An outbreak of double carbapenemase-producing Klebsiella pneumoniae, harbouring NDM-5 and OXA-48 genes, at a tertiary hospital in Canberra, Australia

In July 2023, a carbapenemase-producing Klebsiella pneumoniae (CPKP) with New Delhi metallobeta-lactamase (NDM-5) and oxacillinase (OXA-48) carbapenemase genes was detected in the urine sample of a patient. A similar CPKP organism had previously been isolated from a surveillance rectal swab of an admitted patient, prompting an outbreak investigation. A confirmed case was defined as any suspected case in which a species of Enterobacterales was isolated from a clinical or surveillance specimen (infection or colonisation) exhibiting an NDM-5 or OXA-48 CPE gene or both, irrespective of phenotypic susceptibility. A descriptive epidemiological investigation was conducted to describe the investigation, infection prevention and control responses, and public health intervention carried out. Three confirmed cases of CPKP were identified, including the index case; 62 contacts were identified, of which 13 contacts were screened. CPKP transmission occurred between two patients on contact transmission-based precautions in separate single ensuite rooms. Despite being in the same ward, the patients did not share medical teams but shared nursing teams and ancillary staff. This study emphasises the importance of strict adherence to infection prevention and control practices and contact transmission-based precautions for patients admitted with carbapenemase-producing Enterobacterales.