Microbiology BOC

Which of the following groups of specimens would be acceptable for anaerobic culture? A. vaginal, eye B. ear, leg tissue C. pleural fluid, brain abscess D. urine, sputum

Correct Answer: C

Which of the following methods is inadequate for the detection of vancomycin-intermediate S. aureus? A. broth macrodilution B. agar dilution C. gradient diffusion D. disk diffusion

Correct Answer: D

Which of the following test is used to monitor bactericidal activity during antimicrobic therapy in cases of endocarditis? A. Elek B. tolerance C. Sherris synergis D. Schlichter

Correct Answer: D

Appropriate culture requirements for a specimen from a patient suspected of having tularemia include: A. a media with cysteine such as buffered charcoal yeast extract agar B. colistin nalidix acid agar C. Mueller-Hinton agar with 5% sheep blood agar D. Regan-Lowe media

Correct Answer: A

The Gram stain of drainage form a pulmonary sinus tract shows many WBCs and 3_ branching gram -positive bacilli. Colonies grow only on anaerobic media after 3 days incubation. They are yellow-tan and have a molar tooth appearance. The most likely genus is: A. Actinomyces B. Bacteroides C. Fusobacterium D. Nocardia

Correct Answer: A

The best medium for culture of Bordetella pertussis is: A. Regan-Lowe agar B. cystine blood agar C. Martin Lewis agar D. Ashdown agar

Correct Answer: A

The causative agent of cysticercosis is: A. Taenia solium B. Taenia saginata C. ascaris lumbricoides D. Trichuris trichiura

Correct Answer: A

The expected colony count in a suprapubic urine from a healthy individual is: A. 0 CFU/mL B. 100 CFU/mL C. 1,000 CFU/mL D. 100,000 CFU/mL

Correct Answer: A

The lowest concentration of antibiotic that inhibit growth of a test organism is the: A. minimum inhibitory concentration B. serum inhibitory concentration C. minimum bactericidal titer D. maximum inhibitory titer

Correct Answer: A

The major features by which molds are routinely identified are: A. macroscopic characteristics and microscopic morphology B. biochemical reactions and microscopic morphology C. macroscopic characteristics and selective media D. specialized sexual reproductive structures

Correct Answer: A

The most meaningful laboratory procedure in confirming the diagnosis of clinical botulism is: A. demostration of toxin in the patient's serum B. recovery of clostridium botulinum from suspected food C. recovery of Clostridium botulinum form the patient's stool D. Gram stain of suspected food for gram-positive, sporulating bacilli

Correct Answer: A

The preferred carbon source for mycobateria is: A. glycerol B. glucose C. fatty acids D. casein hydrolysate

Correct Answer: A

The recovery of some Cryptococcus species may e compromised if the isolation media contains: A. cycloheximide B. gentamicin C. chloramphenicol D. penicillin

Correct Answer: A

The reverse CAMP test, lecthinase production, double zone hemolysis, and Gram stain morphology are all useful criteria in the identification of: A. Clostridium perfringens B. Streptococcus agalactiae C. Propionibacterium acnes D. Bacillus anthracis

Correct Answer: A

The scolex of Taenia saginata has: A. 4 suckers B. no suckers and 14 hooklets C. 24 hooklets D. 26-28 sucking discs

Correct Answer: A

The steam autoclave method of sterilization: A. uses 15 lbs of pressure for 15 minutes B. utilizes dry heat for 20 minutes C. produces a maximum temperature of 100C D. requires a source of ethylene oxide

Correct Answer: A

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

Correct Answer: B

A 24-year-old man presents with pain on urination and urethral discharge. A Gram stain of the discharge is seen in the image: See BOC pg 292 Pic 1 What is the most likely identification of this organism? A. Acinetobacter baumanni B. Neisseria gonorrhoeae C. Haemophilus ducreyi D. Escherichia coli

Correct Answer: B

A 27-year-old scuba diver has an abrasion on his left thigh. A culture of this wound grew an acid-fast organism at 30C. This isolate most likely is: A. Mycobacterium chelonae B. Mycobacterium marinum C. Mycobacterium tuberculosis D. Mycobacterium xenopi

Correct Answer: B

A 29-year-old man is seen for recurrence of a purulent urethral discharge 10 days after the successful treatment of culture proven gonorrhea. The most likely etiology of his urethritis is: A. Mycoplasma hominis B. Chlamydia trachomatis C. Trichomonas vaginalis D. Neisseria gonorrhoeae

Correct Answer: B

A 4-year-old boy is admitted to the hospital with suspected meningitis. he has not had most of the childhood vaccines. The suspected pathogen is: A. Listeria monocytogenes B. Haemophilus influenzae C. Streptococcus agalactiae D. Neisseria meningitidis

Correct Answer: B

A 73-year-old man diagnosed as having pneumococcal meningitis is not responding to his penicillin therapy. Which of the following tests should be performed on the isolate to best determine this organism's susceptibility to penicillin? A. beta-lactamse B. oxacillin disk diffusion C. penicillin disk diffusion D. Schlichter test

Correct Answer: B

A Camplobacter species isolated form a stool culture gives the following biochemical reactions: -nalidixic acid: susceptible -cephalothin: resistant -hippurate hydrolysis: positive -oxidase: positive -catalase: positive This biochemical profile is consistent with: A. Campylobacter fetus B. Campylobacter jejuni C. Campylobacter coli D. Campylobacter laridis

Correct Answer: B

An aspirate of a deep wound was plated on blood agar plate aerobically and anaerobically. At 24 hours there was growth on the anearobic plate only. The next step in the evaluation of this culture is to: A. reincubate for another 24 hours B. begin organism identification C. issue the final report D. set up a Bauer-Kirby sensitivity

Correct Answer: B

An aspirated specimen of purulent material was obtained from a brain abscess. After 24 hours incubation, pinpoint colonies grew on sheep blood and small, yellowish colonies grew on chocolate. Gram stain of the organism showed gram-negative cocci. Results of carbohydrate degradation studies were as follows: -glucose: acid -maltose: acid -sucrose: acid -lactose: negative Additional testing revealed that the organism was oxidase positive and beta-galactosidase negative. The organism is most likely Neisseria: A. meningitidis B. sicca C. lactamica D. gonorrhoeae

Correct Answer: B

An autopsy performed on an 8-year-old revealed Waterhouse-Friderichsen syndrome. Blood and throat cultures taken just prior to death were positive for which organism? A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Haemophilus influenzae D. Klebsiella pneumoniae

Correct Answer: B

An organism from a peritoneal abscess is isolated on kanamycin-vancomycin laked blood agar and grows black colonies on BBE agar. It is nonpigmented, catalase positive, and indole negative. The genus of this organism is: A. Acidominococcus B. Bacteroides C. Porphyromonas D. Prevotella

Correct Answer: B

An organism previously thought to be nonpathogenic, Moraxella catarrhalis, s now known to be associated with opportunistic respiratory infection and nosocomial transmission. Characteristic identification criteria include; A. oxidase negative B. carbohydrates negative (assacharolytic) C. betalactamase negative D. gram-negative bacilli

Correct Answer: B

An unusual number of Mcobacterium gordonae have been isolated. The most likely source is: A. an outbreak of infections due to Mycobacterium gordonae B. contamination by water organisms C. contamination of commercial Lowenstein-Jensen tubes D. contamination of the specimen collection containers

Correct Answer: B

Assuming the agent isolated from a patient's spinal fluid produces a positive oxidase test, the most likely diagnosis is: A. tuberculous meningitis B. meningococcal meningitis C. viral meningitis D. pneumococcal meningitis

Correct Answer: B

At the present time Clostridium difficile toxin can be detected by: A. fluorescent staining B. EIA C. latex agglutination D. high-pressure liquid chromatography

Correct Answer: B

Blood cultures from a case of suspected leptospiremia should be drawn: A. between 10 PM and 2 AM B. in the first 7-10 days of infection C. during febrile periods, late in the course of the disease D. after the first 10 days of illness

Correct Answer: B

Characterictically, enterococci are: A. unable to grow in 6.5% NaCl B. relatively resistant to penicillin C. sodium hippurate positive D. bile esculin negative

Correct Answer: B

Characteristics of the genus Capnocytophaga include: A. grows in ambient air B. colonies are large and spreading after 2-4 days C. considered "nonfermenter" D. gram-positive bacillus

Correct Answer: B

Children who have infections with beta-hemolytic streptococci can develop: A. acute pyelonephritis B. acute glomerulonephritis C. chronic glomerulonephritis D. nephrosis

Correct Answer: B

Coagglutination is associated with: A. Chlamydia trachomatis B. Neisseria gonorrhoeae C. Streptococcus pneumoniae D. Klebsiella pneumoniae

Correct Answer: B

Colds and other acute respiratory diseases are most often associated with: A. Epstein-Barr virus B. adenovirus C. coxsackie B D. reovirus

Correct Answer: B

Encephalitis is most commonly associated with which of the following viruses? A. Epstein-Barr virus B. herpes simplex C. coxsackie B D. varicella zoster

Correct Answer: B

In a suspected case of Hansen disease (leprosy), a presumptive diagnosis is established by: A. isolation of organism on Lowenstein-Jensen medium B. detection of weakly acid-fast bacilli in infected tissue C. isolation of organism in a cell culture D. detection of niacin production by the isolated bacterium

Correct Answer: B

In disk diffusion susceptibility testing, as an antimicrocial agent diffuses away from the disk, the concentration of antibiotic is: A. increased B. decreased C. unchanged D. inoculum dependent

Correct Answer: B

In the disk diffusion method of determining antibiotic susceptibility, the size of the inhibition zone used to indicate susceptibility has been determined by: A. testing 30 stains of 1 genus of bacteria B. correlating the zone size with minimum inhibitory concentrations C. correlating the zone with minimum bactericidal concentrations D. correlating the zone with the antibiotic content of the disk

Correct Answer: B

Infection of the urinary tract is most frequently associated with: A. Staphylococcus aureus B. Escherichia coli C. Enterococcus faecalis D. Serratia marcescens

Correct Answer: B

Photochromgens produce pigment when: A. kept in the at 22C B. exposed to light for 1 hour C. grown in the presence of CO2 D. incubated with x-ray film

Correct Answer: B

Production of beta-lactamase is inducible in which of the following: A. Haemophilus influenzae B. Staphylococcus aureus C. Corynebacterium diphtheriae D. Streptococcus pyogenes

Correct Answer: B

Psittacosis is transmissible to man via contact with: A. insects B. birds C. cattle D. dogs

Correct Answer: B

Quality control testing of CHROMagar Candida medium shows weakly colored colonies after incubation at 25C, ambient atmosphere for 48 hours. The technologist should: A. repeat the quality control tests to verify results B. repeat the quality control tests but incubate at 35C C. repeat the quality control tests using new subcultures of the quality control organisms D. discard this lot of CHROM and repeat the quality control tests on a new lot number

Correct Answer: B

Refer to the following image: See BOC pg 339 Pic 1 Upon finding the above in a fecal concentrate, the technologist should: A. telephone the report of this pathogen to the physician immediately B. review the fecal concentration carefully for the presence of other microorganisms that may be pathogenic C. look for motile trophozoites D. request a new specimen because of the presence of excessive pollen grains

Correct Answer: B

Refer to the following image: See BOC pg 340 Pic 2 The organism depicted is a(n): A. amoeba B. flagellate C. filaria D. sporozoan

Correct Answer: B

Shigella species characteristically are: A. urease positive B. nonmotile C. oxidase positive D. lactose fermenters

Correct Answer: B

The ONPG test allows organisms to be classified as a lactose fermenter by testing for which of the following? A. permease B. beta-galactosidase C. beta-lactamase D. phosphatase

Correct Answer: B

The advantage of thick blood smears for malarial parasites is to: A. improve staining of the organisms B. improve detection of the organism C. remove RBC artifacts D. remove platelets

Correct Answer: B

The best medium for culture of Francisella tularensis is: A. Bordet-Gengou medium B. cystine glucose blood agar C. Loeffler medium D. charcoal selective medium

Correct Answer: B

The best method to demonstrate the ova of Enterobius vermicularis is: A. acid-ether concentration B. cellophane tape preparation C. formalin-ether concentration D. zinc sulfate flotation

Correct Answer: B

The best procedure to differentiate Listeria monocytogenes from Corynebacterium species is: A. catalase B. motility at 25C C. motility at 35C D. Gram stain

Correct Answer: B

The diagnosis of Neisseria gonorrhoeae in females is best made from: A. clinical history B. an endocervical culture C. a Gram stain of cervical secretions D. examination for clue cells

Correct Answer: B

The genus of virus associated with anogenital warts, cervical dysplasia and neoplasia is: A. herpes simplex virus B. papillomavirus C. cytomegalovirus D. coxsackievirus

Correct Answer: B

The lab has been using a latex agglutination assay to detect Clostridium difficile in stools, which identifies a nontoxin cell wall antigen. The lab is considering adoption of an EIA method that detects Clostridium difficile toxin A. Which of the following would provide the best comparison? A. latex agglutina vs culture on cycloserine cefoxitin-egg-fructose agar B. latex agglutination vs EIA vs cell culture cytotoxin assay C. EIA vs culture on cycloserin cefoxitin-egg-fructose agar D. EIA vs cell culture cytotoxin assay

Correct Answer: B

The mycobacteria that produce a deep yellow or orange pigment both in the dark and light are: A. photochromogens B. scotochromogens C. nonchromogens D. rapid growers

Correct Answer: B

The presence of 20% bile in agar will allow growth of: A. Fusobacterium necrophorum B. Bacteroides ovatus C. Prevotella melaninogenica D. Porphyromonas gingivalis

Correct Answer: B

Three sets of blood cultures were obtained form an adult patient with fever and suspected endocariditis. The aerobic bottle of one set had growth of Staphylococcus epidermidis at 5 days of incubation. this indicates that: A. there was low-grade bacteremia B. the organism is most likely a contaminant C. the patient has a line infection D. the blood culture bottles are defective

Correct Answer: B

Virus transport medium containing penicillin, gentamicin and amphotericin is used to collect and transport specimens for virus culture because this medium: A. enables rapid viral growth during the transport time B. inhibits bacterial and fungal growth C. destroys nonpathogenic viruses D. inhibits complement-fixing antibodies

Correct Answer: B

When evaluating a new susceptibility testing system, if the new system characterizes a susceptible isolate as resistant, this is termed a: A. very major error B. major error C. minor error D. acceptable error

Correct Answer: B

When performing a Kovac indole test, the substrate must contain: A. indole B. tryptophan C. ornithine D. paradimethylaminobenzaldehyde

Correct Answer: B

Two blood cultures are positive for yeast from a patient with an intravenous catheter. One culture grew Candida albicans, while the other Candida krusei. Which medium should the technologies use to subculture the blood bottles to in order to verify that the cultures are pure? A. Sabouraud dextrose agar B. potato dextrose agar C. cornmeal agar D. chromogenic agar

Correct Answer: D

Vibrio parahaemolyticus can be isolated best from feces on: A. eosin methylene blue (EMB) agar B. Hektoen enteric (HE) agar C. Salmonella Shigella (SS) agar D. thiosulfate citrate bile salts (TCBS) agar

Correct Answer: D

Viridans streptococci can be differentiated from Streptococcus pneumoniae by: A. alpha hemolysis B. morphology C. catalase reaction D. bile solubility

Correct Answer: D

What material should be used to prepare slides for direct smear examination for virus detection by special stains or FA technique? A. vesicular fluid B. leukocytes from the edge of the lesion C. the top portion of the vesicle D. epithelial cells from the base of the lesion

Correct Answer: D

When grown in the dark, yellow to orange pigmentation of the colonies is usually demonstrated by: A. Mycobacterium tuberculosis B. Mycobacterium kansasii C. Mycobacterium fortuitum D. Mycobacterium scrofulaceum

Correct Answer: D

A thin, gram-negative bacillus with tapered ends isolated from an empyema specimen grew only on anaerobic sheep blood agar. It was found to be indole positive, lipase negative, and was inhibited by 20% bile. The most probable identification of this isolate would be: A. Bacteroides distasonis B. Prevotella melaninogenica C. Fusobacterium nucleatum D. Clostridium speticum

Correct Answer: C

A yellow colony from a wound culture tested catalase-positive and coagulase-negative. The organism stained as gram-positive cocci in clusters. Which of the following tests would differentiate between a coagulase-negative Staphylococcus and Micrococcus? A. novobiocin susceptibility B. leucin aminopeptidase production C. furazolidone (100 ug/disk) susceptibility D. bile esculin

Correct Answer: C

In the optochin (ethylhydorocupreine hydrochloride) susceptibility test, if there is a zone of inhibition of 19-30 mm surrounding the disk following overnight incubation at 37C, the colony most likely consists of: A. staphylococci B. streptococci C. pneumococci D. intestinal bacilli

Correct Answer: C

Iodine staining of McCoy cell monolayer culture of a cervical swab reveals a large brown intracytoplasmic inclusion. What is the most likely infecting organism? A. cytomegalovirus B. Ehrlichia chaffeensis C. Chlamydia trachomatis D. Rickettsia prowazekii

Correct Answer: C

MacConkey media for screening suspected cases of hemorrhagic E coli 0157:H7 must contain: A. indole B. citrate C. sorbitol D. lactose

Correct Answer: C

Media used to support growth of Legionella pneumophila should contain which of the following additives? A. X and V factors B. hemin and Vitamin K C. charcoal and yeast extract D. dextrose and laked blood

Correct Answer: C

The enterotoxin produced by certain stains of hemolytic, coagulase positive Staphylococcus aureus: A. is destroyed by boiling for 15-30 minutes B. is identical to the dermonecrotic toxin C. causes one type of bacterial food poisoning D. is highly antigenic

Correct Answer: C

The examination of human feces is no help in the detection of: A. Strongyloides stercoralis B. Entamoeba histolytica C. Echinococcus granulosus D. Ancylostoma duodenale

Correct Answer: C

Which one of the following organisms does not require susceptibility testing to the antimicrobial indicated when isolated form a clinically significant source? A. Staphylocoous aureus-clindamycin B. Proteus mirabilis-gentamicin C. Streptococcus pyogenes-penicillin D. Escherichia coli-levofloxacin

Correct Answer: C

Which one of the following results is typical of Campylobacter fetus subspecies fetus? A. optimal growth at 42C B. oxidase negative C. growth at 37C D. catalase negative

Correct Answer: C

Which organism commonly causes food poisoning by consumption of foods containing excessive populations of organisms or preformed enterotoxin? A. Salmonella enteritidis B. Shigella sonnei C. Bacillus cereus D. Escherichia coli

Correct Answer: C

Which organism fails to grow on artificial media or in cell cultures? A. Chlamydia trachomatis B. Neisseria gonorrhoeae C. Treponema pallidum D. herpes simplex virus

Correct Answer: C

While swimming in a lake near his home, a young boy cut his foot, and an infection developed. The culture grew a nonfastidious gram-negative, oxidase positive, beta-hemolytic, motile bacilli that produced deoxyribonuclease. The most likely identification is: A. Enterobacter cloacae B. Serratia marcescens C. Aeromonas hydrophila D. Escherichia coli

Correct Answer: C

"Nutritionally deficient" streptococci are: A. enterococci B. group D nonenterococci C. cell wall-deficient streptococci D. in the genera Granulicatella and Abiotrophia

Correct Answer: D

A 10-year-old boy was admitted to the emergency room with lower right quandrant pain and tenderness. The following laboratory results were obtained: Patient value; Normal range % seg neutrophils: 75%; 16%-60% WBC count: 200 x 10^3/uL (200 x 10^9/L); 13.0 x 10^3/uL (13.0 x 10^9/L) The admitting diagnosis was appendicitis. During surgery the appendix appeared normal; an enlarged node was removed and cultured. Small gram-negative bacilli were isolated form the room temperature plate. The organism most likely is: A. Prevotella melaninogenica B. Shigella sonnei C. Listeria monocytogenes D. Yersinia enterocolitica

Correct Answer: D

A fungus superficially resembles Penicillium species but may be differentiated because its phialides are long and tapering and bend away from the central axis. The most probable identification is: A. Exophiala B. Acremonium C. Cladosporium D. Paecilomyces

Correct Answer: D

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

Correct Answer: D

An isolate on chocolate agar from a patient with epiglottitis was suggestive of Haemphilus species. Additional testing showed that the isolate required NAD for growth and nonhemolytic. The organism is most likely Haemophilus: A. haemolyticus B. ducreyi C. influenzae D. parainfluenzae

Correct Answer: D

An organism isolated form the surface of a skin burn is found to produce a diffusible green pigment on a blood agar plate. Further studies of the organism would most likely show the organism to be: A. Staphylococcus aureus B. Serratia marcescens C. Flavobacterium meningosepticum D. Pseudomonas aeruginosa

Correct Answer: D

Organisms that can be easily identified to the species level form the ova in fecal specimens include: A. Metagonimus yokogawai, Heterophyes heterphyes B. Taenia solium, Taenia saginata C. Necator americanus, Ancylostoma duodenale D. Paragonimus westermani, Hymenolepis nana

Correct Answer: D

Penicillium can best be separated form Aspergillus by: A. color of the colonies B. optimum growth temperature C. presence of rhizoids D. arrangement of the conidia on the conidiosphore

Correct Answer: D

Primary amoebic encephalitis may be caused by: A. Entamoeba coli B. Dientamoeba fragilis C. Endolimax nana D. Naegleria fowleri

Correct Answer: D

Proper media for culture of a urethral discharge from a man include: A. sheep blood and phenylethyl alcohol agars B. eosin-methylene blue and sheep blood agars C. thioglycollate broth and chocolate agar D. chocolate and modified Thayer-Martin agars

Correct Answer: D

Propionibacerium acnes is most often associated with: A. normal oral flora B. post-antibiotic diarrhea C. tooth decay D. blood culture contamination

Correct Answer: D

Quality control of the spot test requires the use of ATCC cultures of: A. Pseudomonase aeruginosa/ Proteus mirabilis B. Salmonella typhi/ Shigella sonnei C. Escherichia coli/ Proteus vulgaris D. Escherichia coli/ Enterobacter cloacae

Correct Answer: D

Refer to the following illustration: See BOC pg 289 Examine the broth microdilution susceptibility test shown above and determine the MIC for gentamicin. A. >64 ug/mL B. 32 ug/mL C. 16 ug/mL D. < 2 ug/mL

Correct Answer: D

Refer to the following illustration: See BOC pg 342 Pic 2 The specimen of choice for finding the above parasite is: A. stool B. duodenal washing C. rectal swab D. scotch tape preparation

Correct Answer: D

Refer to the following image: See BOC pg 338 Trophozoites of the cyst shown above are likely to: A. contain red blood cells B. have clear, pointed pseudopodia C. contain few, if any, vacuoles D. have slow, undefined motility

Correct Answer: D

Rickettsiae infecting man multiply preferentially within which of the following cells? A. reticuloendothelial B. hepatic C. renal tubule D. endothelial

Correct Answer: D

The procedure that assures the most accurate detection of mecA-mediated oxacillin resistance in routine broth microdilution susceptibility testing against S. aureus is: A. addition of 4% NaCl B. incubation at 30 C C. incubation for 48 hours D. use of cefoxitin for testing

Correct Answer: D

The species of mycobacteria that will give a positive niacin test is Mycobacterium: A. leprae B. kansasii C. fortuitum D. tuberculosis

Correct Answer: D

The stock cultures needed for quality control testing of deamination activity are: A. Escherichia coli/ Klebsiella pneumoniae B. Salmonella typhimurium/ Escherichia coli C. Escherichia coli/ Pseudomonas aeruginosa D. Proteus mirabilis/ Escherichia coli

Correct Answer: D

The stock cultures needed for quality control testing of deoxyribonuclease (DNase) production are: A. Salmonella typhimurium/ Escherichia coli B. Escherichia coli/ Pseudomonas aeruginosa C. Proteus mirabilis/ Escherichia coli D. Serratia marcescens/ Escherichia coli

Correct Answer: D

The stock cultures needed for quality control testing of motility are: A. Salmonella typhimurium/ Escherichia coli B. Escherichia coli/ Pseudomonas aeruginosa C. Serratia marcescens/ Escherichia coli D. Klebsiella pneumoniae/ Escherichia coli

Correct Answer: D

The term "internal autoinfection" is generally used in referring to infections with: A. Ascaris lumbricoides B. Necator americanus C. Trichuris trichiura D. Strongyloides stercoralis

Correct Answer: D

To quality control the autoclave, a vial of Bacillus stearothermophilus is autoclaved and should then be: A. inoculated to blood agar B. incubated at 37C C. inoculated to chocolate agar D. incubated at 56C

Correct Answer: D

Tubercle bacilli are specifically stained by: A. crystal violet B. 1% acid fuchsin C. methylene blue D. carbol fuchsin

Correct Answer: D

Respiratory syncytial virus is best isolated using a(n): A. naspharyngeal aspirate B. cough plate C. expectorated sputum D. throat swab

Correct Answer: A

Sodium bicarbonate and sodium citrate are components of which of the following? A. JEMBEC system B. MTM agar C. NYC medium D. ML agar

Correct Answer: A

Structures important in the microscopic identification of Coccidioides immitis are: A. irregular staining, barrel-shaped arthrospores B. tuberculate, thick-walled macroconidia C. thick-walled sporangia containing sporangiospores D. small pyriform microconidia

Correct Answer: A

Which of the following antibiotics would routinely be tested and reported for isolates of Pseudomonas aeruginosa? A. penicillin B. erythromycin C. clindamycin D. gentamicin

Correct Answer: D

Anaerobic susceptibility testing is helpful in the management of patients with: A. synovial infections B. rectal abscesses C. streptococcal pharyngitis D. pilonidal sinuses

Correct Answer: A

Diagnosis of typhoid fever can be confirmed best by culture of: A. stool B. urine C. blood D. bone marrow

Correct Answer: D

Which one of the following combinations of organisms would be appropriate as controls to test the functions listed? A. beta-hemolysis-negative Escherichia coli and Streptococcus pyogenes B. catalase negative Staphylococcus aureus and Staphylococcus epidermidis C. H2S production-negative Proteus mirabilis and Staphylococcus epidermidis D. indole-negative Escherichia coli and Proteus mirabilis

Correct Answer: D

Which one of the following specimen requests is acceptable? A. feces submitted for anaerobic culture B. Foley catheter tip submitted for aerobic culture C. rectal swab submitted for direct smear for gonococci D. urine for culture of acid-fast bacilli

Correct Answer: D

On a culture suspected to be Mycobacterium tuberculosis, the most important test to perform is: A. catalase production B. tellurite reduction C. Tween 80 hydrolysis D. niacin production

Correct Answer: D

An anaerobic, spore-forming, nonmotile, gram-positive bacillus isolated from a foot wound is most likely; A. Actinomyces israelii B. Clostridium perfringens C. Bacillus subtilis D. Eubacterium lentum

Correct Answer: B

An antibiotic that inhibits cell wall synthesis is: A. chloramphenicol B. penicillin C. sulfamethoxazole D. colistin

Correct Answer: B

An antibiotic used to suppress or kill contaiminating fungi in media is: A. penicillin B. cycloheximide C. streptomycin D. amphotericin B

Correct Answer: B

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

Correct Answer: C

A 17-year-old female with cytic fibrosis is diagnosed with pneumonia. A sputum sample grew gram-negative bacilli with yellow, smooth colonies that have the following biochemical reactions: -oxidase: positive -TSI: alk/alk -glucose: oxidized -fluorescence: negative -lysine decarboxylase: positive The most likely organism is: A. Burkholderia cepacia B. Klebsiella pneumoniae C. Shewanella putrefaciens D. Stenotrophomonas maltophilia

Correct Answer: A

A Wright stain on a conjunctival smear from a neonate shows granular cytoplasmic perinuclear inclusions. This is most indicative of: A. Chlamydia trachomatis B. herpes simplex virus C. cytomegalovirus D. variecella-zoster virus

Correct Answer: A

A beta-hemolytic streptococcus that has been isolated form an ear culture grows up to the edge of a 0.04 unit bacitracin disk. Which of the following test would help to determine if the organism is Enterococcus? A. growth in 6.5% NaCl broth B. growth in the presence of penicillin C. optochin susceptibility D. fermentation of 10% lactose

Correct Answer: A

Which one of the following organism could be used as the positive quality control test for lecithinase on egg yolk agar? A. BActeroides fragilis B. Fusobacterium necrophorum C. Clostridium perfringens D. Clostridium sporogenes

Correct Answer: C

An outbreak of Staphylococcus aureus has occurred in a hospital nursery. In order to establish the epidemiological source of the outbreak, the most commonly used typing method is: A. pulsed-field gel electrophoresis B. serological typing C. coagulase testing D. catalase testing

Correct Answer: A

A blood culture bottle with macroscopic signs of growth is Gram stained and the technician notes small, curved gram-negative bacilli resembling "gull wings." It is subcultured to blood and chocolate agar, and incubated aerobically and anaerobically. After 24 hours, not growth is apparent. The next step should be to: A. subculture the bottle, and incubate in microaerophilic conditions B. assume the organism is nonviable, and ask for repeat specimen C. utilize a pyridoxal disk to detect Aeromonas D. subculture the bottle to a medium containing X and V factors

Correct Answer: A

A diabetic foot swab from a 82-year-old woman with recurrent infections is submitted for culture. The Gram stain reveals: -many neutrophils, no squamous epithelial cells -many gram-negative bacilli -many gram-positive cocci in chains The physician requests that all pathogens be worked up. In addition to the sheep blood and MacConkey agar plates routinely used for wound cultures, the technologist might also process a(n): A. CNA agar plate B. chocolate agar plate C. XLD agar plate D. chopped meat glucose

Correct Answer: A

A first morning sputum is received for culture of acid-fast bacilli. It is digested and concentrated by the N-acetyl-L-cysteine alkali method. Two Sabouraud dextrose slants are incubated in the dark at 35C with 5%-10% CO2. The smears reveal acid-fast bacilli, but the slants show no growth after 8 weeks. The explanation is: A. improper media used B. incorrect concentration procedure used C. improper specimen submitted D. exposure to CO2 prevents growth

Correct Answer: A

A gastroenterologis submits a gastric biopsy from a patient with peptic ulcer. To obtain presumptive evidence of Helicobacter pylori, a portion of the specimen should be added to which media? A. urea broth B. tetrathionate C. selenite D. tryptophan

Correct Answer: A

A liquid stool specimen is collected at 10:00 AM and brought to the laboratory for culture and ova and parasite examination. It is refrigerated until 10:10 AM the next day, when the physician requests that the technologist look for amoebic trophozoites. The best course of action would be to: A. request a fresh specimen B. perform a concentration on the original specimen C. perform a trichrome stain on the original specimen D. perform a saline wet mount on the original specimen

Correct Answer: A

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

Correct Answer: A

A urine specimen was submitted for isolation of cytomegalovirus (CMV). The urine was inoculated into human fibroblast tissue culture tubes. After 72 hours, not cytopathic effect was observed in the culture tubes. The most appropriate course of action is to: A. incubate the culture tubes for 2-3 weeks longer B. request a fecal specimen as urine is inappropriate C. repeat the test using monkey kidney cell culture tubes D. request CMV serology as CMV cannot be isolated

Correct Answer: A

AFB smears of a lymph node biopsy from a child are positive. At the end of 8 weeks, the AFB cultures are no growth. To enhance the possibility of recovery of the causative organism, the technologist should: A. incubate the cultures an additional 4 weeks B. add mycobactin J to the media C. transfer the cultures to a 30C incubator D. subculture the liquid culture to chocolate agar

Correct Answer: A

Acceptable specimens for culture of anaerobic bacteria that cause disease include: A. abscesses B. gingival swabs C. skin swabs D. vaginal swabs

Correct Answer: A

After 24 hours a blood culture from a newborn grows catalase-negative, gram-positive cocci. The bacterial colonies are small, translucent and beta-hemolytic on a blood agar plate. Biochemical test results of a pure culture are: -bacitracin: resistant -CAMP reaction: positive -bile esculin: not hydrolyzed -6.5% NaCl broth: no growth Assuming that all controls react properly and reactions are verified, the next step would be to: A. perform a Streptococcus group typing B. report the organism as Streptococcus pneumoniae C. report the organism as Staphyloccus aureus D. report the organism as Staphylococcus epidermidis

Correct Answer: A

An Enterococcus isolated from multiple blood cultures in a patient endocarditis should be: A. screened for high level aminoglycoside resistance B. checked fo tolerance C. assayed for serum antimicrobial activity D. tested for beta-lactamase production

Correct Answer: A

An HIV-positive patient begun to show signs of meningitis. A spinal fluid was collected and cultured for bacteria and fungus. A budding, encapsulated yeast was recovered. Which organism is consistent with this information? A. Crytococcus neoformans B. Aspergillus fumigatus C. Microsporum audouinii D. Sporothrix schenckii

Correct Answer: A

An isolate from a stool culture gives the following growth characteristics and biochemical reactions: -MacConkey agar: colorless colonies -Hektoen agar: yellow-orange colonies -TSI: acid slant/ acid butt, no gas, no H2S -Urea: positive These screening reactions are consistent with which of the following enteric pathogens? A. Yersinia enterocolitica B. Shigella sonnei C. Vibrio parahaemolyticus D. Campylobacter jejuni

Correct Answer: A

An organism has been identified as a member of the fluorescent group of Pseudomonas. Which of the following sets of tests should be used to determine the species os the organism? A. growth at 42C, pyocyanin production, gelatinase production B. pyocyanin production, gelatinase production, OF glucose C. growth at 37C, pyocyanin production, OF glucose D. gelatinase production, growth at 52C, H2S

Correct Answer: A

An organism recovered from a sputum has the following characteristics: -culture: growth at 7 days on Lowenstein-Jensen agar, incubated under aerobic condition siwth CO2 at 35C -Gram sain: delicate branching gram-positive bacilli acid-fast stain: branching, filamentous, "partially" acid-fast bacterium These results are consistent with which of the following genera? A. Nocardia B. Mycobacterium C. Actinomyces D. Streptomyces

Correct Answer: A

An organism that demostrates budding yeast cells with wide capsules in an India ink preparation of spinal fluid is probably: A. Cryptococcus neoformans B. Histoplasma capsulatum C. Blastomyces dermatitidis D. Candida albicans

Correct Answer: A

An organism that exhibits the satellite phenomenon around colonies of staphylococci is: A. Haemophilus influenzae B. Neisseria meningitidis C. Neisseria gonorrhoeae D. Klebsiella pneumoniae

Correct Answer: A

Biochemical reactions of an organism are consistent with Salmonella. A suspension is tested in polyvalent antiserum A through G and Vi antiserum. There is agglutination in the Vi antiserum only. What should be done next? A. boil suspension of the organism for 10 minutes to inactivate the V1 antigen B. test organism with individual antisera for agglutination C. report "no Salmonella isolated" D. repeat biochemical identification of the organism

Correct Answer: A

Chlamydial infections have been implicated in: A. urethritis and conjunctivitis B. gastroenteritis and urethritis C. neonatal penumonia and gastroenteritis D. neonatal meningitis and conjunctivitis

Correct Answer: A

Clinical resistance to penicillin correlates most frequently with beta-lactamase production in: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Streptococcus agalactiae D. Streptococcus pyogenes

Correct Answer: A

Crust from a cauliflower-like lesion on the hand exhibited brown spherical bodies 6-12 um in diameter when examined microscopically. After 3 weeks of incubation at room temperature, a slow-growing black mold grew on Sabouraud dextrose agar. Microscopic examination revealed Cladosporium, Phialophora and Fonsecaea types of sporulation. The probable identification of this organism is: A. Fonsecaea pedrosoi B. Pseudallescheria boydii C. Phialophora verrucosa D. Cladosporium carrionii

Correct Answer: A

Examination of a fungal culture from a bronchial washing reveals white, cottony aerial mycelium. A tease preparation in lactophenol cotton blue shows the structures shown in the image: See BOC pg 325 The most rapid test for definitive identification is: A. nucleic acid probe B. animal inoculation C. exoantigen test D. slide culture

Correct Answer: A

Gram Stain examination form a blood culture bottle shows dark blue, spherical organism in cluster. Growth on sheep blood agar shows small, round, pale yellow colonies. Further tests should include: A. catalase production and coagulase test B. bacitracin susceptibility and serological typing C. oxidase and deoxyribonuclease reactions D. Voges-Proskauer and methyl red reactions

Correct Answer: A

Gram-positive cocci in chains are seen on a Gram stain from a blood culture. The organism grows as a beta-hemolytic colony. Further tests that could be performed include: A. bile esculin, PYR, bacitracin, and hippurate B. catalase and coagulase C. oxidase and deoxyribonuclease D. Voges-Proskauer and methyl red

Correct Answer: A

Group B, beta-hemolytic streptococci may be distinguished form other hemolytic streptococci by which of the following procedure? A. latex antigen typing B. growth in 6.5% NaCl broth C. growth on bile esculin medium D. bacitracin susceptibility

Correct Answer: A

Haemophilus influenzae is most likely considered normal indigenous flora in the: A. oropharynx B. female genital tract C. large intestine D. small intestine

Correct Answer: A

How many hours after eating contaminated food do initial symptoms of staphylococcal food poisoning typically occur? A. 2-6 hours B. 12-18 hours C. 24-48 hours D. 72 hours to a week

Correct Answer: A

In order to isolate Camplobacter coli/jejuni, the fecal specimen should be: A. inoculated onto selective plating media and incubated in reduced oxygen with added CO2 at 42C B. stored in tryptic soy broth before plating to ensure growth of the organism C. inoculated onto selective plating media incubated at both 35C and at room temperature D. incubated at 35C for 2 hours in Cary-Blair media before inoculating onto selective plating media

Correct Answer: A

In processing clinical specimens and fungal isolates, laboratory workers may contract systemic fungal infections through: A. inhalation B. ingestion C. skin contact D. insect vector

Correct Answer: A

In the USA< the most common organism causing eumycotic mycetoma is: A. Pseudallescheria boydii B. Nocardia brasiliensis C. Blastomyces dermatitidis D. Aspergillus fumigatus

Correct Answer: A

Multifocal brain lesion in AIDS patients is commonly caused by: A. Toxoplasma gondii B. Penumocystis jiroveci C. Cryptosporidium parvum D. Giardia lamblia

Correct Answer: A

Mycobacteria that produce pigment only after exposure to light are classified as: A. photochromogens B. scotochromogens C. rapid growers D. nonchromogens

Correct Answer: A

Optimum growth of Campylobacter jejuni is obtained on suitable media incubated at 42C in an atmosphere containing: A. 6% O2, 10%-15% CO2, 85%-90% nitrogen B. 10% H2, 5% CO2, 85% nitrogen C. 10% H2, 10%CO2, 80% nitrogen D. 25% O2, 5% CO2, 70% nitrogen

Correct Answer: A

Plesiomonas shigelloides is a relatively new member of the family Enterobacteriaceae. What characteristic separates it from other members of the Enterobacteriaceae? A. it is oxidase positive B. it ferments glucose C. it produces pyocyanin D. it requires 10% CO2 for growth

Correct Answer: A

Protozoan cysts are found in a wet mount of sediment from ethyl-acetate concentrated material. The cysts are without peripheral chromatic on the nuclear membrane. Each cyst has 4 nuclei, and each nucleus has a large karyosome, which appears as a refractive dot. These oval cysts are most likely: A. Endolimax nana B. Chilomastix mesnili C. Entamoeba histolytica D. Entamoeba harmanni

Correct Answer: A

Refer to the following image: See BOC pg 339 Pic 2 An inexperienced parasitology student may confuse the above organism with: A. Entamoeba histolytica B. Dientamoeba fragilis C. Giardia lamblia D. Trichomonas vaginalis

Correct Answer: A

Refer to the following image: See BOC pg 340 Pic 1 This structure depicts a: A. cyst of a nonpathogenic amoeba B. trophozoite of a nonpathogenic amoeba C. cyst of a pathogenic amoeba D. trophozoite of a pathogenic amoeba

Correct Answer: A

Refer to the following image: See BOC pg 3401 A 24-year-old woman, who just returned form vacationing in Russia, became ill with steatorrheal diarrhea. The above organism was found in her stool. The patient most likely is suffering from: A. giardiasis B. amebiasis C. ascariasis D. balantidiasis

Correct Answer: A

Relapsing fever in humans is caused by: A. Borrelia recurrentis B. Brucella abortus C. Leptospira interrogans D. Spirillum minus

Correct Answer: A

The susceptibility results below are reported on an Enterococcus faecalis isolated form peritoneal fluid. -ampicillin: susceptible -vancomycin: resistant -clindamycin: susceptible -levofloxacin: resistant -linezolid: susceptible The physician calls questioning the results. Which of the following should have been done before the report was released? A. the clindamycin result should have been removed form the report since it is inactive against Enterococcus B. the ampicillin result should have been changed to resistant since the isolate is vamcomycin resistant C. the linezolid result should have been removed form the report since it is inactive against Enterococcus D. ciprofloxacin should have been added to the report since levofloxacin was resistant

Correct Answer: A

Upon review of a sputum Gram stain, the technician notes that the nuclei of all of the neutrophils present in the smear are staining dark blue. The best explanation for this finding is: A. the slide was inadequately decolorized with acetone/alcohol B. the sputum smear was prepared too thin C. the cellular components have stained as expected D. the iodine was omitted from the staining procedure

Correct Answer: A

Ureaplasma urealyticum are difficult to grow in the laboratory on routine media because of their requirement for: A. sterols B. horse blood C. ferric pyrophosphate D. surfactant such as Tween 80

Correct Answer: A

When processing throat swabs for a group A Streptococcus culture, the medium of choice is: A. sheep blood agar B. rabbit blood agar C. human blood agar D. horse blood agar

Correct Answer: A

Which characteristic best differentiates Acinetobacter species from Moraxella species? A. production of indophenol B. growth on MacConkey agar C. motility D. susceptibility to penicillin

Correct Answer: A

Which of following is a dimorphic fungus? A. Sporothrix schenckii B. Candida albicans C. Cryptococcus neofromans D. Aspergillus funigatus

Correct Answer: A

Which of the following is considered a primary drug for the treatment of Mycobacterium tuberculosis? A. rifampin B. kanamycin C. rifabutin D. ethionamide

Correct Answer: A

Which of the following is most often used to prepare a slide from a plate culture of a dermatophyte for microscopic observation? A. lactophenol cotton blue B. potassium hydroxide C. iodine solution D. Gram stain

Correct Answer: A

Which of the following is the most appropriate specimen source and primary media battery? A. endocervical-chocolate, Martin Lewis B. sputum-sheep blod, Thayer-Martin, KV-laked blood C. CSF-Columbia CNA, MacConkey D. urine-sheep blood, chocolate, Columbia CNA

Correct Answer: A

Which of the following media can be used to culture Campylobacter jejuni? A. Skirrow medium B. CIN agar C. anaerobic CNA agar D. bismuth sulfite

Correct Answer: A

Which of the following must be incubated in a microaerophilic environment for optimal recovery of the organism? A. Campylobacter jejuni B. Escherichia coli C. Pseudomonas aeruginosa D. Proteus mirabilis

Correct Answer: A

Which of the following pairs of organism usually grow on kanamycin, vancomycin, laked blood agar? A. Bacteroides and Prevotella B. Mobiluncus and Gardnerella C. Porphyromonas and Enterococcus D. Vellonella and Capnocytophaga

Correct Answer: A

Which of the following reagents should be used as a mucolytic, alkaline reagent for digestion and decontamination of a sputum for mycobacterial culture? A. N-acetyl-L-cystine and NaOH B. NaOH alone C. zephiran-trisodium phosphate D. oxalic acid

Correct Answer: A

Which of the following sets of test best differentiates Salmonella and Citrobacter species? A. KCN, malonate, beta-galactosidase, lysine decarboxylase B. dulcitol, citrate, indole, H2S production C. lactose, adonitol, KCN, motility D. lysine decarboxylase, lactose, sucrose malonate, indole

Correct Answer: A

Which one of the following anaerobes would be negative for indole? A. Bacteroides fragilis B. Fusobacterium nucleatum C. Porhyromonas asaccharolytica D. Proteus mirabilis

Correct Answer: A

Which one of the following results is typical of Campylobacter jejuni: A. optimal growth at 42C B. oxidase negative C. Catalase negative D. nonmotile

Correct Answer: A

Which one of the following species of Mycobacterium does not usually fluoresce on fluorochrome stain? A. Mycobacterium fortuitum B. Mycobacterium tuberculosis C. Mycobacterium ulcerans D. Mycobacterium bovis

Correct Answer: A

Which organism is the most common anaerobic bacteria isolated from infectious processes of soft tissue and anaerobic bacteremia? A. Bacteroides fragilis B. Fusobacterium nucleatum C. Porphyromonas asaccharolytica D. Clostridium perfringes

Correct Answer: A

Which selective medium is used for the isolation of gram-positive microorganism? A. Columbia CNA with 5% sheep blood B. trypticase soy agar with 5% sheep blood C. eosin methylene blue D. modified Thayer-Martin

Correct Answer: A

Which type of microscope would be most useful in examining viruses and the structure of microbial cells? A. electron B. phase-contrast C. dark-field D. bright-field

Correct Answer: A

>100,000 CFU/mL of a gram-negative bacilli were isolated on MacConkey from a urine specimen. Biochemical results are as follows: -glucose: acid, gas produced -indole: negative -urea: positive -TDA: positive -H2S: positive The organism is most likely: A. Morganella morganii B. Proteus mirabilis C. Proteus vulgaris D. Providencia stuartii

Correct Answer: B

A 2-week-old culture of a urine specimen produced a few colonies of acid-fast bacilli, which were rough and nonpigmented. The niacin test was weakly positive and the nitrate test was positive. Which of the following is the most appropriate action when a presumptive identification has been requested as soon as possible? A. report the organism as presumptive Mycobacterium tuberculosis B. wait a few days and repeat the niacin test; report presumptive Mycobacterium tuberculosis if the test is more strongly positive C. subculture the organism and set up the routine battery of biochemicals; notify the physician that results will not be available for 3 weeks D. set up a thiophene-2-carboxylic acid hydrazide (T2H); if the organism is sensitive, report Mycobacterium bovis

Correct Answer: B

A D test is performed on an isolate of Staphylococcus aureus to determine inducible clindamycin resistance: See BOC pg 291 Based on the result seen in the image how should the erythromycin and clindamycin be reported? A. erythromycin: resistant; clindamycin resistant B. erythromycin: resistant; clindamycin susceptible C. erythromycin: susceptible; clindamycin: resistant D. erythromycin: susceptible; clindamycin; susceptible

Correct Answer: B

A Gram stain performed on a sputum specimen revealed gram-negative diplococci within PMNs. Oxidase testing is positive and carbohydrate degradation tests are inert. The organism is: A. Neisseria lactamica B. Moraxella catarrhalis C. Neisseria meningitidis D. Neisseria sicca

Correct Answer: B

A beta-hemolytic streptococci that is bacitracin-sensitive and CAMP-negative is: A. group A or B B. group A C. beta-hemolytic, not group A, B, or D D. beta-hemolytic, group D

Correct Answer: B

A cerebrospinal fluid has been inoculated onto sheep blood and chocolate agar plates and into a tube of trypticase soy broth. All media were incubated in an atmosphere of 5% CO2. Which of the following organisms would usually be isolated by this procedure? A. Francisella tularensis B. Haemophilus influenzae C. Bordetella pertusis D. Bacteroides fragilis

Correct Answer: B

A child was bitten on the arm by her sibling and the resulting wound grew a slender gram-negative bacilli that has the following characteristics: -growth on SBA: colonies that "pit" the agar -colonies odor: like bleach -catalase: negative -oxidase: positive -TSI: no growth The identification of this organism is: A. Moraxella catarrhalis B. Eikenella corrodens C. Kingella kingae D. Legionella pneumophila

Correct Answer: B

A control strain of Clostridium should be used an anaerobe jar to assure: A. that plate media is working B. that an anaerobic environment is achieved C. that the jar is filled with a sufficient number of plates D. that the indicator strip is checked

Correct Answer: B

A fecal specimen, inoculated to xylose lysine deoxycholate (XLD) and Hektoen enteric (HE) produced colonies with black centers. Additional testing results are as follows: Biochemical Screen; Result; Serological Screen; Result -glucose: pos; polyvalent: no agglutination -H2S: pos; group A: no agglutination -lysine decarboxylase: pos; group B1: no agglutination -urea: neg; group C: no agglutination -ONPG: neg; group D: no agglutination -indole: pos; group Vi: no agglutination The most probable identification is: A. Salmonella enterica B. Edwardsiella tarda C. Proteus mirabilis D. Shigella sonnei

Correct Answer: B

A genus that is found in soil and water and causes infections in immunocompromised patients has the following characteristics: -sheep blood agar: violet pigment -MacConkey agar: growth -42C incubation: growth -oxidase: positive -OF glucose: fermenter -indole: negative The genus is: A. Campylobacter B. Chromobacterium C. Aeromonas D. Serratia

Correct Answer: B

A gram-negative bacillus with bipolar staining was isolated from a wound infection caused by a bite from a pet cat. The following characteristic reactions were seen: -oxidase: positive -glucose OF: fermentative -catalase: positive -motility: negative -MacConkey agar: no growth Which of the following is the most likely organism? A. Pseudomonas aeruginosa B. Pasteurella multocida C. Aeromonas hydrophila D. Vibrio cholerae

Correct Answer: B

A gram-negative diplococcus that grows on modified Thayer-Martin medium can be further confirmed as Neisseria gonorrhoeae if it is: A. oxidase postive, glucose positive, and maltose postive B. oxidase postive and glucose postive, maltose negative C. oxidase positive and maltose positive, glucose negative D. glucose positive, oxidase negative and maltose negative

Correct Answer: B

A light yellow colony from a skin lesion grew aerobically and tested as catalase positive and coagulase negative. The organism gram stained as positive cocci in clusters. The organism was modified oxidase positive, bacitracin (0.04U) susceptible and resistance to lysostaphin. What is the identification of this organism? A. Staphylococcus aureus B. Micrococcus luteus C. Staphylococcus epidermidis D. Peptostreptococcus anaerobius

Correct Answer: B

A liquid fecal specimen form a 3-month-old infant is submitted for microbiological examination. In addition to culture on routine media for Salmonella and Shigella, this specimen should routinely, A. examined for the presence of Entamoeba hartmanni B. examined for the presence of Camplybacter sp C. screened for the detection of enterotoxigenic Escherichia coli D. placed in thioglycollate broth to detect Clostridium botulinum

Correct Answer: B

A mold grown at 25C exhibited delicate septate hyaline hyphae and many conidiophores extending at right angles from the hyphae. Oval, 2-5 um conidia were formed at the end of the conidiophores giving a flowerlike appearance. In some areas "sleeves" of spores could be found along the hyphae as well. A 37C culture of this organism produced small, cigar-shaped yeast cells. This organism is most likely: A. Histoplasma capsulatum B. Sporothrix schenckii C. Blastomyces dermatitidis D. Acremonium falciforme

Correct Answer: B

A neonatal blood culture collected through a catheter grows a small yeast. Microscopically, the yeast appear round at one end, with a budlike structure on a broad base at the other end. Growth is enhanced around olive oil-saturated discs. The organism isolated is: A. Candida tropicalis B. Malassezia furfur C. Candida lipolytica D. Malassezia pachydermatis

Correct Answer: B

A patient has a suspected diagnosis of subacute bacterial endocarditis. His blood cultures grow non-spore-forming pleomorphic gram-positive bacilli only in the anaerobic bottle. What test(s) will give a presumptive identification of this microorganism? A. beta-hemolysis and oxidase B. catalase and spot indole C. esculin hydrolysis D. hydrolysis of gelatin

Correct Answer: B

A patient is suspected of having amebic dysentery. Upon microscopic examination of a fresh fecal specimen for ova and parasites, the following data were obtained: -a trophozoite of 25 um -progressive, unidirectional crawl -evenly distributed peripheral chromatin -finely granular cytoplasm This information probably indicates: A. Entamoeba coli B. Entamoeba histolytica C. Endolimax nana D. Iodamoeba butschlii

Correct Answer: B

A penicillin-resistant Neisseria gonorrhoeae produces: A. alpha-hemolysin B. beta-lactamase C. enterotoxin D. coagulase

Correct Answer: B

A physician calls the laboratory to verify a result of Mycobacterium tuberculosis, stating that the clinical history of the patient is not compatible with tuberculosis. On review of the patient's culture, the smear was negative and the culture become positive at 5 weeks in the broth culture only. Additionally, it was determined that another patient's specimen that was processed the same day was 4+ AFB on smear and the culture was positive at 10 days for Mycobacterium tuberculosis. The lab should: A. include a positive control when processing specimens B. perform molecular fingerprinting on both isolates C. repeat the nucleic acid probe D. set up susceptibility tests

Correct Answer: B

A pregnant patient is creened at 36 weeks gestation for group B streptococcus (GBS). A vaginal swab is collected and cultured in Todd-Hewitt broth with 8 ug gentamicin/mL and 15 ug nalidixic acid/mL. The broth is subcultured onto sheep blood agar after 24 hours of incubation. No GBS are seen on the subculture and the results are reported as negative. The patient later goes on to deliver an infant with early onset GBS disease. What is the most likely reason for the negative GBS culture? A. the patient was screened to early since screening after 38 weeks is recommended B. a vaginal swab was collect instead of a vaginal/rectal swab C. the Todd-Hewitt broth used was inhibitory to the organism D. the selective broth was incubated only 24 hours before subculture

Correct Answer: B

A reliable test for distinguishing Staphylococcus aureus form other staphylococci is: A. oxidase B. coagulase C. catalase D. optochin susceptibility

Correct Answer: B

A small, gram-negative bacillus is isolated form an eye culture. It grows only on chocolate agar and is oxidase-variable. The most likely organism is: A. Acinetobacter lwoffi B. Haemophilus influenzae C. Stenotrophomonas maltophilia D. Pseudomonas aeruginosa

Correct Answer: B

A smear of skin tissue reveals fluorescent septate hyphae. The smear was prepared using: A. acridine orange B. calcofluor white C. auramine rhodamine D. periodic acid-Schiff

Correct Answer: B

A specimen of hair that fluoresced under a Wood lamp was obtained from a child with low-grade scaling lesion of the scalp. Cultures revealed a fungus with mycelium and very few macroconidia or microconidia. This fungus is most likely: A. Microsporum gypseum B. Microsporum audouinii C. Trichophyton tonsurans D. Epidermophyton floccosum

Correct Answer: B

A sputum culture ffrom an alcoholic seen in the ER grows gray, mucoid, stringy colonies on sheep blood agar. The isolate grows readily on MacConkey agar and forms mucoid, dark pink colonies. The colonies yield the following test results: -ONPG: + -indole: = -glucose: + -oxidase: = -citrate: + -VP: + The organism is most likely: A. Edwardsiella tarda B. Klebsiella pneumoniae C. Escherichia coli D. Proteus vulgaris

Correct Answer: B

A sputum specimen received at 8 AM for an AFB smear reveals acid-fast bacilli. an additional sputum is submitted that afternoon. This specimen was concentrated by the NALC-sodium hydroxide method and inoculated on 2 Lowenstein-Jensen slants and held for 8 weeks at 35C in 5%-10% CO2. No growth occurs. The best explanation is that: A. the hypochlorite technique was not used B. an improper specimen was submitted for culture C. improper media was used for culture D. cultures were held for an insufficient period of time

Correct Answer: B

A stool specimen for ova and parasite examination contained numerous rhabditiform larvae. Which factor does not aid in the identification of larvae? A. larva tail morphology B. type of water vegetation consumed C. length of the buccal cavity D. appearance of the genital primordium

Correct Answer: B

A urine Gram stain shows gram-positive cocci in clusters. The organism tested catalase positive. To speciate this organism from culture, the technician should perform a coagulase test and a/an: A. polymyxin B susceptibility B. novobiocin susceptibility C. oxidase D. beta-lactamase

Correct Answer: B

A urine culture had the following culture results: -sheep blood: swarming -Columbia CNA: no growth -MacConkey: 1. >100,000 CFU/mL nonlactose-fermenter 2. >100,000 CFU/mL nonlactose-fermenter with red pigment The isolates form MacConkey agar had the following biochemical reactions: Test; Isolate 1; Isolate 2 -TSI: alk/acid; alk/acid -Urea: pos; neg -TDA: pos; neg -H2S: pos; neg The organism are most likely: A. Proteus vulgaris and Enterobacter cloacae B. Proteus mirabilis and Serratia marcescens C. Morganella morganii and Klebsiella penumoniae D. Providencia stuartii and Serratia liquefaciens

Correct Answer: B

A vaginal/rectal swab is collected form a pregnant patient to screen for group B Streptococcus colonization. What is the best medium to use for specimen inoculation? A. blood agar B. LIM broth C. CNA agar D. thioglycollate broth

Correct Answer: B

AFB smear positive respiratory specimens may be reliable identified as Mycobacterium tuberculosis the same day the smear was read by: A. cording seen on the AFB smear B. nucleic acid amplification C. QuantiFERON -TB test D. DNA probes

Correct Answer: B

Acinetobacter lwoffi differs from Neisseria gonorrhoeae in that the former: A. exhibits a gram-negative staining reaction B. will grow on MacConkey and EMB media C. is indophenol oxidase-positive D. produces hydrogen sulfide on a TSI slant

Correct Answer: B

After satisfactory performance of daily disk diffusion susceptibility quality control is documented, the frequency of quality control can be reduced to: A. twice a week B. every week C. every other week D. every month

Correct Answer: B

An AFB broth culture is positive for acid-fast bacilli at 1 week while the agar slant shows no growth. The most likely explanation for this is: A. the organism is a contaminant B. AFB grow more rapidly in liquid media C. PANTA was added to the broth D. the agar slant was incubated in 5% CO2

Correct Answer: B

An acid-fast bacillus recovered from an induced sputum had the following characteristics: -pigmentation: yellow in the dark, turning a deeper yellow-orange after 2 weeks of light exposure -nitrate reduction: negative -Tween hydrolysis: positive at 5-10 -urease: negative Based on this information, the organism is most likely Mycobacterium: A. scrofulaceum B. gordonae C. szulgai D. flavescens

Correct Answer: B

An anaerobic gram-positive bacilli with subterminal spores was isolated from a peritoneal abscess. The most likely identification of this organism is: A. Bacillus cereus B. Clostridium septicum C. Eubacterium lentum D. Bifidobacterium dentium

Correct Answer: B

When performing a stool culture, a colony type typical of an enteric pathogen is subcultured on a blood agar plate. The resulting pure culture is screened with several tests to obtain the following results: -TSI: acid butt, alkaline slant, no gas, no H2S -phenylalanine deaminase: negative -motility: positive -serological typing: Shigella flexneri (shigella subgroup B) The serological typing is verified with new kit and controls. The best course of action would be to: A. report the organism as Shigella flexneri without further testing B. verify reactivity of motility medium with positive and negative controls C. verify reactivity of the TSI slants with positive and negative controls for H2S production D. verify reactivity of phenylalanine deaminase with positive and negative controls

Correct Answer: B

When staining acid-fast bacilli with Truant auramine-rhodamine stain, potassium permanganate is used as a: A. decolorizing agent B. quenching agent C. mordant D. dye

Correct Answer: B

Which 2 diseases are usually preceded by infection with beta-hemolytic streptococci? A. rheumatic fever, undulant fever B. glomerulonephritis, rheumatic fever C. rheumatic fever, tularemia D. glomerulonephritis, undulant fever

Correct Answer: B

Which of the 2 different antimicrobial agents listed below are commonly used and may result in synergistic action in the treatment of endocariditis caused by Enterococcus faecalis? A. an aminoglycoside and a macrolide B. a penicillin derivative and aminoglycoside C. a cell membrane active agent and nalidixic acid D. a macrolide and a penicillin derivative

Correct Answer: B

Which of the following characterisitics best distinguishes Mycobacterium scrofulaceum from Mycobacterium gordonae? A. iron uptake B. Tween hydrolysis C. good growth at 25C D. niacin production

Correct Answer: B

Which of the following clean catch urine culture colony counts indicates the patient likely has a urinary tract infection? A. 10^1 CFU/mL B. 10^3 CFU/mL C. 10^5 CFU/mL D. no growth

Correct Answer: B

Which of the following combinations of media provides an egg base, and a selective egg or agar base media? A. Lowenstein-Jensen, american Thoracic Society (ATS), Middlebrook 7H11 B. Lowenstein-Jensen, Middlebrook 7H11, Lowenstein-Jensen Gruft C. Middlebrook 7H10, Petragnani, Lowenstein-Jensen D. Middlebrook 7H10, Middlebrook 7H11, Mitchison 7H11

Correct Answer: B

Which of the following factors would make an organism appear to be more resistant on a disk diffusion susceptibility test? A. too little agar in the plate B. too many organism in the inoculum C. the presence of 0.5% NaCl in the medium D. a medium with a pH of 7.4

Correct Answer: B

Which of the following indicates the presence of a viral infection in tissue smears or biopsies? A. cytopathic effect B. intranuclear inclusions C. cell lysis D. mononuclear inflammatory cells

Correct Answer: B

Which of the following is the most important variable in the recovery of organisms in patients with bacteremia? A. subculture of all bottles at day 5 incubation B. the volume of blood cultured C. use of chlorhexadine for skin antisepsis D. collection of multiple blood culture sets from a single venipuncture

Correct Answer: B

Which of the following organisms can grow in the small bowel and cause diarrhea in children, traveler's diarrhea, or a severe cholera-like syndrome through the production of enterotoxins? A. Yersinia enterocolitica B. Escherichia coli C. Salmonella typhi D. Shigella dysenteriae

Correct Answer: B

Which of the following procedures should be performed to confirm that an unknown mold is one of the pathogenic dimorphic fungi: A. animal inoculation B. culture conversion to yeast form C. demonstration of sexual and asexual reproduction D. serological studies

Correct Answer: B

Which species of Mycobacterium includes a BCG stain used for vaccination against tuberculosis? A. tuberculosis B. bovis C. kansasii D. fortuitum/chelonae complex

Correct Answer: B

A 1-2mm translucent, nonpigmented colony, isolated from an anaerobic culture of a lung abscess after 72 hours, was found to fluoresce brick-red under ultraviolet light. A gram stain of the organism revealed a coccobacillus that had the following characterisitcs: -growth in bile: inhibited -vancomycin: resistant -kanamycin: resistant -colistin: susceptible -catalase: negative -esculin hydrolysis: negative -indole: negative The identification of this isolate is: A. Bacteriodes ovatus B. Prevotella oralis C. Prevotella melaninogenica D. Porphyromonas assaccharolytica

Correct Answer: C

A 10-year-old child with systic fibrosis presents with cough and shortness of breath. Her sputum Gram stain is seen in the image: See BOC pg 292 Pic 2 Based on the Gram stain what would be the best medium and incubation condition to optimize recovery of the organism seen? A. MacConkey agar incubated in CO2 B. Tinsdale agar incubated in ambient air C. chocolate agar incubated in CO2 D. CNA agar incubated in ambient air

Correct Answer: C

A 4-year-old is admitted with symptoms of meningitis, and a Gram stain of the cerebrospinal fluid reveals small, pleomorphic, gram-negative coccobacilli. After 24 hours incubation at 35C, small, moist, gray colonies, which are oxidase variable, are found on the chocolate agar plate only. Which of the following biochemical data would be consistent with this isolate? A. -CTA dextrose positive -CTA maltose: positive -ONPG: negative B. -sodium hippurate hydrolysis: positive -A disc: negative -CAMP test: positive C. -X factor: no growth -V factor: no growth -XV factor: growth -horse blood: no hemolysis D. -catalase: positive -esculin hydrolysis: positive -methyl red: positive -"umbrella" motility at room temperature

Correct Answer: C

A 44-year-old man was admitted to the hospital following a 2-week history of low-grade fever, malaise and anorexia. Examination of a Giemsa stain revealed many intraerythrocytic parasites. Further history revealed frequent camping trips near Martha's Vineyard and Nantucket Island, but no travel outside the continental United States. This parasite could easily be confused with: A. Trypanosoma cruzi B. Trypanosoma rhodesiense/ gambiense C. Plasmodium falciparum D. Leishmania donovani

Correct Answer: C

A technologist is reading a Gram stain from a CSF and observes many neutrophils and lancet-shaped gram-positive diplococci. Which set of chemistry and hematology CSF results would most likely be seen in someone with this type of infection? CSF results: WBC; Glucose; Protein -A: inc, inc, inc -B: dec, dec, dec -C: inc, dec, inc -D: dec, inc, dec A. result A B. result B C. result C D. result D

Correct Answer: C

A 64-year-old male with lymphoma has a positive blood culture at 18 hours incubation. The organism is a nonlactose fermenting gram-negative bacillus on MacConkey agar. Further testing gives the following reactions: -oxidase: neg -TSI: alkaline/acid, no hydrogen sulfide -motility: pos -indole: pos -citrated: pos -ornithine decarboxylase: neg -urea: pos -phenylalanine deaminase: pos -VP: neg This genus is: A. Morganella B. Proteus C. Providencia D. Serratia

Correct Answer: C

A Gram stain of a touch prep from a gastric biopsy shows gram-negative bacilli that are slender and curved. The most likely pathogen is: A. Burkholderia cepacia B. Corynebacterium urealyticum C. Helicobacter pylori D. Pasteurella multocida

Correct Answer: C

A beta-hemolytic Streptococcus that is bacitracin-resistant and CAMP-positive is: A. group A or B B. group A C. group B D. beta-hemolytic, group D

Correct Answer: C

A beta-hemolytic gram-positive coccus was isolated from the cerebrospinal fluid of a 2-day-old infant with signs of meningitis. The isolate grew on sheep blood agar under aerobic conditions and was resistant to a bacitracin disc. Which of the following should be performed for the identification of the organism? A. oxidase production B. catalase formation C. latex antigen typing D. esculin hydrolysis

Correct Answer: C

A catheterized urine is inoculated onto blood and MacConkey agar using a 0.01 mL loop. After 48 hours, 68 colonies of a small translucent nonhemolytic organism grew on blood agar but not MacConkey. Testing reveals small gram-positivie, catalase-negative cocci. The preliminary report and follow-up testing would be: A. growth of 689 colonies/mL of gram-positive cocci, optochin and bacitracin susceptibility test B. growth of 6,800 colonies/mL of a Staphylococcus species, coagulase test to follow C. growth of 6,800 colonies/mL of a Streptococcus species, esculin hydrolysis and NaCl growth test to follow D. growth of 6,800 colonies/mL of a Streptococcus species, no further testing

Correct Answer: C

A clean catch urine sample form a nursing home patient is cultured using a 0.001 mL loop. It grows 67 colonies of a lactose fermenter that has the following biochemical reactions: -TSI: acid/acid -oxidase: neg -motility: pos -indole: neg -citrate: pos -VP: pos -lysine decarboxylase: neg -ornithine decarboxylase: pos -urea: neg What should the microbiologist report? A. 670 CFU/mL Serratia marsecens sp B. 6,700 CFU/mL Providencia stuartii C. 67,000 CFU/mL Enterobacter cloacae D. 67,000 CFU/mL Klebsiella oxytoca

Correct Answer: C

A digested and decontaminate sputum is inoculated into a Bactec 12B bottle and incubated in air at 37C. On day 14, a positive growth index is obtained, and the auramine-rhodamine stain is positive. Broth form the initial bottle is inoculated into one Bactec 12B bottle, and one Bactec 12B bottle with NAP. After reincubation, the inoculated growth bottle shows an increase in growth index, while the bottle containing NAP shows no increase. The organism cultured form the sputum is most likely Mycobacterium: A. marinum B. kansaii C. tuberculosis D. avium-intracellulare

Correct Answer: C

A fibrous skin module is removed from the back of a patient from Central America. A microfilaria seen upon microscopic exam of the nodule is : A. Wuchereria bancrofti B. Brugia malayi C. Onchocerca volvulus D. Loa Loa

Correct Answer: C

A fungal isolate form the sputum of a patient with a pulmonary infection is suspected to be Histoplasma capsulatum. Tuberculate macroconidia were seen on the hyphae of the mold phase, which was isolated at room temperature on Sabouraud dextrose agar containing chloramphenicol and cyclohximide (SDA-CC). A parallel set of cultures incubated at 35C showed bacterial growth on SDA, but no growth on SDA-CC. Which of the following is the appropriate course of action? A. repeat subculture of the mold phase to tubes of moist SDA-CC, incubate at 35C B. subculture the mold phase to tubes of moist BHI-blood media, incubate at 25C C. subculture the mold phase to moist BHI-blood media, incubate at 35C D. perform animal inoculation studies

Correct Answer: C

A gamma-hemolytic Streptococcus that blackens bile esculin agar but does not grow in 6.5% NaCl broth is most likely: A. group B Streptococcus B. Enterococcus C. group D streptococcus D. Streptococcus pneumoniae

Correct Answer: C

A gram stain of a necrotic wound specimen showed large gram-positive bacilli. There was 3+ growth on anaerobic media only, with colonies producing a double zone hemolysis. To identify the organism, the microbiologist should: A. determine if the organism ferments glucose B. perform the oxidase test C. set up egg yolk agar plate D. test for bile tolerance

Correct Answer: C

A jaundiced 7-year-old boy, with a history of playing in a pond in a rat-infested are, has a urine specimen submitted for a direct darkfield examination. No organism are seen in the specimen. Which medium should be inoculated in an attempt to isolate the suspected organism? A. blood cysteine dextrose B. PPLO agar C. Fletcher semisolid D. chopped meat glucose

Correct Answer: C

A medium that aids in the presumptive identification of organism based on their appearance on the medium is called: A. enriched B. selective C. differential D. specialized

Correct Answer: C

A mycobacterial isolate that causes multiple skin nodules, grows at 30C and requires hemin for growth is Mycobacterium: A. marinum B. genavense C. haemophilum D. xenopi

Correct Answer: C

A positive niacin test is most characteristic of Mycobacterium: A. chelonae B. marinum C. tuberculosis D. xenopi

Correct Answer: C

A sputum specimen from a patien with a known Klebsiella pneumoniae infection is recieved in the laboratory for fungus culture. The proper procedure for handling this specimen is to: A. reject the current specimen and request a repeat culture when the bacterial organism is no longer B. incubate culture tubes at room temperature in order to inhibit the bacterial organism C. include media that have cycloheximide and chloramphenicol added to inhibit bacterial organism s and saprophytic fungi D. perform a direct PAS stain; if no fungal organism are seen, reject the specimen

Correct Answer: C

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

Correct Answer: C

An 8-year-old girl was admitted to the hospital with a 3-day history of fever, abdominal pain, diarrhea, and vomiting. A stool culture grew many lactose-negative colonies that yielded the following test results: -oxidase: negative -TSI: acid slant/acid butt -indole: neg -urease: pos -ornithine decarboxylase: pos -sucrose: pos -H2S: neg -motility at 25C: pos The most probable identification of this organism is: A. Escherichia coli B. Providencia stuartii C. Yersinia enterocolitica D. Edwardsiella tarda

Correct Answer: C

An isolate form a cornea infection had the following culture results: -Sabouraud dextrose: white & cottony at 2 days, rose color at 6 days -Slide culture: slender sickle shape macroconidia The most likely organism is: A. Acremonium B. Aspergillus C. Fusarium D. Geotrichum

Correct Answer: C

An organism gave the following reactions: -TSI: acid slant/acid butt; no H2S gas produced -Indole: positive -Motility: positive -Citrate: negative -Lysine decarboxylase: positive -Urea: negative -VP: negative This organisms most likely is: A. Klebsiella pneumoniae B. Shigella dysenteriae C. Escherichia coli D. Enterobacteria cloacae

Correct Answer: C

An organism was inoculated to a TSI tube and gave the following reactions: -alkaline slant/acid butt H2S gas produced This organism most likely is: A. Klebsiella pneumoniae B. Shigella dysenteriae C. Salmonella typhimurium D. Escherichia coli

Correct Answer: C

Anaerobic infections differ from aerobic infections in which of the following? A. they usually respond favorably with aminoglycoside therapy B. they usually arise from exogenous sources C. they are usually polymicrobic D. Gram stains of specimens are less helpful in diagnosis

Correct Answer: C

Cerebrospinal fluid from a febrile 25-year-old man with possible meningitis is rushed to the laboratory for a stat Gram stain and culture. While performing the Gram stain, the technologist accidentally spills most of the specimen. The smear shows many neutrophils and no microorganism. Since there is only enough CSF to inoculate one plate, the technologist should use a: A. blood agar plate B. chopped meat glucose C. chocolate agar plate D. Thayer-Martin plate

Correct Answer: C

Characteristics of the HACEK group of bacteria include: A. association with urinary tract infections B. Gram stain of pleomorphic gram-positive bacilli C. requirement of 5%-10% CO2 for growth D. requirement of 42C for growth

Correct Answer: C

Culture of a strand of hair, that fluoresced yellow-green when examined with a Wood lamp, produced a slow-growing, flat gray colony with a salmon-pink reverse. Microscopic examination demonstrated racquet hyphae, pectinate bodies, chlamydospores, and a few abortive or bizarre-shaped macroconidia. The most probable identification of this isolate is: A. Epidermophyton floccosum B. Microsporum canis C. Microsporum audouinii D. Trichophyton rubrum

Correct Answer: C

Darkfield microscopy is can be used to visualize: A. Pseudomonas aeruginosa B. Streptococcus pneumoniae C. Treponema pallidum D. Legionella pneumophila

Correct Answer: C

During the past month, Staphylococcus epidermidis has been isolated form blood cultures at 2-3 times the rate form the previous year. The most logical explanation for th eincrease in these isolates is that: A. the blood culture media are contaminated with this organism B. the hospital ventilation system is contaminated with Staphylococcus epidermidis C. there has been a break in proper skin preparation before drawing blood for culture D. a relatively virulent isolate is being spread from patient to patient

Correct Answer: C

Establishing the pathogenicity of a microorganism isolated form a child's throat and identified as Corynebacterium diphtheria would depend upon: A. the morphological appearance as revealed by Gram stain B. the type of hemolysis of blood agar C. a positive toxigenicity test D. the appearance of growth on Tinsdale tellurite agar

Correct Answer: C

First-generation cephalosporins can be adequately represented by: A. cefotetan B. ceftriaxone C. cephalothin D. cefoxitin

Correct Answer: C

Fluid from a cutaneous black lesion was submitted for routine bacterial culture. After 18 hours of incubation at 35C there was no growth on MacConkey agar, but 3+ growth on sheep blood agar. The colonies were nonhemolytic, nonmotile, 4-5 mm in diameter and off-white with aground glass appearance. Each colony had an irregular edge with comma-shape outgrowths that stood up like "beaten egg whites" when gently lifted with an inoculating needle. A Gram stain of a typical colony shoewd large, gram-positive rectangular bacilli. The organism is most likely: A. Clostridium perfringens B. Aeromonas hydrophila C. Bacillus anthracis D. Mycobacterium marinum

Correct Answer: C

Gram stain examination of a CSF specimen indicates the presence of yeast-like cells with gram-positive granular inclusions. Which of the following techniques should be used next to assist in the identification of this organism? A. 10% KOH B. lactophenol cotton blue C. India ink D. periodic acid-Schiff

Correct Answer: C

In a disk diffusion susceptibility test, which of the following can result if disks are placed on the inoculated media and left at room temperature for an hour before incubation? A. the antibiotic would not diffuse into the medium, resulting in no zones B. zones of smaller diameter would result C. zones of larger diameter would result D. there would be no effect on the final zone diameter

Correct Answer: C

In a quality control procedure on a new batch of Mueller-Hinton plates using a stock culture of Staphylococcus aureus (ATCC 25923), all the disk zones sizes are too small. The most likely reason for this is that the: A. Mueller-Hinton plates were poured too thin B. potency of the antibiotic disks is too high C. bacterial suspension was not diluted to the proper concentration D. disks should have been set up on mannitol salt

Correct Answer: C

In preparing an India ink slide, the technician should ensure that the: A. CSF is unspun B. sputum is well mixed C. proper amount of reagent is added D. slide is properly dried first

Correct Answer: C

In the Kirby-Bauer disc diffusion susceptibility test, which variable is critical when testing Pseudomonas species for antibiotic susceptibility to aminoglycosides? A. incubation temperature B. duration of incubation C. cation content of media D. depth of agar

Correct Answer: C

Multiple blood clutures fraom a pateint with endocarditis grew a facultatively anaerobic, pleomorphic gram-negative bacilli with the following characteristics: -hemolysis: negative -MacConkey agar: no growth -sheep blood agar: growth in 5%-10% CO2 -chocolate agar: growth in 5%-10% CO2 -catalase: negative -V factor: not required -X factor: not required -oxidase: negative -nitrate: positive, reduced to nitrites -indole: negative The most likely identification is: A. Brucella abortus B. Actinobacillus actinomycetemcomitans C. Haemophilus aphrophilus D. Cardiobacterium hominis

Correct Answer: C

Mycoplasmas differ from bacteria in that they: A. do not cause disease in humans B. cannot grow in artificial inanimate media C. lack cell walls D. are not serologically antigenic

Correct Answer: C

On day 3 of a fungal culture, grayish cottony growth is observed that is filling the container. The most likely mold isolated is a: A. dermatophyte B. dimorphic mold C. zygomycete D. dematiaceous mold

Correct Answer: C

One of the enterotoxins produced by enterotoxigenic Escherichia coli in traveler's diarrhea is similar to a toxin produced by: A. Clostridium perfringes B. Clostridium difficile C. Vibrio cholerae D. Yersinia enterocolitica

Correct Answer: C

Penicillium species is isolated from a bone marrow culture of a patient that travelled to southeast Asia. After 7 days the isolate produces a red pigment that diffuses into the medium. The technologist should: A. prepare a slide culture B. repeat the tease preparation C. transfer a colony to BHI at 35C D. perform a nucleic acid probe

Correct Answer: C

Polyvinyl alcohol used in the preparation of permanently stained smears of fecal material: A. concentrates eggs B. dissolves artifacts C. serves as an adhesive D. enhances stain penetration

Correct Answer: C

Proper collection of a sample for recovery of Enterobius vermicularis includes collecting: A. a 24-hour urine collection B. a first morning tool collection with proper preservative C. a scotch tape preparation from the perianal region D. peripheral blood from a finger

Correct Answer: C

Pus from a draining fistula on a foot was submitted for culture. Gross examination of the specimen revealed the presence of a small (0.8 mm in diameter), yellowish, oval granule. Direct microscopic examination of the crushed granule showed hyphae 3-4 um in diameter and presence of chlamydospores at the periphery. After 2 days a cottony, white mold was seen that turned gray with a gray to black reverse after a few days. When viewed microscopically, moderately large hyaline septate hyphae with long or short conidiophores, each with a single moderately large hyaline septate hyphae with long or short conidiophores, w\each with a single pear-shaped conidium, 5-7 x 8-10 um, were seen. The most likely identification is: A. Exophiala jeanselmei B. Fonsecaea pedrosoi C. Pseudallescheria boydii D. Cladosporium carrionii

Correct Answer: C

Quality control results for disk diffusion susceptibility tests yield the following results: aminoglycoside zones too small and penicillin zones too large. This is most likely due to the: A. inoculum being too heavy B. inoculum being too light C. pH of Mueller-Hinton agar being too low D. calcium and magnesium concentration in the agar being too high

Correct Answer: C

Refer to the following image: See BOC pg 342 Pic 1 The egg depicted above is most likely to be found in children suffering from: A. diarrhea B. constipation C. perianal itching D. stomach pain

Correct Answer: C

SPS is used as an anticoagulant for blood cultures because it: A. inactivates penicillin and cephalosporins B. prevents clumping of red cells C. inactivates neutrophils and components of serum complement D. facilitates growth of anaerobes

Correct Answer: C

Salmonella enteritidis is isolated form multiple blood cultures in a patient with fever. Susceptibility results are as follows: -ampicllin-susceptible -ceftriaxone-susceptible -ciprofloxacin-susceptible -trimethoprim/sulfamethoxazole-resistant What is the next best step? A. report all of the susceptibility testing results with no changes B. perform a beta-lactamase test on the isolate before reporting the ampicillin as susceptible C. test the isolate against nalidixic acid and if resistant report the ciprofloxacin as resistant D. report gentamicin since the trimethoprim/sulfamethoxazole is resistant

Correct Answer: C

Susceptibility testing performed on quality control organism using a new media lot number yielded zone sizes that were too large for all antibiotics tested. The testing was repeated using media from a previously used lot number, and all zone sizes were acceptable. Which of the following best explains the unacceptable zone sizes? A. the antibiotic disks were not stored with the proper desiccant B. the depth of the media was too thick C. the depth of the media was too thin D. the antibiotic disks were not properly applied to the media

Correct Answer: C

Test for beta-lactamase production in Haemophilus influenzae: A. are not commercially available B. include test that measure a change to an alkaline pH C. should be performed on all blood and CSF isolates D. are not valid for any other bacterial species

Correct Answer: C

The Epstein-Barr virus is associated with which of the following? A. chickenpox B. Hodgkin lymphoma C. Burkitt lymphoma D. smallpox

Correct Answer: C

The Gram stain from a blood culture shows gram-positive cocci in chains. No growth occurs on blood agar plates incubated both aerobically an anaerobically. Additional testing should be done to detect the presence of: A. Staphylococcus saprophyticus B. Aerococcus urinae C. Abiotrophia defectiva D. Streptococcus pneumoniae

Correct Answer: C

The ability to detect oxacillin-resistant Staphylococcus aureus may be enhanced by: A. shortening incubation of standard susceptibility plates B. incubating susceptibility plates at 39-41 C C. using Mueller-Hinton broth with 2% NaCl D. adjusting inoculum to 0.1 McFarland before inoculating susceptibility plates

Correct Answer: C

The best medium for culture of Mycobacterium tuberculosis is: A. Bordet-Gengou agar B. Loefffler medium C. Lowenstien-Jensen medium D. cystine blood agar

Correct Answer: C

The disease-producing capacity of Mycobacterium tuberculosis depends primarily upon: A. production of exotoxin B. production of endotoxin C. capacity to withstand intracellular digestion by macrophages D. lack of susceptibility to the myeloperoxidase system

Correct Answer: C

The following growth result were observed on media inoculated with a foot abscess aspirate and incubated in 3%-5% CO2 -SBA: 2+ large gray colonies -PEA: no growth -chocolate: 3+ large gray colonies -MacConkey: 3+ lactose fermenters -trypticase soy broth: gram-negative bacilli and gram-positive bacilli Biochemicals were set up on the colonies form the MacConkey agar plate. What should the microbiologist do next? A. set up biochemicals on the colonies from SBA B. send out final report to the physician after biochemical are interpreted C. subculture TSB to SBA aerobic and SBA anaerobic D. test colonies on chocolate agar with hemin and NAD

Correct Answer: C

The following results were obtained form a culture of unknown origin: -Gram stai: gram-negative diplococci -indophenol oxidase: positive -glucose: positive -maltose: negative -sucrose: negative The most likely source of the specimen would be the: A. respiratory tract B. blood C. genitourinary tract D. cerebrospinal fluid

Correct Answer: C

The morphological characteristics of a yeast grown in rabbit plasma are shown in the image: See BOC pa 323 The most likely identification of this yeast is: A. Candida tropicalis B. Candida krusei C. Candida albicans D. Candida glabrata

Correct Answer: C

The most critical distinction between Staphylococcus aureus and other Staphylococcus is: A. phosphates reaction B. DNA production C. coagulase production D. hemolysis

Correct Answer: C

The most sensitive test for the initial diagnosis of cryptococcal disease is: A. India ink B. Gram stain C. cryptococcal antigen D. Giemsa stain

Correct Answer: C

The nitrate test for mycobacteria can be performed with a reagent impregnated paper strip or by the use of standard reagents. In order to quality control the test properly, which of the following should be used for a positive control? A. Mycobacterium bovis B. Mycobacterium gordonae C. Mycobacterium tuberculosis D. Mycobacterium intracellulare

Correct Answer: C

The optimal wound specimen for culture of anaerobic organisms should be: A. a swab of lesion obtained before administration of antibiotics B. a swab of lesion obtained after administration of antibiotics C. a syringe filled with pus, obtained before administration of antibiotics D. a syringe filled with pus, obtained after administration of antibiotics

Correct Answer: C

The optochin (ethylhydrocupreine hydrochloride) disk is used for the identification of: A. Haemophilus influenzae B. group A beta-hemolytic streptococcci C. Streptococcus pneumoniae D. alpha-hemolytic streptococci

Correct Answer: C

The orgamism most commonly associated with neonatal purulent meningitis is: A. Neisseria meningitidis B. Streptococcus pneumoniae C. group B streptococci D. Haemophilus influenzae

Correct Answer: C

The porphyrin test was devised to detect strains of Haemophilus capable of: A. ampicillin degradation B. capsule production C. synthesis of hemin D. chloramphenicol resistance

Correct Answer: C

The primary isolation of Neisseria gonorrhoeae requires: A. anaerobic conditions B. starch media C. carbon dioxide D. blood agar

Correct Answer: C

The proper blood-to-broth ratio for blood cultures to reduce the antibacterial effect of serum in adults is: A. 1:2 B. 1:3 C. 1:10 D. 1:30

Correct Answer: C

The stock cultures needed for quality control testing of oxidase production are: A. Escherichia coli/ Klebsiella pneumoniae B. Salmonella typhimurium/ Escherichia coli C. Escherichia coli/ Pseudomonas aeruginosa D. Proteus mirabilis/ Escherichia coli

Correct Answer: C

When stool examination is negative, the preferred specimen for the diagnosis of paragonimiasis is: A. bile drainage B. duodenal aspirate C. sputum D. rectal biopsy

Correct Answer: C

Which compound, detected by Lugol iodine, is used in the nonimmunologic detection of Chlamydia trachomatis in cell culture? A. DNA B. RNA C. glycogen D. DNA polymerase

Correct Answer: C

Which of the following combinations is useful for confirming the presence of extended spectrum beta-lactamases in E. coli? A. ampicillin + cefepime B. cefoxitin + penicillin C. ceftazidime + clavulanic acid D. cefpodoxime + cefotaxime

Correct Answer: C

Which of the following is the most reliable test to differentiate Neisseria lactaminca from Neisseria meningitidis? A. acid from maltose B. growth on modified Thayer-Martin agar C. lactose degradation D. nitrite reduction to nitrogen gas

Correct Answer: C

Which of the following is the most useful morphological feature identifying the mycelial phase of Histoplasma capsulatum? A. arthrospores every other cell B. 2-5 um microspores C. 8-14 um tuberculate macroconidia D. 5-7 um nonseptate macroconidia

Correct Answer: C

Which of the following organism is, to date, considered universally susceptible to penicillin: A. Haemophilus influenzae B. Neisseria gonorrhoeae C. Streptococcus pyogenes D. Corynebacterium diphtheriae

Correct Answer: C

Which of the following sets of organisms may exhibit a brick red fluorescence? A. Porphyromonas asaccharolytica an dClostridium ramosum B. Clostridium difficile and Fusobacterium sp C. Veillonella parvula and Prevotella melaninogenica D. Fusobacterium sp and Veillonella parvula

Correct Answer: C

Which of the following specimens is considered to be the most sensitive for the recovery of Brucella in cases of chronic infection? A. blood B. urine C. bone marrow D. lymph node

Correct Answer: C

Which of the following statements concerning the germ tube test is true? A. using a heavy inoculum enhances the rapid production of germ tubes B. germ tubes should be read after 2 hours incubation at 25C C. Candida albicans and Candida tropicalis can be used as positive and negative controls, respectively D. serum will be stable for 1 year if stored at 4C prior to use

Correct Answer: C

Which of the following would best differentiate Streptococcus agalactiae from Streptococcus pyogenes? A. ability to grow in sodium azide broth B. a positive bile-esculin reaction C. hydrolysis of sodium hippurate D. beta-hemolysis on sheep blood agar

Correct Answer: C

A 25-year-old man who had recently worked as a steward on a transoceanic grain ship presented to the emergency room with high fever, diarrhea and prostration. Axillary lymph nodes were hemorrhagic and enlarged. A Wayson stain of the aspirate showed bacilli that were bipolar, resembling safety pins. The most likely identification of this organism is: A. Brucella melitensis B. Streptobacillus monliformis C. Spirillum minus D. Yesinia pestis

Correct Answer: D

A Gram stain from a swab of a hand wound reveals: -moderate neutrophils -no squamous epithelial cells -moderate gram-positive cocci in chains -moderate large gram-negative bacilli Select the appropriate media that will selectively isolate each organism. A. KV-laked agar, Thayer-Martin B. sheep blood, MacConkey C. Columbia CNA, chocolate D. Columbia CNA, MacConkey

Correct Answer: D

A Gram stain of organisms on Loeffler agar showed pleomorphic gram-positive bacilli. The organism should be subcultured to: A. blood B. chocolate C. MacConkey D. postassium tellurite

Correct Answer: D

A Staphylococcus aureus isolate has an MIC of 4 ug/mL to oxacillin. There is uncertainty as to whether this represents an oxacillin (heteroresistant) resistant strain or hyperproducer of beta-lactamase. Strain; Oxacillin; Amoxicillin-clavulanic acid -Strain A: sus;sus -Strain B: sus; res -Stain C: res; sus -Strain D: res; res Based on the above results for oxacillin and amoxicillin-clavulanic acid, which strain is heteroresistant? A. stain A B. strain B C. strain C D. strain D

Correct Answer: D

A TSI tube inoculated with an organism gave the following reactions: -alkaline slant, acid butt, no H2S, no gas produced This organism is most likely: A. Yersinia enterocolitica B. Salmonella typhi C. Salmonella enteritidis D. Shigella dysenteriae

Correct Answer: D

A batch of trichrome-stained slides for ova and parasite examination contains numerous minute crystals, which totally obscure the microscopic field. Which of the following measures is the most appropriate remedial action? A. change the Schaudinn fixative, remover coverslips and restain B. change the acid alcohol and restain C. remove coverslips and remount using fresh Permount or similar medium D. change the iodine alcohol solution to obtain a strong tea-colored solution, restain

Correct Answer: D

A beta-hemolytic, catalase-positive, gram-positive coccus is coagulase negative by the slide coagulase test. Which of the following is the most appropriate action in identification of this organism? A. report a coagulase-negative Staphylococcus B. report a coagulase-negative Staphylococcus aureus C. reconfirm the hemolytic reaction of a fresh 24-hour culture D. do a tube coagulase test to confirm the slide test

Correct Answer: D

A branching gram-positive, partially acid-fast organism is isolated from a bronchial washing on a 63-year-old woman receiving chemotherapy. The organism does not hydrolyze casein, tyrosine or xanthine. The most likely identification is: A. Actinomadura madurae B. Nocardia caviae C. Streptomyces somaliensis D. Nocardia asteroides

Correct Answer: D

A bronchial washing is processed for acid-fast bacilli. Which of the following precautions should be taken in order to prevent infection of laboratory personnel? A. add an equal amount of NALC to the specimen B. process all specimens under ultraviolet light C. centrifuge specimen only after the addition of preservative D. process all specimens in a biological safety hood

Correct Answer: D

A cell culture line used for the recovery of Chlamydia trachomatis from clinical specimens is: A. HeLa 229 B. Hep-2 C. BHK-21 D. McCoy

Correct Answer: D

A college student attended a beach party where raw oyster and other shellfish were consumed. The next day, he had symptoms of septicemia. The blood cultures grew gram-negative bacilli with the following characteristics: -oxidase: positive -MacConkey agar: pink colonies -O/129 (150 ug): susceptible The most likely organism is: A. Aeromonas hydrophila B. Pseudomonas putida C. Serratia marcescens D. Vibrio vulnificus

Correct Answer: D

A community hospital microbiology laboratory is processing significant numbers of stool cultures because of an outbreak of diarrhea following heavy rains and flooding in the county. A media that should be incorporated in the plating protocol is: A. colistin nalidixic acid for Listeria B. MacConkey agar with sorbitol for Campylobacter C. mannitol salt agar for Enterococcus species D. thiosulfate citrate bile salts sucrose for Vibrio species

Correct Answer: D

A culture from an infected dog bite on a small boy's finger yielded a small, gram-negative coccobacillus that was smooth, raised and beta-hemolytic on blood agar. The isolate grew on MacConkey agar, forming colorless colonies. The organism was motile, catalase positive, oxidase positive, reduced nitrate, and was urease positive within 4 hours. No carbohydrates were fermented . The most likely identification of this isolate is: A. Brucella canis B. Yersinia pestis C. Francisella tularensis D. Bordetella bronchiseptica

Correct Answer: D

A first morning sputum is received for acid fast culture. The specimen is centrifuged, and the sediment is inoculated on 2 Lowenstein-Jensen slants, which are incubated at 35C in 5%-10% CO2. After 1 week, the slants show abundant growth over the entire surface. Stains reveal gram-negative bacilli. To avoid this problem: A. utilize a medium that inhibits bacterial growth B. add sodium hypochlorite to the sediment before inoculation C. incubate the tubes at room temperature to retard bacterial growth D. decontaminate the specimen with sodium hydroxide

Correct Answer: D

A first morning sputum is received for culture of mycobacteria. It is digested and concentrated by the N-acetyl-L-cysteine alkali method. Two Lowenstein-Jensen slants are incubated in the dark at 35C with 5%-10% CO2. The smears reveal acid-fast bacilli, and after 7 days no growth appears on the slants. The best explanation is: A. improper specimen submitted B. incorrect concentration procedure C. exposure to CO2 prevents growth D. cultures held for insufficient length of time

Correct Answer: D

A formed stool is recived in the laboratory at 3 AM for ova and parasite exam. The night shift technologist is certain that the workload will prevent examination of the specimen until 6 AM when the next shift arrives. The technologist should: A. request that a new specimen be collected after 6 AM B. perform a zinc sulfate floatation procedure for eggs and hold the remaining specimen at room temperature C. examine a direct prep for trophozoites and freeze the remaining specimen D. preserve the specimen in formalin until it can be examined

Correct Answer: D

A gram-positive coccus isolated form a blood culture has the following characteristics: -optochin susceptibility: negative -bacitracin (0.04 U) susceptibility: negative -bile esculin hydrolysis: negative -hippurate hydrolysis: positive -catalase: negative This organism is most likely: A. Staphylococcus aureus B. Streptococcus pneumoniae C. Streptococcus pyogenes D. Streptococcus agalactiae

Correct Answer: D

A jaundiced 7-year-old boy, with a history of playing in a pond in a rat-infested are, has a urine specimen submitted for a direct darkfield examination. Several spiral organisms are seen. Several spiral organisms are seen. Which of the following organisms would most likely be responsible for the patient's condition? A. Spirillum minus B. Streptobacillus moniliformis C. Listeria monocytogenes D. Leptospira interrogans

Correct Answer: D

A laboratory aid receives a bronchoscopy sample with the request for culture of Legionella. The assistant asks a microbiologist for direction on plating protocol. The correct response from the microbiologist is: A. culture on thiosulfate citrate bile salt media B. incubate the culture media anaerobically C. reject the specimen and request a sputum sample D. culture on buffered charcoal yeast extract agar with antibiotics

Correct Answer: D

A nonchromogen that grows best at 42C and is highly resistant to antibiotics is: A. Mycobacterium chelonae B. Mycobacterium marinum C. Mycobacterium tuberculosis D. Mycobacterium xenopi

Correct Answer: D

A nonfermenting gram-negative bacillus is isolated form a wound. The nitrate and oxidase are strongly positive. The growth on sheep blood agar has a grape-like odor. The organism is: A. Burkholderia cepacia B. Moraxella lacunata C. Chryseobacterium (Flavobacterium) meningosepticum D. Pseudomonas aeruginosa

Correct Answer: D

A patient with a nosocomial pneumonia has a sputum Gram stain that shows many neutrophils and numerous small gram-negative coccobacilli. The organism grew in 24 hours as a mucoid, hemolytic colony on blood agar, and a colorless colony on a MacConkey agar. The organism had the following characteristics: -oxidase: neg -catalase: pos -nitrate: neg -ONPG: neg -ornithine decarboxylase: neg -lysine decarboxylase: neg The organism is: A. Stenotrophomonas maltophilia B. Alcalignenes faecalis C. Moraxella lacunata D. Acinetobacter baumannii

Correct Answer: D

A sheep blood agar plate inoculate with 0.001 mL, of urine grows 70 colonies of Staphylococcus aureus. How many colony forming units per mL of urine should be reported? A. 70 B. 700 C. 7,000 D. 70,000

Correct Answer: D

A sputum specimen is recieved for culture and Gram stain. The Gram stained smear from this specimen is seen in the image (total magnification 100X): See BOC pg 288 The technologist's best course of action would be to: A. inoculate appropriate media and incubate anaerobically B. inoculate appropriate media and incubate aerobically C. call the physician and notify him of this "life-threatening" situation D. call the patient care area and request a new specimen

Correct Answer: D

A urine culture from a patient with a urinary tract infection yields a yeast with the following characteristics: -failure to produce germ tubes -hyphae not formed on cornmeal agar -urease-negative -assimilates trehalose The most likely identification is: A. Saccharomyces cerevisiae B. Crytococcus laurentii C. Candida pseudotropicalis D. Candida glabrata

Correct Answer: D

A vaginal smear is submitted for a Gram stain for Neisseria gonorrheae. The technologist finds the following results on the Gram stain: -many white blood cells -few epithelial cells -many gram-positive bacilli -few gram-negative diplococci -few gram-positive cocci in chains The technologist should: A. report out smear positive for gonorrhea B. report out smear negative for gonorrhea C. request a new specimen due to number of white blood cells D. not read or report a Gram stain on a vaginal specimen

Correct Answer: D

A yeast isolate from a CSF specimen produced the following results: -India ink: no encapsulated yeast cells -Cryptococcal antigen: negative -Urea: negative -Germ tube: negative What should the technologist do next to identify this organism? A. inoculate bird seed agar B. ascospore stain C. cycloheximide susceptibility D. carbohydrate assimilation

Correct Answer: D

All species of the genus Neisseria have the enzyme to oxidize: A. naphthylamine B. dimenthylaminobenzaldehyde C. glucopyranoside D. tetramethyl-phenylenediamine

Correct Answer: D

An aerobic, gram-negative coccobacillus was isolated on Bordet-Gengou agar from a nasopharyngeal swab 48 hours after culture from a 6-month-old infant with suspected pertussis. The organism exhibited the following characteristics: -MacConkey agar: no growth -urea: negative at 4 hours, positive at 24 hours -oxidase: negative -catalase: positive The most probable identification of this isolate is: A. Moraxella lacunata B. Pasteurella ureae C. Bordetella pertussis D. Bordetella parapertussis

Correct Answer: D

An aspirate of a deep wound was plated on blood agar plates and incubated aerobically and anaerobically. At 24 hours there was growth on both plates. This indicates that the organism is a(n): A. nonfermenter B. obligate anaerobe C. aerobe D. facultative anaerobe

Correct Answer: D

An expectorated sputum is sent to the laboratory for culture from a patient with respiratory distress. The Gram stain of the specimen shows many squamous epithelial cells (>25/lpf) and rare neutrophils. The microscopic appearance of the organisms present include: -moderate gram-positive cocci in chains and diplococci -moderate gram-negative diplococci -moderate palisading gram-positive bacilli all in moderate amounts This Gram stain is most indicative of: A. a pneumococcal pneumonia B. an anaerobic infection C. an Haemophilus pneumonia D. oropharyngeal flora

Correct Answer: D

An improtant cause of acute exudative pharyngitis is: A. Staphylococcus aureus (beta-hemolytic) B. Streptococcus pneumoniae C. Streptococcus agalactiae D. Streptococcus pyogenes

Correct Answer: D

An isolate of an unknown beta-hemolytic Streptococcus is streaked perpendicular to a streak of beta-lysin-producing Staphylococcus aureus. After incubation a zone of arrowhead hemolysis is noted at the interface of the 2 streaks. What is the name of the test and the presumptive identification of the unknown Streptococcus? A. hippurate hydrolysis and S agalactiae B. CAMP test and S pyogenes C. hippurate hydrolysis and S pyogenes D. CAMP teset and S agalactiae

Correct Answer: D

An urethral swab obtained form a man with an urethral exudate was plated directly on chocolate agar and modified Thayer-Martin agar, and a Gram stain was made. The Gram stain showed gram-negative diplococci. The culture plates were incubated at 35C, but had not growth at 48 hours. The most likely failure for organism growth is that the: A. wrong media were used B. Gram stain was misread C. organism only grows at room temperature D. organism requires CO2 for growth

Correct Answer: D

Antifungal susceptibility test for yeasts are: A. performed routinely B. highly reproducible C. not clinically relevant D. more useful in identifying resistant strains

Correct Answer: D

Artifacts found in a stool specimen that can be confused with ova or cysts are: A. partially digested meat fibers B. degenerated cells from the gastrointestinal mucosa C. dried chemical crystals D. pollen grains

Correct Answer: D

Biochemical reactions of an organisms are consistent with Shigella. A suspension is tested in antiserum without resulting agglutination. However, after 15 minutes of boiling, agglutination occurs in group D antisera. The Shigella species is: A. dysenteriae B. flexneri C. boydii D. sonnei

Correct Answer: D

Characteristics necessary for the definitive identification of Mycobacterium tuberculosis are: A. buff color, slow growth at 37C, niacin production-positive, nitrate reduction-negative B. rough colony, slow growth at 37C, nonpigmented C. rough, nonpigmented colony, cording positive, niacin production-negative, catalase-negative at pH 7/68C D. rough, nonpigmented colony, slow growth at 37C, niacin production-positive, nitrate reduction-positive

Correct Answer: D

Chocolate agar base containing vancomycin, colistin, anisomycin, and trimethoprim is also known as: A. EMB agar B. modified Thayer-Martin agar C. Columbia CNA agar D. Martin Lewis agar

Correct Answer: D

Definitive identification of Neisseria gonorrhoeae is made with the: A. Gram stain B. oxidase test C. degradation of amino acids D. hydrolysis of carbohydrates

Correct Answer: D

Differentiating tests that will separate Burkholderia from Stenotrophomonas include: A. Gram stain reaction B. growth on MacConkey agar C. glucose fermentation D. oxidase

Correct Answer: D

Differentiation of Mycobacterium avium from Mycobacterium intracellulare can be accomplished by: A. nitrate reduction test B. Tween hydrolysis test C. resistance to 10 ug thiophene-2-carboxylic acid hydrazide (TCH) D. DNA probe

Correct Answer: D

Enzymatic drug modification is a mechanism of resistance for which antimicrobial? A. levofloxacin B. sulfamethoxazole C. vancomycin D. gentamicin

Correct Answer: D

Gram stain of a thigh wound showed many gram-positive spore-froming bacilli. The specimen was placed on brain heart infusion blood agar and incubated aerobically at 35C for 3 days. At the end of that time, the plates showed no growth. The most likely explanation is that some of the specimen should have been incubated: A. on chocolate agar B. for 5 days C. under 5% CO2 D. anaerobically

Correct Answer: D

Haemophilus influenzae becomes resistant to ampicillin when the organism produces a(n): A. capsule of polysaccharide material B. affinity for the beta-lactam ring of the ampicillin C. porphobilinogen D. beta-lactamase enzyme

Correct Answer: D

If present, a characteristic that is helpful in separating Pseudomonas aeruginosa form other members of the Pseudomonas family is: A. a positive test for cytochrome oxidase B. oxidative metabolism in the OF test C. production of fluorescein pigment D. growth at 42C

Correct Answer: D

In reviewing the number of Mycobacterium isolates for the current year, it was noted that there were 76% fewer isolates than the previous year (115 vs 28). The technologist in charge of the area has documented that the quality control of media, reagents and stains has been acceptable and there has been no gross contamination of the cultures noted. The most appropriate course of action to pursue would be: A. stop use of commercial media and produce in-house B. change to different formulation of egg and agar based media C. change over to the Bactec system for isolation of Mycobacterium D. review the digestion and decontamination procedure

Correct Answer: D

It is important to differentiate between Enterococcus and group D streptococci because: A. viridans streptococci are often confused with enterococci B. several enterococci cause severe puerperal sepsis C. group D streptococci are avirulent D. enterococci often show more antibiotic resistance tan group D streptococci

Correct Answer: D

Lab workers should always work under a biological safety hood when working with cultures of: A. Streptococcus pyogenes B. Staphylococcus aureus C. Candida albicans D. Coccidioides immitis

Correct Answer: D

Listeria can be confused with some streptococci because of its hemolysis and because it is: A. nonmotile B. catalase negative C. oxidase positive D. esculin positive

Correct Answer: D

Many fungal infections are transmitted to man via inhalation of infectious structures. Which of the following is usually contracted in this manner? A. Sprothrix scenckii B. Trichophyton rubrum C. Malassezia furfur D. Histoplasma capsulatum

Correct Answer: D

Members of the family Enterobacteiaceae share with one of the following characteristics? A. produce cytochrome oxidase B. ferment lactose C. produce beta-hemolysis D. reduce nitrate to nitrite

Correct Answer: D

Microorganisms resembling L-forms have been isolated from the blood of patients treated with antibiotics that: A. complex with flagellar protein B. interfere with cell membrane function C. inhibit protein synthesis D. interfere with cell wall synthesis

Correct Answer: D

Middlebrook 7H10 and 7H11 media must be refrigerated in the dark, and incubated in the dark as well. If these conditions are not met, the media may prove toxic for mycobacteria because: A. carbon dioxide will be released B. growth factors will be broke down C. light destroys the ammonium sulfate D. formaldehyde may be produced

Correct Answer: D

Of the following bacteria, the most frequent cause of prosthetic heart valve infections occuring with 2-3 months after surgery is: A. Staphylococcus aureus (beta-hemolytic) B. Streptococcus pyogenes C. Staphylococcus aureus D. Staphylococcus epidermidis

Correct Answer: D

Serum samples collected from a patient with pneumonia demostrate a rising antibody titer to Legionella. A bronchoalveolar lavage (BAL) specimen from this patient had a positive antigen test for Legionella but no organisms were recovered on buffered charcoal yeast extract medium after 2 days of incubation. The best explanation is that the: A. antibody titer represents an earlier infection B. positive antigen test is a false positive C. specimen was cultured on the wrong media D. culture was not incubated long enough

Correct Answer: D

Skin scrapings obtained form the edge of a crusty wrist lesion were found to contain thick-walled, spherical yeast cells (8-15 um in diameter) that had single buds with a wide base of attachment. Microscopic examination of the room temperature isolate form this specimen would probably reveal the presence of: A. "rosette-like" clusters of pear-shaped conidia at the tips of delicate conidiophores B. thick-walled, round to pear-shaped tuberculate macroconidia C. numerous conidia along the length of hyphae in a "sleevelike" arrangement D. round or pear-shaped small conidia attached to conidiosphores of irregular lengths

Correct Answer: D

Staib medium (birdseed agar) is useful in the identification of which of the following? A. Candida albicans B. Candida glabrata C. Saccharomyces cerevisiae D. Crytococcus neoformans

Correct Answer: D

Streptococcus pneumoniae can be differentiated best from the viridans group of streptococci by: A. Gram stain B. the type of hemolysis C. colonial morphology D. bile solubility

Correct Answer: D

Susceptibility testing is performed on a Staphylococcus aureus isolate form a blood culture with the following results: -oxacillin: resistant -cefazolin: susceptible -clindamycin: susceptible -erythromycin: susceptible -trimethoprim/sulfamethoxazole: susceptible -vancomycin: susceptible What should the technologist do next? A. ceftriaxone should be reported instead of cefazolin B. clindamycin should be tested for inducible resistance prior to reporting C. the trimethoprim/ sulfamethoxazole result should be removed since all S aureus are resistant D. the cefazolin result should be changed to resistant since the oxacillin result is resistant

Correct Answer: D

The appropriate specimen for the diagnosis of mucormycosis is: A. nasal swab B. sputum C. sinus washing D. eschar biopsy

Correct Answer: D

The characteristic that is most commonly associated with the presence of strict anaerobic bacteria and can be taken as presumptive evidence of their presence in a clinical specimen is the: A. presence of a single bacterial species B. production of gas in a thioglycollate broth culture C. growth on a blood agar plate incubated in anaerobically jar D. presence of a foul, putrid odor from tissue specimens and cultures

Correct Answer: D

The etiologic agent of botulism is: A. highly motile B. non-spore-forming C. Clostridium perfringens D. an exotoxin producer

Correct Answer: D

The formation of germ tubes presumptively identifies: A. Candida tropicalis B. Candida parapsilosis C. Candida glabrata D. Candida albicans

Correct Answer: D

The function of N-acetyl-L-cysteine in the reagent for acid-fast digestion-decontamination procedure is to: A. inhibit growth of normal respiratory flora B. inhibit growth of fungi C. neutralize the sodium hydroxide D. liquefy the mucus

Correct Answer: D

The image depicts a Gram stain (final magnification 1,000X) of a knee fluid from a patient who has recently undergone knee replacement surgery: See BOC pg 293 The best interpretation of this Gram stain is: A. gram-positive cocci suggestive of Staphylococcus B. gram-positive bacilli suggestive of Corynebacterium C. gram-positive bacilli suggestive of Listeria D. gram-positive cocci suggestive of Streptococcus

Correct Answer: D

The laboratory receives a blood culture from a veterinarian who has been ill for many weeks with fevers in the afternoon and evenings, arthritis, and fatigue. The blood culture is positive after 5 days, and the organism has the following characteristics: -Gram stain: small, gram-negative coccobacilli -Sheep blood agar: growth after 48 hours with small, smooth, raised colonies What should the microbiologist do next? A. consider the growth contamination and perform another gram stain B. perform biochemical identification for HACEK organisms C. perform identification and susceptibility testing using an automated system D. take extra safety precaution for possible Brucella

Correct Answer: D

The method of choice to detect Acanthamoeba sp form corneal ulcer scrapings is: A. Novy, macNeal and Nicolle (NNN) medium B. culture on McCoy cells C. direct exam D. blood agar flooded with a 24-hour growth of E coli

Correct Answer: D

The method used for processing specimens for mycobacterial culture contaminated with Pseudomonas is: A. N-acetyl-L-cystine and NaOH B. NaOH C. zephiran-trisodium phosphate D. oxalic acid

Correct Answer: D

The microscopic structures that are most useful in the identification of dermatophytes are: A. septate and branching hyphae B. racquet and pectinate hyphae C. chlamydospores and microconidia D. macroconidia and microconidia

Correct Answer: D

The most common cause for failure of GasPak anaerobic jar to establish an adequate environment for anaerobic incubation is: A. the failure of the oxidation-reduction potential indicator system due to deterioration of methylene blue B. the failure of the packet to generate adequate H2 and/or CO2 C. condensation of water on the inner surface of the jar D. catalysts that have become inactivated after repeated use

Correct Answer: D

The most rapid method for detection of Francisella tularensis is: A. serological slide agglutination utilizing specific antiserum B. dye stained clinical specimens C. fluorescent antibody stain techniques on clinical specimens D. polymerase chain reaction

Correct Answer: D

The most sensitive substrate for the detection of beta-lactamases is: A. penicillin B. ampicillin C. cefoxitin D. nitrocefin

Correct Answer: D

The one characteristic by which an unknown Cryptococcus species can be identified as Crytococcus neoformans is: A. appearance of yellow colonies B. positive urease test C. presence of a capsule D. positive phenol oxidase test

Correct Answer: D

The optimal incubator temperture for isolation of the Campylobacter jejuni/coli group is; A. 4C B. 20C C. 25C D. 42C

Correct Answer: D

When using a control stain of Staphylococcus aureus, the technologist notices that the zone around the oxacillin disk is too small. Which of the following is the most likely explanation? A. inoculation of the plates 10 minutes after preparing th inoculum B. incubation of the Mueller-Hinton plates at 35C C. use of a 0.25 McFarland standard to prepare inoculum D. use of outdate oxacillin disks

Correct Answer: D

Which feature distinguishes Erysipelothrix rhusiopathiae from other clinically significant non-spore-forming, gram-positive, facultatively anaerobic bacilli? A. "tumbling" motility B. beta-hemolysis C. more pronounced motility at 25C than 37C D. H2S production

Correct Answer: D

Which of the following antimicrobial would be inappropriate to report on an E. coli isolated form a would culture? A. gentamicin B. ampicillin C. cefazolin D. nitrofurantoin

Correct Answer: D

Which of the following characteristics best differentiates Bordetella bronchiseptica from Alcoligenes species? A. flagellar patter B. growth at 24C C. oxidase activity D. rapid hydrolysis of urea

Correct Answer: D

Which of the following genera include anaerobic gram-negative nonsporulating bacilli? A. Brucella B. Pasteurella C. Actinomyces D. Bacteroides

Correct Answer: D

Which of the following is a growth requirement for the isolation of Leptospira? A. an atmosphere of 10A% CO2 B. an incubation temperature 4C C. 4-5 day incubation D. medium containing 10% serum plus fatty acids

Correct Answer: D

Which of the following is the best aid in the identification of Epidermophyton floccosum macroconidia? A. parallel side walls with at least 10 cells B. spindle-shaped spore with thin walls C. spindle-shaped spore, thick walls and distinct terminal knob with echinulations D. smooth walls, club-shaped

Correct Answer: D

Which of the following is the most appropriate method for collecting a urine specimen from a patient with an indwelling catheter? A. remove the catheter, cut the tip, and submit it for culture B. disconnect the catheter from the bag, and collect urine form the terminal end of the catheter C. collect urine directly from the bag D. aspirate urine aseptically from the catheter tubing

Correct Answer: D

Which of the following is the most appropriate organism and media combination? A. Legionella species-Regan Lowe B. Clostridium difficile-phenylethyl alcohol (PEA) C. Campylobacter species-charcoal yeast extract D. Yersinia entorocolitica-cefsulodin-irgasan-novobiocin (CIN)

Correct Answer: D

Which of the following may be used as a positive quality control organism for the bile esculin test? A. Staphylococcus epidermidis B. Staphylococcus aureus C. Streptococcus pyogenes D. Enterococcus faecalis

Correct Answer: D

Which of the following organisms may be mistaken for Neisseria gonorrhoeae in Gram stained smears of uterine cervix exudates? A. Lactobacillus species B. Streptococcus agalactiae C. Pseudomonas aeruginosa D. Moraxella osloensis

Correct Answer: D

Which one of the following genera is among the least biochemically reactive members of the Enterobacteriaceae? A. Proteus B. Pseudomonas C. Citrobacter D. Shigella

Correct Answer: D

Which one of the following gram-negative bacilli ferments glucose? A. Alcaligenes faecalis B. Pseudomonas cepacia C. Acinetobacer lwoffii D. Yersinia enterocolitica

Correct Answer: D