NEET PG / USMLE – MCQ 10

A patient being treated with clindamycin for aspiration pneumonia develops diarrhea. The stool contains a toxin that kills cultured epithelial cells. Stool culture grows an anaerobic gram-positive rod. The same organism is cultured from his bedpan. Which of the following is most likely to sterilize the bedpan?
(A) Boiling for 45 minutes
(B) Exposure to benzalkonium chloride for 1 hour
(C) Exposure to ethyl alcohol for 1 hour
(D) Exposure to saturated steam (121°C) for 15 minutes
(E) Heating in an oven at 150°C for 30 minutes

Correct answer : (D) Exposure to saturated steam (121°C) for 15 minutes

Proper autoclave treatment (Exposure to saturated steam (121°C) for 15 minutes) will inactivate all fungi, bacteria, viruses and also bacterial spores, which can be quite resistant. Although benzalkonium chloride is effective against the vegetative state, it is ineffective against the spores.

Explanation contributed by Raja Muthusami. If you like to publish a question here, just email the question with correct answer and suitable explanation to pgblazerofficial (at) gmail (dot) com.