Distribution of Candida species in different clinical samples and their virulence: biofilm formation, proteinase and phospholipase production: a study on hospitalized patients in southern India.

Introduction: Candida species are normal inhabitants of the skin and mucosa. The importance of epidemiological monitoring of yeasts involved in pathogenic processes is unquestionable due to the increase of these infections over the last decade;

Materials And Methods: The clinical samples from the respiratory tract (sputum, bronchial wash, tracheal secretions), saliva, blood, urine, middle ear discharge, vitreous fluid, corneal ulcer, and plastic devices (endotracheal tube, catheter tip, suction tip) were collected and cultured. The species of Candida isolated were identified.

Results: A total of 111 isolates of Candida species were recovered from 250 diverse clinical sources. C. albicans (39.64%) was the most isolated species, although the Candida non albicans species with 60.36% showed the major prevalence. In blood cultures, C. krusei (38.23%) and C. albicans (20.58%) were isolated frequently. C. albicans (63.27%) was the predominant species in mucosal surface. Urinary tract infections caused by yeasts were more frequent in hospitalized patients, C. krusei (50.0%) being commonly isolated, followed by C. albicans (25.0%).

Discussion: Several virulence factors like, biofilm, proteinase, phospholipase, etc. contribute to the pathogenecity. Early detection of virulence factors by Candida is useful in clinical decision making. We therefore have aimed at demonstrating the formation of biofilm using the method proposed by Branchini et al, (1994). The proteinase produced by Candida was estimated as per the method of Staib et al, (1965). Phospholipase assay was carried out as per the method of Samaranayake et al, (2005).

Conclusions: The data suggests that the capacity of Candida species to produce biofilm may be a reflection of the pathogenic potential of the isolates. C. krusei and C. tropicalis showed strong slime production. The non-Candida albicans produced more proteinase than C. albicans. C. albicans produced higher levels of phospholipase than non Candida albicans in this study.