Identification and Characterization of Potential Biocide-Resistant Fungal Strains from Infested Leathers A Systematic Study

Abstract

This study is aimed at identification of biocide tolerant/resistant fungal strains afflicting the leather industry. Fungal infestation occurs sometimes despite biocide treatment during leather processing. This persistent growth can be due to the development of biocide resistance which can lead to health hazards and economic loss. As no study has so far been reported to either confirm this or to identify such fungal strains, a systematic approach has been made in this study to address these aspects. Fungal strains were collected from infested leathers from tanneries to identify biocide resistant fungal strains afflicting leather industry. Phenotypic characterization revealed Aspergillus as the most dominant with 58% occurrence. Ten isolates were subjected to 18s rRNA sequencing and four strains were identified as Aspergillus niger. An in-vitro susceptibility to four leather fungicides was assessed to identify the biocide tolerant strains. S-6 A. niger strain was found to be the most tolerant as evidenced by high MIC (7.81µg ml^-1) against the most effective biocide, 2-(thiocyanomethylthio) benzothiazole. In-vivo studies on chrome-tanned leathers also confirmed this finding. SEM studies revealed considerable morphological changes in S-6 compared to wild strain providing further evidence that it may have developed biocide resistance.