MCQs on Escherichia Coli (E.coli) infections and key characteristics: Medical microbiology

          MCQs on Escherichia Coli (E.coli) infections and key characteristics

1. What is the primary habitat of Escherichia coli?
a) Soil
b) Human intestines
c) Human nose 
d) Human skin

2. Which of the following infection is commonly associated with extraintestinal strains of E. coli?

a) Community acquired pneumonia
b) Community acquired urinary tract infection (UTI)    
c) Hemorrhagic diarrhea
d) Traveler's  diarrhea

3. What type of toxin is produced by Enterotoxigenic E. coli (ETEC) strains?

a) Alpha toxin 

b) Endotoxins
c) Heat-Labile Enterotoxin (LT)

d) Shiga toxin-producing E. coli (STEC) 

4. Which type of E. coli is often referred to as "traveler's diarrhea" due to its association with contaminated water and food in developing countries?
a) Enterotoxigenic E. coli (ETEC)
b) Enteropathogenic E. coli (EPEC)
c) Enterohemorrhagic E. coli (STEC)
d) Enteroaggregative E. coli (EAEC)

5. Which of the following transport media should be used for the collection and transport of the fecal specimen collected for the diagnosis of E.coli?
a) Blood agar
b) Nutrient agar media
c) Tryptic soy broth transport media
d) Stuart transport media  

6. Which strain of E. coli is commonly found in the intestines and does not usually cause illness, but is used as an indicator of fecal contamination in water?
a) EHEC

b) EPEC    
c) ETEC
d) E. coli O157:H7

7. The Shiga toxin produced by some strains of E. coli can lead to which serious condition?
a) Influenza   

b) Hemolytic uremic syndrome (HUS) 

c) Malaria 
d) Tuberculosis

8. Which of the following media is a selective media used for the isolation and identification of E.coli and differentiation of Enterobacteriaceae?
a) MacConkey agar
b) Nutrient agar
c) Sabouraud dextrose agar
d) Xylose-lysine deoxycholate agar (XLD)

9. E. coli O157:H7 is classified as which type of strain?

a) Enteropathogenic E. coli

b) Enterotoxigenic E. coli

c) Enterohemorrhagic E. coli     

d) Enteroaggregative E. coli

10. Which strain of E. coli is notorious for causing severe food poisoning outbreaks linked to undercooked ground beef?
a) ETEC
b) EPEC
c) EHEC      
d) EAEC

11. Which of the following are the key positive biochemical reaction tests for identification of E.coli?

a) Indole   

b) Methyl red    

c) Voges Proskauer 

d) Simmons citrate 

e) Hydrogen Sulfide (TSI) 

f) Urea 

g) Lactose  

h) Mannitol  

12. E. coli is the causative agent for which of the following infection common in premenopausal women?

a) Jaundice

b) Influenza

c) Pneumonia

d) Vaginitis   

13. Name the media used for the selection and differentiation of  E. coli O157:H7 in stool specimens

a) Eosin methylene blue (EMB) agar

b) Mannitol salt agar

c) MacConkey sorbitol agar     

d) New York City (NYC) agar 

Answers:

1. b) Human intestines

2. b) Community acquired urinary tract infection (UTI)    

3. c) Heat-Labile Enterotoxin (LT)

4. a) Enterotoxigenic E. coli (ETEC)

5. d) Stuart transport media

6. b) EPEC

7. b) Hemolytic uremic syndrome (HUS)    

8. a) MacConkey agar

9. c) Enterohemorrhagic E. coli  (EHEC) 

10. c) EHEC   

11. a) Indole, b) Methyl red, g) Lactose, and h) Mannitol

12. d) Vaginitis

13. c) MacConkey sorbitol agar