title: Change in antimicrobial susceptibility of  Escherichia coli  urinary tract isolates at a single institution over a period of 10 years.
abstract: Urinary tract infections are common. Few published studies have demonstrated the change in Escherichia coli urinary isolate antimicrobial susceptibility over time within a given area and (or) population. The purpose of this study was to evaluate the change in susceptibility of E. coli clinical isolates obtained from urine specimens at a single institution over a period of 10 years. The microbiology laboratory information system at St. Boniface Hospital (Winnipeg, Manitoba, Canada) was searched retrospectively from 1 January 2000 to 31 December 2009, for all E. coli isolates from either a midstream or catheter urine source that had susceptibility testing performed. Only one isolate per patient was included during the entire study period. Antimicrobial susceptibility testing was carried out with either a Microscan instrument (pre-April 2004) or a Vitek instrument (May 2004 onwards). In total, 7353 E. coli urinary isolates were included for evaluation. Ciprofloxacin susceptibility declined significantly, from 99% in 2000 to 85% in 2009 (p < 0.0001). A small but statistically significant decline in susceptibility was also observed for ampicillin, cefazolin, trimethoprim-sulfamethoxazole, gentamicin, and nitrofurantoin. These data suggest that certain antimicrobials recommended for the treatment of urinary tract infections (ciprofloxacin, trimethoprim-sulfamethoxazole) may no longer be optimal.
authors.affiliation: Departments of Medicine and Clinical Microbiology, Health Sciences Centre, MS673B-820 Sherbrook Street, Winnipeg, MB R3A 1R9, Canada. awalkty@mts.net
authors.forename: A
authors.initials: A
authors.lastname: Walkty
authors.forename: P R S
authors.initials: PR
authors.lastname: Lagacé-Wiens
authors.forename: J A
authors.initials: JA
authors.lastname: Karlowsky
authors.forename: D J
authors.initials: DJ
authors.lastname: Hoban
authors.forename: K
authors.initials: K
authors.lastname: Manickam
authors.forename: H
authors.initials: H
authors.lastname: Adam
authors.forename: P
authors.initials: P
authors.lastname: Pieroni
authors.forename: M
authors.initials: M
authors.lastname: Alfa
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D006801:Humans; D008350:Manitoba; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D014552:Urinary Tract Infections / Q000382:microbiology*; D014556:Urine / Q000382:microbiology
chemical_list: D000890:Anti-Infective Agents