title: Antimicrobial resistance in urinary tract pathogens in Canada from 2007 to 2009: CANWARD surveillance study.
abstract: From January 2007 to December 2009, an annual Canadian national surveillance study (CANWARD) tested 2,943 urinary culture pathogens for antimicrobial susceptibilities according to Clinical and Laboratory Standards Institute guidelines. The most frequently isolated urinary pathogens were as follows (number of isolates, percentage of all isolates): Escherichia coli (1,581, 54%), enterococci (410, 14%), Klebsiella pneumoniae (274, 9%), Proteus mirabilis (122, 4%), Pseudomonas aeruginosa (100, 3%), and Staphylococcus aureus (80, 3%). The rates of susceptibility to trimethoprim-sulfamethoxazole (SXT) were 78, 86, 84, and 93%, respectively, for E. coli, K. pneumoniae, P. mirabilis, and S. aureus. The rates of susceptibility to nitrofurantoin were 96, 97, 33, and 100%, respectively, for E. coli, enterococci, K. pneumoniae, and S. aureus. The rates of susceptibility to ciprofloxacin were 81, 40, 86, 81, 66, and 41%, respectively, for E. coli, enterococci, K. pneumoniae, P. mirabilis, P. aeruginosa, and S. aureus. Statistical analysis of resistance rates (resistant plus intermediate isolates) by year for E. coli over the 3-year study period demonstrated that increased resistance rates occurred only for amoxicillin-clavulanate (from 1.8 to 6.6%; P < 0.001) and for SXT (from 18.6 to 24.3%; P = 0.02). For isolates of E. coli, in a multivariate logistic regression model, hospital location was independently associated with resistance to ciprofloxacin (P = 0.026) with higher rates of resistance observed in inpatient areas (medical, surgical, and intensive care unit wards). Increased age was also associated with resistance to ciprofloxacin (P < 0.001) and with resistance to two or more commonly prescribed oral agents (amoxicillin-clavulanate, ciprofloxacin, nitrofurantoin, and SXT) (P = 0.005). We conclude that frequently prescribed empirical agents for urinary tract infections, such as SXT and ciprofloxacin, demonstrate lowered in vitro susceptibilities when tested against recent clinical isolates.
authors.affiliation: Diagnostic Services of Manitoba/Department of Clinical Microbiology, Health Sciences Centre, St Boniface General Hospital, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada. jkarlowsky@hsc.mb.ca
authors.forename: James A
authors.initials: JA
authors.lastname: Karlowsky
authors.forename: Philippe R S
authors.initials: PR
authors.lastname: Lagacé-Wiens
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Simner
authors.forename: Melanie R
authors.initials: MR
authors.lastname: DeCorby
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Adam
authors.forename: Andrew
authors.initials: A
authors.lastname: Walkty
authors.forename: Daryl J
authors.initials: DJ
authors.lastname: Hoban
authors.forename: George G
authors.initials: GG
authors.lastname: Zhanel
mesh_terms: D000293:Adolescent; D000328:Adult; D000658:Amoxicillin / Q000494:pharmacology / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D002170:Canada; D002939:Ciprofloxacin / Q000494:pharmacology / Q000627:therapeutic use; D019818:Clavulanic Acid / Q000494:pharmacology / Q000627:therapeutic use; D004926:Escherichia coli / Q000187:drug effects / Q000472:pathogenicity; D005260:Female; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000472:pathogenicity; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011513:Proteus mirabilis / Q000187:drug effects / Q000472:pathogenicity; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000472:pathogenicity; D013211:Staphylococcus aureus / Q000187:drug effects / Q000472:pathogenicity; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology / Q000627:therapeutic use; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000382:microbiology*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D019818:Clavulanic Acid; D002939:Ciprofloxacin; D000658:Amoxicillin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination