Soku Yesutor K, Reeves Jaelyn, Kadzviti Faith W, Samuel Temesgen, Mohamed Abdelrahman
Department of Pathobiology, College of Veterinary Medicine, Tuskegee University, Tuskegee, AL, 36088, USA.
BMC Microbiol. 2025 Aug 4;25(1):478. doi: 10.1186/s12866-025-04222-x.
Aquaculture systems may contribute to the emergence and persistence of antimicrobial-resistant (AMR) bacteria, posing risks to animal, environmental, and human health. This study characterized the phenotypic and genotypic antimicrobial resistance profiles of Enterococcus spp. isolated from the skin microbiota of 125 channel catfish (Ictalurus punctatus) harvested from two earthen ponds in Alabama, USA.
Skin swabs from the body of channel catfish were enriched in Enterococcosel broth and cultured on Enterococcosel agar at 28 °C for 24 h. Isolates were confirmed using Biolog Gen III and VITEK2, and antimicrobial susceptibility was determined using the Kirby-Bauer disk diffusion method. Thirty-five randomly sampled isolates underwent whole-genome sequencing for genotypic characterization.
36% of isolates exhibited multidrug resistance (resistance to ≥ 3 antimicrobial classes), with the highest resistance rates observed for ampicillin (44.8%), rifampicin (42.4%), and tetracycline (38.4%). The most prevalent resistance genes were aac(6')-Iid (65.7%), aac(6')-Ii (22.9%), efmA, and msr(C) (20.0% each). Plasmid replicons rep1 and repUS15 frequently co-occurred with resistance genes. Biofilm-associated genes, including efaA, fsrA, fsrB, sprE, ebpABC, ace, and scm, were commonly detected. Multivariate analyses (PERMANOVA, PCA) revealed no significant species-level differences in resistance burden or biofilm gene carriage, indicating similar resistance and virulence gene carriage across species in this dataset.
The skin microbiota of pond-raised catfish harbors antimicrobial-resistant Enterococcus spp. with mobile resistance elements and biofilm-associated virulence factors, suggesting a potential role in AMR persistence within aquaculture settings. These findings support the need for targeted AMR surveillance in fish-associated microbiota as part of integrated One Health strategies.
水产养殖系统可能促使抗菌药物耐药（AMR）细菌的出现和持续存在，对动物、环境和人类健康构成风险。本研究对从美国阿拉巴马州两个土池中捕捞的125条斑点叉尾鮰（Ictalurus punctatus）皮肤微生物群中分离出的肠球菌属的表型和基因型抗菌药物耐药谱进行了表征。
从斑点叉尾鮰鱼体采集皮肤拭子，在肠球菌肉汤中富集，并在28℃的肠球菌琼脂上培养24小时。使用Biolog Gen III和VITEK2对分离株进行鉴定，并使用 Kirby-Bauer 纸片扩散法测定抗菌药物敏感性。对35个随机抽样的分离株进行全基因组测序以进行基因型表征。
36%的分离株表现出多重耐药性（对≥3类抗菌药物耐药），氨苄西林（44.8%）、利福平（42.4%）和四环素（38.4%）的耐药率最高。最常见的耐药基因是aac(6')-Iid（65.7%）、aac(6')-Ii（22.9%）、efmA和msr(C)（各20.0%）。质粒复制子rep1和repUS15经常与耐药基因同时出现。经常检测到与生物膜相关的基因，包括efaA、fsrA、fsrB、sprE、ebpABC、ace和scm。多变量分析（PERMANOVA、PCA）显示，在耐药负担或生物膜基因携带方面没有显著的物种水平差异，表明该数据集中不同物种的耐药和毒力基因携带情况相似。
池塘养殖鲶鱼的皮肤微生物群中含有具有移动耐药元件和生物膜相关毒力因子的抗菌药物耐药肠球菌属，这表明其在水产养殖环境中AMR持续存在方面可能发挥作用。这些发现支持在鱼类相关微生物群中进行有针对性的AMR监测，作为一体化“同一健康”战略的一部分。
