Identification and antifungal susceptibility testing of some candida Spp. strains using modern phenotypic methods

Abstract

The aim of this study was to identify Candida isolates from animals and humans using VITEK 2 card system, a modern phenotypic method testing 64 biochemical characters and the susceptibility testing using MIC method on the same Vitek 2, for 6 modern antifungals. The research was conducted during January-June 2016 in the Department of Microbiology, Faculty of Veterinary Medicine in Cluj-Napoca. Identification was made from 48 hrs isolated colonies, preparing a suspension of 1.8-2.2 optical density, and 280μl were substracted and transferred over in saline for susceptibility testing. After a period of 18-19 hours for analysis of 64 biochemical characters for each tested strain, the results were saved/printed as Laboratory report in PDF format. From the total of 20 tested strains, six were represented by Candida albicans, five strains were identified as Candida krusei, 3 were Candida tropicalis 2 Candida catenulata 2 Candida parapsilosis and other two Cryptococcus laurentii. Most identified species are susceptible to micafungin with MIC ranging from 0.06 and 0.12 depending on the species, except for Candida parapsilosis. Voriconazole was also very efficient, with MIC value of 0.12 for almost all identified species. Caspofungin efficiency is specie-related, so for C. albicans and C. tropicalis MIC is 0.25, for C. krusei is 0.5 and for C. catenulata and C. parapsilosis MIC equals 1. Flucytosine has a constant value of 1 in all identified species, except for C. krusei with MIC value of 4 or 8 - resistant strains.