https://doi.org/10.4081/ijfs.2025.14375
C30 | Assessment of carbapenem resistance in commensal Escherichia coli isolated from rabbit carcasses and caecal contents
L. Prandini1, L. Fiorentini2, C. R. Siclari2, M. Parigi3, F. Giacometti4, G. Polizzi1, E. Zanato1, A. Seguino1, V. Indio1, A. De Cesare1, A. Serraino1, F. Savini1. | 1Università di Bologna, Dip. di Scienze Mediche Veterinarie; 2Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia-Romagna, Sede Territoriale di Forlì; 3Azienda USL della Romagna, Dip. Sanità Pubblica, distretto Forlì, U. O. Igiene Alimenti di origine animale; 4Università di Padova, Dip. di Medicina Animale, Produzioni e Salute.
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Accepted: 15 March 2026
Published: 9 September 2025
Purpose. Carbapenems are last-line antimicrobials in the treatment of serious bacterial infections in humans. Although their use is not authorised in food-producing animals in the European Union, there has been an increase in carbapenem-resistant bacteria among microorganisms isolated from animals and food. With Implementing Decision (EU) 2020/1729, antimicrobial resistance monitoring has become mandatory for several microorganisms, including commensal Escherichia coli, in major livestock populations and related meat products. In addition, a recent EFSA report recommends implementing monitoring activities also on food sources not currently included in the official programmes in force. In line with this request, in this preliminary study, meropenem resistance was assessed in E. coli strains isolated from rabbit carcasses and caecal contents. Methods Over 10 slaughter days, 10 samples were taken, each consisting of 5 rabbit carcasses (sampled after evisceration, according to BS EN ISO 17604:2015) and 5 caecal contents from animals other than those used for the carcass samples. The samples collected were seeded on VRBGA medium (BS EN ISO 21528-2:2017). After 24 hours of incubation, 5 colonies were randomly selected based on their different morphology and subjected to identification with MALDI-TOF. Only strains identified as E. coli were subjected to antimicrobial susceptibility testing using the Kirby-Bauer method. Specifically, the susceptibility/resistance profile was evaluated on MacConkey agar, using 10 μg meropenem discs. Results Overall, 224 strains of E. coli were isolated, 80 strains from carcasses and 144 from caecal contents. Based on the clinical breakpoints proposed by EUCAST and CLSI for Enterobacterales, no strain was found to be resistant to meropenem. Similarly, considering the EUCAST epidemiological breakpoints (ECOFF) for E. coli, which allow wild-type microorganisms to be distinguished from non-wild-type microorganisms (i.e., those with phenotypically detectable acquired resistance mechanisms), no isolate showed inhibition values below the threshold diameter of 27 mm, suggesting the exclusive presence of wild-type profiles. Conclusions In conclusion, no E. coli strains isolated from rabbit carcasses and caecal contents showed resistance to carbapenems. This study represents a first contribution to assessing the presence of carbapenem-resistant E. coli in the rabbit sector, which is currently excluded from programmes monitoring the spread of strains resistant to this group of antibiotics.
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