Background: To describe two consecutive Serratia marcescens outbreaks in neonatology unit of Singapore General hospital and determine risk factors associated with its acquisition in the second outbreak.
Methods: Epidemiological investigations, environmental sampling and risk-factors analysis were used to guide infection control measures. Active surveillance sampling of nasopharyngeal aspirate and/or stool from neonates was conducted during both outbreaks. Whole-genome-sequencing was performed to determine clonal links. Retrospective case-control study was conducted in the second outbreak to identify risk factors for S. marcescens acquisition.
Results: In the one-year period in 2022, two S. marcescens outbreaks were managed involving five neonates in March 2022 outbreak and eight neonates in November 2022 outbreak. Both outbreaks were caused by genetically unrelated S. marcescens clones, with a link to positive isolates from sinks in intensive care units and milk preparation room during outbreak 1. Neonatal jaundice(OR, 16.46; p-value= 0.023) and non-formula milk feeding(OR, 13.88; p-value= 0.02) were identified as independent risk factors during second outbreak. Multiple interventions adopted were cohorting of positive cases, carriage-screening, enhanced environmental cleaning, and emphasis on alcohol-based handrubs for hand-hygiene.
Conclusion: The two outbreaks in our institution were likely due to infection prevention practices lapses and favourable environmental conditions. Nosocomial S. marcescens outbreaks in neonatology units are difficult to control and require multidisciplinary approach with strict infection prevention measures to mitigate infection risks.
Keywords: Outbreak; Serration marcescens; hospital; infection control; neonates; whole genome sequencing.
Copyright © 2024. Published by Elsevier Inc.