Monitoring Antibiotic Resistance in Wastewater: Findings from Three Treatment Plants in Sicily, Italy.

Antimicrobial resistance (AMR) poses a global public health threat. Wastewater analysis provides valuable insights into antimicrobial resistance genes (ARGs), identifying sources and trends and evaluating AMR control measures. Between February 2022 and March 2023, pre-treatment urban wastewater samples were collected weekly from treatment plants in Pantano D'Arci, Siracusa, and Giarre (Sicily, Italy). Monthly composite DNA extracts were prepared by combining weekly subsamples from each site, yielding 42 composite samples-14 from each treatment plant. Real-time PCR analysis targeted specific ARGs, including blaSHV, erm(A), erm(B), blaOXA, blaNDM, blaVIM, blaTEM, and blaCTX-M. The preliminary findings revealed that blaERM-B, blaOXA, blaTEM, and blaCTX-M were present in all samples, with erm(B) (median value: 8.51; range: 1.67-30.93), blaSHV (0.78; 0.00-6.36), and blaTEM (0.72; 0.34-4.30) showing the highest relative abundance. These results underscore the importance of integrating ARG data with broader research to understand the persistence and proliferation mechanisms of ARGs in wastewater environments. Future studies should employ metagenomic analyses to profile resistomes in urban, hospital, agricultural, and farm wastewater. Comparing these profiles will help identify contamination pathways and inform the development of targeted ARG surveillance programs. Monitoring shifts in ARG abundance could signal cross-sectoral contamination, enabling more effective AMR control strategies.