The impact of group B streptococcus prophylaxis on late-onset neonatal infections

Objective: To determine trends in late-onset neonatal infections and risk factors for ampicillin/penicillin-resistant microorganisms. Study Design: Data on 584 infants with positive blood, urine or cerebrospinal fluid cultures for bacteria or fungi at 8-30 days of age from 1990 to 2007 were examined and divided into three epochs, based on intrapartum antibiotic prophylactic (IAP) practices. Pathogens and antibiotic resistance were compared among epochs. Result: The number of candidal infections increased over time for the entire population (P=0.006). There was an increased incidence of Gram-negative (P=0.009) and candidal infections (P=0.014) among very low-birthweight infants. Only Escherichia coli infections showed increasing ampicillin resistance over epochs (P=0.006). In regression analysis, ampicillin/penicillin resistance increased with IAP use (odds ratio 2.05). Conclusion: Changing microorganisms and increasing antibiotic resistance in late-onset neonatal infections are likely multifactorial but are increased with IAP use, which may identify an at-risk population. Increasing Candida infections require further investigation.