东南沿海地区水禽源大肠杆菌耐药表型及耐药基因型的调查

为研究水禽中大肠杆菌的耐药表型及耐药基因型,本研究从中国广东、福建、浙江、江苏和山东5个省市的水禽养殖场及周边环境中采集鸭粪便样品、水样以及土样1 505份,采用选择性培养基和基质辅助激光解吸电离飞行时间(MALDI-TOF-MS)质谱分离鉴定大肠杆菌,采用微量肉汤稀释法检测耐药表型,采用PCR方法筛选大肠杆菌中的25种耐药基因。结果显示,1 505份样品中共分离鉴定出449株大肠杆菌,分离率为29.8%,其中335份来源于粪便,52份来源于土壤,62份来源于水,这些样品中浙江(43.3%)和广东(43.2%)的分离率最高,其次是福建(28.1%)和江苏(23.8%),山东(18.3%)的分离率最低。449株大肠杆菌具有多重耐药性,对氨苄西林、环丙沙星、金霉素、氟苯尼考和磺胺类药物的耐药率分别为90.2%、50.3%、96.7%、87.3%和90.6%,而对替加环素和美罗培南则比较敏感,来源不同省份的大肠杆菌对不同抗菌药呈现出不同的耐药率。PCR检测结果发现,449株大肠杆菌中耐药基因tet(A)检出率最高(88.2%),随后是floR(58.13%)、sul2(57.02%)、tet(B)(53.9%)、cmlA(39.2%)和sul1(36.75%),未检测到qnrA、tet(M)和tet(X)耐药基因的大肠杆菌。在这5个省份中,上述耐药基因在山东省样品中分布均较高,而在浙江省和江苏省样品中分布较低。综上所述,本研究调查了中国东南沿海五省水禽及环境中大肠杆菌的耐药现状,为养殖业抗生素的规范使用提供理论依据。

Investigation on Drug Resistant Phenotype and Genotype of Escherichia coli from Waterfowl in Southeast Coastal China

In order to study the drug resistant phenotype and genotype of Escherichia coli (E. coli) in waterfowl, a total of 1 505 duck feces, water and soil samples were collected from waterfowl farms and their surrounding environment in Guangdong, Fujian, Zhejiang, Jiangsu and Shandong provinces of China. E. coli were isolated by selective medium and identified by MALDI-TOF-MS mass spectrometry.Drug resistance phenotypes were detected by minimal broth dilution method, and the 25 drug resistant genes in E.coli were screened by PCR.The results showed that a total of 449 strains of E.coli were isolated and identified from 1 505 samples, the separation rate was 29.8% and 335 were from feces, 52 were from soil and 62 were from water, among these samples, Zhejiang (43.3%) and Guangdong (43.2%) were the highest, followed by Fujian (28.1%) and Jiangsu (23.8%), and Shandong (18.3%) had the lowest separation rate.449 strains of E.coli were multiple drug resistance.The resistance rates to ampicillin, ciprofloxacin, aureomycin, florfenicol and sulfonamides were 90.2%, 50.3%, 96.7%, 87.3% and 90.6%, respectively, while they were sensitive to tegacyclin and meropenem.E.coli from different provinces showed different resistance rates to different antibiotics.The PCR results showed that in 449 strains of E.coli, the detection rate of resistance gene tet(A) was the highest (88.2%).It was followed by floR (58.13%), sul2 (57.02%), tet(B)(53.9%), cmlA (39.2%) and sul1 (36.75%), the positive E.coli of qnrA, tet(M) and tet(X) were not detected.Among the 5 provinces, the distribution of all drug resistance genes was high in the samples of Shandong province, but low in the samples of Zhejiang and Jiangsu provinces.In conclusion, this study investigated the drug resistance status of E.coli in waterfowl and surrounding environment of 5 coastal provinces in Southeast China, providing a theoretical basis for the standard use of antibiotics in aquaculture.