The microbiology of neonatal peritonitis

D. L. Mollitt, J. J. Tepas 3rd and J. L. Talbert
Department of Surgery, University of Florida, Jacksonville 32209.

To review the bacteriology of neonatal intra-abdominal sepsis, we reviewed peritoneal cultures from 86 newborns undergoing operation for necrotizing enterocolitis (NEC) for the type and incidence of microorganism recovered. As a control, we conducted a similar review in 59 children with perforated appendicitis during the same period. Necrotizing enterocolitis was characterized by a lower incidence of polymicrobial contamination (1.7 organisms per patient vs 2.4 organisms per patient, NEC vs appendicitis) and an uncharacteristic pattern of isolates. Although enteric gram-negative bacilli were recovered in 80% of newborns, the incidence of Escherichia coli was only 21% in the NEC group vs 69% in the appendicitis group, while Klebsiella and Enterobacter species represented the most common gram-negative isolates recovered (63% vs 17%). More than 50% of neonatal cultures yielded gram-positive cocci, most frequently coagulase-negative staphylococci (30% vs 0%) and enterococci (17% vs 5%), as compared with more frequent streptococcal isolates in the appendicitis group (50% vs 10%). Anaerobes were seldom recovered in NEC cases (6%), but they were present in 50% of appendicitis cases. Additionally, Candida isolates were recovered in 10% of NEC cases (0% of appendicitis group). These results indicate the unique bacteriology of peritonitis in the critically ill newborn and probably reflect abnormal colonization in the neonatal intensive care unit.