Abstract
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%). Escherichia coli (E. coli) and Enterobacter sp. 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.
Key Points
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LOS in NICUs is predominantly caused by gram-positive bacteria, mainly CoNS.
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Higher frequency of gram-negative bacteria, including E. coli and Enterobacter, in level IV NICU.
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All gram-negative isolates were meropenem-sensitive; vancomycin effective for gram-positives.
Keywords
late-onset sepsis - antibiotic susceptibility - neonates