β-lactams resistance gene quantification in an antibiotic resistant Escherichia coli water suspension treated by advanced oxidation with UV/H2O2

Water is one of the most important habitats and route for the spread of antibiotic resistance (AR) in the environment and disinfection processes can be a potential barrier to minimise this risk. In this study the effect of UV/H2O2 process on the potential of AR transfer was investigated through cultivation methods vs (polymerase chain reaction) PCR based methods. bla TEM was selected as target antibiotic resistance gene (ARG) and was quantified by qPCR in the survived colonies and the whole suspension (total DNA). The detection limit of residual antibiotic resistant Escherichia coli (E. coli) colonies (5CFUmL-1) was reached after 240min treatment, but bla TEM gene was still present in total DNA after 300min (2.8×106 copies mL-1), and no effect was observed in DNA extracted from cell cultures (3.8×108 copies mL-1 after 90min). Accordingly, the investigated disinfection process may select for unaffected ARGs, therefore contributing to the potential transfer of AR in the environment.