Zhao Jianfei, Liu Rui, Sun Yanpeng, Yang Xiaojun, Yao Junhu
College of Animal Science and Technology, Northwest Agriculture & Forestry University, Yangling, 712100, China.
Anim Nutr. 2022 Feb 5;9:223-232. doi: 10.1016/j.aninu.2022.01.005. eCollection 2022 Jun.
The prevalence and transmission of vancomycin-resistant (VRE) in enterococci being as probiotics has been neglected in the scientific literature. The application of enterococci in feed, food and health products may cause VRE transmission through the food chain. This study evaluated phenotypic resistance of species to 20 antibiotics along a pork production chain from feed to food. It also assessed the genetic diversity of isolates. A total of 510 samples (feed, = 70; swine manure, = 400; swine carcasses, = 20, and retail pork, = 20) were collected in Beijing, China. A total of 328 enterococci isolates with 275 and 53 were identified using 16 S rRNA. Antimicrobial susceptibility to all enterococci isolates was conducted using the K-B method for 20 antibiotics from 9 categories. Multilocus sequence typing (MLST) was conducted on the isolates to survey the dissemination of enterococci in the pig industry. The results showed that only 26 enterococci isolates were sensitive to the 20 antibiotics, while half of the isolates (164/328) had acquired multi-drug resistance. The resistant rate to furazolidone was 68.60%, followed by 42.99% to tetracycline. One vancomycin-resistant isolates were isolated from feed origin and 2 from manure origin, with minimum inhibitory concentrations to vancomycin of 1,024, 64, and 64 μg/mL, respectively. The MLST outcomes showed that the 275 isolates belonged to 11 sequence types (ST) including ST40, ST60, ST94, ST160, ST178, ST296, ST361, ST695, ST726, ST812 and ST1014. The ST of the feed-sourced VRE was ST1014, while the 2 manure-sourced VRE was ST69. ST1014 evolved from ST78, which was the dominant clonal complex in most cities of China, leading to the spreading of VRE. These findings revealed the potential safety hazards of commercial probiotic enterococci in China and showed that there is a risk of the VRE horizontally transferring from feed to food.
肠球菌作为益生菌时耐万古霉素肠球菌（VRE）的流行情况及传播在科学文献中一直被忽视。肠球菌在饲料、食品和保健品中的应用可能会导致VRE通过食物链传播。本研究评估了猪肉生产链（从饲料到食品）中肠球菌对20种抗生素的表型耐药性。还评估了分离株的遗传多样性。在中国北京共采集了510份样本（饲料，n = 70；猪粪，n = 400；猪胴体，n = 20；零售猪肉，n = 20）。使用16S rRNA鉴定出328株肠球菌分离株，其中275株为粪肠球菌，53株为屎肠球菌。采用K-B法对所有肠球菌分离株进行9类20种抗生素的药敏试验。对分离株进行多位点序列分型（MLST）以调查肠球菌在养猪业中的传播情况。结果显示，仅26株肠球菌分离株对20种抗生素敏感，而一半的分离株（164/328）获得了多重耐药性。对呋喃唑酮的耐药率为68.60%，其次对四环素的耐药率为42.99%。从饲料来源分离出1株耐万古霉素肠球菌分离株，从粪便来源分离出2株，对万古霉素的最低抑菌浓度分别为1024、64和64μg/mL。MLST结果显示，275株粪肠球菌分离株属于11种序列类型（ST），包括ST40、ST60、ST94、ST160、ST178、ST296、ST361、ST695、ST726、ST812和ST1014。饲料来源的VRE的ST为ST1014，而2株粪便来源的VRE的ST为ST69。ST1014由ST78进化而来，ST78是中国大多数城市的优势克隆复合体，导致了VRE的传播。这些发现揭示了中国商业益生菌肠球菌的潜在安全隐患，并表明存在VRE从饲料水平转移到食品的风险。
