The microbial flora and antimicrobial therapy of neonatal peritonitis.

Data from 31 infants with gastrointestinal perforation were analyzed to determine the microorganisms usually present in the peritoneum and blood, and the antibiotic susceptibility of those organisms. Multimicrobial contamination of the peritoneal cavity was present in over one-half of the patients and 23% were found to have mixed aerobic-anaerobic peritoneal flora. Most common organisms were E. coli and Bacteroides species. Blood cultures were positive in 32% of patients, most frequently growing E. coli. Among numerous antibiotics tested, only gentamicin was effective against all Enterobacteriaceae isolated. Clindamycin was 99% effective against Bacteroides species isolated and 90% against other anaerobes. Group D streptococcus was the most frequently isolated gram positive aerobe. Based on these findings, empiric therapy with ampicillin, gentamicin and clindamycin is recommended for neonates with gastrointestinal perforation. Adjustments in therapy for individual patients should be based upon culture and sensitivity data.