Non-Enteric GI Pathogens Flashcards
A gram-negative bacillus isolated from a stool specimen produces clear colonies on MacConkey agar and yellow colonies on thiosulfate citrate bile salt sucrose medium. The isolate is subcultured to a sheep blood agar plate with an O/129 disk. The isolate is sensitive to O/129 and is oxidase-positive. You should suspect:
a. Vibrio parahaemolyticus
b. Vibrio cholerae
c. Plesiomonas
d. Aeromonas
b. Vibrio cholerae
(green colonies on MAC: V. parahaemolyticus)
Which of the following Vibrio spp. would you expect to be most likely isolated from a blood culture?
a. V. cholerae
b. V. parahaemolyticus
c. V. vulnificus
d. V. alginolyticus
V. vulnificus
Which of the following genera is typically microaerophilic?
a. Helicobacter
b. Aeromonas
c. Plesiomonas
d. Vibrio
Helicobacter
Campylobacter jejuni is most noted for causing:
a. Wounds
b. Septicemia
c. Gastric ulcers
d. Gastroenteritis
Gastroenteritis
Which of the following is a risk factor for acquiring V. alginolyticus infection?
a. Farming
b. Hunting
c. Fishing or swimming in ocean water
d. Drinking unpasteurized milk
Fishing or swimming in ocean water
An oxidase-positive, indole-positive, β-hemolytic, gram-negative bacillus resistant to O/129, cannot grow in 6% NaCl broth, and is a non–lactose fermenter on MacConkey agar is isolated from an adult stool culture. You should suspect:
a. Aeromonas hydrophila
b. Aeromonas caviae
c. Plesiomonas shigelloides
d. Vibrio parahaemolyticus
Aeromonas hydrophila
Darting motility is a characteristic of:
a. Aeromonas
b. Campylobacter
c. V. cholerae O1
d. V. cholerae non-O1
Campylobacter
Which of the following tests is most helpful in differentiating C. jejuni from the other Campylobacter spp.?
a. Nitrate reduction
b. Urease activity
c. Hippurate hydrolysis
d. Susceptibility to nalidixic acid
Hippurate hydrolysis
What nonculture methods are used to diagnosis Helicobacter
pylori infections?
-urea breath test
The most commonly used nonculture method for the diagnosis of H. pylori is the noninvasive 1C- or 1C-labeled urea breath test. The patient receives an oral dose of labeled urea.
Urease activity by H. pylori results in the formation of radioactive-labeled COz, which is absorbed into the bloodstream and then exhaled. Other nonculture methods include microscopic examination of stained gastric tissue and direct collection
When attempting to recover enteric Campylobacter spp., which
1.specimen,
2. media, and
3. incubation conditions should be used?
- and rectal swabs; stool samples are preferred.
- CAMPY-BAP (Brucella agar-based medium, with 10% sheep red blood cells and a combination of antimicrobials.)
- Charcoal cefoperazone deoxycholate agar is an alternative.
Vibrio Species
- Vibrio cholerae
- Vibrio parahaemolyticus
- Vibrio vulnificus
Vibrio spp. motility
shooting star motility
Kanagawa toxin (phenomenon) is associated with?
V. parahaemolyticus
3 serotypes of V. cholerae O1
Inaba
Ogawa
Hikojima
V. cholerae O1 serotypes
antigentic determinant A & C
Inaba
V. cholerae O1 serotypes
antigenic determinant A & B
Ogawa
V. cholerae O1 serotypes
expresses both Inaba and Ogawa antigens
Hikojima
Side note:
Vibrio spp.
Is halophilic (salt-loving): requires 1% NaCl in the growth media (BAP, MAC, and biochemical tests media)
~
enrichment broth for vibrio?
Alkaline peptone water broth
pH 8.6
Campylobacter…if culture will be delayed, transport the spx in ___?
- This medium has demonstrated its effectiveness in recovery of various microorganisms like Vibrio parahaemolyticus and species of Salmonella, Shigella and Yersinia.
Cary-Blair transport medium
-Cary Blair Transport Medium is used for transportation and preservation of clinical specimens, primarily faecal
and rectal samples.