Abstract:
ABSTRACT
PCR is a molecular technique which is used to detect small amount of microorganisms from a sample very rapidly and with specificity by amplifying the DNA strand of the targeted microbe. Traditional methods have low detection sensitivity and these detect microbes that are present in concentration of more than 102-103 cfu/ml in a sample. Escherichia coli and Salmonella typhimurium are pathogenic microorganisms that may cause severe gastrointestinal illness in humans, but as with most waterborne pathogens these are difficult to detect and enumerate with accuracy in drinking waters due to methodological limitations. The aim of the current study was to develop a PCR protocol for the detection of Salmonella conserved gene invA and 0157 gene of E. coli 0157:H7 and E. coli virulence gene SLT-I (Shiga like toxin) in drinking water. For determining the efficiency of the current protocol for water analysis, six already identified drinking water contaminated sites within Rawalpindi and Islamabad were chosen. Results showed the presence of invA gene of Salmonella in all samples which indicates its conserved nature in Salmonella and also its prevalence in the water distribution network. Whereas some site showed the presence of 0157 and SLT-I genes of E.coli while the biochemical tests of all these sites shows presence of E.coli, which revealed that E.coli is present but the strains of Ecoli having these genes are not dominating the micro flora of this region.
This protocol is viable for drinking water analysis and can detect the specific genes of species within the mix consortium of microbes at the fraction of time (24 hours compared to 6 days).
