Deck 34: Gastrointestinal Infections and Food Poisoning

Question 1

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

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

Answer 1

C
Rotaviruses are the major cause of diarrhea in children younger than age 5,causing an estimated 130 million episodes of illness worldwide each year.

Question 2

What virus causes an acute self-limited diarrheal illness that is highly contagious in closed quarters but is associated with vomiting and low-grade fever?

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

Answer 2

D
The noroviruses are named after the original strain (Norwalk virus),first isolated in patients from a town with that name in Ohio in 1968.These viruses cause an acute,self-limited diarrheal illness associated with vomiting and low-grade fever.The disease is highly contagious and is transmitted by the fecal-oral route,fecally contaminated food or water,environmental fomites,and by person-to-person contact.

Question 3

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

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

Answer 3

B
Although various Campylobacter spp.have been isolated as a cause of diarrhea,C.jejuni is the most common bacterial cause of gastroenteritis in the world.

Question 4

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 5

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

Question 6

What type of diarrheal illness has a rapid onset of symptoms after food ingestion (usually less than 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 7

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

A) IgA antibody is produced.
B) IgE antibody is produced.
C) Nonspecific immune defenses are resident here and take care of pathogens.
D) The anatomic structure makes it tough for organisms to adhere.

Question 8

What diarrheal illness occurs when organisms invade through the bowel wall,cause bacteremia,and also cause a mesenteric lymphadenitis that may be confused with appendicitis?

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 9

What is the environmental reservoir of Campylobacter?

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

Question 10

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 11

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 12

How is diarrhea usually contracted?

A) By air
B) By blood
C) By contaminated food or water
D) By respiratory droplet

Question 13

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

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

Question 14

How does the small intestine try to prevent infection?

A) Caustic secretions
B) Acidic secretions
C) Anatomic structure
D) Peristalsis

Question 15

Which of the following is an opportunistic virus that can lead to diarrhea in an immunocompromised host?

A) Rubella
B) Parvo B19
C) Cytomegalovirus
D) Filovirus

Question 16

All of the following additional patient history questions will help narrow the search for the pathogen 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 17

What is the most common cause of travelers' diarrhea?

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

Question 18

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 19

All of the following organisms can cause enterotoxin-mediated diarrhea EXCEPT:

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

Question 20

Why is the travel history of the patient important when evaluating a person with diarrhea?

A) Travel to different countries puts one at risk for various infections.
B) Some countries are dirtier than others.
C) The Unites States is clean, and usually bad infections cannot be contracted here.
D) All of the above.

Question 21

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

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

Question 22

What types of stools are characteristic of cholera?

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

Question 23

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

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

Question 24

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 25

What condition caused by diarrhea will trigger kidney failure,liver failure,myocardial infarction,and death?

A) Metabolic alkalosis
B) Metabolic acidosis
C) Volume depletion
D) Electrolyte imbalance

Question 26

What toxin do Shigella spp.produce?

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

Question 27

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 the doctor questions whether he is septic.Blood and stool specimens are collected.The microbiology technician 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 28

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

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

Question 29

What intestinal parasite is able to leave the intestines and cause metastatic diseases,especially liver abscesses?

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

Question 30

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

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

Question 31

A microbiologist is reading a Gram stain and observes gram-negative,curved rods with a seagull-wing appearance.What organism could this be?

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

Question 32

What diarrheal pathogen can produce a disease that may lead to hemolytic-uremic syndrome (hemolytic anemia,low platelet count,and kidney failure)?

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

Question 33

All of the following organisms have been implicated in a food-borne outbreak EXCEPT:

A) Staphylococcus aureus
B) Salmonella spp.
C) Clostridium botulinum
D) Vibrio cholerae