Speciation, biofilm formation and antifungal susceptibility of Candida isolates

Abstract

DOI Link: http://dx.doi.org/10.21276/IJRDPL. 2278-0238.2017.6(2).2517-2521 Abstract: Recently, an increase in the incidence of infections caused by fungi especially non-albicans Candida species has been reported. Several virulence factors like biofilm formation, toxin production and presence of adhesins contribute to its pathogenesis. This study was undertaken to determine species distribution, biofilm formation and in-vitro antifungal susceptibility of Candida isolated in our tertiary care hospital. One hundred and forty-two clinical isolates obtained from various clinical specimens were subjected to KOH smear and cultured on Sabouraud’s Dextrose agar medium. Conventional methods and automated identification system (Vitek 2 Compact) for yeast identification were done. Biofilm forming ability of each isolate was detected using microtitre plate method. Antifungal susceptibility against fluconazole, voriconazole, flucytosine, amphotericin B and caspofungin was tested using Vitek 2 Compact. Out of 142 Candida isolates, 90 (63.4%) were C. albicans and 52 (36.6%) were non-albicans Candida species. Among 52 nonalbicans Candida, C. parapsilosis was found in 20 (38.5%) cases followed by C. tropicalis 16 (30.8%). Among all isolates, 52 (36.6%) were biofilm producers and biofilm positivity was more among non-albicans Candida 28 (53.8%) as compared to C. albicans 24 (26.7%) (p-value <0.002). The maximum positivity was observed with isolates from plastic devices (60%). The minimum inhibitory concentrations of all isolates against antifungal drugs were within susceptible range. Although C. albicans remains the major isolate from various clinical specimens, infections caused by non-albicans. Candida is on the rise and biofilm formation as a virulence factor might have a higher significance for nonalbicans Candida species than for C. albicans. The changing epidemiology of Candida infections highlights the need for close monitoring on the distribution, biofilm production and susceptibility to optimize therapy and outcome. ⇑ Corresponding authors at: Dr. Shilpa Arora, Department of Microbiology, Guru Gobind Singh Medical College & Hospital, Faridkot, India E-mail address: s.arora49@yahoo.com, drnitikadhuria@gmail.com, neerjarajender@hotmail.com, shipragalhotra@gmail.com