NCA Microbiology

A urine is received in the lab for culture. If the specimen can't be plated immediately, it should be held: A. in the freezer B. in the fridge C. at room temp D. at 35 degrees in the incubator

B. in the fridge

the diagnostic stage of Strongyloides stercoralis infection is the: A. egg B. cyst C. Larva D. trophozoite

C. larva

Chlamydiae differ from viruses in that the chlamydiae: A. are true bacteria B. are obligate intracellular organisms C. produce intracellular inclusions D. are isolated in tissue culture systems

A. are true bacteria

The infective stage of this parasite consists of an egg with a thin hyaline shell, with one flattened side and usually, a fully developed larva within. The parasite is: A. Enterobius vermucilaris B. hookworm C. Ascaris lumbricoides D. Trichuris trichuria

A. enterobius vernacularis

Family characteristics of the Enterobacteriaceae include: A. fermentation of glucose B. fermentation of lactose C. production of indophenol oxidase D. failure to reduce nitrates

A. fermentation of glucose

A fungal colony grows rapidly on Sabouraud's dextrose agar as a white colony type with a dense production of aerial, blue green spores. On lactophenol cotton blue prep, swollen-lipped conidiophores bear sterigmata and conidia in chains. The most likely ID is: A. aspergillus B. Paecilomyces C. Penicillium D. Scopularopsis

A. aspergillus

A lung abscess is cultured. At 24hrs, of capneic incubation, no growth on any primary plates. Gram neg rods are seen in the thioglycolate broth. After 48 hrs: Anaerobic SBA: 3+ GNR Anaerobic laked blood agar with kanamycin-vancomycin: 3+ GNR The isolate fluoresces a brick-red color under long wave ultraviolet exposure. If allowed to incubate several more days, the colonies would be visibly: A. black pigmented B. Yellow pigmented C. orange pigmented D. Blue pigmented

A. black pigmented (prevotella)

A lysine-iron agar (LIA) slant shows a red slant over a yellow butt. This reaction indicates that the organism: A. deaminates lysine B. decarboxylates lysine C. ferments lactose D. produces H2S

A. deaminates lysine

Routine sterilization of artificial culture media by autoclaving is recommended at: A. 15 psi at 121C degrees for 15 min B. 10 psi at 121C degrees for 10 min C. 15 psi at 200F degrees for 15 min D. 10 psi at 220F decrees for 10 min

A. 15 psi at 121C for 15 min

This fungal species shown below is isolated from the blood of bone marrow transplant patients is: A. aspergillus B. penicillium C. rhizopus D. Mucor spp. E. Blastomyces

A. Aspergillus

The causative agent of Q fever is: A. Coxiella burnetii B. Rickettsia typhy (mooseri) C. Rickettsia rickettsii D. Rickettsia tsutsugamushi

A. Coxiella burnetii B- causes murine typhus, C causes rocky mountain spotted fever, and D causes scrub typhus

Twenty patients on a surgical ward develop urinary tract infections after catheterization. In each instance the isolated organism grows on SBA as a large, gray colony, and on MAC as a large, flat, pink colony. The oxidase negative, gram negative rod produces the same biotype and is resistant only to tetracycline. Additional results are as follows: PAD neg, Urease neg, H2S neg, lysine decarboxylase pos, indole pos, citrate neg The most probable organism is: A. Escherichia coli B. Enterobacter cloacae C. Enterobacter aerogenes D. Proteus vulgaris

A. E. coli (most common UTI boi)

Escherichia, Klebsiella, and Proteus species are common flora of the: A. GI tract B. respiratory tract C. Superficial skin surfaces D. urinary tract

A. GI tract

"clue cells" seen in a malodorous vaginal discharge are associated with the diagnosis of Bacterial Vaginosis; vaginal culture typically shows a predominance of: A. Gardnerella vaginalis B. Haemophilus ducreyi C. Lactobacillus spp. D. Streptococcus agalactiae

A. Gardnerella vaginalis

A patient is admitted to the hospital with symptoms of appendicitis. A stool specimen for culture reveals a gram neg bacillus that is oxidase neg, catalase pos, urease pos, and weakly fermentative. The KIA slant is orange-yellow, but the TSI slant is Y/Y. The reactions suggest: A. Yersinia enterocolitica B. Escherichia coli C. Plesiomonas shigelloides D. Pasturella multocida

A. Yersinia enterocolitica

Resipratory secretions from a patient receiving inhalation therapy reveals a non-motile gram negative coccobacilliary rod that grows on MAC as a lactose neg colony at 24hrs. Yields the following: OF glucose aerobic (acid), OF glucose anaerobic (alkaline), oxidase neg, ONPG neg, lactose alkaline, maltose alkaline, mannitol alkaline, sucrose alkaline, xylose acid Produces acid from a 10% lactose agar slant. The ID is: A. Acinetobacter baumanii B. Alcaligenes faecalis C. Moraxella asloensis D. Burkholderia cepacia

A. acinetobacter baumanii

A direct gram stain of a pelvic mass from a patient with an IUD shows numerous pus cells and branching, beaded gram pos rods. Healed, lobate colonies grow anaerobically and develop a molar tooth appearance after several days of incubation. The most probably ID is A. Actinomyces israelii B. Streptomyces spp. C. Nocardia asteroides D. Fusobacterium nucleatum

A. acintomyces israelii

ethylhydrocupreine hydrochloride (optochin) is a chemical used to differentiate: A. Catalase pos Strep from catalase neg Staph species B. Strep pneumo from alpha hemolytic strep C. Enterobacteriaceae from non-enterobacteriaceae D. group D enterococci from group D- NON enterococci

B. Strep pneumo from alpha hemolytic strep

A specimen for viral culture is collected on a friday and must be held for processing until the next day. In general, the optimal temperature for holding this specimens is: A. 35C B. 4C C.-20C D.-70C

B. 4C

A potentially pathogenic yeast that is normal flora in the oropharyngeal cavity and may produce thrush is: A. Trichosporon beiglii B. Candida albicans C. Cryptococcus neoformans D. Geotrichum

B. Candida albicans

Which of the following pairings of yeast species with identifying characteristics are correct? A. Cryptococcus neoformans; urease neg, capsulated B. Candida albicans; germ tube pos, chlamydoconidia producer C. Torulopsis glabrata: urease pos, arthroconidia producer D. Geotrichum spp.; hyphae-blastoconidia pos, arthroconidia producer

B. Candida albicans

Neisseria spp. can be identified and differentiated by: A. Bile esculin hydrolysis B. carbohydrate utilization C. nitrate test D. oxidase test

B. Carbohydrate utilization

The X and V factors required for growth of Haemophilus influenzae are contained in: A. Brain/heart infusion broth B. chocolate agar C. SBA D. Thioglycolate broth

B. Chocolate agar

In an iodine prep of feces, an amoebic cyst appears to have a single nucleus with a large karyosome and chromatin bodies don not appear along the nuclear membrane. A large glycogen mass that stains reddish brown occupies the cytoplasm. The most probable specimen: A. Entamoeba histolytica B. Iodamoeba butschlii C. Entamoeba coli D. Entamoeba hartmanni

B. Iodamoeba butschlii

A mucoid, lactose positive colony type on MacConkey agar that is indole negative and citrate positive and non-motile is: A. Escherichia coli B. Klebsiella pneumoniae C. Enterobacter cloaceae D. Enterobacter aerogenes

B. Klebsiella pneumonia

A physician inquires about repeated sputum specimens, negative on routine bacterial culture, that are reported to contain only normal oropharyngeal flora on routine bacterial culture. The patient is a 67yr old man who smokes 15-20 cigarettes a day and has persistent cough, malaise, and a fever of 102-105. Empiric antimicrobial therapy hasn't been effective; the cough and fever persist. The most recent gram stain shows 3+ PMNs, mucus, and rare epithelial cells. A likely ID is: A. Haemophilus influenzae B. Legionella pneumophila C. Pseudomonas aeuriginosa D. Streptococcus pneumoniae

B. Legionella - hard to find

To check for pos and neg reactions, select the appropriate set of QC organisms for the following tests: Bile esculin, bacitracin, 6.5% NaCl tolerance, Hippurate hydrolysis A. Strep pyogenes, Viridans strep, enterococci B. S. pyogenes, strep agalactiae, enterococci C. Staph aureus, S. pyogenes, enterococci D. S. agalactiae, Viridans strep, enterococcus

B. S. pyogenes (neg for bile esculin, NaCl, and Hippurate, positive for bacitracin), strep agalactiae (pos for hippurate, neg for bacitracin) enterococci (pos for bile esculin and 6.5% NaCl)

Which of the following depictions does NOT pertain to Pasturella multocida? A. Gram neg coccoid bacillus B. Growth on MAC C. Nonhemolytic on SBA D. oxidase positive

B. growth on MAC

In the Kirby-Bauer agar disk diffusion susceptibility test, a steady decrease in zone diameter of the methicillin disks obtained with the control organism Staph aureus, ATCC 25923, may be due to the fact that the: A. S. aureus control strain is too old B. methicillin disks were not stored frozen C. pH of the agar is less than 7.2 D. Mueller-Hinton agar is too thick

B. methicillin disks were not stored frozen

Which result is NOT consistent with the ID of Mycobacterium fortuitum? A. Arysulfatase positive B. Nitrate reduction negative C. Growth on MAC D. Growth in 5% NaCl

B. nitrate reduction negative

Which of the following is characteristic of Dientamoeba fragilis? A. easily recognized by its rapid, jerky motility B. no known cyst stage, troph shaped like an amoeba C. two to four nuclei have a small pin dot karyosome D. the size is smaller than E. nana

B. no known cyst stage, troph shaped like an amoeba

In interpreting a minimal inhibitory concentration (MIC) by the macro-broth-dilution method, you determine the first test tube that shows visible turbidity has a final dilution factor of 1:32. since twofold serial dilutions are made from the working stock of 0.256mg/mL, the MIC for this isolate is: A. 4ug/mL B. 8ug/mL C. 16 ug/mL D. 32 ug/mL

C. 16 ug/mL MIC-the last negative (no growth) end point is 1:16. Divide the stock (256) by the dilution factor of 16.

To eliminate the antibacterial properties of blood and simultaneously introduce an adequate volume of blood for recovery of microorganisms from septicemia, the recommended blood-to-broth ratio in the blood culture bottle is: A. 1:2 B. 2:1 C. 1:10 D. 10:1

C. 1:10

A gram negative rod not biochemically compatible with the genus Salmonella fails to agglutinate in the polyvalent somatic antisera for Salmonella serotyping. What is the next step in the definitive identification of this organism? A. report the organism as a Salmonella polyvalent O-pos species and sent the isolate elsewhere for additional ID B. Wash a suspension of the isolate in saline and retest it in the antisera C. Boil a saline suspension of the organism for 15 min, cool, and retype in antisera D. Retest the isolate using the individual somatic antisera from each serogroup, A - E

C. Boil a saline suspension for 15 min, cool, and retest

The pair of organisms that would provide a good positive and negative control for PEA blood agar is: A. pseudomonas aeuriginosa and E. coli B. Haemophilus influenzae and Strep pyogenes C. Enterococcus and E. coli D. Staph aureus and Strep pyogenes

C. Enterococcus and E. coli

A 43 yr old female patient complains of a very sore throat. The swab that is submitted for routine culture grows a variety of diptheroidic, alpha, beta, and non-hemolytic streptococci, staphylococci, and Neisseria. The next step is to: A. report it as normal flora B. ask for a repeat collection to get a better specimen C. identify the beta-hemolytic colonies D. Identify the Neisseria species

C. Identify the beta-hemolytic colonies

Isolation of Campylobacter jejuni from a patient with gastroenteritis is optimized by: A. incubation at 35-37 degrees B. Selective enrichment in selenite broth C. a microaerophillic environment D. an anaerobic environment w/o CO2

C. a microaerophillic environment

Physical examination of a 20yr old man seen in the ED reveals nuchal rigidity and a temp of 102 degrees. Gram stain of the CSF shows numerous WBCs and a few gram neg diplococci. The isolate grows on SBA and is oxidase positive. Acid production: glucose (acid), lactose (acid), maltose (acid), sucrose (acid). The most appropriate action to take is: A. ID the organism as meningococcus and report it B. ID the organism as Moraxella and set up additional tests to determine the species C. Gram stain and subculture the CTA sugars to check them for purity D. perform MICs as a confirmation of the ID

C. stain and subculture the CTA sugars to check for purity - meningitis classic case - only exclusive to 3 sugars not all.

A sputum specimen is submitted to the lab accompanied by a request for an AFB culture. All of the following are standard protocol for processing EXCEPT: A. use of a refrigerated centrifuge with bucket covers and safety comes for high-speed concentration B. use of both liquid and solid media for setup of AFB culture C. use of concentrated potassium hydroxide for decontamination D. Use of a laminar flow biological safety cabinet for processing

C. use of a concentrated potassium hydroxide for decontamination

CSF fluid from a 24 yr old man reveals a high number of mononuclear cells and a negative routine culture for bacteria. Spinal fluid, glucose and protein values are normal. In addition, the patient has vesicular genital lesions. The most likely agent is: A. Neisseria meningitidis B. Strep pneumo C. Chlamydia trachomatis D. herpes simplex virus

D. Herpes simplex virus

A pustule drainage submitted for culture is plated onto primary media. After an 18-h incubation, the sheep-blood agar plate reveals a predominance of beta-hemolytic, white, porcelain like colonies. Gram stain shows a gram positive cocci that test catalase positive. The most appropriate test for additional identification of the isolate is: A. bacitracin B. bile esculin C. bile solubility D. coagulase

D. Coagulase

Standardized testing conditions for the K-B agar disk diffusion antimicrobial susceptibility test include all of the following EXCEPT: A. use of Mueller-Hinton media B. Standard inoculum size C. Incubation at 35C D. incubation at 8-10% CO2

D. Incubation at 8-10% CO2

A 15 yr old girl was admitted with severe headaches and confusion. An exam of her spinal fluid revealed many small motile amoeba. The girl was visiting friends in Georgia and had been swimming and diving in a freshwater pond. The most likely specimen is: A. Entamoeba histolytica B. Endolimax nana C. Iodamoeba butschlii D. Naegleria fowleri

D. Naegleria fowleri

Which of the following organisms would give the appropriate pos and neg reactions for QC as listed? A. gram stain - E. Coli (pos), Neisseria meningitidis (neg) B. Indole - E. Coli (pos), Proteus vulgaris (neg) C. Catalase - S. aureus (pos), S. epidermitidis (neg) D. Oxidase - Pseudomonas(pos), E. Coli (neg)

D. Oxidase - pseudo pos and E. coli neg

A thick film has been prepared from a patient suspected of having malaria. It is stained with Wright's stain. Inclusions seen in the patients erythrocytes are described as blue disks with red nuclei. The infected erythrocytes are generally enlarged and some of them have granules of brown pigment. Many appear to have more than 15 nuclear masses in a single cell. Which Plasmodium am I? A. Plasmodium falciparum B. Plasmodium malariae C. Plasmodium ovale D. Plasmodium vivax

D. Plasmodium vivax - likes the young (larger) cells, signet rings, schuffners dots (brown)

A gram neg rod is isolated from a patient with 2nd and 3rd degree burns. The isolate produces a bluish green pigment and a characteristic fruity odor. Other characteristic observations are: K/K, motility pos, oxidase pos The most probable isolate is: A. Acinetobacter B. Alcaligenes C. Moraxella D. Pseudomonas

D. Pseudomonas

From the dimorphic fungi and major identifying morphologic features listed, select the species whose major characteristics are not described correctly: A. Blastomyces dertmatitidis; thick walled yeast cells with single, broad based buds at 37 degrees B. Coccidiodes immitis; barrel shaped arthrospores at 25 degrees C. Histoplasma capsulatum; spherical, tuberculated macroaleuriospicules at 25 degrees D. Sporothrix schenkii; thick walled yeast cells with with multiple buds at 25 degrees

D. Sporothrix shenkii - branched slender conidiophores with small conidia arranged in flowerettes or in a sleeve arrangement

Safety precautions designed to minimize lab acquired infections when working with M. tuberculosis in a clinical laboratory would prevent spreading of these organisms by: A. aerosol production B. ingestion C. superficial contact D. contact with fomites

A. aerosol production

To differentiate between a coagulase-neg staph species and a micrococcus species, which of the following can be used? A. Furazolidone (100ug/disk) susceptibility B. Catalase C. Novobiocin susceptibility D. Urease

A. furazolidone susceptibility

On thiosulfate-citrate-bile-salts-sucrose (TCBS) agar, colonies of Vibrio cholerae appear: A. yellow B. colorless C. olive green D. black

A. yellow

Both blood and urine cultures are pos for an oxidase neg, gram neg rod that is colorless on MAC. Biochemical reactions are included: TSI A/A, gas H2S neg, indole neg, citrate pos, motility pos, DNase pos, ornithine decarboxylase pos, lysine pos The opportunistic pathogen that shows these reactions is: A. Escherichia coli B. Serratia marcescens C. Enterobacter aerogenes D. Klebsiella pneumoniae

B. Serratia marcenscens - because of the DNase pos

Falsely decreased zone diameters on a Kirby Bauer agar disk diffusion test would most likely result from: A. an inoculum that is less turbid that a 0.5 McFarland standard B. use of disks with a higher-than recommended concentration of anti-microbial C.a 2-h delay in placing the antimicrobial disk on the second plate D. a 2-h delay in incubating the plates after the disks have been applied

C. a 2-h delay in placing the disks on the second plate

The function of 10% potassium hydroxide in the direct examination of skin, hair and nail scrapings is to: A. preserve fungal elements B. Kill contaminating bacteria C. clear and dissolve debris D. Fix prep for subsequent staining

C. clear and dissolve debris

The color of a nonacid-fast bacillus following the acid-alcohol step and before counterstaining in the acid-fast stain procedure is: A. blue B. red C. colorless D. Green

C. colorless

The direct iodine prep is best used to detect protozoan: A. eggs B. Trophs C. cysts D. Larvae

C. cysts

In the N-acetyl-L-cystine alkali method of processing sputum specimens for mycobacterial culture, the N-acetyl-L-cysteine serves as a: A. buffer B. decontaminant C. digestant D. pH stabilizer

C. digestant

Two organisms that are thought to act synergistically to produce an ulcerative infection of the gums, commonly called trench mouth are called: A. Strep and Staph B. yeast and fusiform C. fusiform and treponemes D. spirochetes and treponemes

C. fusiform and treponemes (Borriella and Fusobacterium)

You suspect a yeast isolated from a urine sample of a 25 yr old female patient is Candida albicans. Which of the following is the test when positive will ID your isolate? A. hair penetration test B. Urease test C. Germ tube D. Nitrate reduction E. Arthroconidia production on corn meal agar

C. germ tube

Which of the following statements regarding Simmon's citrate agar is INCORRECT? A. blue color is an alkaline reactino B. Citrate is the only source of carbon in the media C. glucose is the carbohydrate in the media D. Growth on the slant is interpreted as a pos reaction

C. glucose is the carbohydrate in the media

A procedure that directly determines beta-lactamase production by a microorganism is based on detection of a: A. zone of susceptibility around and ampicillin disk B. zone of inhibition around an oxacillin disk C. increased acidity due to the release of penicilloic acid D. Increase in pH due to the reduction of iodine

C. increase in acidity due to the release of penicilloic acid

In a broth dilution method of antimicrobial susceptibility testing, the tube with the lowest concentration of antimicrobial in which there is no visible growth is the minimal: A. antimicrobial concentration B. bactericidal concentration C. inhibitory concentration D. lethal concentration

C. inhibitory concentration (MIC)

Special handling or methods are required when blood cultures are requested on a patient to recover the following organisms EXCEPT: A. nutritionally deficient strep spp. B. Candida albicans C. Mycobacterium tuberculosis D. Salmonella serotype typhi

D. Salmonella serotype typhi - comes up quick on its own

On a sheep blood agar plate, Haemophilus influenzae satellites around colonies of: A. diphtheroids B. Streptococcus pyogenes C. Haemophilus parainfluenzae D. Staphylococcus aureus

D. Staph aureus

The metabolism of glucose by the Klebsiella-Enterobacter-Serratia group is as follows: Glucose->2,3 butanediol +2CO2 +H2 The reaction is the basis for the: A. glucose oxidation reaction B. Methyl red test C. Oxidative-fermentation (O-F) glucose test D. Voges-Proskauer Test

D. VP test - for klebsiella family

The reagent used to detect a positive phenylalanine-deaminase reaction is: A. sulfanilic acid and alpha-napthylamine B. p-aminodimethylbenzaldehyde C. alpha-naphthol and potassium hydroxide D. ferric chloride

D. ferric chloride

All of the following describe the orthonitrophenyl galactoside (ONPG) test EXCEPT: A. it detects the presence or absence of the enzymes beta-galactosidase in an organism B. It is positive for organisms that produce both beta galactosidase and galactoside permease C.It is positive for isolates that are capable of fermenting lactose but lack the permease D. it detects the decarboxylation of ONPG to ornithine and galactose

D. it detects the decarboxylation of ONPG to ornithine and galactose

Parasites that are detected by direct visualization in a peripheral blood smear are: A. Ascaris B. Entamoeba C. Giardia D. Plasmodium

D. plasmodium

Which of the following characteristics is NOT consistent with Streptococcus pneumoniae? A. Alpha hemolysis on SBA B. bile solubility positive C. Gram pos, oval shaped cocci in pairs D. positive catalase test

D. positive catalase test

A nasopharyngeal culture grows a predominance of a beta-hemolytic colony type on sheeps blood at 18 hrs. The isolate is susceptible to a 0.04 unit of bacitracin. The most likely identification is beta-hemolytic streptococcus, A. group A B. group B C. group D D. Not group A,B, or D

A. Group A Strep (pyogenes)

MAC agar is used for the isolation of members of the family Enterobacteriaceae because the medium is: A. inhibitory and differential B. differential and enriched C. enriched and selective D. selective and supplemented

A. inhibitory and differential

After 48 h of incubation on an aerobic SBA, Clostridium perfringens appears as a: A. large, flat colony with a double zone of hemolysis B. white, butyrous, non-hemolytic colony with a glistening surface C. gray, mucoid colonies with a zone of alpha hemolysis D. colony with a pearl like surface and a single zone of beta hemolysis

A. large, flat colony with a double zone of hemolysis

Which of the following media has a high protein content and requires sterilization by inspissation(moist heat method-coag/evaporation)? A. lowenstein jensen egg B. SBA C. Thioglycolate D. Christensen's urease

A. lowenstein jensen egg

The intestinal parasite shown below (GIARDIA) which is recovered from steatorrheic stool, will produce which of the following: A. malabsorption syndrome B. iron deficiency anemia C. intestinal infection D. vit B12 deficiency

A. malabsorption syndrome

Which of the following characteristics is NOT used to characterize Staphylococcus aureus? A. "pitting" on sheeps blood agar B. fermentation of mannitol C. Positive catalase test D. Positive coagulase test

A. pitting on sheeps blood

Fusarium species have on occasion been associated with corneal ulcers, ulcerated skin conditions, and mycetoma. Typical macro morphologic and micro morphologic features are: A. rapid growers that usually produce a lavender pigment and crescent shaped, septate macroconidia B. rapid growers that darken with age and produce aseptate hyphae with rhizoids C. slow growers that are velvety and light tan with a salmon colored reverse, and seldom produce macroconidia D. Slow growers that are grey brown and produce multicellular macroconicia with both transverse and longitudinal septa

A. rapid grower that produce a lavender pigment and crescent shaped septate macroconidia B is Zygomycetes, C is Microsporum, D is Alternaria

An 8 yr old child presents with tine capitis thought to be caused by Microsporum canis. Characteristics of this fungi include: A. spindle-shaped, thick walled macroconidia with an asymmetric terminal knob B. demonstration of endothrix invasion of hair C. salmon colored reverse of colony D. production of abundant peg shaped microconidia on Saburaud's dextrose agar

A. spindle shaped thick walled macrocondia with an asymmetric terminal knob

Bacteria that are glucose oxidizers in Hugh-Leifson (H-L) media produce an alkaline/no change reaction on KIA because: A. these organisms produce insufficient amounts of acid to be detected in KIA B. The lactose component in KIA inhibits glucose oxidation in this media C. the concentration of glucose in KIA is higher than in the O-F glucose media D. KIA detects only fermentation of lactose

A. these organisms produce insufficient amounts of acid to be detected in KIA

A lumbar puncture is performed on an 82 yr old woman who is receiving immunosuppressive therapy. The gram stain of the CSF reveals gram pos rods and numerous WBCs. At 18 hrs, small translucent colonies with a narrow zone of beta hemolysis grow on SBA. The isolate produces catalase. ID of this could be done by demonstration of: A. tumbling motility B. metachromatic granulation C. hippurate hydrolysis D. H2S production on TSI slant

A. tumbling motility (its Listeria)

Purulent material is obtained from a carbuncle and submitted for bacterial culture. The direct smear reveals many gram pos cocci and WBCs. The culture shows growth in the primary broth and on the SBA plate but not on MAC. The colonies are butyrous, white and b-hemolytic. catalase positive, and modified oxidase negative. coag neg, tube coag pos. What am I? A. Micrococcus sp. B. Staph aureus C. Staph epidermidis D. Staph saprophyticus

B. Staph aureus

This adult disease results from a neurotoxin that is ingested and causes the symptoms of neuromuscular flacid paralysis. The agent that produces the toxin is: A. Bacillus cerus B. Clostridium botulinum C. clostridium tetani D. Staph aureus

B. clostridium botulinum

A 20 yr old man with urethritis who had been treated with penicillin returns to the outpatient clinic the following week. A possible cause of his symptoms is Chlamydia trachomatis, which may be confirmed by: A. inoculating the specimen onto selective media B. Demonstrating inclusion bodies in the cell culture C. performing a direct Gram stain for gram neg rods D. Performing a blind passage of cells

B. demonstrating inclusion bodies in the cell culture

Two siblings arrive at the ER. Both had antecedent sore throats about 2-3 weeks earlier that grew B-hemolytic streptococci; now they present with different clinical symptoms. the brother displays edema and hypertension and RBC casts are seen in the urine. The sister complains of fever and joins pains and has carditis. The diseases that these siblings have are most likely: A. erysipelas and glomerulonephritis B. glomerulonephritis and rheumatic fever C. rheumatic fever and scarlet fever D. scarlet fever and erysipelas

B. glomerulonephritis and rheumatic fever

A gram neg coccobacillus organism that is isolated from synovial fluid on CHOC resembles either a Moraxella or Neisseria gonnorhoeae. The single best test to differentiate is: A. Beta hemolysis B. glucose degradation C. motility D. oxidase production

B. glucose degradation

In a synergy study, when drug A, drug B, and drug A+B act singly and in combination on a single population of growing bacteria in vitro, the type of action signified is: A. antagonism B. indifference C. synergism D. indeterminate

B. indifference

Which of the following is unique to Pseudomonas? A. Growth at 30C B.production of pyocyanin, a blue or green pigment C. beta hemolytic on both sheep and horse blood agar D. oxidation of O-F glucose media

B. production of pyocyanin

When acetone-alcohol is inadvertently omitted from the gram stain procedure, strep and Neisseria will be stained, respectively: A. purple and red B. purple and purple C. red and red D. red and purple

B. purple and purple

A stool culture from an adult appears to have two lactose neg colonies on Hektoen(HE) and Xylose-lysine-deoxycholate (XLD) agar. One colony type remains the original color of each media and the other has black centers. IOS1 - h2s neg, urease neg, no gas IOS2 - H2S pos, urease pos, gas Based on this, the next important step is to? A. set up confirmatory test for Campylobacter sp. B. set up shigella serotyping C. set up salmonella serotyping D. report the culture as negative

B. set up shigella serotyping ISO1- shigella ISO2- proteus

A recently FDA approved direct antigen test to detect group A strep in throat samples shows a 90% sensitivity and 98% specificity. In a population with a prevalence of 5%, the calculated pos predictive value for this test is 70.3%. This means that: A. the test is at least 70% accurate B. theres a 30% chance an individual may not have the disease C. 30% of the population tested will give a false negative result D. the test is positive in 70% of the population E.70% of the population tested will give a false positive

B. theres a 30% chance an individual may not have the disease

A diary farmer who has an intermittent fever, progressive weakness, and night sweats is suspected of having undulant fever. Blood cultures from this patient yield an organism that shows the following: requires an atmosphere of 10% CO2, urease pos, grows in thionine dye but not in the presence of fuchsin. Which am I? A: Bacillus anthracis B. Brucella suis C. Brucella abortus D. Brucella melitensis

C. Brucella abortus (cows abortions)

A small gram positive rod that carries neonatal meningitis and septicemia is: A. escherichia coli B. Corynebacterium diphtheriae C. Listeria monocytogenes D. Streptococcus agalactiae

C. Listeria monocytogenes

An AFB has been isolated from the sputum of a patient suspected to have a mycobacterial pulmonary disease. The organism is a slow growing isolate that produces cream to tan colored colonies when grown in the dark, and turns bright yellow upon exposure to the light. Who am I? A. Mycobacterium avium B.Mycobacterium chelonei C. Mycobacterium kansasii D. Mycobacterium scrofulaceum

C. Mycobacterium kansasii

The specimen of choice for the isolation of Bordetella pertussis from a suspected case of whooping cough is: A. blood B. CSF C. nasopharyngeal swab D. throat swab

C. Nasopharyngeal swab

Trematodes that mature in the lung and produce eggs that appear in the sputum or stool are probably: A. Fasciolopsis buski B. Schistosoma japonicum C. Paragonimus westermani D. Clonorchis sinensis

C. Paragonimus westermani

Which of the following specimens is acceptable for the evaluation of clinically important anaerobes? A. feces B. sputum C. peritoneal fluid D. Superficial wound

C. Peritoneal fluid

A discharge from an infected ear grows a colorless colony type on MAC that swarms on SBA. This oxidase negative, gram neg rod gives the following reactions: PAD pos, H2S pos, urease pos, lysine neg, ornithine pos, indole neg, citrate pos The organism described is: A. Citrobacter freundii B. Morganella morganii C. Proteus mirabilis D. Proteus vulgaris

C. Proteus mirabilis

A saprobic yeast that inhabits airborne dust, skin and mucosa grows rapidly and produces orange to red color. This isolate most likely belongs to the genus: A. Cryptococcus B. Geotrichum C. Rhodotorula D. Saccharomyces

C. Rhodotorula

An early morning, clean catch, midstream urine specimen yields the following: Yellow, cloudy, glucose neg, nitrite pos, blood neg, protein +1, ketones neg, bili neg, 15-25 WBC casts, many bacteria This indicates: A. the bacteria present are the result of collection into a non sterile container and correlate to a probable original count of less than 10^4 CFU/mL B. the bacteria present are the result of a delay in several hours in processing and correlate to a probable original count of less than 10^4 C. significant UTI that correlates to a probable original count of greater than 10^5 CFU should be suspected D. nephrotic syndrome should be considered, and the bacteria are merely coincidental

C. Significant UTI that correlates to a probable original count of greater than 10^5

A stool specimen is submitted for culture from a patient with gastroenteritis, nausea, and vomitting. A gram neg rod grows on TCBS as a large green colony type. Additional screening characteristics include: H2s neg, oxidase pos, catalase pos, nitrate pos, lysine pos, broth with 0% NaCl no growth, broth with 3% NaCl growth. The most probable ID is: A. Aeromonas hydrophila B. Shigella flexneri C. Vibrio parahaemolyticus D. Yersinia enterocolitica

C. Vibrio - the agar gives it away

Nocardia species that cause nocardiosis often are: A. obligate anaerobes B. Gram variable C. partially acid fast D. Spore forming rods

C. partially acid fast

In an overcrowded poverty-stricken central core of a US-Mexico border town, a 15 month old baby girl is admitted to the ED with fever, respiratory coughing spells that make the child gasp for air, and a cyanotic appearance. lab findings show lymphs. the probable diagnosis is: A. diphtheria B. epiglottitis C. pertussis D. trench mouth

C. pertussis