title: Transferable high-level trimethoprim resistance among isolates of Escherichia coli from urinary tract infections in Ontario, Canada.
abstract: Of 1171 isolates of Escherichia coli isolated from urine samples at the Public Health Laboratory, Toronto, Ontario, Canada, between May 1990 and December 1991, 120 (10.3%) were resistant to trimethoprim (TMP), cotrimoxazole (TMP/SMX), sulfamethoxazole (SMX) and other antimicrobial agents; 110 of the 120 isolates (91.7%) were resistant to four or more agents. The majority of resistant isolates (91.7%) exhibited high-level resistance (MIC > 1000 mg/L) to TMP. The MIC of TMP/SMX for all 120 isolates was > 2.0/38.0 mg/L and for SMX > 1024 mg/L. High-level resistances were also present among the beta-lactam antimicrobials with MICs ranging from 16- > 256 mg/L. Forty-three of 120 TMP-resistant (35.8%) isolates conjugally transferred TMP-resistance to E. coli K-12. Co-transfer of several other resistances was observed. SMX cotransferred from 86% of the 43 donors and beta-lactams together with SMX cotransferred from 70%. Nalidixic acid resistance was present among 22 (18.3%) of the 120 resistant isolates, however, nalidixic acid resistance was not transferred to E. coli K-12.
authors: Clinical Bacteriology Section, Central Public Health Laboratory, Toronto, Ontario, Canada.
authors: N
authors: N
authors: Harnett
mesh_terms: D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008826:Microbial Sensitivity Tests; D009864:Ontario / Q000453:epidemiology; D014161:Transduction, Genetic; D014296:Trimethoprim Resistance / Q000235:genetics; D014552:Urinary Tract Infections / Q000453:epidemiology / Q000382:microbiology*