Assessment of natural water quality using most potable number (mpn)

Most potable number (MPN) method was used to reckon microorganisms per 100 mL in water samples collected from hot springs, ground water sources, domestic water sources and urban area. This method provided sufficient and accurate results to prove the presence of contamination in potable and recreational waters. Of the total 90 samples, six samples showed highest number of total coliform. Selected six samples found MPN total coliform greater than permissible value have detected the presence of E. coli ranging from 2 to 140 MPN per 100 mL. Total 15 isolates were isolated from these samples. Of 15 isolates, selected three isolates showed colourless to bright pink coloured colonies, highly motile small rods, positive for glucose, inositol, lactose, maltose, mannitol, salicin, sucrose, TSI test and negative for sorbitol. LATEX REAGENT TEST shows identified Escherichia coli isolate has serogroup O157:H7 antigen. Three biochemically identified Escherichia coli confirmed using16S rRNA gene sequence analysis. Obtained results indicate the presence of pathogenic microorganism in water samples. Hence, attributor to strict sanitation, high level of hygienic sanitary conditions, strict preventive practices should be adopted to reduce possibilities of infection.