Key Findings

The study identifies blaCTX-M-14 and blaTEM-153 as extended-spectrum beta-lactamases in commensal Enterobacteriaceae in Portugal, along with sul1, sul2, and sul3 as sulfonamide resistance genes. These genes are part of mobile genetic elements such as integrons and plasmids, highlighting the role of commensal flora as a reservoir of clinically relevant antibiotic resistance genes.