Mobility of antibiotic resistance genes in the environment and potential threats for drinking water

Antimicrobial resistance genes are of all ages, however as a result of the consumption of antimicrobial
agents, the occurrence of antimicrobial resistance (genes) increase in clinical environments (hospitals) but
also in the environment (i.e. soil, surface water, and groundwater). The current study describes the
occurrence and fate of resistance genes in a soil environment. Additionally, some implications for
drinking water are shortly discussed. It was found that the amount and diversity of resistance genes
increase in soils as a result of (veterinary) consumption of antimicrobials. Furthermore, resistance genes
are rather hydrophilic and therefore mobile in a soil environment, but their persistence (as free DNA or
in plasmids) is rather short. Nevertheless, these genes remain in soils even years after exposure to
antibiotics or manure application. This suggests that these genes are incorporated in the soil microbial
gene pool. The preliminary interpretation of the literature suggests that risks of antibiotic resistance in
groundwater and produced drinking water is small compared to more obvious risks of infections in
healthcare or via animal products. However, there is hardly any data on the occurrence of resistance
genes in drinking water sources, their recalcitrance in drinking water treatment, let alone potential
human health effects need to be studied in more detail.