New Delhi metallo-β-lactamase-1 -producing Klebsiella oxytoca sequence type 2 from toilets as the likely source of nosocomial transmission to patients – a root cause analysis
Year: 2025
Type: article
Abstract: The hospital environment is a known reservoir for nosocomial infections, with bathroom plumbing increasingly implicated in the spread of carbapenemase-producing Enterobacterales (CPE). At Aalborg University Hospital (AUH), Denmark, two ongoing outbreaks of CPE have been linked to Citrobacter freundii sequence type 18 (ST18) and Klebsiella oxytoca ST2. While both outbreak strains carry a bla NDM-1 gene on distinct plasmids, the role of bathroom fixtures in their transmission to patients remains unclear. This study aims to investigate the environmental reservoirs and potential transmission routes of New Delhi metallo-β-lactamase-1 (NDM-1)-producing K. oxytoca isolates associated with patients and the environment within the Gastric Surgery Unit (GSU) at AUH. Weekly rectal swabs were conducted on GSU patients, accompanied by environmental sampling at two timepoints of toilets, drains, and dry surfaces over a 450-day period. Whole-genome sequencing and plasmid analysis were used to assess genetic relationships between environmental and patient isolates. Additional targeted environmental screenings focused on bathrooms in high-risk rooms. NDM-1-producing K. oxytoca ST2 was consistently detected in three toilets, each harbouring distinct genomic sub-clades. Four patients were later found colonized with isolates genetically related to those from the toilets. No evidence of direct patient-to-patient transmission was found, underscoring the role of toilets as reservoirs in the outbreak. Temporal data relating to the various samples suggest that the environmental reservoirs in two specific bathrooms, and presumably their toilets, are the most likely sources of transmission to the four patients at the GSU.
Source: Infection Prevention in Practice
Authors: H.D. Eriksen, L.J. Porsbo, B. Bang, N. Ank, H. Hasman
Institutions: Aalborg University Hospital, Statens Serum Institut
Language: English
Subfield: Molecular Medicine
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $1,500
OpenAlex ID: W4415024763