EARLY-ONSET NEONATAL SEPSIS: CHANGING ORGANISM PATTERNS BETWEEN 2003 AND 2014

BACKGROUND: Early-onset neonatal sepsis (EONS) is largely caused by vertical transmission of infectious organisms. The predominant pathogens causing EONS appear to be changing over time, however current prevention efforts focus on group B Streptococcus (GBS). Current and accurate characterization of the organism distribution in EONS is imperative to ensure effective antibiotic prophylaxis during labour and appropriate empiric treatment in neonates with suspected EONS. OBJECTIVES: The objective of this study was to evaluate trends in causative organisms of EONS. Congruent with recent reports, we hypothesized there would be an increase in EONS caused by Escherichia Coli. DESIGN/METHODS: Data was collected for infants admitted to neonatal intensive care units (NICU) participating in the Canadian Neonatal Network (CNN) from 2009 to 2014 with a positive blood or cerebrospinal fluid culture (CSF) within 72 hours of birth. Collected data was compared to previously published data on a cohort from 2003-2008 with the same case definition. The distribution of causative organisms over time was analyzed, as well as differences in causative organisms by gestational age grouping. RESULTS: Of the 87,374 NICU admissions between 2009-2014, 435 infants had positive blood and/or CSF culture resulting in an EONS incidence rate of 0.50%. The mean gestational age was 31.25.8 from 2009-2011 and 30.95.6 from 2012-2014, and was not significantly different between the two groups. From 2009-2011 and 2012-2014, E. coli was the causative organism in 40.2% and 46.0% of cases, respectively, and GBS was responsible for 26.3% and 25.1% of cases, respectively. Between 2003 and 2014, there was a significant trend of an increasing number of cases caused by E. coli (p<0.01), and a trend towards a decreasing number of cases due to GBS. EONS due to E. coli was more common among infants <37 weeks gestational age (GA), whereas GBS was the most likely causative organism among infants 37 weeks GA (p<0.01). CONCLUSION: Significant changes in the pattern of organisms causing EONS have important implications for both obstetric and neonatal healthcare providers. Careful surveillance of causative organisms is warranted to inform revisions to antibiotic prophylaxis and treatment guidelines.