Selection of antimicrobial agents for treatment of neonatal sepsis

The incidence of sepsis among neonates born in the United States varies from less than one to more than eight per 1,000 live births. Bacterial meningitis occurs in about one-third of infants with sepsis and is more frequent during the first month of life than during any subsequent period. The clinical diagnosis of sepsis in newborn infants is difficult since signs are subtle and nonspecific. Because of the difficulty of diagnosis, many infants receive treatment although few significant bacterial infections are subsequently documents; approximately 5%-10% of neonates born in the United States receive parenteral antibiotics. The choice of antimicrobial agents for treatment of bacterial infections in neonates is based on knowledge of the responsible organisms and their patterns of antimicrobial susceptibility. Group B Streptococcus and Escherichia coli are currently the bacterial pathogens most often responsible for sepsis and meningitis in the United States. A penicillin and an aminoglycoside are the drugs usually used for initial therapy in infants with suspected sepsis. Present regimens are not optimal, however; mortality from sepsis and meningitis varies from 10% to 50%. Many survivors have significant sequelae. In addition, dose-related toxicity of the aminoglycosides is a concern. New beta-lactam antibiotics with increased efficacy against gram-negative enteric bacilli and with minimal or no dose-related toxicity warrant careful evaluation in newborn infants.