Impact of imipenem/cilastatin therapy on normal fecal flora.

The impact of parenteral imipenem/cilastatin therapy on the bowel flora of six patients was evaluated. Stool samples were collected before and during therapy and qualitative and quantitative bacteriologic studies were performed. Imipenem had no effect on total microorganism counts. Two patients acquired Candida albicans during therapy, and three patients acquired Proteus species. Pseudomonas species in one patient acquired resistance. Imipenem appears to have a relatively modest effect on the bowel flora and apparently does not readily induce resistance in the resident flora as compared with other agents.