Detection of pathogenic bacteria in hot tap water using the qPCR method: preliminary research

Abstract

Drinking water should be safe for health and free from amounts of pathogenic microorganisms and parasites posing a threat to human health. In recent years, particular attention has been paid to the threat associated with the operation of hot water installations, potentially providing favourable conditions for the development of bacteria of genera Legionella and Escherichia. Such bacteria are commonly found in the natural environment, but should not reach the consumers’ taps. In this experiment, hot water samples were collected from six public buildings, and the detection of pathogenic microorganisms, namely Legionella spp., Legionella pneumophila, and Escherichia coli bacteria, was performed by means of qPCR analysis. The sequences specific for these bacteria were quantified with TaqMan probes in total DNA extracts of the hot tap water samples. Bacteria of the Legionella spp. type were detected at five sampling sites in the range from 4.52 to 15.59 genomes/mL of hot tap water. Legionella pneumophila was detected at four sampling sites in the range from 0.98 to 11.99 genomes/mL. E. coli was recorded at four sites, but in quantities around 0.00 genomes/mL (less than one genome/mL). This preliminary research points to the need to use molecular techniques as an additional source of information in standard water analyses to obtain shorter detection time and more accurate results.