Predictors of carbapenemase-producing bacteria occurrence in polluted coastal waters

The spread of carbapenemase-producing bacteria is a worldwide concern as it challenges healthcare, especially considering the insufficient development of antimicrobials. These microorganisms have been described not only in hospitals, but also in several environmental settings including recreational waters. Community exposure to antimicrobial-resistant bacteria through recreation might be relevant for human health, but risk assessment studies are lacking. Absence of effective and feasible monitoring in recreational aquatic matrices contributes to such a knowledge gap. Here, we aimed at assessing predictors of occurrence of medically relevant carbapenemase-producing bacteria in coastal waters. We quantitatively assessed recovery of carbapenemase-producing Enterobacteriaceae, Pseudomonas spp., Acinetobacter spp. and Aeromonas spp. in superficial coastal waters showing distinct pollution history across one year, and registered data regarding tide regimen, 7-days pluviosity, salinity, pH, water temperature. We analyzed data using General Estimating Equation (GEE) to assess predictors of such occurrence. Our results suggest that the sampling site had the strongest effect over concentration of these antimicrobial-resistant microorganisms, followed by pollution indexes and tide regimen. Increased salinity, advanced sampling time, water temperature, rainfall and decrease of pH were related to decrease concentrations. We provide a list of factors that could be easily monitored and further included in models aiming at predicting occurrence of carbapenemase producers in coastal waters. Our study may encourage researchers to further improve this list and validate the model proposed, so that monitoring and future public policies can be developed to control the spread of antimicrobial resistance in the environment.