Antimicrobial resistance of Escherichia coli from broilers in large-scale poultry farms in Shandong Province

作者：Xiaoxia Liu, Xiang Li, Jing Liu, Ruiying Chen, Rui Liu, Ruting Zhao, Jia Zhao, Jianwei Hao, Shuming Yang, Aiguo Luo, Ailiang Chen · 发表于：Frontiers in Microbiology · 年份：2025 · DOI：10.3389/fmicb.2025.1685522 · 被引用次数：3 · 研究领域：Animal Nutrition and Physiology、Salmonella and Campylobacter epidemiology、Pharmaceutical and Antibiotic Environmental Impacts

Background Antimicrobial resistance (AMR) is a global challenge affecting both healthcare and agricultural fields, as emphasized by the World Health Organization (WHO). Industrial poultry production plays a crucial role in the development and dissemination of AMR. A comprehensive understanding of the molecular mechanisms underlying AMR is imperative for developing effective control strategies. Materials and methods This study aimed to identify factors influencing AMR in Escherichia coli from large-scale commercial broiler farms. Samples, including 371 anal swabs, 95 fecal swabs, and 122 feed-trough swabs, were collected from Cobb broilers at the four production stages (1, 15, 26, and 38 days of age) on typical farms in Shandong Province. From these specimens, 508 E. coli strains were isolated and characterized. Antimicrobial susceptibility was assessed using the Kirby–Bauer disk diffusion method against 15 commonly used antibiotics, and results were interpreted according to CLSI guidelines. Results The resistance rates of the isolated strains varied between 24.41% and 95.47%. A total of 96.45% of the strains exhibited multidrug resistance, and 29 strains were resistant to all 15 antibiotics. The highest resistance was observed against penicillin (amoxicillin and ampicillin), followed by florfenicol, chloramphenicol, tetracycline, cefotaxime, and cefazolin. The lowest resistance was noted for ofloxacin and gentamicin. Drug resistance was most substantial at 15 days of age comp...