Emergence of non-Candida albicans species: Epidemiology, phylogeny and fluconazole susceptibility profile

Abstract

Objective: Non-Candida albicans (NCA) species now account for a significant part of clinical candidiasis worldwide. In the present study, epidemiology and antifungal susceptibility profile of NCA isolated from various forms of candidiasis were studied with special focus on their phylogenetic relationship by ITS sequencing.

Patients and methods: Seventy-nine NCA isolates were isolated from skin and nail scrapings (67.0%), vaginal discharges (8.8%), blood (8.8%), sputa (5.0%), urine (5.0%), oral swabs (2.6%), biopsy and eye tumor, each (1.4%). These isolates were identified by morphological, biochemical and molecular (ITS sequencing) techniques. In vitro antifungal susceptibility of the isolates to fluconazole (FCZ) was tested according to the CLSI method (M27-S4).

Results: Among a total number of 79 cases of proven NCA infections, C. parapsilosis (36.8%) was the most prevalent species followed by C. glabrata (32.9%), C. orthopsilosis (11.4%), C. tropicalis (8.9%), C. krusei (5.0%) and C. guilliermondii (5.0%). The susceptibility to FCZ was assessed for C. parapsilosis (96.5%), C. orthopsilosis (88.9%), C. tropicalis (85.7%) and C. guilliermondii (50.0%). C. glabrata and C. krusei isolates were not susceptible to FCZ. NCA species were distributed in various phylogenetic clades including C. glabrata (1), C. tropicalis (3), C. parapsilosis (6) and C. orthopsilosis, C. krusei and C. guilliermondii (each 2).

Conclusion: C. parapsilosis and C. glabrata were the most predominant NCA species involve in the etiology of candidiasis. C. orthopsilosis was reported from superficial candidiasis. Taken together, our results further substantiate the increasing importance of the involvement of NCA species in the etiology of candidiasis.

Keywords: Antifungal susceptibility; Broth microdilution; Candidiasis; Fluconazole; ITS sequencing; Non-Candida albicans species.