PC1127: Antibiotic Management in the Neonatal Intensive Care Unit

Background: Neonatal sepsis is a life-threatening emergency contributing to neonatal mortality. Adequate empiric antibiotic therapy can minimize morbidity and mortality. We sought to evaluate the epidemiology and potential resistance of pathogens in the NICU over a 10-year period. Our objective was to identify the most common organisms and susceptibilities to optimize antibiotic management.

Methods: This retrospective cohort study included neonates admitted to a level III NICU from 2011-2020. Neonates treated for an infection with a corresponding positive culture (blood, urine, respiratory, or cerebrospinal fluid) were included in the study. Neonates who had cultures identified as contaminants were excluded. The primary endpoint was to determine the prevalence of common organisms and resistance patterns. Secondary endpoints included evaluating risk factors for more resistant organisms, including time onset of sepsis (early vs. late), gestational age (very preterm ( < 30 weeks), preterm (31-36 weeks), and term infants (>37 weeks), mode of delivery, concomitant diseases and presence of central lines.

Results: A total of 183 positive cultures were identified in 156 patients over the course of 10 years. Of the 183 cultures, a majority of the cultures occurred in very preterm infants (n=144, 78.6%). The prevalence of common organisms are depicted in Table 1 and did not differ based on gestational age. An increase in the prevalence of Klebsiella pneumonia is observed and 93% occured in very preterm neonates. A majority of strains (n=14, 87.5%) required cefazolin for treatment. The most common organisms in early onset sepsis (EOS) were E. coli (n=14, 40%) followed by Group B Streptococcus (n=6, 17%). The most common organisms causing late onset sepsis (LOS) included Staphylococcus epidermidis (n=45, 30%) and Staphylococcus aureus (n=39, 26%). In the overall and very preterm population, 80% and 71%, respectively of the Staphylococcus aureus strains were oxacillin susceptible. Staphylococcus epidermidis was penicillin or oxacillin sensitive in 13% of the cases. E. coli was the most common Gram-negative organism and susceptible to ampicillin overall and in very preterm infants 38% and 14% of cases, respectively. Cephalosporin use was necessary for 32 cultures. Sixteen cultures required carbapenems, 15 strains of organisms producing amp-C (Citrobacter, Enterobacter, and Serratia) and one extended spectrum producing strain of E. coli. A majority of these resistant organisms occurred in patients that were very preterm (n=14, 88%).

Conclusion: The most common organisms remained similar with an increasing trend in the prevalence of K. pneumoniae over the study period. Due to the rates of resistance with S.epidermidis to penicillin, LOS empiric therapies should continue to incorporate vancomycin in our institution. The rates of ampicillin resistant E. coli and K. pneumoniae, there is an increasing need to potentially identify opportunities for incorporating cephalosporins for empiric therapy.