title: Trimethoprim/sulfamethoxazole resistance in clinical isolates of Burkholderia pseudomallei.
abstract: OBJECTIVE
  Trimethoprim/sulfamethoxazole is commonly used to treat melioidosis. Antimicrobial susceptibility testing using the disc diffusion method is commonly used in melioidosis-endemic areas, but may overestimate resistance to trimethoprim/sulfamethoxazole.
  
  
  METHODS
  We performed disc diffusion and Etest on isolates from the first positive culture for all patients presenting to Sappasithiprasong Hospital, Ubon Ratchathani, Thailand, with culture-confirmed melioidosis between 1992 and 2003.
  
  
  RESULTS
  The estimated resistance rate for 1976 clinical Burkholderia pseudomallei isolates was 13% by Etest and 71% by disc diffusion. All isolates classed as either susceptible (n=358) or as having intermediate resistance (n=218) on disc diffusion were susceptible by Etest. Only 258 of the 1400 (18%) isolates classed as resistant on disc diffusion were resistant by Etest.
  
  
  CONCLUSIONS
  Disc diffusion testing of B. pseudomallei may be useful as a limited screening tool in resource poor settings. Isolates assigned as 'susceptible' or 'intermediate' by disc diffusion may be viewed as 'susceptible'; those assigned as 'resistant' require further evaluation by MIC methodology.
authors.affiliation: Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: Vanaporn
authors.initials: V
authors.lastname: Wuthiekanun
authors.forename: Allen C
authors.initials: AC
authors.lastname: Cheng
authors.forename: Wirongrong
authors.initials: W
authors.lastname: Chierakul
authors.forename: Premjit
authors.initials: P
authors.lastname: Amornchai
authors.forename: Direk
authors.initials: D
authors.lastname: Limmathurotsakul
authors.forename: Wipada
authors.initials: W
authors.lastname: Chaowagul
authors.forename: Andrew J H
authors.initials: AJ
authors.lastname: Simpson
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Short
authors.forename: Gumphol
authors.initials: G
authors.lastname: Wongsuvan
authors.forename: Bina
authors.initials: B
authors.lastname: Maharjan
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: White
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D016957:Burkholderia pseudomallei / Q000187:drug effects*; D004058:Diffusion; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D015662:Trimethoprim, Sulfamethoxazole Drug Combination