Post-antifungal effect of polyene, azole and DNA-analogue agents against oral Candida albicans and Candida tropicalis isolates in HIV disease.

Oropharyngeal candidiasis (OPC) is the most frequent AIDS-associated opportunistic infection, as up to 90% of HIV-infected individuals suffer at least one episode during the course of their disease. Various in vivo and in vitro procedures have been used to assess the effectiveness of antifungal agents used in HIV infection. In the present study, we evaluated in vitro the minimum inhibitory concentration (MIC) and the post-antifungal effect (PAFE) of two polyenes, two azoles and one DNA-analogue against 10 oral isolates of Candida albicans and 10 of Candida tropicalis, all from HIV-infected individuals, in order to obtain basic data on the pharmacodynamics of these drugs. One-hour exposure to twice the MIC of all the drugs, except fluconazole, elicited a consistently high PAFE in both Candida species. Furthermore, the PAFE elicited by the antifungals (except fluconazole) was significantly prolonged for C. tropicalis compared with C. albicans. This speedy recovery of C. albicans isolates exposed to transient low concentrations of antifungals appeared to reflect its virulence compared with lesser potent species, such as C. tropicalis. Taken together, the current data, while confirming the existence of PAFE in a non-albicans species of Candida, also provide further clues for the recalcitrance of C. albicans species in the face of antifungal therapy for oropharyngeal candidiasis.