Distribution of Candida albicans and non-albicans Candida in clinical samples and their intrinsic biofilm production status

Abstract

Background: Candida species, mainly Candida albicans are traditionally associated with severe and debilitating diseases especially in immunocompromised hosts. Biofilm is emerging virulence factor in fungi and has been correlated with pathogenicity among Candida species. The emergence of C. albicans and non-albicans Candida (NAC) species producing biofilms and severe or recurrent infections in hospitalized patients with its attendant treatment failure and poor prognosis has become a great concern globally. Objective: To determine the species distribution of Candida organisms (C. albicans and NAC) from clinical samples and their pathogenic ability to produce biofilms; and to highlight the clinical implications of these extracellular substances to aid preventive measures, chemotherapy, and prognosis. Materials and Methods: This was a descriptive, cross-sectional study, and was carried out at SRM MCH & SR, Tamil Nadu, India. Between February 2014 and January 2015, a total of 90 Candida fungal isolates recovered from clinical samples including urine, pus, vaginal swab, skin scrapping, sputum, and blood were analyzed. Samples were cultured on Sabouraud Dextrose Agar with gentamycin. Candida organisms were identified by standard methods. Germ tube rapid test was used to differentiate C. albicans and Candida dublinieses from other Candida species. Further speciation of the isolates was carried out by culture on CHROM agar and Corn meal-Tween 80 agar, including sugar fermentation and assimilation tests. Biofilm production was detected using Congo red method. Results were analyzed statistically. Result: A total of 90 Candida organisms were recovered from clinical specimens of which 33 (36.7%) were C. albicans and 57(63.3%) were NAC species. Majority of the isolates were recovered from urine (42, 46.7%), vaginal swab (20, 22.2%), and pus (11, 12.2%) samples. Among NAC species, the most common isolate was C. tropicalis (23, 25.6%) followed by C. parapsilosis (15, 16.7%). Of the 90 Candida species analyzed, 26 (28.9%) gave positive results for biofilm production. Overall, biofilm formation was detected more frequently among NAC species (16, 61.5%) than in C. albicans (10, 38.5%). Among NAC species, C. tropicalis (12, 46.2%) produced biofilm most frequently than other members of the group. Although, most of the Candida isolates strongly producing biofilms were members of NAC species particularly C. tropicalis (3, 50%), nonetheless, majority of the weakly biofilm producers were also detected among the strains of C. tropicalis (9, 45%). Conclusion: The outcome of this study shows a notable shift in the pathogenic incidence of Candida species from C. albicans to NAC species with significant rate of pathogenic biofilm production. Biofilm production was most common in C. tropicalis than other members of NAC species whereas slime formation was not detected in C. glabrata species. There is need to create awareness among the populace and stakeholders on healthcare system management about this emerging scenario in Candida species pathogenicity, biofilm production, and clinical repercussions for appropriate measures to checkmate the trend.