Antimicrobial management of postoperative infections in abdominal surgery: single or combination regimen?

In a prospective, controlled, randomized study, the clinical and bacteriologic efficacy of imipenem/cilastatin was compared with that of a standard combination of an aminoglycoside, amoxicillin, and clindamycin in patients with serious postoperative infections. Doses used were imipenem/cilastatin 1 gm q 8 hr, amoxicillin 2 gm q 8 hr, and clindamycin 0.6 gm q 6 hr. Aminoglycoside doses were individualized and monitored six times weekly with serum concentration assays. Sixty-three patients were entered into the study: 31 in the imipenem/cilastatin group and 32 in the combination group. Diagnoses included pneumonia (ten in the imipenem/cilastatin group and seven in the combination group), peritonitis (eight in the imipenem/cilastatin group and 15 in the combination group), and septicemia (eight in the imipenem/cilastatin group and three in the combination group). The two groups were comparable with respect to sex, age, underlying diseases, and duration of antibiotic therapy. In the imipenem/cilastatin group, 26 patients were cured and one improved (87%). In the combination group, 21 were cured and five improved (81%). Four patients receiving imipenem/cilastatin and six receiving the combination therapy failed to respond to treatment. Eighty percent of the bacterial isolates were eradicated, and 15% were suppressed in the imipenem/cilastatin group. Corresponding frequencies in the combination group were 84% and 11%, respectively. Isolated pathogens persisted in 5% of the patients in each group. It is concluded that imipenem/cilastatin appears to be an effective and well-tolerated alternative to a triple antibiotic combination in the treatment of serious postoperative infections.(ABSTRACT TRUNCATED AT 250 WORDS)