Deck 34: Gastrointestinal Infections and Food Poisoning

Question 1

Disease caused by which of the following organisms has fever, abdominal cramping, diarrhea, and stools with gross blood and pus?

A) Staphylococcus aureus
B) Clostridium difficile
C) Campylobacter jejuni
D) Bacillus cereus

Answer 1

C

Question 2

What is the most significant predisposing factor to Clostridium difficile-associated disease?

A) Antimicrobial therapy
B) Young age
C) Consumption of undercooked beef
D) Travel to developing countries

Answer 2

A

Question 3

What is the environmental reservoir of Campylobacter?

A) Lakes and rivers
B) Fish
C) Arthropod vector
D) Wild and domestic animals

Answer 3

D

Question 4

What virus causes an acute self-limiting diarrheal illness that is highly contagious through contaminated food, water, fomites, or person-to-person contact and is associated with vomiting and low-grade fever?

A) Astroviruses
B) Rotaviruses
C) Enteric arenaviruses
D) Norovirus

Question 5

What is the most common cause of bacterial gastroenteritis in the world?

A) Salmonella Typhi
B) Campylobacter jejuni
C) Shigella sonnei
D) Yersinia enterocolitica

Question 6

All of the following organisms can cause enterotoxin-mediated diarrhea, except

A) Salmonella Typhi.
B) Clostridium perfringens.
C) Vibrio cholerae.
D) Staphylococcus aureus.

Question 7

A fecal isolate identified as E. coli produces clear colonies on MacConkey agar with sorbitol. You should suspect

A) Shigella sp.
B) Enterotoxigenic E. coli.
C) Enterohemorrhagic E. coli.
D) The identification is incorrect.

Question 8

The presence of yellow colonies on thiosulfate-citrate-bile salt-sucrose medium is suggestive of

A) Aeromonas hydrophila.
B) Vibrio cholerae.
C) Yersinia enterocolitica.
D) Shigella sp.

Question 9

What common organism invades the full thickness of the bowel with lymphatic spread?

A) Vibrio cholerae
B) Campylobacter jejuni
C) Salmonella Typhi
D) Aeromonas spp.

Question 10

Presence of red colonies with black centers on xylose-lysine-decarboxylase medium is indicative of

A) lactose fermentation and utilization of citrate.
B) lactose fermentation and H₂S positive.
C) nonlactose fermentation and tryptophan positive.
D) nonlactose fermenter and H₂S positive.

Question 11

All of these patient history questions will help focus the search for the cause of diarrhea, except:

A) Does the patient have a history of previous gastrointestinal symptoms?
B) Did the patient eat any hot food?
C) Does the patient have an underlying illness?
D) Is the patient taking any medication?

Question 12

What type of diarrheal illness produces fever, leukocytosis in peripheral blood, and fecal leukocytes?

A) Diarrhea in which the mucosal surface is invaded
B) Diarrhea in which the full bowel thickness is invaded
C) Diarrhea caused by endotoxins
D) Diarrhea caused by enterotoxins

Question 13

What type of diarrheal illness has a rapid onset of symptoms after food ingestion (usually <12 hours)?

A) Diarrhea where the mucosal surface is invaded
B) Diarrhea where the full bowel thickness is invaded
C) Diarrhea caused by endotoxins
D) Diarrhea caused by enterotoxins

Question 14

What is the most common cause of travelers' diarrhea?

A) Giardia lamblia
B) Escherichia coli
C) Entamoeba histolytica
D) Clostridium difficile

Question 15

What virus is the leading cause of diarrhea in children younger than age 5 years?

A) Enteric adenoviruses
B) Astroviruses
C) Rotavirus
D) Calicivirus

Question 16

All the following organisms invade the bowel mucosal surface to produce diarrhea, except

A) Salmonella spp.
B) Vibrio cholerae.
C) Campylobacter spp.
D) Shigella spp.

Question 17

What is the most common cause of death among patients with diarrhea?

A) Sepsis
B) Septic shock
C) Dehydration
D) Secondary bacterial infections

Question 18

What defense mechanism does the colon have to guard against infection?

A) IgA secretion
B) IgE secretion
C) Ciliated epithelial cells
D) Acid secretion

Question 19

What type of diarrheal illness has no fever and no blood or pus in the stool?

A) Diarrhea where the mucosal surface is invaded
B) Diarrhea where the full bowel thickness is invaded
C) Diarrhea caused by endotoxins
D) Diarrhea caused by enterotoxins

Question 20

The urea breath test is a noninvasive test to detect infection caused by

A) Listeria monocytogenes.
B) Vibrio cholerae.
C) Helicobacter pylori.
D) Campylobacter jejuni.

Question 21

A physician has requested a stool culture for Yersinia, which of the following would be the most appropriate medium to use?

A) Thiosulfate-citrate-bile salt-sucrose
B) Hektoen-enteric
C) Colistin-irgasan-novobiocin
D) Xylose-lysine-deoxycholate

Question 22

What diarrheal pathogen can produce a disease that can lead to hemolytic-uremic syndrome?

A) Enterohemorrhagic Escherichia coli (EHEC)
B) Enteroinvasive E. coli (EIEC)
C) Enteropathogenic E. coli (EPEC)
D) Enterotoxigenic E. coli (ETEC)

Question 23

Although uncommon, what intestinal parasite is known to leave the colon and cause metastatic diseases, especially liver abscesses?

A) Giardia lamblia
B) Entamoeba histolytica
C) Cryptosporidium parvum
D) Microsporidia

Question 24

What toxin does Shigella spp. produce?

A) Typhi
B) Enterotoxin
C) Shiga
D) Campy

Question 25

What organism grows best at 42° C and in a reduced oxygen atmosphere (5% to 10%)?

A) Shigella sonnei
B) Clostridium difficile
C) Campylobacter jejuni
D) Escherichia coli

Question 26

What is the most commonly identified intestinal parasite in the United States?

A) Giardia lamblia
B) Entamoeba histolytica
C) Cryptosporidium parvum
D) Microsporidia

Question 27

This is a form of food poisoning that can be life threatening even for otherwise healthy patients.

A) S. aureus
B) B. cereus
C) C. difficile
D) C. botulinum

Question 28

What is the most important cause of iatrogenic diarrhea in adults?

A) Yersinia enterocolitica
B) Cryptosporidium jejunum
C) Vibrio parahaemolyticus
D) Clostridium difficile

Question 29

What organism that causes gastroenteritis can be found in aquaculture-farmed fish?

A) Salmonella
B) Campylobacter
C) Vibrio
D) Shigella

Question 30

What organ is colonized in a patient that carries Salmonella typhi?

A) Colon
B) Gallbladder
C) Rectum
D) Small intestine

Question 31

A man and his family drive to the coast and have an oyster dinner. A couple of days later, the man arrives at the emergency department with a fever, bullous skin lesions, and diarrhea. He is extremely ill and appears septic. The microbiologist notices curved gram-negative rods on the stool Gram stain. What is the most probable organism causing this condition?

A) Yersinia enterocolitica
B) Cryptosporidium jejuni
C) Vibrio vulnificus
D) Vibrio cholerae

Question 32

What types of stools are characteristic of someone who has cholera?

A) Black-blood stools
B) Coffee-ground stools
C) Black tar stools
D) Rice-water stools

Question 33

All of the following organisms are commonly implicated in a foodborne outbreak, except

A) Staphylococcus aureus.
B) Salmonella Typhi.
C) Clostridium botulinum.
D) Clostridium perfringens.

Question 34

A microbiologist is reading a Gram stain and observes gram-negative, curved rods with a seagull-wing appearance. What is the most likely organism?

A) Campylobacter or Vibrio
B) Shigella or Vibrio
C) Campylobacter or Shigella
D) All of the above