Aim. To prospect for mixed cultures of Candida spp. in oral samples and to assess their antifungal susceptibilities with respect to a possible relapse of infection due to proliferation of the coexistent species usually not considered in routine laboratory practice.

Material and method. 53 oropharyngeal samples were included in the study. For isolation and identification, the colony appearance on Chromagar Candida medium (Becton Dickinson, USA), chlamidospores production and substrate assimilation profiles based on API 20 C Aux system were used. The antifungal susceptibility was assessed using Etest method (AB Biodisk, Solna, Sweden) for fluconazole and ATB Fungus (bioMérieux, France) for nistatine, miconazole, econazole, ketoconazole, amphotericine B and 5-flucytosine.

Results. 8 from 53 samples (15%) represented mixed cultures (4 double and 4 triple). Colonies numbering on primary isolation plate was used to consider the species causing the infection and the coexisting species as well. In these samples the dominant species were Candida albicans in 7 cases and Candida glabrata in 1 case. The coexistent species (C. krusei, C. norvegensis, C. lusitaniae) were more resistant to antifungal agents than the main species C. albicans. By chance, in one sample, two different strains of C. albicans were identified by means of susceptibility patterns to antifungals.

Discussions. Two or more Candida isolates with major susceptibility differences, could coexist in one sample. Species of Candida less susceptible could be easily selected after antifungal treatment if the coexisting species is not considered. The use of chromogenic media could be the key for the management of oral candidosis.