15. GI infections

Question 1

A 32 year old homosexual man complains of bloody diarrhea for 5 days. Testing is done showing a non-motile, gram -ve rod. What is true of this infectious agent?

A. Has animal reservoir 
B. Characterized by the presence of AAF
C. Moves from host to host cell with aid of actin filaments
D. Rapid fermenter of Lactose
E. Has Emetic Toxin

RFA

Answer 1

Ans. C Move from host to host cell with aid of actin filaments is a property true of Shigella the described infectious agent. The only non-motile Enterobacteriaceae are Shigella and Klebsiella

A. Shigella only goes person to person

B. AAF (aggregative adherence fimbriae)- is a trait that belongs to EAEC

D. Rapid fermenter of Lactose is a trait of E. Coli

E. Emetic toxin is characteristic of Bacillus Cereus- think old white rice

Question 2

A 30 year old man comes to the doctor complaining of bloody diarrhea for the past week. After testing it is noted that the infectious lactose postive agent posses AAF, what is the infectious agent?

A. EIEC
B. Shigella 
C. STEC
D.ETEC
E. EAEC

RFA

Answer 2

ANS.E- EAEC- As with all E. Coli is lactose + and characterized by AAF( aggregative adherence fimbriae)

A. EIEC= Enteroinvasive E. Coli- No shiga toxin, very infectious, invades LI

B. Shigella- notable feature: non-motile, gram - rod , Endotoxin O and Exotoxin , Lactose -

C. STEC- found in cattle and sheep causes hemorrhagic colitis, HUS and thrombotic thrombocytopenic purpura , Has Verotoxin Similar to shiga toxin

D. ETEC- Traveler’s diarrhea is non inflammatory