Third-Generation Cephalosporin-Resistant Escherichia coli Isolates Belonging to High-Risk Clones Obtained from Fresh Pork Meat in La Plata City, Argentina

High-risk clones represent a major concern, as they are very efficient vehicles for mobile genetic elements carrying antimicrobial resistance genes and therefore promote their spread, especially if they confer resistance to cefotaxime, ciprofloxacin, and fosfomycin, included within the highest-priority, critically important antimicrobial agents (HPCIA). Between February 2022 and April 2024, 138 pork samples were obtained from 46 butcher shops in La Plata, Buenos Aires, Argentina. A total of 102 HPCIA-resistant E. coli were isolated. Eighty-five HPCIA-resistant E. coli were selected for whole-genome sequencing. Of these, 27 belonged to 9 clones described as high risk: ST101 (n = 5), ST10 (n = 4), ST48 (n = 4), ST744 (n = 4), ST23 (n = 3), ST58 (n = 2), ST88 (n = 2), ST117 (n = 2), and ST410 (n = 1). Twelve of them were third-generation cephalosporin-resistant. Resistance was mediated by blaCTX-M-55 (n = 7), blaCTX-M-14 (n = 4), blaCTX-M-8 (n = 1), and blaCMY-2 (n = 1). This study highlights the importance of food products and the food production chain as reservoirs of high-risk clones and resistance genes of epidemiological relevance to public health.