Emergence of Carbapenemase-Producing Enterobacteriaceae, South-Central Ontario, Canada1

Abstract

We analyzed population-based surveillance data from the Toronto Invasive Bacterial Diseases Network to describe carbapenemase-producing Enterobacteriaceae (CPE) infections during 2007-2015 in south-central Ontario, Canada. We reviewed patients' medical records and travel histories, analyzed microbiologic and clinical characteristics of CPE infections, and calculated incidence. Among 291 cases identified, New Delhi metallo-β-lactamase was the predominant carbapenemase (51%). The proportion of CPE-positive patients with prior admission to a hospital in Canada who had not received healthcare abroad or traveled to high-risk areas was 13% for patients with oxacillinase-48, 24% for patients with New Delhi metallo-β-lactamase, 55% for patients with Klebsiella pneumoniae carbapenemase, and 67% for patients with Verona integron-encoded metallo-β-lactamase. Incidence of CPE infection increased, reaching 0.33 cases/100,000 population in 2015. For a substantial proportion of patients, no healthcare abroad or high-risk travel could be established, suggesting CPE acquisition in Canada. Policy and practice changes are needed to mitigate nosocomial CPE transmission in hospitals in Canada.

Keywords: CPE; Canada; Ontario; antimicrobial resistance; bacteria; bacterial infections; beta-lactam resistance; carbapenem-resistant Enterobacteriaceae; drug resistance; incidence; population surveillance.

Figure 1

Incidence of all carbapenemase-producing enterobacterial infections per 100,000 inhabitants, 2007–2015 (A), and bloodstream infections per 100,000 inhabitants, 2010–2015 (B), calculated by using a Poisson regression model, Metropolitan Toronto and the Regional Municipality of Peel, south-central Ontario, Canada, 2007–2015. Shading indicates 95% CI.

Figure 2

Healthcare visits abroad and travel history in patients with carbapenemase-producing Enterobacteriaceae infection in the 1 year before detection, stratified by type of carbapenemase, Metropolitan Toronto and the Regional Municipality of Peel, south-central Ontario, Canada, 2007–2015. Patients who traveled to any location other than the Indian subcontinent were classified as low-risk travel and indicated as no high-risk travel in the graph. n values indicate number of patients. KPC, Klebsiella pneumoniae carbapenemase; NDM, New Delhi metallo-β-lactamase; OXA-48, oxacillinase 48; VIM, Verona integron-encoded metallo-β-lactamase.

Figure 3

Distribution of carbapenemases in 291 first isolates of carbapenemase-producing Enterobacteriaceae, by enterobacterial species (A) and region (B), Metropolitan Toronto and the Regional Municipality of Peel, south-central Ontario, Canada, 2007–2015. Other enterobacterial species were Serratia marcescens (n = 4), Klebsiella oxytoca (n = 3), Providencia rettgeri (n = 1), and Proteus mirabilis (n =1). Other carbapenemases or co-productions were NDM–OXA-48 (n = 2) and S. marcescens enzyme (n = 1). KPC, Klebsiella pneumoniae carbapenemase; NDM, New Delhi metallo-β-lactamase; OXA-48, oxacillinase 48; VIM, Verona integron-encoded metallo-β-lactamase.