Opportunistic fungi in lake water and fungal infections in associated human population in Dal Lake, Kashmir

Natural habitats of opportunistic fungal pathogens are outside of the host; therefore, it is critically important to understand their ecology and routes of transmission. In this study, we investigated the presence of human pathogenic opportunistic fungi in lake water and incidence of fungal infections in associated population in Kashmir, India. Six hundred forty water samples were taken on seasonal basis from a wide network of sampling stations of the lake for an extended period of two years for screening their occurrence. The samples were inoculated onto rose bengal agar, malt extract agar, potato dextrose agar and other specified culture media supplemented with Chloramphenicol and Streptomycin followed by incubation at 37 degrees C. All the samples were positive for fungi, which were later identified by sequencing the rDNA internal transcribed spacer region aided by classical morphological culture techniques and physiological profiling. The whole process led to the isolation of sixteen species of opportunistic fungal pathogens belonging to genus Aspergillus, Candida, Penicillium, Cryptococcus, Fusarium, Rhizopus and Mucor in decreasing order of prevalence. Furthermore, 20% population (n = 384) of Dal inhabitants was examined for possible fungal infections and it was observed that only 8.07% individuals were positive for fungal infections with 4.68% skin infection cases, 2.34% onychomycosis cases and 1.04% candidiasis cases. Scrapings from onychomycosis and candidiasis patients showed the presence of Aversicolor and Calbicans respectively, resembling exactly the strains isolated from the lake water. However, the skin infection was because of a dermatophyte not isolated for the lake water. Higher prevalence of infection (6.77%) was seen in people using lake water followed by a positive prevalence of 1.30% using tap water. The results of present study suggest that the lake inhabitants are at a greater risk of getting life threatening fungal diseases which may lead to various morbidities. (C) 2016 Elsevier Ltd. All rights reserved.