Fecal bacterial microflora of newborn infants during intensive care management and treatment with five antibiotic regimens.

Aerobic and anaerobic fecal bacterial flora of normal newborn infants, of preterm newborn infants without other health problems and of five groups of newborn infants treated with combinations of benzylpenicillin, cloxacillin, flucloxacillin, ampicillin, cefuroxime, cefoxitin and gentamicin were compared. Preterm birth alone was associated with growth of Klebsiella which could be attributed to a higher rate of cesarean section in preterm than in term infants. All antibiotic regimens led to a pronounced suppression of anaerobic flora and overgrowth of Klebsiella but not with other gram-negative aerobic bacteria. A slight colonization with Clostridium difficile and Clostridium perfringens occurred. Disturbances of the intestinal microbial ecology can be expected in newborn infants after preterm birth by cesarean section and/or treatment with antibiotics, including some penicillins that are usually regarded as relatively harmless in this respect in adults.