Microbiology

This member of the Enterobacteriacea gave these reactions: TSIA. . A/A, gas (+), no H2S Ornithine . . . . Negative Lysine . . . . Positive Citrate . . . . Positive Urea . . . . Positive Phenylalanine . .Negative Motility . . . . . . . Negative a.Enterobacter cloacae b.Klebsiella pneumoniae c.Escherichia coli d.Yersinia enterocolitica

Klebsiella pneumoniae

What is the probable identity of an organism isolated from a wound culture that demonstrates the following test results?Phenylalanin Deaminase = negativeTSI - A/A gasCitrate = positiveLysine = positiveSIM = negative/negative/negativeUrea = weakly positive Select one: a.Escherichia coli b.Klebsiella pneumoniae c.Enterobacter aerogenes d.Proteus vulgaris e.Salmonella spp.

Klebsiella pneumoniae

The bacterial species producing the swarming on the surface of the 5% sheep blood agar plate shown in the photograph was indole negative. The most likely identification is: Select one: a.Morganella marganii b.Proteus mirabilis c.Proteus vulgaris d.Providenci rettgeri #28

Proteus mirabilis

The reactions observed in this Kligler Iron Agar slant (left) and Christensen's urease slant (right) provide the presumptive identification of: Select one: a.Citrobacter freundii b.Edwardsiella tarda c.Salmonella typhimurium d.Proteus mirabilis #27

Proteus mirabilis

The reactions observed in this Kligler Iron Agar slant (left) and Christensen's urease slant (right) provide the presumptive identification of: Select one: a.Citrobacter freundii b.Edwardsiella tarda c.Salmonella typhimurium d.Proteus mirabilis #56

Proteus mirabilis

If a Brucella species is suspected in a blood culture it should be held for a maximum of how many days on a commercial blood culture system? Select one: a.2-5 b.5-7 c.10-14 d.14-21

10-14

The top image is characteristic of the clinical presentation of oro-pharygeal thrush that may be observed in patients with AIDS. Specimen samples sent to the mycology laboratory for culture often grow yeast colonies on agar plates within 2-3 days of incubation at 30˚ C. Observed in the bottom photograph is the surface of a niger seed agar plate on which are growing inoculation streaks of two different yeast species, the one to the left representing the clinical isolate, the one to the right a control strain. It is important to recognize the colonies of the clinical isolate as it may be potentially resistant to commonly used anti-fungal agents. Select one: a.Candida dubliniensis b.Candida glabrata c.Candida albicans d.Candida parasilosis

Candida dubliniensis

Except for its two day rapid growth on SABHI agar incubated at 30° C, the hair-like gray-white colony illustrated in the top photograph, consistent with a Zygomycete, was recovered in culture as an environmental contaminant of a skin ulcer. The species identification can be made from the lactophenol blue stained microscopic mount seen in the bottom photomicrograph. From these observations, select from the multiple choices the name of this isolate. Select one: a.Circinella species b.Rhizopus species c.Cunninghamella species d.Syncephalastrum species #99

Circinella species

A major difference between Salmonella enterica and Shigella infections is that ONLY in salmonellosis can which of the following be observed? Select one: a.Animals serve as a reservoir of infection b.Diarrhea becomes the major symptom c.Endotoxin plays a role in the disease process d.Exotoxin produces profuse, watery stools

Animals serve as a reservoir of infection

Illustrated in these paired photomicrographs are acid fast stains of tissue sections of colon obtained from an AIDS patient with chronic diarrhea, illustrating a heavy infiltration with acid-fast bacilli (upper image), literally engorging the submucous macrophages (lower image). The Mycobacterium species most commonly associated with this infection is: Select one: a.Mycobacterium gordonae b.Mycobacterium tuberculosis c.Mycobacterium bovis d.Mycobacterium avium intracellulare complex #85

Mycobacterium avium intracellulare complex

______________________ is predominantly associated with skin and soft tissue infections (SSTIs), such as abscesses, cellulitis, folliculitis, and impetigo. Select one: a.Hospital-associated MRSA b.Community-associated MRSA

Community-associated MRSA

A recto-sigmoidoscopy revealed pseudomembranes in a patient with severe diarrhea following prolonged treatment with ampicillin. Which of the following organisms is MOST likely to be isolated? Select one: a.Bacteroides fragilis b.Clostridium botulinum c.Costridium difficile d.Fusobacterium nucleatum e.Klebsiella oxytoca

Costridium difficile

The infective stage for the majority of all intestinal amoebae is the: Select one: a.Trophozoite b.Cyst c.Larva d.Egg

Cyst

The image illustrates a Gram stain of a vaginal smear obtained from an 11-year-old girl suspected of being a victim of sexual abuse. The appearance of intracellular gram-negative diplococci (GNDC), as seen in the segmented neutrophil at the tip of the arrow, can represent different organisms. Therefore, recovery of the bacterial species in culture and biochemical identifications is needed before the case can be resolved. Each of the following may appear as intracellular GNDC EXCEPT for which organism? a.Neisseria gonorrhoeae b.Moraxella osloensis c.Acinetobacter baumannii d.Gardnerella vaginalis

Gardnerella vaginalis

Detection of antigens in clinical specimens when parasites are observed in stool specimens is the current test of choice for identification when a diagnosis is in doubt, providing an increased sensitivity over more common microscopy techniques. Several commercial products (DFAs, EIAs, and rapid tests) are available. Illustrated in the photomicrograph is an H & E - stained tissue section of duodenum illustrating the presence of an intra-luminal intestinal trophozoite in which an antigen assay of duodenal fluid might be helpful in making a definitive identification. Select from the multiple choices the presumptive identification. Select one: a.Chilomastix mesnili b.Giardia duodenalis c.Dientamoeba fragilis d.Trichomonas hominis #42

Giardia duodenalis

Infectious disease processes in which large numbers of activated macrophages and histiocytes are collected at the site of inflammation is called: Select one: a.Purulent b.Granulomatous c.Chronic d.Opportunistic

Granulomatous

Surprise. The purulent exudate the intracellular bacteria (shown by the arrows) as illustrated in this photomicrograph was observed in a direct sputum Gram stain of a 70 year-old patient with chronic obstructive pulmonary disease. The bacterial species that most likely grew out in culture is: Select one: a.Moraxella catarrhalis b.Neisseria gonorrhoeae c.Neisseria meningitidis d.Acinetobacter lwoffi #64

Moraxella catarrhalis

The Xylose Lysine Decarboxylase medium shown in this photograph was isolated from a stool specimen on an immunocompetent adult. Your best action would be to: Select one: a.Work it up for possible Yersinia enterocolytica b.Work it up for possible Salmonella spp. c.Serotype it for Escherichia coli O 157:H7 d.Report it as no Salmonella or Shigella isolated. #80

Report it as no Salmonella or Shigella isolated.

Which of these laboratory methods are recommended for confirmation of influenza A H1N1 subtype infection? Select one: a.Immunofluorescence assay (IFA) b.Reverse transcriptase-polymerase chain reaction (RT-PCR) c.Rapid influenza A/B test

Reverse transcriptase-polymerase chain reaction (RT-PCR)

Which one of the following does NOT have capsular material as a defense mechanism? Select one: a.H. influenza b.K. pneumonia c.N. meningitides d.S. aureus e.S. pneumonia

S. aureus

In observing the slow-growing , 7-day-old dark brown colonies growing on Sabouraud Dextrose with Grain Heart Infusion (SABHI) agar, note the black pigment that extends to the reverse of the colony. This provides for a presumptive indication of one of the fungi involved in chromoblastomycosis. The species identification of this fungus can be made by observing the distinctive fruiting heads illustrated in the bottom image. From the list of choices below, select the identification of the fungal species presented. Select one: a.Fonsecaea pedrosoi b.Exophiala jeanselmei c.Phialophora verrucosa d.Cladophialophora carrionii #48

* NOT Cladophialophora carrionii

Surprise! Animals are not the only creatures with bacteria. The bacterial species causing onion rot is: Select one: a.Shewanella putrifaciens b.Burkholderia cepacia c.Pantoea agglomerans (Erwinia herbicola) d.Klebsiella planticola

*Burkholderia cepacia NOT Pantoea agglomerans (Erwinia herbicola)

Which of the following are useful serological tests to document antecedent Streptococcal infections: Select one or more: a.ASO b.anti-DNAse c.M-antigen d.Hemolysin

A and B

The fungus illustrated in this photomicrograph was recovered from an induced sputum specimen from a 74 year old man with chronic obstructive pulmonary disease. This isolate is most likely: Select one: a.The cause of chronic bronchitis b.The cause of invasive pulmonary disease c.The cause of allergic bronchopulmonary disease d.A contaminant #65

A contaminant

Illustrated in the H & E - stained section in the top photomicrograph is a fungal form observed in tissue section of a biopsy taken from a clinical "fungus ball" infection of the lung. Note the distinctive funnel-like expansion of the terminal conidiophore and wide terminal columella suggestive of one of the Zygomycetes. The presumptive identification is confirmed by the bottom photomicrograph of the microscopic appearance of a mount prepared from the mycelium of the mold that was recovered. With these observations, select from the multiple choices the name of this fungal isolate. Select one: a.Circinella species b.Rhizopus species c.Absidia species d.Mucor species #128

Absidia species

Which nitrogenous base would bind with thymine in forming double-stranded DNA? Select one: a.Adenine b.Cytosine c.Uracil d.Guanine

Adenine

Which of the following test(s) that are the most useful in separating Listeria monocytogenesfrom Erysipelothrix rhusiopathiae? Select one: a.Room temperature motility b.Catalase c.Esculin hydrolysis d.All of the above

All of the above

Illustrated in the upper left image of the composite photograph is 3 day old colony with a central, granular yellow surface surrounded by a broad white apron. This colony was recovered from a fungus ball infection of the lung. The microscopic presentation of a methylene-blue stained mount of a sample from the surface of the colony is observed in the upper right and lower left images. In the lower right image taken of a dig-mount of the colony showing vegetative hyphae. With these observations, select from the list of multiple choice responses the fungal species as presented. Select one: a.Penicillium species b.Aspergillus fumigatus c.Paecilomyces species d.Aspergillus terreus #119

Aspergillus terreus

Illustrated in the top image are small, entire gray-white colonies growing on the surface of an anaerobic blood agar plate. Hemolysis is absent. Small, gram negative coccobacilli with rounded ends are seen on gram stain. Positive biochemical reactions include strong hydrolysis of esculin, positive indole and the fermentation of glucose and other carbohydrates (saccharolytic). From these observations, select the correct identification of this isolate from the choices below: Select one: a.Veillonella parvula b.Prevotella melaninogenica c.Bacteroides fragilis d.Fusobacterium nucleatum #73

Bacteroides fragilis

A beta-hemolytic Streptococcus was isolated from a throat culture. It gave the following biochemical reactions:· Bacitracin - Susceptible· Bile esculin - Negative· 6.5% NaCl - No growth· CAMP - Negative· SXT - ResistantWhat is the presumptive identification? Select one: a.Beta Streptococcus, group B b.Beta Streptococcus, not group A, B, or D c.Beta Streptococcus, group G d.Beta Streptococcus, group A

Beta Streptococcus, group A

Illustrated in the top image is a 10-day-old colony growing on the surface of Sabouraud Dextrose with Brain Infusion (SABHI) agar, incubated at 30 degrees C, recovered from an induced septum sample obtained from a 42-year-old Mid-western farmer. The colonies are not genus/species specific, and appear as a mold with a delicate, silky, cob-web like yellow-white mycelium. The species identification is made by observing the Lactophenol blue-stained tease mount preparation illustrated in the bottom image. With these observations, select the presumptive identification of this isolate from the choices shown below. Select one: a.Blastomyces dermatitidis b.Coccidioides immitis c.Histoplasma capsulatum d.Paracoccidioides brasiliensis #53

Blastomyces dermatitidis

A gram-negative coccobacillus produces small gray colonies surrounded by a zone of hemolysis on a potato-blood-glycerol agar. The organism also grew on chocolate agar, but NOT on sheep blood agar. This is MOST likely to be which organism? Select one: a.Alcaliqenes fecalis b. Bordetella pertussis c.Franciscella tularensis d.Hemophilus influenza e.Yersinia pestis

Bordetella pertussis

Illustrated in the upper photograph of the composite is the surface of a blood agar plate on which small, entire, gray-yellow colonies are observed, with yellow pigmentation shown on the cotton swab. Light pink, non-fermentative colonies are seen on MacConkey agar (composite upper right), confirmed by the Alk/Alk reaction on KIA (left tube in composite lower image). Shown in this composite also are key reactions - positive lysine decarboxylase (center), and oxidative utilization of maltose and sucrose (right). This non-fermenter is most commonly an opportunistic pathogen in cases of respiratory infection associated with chronic granulomatous disease and cystic fibrosis. From these observations, select from the multiple choices the identification of this isolate. Select one: a.Moraxella catarrhalis b.Burkholderia cepacia c.Alcaligenes faecalis d.Acinetobacter baumannii #110

Burkholderia cepacia

Spinal fluid cultures on a 3-day-old infant revealed beta-hemolytic, Gram-positive cocci occurring in pairs and chains. The organism was catalase-negative and bile esculin-negative. Resistance to 0.04 U disk of bacitracin was noted. The other test necessary to identify this organism is a positive test by: Select one: a.Bile solubility b.CAMP c.Coagulase d.PYR

CAMP

A decrease in which of the following in AIDS patients results in increased susceptibility to infection: Select one: a.CD 4+ cells b.CD 8+ cells c.HIV antibodies d.HIV antigens

CD 4+ cells

A small, microaerophilic, curved, gram-negative rod which was isolated from a diarrhea stool specimen gave the following results: Grew best at 42 ˚C Oxidase positive Resistant to cephalosporin Susceptible to nalidixic acid Hippurate hydrolysis positive What is the MOST probable identification of this organism? Select one: a.Campylobacter jejuni b.Campylobacter coli c.Salmonella species d.Vibrio cholera

Campylobacter jejuni

Trypanosoma cruzi is the etiologic agent of: Select one: a.African sleeping sickness b.relapsing fever c.filariasis d.kala-azar e.Chagas' disease

Chagas' disease

The media used to isolate Legionella pneumophilia should contain which of the following additives? Select one: a.X and V factors b.Hemin and vitamin K c.Charcoal and yeast extract d.Dextrose and laked blood e.Lactose and vitamin E

Charcoal and yeast extract

The irregular-sized, gray-white colonies, with irregular margins as shown in the image to the left in the upper composite photograph were recovered from a stool specimen in a case of antibiotic associated colitis. The colonies are flat, gray-white and spreading with irregular margins. Some patients with this infection develop pseudo-membranous colitis that can be life threatening. Growth is enhanced when Cycloserine-cefoxitin-fructose agar (CCFA) is used, as seen in upper right photograph. The observation of elongated, gram positive bacilli with distinctive sub-terminal and central spores in gram stain mounts provides for a presumptive identification. An additional key identifying biochemical reaction is the hydrolysis of esculin and gelatin. With these observations, select from the multiple choices the presumptive identification of this isolate. Select one: a.Propionibacterium acnes b.Clostridium difficile c.Actinomyces Israeli d.Bacteroides fragilis #121

Clostridium difficile

The colonies illustrated on the blood and chocolate agar plates represent a slow-growing bacterial species that is endogenous in the oral cavity and upper respiratory tract, but may be recovered from human bite skin infections incurred during fist fights. Note the pitting of the agar surrounding the colonies growing in the chocolate agar plate. The Alk/Alk non fermentative reaction seen in the Kligler Iron Agar tube to the left in the lower photograph indicates the non fermentation of glucose, also indicated by the lack of carbohydrate assimilation in the individual carbohydrate reaction tubes to the right of the KIA tube. A reduction of nitrate demonstrated and decarboxylation of ornithine are the positive reactions included in this exercise. From these observations, select from the multiple choices identification of this bacterial isolate. #6

Eikenella corrodens

Which of the following statements about the HBV vaccine is INCORRECT? Select one: a.The vaccine is effective in 90% of cases b.Employers may require a fee to administer the vaccine c.Side effects are rare and minimal d.The vaccine is administered over a six-month period

Employers may require a fee to administer the vaccine

The 6 um in diameter cyst illustrated in the trichrome-stained photomicrograph was inadvertently observed in the stool specimen that was being examined for reasons not clinically related to a parasitic diseases. Further history revealed that the patient for whom the stool examination was being performed had only rare bouts of mild diarrhea. From the multiple choices listed below, select the appropriate genus/species designation to enter in the laboratory report to be sent out. Select one: a.Entamoeba histloytica b.Entamoeba coli c.Entamoeba dispar d.Entamoeba histolytica/dispar #81

Entamoeba histolytica/dispar

As a gram positive coccusI've become a bit fancy,Short chains and motile, plusI carry the gene VanC. Select one: a.Enterococcus faecium b.Staphylococcus aureus c.Enterococcus cassiloflavus d.Streptococcus pneumoniae

Enterococcus cassiloflavus

Which two of the following organisms are gram-positive? Select one or more: a. Pasturella b. Erysipelthrix c. Aeromonas d. Lactococcus

Erysipelthrix Lactococcus

Human papillomavirus (HPV) is a rare infection that always results in a malignant cancer. Select one: True False

False

The age groups that have been most affected by the H1N1 virus are children and younger adults. Select one: True False

False

Illustrated in the close-in high power microscopic view is a large spherical ovum measuring 130 um as it may appear in a mount of fecal material. These ova often have a brown staining that suggests passage through a biliary duct on its way through the large intestine. Identifying characteristics include a thin, smooth shell and an indistinct, flat, non-shouldered operculum (blue lines). From the appearance of this ovum, select from the multiple choices the presumptive identification. Select one: a.Fasciola hepatica b.Schistosoma haematobium c.Clonorchis sinensis d.Paragonimus westermani #102

Fasciola hepatica

A 30 year old man with chronic persistent hepatitis developed an abscess in the right hepatic lobe. A needle aspiration revealed purulent material. The small colonies shown in the upper photograph were isolated after 36 hours incubation at 35 degrees C. They emitted a butter scotch odor. The lower photomicrograph reveals the gram stain features. The antigen most likely carried by this isolate is: Select one: a.Group A b.Group B c.Group G d.Group F #79

Group F

Match the hepatitis B test with the appropriate disease phase. HBsAg Anti-HBs Anti-HBc Anti-HBc 1. IgM Acute, convalescent 2. Late incubation, acute 3. Recovery 4. Total Acute, convalescent, recovery

HBsAg= Late incubation, acute Anti-HBs= Recovery Anti-HBc= Recovery Anti-HBc= Late incubation, acute Anti-HBc= Total Acute, convalescent, recovery

Match the viruses below with their associated diseases Hepadnavirus Arbovirus Parvovirus Paramyxovirus

Hepadnavirus= Hepatitis Arbovirus= Encephalitis Parvovirus= Fifth disease Paramyxovirus= Measles-Mumps

The colonies shown in the upper image were obtained on blood agar from a sputum specimen after 10 days incubation at 30˚ C. The lower is a photomicrograph of a lactophenol blue mount made from a portion of the colony.The delicate cob-web appearance of the colonies on blood agar (upper image) and the production of macroconidia with a conspicuous prickly surface as seen in the lower image are characteristic of: Select one: a.Histoplasma capsulatum b.Coccidioides immitis c.Blastomyces dermatitidis d.Paracoccidiodes brasiliensis #126

Histoplasma capsulatum

The presumptive diagnosis of fungal infections mey be made based on the location of sites of visit in which they became endemic. One such condition, is colloquially referred to as "Spelunker's Scourge". This condition occurs after a tour or work in underground caves located in the Midwest, where dust contaminated with bird and bat dung is inhaled. endemically-acquired respiratory infection. Select one: a.Coccidioides immitis b.Histoplasma capsulatum c.Blastomyces dermatitidis d.Paracoccidioides brasilienses

Histoplasma capsulatum

The combination of organisms that is correctly paired with the reactions for appropriate quality control (one organism positive for the reaction and one organism negative for the reaction) are: Select one: a.Coagulase: Staphylococcus saprophyticus and Staphylococcus epidermidis b.H2S production: Proteus mirabilis and Salmonella c.Phenylalanine deamination: Escherichia coli and Yersinia enterocolytica d.Indole: Escherichia coli and Proteus mirabilis

Indole: Escherichia coli and Proteus mirabilis

Which substance acts as a mordant in the Gram Stain process? Select one: a.Acetone b.Crystal Violet c.Ethanol d.Iodine e.Safranin O

Iodine

Which one of the following comments about Francisella is not true? Select one: a.Can penetrate minute skin breaks b.Causes Tularemia c.Possesses a thin capsule d.Is a strict anaerobe e.Transmitted by tick bites

Is a strict anaerobe

The bacterial species illustrated in these photographs was recovered from septic peritoneal fluid of a patient undergoing continuous peritoneal dialysis. The most likely identification is: Select one: a.Micrococcus luteus b.Staphylococcus aureus c.Staphylococcus cohnii d.Stomatococcus mucilagenosus #16

Micrococcus luteus

The high power photograph was taken from a saline wet preparation of a stool specimen. The patient, a 45 year old male with AIDS who recently returned from a vacation to Mexico City, was suffering from recurrent diarrhea. Based on the morphology of the oocyst, select from the multiple choices the most probable presumptive identification. Select one: a.Giardia duodenalis b.Isospora belli c.Dientamoeba fragilis d.Chilomastix mesnili #62

Isospora belli

Which one of the following statements about Coxiella burnetii is not true: Select one: a.It causes Q fever b.It has a worldwide distribution c.It is an obligate intracellular parasite d.It is best diagnosed by culture of the organism

It is best diagnosed by culture of the organism

Which one of the following statements about Coxiella burnetti is not true: Select one: a.It causes Q fever b.It had a worldwide distribution c.It is an obligate intracellular parasite d.It is best diagnosed by culture of the organism

It is best diagnosed by culture of the organism

A 65 y/o male with type 2 diabetes presented to ED complaining of febrile episodes following his last dialysis treatment. The microscopic examination of his urine showed numerous white blood cells and bacteria. His urine was sent to the lab for culture and sensitivity. Urine colony count was >100,000 CFU/mL for a single organism that was identified as Klebsiella pneumoniae. Observe the reactions of this organism on the Kirby Bauer antibiotic susceptibility plate and review the susceptibility results on the AST report form. The Hodge Test was positive. Select from the multiple choices the resistance mechanism that this organism demonstrates. Select one: a.AmpC Beta Lactamase b.KPC - Klebsiella pneumoniae Carbapenemase c.K-1 Beta Lactamase d.ESBL (Extended-Spectrum Beta Lactamase) #88

KPC - Klebsiella pneumoniae Carbapenemase

The distinctly large, spreading mucoid colonies seen on blood agar in the upper left image, and the display of lactose fermentation on MacConkey agar in the upper right image provide for a presumptive identification. This species is most commonly recovered from respiratory specimens of patients with pneumonia. Observing a weak reaction for urea, and strong reactions for citrate and Voges Proskauer confirm the presumptive identification. From the multiple choices, select the name of the isolate presented in this exercise. Select one: a.Proteus mirabilis b.Edwardsiella tarda c.Citrobacter freundii d.Klebsiella pneumonia #114

Klebsiella pneumonia

A 30 year old Hispanic pregnant female developed fever and signs and symptoms of meningitis following ingestion of feta cheese sent by relatives in Mexico. The colonies recovered from a positive blood culture is shown in the upper photograph, the microscopic features in the lower photograph. The most likely identification is: Select one: a.Streptococcus agalactiae b.Listeria monocytogenes c.Brucella militensis d.Leuconostoc mesenteroides #45

Listeria monocytogenes

Small, gray-white colonies, as observed growing on 7-H10 agar to the left in the upper composite photograph, were recovered from an upper respiratory specimen after 7 days incubation. This Mycobacteriumspecies in the past was uncommonly recovered from human infections until the advent of AIDS when it became an agent of pulmonary and other infections. Notably, colony isolates from patients with AIDS have developed a pale yellow pigmentation that does not intensify with light exposure (right image in upper composite photograph). The acid-fast bacilli as observed in the lower photomicrograph are short and lie singly or in loose clusters. From these observations select from the multiple choices the presumptive identification of this isolate. Select one: a.Mycobacterium marinum b.Mycobacterium tuberculosis c.Mycobacterium avium/intracellulare d.Mycobacterium kansasii #44

Mycobacterium avium/intracellulare

As one of the aerobic actinomycetes, the light yellow, entire, convex, smooth, non hemolytic colonies are observed on blood agar. The gram stain, showing gram-positive bacilli, with filamentous forms seen in younger cultures, is not distinctive. Key to the identification is the hydrolysis of casein, as seen in the lower photograph. Xanthine was not hydrolyzed. The presumptive identification is: Select one: a.Rhodococcus equi b.Nocardia asteroides c.Oerskovia turbata d.Streptomyces species #32

Oerskovia turbata

The increased resistance of MRSA strains to beta-lactam antibiotics is due to production of which of the following penicillin binding proteins (PBPs)? Select one: a.PBP 2 b.PBP 2a c.PBP 3 d.PBP 4

PBP 2a

Recovered from a sputum sample, this suspicious form measures 112 micro meters by 55 micro meters. Select one: a.Schistosoma mansoni egg b.Paragonimus westermani egg c.Pneumocystis carinii cyst d.Diphyllobothrium latum egg #47

Paragonimus westermani egg

MacConkey agar contains all of the following except: Select one: a.Penicillin b.Bile salts c.Lactose d.Crystal violet

Penicillin

Which type of healthcare occupational exposure has the greatest risk of HIV transmission? Select one: a.Percutaneous injury b.Mucous membrane exposure c.Abraded skin exposure d.None of the above

Percutaneous injury

The suspicious form was recovered in blood. Please identify the species listed below that matches the parasites shown in the image with arrows. Select one: a.Plasmodium vivax b.Plasmodium malariae c.Plasmodium falciparum d.Pseudoparasite #39

Plasmodium falciparum

The condition most likely to predispose a person to septicemia by viridans streptococci is: Select one: a.Hypertrophy of the prostate gland b.Poor oral hygiene c.Chronic obstructive pulmonary disease d.Indwelling catheter

Poor oral hygiene

The colonies illustrated in the composite blood agar/MacConkey agar to the left were recovered from an inflammatory infection of the oral cavity of a 16-year-old student. The colonies on both agar plates incubated anaerobically are small, entire, and smooth with a light gray-yellow pigmentation. Small gram-negative rods arranged singly and in loose clusters had been observed microscopically in a gram-stained preparation. Spot indole and lipase reactions are positive. Note in the image to the right the alk/alk non-fermentative carbohydrate reaction on Kligler Iron agar, with lack of fermentation of the sugars presented in the tubes to the right (asaccharolytic). Select from the multiple choices the name of the anaerobic, asaccharolytic, gram-negative isolate. Select one: a.Porphyromonas asaccharolytica b.Fusobacterium nucleatum c.Bacteroides fragilis d.Propionibacterium acnes #113

Porphyromonas asaccharolytica

The colonies illustrated in the composite blood agar/MacConkey agar to the left were recovered from an inflammatory infection of the oral cavity of a 16-year-old student. The colonies on both agar plates incubated anaerobically are small, entire, and smooth with a light gray-yellow pigmentation. Small gram-negative rods arranged singly and in loose clusters had been observed microscopically in a gram-stained preparation. Spot indole and lipase reactions are positive. Note in the image to the right the alk/alk non-fermentative carbohydrate reaction on Kligler Iron agar, with lack of fermentation of the sugars presented in the tubes to the right (asaccharolytic). Select from the multiple choices the name of this anaerobic, asaccharolytic, gram-negative isolate. Select one: a.Porphyromonas asaccharolytica b.Fusobacterium nucleatum c.Bacteroides fragilis d.Propionibacterium acnes #107

Porphyromonas asaccharolytica

Match each virus with its appropriate nucleic acid content. RNA RNA DNA RNA 4Choose... Rhabdovirus Poxvirus Paramyxovirus Orthomyxovirus

RNA= Rhabdovirus RNA= Paramyxovirus DNA= Poxvirus RNA= Orthomyxovirus

Multiple young 3-day old colonies having a low cottony surface mycelium that upon maturity develop a distinctly gray pigmentation (referred to as "house mouse gray"). The reverse of the colony remains light gray in color and does not show the darker pigmentation. Microscopic examination of a small inoculums from the surface of the colony is illustrated in the lower photomicrograph. From the list of multiple choices, select the genus name of the fungus being represented. Select one: a.Beauveria b.Sepedonium c.Chrysosporium d.Scedosporium #36

Scedosporium

Multiple young 3-day old colonies having a low cottony surface mycelium that upon maturity develop a distinctly gray pigmentation (referred to as "house mouse gray"). The reverse of the colony remains light gray in color and does not show the darker pigmentation. Microscopic examination of a small inoculums from the surfaces of the colony is illustrated in the lower photomicrograph. From the list of multiple choices, select the genus name of the fungus being presented Select one: a.Beauveria b.Sepedonium c.Chrysosporium d.Scedosporium #82

Scedosporium

The ovum as illustrated in the high-power photomicrograph, averages 140 um. The ova are most commonly observed in a urine sediment from a patient complaining of frequent urination, dysuria, hematuria and recurrent urinary tract infections. Note the characteristic delicate, sharply pointed terminal spine (blue arrow) extruding from the anterior margin of the shell. From the multiple choices listed below, select the presumptive identification of this ovum. Select one: a.Schistosoma haematobium b.Schistosoma mansoni c.Fasciola hepatica d.Schistosoma japonicum #100

Schistosoma haematobium

The appearance of the bacterial colonies growing on the surface of the Hektoen Enteric agar plate shown in this photograph are consistent with each of the following bacterial species except: Select one: a.Serratia marcesens b.Shigella sonnei c.Klebsiella oxytoca d.Enterobacter sakasakii #58

Shigella sonnei

Which of the following are the most frequently associated with infective endocarditis? Select two of the choices provided. Select one or more: a.Viruses b.Neisseria c.Staphlyococci d.Streptococci

Staphlyococci Streptococci

Who are we huddled here so tight,Like clusters of stars in the night. Select one: a.Staphlyococcus epidermis b.Streptococcus milleri c.Corynebacterium xerosis d.Enterococcus faecium #78

Staphlyococcus epidermis

An infective agent of skin wound infections and an agent of toxic shock syndrome, the large, entire, golden-yellow, smooth convex colonies on blood agar were recovered from a swab specimen after 48 hours incubation at 37 degrees C. In the photomicrograph, clusters of gram-positive cocci were observed microscopically in a gram stain prepared from one of the colonies. The coagulase reactions are pictured in the lower images. Select one: a.Staphylococcus aureus b.Staphylococcus saprophyticus c.Micrococcus luteus d.Staphylococcus epidermidis #21

Staphylococcus aureus

This is a catalase-positive, coagulase-negative gram-positive coccus isolated from a urine specimen from a 20-year-old college student. The image below is a Mueller Hinton plate streaked with a 0.5 MacFarland standardized inoculum and a 5 microgram disk of novobiocin after overnight incubation. What is the identification of the isolate? Select one: a.Staphylococcus epidermidis b.Staphylococcus aureus c.Staphylococcus saprophyticus d.Staphylococcus lugdenensis

Staphylococcus saprophyticus

The observation of darkly pigmented colonies on blood agar as illustrated in this photograph is somewhat of a surprise. The colonies of each of the following bacterial species may have an appearance similar to that seen here except: Select one: a.Prevotella melaninogenica b.Stentotrophomonas maltophilia c.Chromobacterium violaceum d.Pseudomonas aeruginosa #13

Stentotrophomonas maltophilia

The Optochin (ethylhydrocupreine hydrochloride) disc is MOST often used for the identification of which organism? Select one: a.Staphylococci aureus b.Hemophilus influenzae c.Streptococci pyogenes d.Streptococci pneumoniae e.Staphylococci epidermidi

Streptococci pneumoniae

Tiny, gray-white colonies growing on the surface of chocolate agar were initially thought to be Haemophilusspecies. Consistent with this observation, streaks of colony growth had been observed adjacent to a beta hemolytic Staphylococcus test streak. A gram stain of this isolate is pictured here taken, from this blood agar plate. What presumptive identification can be made? Select one: a.Streptococcus viridans b.Streptococcus pneumonia c.Streptococcus anginosus (milleri) d.Enterococcus faecium #69

Streptococcus anginosus (milleri)

This isolate is a catalase negative, gram positive coccus on sheep blood agar. The P disk has 5 ug of optochin and the zone around it is 16 mm. It has been streaked perpendicular to a beta lysine-producing Staphylococcus aureus. The presumptive identification is: Select one: a.Streptococcus pneumoniae b.Streptococcus agalactiae c.Streptococcus pyogenes d.Viridans streptococcus #70

Streptococcus pneumoniae

Illustrated in the top photograph are alpha-hemolytic, entire, gray-white convex colonies that are of a bacterial species that was found to be susceptible to vancomycin. In the lower photomicrograph are shown gram-positive cocci arranged in chains and in loose clusters that are not species distinctive. Select from the multiple choices the bacterial species that are uncommonly vancomycin resistant. Select one: a.Staphylococcus species b.Leuconostoc species c.Pediococcus species d.Streptococcus species #115

Streptococcus species

What is the primary target of HIV? Select one: a.Heart b.Liver c.Lungs d.T-helper cells

T-helper cells

Illustrated in the composite photograph is an inflammatory reaction of skin with erythema and micro-pustule formation, most consistent with a dermatophyte infection. The lactophenol blue mount was prepared from a 4-day old colony grown from the skin lesion as shown. The accompanying lactophenol blue microscopic mount illustrates small, spherical micro conidia arranged in loose clusters along the sides of thin hyaline hyphae. The species identification can be confirmed by the positive urease reaction as shown. Select from these observations the species identification of this isolate. Select one: a.Microsporum gypseum b.Trichophyton mentagrophytes c.Microsporum canis d.Epidermophyton floccosum #96

Trichophyton mentagrophytes

Illustrated in the top photograph is the picture of a yellow to buff colored colony, suede-like in consistency, recovered from a hairless inflammatory lesion of the skin of the scalp of a young male athlete. The more definitive identification can be made from observation of the lactophenol blue mount illustrated in the bottom photomicrograph, prepared from a small sample of the colony surface mycelium. Based on these observations, select from the multiple choices the presumptive identification. Select one: a.Trichophyton mentagrophytes b.Microsporum gypseum c.Epidermophyton floccosum d.Trichophyton tonsurans #83

Trichophyton tonsurans

Illustrated in the top photograph is a small circular white colony with a downy surface, recovered from a skin scraping specimen after 7 days of growth on agar supplemented with thiamine and inositol. The identification is made by observing the aerial hyphae (middle frame) and the underlying chains of pigmented chlamydospores among the hyphae (lower frame) as seen in this composite image. With these observations, select the identification of this dermatophyte. Select one: a.Microsporum gypseum b.Trichophyton tonsurans c.Trichophyton verrucosum d.Epidermophyton floccosum #123

Trichophyton verrucosum

Any laboratory that analyzes microbes or refers specimens that have the potential to contain microbial agents or toxins is a sentinel laboratory. Select one: True False

True

The fastidious gram negative bacillus featured here has been recovered from individuals in pandemic outbreaks of diarrhea after ingestion of contaminated stream, lake, or well water. In many cses, life-threatening profuse diarrhea resulting in dehydration and electrolyte loss is often experienced. Smooth, entire, convex light gray yellow colonies are observed on blood agar (left upper image). Note the yellow pigmentation of the colonies growing on TCBS agar (Thiosulfate Citrate Bile Sucrose) on the right of the composite image, indicating strong acid production from sucrose. Cytochrome oxidase is also positive. Small, curved and S-shaped, gram-negative bacilli are seen on Gram stain. From these observations, select from the multiple choices the correct genus/species identification of this isolate. Select one: a.Aeromonas hydrophila b.Plesiomonas shigelloides c.Vibrio cholerae d.Non-Vibrio cholera #109

Vibrio cholerae

A small gram-negative rod isolated from an eye grows on chocolate agar but NOT on sheep blood agar. It produces satellite growth around staphylococci on sheep blood agar, however. The organism requires: Select one: a.X and V factor b.X factor only c.V factor only d.Neither X or V factor

X and V factor

The stool specimen from a patient admitted to the hospital with symptoms of appendicitis has a culture with the following characteristics:Gram-negative bacillusCatalase positiveUrease positiveWeakly fermentativeTSI Slant is A/AThese reactions suggest that the organism is MOST likely: Select one: a.Yerseinia enterocolitica b.Escherichia coli c.Plesiomonas shigelloides d.Pasteurella multocida

Yerseinia enterocolitica

In tissues infected with Histoplasma capsulatum, which of the following is usually true? Select one: a.hyphae usually invade blood vessels b.encapsulated yeast cells are typical c.conidiophores with metulae and phialides are typical d.fungus is usually intracellular

fungus is usually intracellular

An acid-fast bacillus is isolated and produces an orange pigment when grown in either the light or the dark. Which type of organism has most likely been isolated? Select one: a.photochromogen b.scotochromogen c.BCG d.Mycobacterium tuberculosis e.non-pathogeni

scotochromogen

Each of the following characteristics will differentiate between Listeria monocytogenes and Erysipelothrix rhusiopathiaeexcept: Select one: a.Hydrolsis of esculin b.Motility c.Catalase d.Fermentation of glucose

Fermentation of glucose

The mechanism by which certain strains of Enterococcusspecies have developed resistance to the synergistic combination of aminoglycoside and beta-lactam antibiotics is: Select one: a.Alteration of penicillin binding proteins b.Beta lactamase activity against the beta-lactam moiety c.High level gentamicin resistance d.Efflux of antibiotics from the bacterial cell

High level gentamicin resistance

The colonies shown in the upper image were obtained on blood agar from a sputum specimen after 10 days incubation at 30° C. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony.The delicate cob-web appearance of the colonies on blood agar (upper image) and the production of macroconidia with a conspicuous prickly surface as seen in the lower image are characteristic of: Select one: a.Histoplasma capsulatum b.Coccidioides immitis c.Blastomyces dermatitidis d.Paracoccidiodes brasiliensis #95

Histoplasma capsulatum

A flagellar strain would show peritrichous flagellae for each of the following organisms except: Select one: a.Bordetella bronchiseptica b.Alcaligenes faecalis c.Pseudomonas aeruginosa d.Escherichia coli

Pseudomonas aeruginosa

In molecular diagnostic testing, hybridization employs complementary base pair binding of a synthetic strand to DNA or RNA. Select one: True False

True

The fungal colonies illustrated in the left image grew to maturity in 4 days. The isolate was recovered from the expectorated sputum of an elderly immune-compromised patient. The image on the right is the microscopic appearance of a lactophenol blue stained mount prepared from a small sample from the surface of the colony. Note that microscopically the entire surface of a smooth spherical vesicle is surrounded by a row of phialides giving rise to small conidia. Select from the multiple choices the Aspergillusspecies represented by these observations. Select one: a.Aspergillus fumigatus b.Aspergillus flavus c.Aspergillus niger d.Aspergillus terreus #61

*Aspergillus flavus NOT Aspergillus niger

Within three days at 28°C a sputum specimen placed in Sabouraud's dextrose agar with chloramphenicol and cycloheximide produced moist, grayish growth, with a white aerial mycelium, the organism is MOST likely: Select one: a.Asperigillus fumigatus b.Blastomyces dermatitidis c.Coccidioides immitis d.Cryptococcus neoformans e.Histoplasma capsulatum

*Asperigillus fumigatus NOT Coccidioides immitis

Illustrated in the photograph is a bile esculin agar plate inoculated with a bacterial isolate from a urinary tract infection. The most likely identification is: Select one: a.Stenotrophomonas maltophilia b.Streptococcus mutans c.Enterococcus faecalis d.Bacteroides fragilis #71

*Enterococcus faecalis NOT Bacteroides fragilis

Which bacterial species is a common agent of neonatal bacteremia? Select one: a.Streptococcus pyogenes b.Listeria monocytogenes c.Staphylococcus aureus d.Enterococcus faecium

*Listeria monocytogenes NOT Staphylococcus aureus

Each of the following tests is helpful in the species identification of Staphylococcus aureus except: Select one: a.Thermostable endonuclease b.Deoxyribonuclease c.Modified dimethyl sulfoxide (DMSO) test d.Tube coagulase test

*Modified dimethyl sulfoxide (DMSO) test NOT Deoxyribonuclease

The entire, smooth, convex Mycobacterium species colonies growing on 7H10 agar were observed to be dark yellow pigmented early in culture even before having been exposed to light. This isolate was found to be Tween-80 positive as seen in the reaction tubes in the bottom photograph. Select from the multiple choices the presumptive identification of this isolate. Select one: a.Mycobacterium gordonae b.Mycobacterium fortuitum c.Mycobacterium kansasii d.Mycobacterium marinum #127

*Mycobacterium gordonae NOT Mycobacterium kansasii

An isolate of S. pneumoniae from a respiratory specimen gave a zone of inhibition of 18 mm around a 1 ug oxacillin using the disk diffusion test. What should the next step be? Select one: a.Report the isolate as penicillin sensitive b.Report the isolate as penicillin resistant c.Set up an MIC on the isolate d.Report the isolate as moderately susceptible

*Set up an MIC on the isolate NOT Report the isolate as moderately susceptible

Which of the following is a characteristic of Francisells tularensis? Select one: a.Tiny, weak-staining, gram-negative coccobacilli b.Oxidase and urease positive c.Subcultures grow easily and quickly on sheep bloor agar (SBA) d.Tiny, gram-positive rods

*Tiny, weak-staining, gram-negative coccobacilli NOT Tiny, gram-positive rods

Select from the multiple choices the specimen that is inadequate for the recovery of anaerobes and should be summarily rejected upon receipt in the microbiology laboratory. Select one: a.Swab specimens taken from of deep sub-cutaneous abscess b.Needle aspirate in an anaerobic E-swab tube c.Syringe aspirate hand-carried to microbiology laboratory d.Uterine cervical swab in Cary-Blair transport medium

*Uterine cervical swab in Cary-Blair transport medium NOT Swab specimens taken from of deep sub-cutaneous abscess

Illustrated in the photograph is what appears to be a tapeworm strobili in which the individual proglottids appear broader than long. If this segment was observed in a stool specimen, select from the multiple choices the presumptive identification. Select one: a.Diphyllobothrium latum b.Taenia saginata c.Hymenolepis nana d.Vegetable artifact

*Vegetable artifact NOT Diphyllobothrium latum

The light gray-white, border to border colony extension when covered in clinical specimen is usually considered as a Zygomycetecontaminant. In this exercise the recovery of this fungus may have been involved as a commensal in both skin and internal infections of patients with immune deficiency or who may have received recent chemotherapy or are post-surgery. The identification can be made by observing the fruiting bodies in the lactophenol blue mount illustrated in the photomicrograph to the right. From these observations, select from the multiple choice selections the name of this isolate. Select one: a.Circinella species b.Cunninghamella species c.Syncephalastrum species d.Rhizopus species #117

Cunninghamella species

The Mycobacterium species capable of growing on modified MacConkey agar (crystal violet removed from the formula), as illustrated in this photograph, is: Select one: a.Mycobacterium avium/intracellulare b.Mycobacterium kansasii c.Mycobacterium marinum d.Mycobacterium fortuitum

Mycobacterium fortuitum

Illustrated in this exercise are colonies growing on Middlebrook 7H10 agar before (lower) and after (upper) exposure to light. Colonies are intermediate between smooth and rough depending on the strain. Prior to exposure to light the colonies are gray white. Upon exposure to ambient light, visible yellow pigment production is observed characteristic of one of the "photochromogens", as illustrated in the top composite colony photograph, The acid-fast stain reveals slender acid fast bacilli with cross banding. Characteristic for the presumptive identification of this isolate are positive reactions for several biochemical reactions - nitrate reduction, Tween 80 hydrolysis, catalase, urease and pyrazinamidase. With these observations, select from the multiple choices the species name of this isolate. Select one: a.Mycobacterium scrofulaceum b.Mycobacterium avium-intracellulare c.Mycobacterium kansasii d.Mycobacterium fortuitum #38

Mycobacterium kansasii

Illustrated in the photograph are 14 day-old colonies of a Mycobacterium species growing on Middlebrook 7H-10 agar, with development of yellow pigmentation after exposure to environmental light. From the choices listed below, select the correct presumptive identification of this photochromogenic Mycobacterium species. Select one: a.Mycobacterium chelonae b.Mycobacterium marinum c.Mycobacterium scrofulaceum d.Mycobacterium gordonae #89

Mycobacterium marinum

Illustrated in the top image are 10 day old rough, buff, gray-white colonies growing on Middlebrook 7H11 agar. These colonies are commonly recovered from expectorated or induced sputum specimens obtained from patients with signs and symptoms of pneumonia. The appearance of these colonies provide for a presumptive identification, supported by the positive yellow-pigmented niacin reaction seen in the reagent tube in the lower photograph. From these observations, select from the multiple choices the presumptive identification of this isolate. Select one: a.Mycobacterium fortuitum b.Mycobacterium kansaii c.Mycobacterium tuberculosis d.Mycobacterium gordonae #90

Mycobacterium tuberculosis

The skin infection of the foot of a farmer as illustrated in the upper photograph was caused in a farmer when walking barefoot in soil contaminated with a filariform larva. Based on the morphology of the 50 um in diameter ovum (lower image), select from the question/answer list the species that is the presumptive cause of the infection. Select one: a.Trichuris trichiura b.Enterobius vermcularis c.Necator americanus d.Ascaris lumbricoides #98

Necator americanus

Prior to receiving antibiotic therapy, a patient had a urinary tract infection with gram-negative, motile rods producing the following reactions: Indole: pos H2S (TSI): pos MR: pos VP: neg Phenylalanine deaminase: pos Urea: pos Citrate: pos Ornithine decarboxylase: neg Gelatin hydrolysis: pos Based on the reactions above, what organism is MOST likely causing the infection? Select one: a.Proteus vulgaris b.Enterobacter cloacae c.Serratia marcescens d.Klebsiella pneumonia

Proteus vulgaris

Illustrated in this photograph is a Pseudo F agar slant after inoculation and incubation with an unknown bacterial species. The bright blue-fluorescence when observed with a UV light indicates that the unknown is most likely: Select one: a.Psuedomonas putida b.Pseudomonsa stutzeri c.Burkholderia cepacia d.Comamonas acidovorans #49

Psuedomonas putida

The test used for the indentification of specific capsular serotypes of Streptococcus pneumonia is: Select one: a.Optochin b.Bile solubility c.Quellung d.Hippurate hydrolysis

Quellung

HIV is known as a retrovirus because: Select one: a.It can only attach to reticulocytes b.RNA is used as the template for DNA synthesis c.DNA is used as the template for RNA synthesis d.It can cause AIDS immediately upon entering the body.

RNA is used as the template for DNA synthesis

Illustrated in the high power photomicrograph is a large 140 um ovum as it would appear in a stool specimen preparation. The adult flukes reside in the portal veins of the large intestine where ova are discharged into the lumen and into the feces. Low grade diarrhea may be experienced. From the multiple choices select the species of fluke related to this ovum. Select one: a.Schistosoma haematobium b.Schistosoma mansoni c.Fasciola hepatica d.Schistosoma japonicum #20

Schistosoma mansoni

Which one of the following parasites migrates through the circulation (blood) before maturing in the portal venous system? Select one: a.Schistosoma mansoni b.Enterobius vermicularis c.Taenia saginata d.Trichuris trichiura

Schistosoma mansoni

The Quellung test is useful for which of the following: Select one: a.Differentiate between Staphylococcus and Streptococcus b.Serological typing of Streptococcus pneumoniae c.Isolation of various strains of Staphylococcus d.Isolation of various strains of Streptococcus

Serological typing of Streptococcus pneumoniae

In the upper bi-plate image are shown colonies growing on MacConkey, and on blood agar (right). Relatively large confluent gray white colonies are observed growing on blood agar, while smaller smooth convex colonies with a deep red pigmentation are growing on MacConkey agar. Note that the pigmentation is confined to the colonies growing on MacConkey agar that does not diffuse into the adjacent agar. In follow up to making a presumptive identification, observe that the colonies growing on the DNA'se agar in the lower image show a positive reaction with clearing of the adjacent agar, compared to the growth of a negative control growing in the streak lines to the left. Select one: a.Proteus vulgaris b. Serratia marcescens c.Providencia stuartii d. Citrobacter koseri

Serratia marcescens

The colonies growing on Middlebrook agar shown in the upper left photograph were recovered after 5 days incubation from an aspirate of a superficial skin infection. Gram stain revealed branching bacilli as seen in the lower image. These were non-acid fast. Illustrated in the upper right photograph are colonies growing on casein medium demonstrating hydrolysis. The presumptive identification is: Select one: a.Nocardia asteroides b.Nocardia brasiliensis c.Streptomyces species d.Oerskovia turbata #57

Streptomyces species

In molecular diagnostic testing, hybridization employs complementary base pair binding of a synthetic strand to DNA or RNA Select one: True False

True

The red ring at the top of the media in this tube indicates a positive indole reaction. The precursor substance in the medium from which the indole is produced is: Select one: a.Tryptophan b.p-dimethylaminobenzaldehyde c.Pyruvic acid d.Peptone #43

Tryptophan