Molecular epidemiological analysis of a suspected nosocomial outbreak of carbapenem-resistant Klebsiella aerogenes

Objectives Carbapenem-resistant Enterobacterales (CRE) are a common source of healthcare-associated infections and nosocomial outbreaks. We examined a suspected nosocomial outbreak of carbapenem-resistant Klebsiella aerogenes in a surgical ward over a period of 11 months. Methods We used whole-genome sequencing (WGS) to assess the genetic relatedness of eight detected isolates. Results Molecular epidemiological analyses confirmed the outbreak as a pseudo-outbreak. During the period of assessment, the hospital infection control team implemented multiple interventions to promote stringent hand hygiene compliance, appropriate use of personal protective equipment, and adherence to best practices for wound care and body fluid management. Despite these measures, intermittent CRE isolation continued. Notably, WGS analyses revealed that all assessed isolates were genetically unique, with no evidence to indicate clonal relatedness. Conclusions The suspected nosocomial outbreak comprised sporadic unrelated cases of CRE. Our findings in this study highlight the significance of molecular epidemiological tools in precisely evaluating suspected outbreaks of CRE and in directing the effective deployment of infection control resources.