Characterization of Enterobacterales resistant to extended-spectrum cephalosporins isolated from meat in Tunisia.

Food-producing animals are potential reservoirs of resistances to antibiotics classified as critically important for human health, such as extended-spectrum cephalosporins (ESC) and carbapenems (CP). Even though human-to-human contacts are the primary vector of antimicrobial resistance (AMR) dissemination in the community, food consumption and preparation plays a non-negligible role in the global burden. In order to document the levels of meat contamination in Tunisia, 71 samples of meat products (chicken, n=25; sheep, n=30; bovine, n=7; goat, n=6; camel, n=3) collected in 2024 in the Sousse region were studied using selective media, antibiograms, as well as short- and long-read sequencing. No CP-resistant isolate was identified, but 46 (64.8%) of the samples carried ESC-R Enterobacterales, with chicken meat being the most contaminated meat (80%). The collected isolates were identified as E. coli (68.0%), K. pneumoniae (26.0%) and Enterobacter hormaechei (6.0%), most of which carried bla-type genes. Despite a high genetic diversity, clonal spread was suspected in several cases, notably due to clones (ST540, ST155, ST117) presenting a zoonotic and/or One Health importance. Plasmids also played a role in the spread of resistance. We observed the decline of the IncI1/ST3 but the presence of the IncF/F-:A-:B53 and IncY, which are both emerging as important carriers of the bla gene worldwide. This study revealed the need of surveillance and the effective implementation of the national action plan in the veterinary sector to decrease the AMR burden in the food-producing sector.