MICRO Ch. 19 quiz

Members of the family Enterobacteriaceae share which of the following characteristics? a. produce cytochrome oxidase b. ferment lactose c. produce beta hemolysis d. reduce nitrate to nitrite

d. reduce nitrate to nitrite

Biochemical reactions of an organism are consistent with Shigella. A suspension is tested in antiserum without resulting agglutination. However, after 15 mins. of boiling, agglutination occurs in group D antisera. The Shigella species is: a. dysenteriae b. flexneri c. boydii d. sonnei

d. sonnei

The shigellae lack this group of antigens A) All the above B) H C) K D) O

B) H

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

C. MacConkey agar with sorbitol

The ONPG test allows organisms to be classified as a lactose fermenter by testing for which of the following? a. permease b. Beta-galactoside c. beta-lactamase d. phosphate

b. Beta-galactoside

All of the following are categories of diarrhea-causing Escherichia coli, except a. ETEC. b. EMEC. c. EIEC. d. EPEC.

b. EMEC.

What genus has the following characteristics: urea negative, positive for lysine decarboxylase, hydrogen sulfide, and indole, and does not grow on Simmon's citrate? a. Providencia b. Edwardsiella c. Escherichia d. Morganella

b. Edwardsiella

An organism is inoculated to a TSI tube and gives the reaction "acid slant, acid butt, no H2S"? a. Salmonella spp. b. Escherichia coli c. Proteus spp. d. Pseudomonas spp.

b. Escherichia coli

The most important cause of UTIs is a. Klebsiella pneumoniae. b. Escherichia coli. c. Hafnium alvei. d. Morganella morganii.

b. Escherichia coli.

Which group of tests best differentiates Enterobacter aerogenes from Edwardsiella tarda? a. Motility, citrate, and urease b. H2S production, sucrose fermentation, indole and VP c. Lysine decarboxylase, urease, and arginine dihydrolase d. Motility, H2S production and DNase

b. H2S production, sucrose fermentation, indole and VP

A sputum culture from an alcoholic seen in the ER grows gray, mucoid, stringy colonies on SBA. The isolate grows readily on MacConkey agar and forms mucoid, dark pink colonies. The colonies yield the following test results: ONPG - positive indole - negative glucose - positive oxidase - negative citrate - positive VP - positive The organism is most likely: a. Edwardsiella tarda b. Klebsiella pneumoniae c. Escherichia coli d. Proteus vulgaris

b. Klebsiella pneumoniae

The optimal incubator temperature for isolation of the Campylobacter jejuni/coli group is: a. 4 C b. 20 C c. 25 C d. 42 C

d. 42 C

Which of the following is an Escherichia coli virulence factor that allows the bacterial cell to chelate iron? a. Cytolysins b. Shiga-like toxin c. M protein d. Aerobactin

d. Aerobactin

All of the following are clinically significant isolates of the genus Enterobacter, except a. Enterobacter cloacae. b. E. aerogenes. c. E. gergoviae. d. E. hartmanni.

d. E. hartmanni.

What are the primary antigens used in serologic grouping of salmonellae? a. Somatic A antigen and flagellar O antigens b. Capsular A antigen and somatic O antigen c. Flagellar H antigen and capsular A antigen d. Flagellar H antigen and somatic O antigen

d. Flagellar H antigen and somatic O antigen

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

d. Klebsiella pneumoniae / Escherichia coli

The stock cultures needed for quality control testing of phenylalanine deamination activity are: a. Escherichia coli / Klebsiella pneumoniae b. Salmonella typhimurium / Escherichia coli c. Escherichia coli / Pseudomonas aeruginosa d. Proteus mirabilis / Escherichia coli

d. Proteus mirabilis / Escherichia coli

Which color and pigment is associated with Serratia marcescens? a. Yellow xanthophyll b. Yellow echineone c. Orange tetraterpenoid d. Red prodigiosin

d. Red prodigiosin

Which species of Shigella is most commonly associated with diarrheal disease in the United States? a. S. dysenteriae b. S. flexneri c. S. boydii d. S. sonnei

d. S. sonnei

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

d. Serratia marcescens / Escherichia coli

Which organism is sometimes mistaken for Salmonella and will agglutinate in Salmonella polyvalent antiserum? A. C. freundii strains B. Proteus mirabilis strains C. S. sonnei strains D. E. coli

A. C. freundii strains

Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions occur with: A. E. coli B. Salmonella spp. C. Pseudomonas spp. D. Proteus spp.

A. E. coli

Which isolates of the Enterobacteriaceae family most commonly produce extended-spectrum β-lactamase (ESBL)? A. E. coli and Klebsiella pneumoniae B. Yersinia enterocolitica and Yersinia pestis C. Morganella morganii and Proteus vulgaris D. Salmonella typhi and Shigella sonnei

A. E. coli and Klebsiella pneumoniae

Deoxycholate agar (DCA) is useful for the isolation of: A. Enterobacteriaceae B. Enterococcus spp. C. Staphylococcus spp. D. Neisseria spp.

A. Enterobacteriaceae

Biochemically, the Enterobacteriaceae are gram-negative rods that: A. Ferment glucose, reduce nitrate to nitrite, and are oxidase negative B. Ferment glucose, produce indophenol oxidase, and form gas C. Ferment lactose and reduce nitrite to nitrogen gas D. Ferment lactose and produce indophenol oxidase

A. Ferment glucose, reduce nitrate to nitrite, and are oxidase negative

Which group of tests best identifies the Morganella and Proteus genera? A. Motility, urease, and phenylalanine deaminase B. Malonate, glucose fermentation, and deoxyribonuclease (DNase) C. Indole, oxidase, MR, and VP D. Indole, citrate, and urease

A. Motility, urease, and phenylalanine deaminase

Infections caused by Yersinia pestis are rare in the United States. Those cases that do occur are most frequently located in which region? A. New Mexico, Arizona, and California B. Alaska, Oregon, and Utah C. North and South Carolina and Virginia D. Ohio, Michigan, and Indiana

A. New Mexico, Arizona, and California

Three blood cultures taken from a 30-year-old cancer patient receiving chemotherapy and admitted with a urinary tract infection grew lactose-negative, motile, gram-negative rods prior to antibiotic therapy. Given the following biochemical reactions, which is the most likely organism? H2S (TSI) = + Indole = + MR = + VP = Neg Citrate = Neg Urease = + DNase = + Phenylalanine deaminase = + Gelatin hydrolysis = + Ornithine decarboxylase = Neg A. Proteus vulgaris B. Proteus mirabilis C. Serratia marcescens D. Klebsiella pneumoniae

A. Proteus vulgaris

A bloody stool cultured from a 26-year-old woman after 3 days of severe diarrhea showed the following results at 48 hours after being plated on the following media: MacConkey agar: little normal flora with many non-lactose-fermenting colonies Hektoen enteric agar: many blue-green colonies Campylobacter blood agar and C. difficile agar: no growth Clear colonies (from MacConkey agar) tested negative for oxidase, indole, urease, motility, and H2S The most likely identification is: A. Shigella spp. B. Salmonella spp. C. Proteus sp D. E. coli

A. Shigella spp.

Which genera of Enterobacteriaceae are usually nonmotile at 36°C? A. Shigella, Klebsiella, and Yersinia B. Escherichia, Edwardsiella, and Enterobacter C. Proteus, Providencia, and Salmonella D. Serratia, Morganella, and Hafnia

A. Shigella, Klebsiella, and Yersinia

An isolate of E. coli recovered from the stool of a patient with severe bloody diarrhea should be tested for which sugar before sending it to a reference laboratory for serotyping? A. Sorbitol (fermentation) B. Mannitol (oxidation) C. Raffinose (fermentation) D. Sucrose (fermentation)

A. Sorbitol (fermentation)

In the test for urease production, ammonia reacts to form which product? A. Ammonium citrate B. Ammonium carbonate C. Ammonium oxalate D. Ammonium nitrate

B. Ammonium carbonate

Select the medium best suited for the recovery of Yersinia enterocolitica from a patient with gastroenteritis. A. Hektoen agar B. Cefsulodin-Irgasan-Novobiocin (CIN) agar C. Blood agar D. Eosinmethylene blue agar

B. Cefsulodin-Irgasan-Novobiocin (CIN) agar

Which of the following organisms is often confused with the Salmonella species biochemically and on plated media? A. E. coli B. Citrobacter freundii C. Enterobacter cloacae D. Shigella dysenteriae

B. Citrobacter freundii

The Shiga-like toxin (verotoxin) is produced mainly by which Enterobacteriaceae? A. Klebsiella pneumoniae B. E. coli C. Salmonella typhimurium D. Enterobacter cloacae

B. E. coli

Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric pathogens? A. Enterobacter, Klebsiella, Providencia, and Proteus B. Escherichia, Salmonella, Shigella, and Yersinia C. Pseudomonas, Moraxella, Acinetobacter, and Aeromonas D. Enterobacter, Citrobacter, and Morganella

B. Escherichia, Salmonella, Shigella, and Yersinia

Which of the following tests best differentiates Shigella species from E. coli? A. Hydrogen sulfide, VP, citrate, and urease B. Lactose, indole, ONPG, and motility C. Hydrogen sulfide, MR, citrate, and urease D. Gas, citrate, and VP

B. Lactose, indole, ONPG, and motility

A gram-negative rod is recovered from a catheterized urine sample from a nursing home patient. The lactose-negative isolate tested positive for indole, urease, ornithine decarboxylase, and phenylalanine deaminase and negative for H2S. The most probable identification is: A. Edwardsiella spp. B. Morganella spp. C. Ewingella spp. D. Shigella spp.

B. Morganella spp.

Which of the following organisms, found in normal fecal flora, may be mistaken biochemically for the genus Yersinia? A. Klebsiella spp. B. Proteus spp. C. E. coli D. Enterobacter spp.

B. Proteus spp.

A leg-wound culture from a hospitalized 70-year-old diabetic man grew motile, lactose-negative colonies on MacConkey agar. Given the following biochemical reactions at 24 hours, what is the most probable organism? H2S (TSI) = Neg Indole = Neg MR = Neg VP = + DNase = + Citrate = + Urease = Neg Phenylalanine deaminase = Neg Ornithine and lysine decarboxylase = + Arginine decarboxylase = Neg Gelatin hydrolysis = + A. Proteus vulgaris B. Serratia marcescens C. Proteus mirabilis D. Enterobacter cloacae

B. Serratia marcescens

The ortho-nitrophenyl-β-galactopyranoside (ONPG) test is most useful when differentiating: A. Salmonella spp. from Pseudomonas spp. B. Shigella spp. from some strains of Escherichia coli C. Klebsiella spp. from Enterobacter spp. D. Proteus vulgaris from Salmonella spp.

B. Shigella spp. from some strains of Escherichia coli

Which agar that is used for routine stool cultures is the medium of choice for the isolation of Yersinia strains from stool specimens? A. Salmonella-Shigella agar B. Hektoen enteric agar C. MacConkey agar D. CNA agar

C. MacConkey agar

A 6-year-old female patient was admitted to the hospital following 2 days of severe diarrhea. Cultures from three consecutive stool samples contained blood and mucus. Patient history revealed a hamburger lunch at a fast-food restaurant 3 days earlier. Which pathogen is most likely responsible for the following results? Growth on: XLD agar = yellow colonies HE agar = yellow colonies Mac agar = light pink and dark pink colonies Mac with sorbitol agar - few dark pink and many colorless colonies A. Salmonella spp. B. Shigella spp. C. E. coli O157:H7 D. Yersinia enterocolitica

C. E. coli O157:H7

Xylose lysine deoxycholate (XLD) agar is a highly selective medium used for the recovery of which bacteria? A. Staphylococcus spp. from normal flora B. Yersinia spp. that do not grow on Hektoen agar C. Enterobacteriaceae from gastrointestinal specimens D. Streptococcus spp. from stool cultures

C. Enterobacteriaceae from gastrointestinal specimens

Putrescine is an alkaline amine product of which bacterial enzyme? A. Arginine decarboxylase B. Phenylalanine deaminase C. Ornithine decarboxylase D. Lysine decarboxylase

C. Ornithine decarboxylase

Lysine iron agar (LIA) showing a purple slant and a blackened butt indicates: A. E. coli B. Citrobacter spp. C. Salmonella spp. D. Proteus spp.

C. Salmonella spp.

The malonate test is most useful in differentiating which members of the Enterobacteriaceae? A. Shigella B. Proteus C. Salmonella subgroups 2, 3 (the former Arizona) D. Serratia

C. Salmonella subgroups 2, 3 (the former Arizona)

Three consecutive stool cultures from a 25-year-old male patient produced scant normal fecal flora on MacConkey and Hektoen agars. However, colonies on CIN agar (cefsulodin-irgasan-novobiocin) displayed "bulls-eye" colonies after 48 hours incubation. The patient had been suffering from enterocolitis with fever, diarrhea, and abdominal pain for 2 days. What is the most likely identification of this gram-negative rod? A. E. coli B. Proteus mirabilis C. Yersinia enterocolitica D. Klebsiella pneumoniae

C. Yersinia enterocolitica

Plesiomonas shigelloides is different from most Enterobacteriaceae in that it A) Does not reduce nitrate or grow in the presence of oxygen B) Is resistant to agent to O/129 C) Form a capsule or ferment any sugars D) Does not produce gas from glucose and is oxidase positive

D) Does not produce gas from glucose and is oxidase positive

Providencia alcalifaciens is most commonly found in A) Purulent vaginal discharge B) Catheter associated urinary tract infections C) Burns D) Feces of children with diarrhea

D) Feces of children with diarrhea

Which statement is true of Yersinia pestis? A) It is a gram variable bacillus that grows best at 37 degrees B) It is a long, chaining gram negative bacillus that grows best at 4 degrees C) It is a large, plump, bacillus that is motile at 25 degrees, but not nonmotile at 35 degrees D) It is a bipolar staining gram negative bacillus that grows best at 25-30 degrees

D) It is a bipolar staining gram negative bacillus that grows best at 25-30 degrees

Which set of tests would help differentiate between proteus vulgaris, and proteus mirabilia A) Lactose fermentation and urea B) H2S production and sucrose fermentation C) Nitrate and oxidase D) indole and irnithine decarboylase

D) indole and irnithine decarboylase

Which agar that is used for routine stool cultures is the medium of choice for the isolation of Yersinia strains from stool specimens? A. Salmonella-Shigella agar B. Hektoen enteric agar C. MacConkey agar D. CIN agar

D. CIN agar

Four blood cultures were taken over a 24-hour period from a 20-year-old woman with severe diarrhea. The cultures grew motile (room temperature), gram-negative rods. A urine specimen obtained by catheterization also showed gram-negative rods, 100,000 col/mL. Given the following results, which is the most likely organism? TSI = A/A gas Indole = + VP = Neg MR = + H2S = Neg Citrate = Neg Urease = Neg Lysine decarboxylase = + Phenylalanine deaminase = Neg A. Proteus vulgaris B. Salmonella typhi C. Yersinia enterocolitica D. E. coli

D. E. coli

Which of the following organisms are generally positive for β-galactosidase? A. Salmonella spp. B. Shigella spp. C. Proteus spp. D. E. coli

D. E. coli

Which single test best separates Klebsiella oxytoca from K. pneumoniae? A. Urease B. Sucrose C. Citrate D. Indole

D. Indole

Which group of tests, along with colonial morphology on primary media, aids most in the rapid identification of the Enterobacteriaceae? A. MR and VP, urease, and blood agar plate B. Phenylalanine deaminase, urease, and CDC agar plate C. Bacitracin, β-lactamase, and MacConkey agar plate D. Indole, oxidase, MacConkey, and blood agar plates

D. Indole, oxidase, MacConkey, and blood agar plates

Direct spread of pneumonic plague disease occurs by which route? A. Fecal-oral route B. Rat bite C. Ingestion of contaminated tissue D. Inhalation of contaminated airborne droplets

D. Inhalation of contaminated airborne droplets

A leg culture from a nursing home patient grew gram-negative rods on MacConkey agar as pink to dark pink oxidase-negative colonies. Given the following results, which is the most likely organism? TSI = A/A Indole = Neg MR = Neg VP = + Citrate = + H2S = Neg Urease = + Motility = Neg Antibiotic susceptibility: resistant to carbenicillin and ampicillin A. Serratia marcescens B. Proteus vulgaris C. Enterobacter cloacae D. Klebsiella pneumoniae

D. Klebsiella pneumoniae

Members of the genus Cedecea are best differentiated from Serratia spp. by which test result? A. Positive motility B. Positive urease C. Positive phenylalanine deaminase D. Negative DNase

D. Negative DNase

In the Kauffmann-White schema, the combined antigens used for serological identification of the Salmonella spp. are: A. O antigens B. H antigens C. Vi and H antigens D. O, Vi, and H antigens

D. O, Vi, and H antigens

Why might it be necessary for both pink (lactose-positive) and colorless (lactose-negative) colonies from an initial stool culture on MacConkey agar to be subcultured and tested further for possible pathogens? A. Most Shigella strains are lactose positive B. Most Salmonella strains are maltose negative C. Most Proteus spp. are lactose negative D. Pathogenic E. coli can be lactose positive or lactose negative

D. Pathogenic E. coli can be lactose positive or lactose negative

When performing a Kovac indole test the substrate must contain: a. indole b. tryptophan c. ornithine d. paradimethylaminobenzaldehyde

b. tryptophan

The Voges-Proskaur(VP) test detects which end product of glucose fermentation? a. Acetoin b. Nitrite c. Acetic acid d. Hydrogen Sulfide

a. Acetoin

A positive Simmons Citrate test is seen as a: a. Blue color in the medium after 24 hours of incubation at 35 degrees C b. Red color in the medium after 18 hours of incubation at 35 degrees C c. Yellow color in the medium after 24 hours of incubation at 35 degrees C d. Green color in the medium after 18 hours of incubation at 35 degrees C

a. Blue color in the medium after 24 hours of incubation at 35 degrees C

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 Vi antigen b. test organism with individual antisera for agglutination c. report "no salmonella isolated" d. repeat biochemical identification of the organism

a. Boil suspension of the organism for 10 minutes to inactivate the Vi antigen

Which of the following agars is not selective for Enterobacteriaceae? a. Buffered charcoal yeast extract b. MacConkey (MAC) c. Hektoen enteric d. Xylose-lysine deoxycholate

a. Buffered charcoal yeast extract

What organism in the genus Providencia is incriminated in nosocomial outbreaks in burn units and has been isolated from urine cultures? a. Providencia stuartii b. P. heimbachae c. P. rustigianii d. P. alcalifaciens

a. Providencia stuartii

What organism possesses the Vi antigen? a. Salmonella typhi b. S. sonnei c. Shigella sonnei d. Citrobacter freundii

a. Salmonella typhi

Most strains of Escherichia coli can be presumptively identified on the basis of which characteristic? a. Spot indole-positive b. Citrate-positive c. Methyl red-negative d. Urease-positive

a. Spot indole-positive

An organism that must be incubated in a microaerophilic environment for optimal recovery is: a. campylobacter jejuni b. E.coli c. Pseudomonas aeruginosa d. Proteus mirabilis

a. campylobacter jejuni

A liquid fecal specimen from a 3 month old infant is submitted for culture. The stool culture should detect Salmonella, Shigella and: a. campylobacter species b. clostridium botulinum c. entamoeba hartmanni d. enterotoxigenic E. coli

a. campylobacter species

Campylobacter Jejuni isolation requires the fecal specimen 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 and incubated at both 35 C and at room temperature d. incubated at 35C for 2 hours in Cary-Blair media before inoculating onto selective plating media

a. inoculated onto selective plating media and incubated in reduced oxygen with added CO2 at 42C

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

a. it is oxidase positive

On MacConkey agar, Serratia spp. would appear: a. red. b. colorless. c. green. d. yellow.

a. red

When performing a stool culture, a colony type typical of enteric pathogen is subcultured on blood agar plate. the resulting pure culture is screened with several tests to obtain the results of: TSI: Acid butt, alkaline slant, no gas, no H2S Phenylalanine: Neg motility: pos serological typing: Shigella flexneri(Shigella subgroup B) Serological typing is verified with new kit/controls. The best course of action is: a. report the organism as Shigella f/exneri 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

a. report the organism as Shigella f/exneri without further testing

A green colony with a black center was isolated and presumptively identified as a Salmonella spp. The organism was serotyped with polyvalent antisera; however, the antisera tested negative for all antigens. What is the next course of action? a. Regrow the organism on sheep blood agar, and serotype again the next day. b. Make a suspension, and heat to 100º C for 10 minutes. c. Make a suspension, and place on ice for 30 minutes. d. Report the organism out as a nontypable Salmonella spp.

b. Make a suspension, and heat to 100º C for 10 minutes.

Which genera is positive for phenylalanine deaminase? a. Enterobacter, Eschericia, and Salmonella b. Morganella, Providencia, and Proteus c. Klebsiella and Enterobacter d. Proteus, Escheicia and Shigella

b. Morganella, Providencia, and Proteus

Which of the following is true of all Klebsiella spp. a. All are methyl red positive and Voges-Proskauer negative. b. None produce H2S c. None grow in potassium cyanide broth. d. All are nonmotile.

b. None produce H2S

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 from MacConkey agar had the following biochemical reactions: Test Isolate 1 Isolate 2 TSI: Alk/acid Alk/acid Urea: Positive Negative TDA: Positive Negative H2S: Positive Negative The organisms are most likely: a. Proteus vulgaris and Enterobacter cloacae b. Proteus mirabilis and Serratia marcescens c. Morganella morganii and Klebsiella pneumoniae d. Providencia stuartii and Serratia liquefaciens

b. Proteus mirabilis and Serratia marcescens

>100,000 CFU/ml of a gram negative bacilli were isolated on MacConkey from a urine specimen. Biochemical results were as follows: glucose acid production with gas 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

b. Proteus mirabilis.

A DNase-positive member of the family Enterobacteriaceae is suggestive of a. Enterobacter. b. Serratia. c. Proteus. d. Escherichia.

b. Serratia.

What disease produced by a Salmonella spp. is a severe form of enteric fever? a. Pontiac fever b. Typhoid fever c. Undulant fever d. Malignant fever

b. Typhoid fever

Shigella species characteristically are: a. urease positive b. nonmotile c. oxidase positive d. lactose fermenters

b. nonmotile

Which biochemical characteristic is the most indicative of Hafnia? a. Nitrate reduction positive b. Oxidase negative c. Delayed positive citrate d. Malonate positive

c. Delayed positive citrate

What substance produced by the Salmonella spp., which cause gastroenteritis, has been implicated as a significant virulence factor? a. Hyaluronidase b. Protease c. Enterotoxin d. Endotoxin

c. Enterotoxin

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

c. Escherichia coli / Pseudomonas aeruginosa

Which of the following describes Edwardsiella? a. Positive for urea, lysine decarboxylase, and indole b. Positive for H2S and negative for urea c. Negative for urea and positive for lysine decarboxylase d. Negative for urea and lysine decarboxylase, positive for indole

c. Negative for urea and positive for lysine decarboxylase

What bacterium produces swarming colonies on nonselective media, such as sheep blood agar (SBA)? a. Enterobacter aerogenes b. Klebsiella pneumoniae c. P. mirabilis d. Morganella morganii

c. P. mirabilis

A gram-negative bacillus that is hydrogen sulfide (H2S)-positive, citrate-positive, spot indole-negative, and associated with gastroenteritis in the United States is most likely: a. Klebsiella pneumoniae. b. Proteus vulgaris. c. Salmonella enteritidis. d. Shigella sonnei.

c. Salmonella enteritidis.

Bacillary dysentery caused by this organism is marked by penetration of intestinal epithelial cells following attachment of the organisms to mucosal surfaces, local inflammation, shedding of the intestinal lining, and formation of ulcers that follow the epithelial penetration. What is this organism? a. Enterobacter b. Citrobacter c. Shigella d. Salmonella

c. Shigella

Escherichia coli would appear what color on HE agar? a. Green b. Green with a black center c. Yellow or orange d. Yellow with a black center

c. Yellow or orange

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: negative Urease: positive Ornithine decarboxylase: positive Sucrose: positive H2S: negative Motility at 25 degrees Celsius: positive The most probable identification of this organism is: a. Escherichia coli b. Providencia stuartii c. Yersinia enterocolitica d. Edwardsiella tarda

c. Yersinia enterocolitica

The Escherichia coli serotype O157:H7 is associated with all the following, except a. hemorrhagic diarrhea. b. colitis. c. liver damage. d. hemolytic-uremic syndrome (HUS).

c. liver damage.

An organism that appears red with a black center on XLD agar is lactose-_____ and H2S-_____. a. positive; positive b. positive; negative c. negative; positive d. negative; negative

c. negative; positive

The blue color seen in the Simmon's citrate agar, indicating a positive reaction, results from: a. reduction of citric acid to sodium citrate b. assimilation of carbon from sodium citrate c. production of ammonia from ammonium phosphate d. formation of amines from peptones in the medium

c. production of ammonia from ammonium phosphate

Although some strains may possess K antigen which member of Enterobacteriaceae is classified serologically by O antigen because it lacks the H antigen? a. E.coli b. salmonella typhi c. shigella spp d. proteus mirabilis

c. shigella spp

At which pH does the methyl red (MR) test become positive? A. 7.0 B. 6.5 C. 6.0 D. 4.5

D. 4.5

A suspected case of plague requires which of the following procedures in order to confirm Yersinia pestis? A. Collection of multiple sets of blood cultures B. Incubation of blood cultures at both 28°C and 35°C C. Culture aspirates from bubos to MacConkey agar at room temperature D. All of these options

D. All of these options

Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of: A. Ammonia B. Urea C. CO2 D. Amines

D. Amines

Fever, abdominal cramping, watery stools, and fluid and electrolyte loss preceded by bloody stools 2-3 days before is characteristic of shigellosis but may also result from infections with: a. Campylobacter spp b. Salmonella c. Proteus d. Yersinia

a. Campylobacter spp

A microbiologist is reading stool culture plates. She is looking for enteric pathogens on the MAC plate. What do they look like? a. Clear, colorless colonies b. Large, bright pink colonies c. Small, mucoid, green colonies d. Small, orange colonies

a. Clear, colorless colonies

Enterotoxigenic and enteroinvasive are terms often linked to which of the following bacterial species? a. Escherichia coli b. Salmonella enteritidis c. Shigella sonnei d. Yersinia pestis

a. Escherichia coli

In the carrier state, where are pathogenic salmonella carried? a. Gallbladder b. Liver c. Intestines d. Stomach

a. Gallbladder

What enteric organism may produce a blue-violet pigment on non-blood-containing media? a. Kluyvera b. Shigella c. Ewingella d. Cedecea

a. Kluyvera

An isolate from a stool culture gives the following growth characteristics and biochem rxn: MacConkey: colorless colonies, Hektoen agar: yellow-orange colonies TSI: Acid slant, acid butt no gas/H2S Urea: + These screening rxns are consistent with: a. yersinia enterocolitica b. shigella sonnei c. vibrio parahaemolyticus d. campylobacter jejuni

a. yersinia enterocolitica

A positive reaction for DNA hydrolysis testing is: a. a dark green zone around the colony b. green color fades and the colony is surrounded by a colorless zone c. a zone of red around the colony due to pH change d. no color change in the medium or colony

b. green color fades and the colony is surrounded by a colorless zone

All of the following are characteristics of Shigella spp., except a. nonmotile. b. urea positive. c. hydrogen sulfide negative. d. lysine decarboxylase negative.

b. urea positive.

A blood culture from a 64-year-old male with lymphoma was positive blood culture at 18 hours incubation. The organisms are non-lactose fermenting gram-negative bacilli on MacConkey agar. Further testing gives the following reactions: Oxidase - neg TSI - K/A (no gas) Motility - pos Indole - pos Citrate - pos Ornithine decarboxylase - neg Urea - pos Phenylalanine deaminase - pos VP - neg The genus is: (a) Morganella (b) Proteus (c) Providencia (d) Serratia

(c) Providencia

Which statement is true of Kluyvera? A) All species resemble e. coli growing on MAC agar B) All species produce a violet pigment C) All species ferment glucose at 5 degrees D) All species show a large zone of inhibition around a carbenicillin disk

A) All species resemble e. coli growing on MAC agar

The drugs of choice for treatment of infections with Enterobacteriaceae are: A. Aminoglycosides, trimethoprim-sulfamethoxazole, third-generation cephalosporins B. Ampicillin and nalidixic acid C. Streptomycin and isoniazid D. Chloramphenicol, ampicillin, and colistin

A. Aminoglycosides, trimethoprim-sulfamethoxazole, third-generation cephalosporins

All fecal specimens should be routinely screened for A) Salmonella, shigella, and campylobacter B) Yersinia, Aeromonas, and Virbrio C) Enterohemorrhagic E. coli (EHEC), EPEC, and yersinia D) Pleisomonas and aeromonas

A) Salmonella, shigella, and campylobacter

Which genus is not a member of the resident microbiota of the human GI tract A) Yersinia B) Escherichia C) Proteus D) Citrobacter

A) Yersinia

A routine, complete stool culture procedure should include media for the isolation of E. coli O157:H7 as well as: A. Salmonella, Shigella, Yersinia, Campylobacter, and Staphylococcus aureus B. Vibrio cholerae, Brucella, and Yersinia spp. C. S. aureus, group B streptococci, and group D streptococci D. Clostridium difficile, Clostridium perfringens, and Yersinia spp.

A. Salmonella, Shigella, Yersinia, Campylobacter, and Staphylococcus aureus

A stool culture from a 30-year-old man suffering from bloody mucoid diarrhea gave the following results on differential enteric media: MacConkey agar = clear colonies XLD agar = clear colonies Hektoen agar = green colonies Salmonella-Shigella agar = small, clear colonies Which tests are most appropriate for identification of this enteric pathogen? A. TSI, motility, indole, urease, Shigella typing with polyvalent sera B. TSI, motility, indole, lysine, Salmonella typing with polyvalent sera C. TSI, indole, MR, VP, citrate D. TSI, indole, MR, and urease

A. TSI, motility, indole, urease, Shigella typing with polyvalent sera

Enterobacter sakazakii can best be differentiated from Enterobacter cloacae by which of the following characteristics? A. Yellow pigmentation and negative sorbitol fermentation B. Pink pigmentation and positive arginine dihydrolase C. Yellow pigmentation and positive urease D. H2S production on TSI

A. Yellow pigmentation and negative sorbitol fermentation

Following a 2-week camping trip to the Southwest (US), a 65-year-old male patient was hospitalized with a high fever and an inflammatory swelling of the axilla and groin lymph nodes. Several blood cultures were obtained, resulting in growth of gram-negative rods resembling "closed safety pins." The organism grew on MacConkey's agar showing non-lactose-fermenting colonies. Testing demonstrated a nonmotile rod that was biochemically inert. What is the most likely identification? A. Yersinia pestis B. Klebsiella pneumoniae C. Proteus vulgaris D. Morganella morganii

A. Yersinia pestis

Which of the following reagents is added to detect the production of indole? A. p-Dimethylaminobenzaldehyde B. Bromcresol purple C. Methyl red D. Cytochrome oxidase

A. p-Dimethylaminobenzaldehyde

What organism is most likely given the following results? -Motile, Lysine decarboxylase negative, Ornithine decarboxylase positive, Arginine dihydrolase positive A) Enterobacter aerogenes B) Enterobacter cloacae C)Klebsiella pneumoniae subsp. pneumoniae D) Shigella

B) Enterobacter cloacae

The oxidase test should be performed? A) on colonies grown on chocolate agar only B) On young colonies of nonlactose fermenters growing on SBA C) On colonies grown on MAC agar or EMB D) Only on lactose fermenters and gram positive rods

B) On young colonies of nonlactose fermenters growing on SBA

The majority of clinical laboratories with a microbiology department should have the capability of serotyping which pathogenic Enterobacteriaceae? A. Yersinia enterocolitica, Shigella spp. B. E. coli O157:H7, Salmonella spp., Shigella spp. C. Yersinia pestis, Salmonella spp. D. Edwardsiella spp., Salmonella spp.

B. E. coli O157:H7, Salmonella spp., Shigella spp.

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

B. Hektoen, MacConkey, Campy, colistin-nalidixic acid (CNA) agars

Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the: A. Ratio of lactose to glucose B. Ability to detect H2S production C. Use of sucrose in the medium D. Color reaction denoting production of acid

C. Use of sucrose in the medium

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

b. escherichia coli

In addition to being a group of gram-negative bacteria considered normal flora of the gastrointestinal tract of humans and animals, which one of the following also contains agents of important diseases such as gastroenteritis and enteric fevers, urinary tract infections, and bacterial pneumonia? a. Neisseriaceae b. Micrococcaceae c. Enterococcus d. Enterobacteriaceae

d. Enterobacteriaceae

For the most part, all Enterobacteriaceae are positive for which biochemical reactions? a. Glucose, oxidase, and catalase b. Glucose, indole, and oxidase c. Glucose, reduce nitrates to nitrites, and oxidase d. Glucose, catalase, and reduce nitrates to nitrites

d. Glucose, catalase, and reduce nitrates to nitrites

Escherichia coli can produce a toxin similar to Shigella dysenteriae and can cause hemorrhagic colitis. What other organ does it affect? a. Heart b. Lungs c. Liver d. Kidney

d. Kidney

Which one of these genera is among the least biochemically reactive members of the Enterobacteriaceae? a. Proteus b. Pseudomonas c. Citrobacter d. Shigella

d. Shigella

Why is it that most cases of salmonella food poisoning are not treated with antibiotics? a. The organisms are very resistant to antibiotics. b. Antibiotics cannot reach the organisms, because they are deeply embedded in the intestinal walls. c. Antibiotics would only kill the bacteria, then release the endotoxins into the blood, making things worse. d. The disease is self-limiting and will subside on its own.

d. The disease is self-limiting and will subside on its own.

Cold enrichment of feces (incubation at 4 degrees C) in phosphate buffered saline prior to subculture onto enteric media enhances the recovery of? a. Enterotoxigenic E. coli b. Salmonella paratyphi c. Hafnia alveri d. Yersinia enterocolitica

d. Yersinia enterocolitica

What bacterium is the causative agent of the plague? a. Salmonella enteritidis b. Citrobacter freundii c. Shigella sonnei d. Yersinia pestis

d. Yersinia pestis

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

d. boil the organism and retest with the antisera

Escherichia coli strains have all the following properties, except a. indole production. b. fermentation of glucose and lactose. c. methyl red (MR) positive, Voges-Proskauer (VP) negative. d. can use citrate as a sole carbon source.

d. can use citrate as a sole carbon source.

Vibrio parahaemolyticus is best isolated 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

d. thiosulfate citrate bile salts (TCBS) agar

Which of the following is the most appropriate organism and media combination? a. vibrio species---skirrow b. enterohemorrhagic E. coli---phenylethyl extract (PEA) c. campylobacter species---charcoal yeast extract d. yersinia enterocolitica---CIN

d. yersinia enterocolitica---CIN