Antimicrobial resistance patterns among urinary isolates from long-term care residents in Canada: findings from an AMRNet pilot

Background: Antimicrobial resistance is a growing concern in long-term care facilities (LTCs), where residents are often older, have chronic health conditions, and are frequently prescribed antimicrobials. Historically, antimicrobial resistance data from Canadian LTCs have been limited. This study explores the use of lab-based surveillance data from the Public Health Agency of Canada's AMRNet program to describe antimicrobial resistance in LTCs. Methods: Antimicrobial susceptibility data for clinical bacterial specimens were submitted from public and private laboratories across Canada. Where feasible, LTC patients were identified by submitting jurisdictions. Data on urinary isolates from identified LTC patients were analysed using the first isolate per patient per species per calendar year. The data were described by distribution of age group, sex, species and antimicrobial susceptibility. Antimicrobials were classified by the World Health Organization's 'Access, Watch and Reserve' (AWaRe) framework and a weighted-incidence syndromic combination antibiogram was constructed. As part of AMRNet program development, in some jurisdictions, only certain specimen types or organisms were submitted. Not all jurisdictions participated every year. Due to privacy precautions, some values rely on estimations. Results: From 2016-2024, AMRNet received data on 216,524 isolates from five provinces (BC, NL, ON, PEI, SK). Most isolates (98%) were from patients aged >=60, with those >=80 years representing 80%; females predominated across all age groups. Urine represented >99% of submitted data. The most common organisms identified from urinary isolates were Escherichia coli (51%), Klebsiella pneumoniae (14%) and Proteus mirabilis (12%). Non susceptibility varied across organisms: E. coli demonstrated higher non-susceptibility to several commonly used agents including fluoroquinolones (44%) and third generation cephalosporins (18%) while K. pneumoniae displayed high non-susceptibility to nitrofurantoin (56%). Among P. mirabilis, 26% were non susceptible to ciprofloxacin. Aminoglycoside and carbapenem resistance were low. When antimicrobials were grouped by WHO AWaRe categories, more than half of E. coli isolates were non-susceptible to at least one Watch antimicrobial. Interpretation: AMRNet lab-based surveillance data can help describe national AMR patterns among LTC residents. Although limitations exist and identifying LTC patients in lab-based datasets can be challenging in some jurisdictions, these data provide a feasible and cost-effective means of tracking national resistance trends among an at-risk population.