Evaluation of the effects of incubation temperature and pH on the susceptibility of Candida albicans isolates to ketoconazole invitro

ABSTRACT

Candidiasis, as an opportunistic infection, is caused by the Candida species. Although Candida albicans is classified in the body as an endogenic flora, it plays an important role in creating Candida related diseases. Candida vulvovaginitis in pregnant women, diabetes mellitus patients and those using multiple antibiotics and contraceptive drugs demonstrates the high resistance of the organism against conventional medication. On the other hand, recurrent vaginitis disintegrates the long-term process of treatment in majority of the patients. The present research was done with the aim of determining the optimum conditions for susceptibility testing before retreatment of patients. 10 isolates of Candida albicans obtained from 31 suspected patients suffering from recurrent Candida vaginitis were incubated with ketoconazole at two pH of 7.2 and 5.5 and two temperatures of 35°C and 27°C. The Microdilution broth test technique was used. The RPMI 1640 medium within the 96 well microplates with range of 12 tests was used to determine the MIC50, MIC90 and MFC of the drug. The obtained MIC50, MIC90 and MFC for ketoconazole at these conditions [T=35°C and pH=7.2] were 0.25 to 1 micro g/ml, 1 to 4 micro g/ml and 64 to >/= 512 micro g/ml respectively, while these values at 27°C, pH 5.5 were 1 to 8 micro g/ml, 8 to 64 micro g/ml and 512 to >/= 512 micro g/ml, at 35°C and pH 5.5 the values were 1 to 8 micro g/ml, 4 to 32 micro g/ml, 256 to >/= 512 micro g/ml, while at 27°C and pH 7.2 the values were 1 to 2 micro g/ml, 8 to 32 micro g/ml, 128 to >/= 512 micro g/ml, respectively. The obtained results confirmed that conditions with temperature of 35°C and pH 7.2 resulted in better treatment outcomes than other conditions