Antibiotic Resistance in Wastewater Treatment Plants in Croatia: Focus on Extended-Spectrum ß-Lactamases and Carbapenemases
Integrated antibiotic resistance surveillance is one of the objectives of the World Health Organization global action plan on antibiotic resistance (AR), one of the biggest threats to global health today. Wastewater treatment plants (WWTPs) are among the most important reservoirs of AR in urban environments. With a holistic, interdisciplinary approach, the WasteCare is designed to assess the role of WWTPs in spreading of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) which are of highest concern in clinical settings. We will apply quantitative PCR (qPCR) to assess the prevalence of extended-spectrum ß-lactamase (ESBL) and carbapenemase genes as well as selected pathogens as relevant carriers of these genes in wastewaters from geographically dispersed WWTPs in Croatia over two seasons. As a complement to qPCR, the prevalence of ESBL- and carbapenemase-producing E. coli and other coliforms will be assessed by culturing. This will enable us to assess local AR trends in WWTPs and their ability to remove target ARGs and pathogens. The generated survey will lay the groundwork for epicPCR analyses to identify bacterial hosts of carbapenemase gene(s) in WWTPs. This, in combination with the isolation and characterization of enterobacterial isolates by phenotypic and molecular methods, will be crucial in understanding which species may be of major relevance for the spread of target AR via wastewaters. Finally, direct capturing of ESBL- and carbapenemase-producing plasmids from wastewater bacteria to E. coli as a recipient and their complete sequencing will be critical in drawing conclusions about the potential for exchange of AR of special clinical concern between environmental and clinical settings. We believe that this knowledge will have vital implications for the development of effective policy and wastewater management strategies to reduce the risk of hazardous ARB and ARGs being disseminated into the environment and thence back to humans.