The microbiological content of drinking water traditionally is determined by employing culture-dependent methods that are unable to detect all microorganisms, especially those that are not culturable (Brumfield et al. PLoS One. 2020). This research project intends to verify the presence of "antibiotic resistance bacteria" (ARB) and their related genes (ARGs), and class 1 integrons, in drinking water, utilizing molecular methods. Molecular methods will allow the assessment of ARGs also from non-cultivable species, or in bacterial species not normally researched in water drinking assessment. In fact we should considered that viable but not culturable bacteria (VBNC), or also other cultivable bacteria not normally investigated such as Gallionella ferruginea, Geobacter, Desulfovibrio, Aeromonas etc., could harbor resistance genes. This method of research should therefore allow avoiding that the amount of ARBs in drinking water is underestimated.
We therefore intend to investigate on the possible presence of ARB and their related ARGs in different drinking water and mineral water samples. The samples will be collected at the point of consumer use (tap water) and from bottled mineral water samples.
Using standard filtration methods, the total bacterial DNA collected from different water samples will be assayed for the presence of the related ARGs and intI gene via qPCR techniques.
The proposed research represent the first study in Italy, with a metagenomics approach, aimed at investigates the presence of bacterial ARGs in drinking water, usually not tested for this purpose. Results will indicate whether different drinking waters could be a potential source of antimicrobial resistance genes (ARGs) for human consumers, as well as giving us strategic information about the opportunity to extend this study to a wider scenario of Italian drinking waters, eventually extending this research also to the presence of freely circulating (extracellular) genes, in drinking water.
