Occurrence of Enterobacterales producing extended-spectrum β-lactamases in organic and conventional food collected in France

The spread of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) is a major public health concern, best addressed through a One Health approach that considers the interconnectedness of human, animal, and environmental reservoirs, including food. As agricultural practices evolve, organic farming has gained importance, but its role in reducing ESBL-PE contamination in food remains unclear. This study aimed to compare ESBL-PE contamination in food products from organic and conventional farming systems. The results may offer perspectives for evaluating sources of human contamination by ESBL-PE. Between November 2020 and February 2022, 448 food samples - 223 meat and 225 raw vegetables - were collected in the Bourgogne Franche-Comté region (Eastern France). Among them, 230 were from organic and 218 from conventional production. ESBL-PE were isolated using selective culture, identified by MALDI-TOF mass spectrometry, and characterized by MultiLocus Sequence Typing. Antibiotic susceptibility was tested using agar diffusion, and ESBL genes were identified by PCR and sequencing. Overall, ESBL-PE contamination was rare (4.2 %) and observed exclusively in meat products, with no detection in vegetables. Contamination rates did not differ significantly between organic and conventional products (p-value = 0.485). Poultry meat showed the highest contamination levels (17.8 %, p-value = 0.002). The 22 ESBL-PE isolates recovered from 19 samples included Escherichia coli (n = 18), Klebsiella pneumoniae (n = 3), and Enterobacter hormaechei (n = 1). The most common ESBL genes were bla_CTX-M-15 (n = 6) and bla_SHV-12 (n = 4). In conclusion, ESBL-PE contamination levels were similar in organic and conventionally produced food products. Although some isolates harbored bla_CTX-M-15, a gene prevalent in human infections, our findings suggest that food is not a major source of human ESBL-PE exposure, although its role cannot be ruled out.