Etiology and antimicrobial resistance patterns in early and late neonatal sepsis in a Neonatal Intensive Care Unit.

Introduction: Neonatal sepsis is one of the main causes of death among newborn infants. Empirical antimicrobial treatment is based on epidemiological information and antimicrobial susceptibility tests. The objective of this study was to describe etiologic agents and their antimicrobial susceptibility among newborn infants with early-onset neonatal sepsis (EONS) or late-onset neonatal sepsis (LONS) at a Neonatal Intensive Care Unit.
Methods: Cross-sectional study conducted at a tertiary referral hospital in Western Mexico. Determination of antimicrobial resistance of microorganisms isolated in blood or cerebrospinal fluid of patients with EONS or nosocomial LONS.
Results: Yeasts and bacteria were isolated from 235 cultures corresponding to 67 events of EONS and 166 events of LONS. Of all isolates, the most common bacteria were Enterobacteriaceae (51.5%), followed by Streptococcus spp. in EONS, and by Staphylococcus spp. in LONS. Of all nosocomial Enterobacteriaceae, 40% were extended spectrum beta-lactamase producing bacteria. Among Staphylococcus species, resistance to oxacillin was recorded in 65.5%. Among Enterobacteriaceae (n: 121), resistance to amikacin, piperacillin-tazobactam, and meropenem was below 3%. Non-fermenting bacteria did not show resistance to amikacin, ciprofloxacin or cefepime; however, the number of isolates was scarce.
Conclusions: The most commonly identified bacteria in EONS were Enterobacteriaceae (67.6%) and Streptococcus spp. (17.6%), and Enterobacteriaceae (44.9%) and Staphylococcus spp. (34.7%) in LONS. Forty percent ofnosocomial Enterobacteriaceae were extended spectrum beta-lactamase producing bacteria, and 65.5% of Staphylococcus spp. showed resistance to oxacillin.