Antibiotic Resistance Genes (ARGs) are contaminants of emerging concern with marked potential to impact public and environmental health. This review focusses on factors that influence the presence, abundance, and dissemination of ARGs within Wastewater Treatment Plants (WWTPs) and associated effluents. Antibiotic-Resistant Bacteria (ARB) and ARGs have been detected in the influent and the effluent of WWTPs worldwide. Different levels of wastewater treatment (primary, secondary, and tertiary) show different degrees of removal efficiency of ARGs, with further differences being observed when ARGs are captured as intracellular or extracellular forms. Furthermore, routinely used molecular methodologies such as quantitative polymerase chain reaction or whole genome sequencing may also vary in resistome identification and in quantifying ARG removal efficiencies from WWTP effluents. Additionally, we provide an overview of the One Health risk assessment framework, as well as future strategies on how WWTPs can be assessed for environmental and public health impact.

Dissemination of antibiotic resistance (AR) in marine environments is a global concern with a propensity to affect public health and many ecosystems worldwide. We evaluated the use of sea turtles as sentinel species for monitoring AR in marine environments. In this field, antibiotic-resistant bacteria have been commonly identified by using standard culture and sensitivity tests, leading to an overrepresentation of specific, culturable bacterial classes in the available literature. AR was detected against all major antibiotic classes, but the highest cumulative global frequency of resistance in all represented geographical sites was against the beta-lactam class by a two-fold difference compared to all other antibiotics. Wastewater facilities and turtle rehabilitation centres were associated with higher incidences of multidrug-resistant bacteria (MDRB) accounting for an average of 58% and 49% of resistant isolates, respectively. Furthermore, a relatively similar prevalence of MDRB was seen in all studied locations. These data suggest that anthropogenically driven selection pressures for the development of AR in sea turtles and marine environments are relatively similar worldwide. There is a need, however, to establish direct demonstrable associations between AR in sea turtles in their respective marine environments with wastewater facilities and other anthropogenic activities worldwide.