Screening For Bacteriocin Producers And Biofilm Formers Among Bacterial Isolates Of Water Samples From Hyderabad, Pakistan

Abstract

Polluted and contaminated drinking water supplies upgrading general well-being concerns, particularly in urban areas in developing and low assets nation including Pakistan. Microbiologist are now realizing that in natural, clinical, and industrial settings, bacteria often aggregate in biofilm. Biofilm forms when bacteria adhere to surface in moist environments by excreting a slimy, glue-like substance and become more resistant to antibiotics.  To comprehend the extent of biofilm related water borne general wellbeing risk credited to drinking water, it is fundamental to decide of biofilm formation of those bacteria which have commonly found in drinking water in planktonic form. Therefore, this study aimed to analyze the capacity of biofilm formation of only E. coli detached from drinking water samples collected during the period of this study. Microbial investigation of water was done by using Millipore Filtration technique. The E. coli isolates were recognized by using conventional biochemical tests. The isolates were tested against a range of commercially available antibiotic discs using Disc-diffusion method introduced by Kirby-Bauer. This helped to determine the resistance pattern of the isolates. The capacity of the indigenous pathogens to form biofilm was assessed using tube adherence method and the Congo red method whereas the investigation of the biofilm formation was done on the basis of the adherence of the biofilm to glass test tube and appearance of black colonies with consistency of dry crystalline, respectively. The validity and accuracy of the methodology was checked with use of control strain (E. coli ATCC 25922). Antibiotic susceptibility testing demonstrated high level of resistance among the E. coli isolates against tested antibiotics. The results of this study showed that 79.5% (n=62) of total samples (n=78) were positive for bacterial growth. Furthermore 16.1% (n=10) isolated bacteria were identified as E. coli and remaining were other bacteria. Screening of the water isolates for bacteriocin producers revealed that none of them can produce bacteriocin while result of biofilm detection assay showed that 60 % of E. coli isolates were having potential of biofilm formation. The results might be helpful for policy making regards drinking water supply.