Biofilm production by clinically isolated Candida : Comparative analysis based on specimen, methodology, and various Candida species

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Aim and objectives The importance of Candida as a human pathogen has increased, particularly in the hospitalized and immune compromised patients . Candida albicans , the predominant species worldwide, is now being replaced by the more resistant non- albicans Candida. This study compares various biofilm producing clinical isolates of Candida species by three commonly available methods for biofilm detection. Material and methods Clinical samples from patients with suspected fungal/ Candida infections were cultured. Candida isolates were speciated on the basis of colony morphology, germ tube formation, chlamydospore formation on corn meal agar and color production on HiCrome Candida agar and confirmed using Vitek-2 Yeast-ID cards. Biofilm production was performed visually by modification of the tube method, spectrophotometrically by Percent transmittance method and Crystal violet assay. Results 20.6% of Candida isolates were obtained. Candida albicans (33.3%) was outnumbered by the non- albicans species (66.7%). Crystal violet micotitre plate assay demonstrated highest positivity (54.8%), followed by percent transmittance microtitre plate method. C. glabrata was the highest biofilm producer, followed by C. tropicalis. Conclusion Biofilm production is very common among Candida isolates, more so for the non- albicans Candida species. Routine testing for biofilm production should be contemplated particularly in serious patients with Candida infection, not responding to typical anti-fungal therapy.