我国5省区部分猪、鸡源产ESBLs沙门菌的耐药差异及MLST流行特征

Drug resistance difference and MLST epidemic characteristics of Salmonella ESBLs from pigs and chickens in five provinces of China

为了解不同地区猪鸡源沙门菌的流行分布和耐药特征,采用PCR法、药敏纸片法、微量肉汤稀释法及Bionumerics和SPSS软件等,对来自我国安徽、浙江、山东、新疆、江苏5省区的沙门菌进行血清型鉴定、ESBLs表型和基因型检测、药物敏感性试验以及数据处理。结果显示,85株沙门菌共鉴定出15种血清型;分离出25株(29.4%)产ESBLs菌株,猪源产超广谱β内酰胺酶(extended-spectrumβ-lactam,ESBLs)沙门菌检出率(4.7%)远低于鸡源(54.8%)(P<0.01);产ESBLs沙门菌对7种抗菌药的耐药率显著高于非产ESBLs的菌株(P<0.01);85株沙门菌中基因型检测结果为:TEM型44.7%(38/85),CTX-M型12.9%(11/85),OXA型10.6%(9/85),SHV型9.4%(8/85),有基因型共存现象;产ESBLs沙门菌中有19株携带4种耐药基因,相关性达到76%;各省分离菌株对氨苄西林、庆大霉素、大观霉素、头孢噻呋、四环素、头孢他啶的耐药率有极显著差异(P<0.01),对恩诺沙星的耐药率有显著差异(P<0.05),江苏分离菌株耐药率最低,新疆分离菌株耐药率最高;85株沙门菌共分为19个ST型,猪源沙门菌的优势序列型为ST34、ST155、ST469,鸡源为ST11、ST34、ST198。结果显示:产ESBLs沙门菌在鸡场广泛存在,其表型和基因型检测结果有高相关性,对多种抗菌药普遍耐药;鸡源沙门菌较猪源耐药严重;不同省区耐药率也有较大差异,江苏菌株耐药率为5省中最低;5省区血清型、ST型差异较大,不同ST型菌株有较为固定的血清型。提示应根据不同动物源、地区的具体情况指导实际生产,因地制宜,对症下药,预防和减少耐药性的产生。

To understand the epidemic distribution and drug resistance characteristics of Salmonella from pigs and chickens in different regions,PCR method,drug-sensitive paper method,broth microdilution method,Bionumerics and SPSS software were used to analyze Salmonella from Anhui,Zhejiang,Shandong,Xinjiang and Jiangsu Provinces.Serotype identification,ESBLs phenotype and genotype detection,drug sensitivity tests,and data processing were performed.The results showed that a total of 15 serotypes were identified from 85 strains of Salmonella.Twenty-five strains(29.4%)were isolated,and the detection rate of Salmonella ESBLs-producing bacteria in pigs(4.7%)was much lower than that from chickens(54.8%,P<0.01).The resistance rate of ESBLs-producing Salmonella to 7 kinds of antibiotics was significantly higher than that of non-ESBLs-producing Salmonella(P<0.01).The genotypes of 85 Salmonella strains were as follows:TEM 44.7%(38/85),CTX-M 12.9%(11/85),OXA 10.6%(9/85),SHV 9.4%(8/85).Nineteen strains of ESBLsproducing Salwonella carried four kinds of drug resistance genes,and the correlation reached 76%.The resistance rates of isolates from different provinces were significantly different to ampicillin,gentamicin,ceftiofuran and tetracycline and ceftazidime(P<0.01),and significantly different to ofloxacin(P<0.05).The resistance rate of isolates from Jiangsu was the lowest,and the resistance rate of isolates from Xinjiang was the highest.The 85 strains of Salmonella were divided into 19ST types.The dominant sequence types of Salmonella from pig were ST34,ST155 and ST469,and the dominant sequence types of Salmonella from chicken were ST11,ST34 and ST198.In conclusion,Salmonella ESBLs-producing bacteria existed widely in chicken farms,and its phenotype and genotype test results have high correlation,and it was generally resistant to a variety of antimicrobial drugs.Salmonella from chicken was more resistant than that from pig.The drug resistance rate of Jiangsu was the lowest among the five provinces.The differences of serotype and ST type between the five provinces and regions were significant,and different ST strains had relatively fixed serotype.It is suggested that the actual production should be guided according to the specific conditions of different animal sources and regions,and the medicine should be tailored to the specific conditions to prevent and reduce the generation of drug resistance.