Inhibitory Effects of Antifungal Drugs on Biofilm Producing Aspergillus spp. Recovered from Drinking Water System

Abstract

Aims: Biofilms formed in drinking water distribution systems serve as a continuous source of fungal infections. Biofilms are thick aggregates of adherent microorganisms including pathogenic species of fungi. Respiratory diseases and skin allergy reactions are caused by drinking water containing biofilm forming fungus and bacteria. One of the main causes of nosocomial infections and respiratory diseases in hospitals is due to the fungal biofilm formation in machines, catheters and other surgical instruments. There are some antifungal drugs which are used to control biofilm formation to minimize the infection rate. Methodology and results: The present study was conducted to isolate and identify Aspergillus species which are the main fungal spp. responsible for the biofilm formation in drinking water and to check their antifungal susceptibility against antifungal drugs. The isolated fungal samples from drinking water were cultivated on Potato dextrose agar for the isolation of Aspergillus species. Isolated Aspergillus species were identified on the basis of cultural, morphological and microscopic examination. Then in-vitro ability of biofilm produced by isolated Aspergillus species was estimated using microtitre plate method and quantification by crystal violet assay. Antifungal susceptibility testing against isolated fungal spp. was done by antifungal drug Amphotericin B. Results: From results, it is concluded that drinking water of labs, hospitals and common water chillers were more prevelant by Aspergillus species whereas water from reverse osmosis plants showed negative results. From microtitre plate method and crystal violet assay, it was concluded that Aspergillus spp. are Susceptible against Amphotericin B drug as compared to miconazole. Keywords: Aspergillus spp; Biofilm; Drinking water; Disk diffusion method; Amphotericin B