VIBRIO AEROMONAS, CAMPYLOBACTER, HELICOBACTER

Select the media of choice for recovery of Vibrio cholerae from a stool specimen

Thiosulfate-citrate-bile-sucrose (TCBS) agar and alkaline peptone water (APW) broth

A visitor to South America who returned with diarrhea is suspected of being infected with V. cholerae. Select the best medium for recovery and identification of this organism

TCBS agar

Which of the following is not true regarding virulent strains of Vibrio cholerae?

Nonmotile

The enterotoxins of both Vibrio cholerae O1 and noninvasive (toxigenic) strains of Escherichia coli produce serious diarrhea by what mechanism?

Stimulation of adenylate cyclase, which gives rise to excessive fluid secretion by the cells of the small intestine

Which group of tests best differentiates Helicobacter pylori from C. jejuni?

Urease, nitrate, and hippurate hydrolysis

Which are the best two tests to differentiate A. hydrophilia from Pleisomonas shigelloides?

DNase and VP

SITUATION: Several attendees of a medical conference in the Gulf coast area became ill after frequenting a seafood restaurant. A presumptive identification of Vibrio cholera was made after stool specimens from several subjects grew clear colonies on MacConkey agar and yellow colonies on TCBS agar. Which key tests would help eliminate Aeromonas and Plesiomonas spp.?

Mannitol fermentation, Na+ requirement

The species of Campylobacter noted to produce septicemia, septic arthritis, meningitis, jaundice with hepatomegaly, and thrombophlebitis in debilitated patients is

C. fetus

Infection of the gastric mucosa leading to gastritis or peptic ulcers is most commonly associated with

Helicobacter pylori

Identify the fermentative agent that may infect reptiles and fish as well as humans when they are exposed to contaminated soil or water

Aeromonas

SITUATION: Abdominal pain, fever, vomiting, and nausea prompted an elderly male to seek medical attention. A watery stool specimen producing no fecal leukocytes or erythrocytes was cultured and grew a predominance of gram-negative fermentative bacilli. The colonies were beta-hemolytic on blood agar and cream colored on MacConkey agar. The colonies were both oxidase and catalase positive. What is the

Aeromonas hydrophilia

Explosive watery diarrhea with severe abdominal pain after eating raw shellfish is most characteristic of infection caused by

Vibrio parahemolyticus

Which atmospheric condition is needed to recover Campylobacter spp. from specimens inoculated onto a Campy-selective agar at 35°C-37°C and 42°C?

5% O2, 10% CO2, and 85% N2

Helicobacter is urea negative

FALSE

A curved gram-negative rod producing oxidase-positive colonies on blood agar was recovered from a stool culture. Given the following results, what is the most likely identification?

Lysine decarboxylase = + Arginine decarboxylase = Neg

Indole = + KIA = Alk/Acid

VP = Neg Lactose = Neg

Urease = ± String test = Neg

TCBS agar = Green colonies

Vibrio parahaemolyticus

Vibrio vulnificus is a well-established human pathogen that is known to cause

Wound infections

he classic toxigenic strains of which serogroup are implicated in epidemic infections of Vibrio choleare?

O1

Vibrio is oxidase positive

TRUE

A fermentative gram-negative bacillus that is oxidase positive, motile, and grows well on MacConkey agar is

Aeromonas hydrophila

Which of the following has a negative oxidase test?

HAFNIA

Which of the following is true concerning Campylobacter jejuni?

A leading cause of bacterial diarrhea worldwide

A gram-negative S-shaped rod recovered from selective media for Campylobacter species gave the following results:

Catalase = + Oxidase = + Motility = +

Hippurate hydrolysis = +

Growth at 42°C = + Nalidixic acid = Susceptible

Pigment = Neg

Grape odor = Neg Cephalothin = Resistant

The most likely identification is:

Campylobacter jejuni

For the selective isolation of Vibrio spp. the recommended agar is

Thiosulfate-citrate-bile salt-sucrose-agar

Which of the following is not a correct description regarding Aeromonas hydrophila?

ONPG negative

Which is the best rapid test to differentiate Plesiomonas shigelloides from a Shigella species on selective enteric agar?

Oxidase

An example of a halophilic microorganism is

Vibrio parahaemolyticus

The species of Vibrio closely associated with rapidly progressing wound infections seen in patients with underlying liver disease is

V. vulnificus

Campylobacter jejuni is

Hippurate hydrolysis positive

The symptom of diffuse, watery diarrhea that produces a relatively clear stool containing mucus flecks is suggestive of an infection caused by

Vibrio cholerae

Campylobacter is oxidase positive

TRUE

Which of the following tests should be done first in order to differentiate Aeromonas spp. from the Enterobacteriaceae?

OXIDASE

Fecal cultures are inoculated on thiosulfate-citrate-bile salts-sucrose agar specifically for the isolation of

VIBRIO