SPECIES IDENTIFICATION, ANTIFUNGAL SUSCEPTIBILITY TESTING AND GENETIC VARIABILITY AMONG CANDIDA SPECIES ISOLATED FROM CLINICAL SAMPLES

Abstract

Candida albicans is an opportunistic pathogen that usually lives as commensal in the healthy human host. The most common infecting species is C. albicans where as other non albicans species are C. glabrata, C. parapsilosis, C. tropicalis and C. krusei that also causes various clinical diseases. Candidemia is the fourth leading cause of bloodstream infections and carries a 35–55% mortality. There is increase in the incidence of candidiasis cases has also been reported in immunocompromised individuals associated with non albicans species, such as C. glabrata, C. krusei, C. tropicalis and C. parapsilosis. The main risk factors are Invasive candidiasis, urinary candidiasis, gastrointestinal candidiasis, respiratory candidiasis and vulvo-vaginal candidiasis. MATERIAL AND METHOD: A total of 30 samples were collected from zonal hospital Solan (H.P) India and college students of SILB Solan. Candida species were isolated from 24 samples, 6 samples were found negative. Samples were further identified on the basis of phenotypic characteristics such as Germ tube test, pseudohyphae production, Chlamydospore production, morphology on CHROM agar, sugar fermentation test and sugar assimilation test. Antifungal susceptibility testing of the Candida isolates were done against amphotericin B and voriconazole. Fifty percent of the isolates were found resistant to voriconaazole, whereas, 60% were resistant to amphotericin B. However 13% isolates were found semi dose dependent to amphotericin B. Genetic variability of highly resistant Candida species i.e. Candida tropicalis (H1 and H15), Candida albicans (H2 and H8) and Candida glabrata (H6) was done by RFLP using Eco RI enzyme. In case of Candida tropicalis isolates (H1 and H15) band patterns were similar, but in case of Candida albicans (H2 and H8) the band patterns generated were dissimilar. This showed that Candida albicans from Solan geographical region showed genetic variability.

KEYWORDS: C. parapsilosis, C. tropicalis, C. krusei and C. glabrata