Nosocomial Transmission of New Delhi Metallo- β -Lactamase-1-Producing Klebsiella pneumoniae in Toronto, Canada

Design. An analysis of a cluster of New Delhi metallo-β-lactamase-1-producing Klebsiella pneumoniae (NDM1-Kp) and a retrospective case-cohort analysis of risk factors for acquisition in contacts of NDM1-Kp-positive patients.Setting. A 1,100-bed Canadian academic tertiary care center.Patients. Two index patients positive for NDM1-Kp as well as 45 contacts (roommates, ward mates, or environmental contacts) were investigated.Methods. Retrospective chart reviews of all patients colonized or infected with NDM1-Kp as well as contacts of these patients were performed in order to describe the epidemiology and impact of infection prevention and control measures. A case-cohort analysis was conducted investigating 45 contacts of NDM1-Kp-positive patients to determine risk factors for acquisition of NDM1-Kp. Rectal swabs were screened for NDM1-Kp using chromogenic agar. Presence of blaNDM-1 was confirmed by multiplex polymerase chain reaction. Clonality was assessed with pulsed-field gel electrophoresis (PFGE) using ...