CANDIDA TROPICALIS – A STUDY OF VIRULENCE FACTORS AND ANTIFUNGAL SUSCEPTIBILITY PROFILE OF THE CLINICAL ISOLATES OF AN EMERGING NON-ALBICANS CANDIDA SPP.

Dr. Elantamilan D. MD, *Dr. Wihiwot Valarie Lyngdoh MD, Dr. Annie Bakorlin Khyriem MD, Dr. Jyotismita Rajbongshi MBBS and Dr. Sneha Gupta MBBS

ABSTRACT

Introduction: Non-albicans Candida spp. (NAC) accounts for more than half of the cases of non-superficial Candida infections. Over the past two decades, there is a significant shift, showing increased isolation of non albicans Candida and Candida tropicalis is one of the commonest among NAC. In few studies, Candida tropicalis has superseded Candida albicans as the commonest cause of invasive Candidial infections. In this study we determined the virulence factors and antifungal susceptibility profile of the Candida tropicalis isolates obtained from clinical specimens. Methods and results: All the Candida tropicalis isolates were identified based on Corn-meal agar morphology, sugar assimilation test and CHROMagar. Biofilm formation (Tube method/48hr/2% safranin staining) was seen in 33.34% of the isolates. All the isolates (100%) elaborated esterase enzyme (Tween 80 hydrolysis test), hemolysin (Blood agar plate assay) and showed pseudohyphae formation. Hemolytic activity (Hz) and Esterase activity (Ez) were measured. The antifungal susceptibility of these isolates were determined using VITEK 2 system. The activity of fluconazole, voriconazole, caspofungin, micafungin, amphotericin B and flucytosine against the study isolates has been noted. Though all the studied isolates were susceptible to the above mentioned agents, the minimum inhibitory concentration of amphotericin B has been found to be increased (0.5μg/ml) in 44.44% of the isolates. Conclusion: The identification of virulence attributes and antifungal susceptibility profile of these isolates will aid in the understanding of the pathogenesis and better management of the infections caused by these organisms.

Keywords: Candida tropicalis, virulence factors, anti-fungal susceptibility, esterase, hemolytic activity.