04-20-2008, 05:01 PM
1. A 2-year-old girl has had fever and bloody diarrhea for 10 days. A stool culture obtained 7 days ago grew Salmonella species sensitive to amoxicillin. A blood culture was negative. Despite beginning oral amoxicillin therapy 4 days ago, her diarrhea has persisted. Current examination shows no other abnormalities except for a temperature of 38.6 C (101.5 F). Which of the following is the most likely explanation for the failure of amoxicillin to improve her symptoms?
A
) Amoxicillin does not alter the course of Salmonella enteritidis
B
) Amoxicillin has caused pseudomembranous colitis
C
) Amoxicillin is absorbed at the level of the jejunum, leaving no drug to be delivered to the colon
D
) Oral amoxicillin is not absorbed into the systemic circulation in the presence of diarrhea
E
) Salmonella has expressed an inducible β-lactamase that inactivates amoxicillin