Molecular Identification of Clinically Common and Uncommon Yeast Species

Abstract

Background: The incidence of fungal infections caused by the yeasts and yeast-like species increased dramatically in immunocompromised patients, during the past several decades. However, a few of yeast and yeast-like species may colonize in skin and mucous membranes of healthy individuals. Objectives: The current study aimed at accurately identifying yeast and yeast-like species from clinical samples by molecular methods. Methods: A total of 1200 clinical samples were collected from patients with suspected fungal infection and 110 (9.16 %) yeast and yeast-like strains isolated and identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), PCR amplification of hwp1 gene, and sequencing. Results: In total, Candida albicans (n = 46) was the most frequently isolated species followed by C. parapsilosis complex (n = 17), C. tropicalis (n = 13), C. guilliermondii (n = 12), C. glabrata (n = 4), C. krusei and C. famata each (n = 3), C. kefyr, C. haemulonii and Cutaneotrichosporon jirovecii each (n = 2), and C. stellatoidea, C. intermedia, C. sorbosivorans, C. africana, Pichia kudriavzevii, and Trichosporon asahii each (n = 1). Interestingly, C. haemulonii, a multidrug resistant fungus was isolated from cutaneous and sputum samples for the first time in Iran. Conclusions: Nowadays, with growing population at risk for fungal infections and the emergence of some less virulent or non-pathogenic and uncommon yeasts not readily distinguishable with phenotypic assays, the accurate identification using molecular methods are warranted.