Neonatal early-onset sepsis: A changing paradigm of pathogens and high-risk cohorts.

The causative pathogens of neonatal early-onset sepsis (EOS) have changed over time with a shift towards gram-negative organisms. This change is likely multifactorial and due in part to a high prevalence of maternal intrapartum antibiotic exposure leading to alterations in rectovaginal colonization with antibiotic-resistant organisms and subsequent neonatal colonization and infection. As a result, neonatal EOS secondary to gram-negative pathogens, particularly Escherichia coli (E. coli), is becoming more aggressive, resistant and difficult to treat, and not exclusive to very low birth weight infants with more EOS emerging in late preterm and term infants. Therefore, a heightened awareness regarding the dangers of resistant bacterial infections in neonates is critical, as well as a reevaluation of current maternal and neonatal surveillance and prevention efforts.