ABSTRACT
The aim of this investigation was to measure the Postantifungal effect [PAFE] of 6 different oral Candida species following exposure to amphotericin B. Materials and Methods: Five oral isolates each of Candida albicans, Candida tropicalis, Candida krusel, Candida parapsilosis, Candida gla-brata and Candida guilliermondii [total of 30 isolates] were examined for the presence of PAFE after 1 h of exposure to the minimum inhibitory concentration of amphotericin B. The PAFE was determined as the difference in time [hours] required for the growth of the drug-free control and the drug-exposed test cultures to increase to 0.05 absorbance level following removal of amphotericin B. Results: The mean duration of amphotericin B-induced PAFE was lowest for C albicans [5.91 +/- 0.31 h] and greatest for C. parapsilosis [12.72 +/- 0.11 h], while C. guilliermondii [8.32 +/- 0.33 h], C. glabrata [8.43 +/- 0.21 h], C. krusel [9.68 +/- 0.23 h] and C. tropicalis [10.98 +/- 0.18 h] elicited intermediate values. Conclusion: Even a limited exposure to sublethal concentrations of amphotericin B suppressed growth of Candida species of oral origin. The significant variation in amphotericin B-induced PAFE amongst different Candida species may have clinical implications in terms of amphotericin B regimens used in the management Of Oral Candidiasis
ABSTRACT
To determine if D-xylose [XYL] and/or alpha-methyl-D-glucoside [MDG] assimilation can be used reliably as a rapid test to differentiate Candida dubliniensis from Candida albicans at an earlier time point such as 2 h after inoculation. Thirty isolates of C. albicans and C. dubliniensis recovered from anatomical sites and clinical specimens were used. Isolates were inoculated into the API 20C AUX yeast identification system, and incubated at 30[degree sign]C. XYL and MDG assimilations were read at 2-hour intervals beginning 2 h after the initial inoculation and up to 24 h of incubation; thereafter, results were read after 48 and 72 h. Twenty-nine [97%] C. albicans isolates had assimilated XYL at 16 h and, by 24 h, all isolates were positive for XYL assimilation. None of the C. dubliniensis isolates assimilated XYL. The MDG assimilation revealed that 24, 40, 92 and 100% of C. albicans isolates became positive after 16, 24, 48 and 72 h of incubation, respectively, whereas only 3% of C. dubliniensis isolates assimilated MDG after 72 h. The findings showed that it is possible to rapidly differentiate C. albicans from C. dubliniensis isolates using the API 20C AUX carbohydrate assimilation kits after 16 h of incubation at 30[degree sign] C based on the XYL assimilation