<i>Klebsiella pneumoniae</i> Carbapenemase–Producing Enterobacterales Infection and Colonization in a Long-Term Care Facility — Ontario, Canada, May 2024–January 2025

The emergence of antibiotic-resistant organisms is a substantial public health concern because these organisms can cause severe, difficult-to-treat infections and spread easily in congregate settings. In January 2025, an outbreak of carbapenemase-producing Enterobacterales (CPE) infection and colonization was identified in a long-term care facility (LTCF) in Ontario, Canada, after a resident's urine culture grew Escherichia coli carrying the Klebsiella pneumoniae carbapenemase (KPC) gene. An investigation by the local public health agency in Windsor, Ontario, revealed that the source of infection was likely another patient with KPC-producing K. pneumoniae infection who had been admitted to the LTCF 1 year earlier without appropriate infection prevention and control precautions. The epidemiologic link between the two patients triggered unitwide screening. Three additional asymptomatic carriers who had not previously received CPE testing were identified during point-prevalence screening. All five affected residents were older adults with multiple comorbidities (including patients with frequent antibiotic use or an indwelling device such as a urinary catheter) who lived in the same unit and shared multiple potential exposure sources that likely contributed to the spread. Potential sources included overlapping staff member assignments, use of a common-area bathroom, and shared dining facilities. Whole genome sequencing confirmed the outbreak. Public health responses included rapid implementation of contact precautions, staff member cohorting, enhanced environmental cleaning, ensuring compliance with enhanced infection prevention and control practices, and risk communication with facility staff members, which halted further spread; evidence does not support the use of antimicrobials or other methods to decolonize asymptomatic CPE carriers. The outbreak highlighted the need for risk-based admission screening of LTCF residents, consistent infection-prevention practices, and antibiotic stewardship. Strengthening these practices can help prevent prolonged undetected transmission and reduce the incidence of CPE infection in congregate care settings.