title: Impact of pH on the antifungal susceptibility of vaginal Candida albicans.
abstract: OBJECTIVE
  To investigate the antifungal susceptibility at pH 7.0 and pH 4.0 of 5 antifungal agents against Candida albicans isolated from patients with vulvovaginal candidiasis.
  
  
  METHODS
  Antifungal susceptibility testing at pH 7.0 and pH 4.0 was performed using the broth microdilution method (CLSI, document M27-A2).
  
  
  RESULTS
  The minimal inhibitory concentrations (MICs) of miconazole, clotrimazole, fluconazole, and nystatin against C. albicans at pH 4.0 were significantly higher than those at pH 7.0 (0.25 vs 0.03 μg/mL, 0.50 vs 0.03 μg/mL, 0.50 vs 0.25 μg/mL, and 32 vs 2 μg/mL, respectively; P<0.001), whereas the MIC of itraconazole at pH 4.0 was lower than that at pH 7.0 (0.030 vs 0.125 μg/mL; P<0.001). The susceptibility rate of C. albicans to itraconazole at pH 4.0 was significantly higher than at pH 7.0 (95.0% vs 51.7%; P<0.001). The susceptibility rate to itraconazole at pH 7.0 was significantly lower than the susceptibility rate to fluconazole (51.7% vs 100.0%; P<0.001), whereas the susceptibility rates to the 2 drugs were similar at pH 4.0 (95.0% and 96.7%, respectively).
  
  
  CONCLUSIONS
  Media at different pH values should be used for sensitivity tests according to the environment of C. albicans.
authors.affiliation: Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Luo
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D014621:Vagina / Q000382:microbiology
chemical_list: D000935:Antifungal Agents