The study identified various multidrug-resistant Enterobacteriaceae (MDR-Ent) in Chicago waterways, including genes encoding beta-lactamases (CTX-M-1, CTX-M-9, SHV-ESBL, CMY-II-AmpC), aminoglycoside modifying enzymes (aac-6'-Ib), quinolone resistance proteins (qnrB), efflux pump components (oqxA/B), and colistin resistance (mcr-1). These genes were found in E. coli, K. pneumoniae, and E. cloacae isolates and conferred resistance to multiple antibiotics.