Bacteriological Profile and Antibiotic Susceptibility Patterns of Late-Onset Neonatal Sepsis in Levels III and IV Neonatal Intensive Care Units

Late-onset sepsis (LOS), which occurs 72 hours after birth, remains an important cause of mortality and morbidity in the neonatal intensive care unit (NICU). Differences in infant populations and the complexity of care at various NICU levels may result in varying bacteriological profiles and antibiotic susceptibility patterns. The objective of the current study was to determine and compare the bacteriological profiles, antibiotic susceptibility, and risk factors for LOS in levels III and IV NICU within a single hospital system. This was a retrospective study of infants with LOS and positive blood cultures, admitted to levels III and IV NICUs between 2012 and 2021. Of the 173 infants included in our study, 105 were admitted to the level IV NICU and 68 to the level III NICU. Infants in the level III NICU had a lower gestational age and birth weight at the time of LOS. Seventy percent of the infants had a central line. Gram-positive organisms were responsible for the vast majority of infections (75%), with coagulase-negative Staphylococcus (CoNS) being the most common bacteria in both units. Gram-negative bacteria were more frequently isolated from the level IV NICU (36.2%) compared to the level III NICU (8.8%). <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Enterobacter sp</i>. were the most frequently isolated gram-negative bacteria. All gram-positive bacteria were susceptible to vancomycin, and all gram-negative bacteria were susceptible to meropenem. The prevalent bacteriological profile and antibiotic susceptibility patterns in the NICU should guide the choice of empiric antibiotics for LOS. It is important to monitor sepsis and antimicrobial resistance patterns in the NICU and implement risk-specific strategies to reduce the burden of LOS. · LOS in NICUs is predominantly caused by gram-positive bacteria, mainly CoNS.. · Higher frequency of gram-negative bacteria, including E. coli and Enterobacter, in level IV NICU.. · All gram-negative isolates were meropenem-sensitive; vancomycin effective for gram-positives..