Phenotyping and genstyping of clinical isolates of Candida species

ABSTRACT

Candida species are the most common cause of fungal infections in hospitalized patients. Clinical Candida isolates were collected from Zagazig and Benha University Hospitals. The isolates were subjected for rapid identification arid differentiation of the clinically important Candida species on Oxoid Chromogenic Candida Agar [OCCA] medium. On the basis of colony pigmentation on OCCA, 131 yeast isolates were correctly identified. The results revealed a relative reduction in rates of infection caused by Candida albicans and a shift toward non-albicans Candida species. Candida krusei and Candida glabrata were the most common isolates [46 isolates of each species, 35.1%] followed by Candida albicans, 32 isolate [24.4%] and Candida tropicalis 7[5.3%]. The susceptibility of the clinical isolates to the different antifungal agents was performed on Mueller-Hinton agar by disk diffusion method. The results showed that, 25[19.1%], 47[35.9%], 49[37.4%] and 32[24.4%] of the isolates were resistant to amphotericin B, fluconazole, voriconazole, and terbinafine; respectively. The resistance of clinical isolates was furtherly confirmed by determination of their MlCs by agar dilution method. Candida isolates of each species were genotyped by Random Amplification of Polymorphic DNA [RAPD] assay. In which the genetic relatedness of the isolates were evaluated by Polymerase Chain Reaction [PCR]. Genetic fingerprinting patterns [Fig 2] were determined and summarized in Tables [2-8]. The data presented in these tables revealed that, there is no significant genetic relatedness among the isolates of each Candida species. In conclusion: The present study identified the more spread of non-albicans Candida species of Zagazig and Benha University Hospitals than the Candida albicans species, but identified no one of these isolates having nosocomial characteristics