小样本量下浙江省猪鸡源肠球菌对停、限用抗菌药物最小抑菌浓度分布变迁的追踪分析

为追踪了解浙江省猪鸡源肠球菌对停、限用抗菌药物耐药性变化趋势，利用微量肉汤稀释法对2019年至2023年间浙江省40家猪鸡养殖场的肠球菌耐药性进行了持续跟踪监测。在小样本量条件下，基于MIC分布曲线、MIC50和耐药系数方法，评估了这些肠球菌对吉他霉素、黄霉素、恩拉霉素、那西肽、维吉尼亚霉素、杆菌肽和氧氟沙星等7种停、限用抗菌药的最小抑菌浓度的变化趋势。结果表明，鸡源和猪源肠球菌对杆菌肽的耐受水平下降趋势明显；对吉他霉素、黄霉素和恩拉霉素的耐受水平总体呈下行趋势，其中吉他霉素和黄霉素表现为先升后降，恩拉霉素则表现为先降后升；对那西肽、维吉尼亚霉素均相对较为敏感，但低浓度MIC值的菌株略有增多；对氧氟沙星呈现出物种差异，鸡源肠球菌相对较为敏感，且耐受水平有进一步下行的趋势，猪源肠球菌对氧氟沙星耐受水平相对较高，且中等浓度MIC值菌株数于2022年出现较大幅度上升。

Tracking analysis on the distribution of minimal inhibitory concentrations of Enterococcus from Pigs and Chickens in Zhejiang Province under small sample quantity

To track and analysis the trends of antibiotic resistance to the restricted and discontinued antibacterial of Enterococcus from pig and chicken in Zhejiang Province, the micro broth dilution method was used to continuously monitor the antibiotic resistance of Enterococcus from 40 pig and chicken farms in Zhejiang Province from 2019 to 2023. Under small sample size conditions, based on the MIC distribution curve, MIC50, and resistance coefficient method, the trend of minimum inhibitory concentration (MIC) of these Enterococcus against seven discontinued and restricted antibiotics, including Guitarimycin, Xanthomycin, Enramycin, Nasilide, Virginiamycin, Bacitracin, and Ofloxacin, was evaluated. The results showed that the tolerance level of Enterococcus to bacteriocins from chicken and pig sources showed a significant downward trend; The tolerance levels to Guitarimycin, Xanthomycin, and Enramycin showed an overall downward trend, with Guitarimycin and Xanthomycin showing an initial increase followed by a decrease, while Enramycin showed an initial decrease followed by an increase; The strain is relatively sensitive to both naseptide and virginiamycin, but there is a slight increase in strains with low concentration MIC values; There are species differences in the tolerance to ofloxacin, and chicken derived Enterococcus is relatively sensitive, with a further downward trend in tolerance levels. Pig derived Enterococcus has a relatively high tolerance level to ofloxacin, and the number of medium concentration MIC value bacterial strains has significantly increased in 2022.