Abstract
A correlation between resident non-pathogenic bacterial populations in certain natural mineral waters and their beneficial effects has been established by several research groups. This study aims to characterize the bacterial composition of the Rivanazzano salso-bromo-jodic and sulphurous mineral waters (Pavia, Italy). Water samples were collected from natural sources and dispensing systems. DNA was extracted and subjected to 16S rRNA gene sequencing. Microbial composition, as well as alpha and beta diversity, were analyzed using amplicon sequence variants and compared across sampling sites. The predominant phyla in both waters were Proteobacteria, Campylobacterota, Bacteroidota, and Desulfobacterota. However, diversity at the family taxonomic level was recorded. In terms of bacterial diversity, waters collected from the dispensing systems within the spa resort were more similar between them than those from natural sources. The therapeutic properties of the Rivanazzano mineral waters are likely to be related to their combined mineral and biological composition.