Risk Characterization of Antibiotic Resistance in Bacteria Isolated from Backyard, Organic, and Regular Commercial Eggs

[EN] This study was conducted to assess the risk due to antimicrobial-resistant strains of Salmonella spp., Listeria monocytogenes, and Escherichia coli isolated from the eggshell and the contents of eggs bought in markets in Valencia (Spain). Thirty-four samples from three different production styles were analyzed: standard (n = 34), organic (n = 16), and backyard (n = 10) eggs. L. monocytogenes was not isolated in any style of production. Only one strain of Salmonella was isolated from standard production, which was resistant to ciprofloxacin and amoxicillin. E. coli strains were resistant in 22% of the isolates from organic production, 12.25% from standard production, and 11.23% from backyard production. In all cases, the highest resistance was observed for amoxicillin-clavulanate. None of the isolates from standard and backyard eggs were resistant to chloramphenicol, ciprofloxacin, gentamycin, and streptomycin, while only ceftriaxone was found to be effective against all E. coli isolates from organic eggs. beta-Lactamase genes bla(TEM), bla(SHV), and bla(CMY-2) and the resistance genes for tetracycline tetA, tetB, and tetC were tested. The most commonly detected antimicrobial resistance genes among the E. coli isolates were tetA (49.30%), bla(TEM) (47.89%), and tetB (36.62%). Overall, a maximum public health risk is associated with beta-lactam antibiotics.Fenollar-Penadés, A.; Doménech Antich, EM.; Ferrús Pérez, MA.; Jiménez Belenguer, AI. (2019). Risk Characterization of Antibiotic Resistance in Bacteria Isolated from Backyard, Organic, and Regular Commercial Eggs. Journal of Food Protection. 82(3):422-428. https://doi.org/10.4315/0362-028X.JFP-18-355422428823Clinical and Laboratory Standards Institute (CLSI). 2014. Performance standards for antimicrobial susceptibility testing: twenty-fourth informational supplement. CLSI Document M100-S24. CLSI, Wayne, PA.(2013). The European Union Summary Report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2011. EFSA Journal, 11(5), 3196. doi:10.2903/j.efsa.2013.3196(2016). The European Union summary report on trends and sources of zoonoses, zoonotic agents and food‐borne outbreaks in 2015. EFSA Journal, 14(12). doi:10.2903/j.efsa.2016.4634Evans, J. K., Buchanan, K. L., Griffith, S. C., Klasing, K. C., & Addison, B. (2017). Ecoimmunology and microbial ecology: Contributions to avian behavior, physiology, and life history. Hormones and Behavior, 88, 112-121. doi:10.1016/j.yhbeh.2016.12.003International Organization for Standardization. 2005. Microbiology of the food chain—horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. ISO 11290-1:1997/A1:2005. International Organization for Standardization, Geneva.Lanz, R., Kuhnert, P., & Boerlin, P. (2003). Antimicrobial resistance and resistance gene determinants in clinical Escherichia coli from different animal species in Switzerland. Veterinary Microbiology, 91(1), 73-84. doi:10.1016/s0378-1135(02)00263-8Rivoal, K., Fablet, A., Courtillon, C., Bougeard, S., Chemaly, M., & Protais, J. (2013). Detection of Listeria spp. in liquid egg products and in the egg breaking plants environment and tracking of Listeria monocytogenes by PFGE. International Journal of Food Microbiology, 166(1), 109-116. doi:10.1016/j.ijfoodmicro.2013.06.014Sáenz, Y., Zarazaga, M., Briñas, L., Lantero, M., Ruiz-Larrea, F., & Torres, C. (2001). Antibiotic resistance in Escherichia coli isolates obtained from animals, foods and humans in Spain. International Journal of Antimicrobial Agents, 18(4), 353-358. doi:10.1016/s0924-8579(01)00422-8Scientific Advisory Group on Antimi. (2009). Reflection paper on the use of third and fourth generation cephalosporins in food producing animals in the European Union: development of resistance and impact on human and animal health. Journal of Veterinary Pharmacology and Therapeutics, 32(6), 515-533. doi:10.1111/j.1365-2885.2009.01075.xSHIVAPRASAD, H. L. (2000). Fowl typhoid and pullorum disease. Revue Scientifique et Technique de l’OIE, 19(2), 405-424. doi:10.20506/rst.19.2.1222Utrarachkij, F., Pornraungwong, S., Siripanichgon, K., Nakajima, C., Suzuki, Y., & Suthienkul, O. (2012). Possible horizontal transmission of Salmonella via reusable egg trays in Thailand. International Journal of Food Microbiology, 154(1-2), 73-78. doi:10.1016/j.ijfoodmicro.2011.12.024Voetsch, A. C., Van Gilder, T. J., Angulo, F. J., Farley, M. M., Shallow, S., … Marcus, R. (2004). FoodNet Estimate of the Burden of Illness Caused by NontyphoidalSalmonellaInfections in the United States. Clinical Infectious Diseases, 38(s3), S127-S134. doi:10.1086/38157