Constitutive presence of antibiotic resistance genes within the bacterial community of a large subalpine lake

The fate of antibiotic resistance genes (ARGs) in environmental microbial communities is of primary concern as prodromal of a potential transfer to pathogenic bacteria. Although of diverse origin, the persistence of ARGs in aquatic environments is highly influenced by anthropic activities, allowing potential control actions in well-studied environments. However, knowledge of abundance and space–time distribution of ARGs in ecosystems is still scarce. Using quantitative real-time PCR, we investigated the presence and the abundance of twelve ARGs (against tetracyclines, β-lactams, aminoglycosides, quinolones and sulphonamides) at different sampling sites, depths and seasons, in Lake Maggiore, a large subalpine lake, and in the area of its watershed. We then evaluated the correlation between each ARG and a number of ecological parameters in the water column in the deepest part of the lake. Our results suggest the constitutive presence of at least four ARGs within the bacterial community wi...