Examining the impact and response to an outbreak of carbapenemase-producing Enterobacterales in a neonatal unit in the United Kingdom: An outbreak report

Background: Carbapenemase-producing Enterobacterales (CPE) are a group of Gram-negative bacteria causing global concern due to their resistance to carbapenems. In this report, we detail the learning points from a CPE outbreak in a tertiary neonatal unit (NU) in the UK. Methods: Routine surveillance screening (rectal swabs) of babies on the NU identified a potential cluster of CPE carriage. Samples were sent to a reference laboratory for confirmatory testing. Environmental screening and cot mapping were undertaken to determine movements of babies within the unit. Regular audits of cleaning standards, hand hygiene, and maternal hygiene when expressing breast milk were carried out. Results: The outbreak lasted 19 weeks. During the outbreak, there were 360 admissions, with 11 babies being colonised with the outbreak strain. Once the outbreak was declared, there were enhanced Infection Prevention and Control (IPC) precautions (including increased environmental and equipment cleaning frequency). CPE screening frequency was increased and cot capacity was reduced. Hand hygiene compliance improved from 92% at the start of the outbreak to 100% by its close. Cleaning standards remained compliant. Maternal hygiene standards varied from 78% to 100%, but no cross-infection links were identified. Environmental screening was negative. No route of cross-infection was identified. Notably, no babies developed invasive CPE infection. Conclusion: This is the first report of a CPE outbreak in a UK NU. Although no specific mode of cross-transmission was identified and the outbreak's end cannot be attributed to any single intervention, the bundle of interventions proved successful after a 5-month period.