase positive) of small gram-negative coccobacilli is associated mainly with animals but may cause endocarditis, bacteremia, as well as wound and dental infections in humans? A. Actinobacillus B. Pseudomonas C. Campylobacter D. Vibrio
Correct Answer: A
Which gram-negative bacilli produce black pigment 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
Correct Answer: A
Which group of streptococci is associated with erythrogenic toxin production? A. Group A B. Group B C. Group C D. Group G
Correct Answer: A
Which group of test best identifies the Morganella and Proteus genera? A. Motility, urease, and phenylalanine deaminase B. Malonate, glucose fermentation, and deoxyribonuclease (DNase) C. Indole, oxidase, MR, and VP D. Indole, citrate, and urease
Correct Answer: A
Which is the best rapid test to differentiate Plesiomonas shigelloides form a Shigella species on selective enteric agar? A. Oxidase B. Indole C. TSI D. Urease
Correct Answer: A
Which isolates of the Enterobacteriaceae family most commonly produce extended-spectrum B-lactamase (ESBL)? A. E. coli and Klebsiella pneumoniae B. Yersinia enteroclitica and Yersinia pestis C. Morganella morganii and Proteus vulgaris D. Salmonella typhi and Shigella sonnei
Correct Answer: A
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
Correct Answer: A
Which medium is recommended for the recovery of Brucella spp. from blood and bone marrow specimen? A. Biphasic Castenada bottles with Brucella broth B. Blood culture bottles with Brucella broth C. Bordet-Gengou agar plates and THIO broth D. Blood culture bottles with THIO
Correct Answer: A
Which of the following is the best, rapid, noncultural test to perform when Gardnerella vaginalis is suspected in a patient with vaginosis? A. 10% KOH test B. 3% H2O2 test C. 30% H2O2 test D. All of these options
Correct Answer: A
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. Cycloserin-cefoxitin-fructose agar (CCFA) D. THIO broth
Correct Answer: A
Kingella kingae is usually associated with which type of infection? A. Middle ear B. Endocarditis C. Meningitis D. Urogenital
Correct Answer: B
Fecal immunoassays have become more commonly used to diagnose infections with: A. Endolimax nana and Blastocystis hominis B. Giardia lamblia and Cryptosporidium spp. C. Ascaris lumbricoides and Trichuris trichiura D. Strongyloides stercoralis and Trichomonas vaginalis
Correct Answer: B
Following a hike in the woods, a young male noted a tick on his ankle. He removed the tick, but 2 weeks later noticed a circular, bull's eye rash at the site of the bit. Which specimen(s) should be obtained to establish a diagnosis of Lyme borreliosis? A. Lymph node biopsy, skin scraping B. Blood, CSF, and skin biopsy C. Hair, fingernails D. Saliva, sputum
Correct Answer: B
Massive hemolysis, blackwater fever, and central nervous system involvement are most common with: A. Plasmodium vivax B. Plasmodium falciparum C. Plasmodium ovale D. Plasmodium malariae
Correct Answer: B
Material from a fungus-ball infection produced colonies with a green surface on Sabouraud agar in 5 days at 30C. Microscopic examination showed club-shaped vesicles with sporulation only from the top half of the vesicle. This hyaline mold is most probably which Aspergillus spp.? A. A. niger B. A. funigatus C. A. flavus D. A terreus
Correct Answer: B
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
Correct Answer: B
Nonpathogenic Moraxella spp. capable of growing on selective media for Neisseria can be differentiated from Neisseria spp. by which test? A. Catalase test B. 10-unit penicillin disk C. Oxidase test D. Superoxol test
Correct Answer: B
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.
Correct Answer: B
Organism that should be considered in a nursery school outbreak of diarrhea include: A. Endolimax nan, Giardia lamblia, and Entamoeba coli B. Giardia lamblia, Dientamoeba fragilis, and Crytosporidium spp. C. Crystosporidium spp., Trichomonas vaginalis, and Entamoeba coli D. Pentatrichomonas hominis, Dientamoeba fragilis, and Endolimax nana
Correct Answer: B
Prereduced and vitamin K1-supplemented blood agar plates are recommended isolation media for: A. Mycobacterium marinum and Mycobacterium avium intracellulare B. Bacteroides, Peptostreptococcus, and Clostridium spp. C. Proteus spp. D. Enterococcus spp.
Correct Answer: B
Primary atypical pneumonia is caused by: A. Streptococcus pneumoniae B. Mycoplasma pneumoniae C. Klebsiella pneumoniae D. Mycobacterium tuberculosis
Correct Answer: B
Routine laboratory testing for Treponema pallidum involves: A. Culturing B. Serological analysis C. Acid-fast staining D. Gram staining
Correct Answer: B
The urease test, niger seed agar test, and the germ tube test are all used for the presumptive identification of: A. Rhodotorula rubra B. Cryptococcus neoformans C. Trichosporon cutaneum D. Candida albicans
Correct Answer: B
The yeast form of which dimorphic fungus appears as oval or elongate cigar shapes? A. Coccidioides immitis B. Sporothrix schenckii C. Histoplasma capsulatum D. Blastomyces dermatitidis
Correct Answer: B
Trimethoprim-sulfamethoxazole (SXT) disks are used along with bacitracin disks to differentiate which streptococci? A. a-Hemolytic streptococci B. B-Hemolytic streptococci C. Streptococcus pneumoniae D. Enterococcus faecalis
Correct Answer: B
Which two tests best differentiate S. bovis (group D, nonenterococcus) from Streptococcus salivarius? A. Bile esculin and 6.5% salt broth B. Starch hydrolysis and acid production form mannitol C. Bacitracin and PYR D. Trimethoprim-sulfamethoxazole susceptibility and PYR
Correct Answer: B
Which virus belonging to the Reoviridae group causes gastroenteritis in infants and young children but an asymptomatic infection in adults? A. Coxsackie V virus B. Rotavirus C. Respiratory syncytial virus D. Rhabdovirus
Correct Answer: B
Which of the following organisms are used as controls for rapid growers and slow growers? A. Mycobacterium fortuitum and Mycobacterium tuberculosis B. Mycobacterium avium-intracellulare complex and Mycobacterium tuberculosis C. Mycobacterium chelonie and Mycobacterium fortuitum D. Mycobacterium kansaii and Mycobacterium tuberculosis
Correct Answer: A
Which of the following products is responsible for satellite growth of haemophilus spp. around colonies of Staphylococcus and Neisseria spp. on sheep blood agar? A. NAD B. Hermin C. Indole D. Oxidase
Correct Answer: A
Which of the following reagents is added to detect the production of indole? A. p-Dimethylaminobenzaldehyde B. Bromcresol purple C. Methyl red D. Cytochrome oxidase
Correct Answer: A
Which of the following test should be performed for initial differentiation of Listeria monocytogenes from group B streptococci? A. Gram stain, motility at room temperature, catalase B. Gram stain, Camp test, H2S/TSI C. Oxidase, CAMP test, glucose D. Oxidase, bacitracin
Correct Answer: A
Which of the following test should be used to differentiate Staphylococcus aureus form Staphylococcus intermedius? A. Acetoin B. Catalase C. Slide coagulase test D. Urease
Correct Answer: A
Which of the following viruses is implicated along with Epstein-Barr virus as a cause of infectious mononucleosis? A. Cytomegalovirus (CMV) B. Coxsackie A virus C. Coxsackie B virus D. Hepatitis B virus
Correct Answer: A
Which of the following yeast enzymes is detected using birdseed (niger seed) agar? A. Phenol oxidase B. Catalase C. Urease D. Nitrate reductase
Correct Answer: A
Which organism is sometimes mistaken for Salmonella and will agglutinate in Salmonella polyvalent antiserum? A. C. feundii strains B. Proteus mirabilis strains C. S. sonnei strains D. E. coli
Correct Answer: A
Which organism typically produces "fried-egg" colonies on agar within 1-5 days of culture from a genital specimen? A. Mycoplasma hominis B. Borrelia burgdorferi C. Leptospira interrogans D. Treponema pallidum
Correct Answer: A
Which procedure is appropriate for culture of genital specimens in order to recover Chlamydia spp.? A. Inoculate cycloheximide-treated McCoy cells B. Plate onto blood and chocolate agar C. Inoculate into thioglycollate (THIO) broth D. Plate onto modified Thayer-Martin agar within 24 hours
Correct Answer: A
Which reagent(s) is (are) used to develop the red color indicative of a positive reaction in the nitrate reduction test? A. Sulfanilic acid and a-naphthylamine B. Ehrilich's and Kovac's reagents C. o-Nitrophenyl-B-D-galactopyranoside D. Kovac's reagent
Correct Answer: A
Which test group best differentiates Acinetobacter baumanii from P. aeruginosa? A. Oxidase, motility, NO3 reduction B. MacConkey growth, 37C growth, catalase C. Blood agar growth, oxidase, catalase D. Oxidase, TSI, MacConkey growth
Correct Answer: 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
Correct Answer: A
Which test is the most reliable for the detection of Mycoplasma pneumonia in serum and for the confirmation of diagnosis? A. EIA testing and direct antigen testing B. Cold agglutinin testing using Group O RBCs C. Culture on SP4 glucose broth with arginine D. Complement fixation
Correct Answer: A
Which two mycobacteria commonly isolated rom subcutaneous skin have an optimal growth temperature of 30C? A. M. haemophilum and M. ulcerans B. M. kansasii and M. xenopi C. M. gordonae and M. avium D. M. simiae and M. avium
Correct Answer: A
Which virus has been implicated in adult gastroenteritis resulting rom ingestion of contaminated food (especially shellfish) and water? A. Norwalk-like viruses B. Rotavirus C. Hepatitis C virus D. Coronavirus
Correct Answer: A
Which virus is the most common etiological agent of viral respiratory disease infants and children? A. Respiratory syncytial virus (RSV) B. Measles virus C. Coxsackie A virus D. Coxsackie B virus
Correct Answer: A
Gram-positive bacilli recovered from two blood cultures from a 60-year-old diabetic patient gave the following results: -Spores seen=Neg -Motility=Neg -Hemolysis=+ (double zone) -Lecithinase=+ -Volatile acids by GLC (PYG)- acetic acid (A) and butyric acid (B) What is the most likely identification? A. Clostridium tetani B. Clostridium perfringens C. Clostridium novyi (B) D. Clostridium sporogenes
Correct Answer: B
Humans can serve as both the intermediate and definitive host in infections caused by: A. Enterobius vermicularis B. Hymenolepis nana C. Schistosoma japonicum D. Ascaris lumbricoides
Correct Answer: B
A gram-negative rod is recovered from a catheterized urine sample from a nursing home patient. The lactose-negative isolate tested positive for indole, urease, ornithine decarboxylase, and phenylalanime deaminase and negative for H2S. The most probable identification is: A. Edwardsiella spp. B. Morganella spp. C. Ewingella spp. D. Shigella spp.
Correct Answer: B
A gram-positive branching filamentous organism recovered from a sputum specimen was found to be positive with a modified acid-fast stain method. What is the most likely presumptive identification? A. Bacillus spp. B. Nocardia spp. C. Corynebacterium spp. D. Listeria spp.
Correct Answer: B
A helminth egg is described as having terminal polar plugs. The most likely helminth is: A. Hookworm B. Trichuris tirchiura C. Fasciola hepatica D. Diphyllobothrium latum
Correct Answer: B
In Breakpoint Antimicrobial Drug Testing, interpretation of susceptible (S), intermediate (I), and resistant (R) refers to testing antibiotics by using: A. The amount needed to cause bacteriostasis B. Only the specific concentrations necessary to report S, I, or R C. An MIC of 64 ug/mL D. A dilution of drug that is one tube less than the toxic level
Correct Answer: B
In a condition resulting from the accidental ingestion of eggs, the human becomes the intermediate rather than the definitive host. The correct answer is: A. Trichinosis B. Cysticercosis C. Ascariasis D. Strongyloidiasis
Correct Answer: B
In a patient with diarrhea, occasionally Entamoeba histolytica/E. dispar (four nucleated cysts, no chromatoidal bars) are identified as being present; however, these cells, which are misdiagnosed as protozoa, are really: A. Macrophages B. Polymorphonuclear leukocytes C. Epithelial cells D. Eosinophils
Correct Answer: B
In addition to Enterococcus faecalis, which other streptococci will grow in 6.5% slat broth? A. Group A streptococci B. Group B streptococci C. Streptococcus pneumoniae D. Group D streptococci (nonenterococci)
Correct Answer: B
In addition to motility, which test best differentiates Acinetobacter spp. and Alcaligenes spp.? A. TSI B. Oxidase C. Catalase D. Flagellar stain
Correct Answer: B
In the test for urease production, ammonia reacts to form which product? A. Ammonium citrate B. Ammonium carbonate C. Ammonium oxalate D. Ammonium nitrate
Correct Answer: B
Within the United States, sporadic mini-outbreaks of diarrheal disease have been associated with the ingestion of strawberries, raspberries, fresh basil, mesclun (baby lettuce leaves), and snow peas. The most likely causative agent is: A. Dientamoeba fragilis B. Cyclospora cayetanesis C. Schistosoma mansoni D. Cystoisospora belli
Correct Answer: B
"Clue cells" are seen on a smear of vaginal discharge obtained from an 18-year-old female emergency department patient. This finding, along with a fishy odor (amine) after the addition of 19% KOH, suggest bacterial vaginosis caused by which organism? A. Staphylococcus epidermidis B. Streptococcus agalactiae C. Gardnerella vaginalis D. E. coli
Correct Answer: C
An outbreak of Staphylococcus aureus in the nursery department prompted the Infection Control Committee to proceed with an environmental screening procedure. The best screening media to use for this purpose would be: A. CNA agar B. THIO broth C. Mannitol salt agar D. PEA agar
Correct Answer: C
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. B-Lactamase testing
Correct Answer: C
The following results were observed by using a tube coagulase test: -Coagulase at 4 hours=+ -DNase=+ -Hemolysis on blood agar=B -Coagulase at 18 hours=Neg -Novobiocin=Sensitive (16-mm zone) -Mannitol salt plate=+ (acid production) What is the most probable identification? A. Staphylococcus saprophyticus B. Staphylococcus epidermidis C. Staphylococcus aureus D. Staphylococcus hominis
Correct Answer: C
The incorrect match between organism and characteristic is: A. Chilomastix mesnili- Shepherd's crook and lemon shape B. Plasmodium malariae- "band troph" C. Hymenolepis nana- striated shell D. Wuchereria bancrofti- sheathed microfilariae
Correct Answer: C
The incorrect match between organism and the appropriate diagnostic procedure is: A. Onchocerca volvulus-examination of skin snips B. Cryptosporidium-modified acid-fast stain C. Echinococcus granulosus-routine ova and parasite examination D. Schistosoma haemotobium-examination of urine sediment
Correct Answer: C
The malonate test is most useful in differentiating which members of the Enterobacteriaceae? A. Shigella B. Proteus C. Salmonella subgroups 2, 3 ( the former Arizona) D. Serratia
Correct Answer: C
The most noted differences between P. aeruginas and Stenotrophomonas maltophlia are: A. Oxidase, catalase, TSI B. Oxidase, catalase, and ONPG C. Oxidase, 42C growth, and polar tuft of flagella D. Catalase, TSI, and pigment
Correct Answer: C
The term internal autoinfection can be associated with the following parasites: A. Crystosporidium spp. and Giardia lamblia B. Cytoisospora belli and Strongyloides stercoralis C. Cryptosporidium spp. and Strongyloides stercoralis D. Giardia lamblia and Cyroisospora belli
Correct Answer: C
There are few procedures considered STAT in parasitology. The most obvious situation would be: A. Ova and parasite examination for giardiasis B. Baermann's concentration for strongyloidiasis C. Blood films for malaria D. Culture of amoebic keratitis
Correct Answer: C
A presumptive diagnosis of Gardnerella vaginalis can be made using which of the following findings? A. Oxidase and catalase tests B. Pleumorphic bacilli heavily colonized on vaginal epithelium C. Hippurate hydrolysis test D. All of these options
Correct Answer: D
Cerebrospinal fluid (CSF) should be cultured immediately, but if delayed the specimen should be: A. Refrigerated at 4C to 6C B. Frozen at -20C C. Stored at room temperature for no longer than 24 hours D. Incubated at 37C and cultured as soon as possible
Correct Answer: D
Cold enrichment of feces (incubation at 4C) in phosphate-buffered saline prior to subculture onto enteric media enhances the recovery of: A. Enterotoxigenic E. coli B. Salmonella paratyphi C. Hafnia alvei D. Y. enterocolitica
Correct Answer: D
Colistin-nalidixic acid agar (CNA) is used primarily for the recovery of: A. Neisseria species B. Enterobacteriaceae C. Pseudomonas aeruginosa D. Staphylococcus
Correct Answer: D
Cornmeal agar wit Tween 80 is used to identify which characteristic of an unknown yeast isolate? A. Hyphae (true and pseudo) B. Blastoconidia and arthroconidia C. Chlamydospores D. All of these options
Correct Answer: D
The breakpoint of an antimicrobial drug refers to: A. The amount needed to cause bacteriostasis B. A minimum inhibitory concentration (MIC) of 16 ug/mL or greater C. A MIC of 64 ug/mL or greater D. The level of drug that is achievable in serum
Correct Answer: D
The catalase test for mycobacteria differs from that used for other types of bacteria by using: A. 1% H2O2 and 10% Tween 80 B. 3% H2O2 and phosphate buffer, pH 6.8 C. 10% H2O2 and 0.85 saline D. 30% H2O2 and 10% Tween 80
Correct Answer: D
Which of the following tests is used routinely to identify Staphylococcus aureus? A. Slide coagulase test B. Tube coagulase test C. Latex agglutination D. All of these options
Correct Answer: D
Which of the listed Pseudomonas spp. is associated with the following virulence factors: exotoxin A, endotoxins, proteolytic enzymes, antimicrobial resistance, and production of alginate? A. P. fluorescens B. P. putida C. P. stutzeri D. P. aeruginosa
Correct Answer: D
Which organism is associated with immunodeficiency syndromes and melioidosis (a glanders-like disease in Southeast Asia and northern Australia)? A. Pseudomonas aeruginosa B. Pseudomonas stutzeri C. Pseudomonas putida D. Burkholderia pseudomallei
Correct Answer: D
Which organism, associated with tuberculosis in cattle, causes tuberculosis in humans, especially in regions where dairy framing is prevalent? A. Mycobacterium avium-intracellulare complex B. Mycobacterium kansasii C. Mycobacterium marinum D. Mycobacterium bovis
Correct Answer: D
Which single test best separates Klebsiella oxytoca from K. pneumoniae? A. Urease B. Sucrose C. Citrate D. Indole
Correct Answer: D
Which species of Shigella is most commonly associated with diarrheal disease in the United States? A. S. dysenteriae B. S. flexneri C. S. boydii D. S. sonnei
Correct Answer: D
Which specimen is the least likely to provide recovery of Trichomonas vaginalis? A. Urine B. Urethral discharge C. Vaginal discharge D. Feces
Correct Answer: D
Which test are most appropriate to differentiate between Psudomonas aeruginosa and Pseudomonas putida? A. Oxidase, motility, pyoverdin B. Oxidase, motility, lactose C. Oxidase, ONPG, DNase D. Mannitol, nitrate reduction, growth at 42C
Correct Answer: D
Which test is used to differentiate the viridans streptococci form the group D streptococci and enterococci? A. Bacitracin disk test B. CAMP test C. Hippurate hydrolysis test D. Bile esculin test
Correct Answer: D
Which trichophyton species causes the favus type of tinea capitis seen in the Scandinavian countries and in the Appalachian region of the United States? A. T. verrucosum B. T. violaceum C. T. tonsurans D. T. schoenleinii
Correct Answer: D
Which virus is associated with venereal and respiratory tract warts and produces lesion of skin and mucous membranes? A. Polyomavirus B. Poxvirus C. Adenovirus D. Papillomavirus
Correct Answer: D
While on a 7-day cruise to Vancouver and Alaska a number of passengers reported to the ship's medical staff complaining of vomiting and diarrhea. Which id the most likely virus to have infected these mainly adult passengers? A. Rotavirus B. Parainfluenza C. Respiratory syncytial D. Norwalk or Norwalk-like viruses
Correct Answer: D
Why might it be necessary for both pink (lactose-positive) and colorless (lactose-negative) colonies from an initial stool culture on MacConkey agar to be subcultured and tested further for possible pathogens? A. Most Shigella strains are lactose positive B. Most Salmonella strains are maltose negative C. Most Proteus spp. are lactose negative D. Pathogenic E. coli can be lactose positive or lactose negative
Correct Answer: D
Characteristics of the rhaditiform (noninfective) larvae of Stronglyoides stercoralis include a: A. Short buccal capsule and large genital primordium B. Long buccal capsule and pointed tail C. Short buccal capsule and small genital primordium D. Small genital primordium and notch in tail
Correct Answer: A
Many a-hemolytic streptococci recovered form a wound were found to be penicillin resistant. Given the following results, what is the most likely identification? -Bile esculin=+ -Hippurate hydrolysis=+ -SXT=Resistant -PYR=+ -Bile solubility=Neg -6.5% salt=+ A. Enterococcus faecalis B. Streptococcus pneumoniae C. Streptococcus bovis D. Group B streptococci
Correct Answer: A
Mycobacteria isolated from the hot water system of a hospital grew at 42C. Colonies on Lowenstain-Jensen medium were not pigmented after exposure to light and were negative for niacin accumulation and nitrate reduction. The most likely identification is: A. Mycobacterium xenopi B. Mycobacterium marinum C. Mycobacterium ulcerans D. Mycobacterium haemophilum
Correct Answer: A
Older developting stages (trophs, schizonts) of the fifth human malaria, Plasmodium knowles, resemble those of: A. Plasmodium malariae B. Plasmodium ovale C. Plasmodium falciparum D. Plasmodium vivax
Correct Answer: A
A Gram stain from a gum lesion showed what appeared to be amoebae. A trichrome smear showed amoebae with a single nucleus and partially digested PMNs. The correct identification is: A. Trichomonas tenax B. Entamoeba histolytica/E. dispar C. Entamoeba gingivalis D. Entamoeba polecki
Correct Answer: C
Eye infections with Acanthamoeba spp. have most commonly been traced to: A. Use of soft contact lenses B. Use of hard contact lenses C. Use of contaminated lens care solutions D. Failure to remove lenses while swimming
Correct Answer: C
Haemophilus species that require the V factor (NAD) are easily recovered on which primary agar plate? A. Blood agar made with sheep red cells B. Blood agar made with horse red cells C. Chocolate agar D. Xylose agar
Correct Answer: C
In infections with Taenia solium, humans can serve as the: A. Definitive host B. Intermediate host C. Either the definitive or the intermediate host D. None of these options
Correct Answer: C
Individuals showing a positive purified protein derivative (PPD) skin test for M. tuberculosis are usually: A. Infective B. Symptomatic of pulmonary disease C. Latently infected D. Falsely positive
Correct Answer: C
Ingestion of which of the following eggs will result in infection? A. Strongyloides stercoralis B. Schistosoma japonicum C. Toxocara canis D. Opisthrochis sinensis
Correct Answer: C
Lysine iron agar (LIA) showing a purple slant and a blackened butt indicates: A. E. coli B. Citrobacter spp. C. Salmonella spp. D. Proteus spp.
Correct Answer: C
Lysostaphin is used to differentiate Staphylococcus from which other genus? A. Streptococcus B. Stomatococcus C. Micrococcus D. Planococcus
Correct Answer: C
Which of the following amino acids are required for growth of Francisella tularensis? A. Leucine and ornithine B. Arginine and lysine C. Cysteine and cystine D. Histidine and tryptophan
Correct Answer: C
Which of the following test should be done first in order to differentiate Aeromonas spp. from the Enterobacteriaceae? A. Urease B. OF glucose C. Oxidase D. Catalase
Correct Answer: C
Which of the following Mycobacterium species is diagnosed by means other than culture? A. M. leprae B. M. bovis C. M. canetti D. M. avium
Correct Answer: A
Which of the following Mycobacterium spp. produce(s) pigmented colonies in the dark (is a scotochromogen)? A. M. szulgai B. M. kansasii C. M. tuberculosis D. All of these options
Correct Answer: A
Which of the following Mycobacterium spp. would be most likely to grow on a MacConkey agar plate? A. M. chelonae-fortuitum complex B. M. ulcerans C. M. marinum D. M. avium-intracellulare complex
Correct Answer: A
Which of the following is a characteristic of strains of Haemophilus influenzae that are resistant to ampicillin? A. Production of B-lactamase enzyme B. Hydrolysis of chloramphenicol C. Hydrolysis of urea D. All of these options
Correct Answer: A
Xylose lysine deoxycholate (XLD) agar is a highly selective medium used for the recovery of which bacteria? A. Staphylococcus spp. from normal flora B. Yersinia spp. that do not grow on Hektoen agar C. Enterobacteriaceae from gastrointestinal specimens D. Streptococcus spp. from stool cultures
Correct Answer: C
Which of the following variables may change the results of an MIC? A. Inoculum size B. Incubation time C. Growth rate of the bacteria D. All of these options
Correct Answer: D
Which microfilariae are usually not found circulating in the peripheral blood? A. Brugia malayi B. Wuchereria bancrofti C. Onchocerca volvulus D. Loa Loa
Correct Answer: C
Which of the following Mycobacterium spp. is best differentiated by the rapid hydrolysis of Tween 80? A. M. fortuitum B. M. chelonae C. M. kansasii D. M. gordonae
Correct Answer: C
Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions occur with: A. E. coli B. Salmonella spp. C. Pseudomonas spp. D. Proteus spp.
Correct Answer: A
Which of the following organism are generally positive for B-galactosidase? A. Salmonella spp. B. Shigella spp. C. Proteus spp. D. E. coli
Correct Answer: D
The most sensitive method for the detection of B-lactamase in bacteria is by the use of: A. Chromogenic cephalosporin B. Penicillin C. Oxidase D. Chloramphenicol acetyltransferase
Correct Answer: A
The mycelial form of Histoplasma capsulatum seen on agar resembles: A. Sepedonium spp. B. Penicillium spp. C. Sporothrix spp. D. Coccidiodes spp.
Correct Answer: A
Ascospores are formed by which yeast isolate? A. Saccharomyces cerevisiae B. Candida albicans C. Cryptococcus neoformans D. All of these options
Correct Answer: A
Blastoconidia are the beginning of which structures? A. Arthroconidia B. Germ tubes C. Pseudohyphae D. True hyphae
Correct Answer: C
Yeast recovered form the urine of a catheterized patient receiving chemotherapy for cancer gave the fllowing results: Cornmeal Tween 80 agar -Germ tube=+ -Pseudohyphae=+ -Blastoconidia=+ -Arthroconidia=Neg -Chlamydospores=+ What further testing is necessary? A. Carbohydrate assimilation and urease B. Urease and niger seed C. Nitrate reductase and carbohydrate fermentation D. No further testing is needed for identification
Correct Answer: D
SITUATION: Abdominal pain, fever, vomiting, and nausea prompted an elderly male to seek medical attention. A water stool specimen producing no fecal leukocytes or erythrocytes was cultured and grew a predominance of gram-negative fermentative bacilli. The colonies were beta-hemolytic on blood agar and cream colored on MacConkey agar. The colonies were both oxidase and catalase positive. What is the most likely identification? A. Aeromonas hydrophilia B. Escherichia coli C. Salmonella spp. D. Shigella spp.
Correct Answer:A
Which of the following organisms is the cause of Lyme disease? A. Treponema pallidum B. Neisseria meningitidis C. Babesia microti D. Borrelia burgdorferi
Correct Answer: D
Which of the following structures is invaded by the genus Trichophyton? A. Hair B. Nails C. Skin D. All of these options
Correct Answer: D
The Superoxol test is used as a rapid presumptive test for: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Neisseria lactamica D. Moraxella (Branhamella) catarrhalis
Correct Answer: A
The Voges-Proskauer (VP) test detects which end product of glucose fermentation? A. Acetoin B. Nitrite C. Acetic acid D. Hydrogen sulfide
Correct Answer: A
The adult tapeworm of Echinococcus granulosus is found in the intestine of: A. Dogs B. Sheep C. Humans D. Cattle
Correct Answer: A
Large gram-positive spore-forming rods growing on blood agar as large, raised, B-hemolytic colonies that spread and appear as frosted green-gray glass are most likely A. Pseudomonas spp. B. Bacillus spp. C. Corynebacterium spp. D. Listeria spp.
Correct Answer B
The best specimen for recovery of the mycobacteria from a sputum sample is: A. First morning specimen B. 10-hour evening specimen C. 12-hour pooled specimen D. 24-hour pooled specimen
Correct Answer: A
A 1-month-old infanct underwent a spinal tap to rule out bacterial meningitis. The CSF was cloudy, and the smear showed many pus cells and short gram-positive rods. After 18 hours, many colonies appeared on blood agar that resembled Streptococcus spp. or L. monocytogenes. Which of the following preliminary tests should be performed on the colonies to best differentiate L. monocytogenes from Streptococcus spp.? A. Hanging-drop motility (25C) and catalase B. PYR and bacitracin C. Oxidase and glucose D. Coagulase and catalase
Correct Answer: A
The diagnostic method most commonly used for the identification of Lyme disease is: A. Serology B. Culture C. Gram stain D. Acid-fast stain
Correct Answer: A
A 14-year-old emergency department patient had been tothe doctor's office 2 days previously with abdominal pain, diarrhea, and a low-grade fever. He was diagnosed with pseudoappendicular syndrome. Cultures form the stool containig blood and WBCs showed the following results: AEROBIC GRAM-NEGATIVE RODS ON MACONKEY AGAR (CLEAR COLONIES) -Campy agar=No growth -Lactose=Neg -Indole=Neg -Motility 37C=Neg -Sucrose=+ -VP=Neg -Motility 22C=+ -Citrate=Neg -H2S=Neg -Hektoen agar=NF What is the most likely identification? A. Yersinia enterocolitica B. Salmonella spp. C. Shigella spp. D. Escherichia coli
Correct Answer: A
A 20-year-old female patient entered the emergency clinical complaining of abdominal pain fever, and a burning sensation during urination. An above-normal WBC count along with pus cells ad bacteria in the urine specimen prompted the emergency physician to order a urine culture. The colony count reported for this patient revealed >100,000 col/mL of a nonhemolytic, catalase-negative, gram-positive organisms on 5% sheep blood agar. The following test results indicated which organism? A. Enterococcus faecalis B. Streptococcus pyogenes C. Streptococcus agalactiae D. Streptococcus bovis
Correct Answer: A
A 20-year-old horse groomer exhibited a "glanders-like" infection. His history indicated he had suffered several open wounds on his hands 2 weeks before the swelling of his lymph nodes. A gram-negative rod was recovered rom a blood culture that grew well on blood and MacConkey agars. Most of the biochemical tests were negative, including the cytochrome oxidase test. What is the most likely identification? A. Burkholderia mallei B. Pseudomonas aeruginosa C. Pseudomonas stutzeri D. Burkholderia pseudomallei
Correct Answer: A
A 22-year-old pregnant woman (third trimester) entered the emergency department complaining of diarrhea, fever, and other flulike symptoms. Blood cultures were ordered along with a urine culture. After 24 hours, the urine culture was negative, but the blood cultures revealed a gram-positive short rod that grew aerobically on blood agar. The colonies were small and smooth, resembling a Streptococcus spp. with a small narrow zone of B-hemolysis. The following test results indicate which organism? -Motility=+ (Wet mount= Tumbling) -Glucose=+ (Acid) -Catalase=+ -Esculin hydrolysis=+ A. Listeria monocytogenes B. Streptococcus pneumoniae C. Streptococcus agalactiae D. Corynebacterium spp.
Correct Answer: A
A 30-year-old male patient who was a contractor and building inspector in the southwestern United States complained of difficulty breathing and was admitted to the hospital with sever respiratory disease. The physician noted a high fever and cough. Two days before, the patient had inspected an old warehouse, abandoned and infested with rodents. The patient was given intravenous antibiotics, but 2 days into therapy the pneumonia worsened and he developed pulmonary edema. Which organism should be suspected of causing his illness? A. Hantavirus B. Rotavirus C. West Nile virus D. Norwalk-like virus
Correct Answer: A
A 40-year-old female experienced a respiratory infection after returning home form a visit to her homeland of China. A rapid onset of pneumonia in the lower respiratory area prompted the physician to place her in isolation. She was diagnosed presumptively with severe acute respiratory syndrome (SARS) and placed on a respirator. What type of testing should be done next to diagnose this disease? A. Molecular technique and cell culture B. Latex agglutination test C. Blood culture D. Complement fixation
Correct Answer: A
A 46-year-old dog warden was admitted to the hospital with several puncture bite wounds encountered while wrangling with a stray dog. Culture at 48 hours produced small yello colonies on 5% sheep blood and chocolate agars in 10% CO2, but no growth on MacConkey agar. Gram stain showed gram0negative curved, fusiform rods. Colonies were oxidase and catalase positive. What is the most likely identification? A. Capnocytophaga canimorsus B. Francisella tularensis C. Legionella pneumophila D. Pseudomonas aeruginosa
Correct Answer: A
A 50-year-old male transplant patient was experiencing neurological difficulties after a pulmonary infection. A spinal tap revealed a cloudy CSF with a Gram-stained smear revealing gram-positive long-beaded bacilli. An acid-fast smear showed filamentous partially acid-fast bacilli. What is the most likely identification of the organism? A. Nocardia asteroides B. Mycobacterium avium C. Mycobacterium bovis D. Legionella spp.
Correct Answer: A
A 6-month-old male infant was hospitalized with a respiratory infection. He was diagnosed with apnea and bronchiolitis. Further testing revealed congenital hear disease. Bacterial cultures were negative for Streptococcus pneumoniae and Haemophilus influenzae. What further testing should be done? A. Respiratory syncytial virus (RSV) B. Rotavirus C. Norwalk virus D. HIV
Correct Answer: A
A 60-year-old male garderner form New York State was hospitalized with flulike symptoms and eventually idanosed with encephalitis. While working in his garden, he noticed several dead birds around his bird feeder. The region was known to be heavily infested with mosquitoes. What is the most likely cause of his illness? A. West Nile virus B. Epstein-Barr virus C. Parvovirus D. Hantavirus
Correct Answer: A
A Gram stain of a urethral discharge form a man showing extracellular and intracellular gram-negative diplococci within segmented neutrophils is a presumptive identification for: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Moraxella (Branhamella) catarrhalis D. Neisseria lactamica
Correct Answer: A
A blood agar plate inoculated with sputum from a patient with diabetes mellitus grew very few bacterial flora and predominance of yeast. Given the following results, what is the most likely identification of the yeast isolate? Cornmeal Tween 80 Agar -Germ tube=Neg -Arthroconidia=Neg -Chlamydospores=Neg -Pseudohyphae=+ -Blastoconidia=+ (arranged along pseudohyphae) A. Candida tropicalis B. Candida kefyr (pseudotropicalis) C. Trichosporon cutaneum D. Geotrichum candidum
Correct Answer: A
A bloody stool cultured from a 26-year-old woman after 3 days of severe diarrhea showed the following results at 48 hours after being plated on the following media: -MacConkey agar: little normal flora with many non-lactose-fermenting colonies -Hektoen enteric agar: many blue-green colonies -Campylobacter blood agar and C. difficile agar: no growth -Clear colonies (from MacConkey agar) tested negative for oxidase, indole, urease, motility, and H2S A. Shigella spp. B. Salmonella spp. C. Proteus spp. D. E. coli
Correct Answer: A
The drugs of choice for treatment of infections with Enterobacteriaceae are: A. Aminoglycosides, trimethoprim-sulfamethoxazole, third-generation cephalosporins B. Ampicillin and nalidixic acid C. Streptomycin and isoniazid D. Chloramphenicol, ampicillin, and colistin
Correct Answer: A
A bone marrow sample obtained form an immunocompromised patient revealed small intracellular cells using a Wright's stain preparation. Growth on Sabouraud-dextrose agar plates of a mold phase at 25C and a yeast phase at 37C designates the organism as dimorphic. The mold phase produced thick, spherical tuberculated macroconidia. What is the most likely identification? A. Histoplasma capsulatum B. Sepedonium spp. C. Sporothrix schenckii D. Coccidioides immitis
Correct Answer: A
A catalase-positive, gram-positive short rod was recovered form the blood of a prenatal patient. The organism appeared on 5% sheep blood as white colonies surrounded by a small zone of beta-hemolysis. The following tests were performed, indicating the patient was infected with which organism? -Motility=+ (rumbling on wet prep) room temperature -Motility=+ (umbrella-shape on semisolid agar) room temperature -Glucose=+ (fermentation) -Esculin=+ -Voges-Proskauer=+ A. Listeria monocytogenes B. Streptococcus agalactiae C. Streptococcus pyogenes D. Lactobacillus spp.
Correct Answer: A
A culture from an intra-abdominal abscess produced orange-tan colonies on blood agar that gave the following results; -Oxidase=+ -KIA=Alk/Alk (H2S) -DNase=+ -Growth at 42C=Neg -Nitrate reduction=+ -Motility=+ (single polar flagellum) -Ornithine decarboxylase=+ The most likely identification is: A. Shewanella putrefaciens B. Acinetobacter spp. C. Pseudomonas aeruginosa D. Chryseobacterium spp.
Correct Answer: A
A dehydrated 25-year-old male patient was admitted to the hospital with symptoms similar to those of chronic fatigue syndrome. Serological testing proved negative for recent streptotococcal infection, Epstein-Barr virus, and hepatitis. Which of the following viral serological tests should help with a possible diagnosis? A. CMV B. Echovirus C. Respiratory syncytial virus D. Measles virus
Correct Answer: A
A direct smear form a nasopharyngeal swab stained with Loeffler methylene blue stain showed various letter shapes and deep blue, metachromatic granules. The most likely identification is A. Corynebacterium spp. B. Nocardia spp. C. Listeria spp. D. Gardnerella spp.
Correct Answer: A
A false-positive CAMP test for the presumptive identification of group B streptococci may occur if the plate is incubated in a(n): A. Candle jar or CO2 incubator B. Ambient air incubator C. 35C incubator D. 37C incubator
Correct Answer: A
A fourfold rise in titer of which antibody is the best indicator of a recent infection with group A B-hemolytic streptococci? A. Anti-streptolysin O B. Anti-streptolysin S C. Anti-A D. Anti-B
Correct Answer: A
A hyaline mold recovered form a patient with AIDS produced rose-colored colonies with lavender centers on Sabouraud dextrose agar. Microscopic examination showed multiseptate macroconidia appearing as sickles or canoes. What is the most likely identification> A. Fusarium spp. B. Wangiella spp. C. Exophiala spp. D. Phialophora spp.
Correct Answer: A
A laboratory provides the following services for identification of mycobacteria: -Acid-fast staining of clinical specimens -Inoculation of cultures -Shipment of positive cultures to a reference laboratory for identification According to the American Thoracic Society's definition for levels of service this laboratory is: A. Level I B. Level II C. Level III D. Level IV
Correct Answer: A
A lung biopsy obtained from an immunocompromised patient showed many "cup-shaped" cysts (gray to black) in a foamy exudate (green background) using Gomori methenamine silver (GMS) stain. the organism cannot be cultured because it does not grow on routine culture media for molds. The patient was routine culture media for molds. The patient was diagnosed with pneumonia that resisted antibiotic treatment. The most likely identification is? A. Pneumocystis jirovecci (carinii) B. Histoplasma capsulatum C. Sporothrix schenckii D. Scopulariopsis spp.
Correct Answer: A
A mixture of slender gram-negative rods and coccobacilli with rounded ends was recovered from blood cultures following a patient's root canal surgery. Given the following results after 48 hours, what is the most likely organism? -Catalase=Neg -Urease=Neg -Oxidase=+ -Indole=Neg -Ornithine decarboxylase=+ -Lysin decarboxylase=+ -X and V requirement=Neg -Carbohydrates=Neg (no acid produced) -Growth on blood and chocolate agar=+ (with pitting of agar) -Growth on MacConkey agar=Neg A. Eikenella corrodens B. Actinobacillus spp. C. Cardiobacterium hominis D. Proteus spp.
Correct Answer: A
A mold that produces colonies with a dark brown, green-black, or black appearance of both the surface and reverse side is classified as a: A. Dematiaceous mold B. Dermatophyte C. Hyaline mold D. Dimorphic fungus
Correct Answer: A
A non-spore-forming, slender gram-positive rod forming palisades and chains was recovered from a vaginal culture and grew well on tomato juice agar. The most likely identification is: A. Lactobacillus spp. B. Bacillus spp. C. Neisseria spp. D. Streptococcus spp.
Correct Answer: A
A nonfermenter recovered form an eye wound is oxidase positive, motile with polas monotrichous flagell, and grows at 42C. Colonies are dry, wrinkled or smooth, buff to light brown in color, and are difficult to remove from the agar. In which DNA homology group should this organism be placed? A. Pseudomonas stutzeri B. Pseudomonas fluorescens C. Pseudomonas alcaligenes D. Pseudomonas diminuta
Correct Answer: A
A patient has been diagnosed as having amebiasis but continues to be asymptomatic. The physician has asked for an explanation and recommendations regarding follow-up. Suggestions should include: A. Consideration of Entamoeba histolytica versus Entamoeba dispar B. A request for an additional three stools for culture C. Initiating therapy, regardless of the patient's asymptomatic status D. Performance of barium x-ray studies
Correct Answer: A
A positive Simmons citrate test is seen as a: A. Blue color in the medium after 24 hours of incubation at 35C B. Red color in the medium after 18 hours of incubation at 35C C. Yellow color in the medium after 24 hours of incubation at 35C D. Green color in the medium after 18 hours of incubation at 35C
Correct Answer: A
An Entamoeba histolytic trophozoite has the following characteristics: A. Central karyosome in the nucleus, ingested RBCs, and clear pseudopodia B. Ingested RBCs, clear pseudopodia, and uneven chromatin on the nuclear membrane C. Ingested RBCs, clear pseudopodia, and large glycogen vacuoles in cytoplasm D. large, blotlike karyosome, ingested white blood cells (WBCs), and granular pseudopods
Correct Answer: A
A presumptive diagnosis of gonorrhea can be made from an exudate from a 20-year-old emergency department patient if which of the following criteria are present? A. Smear of urethral exudate (male only) shoes typical gram-negative, intracellular diplococci; growth of oxidase-positive, gram-negative diplococci on selective agar (modified Thayer-Martin) B. Smear from vaginal area shows gram-negative diplococci; growth of typical colonies on blood agar C. Smear from rectum shows typical gram-negative diplococci; no growth on chocolate agar D. Growth of gram-negative cocci on MacConkey agar and blood agar
Correct Answer: A
A rapidly growing nonseptate mold produced colonies with a gray surface resembling cotton candy that covered the entire plate. Microscopic examination revealed sporangiophores arising between, not opposite, the rhizoids and producing pear-shaped sporangia. what is the most likely identification? A. Absidia spp. B. Penicillium spp. C. Rhizopus spp. D. Aspergillus spp.
Correct Answer: A
A routine, complete stool culture procedure should include media for the isolation of E. coli 0157:H7 as well as: A. Salmonella, Shigella, Yersinia, Campylobacter, and Staphylococcus aureus B. Vibrio cholerae, Brucella, and Yersinia spp. C. S. aureus, group B streptococci, and group D streptococci D. Clostridium difficile, Clostridium perfringens, and Yersinia spp.
Correct Answer: A
A sputum culture from a 13-year-old cystic fibrosis patient grew a predominance of short, gram-negative rods that tested oxidase negative. On MacConkey, chocolate, and blood agar plates, the organism appeared to have a lavender-green pigment. Further testing showed: -Motility=+ -Glucose=+ (oxidative) -Lysine decarboxylase=+ -DNase=+ -Maltose=+ (oxidative) -Esculin hydrolysis=+ What is the most likely identification? A. Stenotrophomonas maltophilia B. Acinetobacter baumannii C. Pseudomonas aeruginosa D. Burkholderia (P.) cepacia
Correct Answer: A
A stool culture from a 30-year-old man suffering from bloody mucoid diarrhea gave the following results on differential enteric media: -MacConkey agar=clear colonies; -XLD agar=clear colonies -Hektoen agar=green colonies -Salmonella-Shigella agar=small, clear colonies Which tests are most appropriate for identification of this enteric pathogen? A. TSI, motility, indole, urease, Shigella typing with polyvalent sera B. TSI, motility, indole, lysine, Salmonella typing with polyvalent sera C. TSI, indole, MR, VP, citrate D. TSI, indole, MR, and urease
Correct Answer: A
A suspected Bacillus antrhacis culture obtained from a wound specimen produced colonies that had many outgrowths (Medusa-head appearance), but were not B-hemolytic on sheep blood agar. Which test should be performed next? A. Penicillin (10-unit) susceptibility test B. Lecithinase test C. Glucose test D. Motility test
Correct Answer: A
A thermally dimorphic fungus shows a filamentous mold form with tuberculate macroconidia at room temperature, and a yeast form above 35C. Which organism best fits this description? A. Histoplasma capsulatum B. Paracoccidioides brasiliensis C. Candida albicans D. Coccidioides immitis
Correct Answer: A
A vancomycin-resistant gram-positive coccobacillus resembling the Streptococcus viridans group was isolated form the blood of a 42-year-old female patient undergoing a bone marrow transplant. The PYR and leucine aminopeptidase (LAP) tests were negative. The following results were noted: -Catalase=Neg -Esculin hydrolysis=Neg -Hippurate hydrolysis=Neg -CAMP=Neg -Gas form glucose=+ -6.5% salt broth=Neg What is the correct identification? A. Leuconostoc spp. B. Enterococcus spp. C. Staphylococcus spp. D. Micrococcus spp.
Correct Answer: A
A young male patient with a fungus of the feet visited the podiatris for relief form the itching. A culture was sent to the microbiology laboratory that grew after 8 days on Sabouraud dextrose agar. Colonies were powdery pink with concentric and radial folds, with the reverse side showing brownish-tan to red in color. Other obsevations were: -Hyphae=Septate -Macroconidia=Cigar shaped, thin walled with 1-6 cells -Microconidia=Round and clustered on branched conidiophores -Red pigment on cornmeal (1% dextrose)=Neg -In vitro hair perforation=+ -Urease=+ The most likely identification is: A. Trichophyton mentagrophytes B. Trichophyton rubrum C. Candida albicans D. Aspergillus niger
Correct Answer: A
According to the Kirby-Bauer standard antimicrobial susceptibility testing method, what should be done when interpreting the zone size of a motile, swarming organism such as a Proteus species? A. The swarming are should be ignored B. The results of the disk diffusion method are invalid C. The swarming area should be measured as the growth boundary D. The isolate should be retested after diluting to a 0.05 McFarland standard
Correct Answer: A
According to the reporting standards of the American Thoracic Society, one or more acid-fast bacilli (AFB) per oil immersion field (1,000X) are reported as: A. Numerous or 3+ B. Few or 2+ C. Rare or 1+ D. Indeterminate; a new specimen should be requested
Correct Answer: A
Acid-fast positive bacilli were recovered form the sputum of a 79-year-old man who had been treated for pneumonia. Which of the following test reaction after 3 weeks of incubation on Lowenstein-Jensen agar are consistent with Mycobacterium tuberculosis? A. Niacin=+; Nitrate reduction=+; Photochromogenic=Neg B. Niacin=+; Optochin=+; Catalase=+ C. PYR=+; Urease=+; Bacitracin=+ D. Ampicillin=Resistant; Penicillin=Resistant;
Correct Answer: A
Acid-fat staining of a smear prepared from digested sputum showed slender, slightly curved, beaded, red mycobacterial rods. Growth on Middlebrook 7H10 slants produced buff-colored microcolonies with a serpentine pattern after 14 days at 37C. Niacin and nitrate reduction tests were positive. What is the most probable presumptive identification? A. Mycobacterium tuberculosis B. Mycobacterium ulcerans C. Mycobacterium kansasii D. Mycobacterium avium-intracellulare complex
Correct Answer: A
Alcaligenes faecalis (formerly A. odorans) is distinguished from Bordetella bronchiseptica with which test? A. Urease (rapid) B. Oxidase C. Growth on MacConkey agar D. Motility
Correct Answer: A
An 80-year-old male patient was admitted to the hospiral with a fever of 102F. A sputum culture revealed many gram-negative rods on MacConkey agar and blood agar. The patient was diagnosed with pneumonia. The following biochemical results were obtained form the culture: -H2S=Neg -Citrate=+ -Motility=Neg -Lactose=+ -Indole=+ -Resistance to ampicillin and carbenicillin -Urease=+ -VP=+ What is the most likely identification? A. Klebsiella oxytoca B. Proteus mirabilis C. Escherichia coli D. Klebsiella pneumoniae
Correct Answer: A
An elderly woman who cared for several domestic cats was hospitalized with suspected cat-scratch disease (CSD). Blood culture appeared negative, bur a small, slightly curved pleomorphic gram0negative bacillus grew on BHI agar (brain, hear infusion agar with 5% horse or rabbit blood). What is the most likely identification? A. Bartonella spp. B. Brucella spp. C. Kingella spp. D. Haemophilus spp.
Correct Answer: A
An emergency department physician ordered a culture and sensitivity test on a catheterized urine specimen obtained from a 24-year-old female patient. A colony count was done and gave the following results after 24 hours: -Blood agar plate=>100,000 col/mL of gram-positive cocci resembling staphylococci -MacConkey agar=No growth -Hemolysis=Neg -Novobiocin=Resistant -CNA plate=Inhibited growth -Catalase=Positive A. Staphylococcus saprophyticus B. Micrococcus luteus C. Staphylococcus aureus D. Streptococcus pyogenes
Correct Answer: A
An immunocompromised patient was admitted to the hospital with a diagnosis of hemorrhagic cystitis. Which combination of virus and specimen would be most appropriate to diagnose a viral cause of this disorder? A. BK virus-urine B. Human papilloma virus-skin C. Hepatitis B virus-serum D. Epstein-Barr virus-serum
Correct Answer: A
An immunocompromised patient with prior antibiotic treatment grew aerobic gram-positive cocci from several clinical specimens that were culture. The organism was vancomycin resistant and catalase negative. Additional testing proved negative for enterococci. What other groups of organism might be responsible? A. Leuconostoc spp. and Pediococcus spp. B. Streptococcus pyogenes and Streptococcus agalactiae C. Micrococcus spp. and Genella spp. D. Clostridium spp. and Streptococcus bovis
Correct Answer: A
An isolate from CSF growing on cornmeal agar produces the following structures: -Blastoconidia=+ -Chlamydospores=Neg -Pseudohyphae=Neg -Arthroconidia=Neg Which test should be performed next? A. Birdseed agar and urease B. Germ tube and glucose C. India ink and germ tube D. All of these options
Correct Answer: A
An isolate of E. coli recovered form the stool of a patient with severe bloody diarrhea should be tested for which sugar before sending it to a reference laboratory for serotyping? A. Sorbitol (fermentation) B. Mannitol (oxidation) C. Raffinose (fermentation) D. Sucrose (fermentation)
Correct Answer: A
An isolate produced a constriction that was interpreted as a positive germ tube, but Candida albicans was ruled out when confirmatory tests were performed. Which of the following fungi is the most likely identification? A. Candida tropicalis B. Cryptococcus neoformans C. Candida glabrata D. Rhodotorula rubra
Correct Answer: A
An organism cultured from the skin produces colonies displaying a cherry-red color on Sabouraud dextrose agar after 3-4 weeks and teardrop-shaped microconidia along the side of hyphae. The most likely identification is: A. Trichophyton rubrum B. Trichophyton tonsurans C. Trichophyton schoenleinii D. Trichophyton violaceum
Correct Answer: A
Anaerobic gram-positive bacilli with subterminal spores were rocvered from several blood cultures obtained from a patient diagnosed with a malignancy of the colon. The following results were recorded: -Indole=Neg -Catalase=Neg -Urease=Neg -Lecithinase=Neg -Lipase=Neg -Growth on blood agar=Swarming colonies What is the correct identification? A. Clostridium septicum B. Clostridium perfrigens C. Clostridium sordellii D. Propionibacterium acnes
Correct Answer: A
Anaerobic, nonpigmented, gram-negative rods were recovered from an anaerobic blood agar plate after 48 hours of incubation. The Gram-stained smear showed thin bacilli with pointed ends. The colonies on blood agar had the appearance of dry, irregular, white breadcrumb-like morphology with greening of the agar. The following reactions were noted: -Kanamycin=Sensitive -Colistin=Sensitive -Indole=+ -Lipase=Neg -Vancomycin=Resistant -Nitrate=Neg -Catalase=Neg -Urease=Neg -Growth on 20% bile agar=Neg What is the correct identification/ A. Fusobacterium nucleatum B. Bacteroides fragilis C. Clostridium perfringens D. Peptostreptococcus spp.
Correct Answer: A
Babesia has been implicated in disease from both splenectomized and nonsplenectomized patients. Morphologically, the parasites resemble: A. Plasmodium falciparum rings B. Leishmania donovani amastigotes C. Trypanosoma cruzi trypomatigotes D. Microsporidial spores
Correct Answer: A
Bacillus anthracis and Bacillus cereus can best be differentiate by which test? B-hemo; motility; oxidase; catalase; lecithinase; glucose B.cereus: +; +; Neg: +; +; + B.anthracis: Neg; Neg; Neg: +; +; + A. Motility and B-hemolysis on a blood agar plate B. Oxidase and B-hemolysis on a blood agar plate C. Lecithinase and glucose D. Lecithinase and catalase
Correct Answer: A
Bacitracin A disk (0.04 unit) are used for the presumptive identification of which group of B-hemolytic streptococci? A. Group A B. Group B C. Group C D. Group F
Correct Answer: A
Bacitracin resistance (0.04 unit) is used to differentiate: A. Micrococcus spp. from Staphylococcus spp. B. Staphylococcus spp. for Neisseria spp. C. Planococcus spp. from Micrococcus spp. D. Staphylococcus spp. from Streptococcus spp.
Correct Answer: A
Biochemically, the Enterobacteriaceae are gram-negative rods that: A. Ferment glucose, reduce nitrate to nitrite, and are oxidase negative B. Ferment glucose, produce indophenol oxidase, and form gas C. Ferment lactose and reduce nitrite to nitrogen gas D. Ferment lactose and produce indophenol oxidase
Correct Answer: A
Carbohydrate assimilation tests are used for the identification of yeast isolates by inoculating media: A. Free of carbohydrates B. Free of niger seed C. Containing carbohydrates D. Containing yeast extract
Correct Answer: A
Chryseobacterium spp. and B. cepacia are easily differentiated by which test? A. Motility B. OF glucose C. Oxidase D. Cetrimide agar
Correct Answer: A
Chryseobacterium spp. are easily distinguished from Acinetobacter spp. by which of the following two tests? A. Oxidase, growth on MacConkey agar B. Oxidase and OF (glucose) C. TSI and urea hydrolysis D. TSI and VP
Correct Answer: A
The L-pyrrolidonyl-B-napthylamide (PYR) hydrolysis test is a presumptive test for which streptococci? A. Group A and D (enterococcus) streptococci B. Group A and B B-hemolytic streptococci C. Nongroup A or B B-hemolytic streptococci D. Streptococcus penumoniae and group D streptococci (nonenterococcus)
Correct Answer: A
Culture of a skin (hand) wound from a manager of a tropical fish store grew on Lowenstein-Jensen agar slants at 30C in 10 days but did not grow on the same media at 37C in 20 days. Given the following results, what is the most likely identification? -Photochromogen=+ -Heat-stable catalase (68C)=Neg -NItrate reduction=Neg -Niacin=Neg -Urease=+ -Tween 80 hydrolysis A. Mycobacterium marinum B. Mycobacterium kansasii C. Mycobacterium avium-intracellulare complex D. Mycobacterium tuberculosis
Correct Answer: A
Deoxycholate agar (DCA) is useful for the isolation of: A. Enterobacteriaceae B. Enterococcus spp. C. Staphylococcus spp. D. Neisseria spp.
Correct Answer: A
During the summer break, several middle-aged elementary school teachers from the same school district attended a 3-day seminar in Chicago. Upon returning home, three female teachers form the group were hospitalized with pneumonia, flulike symptoms, and a nonproductive cough. Routine testing of sputum samples revealed normal flora. Further testing using buffered CYE agar with L-cysteine and a-ketoglutarate in 5% CO2 produced growth of opaque colonies that stained faintly, showing thin gram-negative rods. What is the most likely identification? A. Legionella pneumophila B. Haemophilus influenzae C. Eikenella corrodens D. Streptococcus pneumoniae
Correct Answer: A
Eating poorly cooked pork can lead to an infection with: A. Taenia solium and Trichinella spiralis B. Taenia saginata and Hymenolepis nana C. Trichuris trichiura and hymenolepis diminuta D. Diphyllobothrium latum and Ascaris lumbricoides
Correct Answer: A
Egg yolk agar is used to detect which enzyme produced by Clostridium species? A. Lecithinase B. B-Lactamase C. Catalase D. Oxidase
Correct Answer: A
Enterobacter sakazakii can best be differentiated from Enterobacter cloacae by which of the following characteristics? A. Yellow pigmentation and negative sorbitol fermentation B. Pink pigmentation and positive arginine dihydrolase C. Yellow pigmentation and positive urease D. H2S production on TSI
Correct Answer: A
Fever, abdominal cramping, watery stools, and fluid and electrolyte loss preceded by bloody stools 2-3 days before is characteristic of shigellosis but may also result from infection with: A. Campylobacter spp. B. Salmonella spp. C. Proteus spp. D. Yersinia spp.
Correct Answer: A
Following a 2-week camping trip to the Southwest (US), a 65-year-old male patient was hospitalized with a high fever and an inflammatory swelling of the axilla and groin lymph nodes. Several blood cultures were obtained, resulting in growth of gram-negative rods resembling "closed safety pins." The organism grew on MacConkey's agar showing non-lactose-fermenting colonies. Testing demonstrated a nonmotile rod that was biochemically inert. What is the most likely identification? A. Yersinia pestis B. Klebsiella pneumoniae C. Proteus vulgaris D. Morganella morganii
Correct Answer: A
For which clinical specimens is the KOH direct mount technique for examination of fungal elements used? A. Skin B. CSF C. Blood D. Bone marrow
Correct Answer: A
Furazolidone (Furoxone) susceptibility is a test used to differentiate: A. Staphyloccus spp. from Micrococcus spp. B. Streptococcus spp. from Staphylococcus spp. C. Staphylococcus spp. from Pseudomonas spp. D. Streptococcus spp. from Micrococcus spp.
Correct Answer: A
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 israeli B. Propionibacterium acnes C. Staphylococcus intermedius D. Peptostreptococcus anaerobius
Correct Answer: A
Growth inhibition by thiophene-2-carboxylic hydrazid (T2H) is used to differentiate M. tuberculosis from which other Mycobacterium specie? A. M. bovis B. M. avium-intracellulare complex C. M. kansasii D. M. marinum
Correct Answer: A
Haemophilus influenzae causes ocular infections (pinkeye) and requires X and V factors in the primary medium for growth. The subspecies Haemophilus influenza (biogroup) aegyptius can further be identified and differentiated by which two test? A. Indole and xylose B. Glucose and urease C. Oxidase and catalase D. ALA test and oxidase
Correct Answer: A
Identify the following bacterium and specimen pairing that is mismatched (specimen not appropriate for isolation). A. Chlamydia (Chlamydophila) psittaci: fecal swab B. Chlamydia trachomatis: first voided urine C. Chlamydia trachomatis: endocervical swab D. Chlamydia pneumonia: throat swab or sputum
Correct Answer: A
In addition to CO2 requirements and biochemical characteristics, Brucella melitensis and Brucella abortus are differentiated by growth on media containing which two dyes? A. Basic fuchsin and thionin B. Methylene blue and crystal violet C. Carbol fuchsin and iodine D. Safranin and methylene blue
Correct Answer: A
In an outbreak of diarrheal disease traced to a municipal water supply, the most likely causative agent is: A. Cryptosporidium spp. B. Cystoisospora belli C. Entamoeba histolytica D. Dientamoaba fragilis
Correct Answer: A
In the United States, most blood agar plates are prepared with 5% or 10% red blood cells (RBCs) obtained from: A. Sheep B. Horses C. Humans D. Dogs
Correct Answer: A
Infections caused by Yersinia pestis are rare in the United States. Those cases that do occur are most frequently located in which region? A. New Mexico, Arizona, and California B. Alaska, Oregon, and Utah C. North and South Carolina and Virginia D. Ohio, Michigan, and Indiana
Correct Answer: A
Key characteristics of infection with Plasmodium knowlesi include: A. Rapid erythrocytic cycle (24 hr), will infect all ages of RBCs, and can cause serious disease B. Erythrocytic cycle limited to young RBCs and causes a relatively benign disease C. The possibility of a true relapse from the liver infection in older RBCs, and causes serious disease D. Extended cycle (72 hr), will infect all ages of RBCs, and disease is similar to that caused by P. ovale
Correct Answer: A
Kingella kingae can best be differentiated from Eikenella corrodens using which medium? A. Sheep blood agar B. Chocolate agar C. MacConkey agar D. XLD agar
Correct Answer: A
Large gram-positive bacilli (boxcar shaped) were recovered from a blood culture taken from a 70-year-old female diabetic patient. The following results were recorded: -Aerobic growth=Neg -Spores=Neg -Lecithinase=+ -Anaerobic growth=+ -Motility=Neg -Hemolysis=B (double zone) What is the most likely identification? A. Clostridium perfringens B. Fusobacterium spp. C. Bacteroides spp. D. Clostridium sporogenes
Correct Answer: A
MTM medium is used primarily for the selective recovery of which organism form genital specimens? A. Neisseria gonorrhoeae B. Neisseria lactamica C. Neisseria sicca D. Neisseria flavescens
Correct Answer: A
Micrococcus and Staphylococcus species are differentiated by which test(s)? A. Fermentation of glucose (OF tube) B. Catalase test C. Gram stain D. All of these options
Correct Answer: A
Microsporidial infections can be confirmed using: A. Light microscopy and modified trichrome stains B. Phase contrast microscopy and routine trichrome stains C. Electron microscopy and modified acid-fast stains D. Fluorescence microscopy and hematoxylin stains
Correct Answer: A
Mycobateria stained by the Ziehl-Neelsen or Kinyoun methods with methylene blue counterstain are seen microscopically as: A. Bright red rods against a blue background B. Bright yellow rods against a yellow background C. Orange-red rods against a black background D. Bright blue rods against a pink background
Correct Answer: A
Oocysts of Cryptosporidium spp. can be detected is stool specimens using: A. Modified Ziehl-Neelsen acid-fast stain B. Gram stain C. Methenamine silver stain D. Trichrome stain
Correct Answer: A
Organisms that should be considered in a waterborne outbreak of diarrheal disease include: A. Giardia lamblia and Crytosporidium spp. B. Endolimax nana and Entamoeba histolytica C. Blastocysitis hominis and Trichomonas vaginalis D. Toxoplasma gondii and Schistosoma mansoni
Correct Answer: A
Plasmodium vivax and Plasmodium ovale are similar because they: A. Exhibit Schuffner's dots and have a true relapse in the life cycle B. Have no malarial pigment and multiple rings C. Commonly have applique forms in the red cells D. Have true stippling, do not have a relapse stage, and infect old red cells
Correct Answer: A
Presumptive test used for identification of Pseudomonas spp. are: A. Oxidase, oxidation-fermentation (OF) glucose (open), OF glucose (sealed), motility, pigment production B. Growth on blood agar plate (BAP) and eosin-methylene (EMB) agars, lysine decarboxylation, catalase C. Growth on macConkey, EMB, and XLD agars, and motility D. Growth on mannitol slat agar and flagellar stain
Correct Answer: A
Resistance to which drug categorizes a strain of Staphylococcus aureus as methicillin-resistant Staphylococcus aureus (MRSA)? A. Oxacillin B. Colistin C. Trimethoprim-sulfamethoxazole D. Tetracycline
Correct Answer: A
S. pneumoniae and the viridans streptococci can be differentiated by which test? A. Optochin disk test, 5 ug/mL or less B. Bacitracin disk test, 0.04 unit C. CAMP test D. Bile esculin test
Correct Answer: A
SITUATION: After a vacation to the Southwestern United States, a midwesterner complained of flulike symptoms with fever, chills, nonproductive cough, and chest pain. Microscopic exam of sputum, cleared with KOH, revealed lard, thick-walled spherules containing endospores. Upon culture, the mold phase sowed septate hyphae and alternating barrel-shaped arthroconidia. Which organism is most likely the cause of this pneumonia? A. Coccidioides immitis B. Histoplasma capsulatum C. Paracoccidioides brasiliensis D. Penicillium marneffei
Correct Answer: A
SITUATION: Several attendees of a medical conference in the Gulf coast area became ill after frequenting a seafood restaurant. A presumptive identification of Vibrio cholera was made after stool specimens form several subjects grew clear colonies on macConkey agar and yellow colonies on TCBS agar. Which key tests would help eliminate Aeromonas and Plesiomonas spp.? A. Mannitol fermentation, Na+ requirement B. Oxidase, motility C. Oxidase, nitrate D. Hemolysis on blood agar, catalase
Correct Answer: A
Semisolid transport media such as Amies, Stuart, or Cary-Blair are suitable for the transport of swabs for culture of most pathogen except: A. Neisseria gonorrhoeae B. Enterobacteriaceae C. Camplyobacter fetus D. Streptococcus pneumoniae
Correct Answer: A
Spirochetes often detected in the hematology laboratory, even before the physician suspects the infections, are: A. Borrelia spp. B. Treponema spp. C. Campylobacter spp. D. Leptospira spp.
Correct Answer: A
Spores;Motility;Lecithinase;Double-Zone Hemol;GLC Prod C. tetani: Terminal*, Pos, Neg, Neg, A/B C. perfringnes: Subterminal, Neg, Pos, Pos, A/B C. novyi (B): Subterminal, Pos, Pos, Neg, A/C/P C. sporogenes: Subterminal, Pos, Neg, Neg, A/B *Usually lacking 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
Correct Answer: A
Sputum from a patient with pneumonia produced many colonies of gram-negative diplococci on a chocolate plate that were also present in fewer numbers on MTM after 48 hours. Given the following results, what is the most likely identification? -Catalase=+ -DNase=+ -Glucose=Neg -Lactose=Neg -Fructose=Neg -Oxidase=+ -Tributyrin hydrolysis=+ -Sucrose=Neg -Maltose=Neg A. Moraxella catarrhalis B. Neisseria flavescens C. Neisseria sicca D. Neisseria elongata
Correct Answer: A
Strains of Staphylococcus species resistant to the B-lactam antibiotics by standardized disk diffusion and broth microdilution susceptibility methods are called: A. Heteroresistant B. Bacteriophage group 52S C. Cross resistant D. Plasmid altered
Correct Answer: A
The B-galactosidase test aids in the identification of which Neisseria species? A. N. lactamica B. N. meningitidis C. N. gonorrhoeae D. N. flavescens
Correct Answer: A
The Hair Baiting Test is used to differentiate whic tow species of Trichophyton that produce red colonies on Sabouraud agar plates? A. T. mentagrophytes and T. rubrum B. T. tonsurans and T. schoenleinii C. T. tonsurans and T. violaceum D. T. verrucosum and T. rubrum
Correct Answer: A
A 15-year-old female complained of a severe eye irritation after removing her soft-contact lenses. A swab of the infected right eye was obtained by an ophthalmologist, who ordered a culture and sensitivity test. The culture was plated on blood agar and MacConkey agar. At 24 hours, growth of a gram0negative rod that tested positive for cytochrome oxidase was noted. The mueller-Hinton sensitivity plate showed a bluish-green "lawn" of growth that proved highly resistant to most of the antibiotics tested except amikacin, tobramycin, and ciprofloxacin. What is the most likely identification? A. Burkholderia cepacia B. Pseudomonas aeruginosa C. Stenotrophomas maltophilia D. Acinetobacter baumannii
Correct Answer: B
A 2-month-old infant in good health was scheduled for a checkup at the pediatrician's office. After arriving for the appointment, the mother noted white patches on the baby's tongue and in this mouth. The baby constantly used a pacifer. What is the most likely organism causing the white patches? A. Cryptococcus neoformans B. Candida albicans C. Aspergillus fumigatus D. None of these options
Correct Answer: B
A 25-year-ld pregnant patient complained of vaginal irritation. Cultures taken for STDs proved negative. A Gram-stained vaginal smear revealed many epithelia cells with gram-variable short rods (coccobacilli) covering the margins. What is the most likely cause of the vaginosis? A. Group B streptococci spp. B. Gardnerella vaginalis C. Staphylococcus aureus D. Staphylococcus saprophyticus
Correct Answer: B
A 30-year-old female patient complained of vaginal irritation and symptoms (fever, dysuria, and inguinal lymphadenopathy) associated with sexually transmitted disease (STD). Examination showed extensive lesions in the genital area. Chlamydia spp. testing, Neisseria gonorrhoeae, and Gardnerella vaginalis cultures were negative. Rapid plasma reagin (RPR) testing was also negative. What is the next line of testing? A. Darkfield examination B. Herpes simplex testing C. Trichomonas spp. testing D. Group B streptococcal testing
Correct Answer: B
A 5-year-old nonimmunized male with a persistent cough, fever, and flulike symptoms was admitted to the hospital. Nasopharyngeal swabs were cultured on 15% blood, chocolate, Bordet-Genjou, and Regan-Lowe (with 10% charcoal) agars. All media grew a gram-negative coccobacillus. Carbohydrate and biochemical tests were negative. What is the most likely identification? A. Haemophilus influenza B. Bordetalla pertusis C. Haemophilus parainfluenzae D. Bordetella bronchiseptica
Correct Answer: B
A CSF sample obtained from a 2-week old infant with suspected bacterial meningitis grew gram-negative rods on blood and chocolate agars. The following results were noted: -MacConkey agar=No growth -Glucose (open) OF=+ -Glucose (closed) OF=Neg -Indole=+ -Motility=Neg -42C growth=Neg -ONPG=+ -Urease=Neg -Catalase=+ -Oxidase=+ -Pigment=Yellow What is the correct identification? A. Pseudomonaas aeruginosa B. Chryseobacterium meningosepticum C. Acinetobacter baumannii D. E. coli
Correct Answer: B
A Vietnam War veteran presented with "glanders-like" infection (melioidosis). Several blood cultures produced gram-negative rods that were positive for cytochrome oxidase, oxidized glucose and xylose, and grew at 42C. What is the most likely organism? A. Stenotrophomonas maltophilia B. Burkholderia pseudomallei C. Pseudomonas aeruginosa D. Acinetobacter spp.
Correct Answer: B
A bone marrow specimen was obtained form an immunocompromised patient who tested positive for HIV. The organism grew rapidly at 3 days showing a mold form (at 25C), displaying conidiophores with four to five terminal metulae with each having four to six phialides. The conidia at the end of the phialides were oval and in short chains. They appear as a fan or broom when viewing under 10X and 40X. At 37C, the yeast form grew more slowly, showing conidia that formed hyphal elements breaking at the septa to produce oval arthroconidia. This thermodimorphic mold is most likely: A. Paecilomyces spp. B. Penicillium marneffei C. Rhizomucor spp. D. Aspergillus fumigatus
Correct Answer: B
A catalase-negative, gram-positive coccus resembling staphylococci (clusters on the Gram-stinaed smear) was recovered from three different blood cultures obtained form a 60-year-old patient diagnosed with endocarditis. The following test results were noted: -PYR=Neg -Esculin hydrolysis=Neg -Vancomycin=Sensitive -LAP=Neg (V) -6.5% Salt broth=Neg -CAMP test=Neg What is the correct identification? A. Leuconostoc spp. B. Genella spp. C. Enterococcus spp. D. Micrococcus spp.
Correct Answer: B
A curved gram-negative rod producing oxidase-positive colonies on blood agar was recovered form a stool culture. Given the following results, what is the most likely identification? -Lysine decarboxylase=+ -Indole=+ -VP=Neg -Urease=+/- -TCBS=Green colonies -Arginine decarboxylase=Neg -KIA=Alk/Acid -Lactose=Neg -String test=Neg A. Vibrio cholerae B. Vibrio parahaemolyticus C. Shigella spp. D. Salmonella spp.
Correct Answer: B
A dog bit wound to the thumb of a 20-year-old male patient became infected. The culture grew a gram-negative, slender rod, which was a facultative anaerobe. The following results were note: -Oxidase=+ -Catalase=+ -Motility=Neg -Capnophilic=+ "Gliding" on the agar was noted. What is the most likely identification? A. Pseudomonas aeruginosa B. Capnocytophaga canimorsus C. Acinetobacter baumannii D. Proteus mirabilis
Correct Answer: B
A germ tube-negative, pink yeast isolate was recovered form the respiratory secretions and urine of a patient with AIDS. Given the following results, what is the most likely identification? Cornmeal Tween 80 Agar -Blastoconidia=+ -Arthroconidia=Neg -Pseudohyphae=Neg -Urease=+ A. Candida albicans B. Rhodotorula spp. C. Crystococcus spp. D. Trichosporon spp.
Correct Answer: B
A gram-negative S-shaped rod recovered form selective media for Campylobacter species gave the following results: -Catalase=+ -Motility=+ -Growth at 42C=+ Grape odor=Neg -Oxidase=+ -Hippurate hydrolysis=+ -Nalidixic acid=Susceptible -Pigment=Neg -Cephalothin=Resistant The most likely identification is A. Pseudomonas aeruginosa B. Campylobacter jejuni C. Campylobacter fetus D. Pseudomonas putida
Correct Answer: B
A gram-negative nonfermenter was isolated from a culture taken from a burn patient. Which of the following is the best choice of test to differentiate Pseudomonas aeruginosa form Acinetobacter spp.? A. Growth on MacConkey agar, catalase, growth at 37C B. Oxidase, motility, growth at 42C C. Growth on blood agar, oxidase growth at 35C D. String test and coagulase test
Correct Answer: B
Examination of 24-hour unpreserved urine specimen is sometimes helpful in the recovery of: A. Trichomonas vaginalis B. Schistosoma haematobium eggs C. Enterobius vermincularis eggs D. Stronglyoides stercoralis larvae
Correct Answer: B
A leg-wound culture from a hospitalized 70-year-old diabetic man grew motile, lactose-negative colonies on MacConkey agar. Given the following biochemical reactions at 24 hours, what is the most probable organism? -H2S (TSI)=Neg -MR=Neg -DNase=+ -Urease=Neg -Phenylalanine deaminase=Neg -Ornithine and lysin decarboxylase=+ -Arginine decarboxylase=Neg -Gelatin hydrolysis=+ -Indole=Neg -VP=+ -Citrate=+ A. Proteus vulgaris B. Serratia marcescens C. Proteus mirabilis D. Enterobacter cloacae
Correct Answer: B
A listless 12-month-old boy with a fever of 103F was taken to the emergency department. He had been diagnosed with an ear infection 3 days earlier. A spinal tap was performed, but only one tube of CSF was obtained form the lumbar puncture. The single tube of CSF should be submitted first to which department? A. Chemistry B. Microbiology C. Hematology D. Cytology/Histology
Correct Answer: B
A lymph node biopsy obtained form a 30-year-old male patient was submitted to the microbiology laboratory for a culture and AFB smear for mycobacteria. The specimen was fixed in formalin. This specimen should be: A. Accepted for AFB smear and cultured B. Rejected C. Held at room temperature for 24 hours and then cultured D. Cultured for anaerobes only
Correct Answer: B
A neonate was readmitted to the hospital with a diagnosis of meningitis. The CSF revealed gram-negative straight rods. At 24 hours, the organism grew on 5% sheep blood and chocolate agars displaying a yellow pigment. On MacConkey agar, it appeared as a non-lactose fermenter. Colonies were oxidase, DNase, and gelatinase positive, and oxidized glucose and mannitol. what is the most likely identification? A. Haemophilus influenza B. Chryseobacterium meningosepticum C. Stenotrophomonas maltophilia D. Acinetobacter baumannii
Correct Answer: B
A nursing student working in the emergency department accidentally stuck herself with a needle after removing it from an intravenous set taken from a suspected drug user. The best course of action, after reporting the incident to her supervisor, is to: A. Test the student for HIV virus if flulike symptoms develop in 2-4 weeks B. Immediately test the patient and the student for HIV using an EIA or ELISA test C. Perform a Western blot assay on the student's serum D. Draw blood from the student only and freeze it for further testing
Correct Answer: B
A patient exhibits fever, chills, abdominal cramps, diarrhea, vomiting, and bloody stools 10 to 12 hours after eating. Which organisms will most likely grow form this patient's stool culture? A. Salmonella or Yersinia spp. B. E. coli 0157:H7 or Shigella spp. C. Staphylococcus aureus or Clostridium perfringens D. Salmonella or Staphylococcus
Correct Answer: B
A pediatric patient with severe bloody diarrhea who had been camping with his parents was admitted to the hospital with complications of hemolytic uremic syndrom (HUS). Several stool specimesn were cultured with the following results noted: -Gram stain smear= Many gram-negative rods with no WBCs seen -Blood agar=Normal flora -MacConkey agar=Normal flora -MacConkey agar with sorbitol=Many clear colonies (sorbitol negative) -Hektoen agar=Normal flora -Campy agar=No growth What is the most likely identification? A. Yersinia spp. B. E. coli 0157:H7 C. Salmonella spp. D. Shigella spp.
Correct Answer: B
A rapidly growing hyaline mold began as a white colony but soon developed a black "pepper" effect on the agar surface. the older colony produced a black matte, making it resemble a dematiaceous mold. What is the most likely identification? A. Penicillium notatum B. Aspergillus niger C. Paecilomyces spp. D. Scopulariopsis spp.
Correct Answer: B
A sheep blood agar plate is used as a primary isolation medium when all of the following organisms are to be recovered from a wound specimen except: A. Hemolytic streptococci and coagulase-positive staphylococci B. Haemophilus influenzae and Haemophilus parainfluenzae C. Proteus spp. and Escherichia coli D. Pseudomonas spp. and Acinetobacter spp.
Correct Answer: B
A small, gram-negative coccobacillus recovered from the CSF of a 2-year-old child gave the following results: -Indole=+ -X requirement=+ -Urease=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. Haemophilus aphrophilus
Correct Answer: B
A tissue biopsy specimens of the stomach was obtained from a 38-year-old male patient diagnosed with gastric ulcers. The specimen was transported immediately and precessed for culture and histology. At 5 days, the culture produced colonies of gram-negative (curved) bacilli on chocolate and Brucella agar with 5% sheep blood. The cultures were held at 35C-37C in a microaerophilic atmosphere. The colonies tested positive for urease. The most likely identification is: A. E. coli B. Helicobacter pylori C. Enterococcus faecalis D. Streptococcus bovis
Correct Answer: B
A transplant patient on immunosuppressive drugs developed increasings diarrhea. The most likely combination of disease and diagnostic procedure is: A. Trichinosis and trichrome stain B. Microsporidiosis and modified trichrome stain C. Toxoplasmosis and Gram stain D. Paragonimiasis and wet preparation
Correct Answer: B
A wound (skin lesion) specimen obtained from a newborn grew predominantly B-hemolytic colonies of gram-positive cocci on 5% sheep blood agar. The newborn infant was covered with small skin eruptions that gave the appearance of a "scalding of the skin." The gram-positive cocci proved to be catalase positive. Which tests should follow for the appropriate identification? A. Optochin, bile solubility, PYR B. Coagulase, glucose fermentation, DNase C. Bacitracin, PYR, 6.5% salt broth D. CAMP, bile-esculin, 6.5% salt broth
Correct Answer: B
A young father of two small children complained of a rash on the torso of his body. The children had been diagnosed with chickenpox and confined to their home. The father had experience chickenpox as a child and knew he did not have the same rash as his children. What is the most likely cause of the father's rash? A. Herpes simplex 1 virus B. Varicella-zoster virus C. Herpes simplex 2 virus D. Epstein-Barr virus
Correct Answer: B
A young male hunter encountered a fox in his path during a walk in the woods. The fox was staggering but appeared nonthreatening. The man tried to avoid contact but was attached and bitten on the leg. The bit broke the skin but was not deep. Wildlife official were unable to locate the fox for testing. What procedure should take place next for the hunter? A. Spinal tap with CSF B. Administration of hyperimmune antirabies globulin and rabies vaccine C. Biopsy of the wound site D. Throat culture and blood culture
Correct Answer: B
According to the College of American Pathologists (CAP) guidelines, which services for mycobacteria would be performed by a Level II laboratory? A. No procedures performed B. Acid-fast staining, inoculation, and referral to a reference laboratory C. Isolation and identification of Mycobacterium tuberculosis; preliminary identification of other species D. Definitive identification of all mycobacteria
Correct Answer: B
All of the following Mycobacterium spp. produce the enzyme required to convert niacin to niacin ribonucleotide except: A. M. kansaii B. M. tuberculosis C. M. avium-intracellulare complex D. M. szulgai
Correct Answer: B
Although a patient is strongly suspected of having giardiasis and is still symptomatic, three routine stool examination (O&P exam) have been performed correctly and reported as negative. Biopsy confirmed the patient had giardiasis. Reasons for this findings may include: A. The patient was coinfected with several bacterial species B. Giardia lamblia tends to adhere to the mucosal surface and more than three stool examination may be required fo confirm a suspected infection C. The organisms persent did not stain with trichrome stain and therefore the morphology is very atypical D. Special diagnostic procedures such as the Knott concentration and nutrient-free agar cultures should have been used
Correct Answer: B
Although the pathogenicity of Blastocystis hominis remains controversial, newer information suggest that: A. MOst organism are misdiagnosed as artifacts B. Numerous strains/species are included in the name, some of which are pathogenic and some are nonpathogenic C. The immune status of the host is solely responsible for symptomatic infections D. The number of organisms present determines pathogenicity
Correct Answer: B
An India ink test was performed on CSF from an HIV-infected male patient. Many encapsulated yeast cells were seen in the centrifuged sample. Further testing revealed a positive urease test and growth of brown colonies on niger-seed agar. The diagnosis of meningitis was caused by which yeast? A. Candida albicans B. Cryptococcus neoformans C. Cryptococcus laurentii D. Candida tropicalis
Correct Answer: B
An immunocompromised 58-year-old female chemotherapy patient received 2 units of packed RBCs. The patient died 3 days later, and the report from the autopsy revealed that her death was due to septic shock. The blood bags were cultured, and the following results were noted: -GROWTH OF AEROBIC GRAM-NEGATIVE RODS ON BOTH MACCONKEY AND BLOOD AGARS -Lactose=Neg -Indole=Neg -Urease=+ -Sucrose=+ -VP=Neg -Motility 22C=+ -Citrate=Neg -H2S=Neg -Motility 37C=Neg What is the most likely identification? A. Escherichia coli B. Yersinia entercolitica C. Enterobacter cloacae D. Citrobacter freundii
Correct Answer: B
An immunosuppressed man has several episodes of pneumonia, intestinal pain, sepsis with gram-negative rods, and a history of military service in Southeast Asia 20 years earlier. The most likely cause is infection with: A. Trypanosoma cruzi B. Strongyloides stercoralis C. Naegleria fowleri D. Paragonimus westermani
Correct Answer: B
An isolate recovered form a vaginal culture obtained form a 25-year-old female patient who is 8 months pregnant is who to be a gram-positive cocci, catalase negative, and B-hemolytic on blood agar. Which tests are needed for further identification? A. Optochin, bile solubility, PYR B. Bacitracin, CAMP, PYR C. Methicillin, PYR, trehalose D. Coagulase, glucose, PYR
Correct Answer: B
An operculated cestode egg that can be recovered form human feces is: A. Clonorchis sinensis B. Diphyloobothrium latum C. Paragonimus westermani D. Dipylidium caninum
Correct Answer: B
Anaerobic gram-negative bacilli were recovered from fluid obtained from drainage of a postsurgical abdominal wound. The following test results were recorded: -Kanamycin=Resistant -Colistin=Resistant -Vancomycin=Resistant -Growth on 20% bile plate=+ -Pigment=Neg -Indole=V (Neg) -Nitrate=Neg -Urease=Neg -Lipase=Neg What is the correct identification? A. Prevotella spp. B. Bacteroides fragilis group C. Porphyromonas spp. D. Clostridium spp.
Correct Answer: B
Anaerobic gram-negative rods were recovered form the blood of a patient after gallbladder surgery. The bacteria grew well on agar containing 20% bile, but were resistant to kanamycin and vancomycin. What is the most likely identification? A. Clostridium perfringens B. Bacteroides fragilis group C. Prevotella spp. D. Porphyromonas spp.
Correct Answer: B
Anaerobic gram-positive diphtheroids (nonspore formers) were culture from two separate blood bulture bottles (at 5 days) obtained from a 25-year-old patient admitted to the hospital with dehydration, diarrhea, and other flulike symptoms. Four other blood culture bottles did not grow any organisms at 7 days and were discarded. The following results were obtained from the recovered anaerobe: -Indole=+ -Kanamycin=Sensitive -Colistin=Resistant -Nitrate=+ -Catalase=+ -Vancomycin=Sensitive -Major acid from PYG broth by GLC= Propionic acid What is the correct identification? A. Eubacterium lentum B. Propionibacterium acnes C. Actinomyces spp. D. Peptostreptcoccus spp.
Correct Answer: B
Arthroconidia production is used to differentiate which two yeast isolates? A. Candida albicans and Candida dubliniensis B. Trichosporon cutaneum and Crytococcus neoformans C. Candida albicans and Candida tropicalis D. Saccharomyces cerevisiae and Candida glabrata
Correct Answer: B
Cetrimide agar is used as a selective isolation agar for which organism? A. Acinetobacter spp. B. Pseudomonas aeruginosa C. Moraxella spp. D. Strenotrophomonas maltophilia
Correct Answer: B
Charcot-Leyden crystals in stool may be associated with an immune response and are thought to be formed from the breakdown products of: A. Neutrophils B. Eosinophils C. Monocytes D. Lymphocytes
Correct Answer: B
Chocolate agar and modified Thayer-Martin agar are used for the recovery of: A. Haemophilus spp. and Neisseria spp., respectively B. Haemophilus spp. and N. gonorrhoeae, respectively C. Neisseria spp. and Streptococcus spp., respectively D. Streptococcus spp. and Staphylococcus spp., respectively
Correct Answer: B
Cutaneous disease involving skin, hair, and nails usually indicates an infection with a: A. Dimorphic fungus B. Dermatophyte C. Zygomycetes D. Candida species
Correct Answer: B
Dimorphic mold are found in infected tissue in which form? A. Mold phase B. Yeast phase C. Encapsulated D. Latent
Correct Answer: B
SITUATION: A patient tested positive for HIV-1 infection using a reverse transcriptase-polymerase chain reaction (RT-PCR) method. however, 1 week later a second blood sample was collected and sent to a reference lab that performed a confirmatory test by Western blot. The Western blot test was negative. What best explains these results? A. The samples for RT-PCR and Western blot were not form the same patient B. RT-PCR is more sensitive for early detection C. The RT-PCR result was falsely positive D. The RT-PCR test detected HIV-2 and the Western blot is specific for HIV-1
Correct Answer: B
SITUATION: A pregnant women was seen by her obstetrician with signs of flulike illness during her second trimester. NAT test were ordered for Toxoplasma gondii, rubella, cytomegalovirus, and herpes simplex 1 and 2. All test results were negative. However, after delivery, the newborn exhibited signs of an infection and failed to survive. Which virus causes a 90% transplacental infection rate when found in the mother? A. Hepatitis A B. Hepatitis B C. Hepatitis D D. Hepatitis G
Correct Answer: B
Select the media of choice for recovery of Vibrio cholerae form a stool specimen. A. MacConkey agar and thioglycollate media B. Thiosulfate-citrate-bile sucrose (TCBS_ agar and alkaline peptone water (APW broth) C. Blood agar and selenite-F (SEL) broth D. CNA agar
Correct Answer: B
Select the medium best suited for the recovery of Yersinia entercolitica from a patient with gastroenteritis. A. Hektoen agar B. Cefsulodin-Irgasan-Novoviocin (CIN) agar C. Blood agar D. Eosinmethylene blue agar
Correct Answer: B
Smooth gray colonies showing no hemolysis are recovered from an infected cat scratch on blood and chocolate agar but fail to grow on MacConkey agar. The organisms are gram-negative pleomorphic rods that are both catalase and oxidase positive and strongly indole positive. The most likely organism is: A. Capnocytophaga spp. B. Pasteurella spp. C. Proteus spp. D. Pseudomonas spp.
Correct Answer: B
Staphylococcus saprophyticus is best differentiated form Staphylococcus epidermidis by resistance to: A. 5 ug of lysostaphin B. 5 ug of novobiocin C. 10 units of penicillin D. 0.04 unit bacitracin
Correct Answer: B
Streptococcus species exhibit which of the following properties? A. Aerobic, oxidase positive, and catalase positive B. Facultative anaerobe, oxidase negative, catalase negative C. Facultative anaerobe, B-hemolytic, catalase positive D. May be a-, B-, or y-hemolytic, catalase positive
Correct Answer: B
The HACEK group of organisms (Haemophilus apharophilus, actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella spp.) are all known for which type of infections? A. Urinary tract B. Endocarditis C. Pharyngitis D. Tonsillitis
Correct Answer: B
The India ink stain is used as a presumptive test for the presence of which organism? A. Aspergillus niger in blood B. Cryptococcus neoformans in CSF C. Histoplasma capsulatum in CSF D. Candida albicans in blood or body fluids
Correct Answer: B
The Shiga-like toxin (verotoxin) is produced mainly by which Enterobacteriaceae? A. Klebsiella pneumoniae B. E. coli C. Salmonella typhimurium D. Enterobacter cloacae
Correct Answer: B
The aseptic collection of blood cultures requires that the skin be cleansed with: A. 2% iodin and then 70% alcohol solution B. 70% alcohol and then 2% iodine or an iodophor C. 70% alcohol and then 95% alcohol D. 95% alcohol only
Correct Answer: B
The bile solubility test causes the lysis of: A. Streptococcus bovis colonies on a blood agar plat B. Streptococcus pneumoniae colonies on a blood agar plate C. Group A streptococci in broth culture D. Group B streptococci in broth culture
Correct Answer: B
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
Correct Answer: B
The following characteristics of an obligate anaerobic gram-negative bacilli best describe which o 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.
Correct Answer: B
The formalin-ether (ethyl acetate) concentration procedure for feces is used to demonstrate: A. Motility of helminth larvae B. Protozoan cysts and helminth eggs C. Formation of amoebic pseudopods D. Trophozoites
Correct Answer: B
The incorrect match between method and method objective is: A. Direct wet examination- detection of organism motility B. Knott's concentration- the recovery of operculated helminth eggs C. Baermann's concentration- the recovery of Strongyloides D. Permanent stained fecal smear- confirmation of protozoa
Correct Answer: B
The majority of clinical laboratories with a microbiology department should have the capability o serotyping which pathogenic Enterobacteriaceae? A. Yersinia enterocolitica, Shigella spp. B. E. coli 0157:H7, Salmonella spp., Shigella spp. C. Yersinia pestis, Salmonella spp. D. Edwardsiella spp., Salmonella spp.
Correct Answer: B
The manganous chloride-urea test is used for the identification of which organism? A. Mycoplasma pneumoniae B. Ureaplasma urealyticum C. Bacillus cereus D. Borrelia burgdorferi
Correct Answer: B
The miracidial hatching test helps to demonstrate the viability of eggs of: A. Taenia species B. Schistosoma species C. Hookworm species D. Opisthorchis species
Correct Answer: B
The organs of a 65-year-old male were donated soon after a fatal auto accident. Three recipients of his corneas and kidneys died with weeks after receiving his organs. Which of the following viruses most likely caused the death of these recipients? A. HIV B. Rabies C. Norwalk-like D. Rotavirus
Correct Answer: B
The ortho-nitrophenyl-B-galactopyranoside (ONPG) test is most useful when differentiating: A. Salmonella spp. from Psudomonas spp. B. Shigella spp. from some stains of Escherichia coli C. Klebsiella spp. from Enterobacter spp. D. Proteus vulgaris from Salmonella spp.
Correct Answer: B
The test used most often to separate the Micrococcaceae family from the Streptococcaceae family is: A. Bacitracin B. Catalase C. Hemolysis pattern D. All of these options
Correct Answer: B
Two blood cultures on a newborn grew B-hemolytic streptococci with the following reactions: -CAMP test=+ -Bile solubility=Neg -Bacitracin=Resistant -PYR=Neg -Trimethoprim-sulfamethoxazole: Resistant -Hippurate hydrolysis=+ -6.5% salt=+ -Bile esculin=Neg Which is the most likely identification? A. Group A streptococci B. Group B streptococci C. Group D streptococci D. Nongroup A, nongroup B, nongroup D streptococci
Correct Answer: B
What concentration of sodium hydroxide (NaOH) is used to prepare a working decontamination solution of the processing of not normally sterile specimens for mycobacteria? A. 1% NaOH B. 4% NaOH C. 8% NaOH D. 12% NaOH
Correct Answer: B
When staining Cystoisospora belli oocysts with modified acid-fast stains, the important difference between these methods and the acid-fast stains used for acid-fast bacilli (AFB) is: A. The staining time is much longer with regular AFB acid-fast stains B. The decolorizer is weaker than acid alcohol used for AFB acid-fast stains C. A counterstain must be used for the modified methods D. The stain is more concentrated when staining for AFB
Correct Answer: B
Which Clostridium spp. causes pseudomembranous colitis or antibiotic-associated colitis? A. C. ramosum B. C. difficile C. C. perfringens D. C. sprogenes
Correct Answer: B
Which Haemophilus species is difficult to isolate and recover from genital ulcers and swollen lymph nodes? A. H. aphrophilus B. H. ducreyi C. H. haemolyticus D. H. parahaemolyticus
Correct Answer: B
Which Mircosporum species causes an epidemic form of tinea capitis in children? A. Microsporum canis B. Microsporum audouinii C. Microsporum gypseum D. All of these options
Correct Answer: B
Which Pseudomonas is usually associated with a lung infection related to cystic fibrosis? A. P. fluorescens B. P. aeruginosa C. P. putida D. Burkholderia pseudomallei
Correct Answer: B
Which are the best two tests to differentiate A. hydrophilia from P. shigelloides? A. Oxidase and motility B. DNase and VP C. Indole and lysine decarboxylase D. Growth on MacConkey and blood agar
Correct Answer: B
Which genera are positive for phenylalanime deaminase? A. Enterobacter, Escherichia, and Salmonella B. Morganella, Providencia, and Proteus C. Klebsiella and Enterobacter D. Proteus, Escherichia, and Shigella
Correct Answer: B
Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric pathogens? A. Enterobacter, Klebsiella, Providencia, and Proteus B. Escherichia, Salmonella, Shigella, and Yersinia C. Pseudomonas, Moraxella, Acinetobacter, and Aeromonas D. Enterobacter, Citrobacter, Morganella
Correct Answer: B
Which group of molds can be ruled out when septate hyphae are observed in a culture? A. Dematiaceous B. Zygomycetes C. Dermatophytes D. Dimorphic molds
Correct Answer: B
Which group of test best differentiates Enterobacter aerogenes form Edwardsiella tarda? A. Motility, citrate, and urease B. Hydrogen sulfide (H2S) production, sucrose fermentation, indole, and VP C. Lysine decarboxylase, urease, arginine D. Motility, H2S production, and DNase
Correct Answer: B
Which is the test of choice for the confirmation of Chlamydia trachomatis infection in urine? A. Enzyme immunoassay antigen testing B. PCR molecular testing C. Culture using McCoy and Hela cells D. Microimmunofluorescence (MIF) test
Correct Answer: B
Which mycobacterium is associated with Crohn's disease? A. M. marinum B. M. paratuberculosis C. M. avium D. M. gordonae
Correct Answer: B
Which mycobacterium of the M. tuberculosis complex fails to grow in culture and has a characteristic "croissant-like" morphology in stained smears? A. M. africanum B. M. microti C. M. bovis D. M. leprae
Correct Answer: B
Which of the following enzymes contribute to the virulence of S. aureus? A. Urease and lecithinase B. Hyaluronidase and B-lactamase C. Lecithinase and catalase D. Cytochrome oxidase
Correct Answer: B
Which of the following is the best technique to identify Dientamoeba fragilis in stool? A. Formalin concentrate B. Trichrome-stained smear C. Modified acid-fast-satined smear D. Giemsa's stain
Correct Answer: B
Which of the following organisms is often confused with the Salmonella species biochemically and on plated media? A. E. coli B. Citrobacter freudii C. Enterobacter cloacae D. Shigella dysenteriae
Correct Answer: B
Which of the following organisms, found in normal fecal flora, may be mistaken biochemically for the genus Yersinia? A. Klebsiella spp. B. Proteus spp. C. E. coli D. Enterobacter spp
Correct Answer: B
Which of the following plates should be used in order to identify Haemophilus haemolyticus and haemophilus parahaemolyticus? A. Chocolate agar an Mueller-Hinton agar with X factor added B. Horse blood agar and Mueller-Hinton agar with X and V strips C. Brain-heart infusion agar with sheep red cells added D. Chocolate agar and Mueller-Hinton agar with X factor added
Correct Answer: B
Which of the following test best differentiates Shigella species form E. coli? A. Hydrogen sulfide, VP, citrate, and urease B. Lactose, indole, ONPG, and motility C. Hydrogen sulfide, MR, citrate, and urease D. Gas, citrate, and VP
Correct Answer: B
Which of the following tests may be used to differentiate Cardiobacterium hominis from Actinobacillus spp.? A. Gram Stain B. Indole C. Anaerobic incubation D. Oxidase
Correct Answer: B
Which parasite causes eosinophilic meningoencephalitis, a form of larva migrans causing fever, headache, stiff neck, and increase cells in the spinal fluid? A. Necator americanus B. Angiostrongylus cantonensis C. Ancylostoma braziliense D. Strongyloides stercoralis
Correct Answer: B
Which temperature range is ideal for the recovery of M. marinum? A. 24C-26C B. 30C-32C C. 42C-44C D. 44C-48C
Correct Answer: B
Which test is used for the determination of inducible clindamycin resistance in staphylococci and streptococci? A. E-test B. D-zone test C. A-test D. Camp test
Correct Answer: B
A 13-year-old was admitted to the hospital with a diagnosis of viral encephalitis. History revealed that the boy harbored wild raccoons form nearby woods. What is the best method to determine if the boy has contracted rabies? A. Remover the brainstems from all of the racccons and examine for cytopathic effects B. Request immunofluorescent test for antibody on the saliva fro mall of the raccoons C. Request immunofluorescent test for antigen in cutaneous nerves obtained by nuchal biopsy of the patient D. Isolate the virus form the saliva of both the animals and the patient
Correct Answer: C
A 20-year-old female college student complained of a sore throat and extreme fatigue. The physician noted lymphadenophathy and ordered a rapid test for infectious mononulceosis antibodies that was negative. Bacterial cultures were negative, as were serological tests for influenza A and B, HIV-1, CMV, hepatitis B, antistreptolysin O. What would be the next line of viral testing to establish a diagnosis? A. Herpes simplex B. Rubella C. Epstein-Barr D. West Nile
Correct Answer: C
A 6-year-old female patient was admitted to the hospital following 2 days of severe diarrhea. Cultures from three consecutive stool samples contained blood and mucus. Patient history revealed a hamburger lunch at a fast-food restaurant 3 days earlier. Which pathogen is most likely responsible for the following results? Growth on: -XLD agar=yellow colonies -HE agar=yellow colonies -Mac agar=light pink and dark pink colonies -Mac with sorbitol agar-few dark pink and many colorless colonies A. Salmonella spp. B. Shigella spp. C. E. coli 0157:H7 D. Yersinia enterocolitica
Correct Answer: C
A 79-year-old female nursing home patient was admitted to the hospital with a fever and central nervous system dysfunction. Routine blood work and blood cultures were ordered. After 48 hours, the blood cultures revealed a budding yeast. The followign test performed form Sabourand dextrose agar (after 3 days of growth) showed: -Germ tube:Neg growth -Urease=+ -Blastospores=+ -Assimilation agar=+ (dextrose, sucrose, maltose) -Birdseed agar=Brown -Pseudohypae=Neg -Chlamydospores=Neg What is the most likely identification? A. Candida albicans B. Cryptococcus laurentii C. Cryptococcus neoformans D. Candida tropicalis
Correct Answer: C
A Mycobacteriuum species recovered from a patient with AIDS gave the following results: -Niacin=Neg -Tween 80 hydrolysis=Neg -T2H=+ -Nitrate reduction=Neg -Heat-stable catalase (68C)=+/- -Nonphotochromogen What is the most likely identification? A. M. gordonae B. M. bovis C. M. avium-intracellulare complex D. M. kansasii
Correct Answer: C
A flexible calcium alginate nasopharyngeal swab in the collection device of choice for recovery of which organism from the nasopharynx? A. Staphylococcus aureus B. Streptococcus pneumoniae C. Corynebacterium diphtheriae D. Bacteroides fragilis
Correct Answer: C
A gram-positive coccus recovered form a wound ulcer form a 31-year-old diabetic patient showed pale yellow, creamy, B-hemolytic colonies on blood agar. Given the following test results, what is the most likely identification? -Catalase=+ -Glucose OF: positive open tube, negative sealed tube -Mannitol salt=Neg -Slide coagulase=Neg A. Staphylococcus aureus B. Staphylococcus epidermidis C. Micrococcus spp. D. Streptococcus spp.
Correct Answer: C
A gram-positive spore-forming bacillus growing on sheep-blood agar anaerobically produces a double zone of B-hemolysis and is positive for lecithinase. What is the presumptive identification? A. Bacteroides ureolyticus B. Bacteroides fragilis C. Clostridium perfringens D. Clostridium difficile
Correct Answer: C
A specimen from a 15-year old female burn patine was cultured after debridement, and the following results were obtained: -Oxidase=+ -Catalase=+ -Ornithine decarboxylase=Neg -Arginine dihydrolase=+ -Penicillin=Resistant -Colistin (Polymixin B)= Susceptible -Lysine decarboxylase=Neg -Motility=+ -Glucose=+ for oxidation (open tube) -Maltose=Neg for oxidation (open tube) -Aminoglycosides=Susceptible These results indicate which of the following organism? A. Acinetobacter baumannii B. Moraxella lacunata C. Pseudomonas aeruginosa D. Acinetobacter lwoffi
Correct Answer: C
A sputum specimen from an 89-year-old male patient with suspected bacterial pneumonia grew a predominance of gram-positive cocci displaying alpha-hemolysis on 5% sheep blood agar. The colonies appeared donut shaped and mucoidy and tested negative for catalase. The most appropriate test for a final identification are: A. Coagulase, glucose fermentation. lysostaphin B. Penicillin, bacitracin, CAMP C. Optochin, bile solubility, PYR D. Bile esculin, hippurate hydrolysis
Correct Answer: C
A transplant patient is currently receiving steroids. The patient is now complaining of abdominal pain and has symptoms of pneumonia and positive blood cultures with gram-negative rods. The individual has been living in the United States for 20 years but grew up in Central America. The most likely parasite causing these symptoms is: A. Trypanosome brucei rhodesiense B. Giardia lamblia C. Strongyloides stercoralis D. Schistosoma japonicum
Correct Answer: C
A transplant patient is suspected of having invasive aspergillosis on the basis of clinical and radiological findings. Which specimen is best for the initial identification of aspergillosis by soluble antigen testing? A. Blood culture B. Lung biopsy C. Serum or urine D. Sputum
Correct Answer: C
A visitor to South America who returned with diarrhea is supected of being infected with V. cholerae. Select the best medium for recovery and identification of this organism. A. MacConkey agar B. Blood agar C. TCBS agar D. XLD agar
Correct Answer: C
A. Haemophilus spp., recovered from a throat culture obtained from a 59-year-old male patient undergoing chemotherapy, required hemin (X factor) and NAD (V factor) for growth. This species also hemolyzed horse erythrocytes on blood agar. What is the most likely species? A. H. ducreyi B. H. parahaemolyticus C. H. haemolyticus D. H. aegytius
Correct Answer: C
An emergency department physician suspected Corynebacterium diphtheriae when examining the sore throat of an exchange student from South America. What is the appropriate media for the culture of the nasopharyngeal swab obtained from the patient? A. Chocolate agar B. Thayer-Martin agar C. Tinsdale medium D. MacConkey agar
Correct Answer: C
An isolate of Staphylococcus aureus was cultured form an ulcer obtained form the leg of a diabetic 79-year-old female patient. The organism showed resistance to methicillin. Additional, this isolate should be tested for resistance or susceptibility to : A. Erythromycin B. Gentamicin C. Vancomycin D. Kanamycin
Correct Answer: C
B-hemolytic streptococci, more than 50,000 col/mL, were isolated from a urinary tract catheter urine specimen. Given the following reactions, what is the most likely identification? -CAMP test=Neg -Bile solubility=Neg -PYR=+ -SXT=Resistant -Optochin=Resistant -Hippurate hydrolysis=+/- -6.5% salt=+ -Bile esculin=+ -Bacitracin= Resistant A. Group A streptococci B. Group B streptococci C. Enterococcus faecalis D. Nongroup A, nongroup B, nongroup D streptococci
Correct Answer: C
Chlamydospore production is demonstrated by which Candida species? A. C. glabrata B. C. krusei C. C. albicans D. C. tropicalis
Correct Answer: C
Classification of viruses is made by: A. Complement fixation serology B. Electron microscopy C. Nucleic acid composition D. Cellular inclusion bodies
Correct Answer: C
Confirmation of an infection with microsporidia can be achieved by seeing: A. The oocyst wall B. Sporozoites within the spore C. Evidence of the polar tubule D. Organisms stained with modified acid-fast stains
Correct Answer: C
Culture of a finger wound specimen from a meat packer produced short gram-positive bacilli on a blood agar plate with no hemolysis. Given the following test results at 48 hours, what is the most likely identification? -Catalase=Neg -Motility(wet prep)=Neg -Motility (media)=Neg (bottle-brush growth in stab culture) A. Bacillus cereus B. Listeria monocytogenes C. Erysipelothrix rhusiopathiae D. Bacillus subtilis
Correct Answer: C
Cultures obtained form a dog bite wound produced yellow, tan, and slightly pink colonies on blood and chocolate agar with a margin of fingerlike projection appearing as a film around the colonies. Given the following results at 24 hours, which is the most likely organism? -Oxidase=+ -Growth on MacConkey agar=Neg -Catalase=+ -Motility=Neg A. Actinobacillus spp. B. Eikenella spp. C. Capnocytophaga spp. D. Pseudomonas spp.
Correct Answer: C
Cystine tryptic digest (CTA) media used for identification of Neisseria spp. should be inoculated and cultured in: A. A CO2 incubator at 35C for 24 hours B. A CO2 incubator at 42C for up to 72 hours C. A nonCO2 incubator at 35C for up to 72 hours D. An anaerobic incubator at 35C for up to 72 hours
Correct Answer: C
Cysts of Iodamoeba butschlii typically have: A. Chromatoidal bars with rounded ends B. A heavily vacuolated cytoplasm C. A large glycogen vacuole D. Many ingested bacteria and yeast cells
Correct Answer: C
Early ring stages of the fifth human malaria, Plasmodium knowlesi, resemble those of: A. Plasmodium malariae B. Plasmodium ovale C. Plasmodium falciparum D. Plasmodium vivax
Correct Answer: C
Examination of a modified acid-fast stained fecal smear reveals round structures measuring approximately 8-10 um, some of which are stained and some of which are not. They do not appear to show any internal morphology. The patient is symptomatic with diarrhea, and the cause may be: A. Blastocystis hominis B. Polymorphonuclear leukocytes C. Cyclospora cayetanensis D. Large yeast cells
Correct Answer: C
Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the: A. Ration of lactose to glucose B. Ability to detect H2S production C. Use of sucrose in the medium D. Color reaction denoting production of acid
Correct Answer: C
Microscopic examination of a fungus cultured from a patient with athlete's foot showed large, smooth-walled, club-shaped macroconidia appearing singly or in clusters of two to three from the tips of short conidiophores. The colonies did not produce microconidia. What is the most likely identification? A. Trichophyton spp. B. Alternaria spp. C. Epidermophyton spp. D. Microsporum spp.
Correct Answer: C
One of the following protozoan organisms has been implicated in water borne and foodborne outbreaks within the United States. The suspect organism is: A. Pentatrichomonas hominis B. Dientamoeba fragilis C. Giardia lamblia D. Balantidium coli
Correct Answer: C
Organism (and infections) that under normal conditions cannot be transmitted in the laboratory are: A. Cryptosporidium-crytosporidiosis B. Taenia solium- cysticercosis C. Ascaris lumbricoides- ascariasis D. Enterobius vermicularis- pinworm infections
Correct Answer: C
Parasitic organisms that are most often transmitted sexually include: A. Entamoeba gingivalis B. Dientamoeba fragilis C. Trichomonas vaginalis D. Diphyllobothrium latum
Correct Answer: C
Patients with severe diarrhea should use "enteric precautions" to prevent nosocomial infections with: A. Giardia lamblia B. Ascaris lumbricoides C. Cryptosporidium spp. D. Cystoisospora belli
Correct Answer: C
Primary infections with the microsporidia may originate in: A. The lung B. The nervous system C. The gastorintestinal tract D. Mucocutaneous lesions
Correct Answer: C
Protozoan cysts were seen in a concentration sediment and tentatively identified as Entamoeba coli. However, the organisms were barely visible on the permanent stained smear because: A. The organisms were actually not present in the concentrate sediment B. There were too few cysts to allow identification on the stained smear C. E. coli cysts were present but poorly fixed D. The concentrate and permanent stained smear were not from the same patient
Correct Answer: C
Putrescine is an alkaline amine product of which bacterial enzyme? A. Arginine decarboxylase B. Phenylalanime deaminase C. Ornithine decarboxylase D. Lysin decarboxylase
Correct Answer: C
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. XLD agar B. MacConkey agar C. MacConkey agar with sorbitol D. Hektoen agar
Correct Answer: C
Select the method of choice for recovery of anaerobic bacteria from a deep abscess. A. Cotton fiver swab or the abscess area B. Skin snip of the surface tissue C. Needle aspirate after surface decontamination D. Swab of the scalpel used for debridement
Correct Answer: C
Select the most sensitive recovery method for Acanthamoeba spp. from lens care solutions or corneal biopsies. A. The trichrome staining method B. The use of monoclonal reagents for the detection of antibody C. The use of non-nutrient agar cultures seeded with Wscherichia coli D. The Giemsa's stain method
Correct Answer: C
Three consecutive stool cultures form a 25-year-old male patient produced scant normal fecal flora on MacConkey and Hektoen agars. However, colonies on CIN agar (cefsulodin-irgasan-novobiocin) displayed "bulls-eye" colonies after 48 hours incubation. The patient had been suffering from enterocolitis with fever, diarrhea, and abdominal pain for 2 days. What is the most likely identification of this gram-negative rod? A. E. coli B. Proteus mirabilis C. Yersinia enterocolitica D. Klebsiella pneumoniae
Correct Answer: C
Toxic shock syndrome is attributed to infection with: A. Staphylocoocus epidermidis B. Staphylococcus hominis C. Staphylococcus aureus D. Staphylococcus saprophyticus
Correct Answer: C
Upon examination of stool material for Cytoisospora belli, one would expect to see: A. Cysts containing sporozoites B. Precysts containing chromatoidal bars C. Oocysts that are modified acid-fast variable D. Sporozoites that are hematoxylin positive
Correct Answer: C
What are the most appropriate screening test to presumptively differentiate and identify the nonfermentative gram-negative bacilli (NFB) from the Enterbacteriaceae? A. Catalase, decarboxylation of arginine, growth on blood agar B. Motility, urease, morphology on blood agar C. Oxidase, TSI, nitrate reduction, growth on MacConkey agar D. Oxidase, indole, and growth on blood agar
Correct Answer: C
When cleansing the skin with alcohol and then iodine for the collection of a blood culture, the iodine (or iodophor) should remain intact on the skin for at least: A. 10 sec B. 30 sec C. 60 sec D. 5 min
Correct Answer: C
When malaria smears are requested, what patient information should be obtained? A. Diet, aga, sex B. Age, antimalarial medication, sex C. Travel history, antimalaria medication, date of return to United States D. Fever patterns, travel history, diet
Correct Answer: C
Which Aspergillus species, recovered from sputum or bronchial mucus, is the most common cause of pulmonary aspergillosis? A. A. niger B. A. flavus C. A. funigatus D. All of these options
Correct Answer: C
Which Haemophilus species is generally associated with endocarditis? A. H. influenzae B. H. ducreyi C. H. aphrophilus D. H. haemolyticus
Correct Answer: C
Which agar that is used for routine stool cultures is the medium of choice for the isolation of Yersinia strains form stool specimens? A. Salmonella-Shigella agar B. Hektoen enteric agar C. MacConkey agar D. CNA agar
Correct Answer: C
Which is the most appropriate nonselective medium for recovery of mycobacteria from a heavily contaminated specimen? A. Lowenstein-Jensen agar B. Middlebrook 7H10 agar C. Petragnani's agar D. American Thoracic Society medium
Correct Answer: C
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
Correct Answer: C
Which of the following statements is true regarding onchocerciasis? A. The adult worm is present in the blood B. The microfilariae are in the blood during the late evening hours C. The diagnostic test of choice is the skin snip D. The parasite resides in the deep lymphatics
Correct Answer: C
Which of the following tests will rapidly differentiate micrococci form staphylococci? A. Catalase B. Coagulase C. Modified oxidase D. Novobiocin susceptibility
Correct Answer: C
Which one of the following organisms is a known producer of B-lactamase-producing strains, and should be tested (screened) by a commercial B-lactamase assay prior to susceptibility testing? A. Streptococcus pneumoniae B. Group B streptococci C. Enterococcus spp. D. Planococcus spp.
Correct Answer: C
Which organism is the most often recovered gram-positive cocci (catalase negative) from a series of blood cultures obtained from individuals with endocarditis? A. Streptococcus agalactiae B. Clostridium perfringens C. Enterococcus faecalis D. Pediococcus spp.
Correct Answer: C
"Cultures of parasites are different from bacterial cultures; no quality control is needed." This statement is: A. True, if two tubes of media are set up for each patient B. True, if the media are checked every 24 hours C. False, unless two different types of media are used D. False, and organism and media controls need to be set up
Correct Answer: D
A 12-year0old girl is brought to the emergency department with meningitidis and a history of swimming in a warm-water spring. Motile amoebae that measure 10u in size are seen in the CSF and are most likely: A. Iodamoeba butschlii trophozoites B. Endolimax nan trophozoites C. Dientamoeba fragilis trophozoites D. Naegleria fowleri trophozoites
Correct Answer: D
A 25-year-old male patient was diagnosed with HIV-1 by enzyme immunoassay, testing positive twice, and the diagnosis was confirmed by Western blot testing. Which laboratory test should be performed prior to initiating antiviral therapy? A. Quantitative plasma virus concentration (viral load testing) B. Quantitation of CD4 lymphocytes C. Phenotype/genotype resistance testing D. All of these options
Correct Answer: D
A 29-year-old male who often hunted rabbits and spent a lot of time in the woods was admitted to the hospital with skin ulcers on his upper extremities. At 48 hours, a small coccobacillus was recovered from the aerobic blood culture bottle only. The organism stained poorly with Gram stain, but did stain with acridine orange. Cultures taken from the ulcers did not grow on primary media. What is the most likely identification? A. Pseudomonas aeruginosa B. Pseudomonas fluorescens C. Chryseobacterium spp. D. Francisella tularensis
Correct Answer: D
A 3-year-old female was admitted to the hospital following a 2-day visit with relatives over the Christmas holidays. Vomiting and diarrhea left the child severely dehydrated. No other members of the family were affected. All bacterial cultures proved negative. A stool sample should be tested for which virus? A. CMV B. EBV C. Hepatitis D D. Rotavirus
Correct Answer: D
A 45-year-old hunter developed fever, myalgia, and periorbital edema. He has a history of bear meat consumption. The most likely causative agent is: A. Toxoplasma gondii B. Taenia solium C. Hymenolepis nana D. Trichinella spiralis
Correct Answer: D
A 49-year-old man who traveled to Mexico City returned with a bad case of dysentery. His symptoms were fever; abdominal cramping; and bloody, mucoidal, frequent stools. In addition to this, many WBCs were seen on the Gram stain smear. Stool culture gave the following results: -Gram stain: Gram-negative rods -Indole=+ -Urease=Neg -Lactose=+ -Lysin decarboxylase=Neg -Motility=Neg What is the most likely organism? A. Salmonella spp. B. Proteus mirabilis C. Escherichia coli D. Enteroinvasive E. coli (EIEC)
Correct Answer: D
A 60-year-old Brazilian patient with cardiac irregularities and congestive heart failure suddenly dies. Examination of the myocardium revealed numerous amastigotes, an indication that the cause of death was most likely: A. Leishmaniasis with Leishmania donovani B. Leishmaniasis with Leishmania braziliense C. Trypanosomiasis with Trypanosoma gambiense D. Trypanosomiasis with Trypanosoma cruzi
Correct Answer: D
A 65-year-old female outpatient was requested by her physician to submit a 24-hour urine specimen for protein and creatinine tests. He also requested testing for mycobacteria in the urine. Should the microbiology laboratory accept this 24-hour specimen for culture? A. Yes, if the specimen is kept on ice B. Yes, if the specimen is for aerobic culture only C. No, the specimen must be kept at room temperature D. No, the specimen is unsuitable for the recovery of mycobacteria
Correct Answer: D
A 65-year-old woman was admitted to the hospital with acute respiratory distress, fever, myalgia, and headache. Influenza A or B was suspected after ruling out bacterial pneumonia. Which of the following methods could be used to confirm influenza infection? A. influenza virus culture in Madin Darby canine kidney B. Hemagglutination-inhibition test for antibodies in the patient's serum C. Direct examination of nasal epithelium for virus using fluorescent antibody stain D. All of these options
Correct Answer: D
A 69-year-old male patient who was a cigarette smoker visited the doctor's office complaining of a cough and congestion of the lungs. Routine cultures of early morning sputum (X3) for bacteria as well as for AFB revealed no pathogens. A fungal culture was also ordered that grew the following on Sabouraud dextrose agar after 3 days: -Hyphae=Septate with dichotomous branching -Spores=Produced by conidial heads with numerous conidia -Colonies=Velvety or powder, white at firs, then turning dark greenish to gray (reverse=white to tan) -Vesicle= Holding phialides usually on upper two-thirds only What is the most likely identification? A. Aspergillus niger B. Absidia spp. C. Mucor spp. D. Aspergillus fumigatus
Correct Answer: D
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
Correct Answer: D
A catalase-positive, gram-positive coccus (clusters on Gram-stain smear) grew pale yellow, creamy colonies on 5% sheep blood agar. The specimen was recovered from pustules on the face of a 5-year-old girl with impetigo. The following test reactions indicate which organism? -Glucose=+ (Fermentation) -PYR=Neg -Lysostaphin=Sensitive -Oxidase=Neg -Bacitracin=Sensitive A. Micrococcus spp. B. Streptococcus spp. C. Enterococcus spp. D. Staphylcoccus spp.
Correct Answer: D
A clinical test used for the detection and identification of viral infections other than culture is: A. Hemagglutination B. Hemadsorption C. Viral antigen detection D. All of these options
Correct Answer: D
A gram-negative coccobacillus was recovered on chocolate agar from the CSF of an immunosuppressed patient. THe organism was nonmotile and positive for indophenol oxidase but failed to grow on MacConkey agar. The organism was highly susceptible to penicillin. The most probable identification is: A. Acinetobacter spp. B. Pseudomonas aeruginosa C. Pseudomonas stutzeri D. Moraxella lacunata
Correct Answer: D
A gram-positive (gram-variable), beaded organism with delicate branching was recovered from the sputum of a 20-year-old patient with leukemia. The specimen produced orange, glabrous, waxy colonies on Middlebrook's agar that shoed partial acid-fast staining with the modified Kinyoun stain. What is the most likely identification? A. Rhodococcus spp. B. Actinomadura spp. C. Streptomyces spp. D. Nocardia spp.
Correct Answer: D
A leg culture from a nursing home patient grew gram-negative rods on MacConkey agar as pink to dark pink oxidase=negative colonies. Given the following results, which is the most likely organism? -TIS=A/A -VP=+ -Urease=+ -Indole=Neg -Citrate=+ -Motility=Neg -MR=Neg -H2S=Neg Antibiotic susceptibility: resistant to carbenicillin and ampicillin A. Serratia marcescens B. Proteus vulgaris C. Enterobacter cloacae D. Klebsiella pneumoniae
Correct Answer: D
A patient is being seen in the emergency department for a low-grade fever, headache, and general malaise after returning from African on a photographic safari. The physician has requested blood for malaria; the laboratory would like to have patient information regarding: A. Specific travel history and body temperature every 4 hours B. Liver function tests and prophylactic medication history C. Transfusion history and body temperature every 4 hours D. Prophylactic medication history and specific travel history
Correct Answer: D
A patient with a human bite wound on the right forearm arrived at the clinic for treatment. The wound was inflicted 36 hours earlier, and a culture was taken by the physician on duty. After 48 hours, the culture result were: -Gram-stain smear=Gram-negative straight, slender rods -Chocolate agar plate="Pitting" of the agar by small, yellow, opaque colonies -Oxidase=+ -Glucose=+ -Growth in increased CO2=+ -Motility=Neg -Growth at 42C=Neg What is the most likely identification of this facultative anaerobe? A. Pseudomonas aeruginosa B. Acinetobacter baumannii C. Kingella kingae D. Eikenella corrodens
Correct Answer: D
A pregnant 25-year-old female with genital lesions delivered a premature newborn with complications. The baby tested negative for bacterial infection (cultures of blood and urine). Antigen testing of the baby's urine proved negative for group B streptococci and Streptococcus pneumoniae. The mother tested negative for bacterial sexually transmitted diseases and for group B streptococci. The baby was treated with acyclovir and failed to survive. What was the most likely cause of death? A. CMV B. Human immunodeficiency virus C. Respiratory syncytial virus D. Herpes simplex virus
Correct Answer: D
Which of the following organism will display lipase activity on egg yolk agar? A. Clostridium botulinum B. Clostridium sporogenes C. Clostridium novyi (A) D. All of these options
Correct Answer: D
A pure culture of B-hemolytic streptococci recovered from a leg wound ulcer gave the following reactions: -CAMP test=Neg -Bile esculin=Neg -PYR=Neg -Optochin= Resistant -Hippurate hydrolysis=Neg -6.5% salt=Neg -Bacitracin=Resistant -SXT=Sensitive The most likely identification is: A. Group A streptococci B. Group B streptococci C. Enterococcus faecalis D. Nongroup A, nongroup B, nongroup D streptococci
Correct Answer: D
A staphylococcus spp. recovered from a wound (cellulitis) was negative for the slide coagulase test (clumping factor) and negative for novobiocin resistance. The next test(s) needed for identification is (are): A. Tube coagulase test B. B-Hemolysis on blood agar C. Mannitol salt agar plate D. All of these options
Correct Answer: D
A suspected case of Legionnaires' disease was noted on the request form a culture and sensitivity ordered on a sputum sample. The patient was a 70-year-old male who presented with a positive serological test for Legionella spp. what is the most efficient way to confirm the infection using the submitted sample? A. Culture the sputum on MacConkey agar B. Gram stain of the sputum C. Acid-fast staining D. Direct immunofluorescent microscopy
Correct Answer: D
A suspected case of plague requires which of the following procedures in order to confirm Yersinia pestis? A. Collection of multiple sets fo blood cultures B. Incubation of blood cultures at both 28C and 35C C. Culture aspirates form bubos to MacConkey agar at room temperature D. All of these options
Correct Answer: D
A very small, single-stranded DNA virus that causes a febrile illnes with a rash and is called the fifth childhood disease after rubeola, rubella, varicella, and roseola is: A. Rotavirus B. Adenovirus type 40 C. Coxsackie A virus D. Parvovirus B19
Correct Answer: D
A yellow pigment-producing organism that is oxidase positive, nonmotile, and does not grow on MacConkey agar is: A. Acinetobacter baumannii B. Acinetobacter lwoffi C. Burkholderia cepacia D. Chryseobacterium meningosepticum
Correct Answer: D
After returning from a 2-year stay in India, a patient has eosinophilia, an enlarged left spermatic cord, and bilateral inguinal lymphadenopathy. The most likely clinical specimen and organism match is: A. Thin blood films- Leishmania B. Urine- concentration for Trichomonas vaginalis C. Thin blood films- Babesia D. Thick blood films- microfilariae
Correct Answer: D
All of the following are appropriate when attempting to isolate N. gonorrheae from a genital specimen except: A. Transport the genital swab in charcoal transport medium B. Plate the specimen on modified Thayer-Marin (MTM) medium C. Plate the specimen on New York City or Martin-Lewis agar D. Culture specimens in ambient oxygen at 37C
Correct Answer: D
All of the following are examples of appropriate specimens for the recovery of fungi except: A. Tissue biopsy B. CSF C. Aspirate of exudate D. Swab
Correct Answer: 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.
Correct Answer: D
All of the following mycobacteria are associated with skin infections except: A. Mycobacterium marinum B. Mycobacterium haemophilum C. Mycobacterium ulcerans D. Mycobacterium kansasii
Correct Answer: D
An immunocompromised patient continues to have diarrhea after repeated ova and parasites (O&P) examination (sedimentation concentration, trichrome permanent stained smear) were reported as negative; organisms that might be responsible for the diarrhea include: A. Cryptosporidium spp., Giardia lamblia, and Cystoisospora belli B. Giardia lamblia, microsporidia, and Endolimax nana C. Taenia solium and Endolimax nana D. Crytosporidium spp. and microsporidia
Correct Answer: D
An oxacillin-disk screen test is used to detect Streptococcus pneumonia resistance to penicillin. Using Mueller-Hinton agar with 5% sheep blood and aa 1 ug oxacillin disk, what is the recommended inhibition zone size for penicillin susceptibility? A.>/= 5mm B. >/= 10mm C.>/= 15mm D.>/= 20mm
Correct Answer: D
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
Correct Answer: D
Anaerobic gram-positive, spore-forming bacilli were recovered from the feces of a chemotherapy patient with severe diarrhea. The patient had undergone antibiotic therapy 1 week prior. The fecal culture produced growth only on the CCFA plate. no aerobic growth on normal flora was seen after 48 hours. The following results were noted: -Kanamycin=Sensitive -Colistin=Resistant -Lipase=Neg -Indole=Neg -Catalase=Neg -Vancomycin=Sensitive -Lecithinase=Neg -Nitrate=Neg -Urease=Neg -Spores -CCFA agar=Growth of yellow, "ground-glass" colonies that fluoresce chartreuse (yellow-green) What is the correct identification? A. Clostridium perfringens B. Clostridium tetani C. Clostridium sordellii D. Clostridium difficile
Correct Answer: D
At which pH does the methyl red (MR) test became positive? A. 7.0 B. 6.5 C. 6.0 D. 4.5
Correct Answer: D
Autofluorescence requires no stain and is recommended for the identification of: A. Entamoeba histolytica cysts B. Toxoplasma gondii tachyzoites C. Dientamoeba fragilis trophozoites D. Cyclospora cayetanesis oocysts
Correct Answer: D
B-Hemolytic streptococci, not of group A or B, usually exhibit which of the following reactions? Bacitracin: Trimethoprim-sulfamethoxazole A. Susceptible; Resistant B. Resistant; Resistant C. Resistant, Susceptible D. Susceptible or resistant; Susceptible
Correct Answer: D
Blastoconidia; Pseudohyphae; Arthroconidia Crytococcus spp: +, Neg, Neg Candida spp.: +, +, Neg Trichosporon spp.: +, +, + Geotrichum: Neg, +, + Which of the following yeasts produces only blastoconidia on cornmeal Tween 80 agar? A. Candida spp. B. Trichosporon spp. C. Geotrichum spp. D. Crytococcus spp.
Correct Answer: D
C. neoformans; R. rubra; T. cutaneum; C. albicans Urease: +, +, +, Neg Germ tube: Neg, Neg, Neg, + Brown and black colonies on niger seed agar: +, Neg, Neg, Neg Which of the following yeast is characteristically positive for germ tube production? A. Candida tropicalis B. Candida kefyr (pseudotropicalis) C. Cryptococcus neoformans D. Candida albicans
Correct Answer: D
Culture on MTM media of a vaginal swab produced several colonies of gram-negative diplococci that were catalase and oxidase positive and Superoxol negative. Given the following carbohydrate reactions, select the most likely identification. -Glucose=+ -Maltose=+ -Sucrose=Neg -Fructose=Neg -Lactose=+ A. Neisseria gonorrhoeae B. Neisseria sicca C. Neisseria flavescens D. Neisseria lactamica
Correct Answer: D
Cycloserine-cefoxitin-fructose agar (CCFA) is used for the recovery of: A. Yersinia enterocolitica B. Yersinia intermedia C. Clostridium perfringens D. Clostridium difficile
Correct Answer: D
Cytochrome oxidase-positive, nonfermentative gram-negative bacilli were recovered from the stool of a cystic fibrosis (CF) patient. The isolates produced wet (mucoidy) colonies on blood agar. Which identification is most likely? A. Acinetobacter spp. B. Pseudomonas alcaligenes C. Pseudomonas stutzeri D. Pseudomonas aeruginosa
Correct Answer: D
Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of: A. Ammonia B. Urea C. CO2 D. Amines
Correct Answer: D
Direct spread of pneumonic plague disease occurs by which route? A. Fecal-oral route B. Rat bite C. Ingestion of contaminated tissue D. Inhalation of contaminated airborne droplets
Correct Answer: D
Four blood cultures were taken over a 24-hour period from a 20-year-old woman with severe diarrhea. The cultures grew motile (room temperature), gram-negative rods. A urine specimen obtained by catheterization also showed gram-negative rods, 100,000 col/mL. Given the following results, which is the most likely organism? -TSI=A/A gas -VP=Neg -H2S=Neg -Urease=Neg -Phenylalnine deaminase=Neg -Indole=+ -MR=+ -Citrate=Neg -Lysine decarboxylase=+ A. Proteus vulgaris B. Salmonella typhi C. Yersinia enterocolitica D. E. coli
Correct Answer: D
Gram-negative diplococci recovered form an MTM plate and giving a positive oxidase test can be presumptively identified as: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Neisseria lactamica D. All of these options
Correct Answer: D
Hepatitis B virus can be transmitted by: A. Acupuncture B. Tattoos C. Sexual contact D. All of these options
Correct Answer: D
How long should Mycobacterium tuberculosis-positive cultures be kept by the laboratory after identification and antibiotic susceptibility testing have been performed? A. 1-2 months B. 2-4 months C. 5-6 months D. 6-12 months
Correct Answer: D
Humans acquire infections with Diphyllobothrium latum adult worms by: A. Ingestion of freshwater crabs B. Skin penetration of cercariae C. Ingestion of water chestnuts D. Ingestion of raw freshwater fish
Correct Answer: D
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
Correct Answer: D
In a pediatric patient, the recommended clinial specimen for recovery of Enterobius vermicularis is the: A. Stool specimen B. Sigmoidoscopy scrapings C. Duodenal aspirates D. Series of Scotch tape preparations
Correct Answer: D
In the Kauffmann-White schema, the combined antigens used for serological identification of the Salmonella spp. are: A. O antigens B. H antigens C. Vi and H antigens D. O, Vi, and H antigens
Correct Answer: D
Members of the genus Cedeccea are best differentiated from Serratia spp. by which test result? A. Positive motility B. Positive urease C. Positive phenylalanime deaminase D. Negative DNase
Correct Answer: D
Microsporidia have been identified as causing severe diarrhea, disseminated disease in other body sites, and ocular infections. Routes of infection have been identified as: A. Ingestion B. Inhalation C. Direct contamination form the environment D. Ingestion, inhalation, and direct contamination
Correct Answer: D
Nutritionally variant streptococci (NVS) require specific thiol compounds, cysteine, or the active form of vitamin B6. Which of the following test supplies these requirements? A. CAMP test B. Bacitracin susceptibility test C. Bile solubility test D. Staphylococcal cross-streak test
Correct Answer: D
Obligate anaerobes, facultative anaerobes, and microaerophiles are terms referring to bacteria that require: A. Increased nitrogen B. Decreased CO2 C. Increased O2 D. Decreased O2
Correct Answer: D
Parasite stages that are immediately infective for humans on passage from the gastrointestinal tract include: A. Schistosoma spp. B. Toxoplasma gondii bradyzoites C. Giardia lamblia trophozoites D. Crytosporidium spp. oocysts
Correct Answer: D
Potential problems using EDTA anticoagulant and holding the blood too long prior to preparation of thick and thin blood films include: A. Changes in parasite morphology, loss of organism within several hours, and poor staining B. Loss of Schuffner's dots, poor adherence of the blood to the glass slide, and parasites beginning the vector cycle within the tube of blood C. Neither A nor B D. All of these options
Correct Answer: D
Rapid methods for identifying classic infection with M. tuberculosis include: A. Gas-liquid chromatography B. Nucleic acid probes C. Acid-fast smears D. All of these options
Correct Answer: D
Specimens for virus culture should be transported in media containing: A. Antibiotics and 5% sheep blood B. Saline and 5% sheep blood C. 22% bovine albumin D. Antibiotics and nutrient
Correct Answer: D
Staphylococcus aureus recovered from a wound culture gave teh following antibiotic sensitivity pattern by the standardized Kirby-Bauer method (S=sensitive; R=resistant): -Pencillin=R -Cephalothin=R -Vancomycin=S -Ampicillin=R -Cefoxitin=R -Methicillin=R Which is the drug of choice for treating this infection? A. Penicillin B. Ampicillin C. Cephalothin D. Vancomycin
Correct Answer: D
Staphylococcus epidermidis (coagulase negative) is recovered form which of the following sources? A. Prosthetic heart valves B. Intravenous catheters C. Urinary tract D. All of these options
Correct Answer: D
Which of the following organisms are transmitted to animals and humans after a tick bite? A. Leptospira B. Chlamydia and Mycoplasma spp. C. Neisseria sicca D. Ehrlichia and Anaplasma spp.
Correct Answer: D
The following results were obtained form a pure culture of gram-negative rods recovered form the pulmonary secretions of a 10-year-old cystic fibrosis patient with pneumonia: -Oxidase=+ -Glucose OF (open)=+ -Pigment=Red (nonfluorescent) -Growth at 42C=+ -Motility =+ -Gelatin hydrolysis=+ -Arginie dihydrolase=+ Flagella=+ (polar, monotrichous) Which is the most likely organism? A. Burkholderia pseudomallei B. Pseudomonas stutzeri C. Burkholderia cepacia D. Pseudomonas aeruginosa
Correct Answer: D
The incorrect match between disease and symptoms is: A. Paragonimiasis- hemoptysis B. Crytosporidiosis- watery diarrhea C. Toxoplasmosis in comprised host-central nervous system symptoms D. Enterobiasis-dysentery
Correct Answer: D
The incorrect match between organism and characteristic is: A. Dientamoeba fragilis- tetrad karyosome in the nucleus B. Toxoplasma gondii- diagnostic serology C. Echinococcus granulosus- daughter cysts D. Schistosoma mansoni- egg with terminal spine
Correct Answer: D
The incorrect match between symptoms and disease is: A. Dysentery- amebiasis B. Malabsorption syndrome- giardiasis C. Cardiac involvement- chronic Chagas disease D. Myalgias- trichuriasis
Correct Answer: D
The most common viral syndrome of pericarditis, myocarditis, and pleurodynia (pain upon breathing) is caused by: A. Herpes simplex virus B. Respiratory syncytial virus C. Epstein-Barr virus D. Coxsackie B virus
Correct Answer: D
The quellung test is used to identify which Streptococcus species? A. S. pyogenes B. S. agalactiae C. S. sanguis D. S. pneumoniae
Correct Answer: D
The salt tolerance test (6.5% salt broth) is used to presumptively identify: A. Streptococcus pneumoniae B. Streptococcus bovis C. Streptococcus equinus D. Enterococcus faecalis
Correct Answer: D
Toxoplasma gondii is characterized by: A. Possible congenital infection and ingestion of oocysts B. Cosmopolitan distribution and possible difficulties with interpretation of serological results C. Neither A nor B D. Both A and B
Correct Answer: D
Upon direct examination of a sputum specimen, several spherules were noted that contained endospores. Growth on Sabouraud-dextrose agar showed aerial mycelial elements. The septate hyphae produced barrel-shaped arthroconidia. What is the most likely identification? A. Penicillium marneffei B. Scopulariopsis spp. C. Cryptococcus neoformans D. Coccidioides immittis
Correct Answer: D
Urine cultured from the catheter of an 18-year-old female patient produced more than 100,00 col/mL on a CNA plate. Colonies were catalase positive, coagulase negative by the late agglutination slide method as well as the tube coagulase test. The best single test for identification is: A. Lactose fermentation B. Urease C. Catalase D. Novobiocin susceptibility
Correct Answer: D
Variation in colony types seen with fresh isolates of Neisseria gonorrhoeae and sometimes with Neisseria meningitidis are the result of: A. Multiple nutritional requirements B. Pili on the cell surface C. Use of a transparent medium D. All of these options
Correct Answer: D
What is the first step to be performed in the identification of an unknown yeast isolate? A. Gram stain smear B. India ink stain C. Catalase test D. Germ tube test
Correct Answer: D
What is the most common cause of mucormycosis infection in humans? A. Penicillium spp. B. Candida albicans C. Scopulariopsis spp. D. Rhizopus spp.
Correct Answer: D
Which Bacteroides spp. is noted for "pitting" of the agar and is sensitive to penicillin 2-unit disks? A. B. vulgatus B. B. ovatus C. B. thetaiotaomicron D. B. ureolyticus
Correct Answer: D
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
Correct Answer: D
Which class of antibiotics is used for the treatment of serious gram-negative infection as well as infections with Mycobacterium tuberculosis? A. Cephalosporins B. Penicillins C. Tetracyclines D. Aminoglycosides
Correct Answer: D
Which group of tests best differentiates Helicobacter pylori and C. jejuni? A. Catalase, oxidase, and Gram stain B. Catalase, oxidase, and nalidixic acid sensitivity C. Catalase, oxidase, and cephalothin sensitivity D. Urease, nitrate, and hippurate hydrolysis
Correct Answer: D
Which group of tests, along with colonial morphology on primary media, aids most in the rapid identification of the Enterobacteriaceae? A. MR and VP, urease, and blood agar plate B. Phenylalanine deaminase, urease, and CDC agar plate C. Bacitracin, B-lactamase, and MacConkey agar plate D. Indole, oxidase, MacConkey, and blood agar plates
Correct Answer: D
Which is the specimen of choice for proof of food poisoning by Bacillus cereus? A. Sputum B. Blood C. Stool D. Food
Correct Answer: D
Which media should be used to recover Bordetella pertusis from a nasopharyngeal specimen? A. Chocolate agar B. Blood agar C. MacConkey agar D. Bordet-Gengou agar
Correct Answer: D
Which medium is best for recovery of Legionella pneumophila from clinical specimens? A. Chocolate agar B. Bordet-Gengou agar C. New yeast extract agar D. Buffered charcoal-yeast extract (CYE) agar
Correct Answer: D
Which nonpathogenic Mycobacterium specie is isolated most ofter form clinical specimens and is called the "tapwater bacillus"? A. M. kansasii B. M. avium-intracellulare complex C. M. leprae D. M. gordonae
Correct Answer: D
Which of the following drugs are first-line antibiotics used to treat classic tuberculosis for which susceptibility testing is perfromed by the disk diffusion method on Middlebrook 7H10 or 7H11 agar plates? A. Ampicillin, penicillin, streptomycin, and carbenicillin B. Ampicillin, penicillin, and methicillin C. Vancomycin, methicillin, and carbenicillin D. Isonicotinic acid hydrazide (INH), rifampin, ethambutol, and pyrazinamide
Correct Answer: D
Which of the following is a key characteristics of the thick blood film? A. The ability to see the parasite within the RBCs B. The ability to identify the parasites to the species level C. The examination of less blood than the thin blood film D. The necessity to lake the RBCs during or prior to staining
Correct Answer: D