DETECTION OF MICROBIAL PATHOGENS IN DRINKING WATER BIOFILM USING PCR

Abstract

Bacterial contamination in drinking water biofilm provides a potential source for bacteria to grow and increase rapidly. To understand the microbial density in drinking water distribution system (DWDS), a four month study was carried out. The aim of this study was to examine biofilm in three different pipe materials including Polyvinyl Chloride (PVC), Polypropylene (PPR) and Galvanized Iron (GI) in an educational institution. A set of all these pipe materials was installed in DWDS at eight different locations and analyzed after every fifteen days. Among different parameters measured, dissolved oxygen, organic carbon and residual chlorine were found to be the main indicators of microbial presence. Microbial identification made by molecular methods of pathogenic detection (PCR based gene sequencing) detected Bacillus cereus strain SH42, Lactobacillus crispatus ST1, Lactobacillus jensenii 269-3, Staphylococcus aureus A9719, Paenibacillus sp. P22, Staphylococcus haemolyticus strain KJ1-5-97, Pseudomonas sp. Lc31-4, Bacillus sp. BAB-3357, Paenibacillus sp. P22, Achromobacter sp. BQNT2, Taylorella asinigenitalis and Tetrathiobacter kashmirensis strain 3T5F as prominent species and their accession number were obtained from NCBI (National Center for Biotechnology Information). Significant increase in bacterial population was observed in GI pipes biofilm while least in PPR pipes. The quantity of DWDS bacteria was directly depended on biofilm growth and its increase was correlated with presence of organic matter on pipes. Pipe material also affected the biofilm thickness while similarity in bacterial species was observed between system due to same disinfectant dose, time period and plumbing pipes.