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January 1971

Persistence of Ampicillin-Sensitive Salmonella thompsoni Due to Fecal Penicillinase

Author Affiliations

New York

From the Department of Medicine, Cornell University Medical College, New York. Drs. Mandell and Hook are now with the University of Virginia School of Medicine, Charlottesville.

Arch Intern Med. 1971;127(1):137-138. doi:10.1001/archinte.1971.00310130141025

A 43-year-old woman continued to carry Salmonella thompsoni in her stool despite large oral doses of ampicillin sodium. The organisms were sensitive to ampicillin but the stool was found to contain large quantities of penicillinase which inactivated the antibiotic. Treatment with ampicillin plus cephaloglycin dihydrate resulted in negative stool cultures, probably because cephaloglycin bound penicillinase. Thus, destruction of ampicillin by penicillinase elaborated by enteric organisms was the probable mechanism for persistence of salmonellae in this patient's stools.

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