不同系统进化群鸡源大肠杆菌耐药性调查分析

Antibiotical Resistance Investigation and Analysis of Chicken Originated E.coli Strains of Different Phylogenetic Groups

[目的]通过系统进化群和耐药性分析,了解鸡源大肠杆菌致病菌株的分布情况及耐药特征,为有效控制鸡大肠杆菌病提供依据。[方法]采用微量肉汤稀释法测定菌株耐药表型(MIC),采用PCR法检测耐药基因和系统进化群分群试验,采用SPSS17.0软件进行差异显著性分析。[结果]低致病群B1(38.1%)和非致病群A(34.0%)菌株分布相对较多,其次是高致病群D(21.2%)和B2(6.2%);分离菌株对氨苄西林(87.2%)、四环素(87.0%)、复方新诺明(87.0%)和磺胺异噁唑(80.0%)耐药严重,多重耐药率高达98.86%,但对多粘菌素E敏感;耐药基因sul1(71.0%)、sul2(44.8%)、sul3(18.7%)、tet A(42.2%)、tet B(15.8%)、tet M(7.3%)均有检出,tet C、tet O、tet K、tet L、tet W均未检出,9.13%菌株同时携带3种sul基因,仅有一株菌同时携带3种tet基因。表型耐药菌株携带耐药基因的能力明显高于非耐药菌株(P<0.05)。高致病群B2、D群耐药程度较B1和A群严重,对氧氟沙星、庆大霉素、大观霉素、头孢噻呋、磺胺异噁唑、复方新诺明、奥格门丁等7种药物差异显著(P<0.05)。[结论]我国鸡源大肠杆菌高致病菌株检出率高,且耐药程度相对严重,在适宜条件下更易导致鸡群发病且难以控制。

[Objective]The aim of the study is to know the distribution and drug-resistance of pathogenic poultry-originated E.coli strains through phylogenetic group and drug resistance analysis,and provide references for prevention and control of chicken colibacillosis.[Method]The antimicrobial susceptibility（MIC） was detected by mini broth dilution susceptibility test,the resistance gene and phylogenetic groups were detected by PCR and the significance of difference was analyzed by SPSS17.0 software. [Result]The low pathogenic group B1（38.13%） and the nonpathogenic group A（34.02%）were more distributed than the highly pathogenic group D（21.23%） and B2（6.16%）. The resistance of 438 E.coli isolates to ampicillin（87.2%）,tetracycline（87.0%）,sulfamethoxazole/trimethoprim（87.0%） and sulfisoxazole（80.0%） was serious,multiple resistance rate was up to 98.86%,but the isolates were sensitive to colistin E. The resistance gene sul1（71.0%）,sul2（44.8%）,sul3（18.7%）,tet A（42.2%）,tet B（15.8%） and tet M（7.3%） existed in E.coli isolates,but tet C,tet O,tet K,tet L and tet W were not found. 9.13% isolates carried 3 sul genes,and only 1 isolate carried 3 tet genes. The ability of resistant isolates to carry resistance genes was significantly higher than the non-resistant ones（P〈0.05）. The resistance of the strains from highly pathogenic group B2 and D was higher than the strains from group B1 and A,and there was significant difference to the seven drugs such as ofloxacin,gentamicin,spectinomycin,ceftiofur,sulfisoxazole,sulfamethoxazole/trimethoprim,amoxicillin/clavulanic acid（P〈0.05）.[Conclusion]The ratio of highly pathogenic strains of chicken-originated E.coli in China was high,and the drug-resistance was relatively serious,likely result in poultry diseases under the suitable conditions and difficulty to control.