Improved viability assay to accurately detect microbial pathogens in water: development for Salmonella and Campylobacter

摘要

Humans can be exposed to enteric pathogens through various routes of transmission including water. Improved detection methods for pathogenic microorganisms are required to accurately establish the occurrence and risk of infection from different sources, as current methods often underestimate or overestimate the viable cell number. This research focussed on Salmonella and Campylobacter as two important enteric pathogens of concern in drinking water. In this study, a quantitative PCR method was combined with a sample pre-treatment step using propidium monoazide (PMA) to specifically detect viable cells. Improvements were made to the sensitivity of the method, and so that the method could be used for a number of different applications. The new modified PMA-PCR method was able to discriminate live and dead cells of both Salmonella and Campylobacter over a large range of bacterial concentrations. The method was also effectively applied to compare the survival of Campylobacter strains in river water, and results showed that there was some difference in survival patterns between the strains tested.