483株肉鸡源大肠埃希菌和肺炎克雷伯菌中ISCR1及int1基因的流行及耐药情况

Dissemination of insertion sequence common regions 1 and intl gene and drug resistance of 483 Escherichia coli and Klebsiella pneumonia broiler isolates

目的 研究山东肉鸡源细菌中ISCR1和int1基因的流行及耐药情况。方法 于2014年6月，在山东某大型肉鸡养殖场中选择日龄在37 d的待宰肉鸡作为采样对象。将鸡舍分为东部、南部、西部、北部、中部5区，选取不同区域肉鸡，采用单纯随机方法，按照1∶50比例进行泄殖腔拭子采样，共得到肉鸡粪便样本400份，经分离共得到483株非重复性样本菌株，其中大肠埃希菌373株（77.2%），肺炎克雷伯菌110株（22.8%）；采用微量肉汤稀释法，测定菌株对8类10种抗菌药物的最低抑菌浓度；并对int1和ISCR1基因进行PCR扩增和测序；比较携带两种基因的大肠埃希菌、肺炎克雷伯菌的耐药程度差异。结果 483株菌株中，共检测到携带int1基因的菌株为440株（91.1%），携带ISCR1基因的菌株为126株（26.1%），同时携带int1和ISCR1基因的菌株共有126株（26.1%）。37株同时不携带ISCR1和int1基因的大肠埃希菌耐受0~2、3~5、6~8类药物的比例分别为13.5%（5株）、78.4%（29株）和8.1%（3株），288株仅携带int1基因的大肠埃希菌耐受0~2、3~5、6~8类药物的比例分别为2.4%（7株）、74.7%（215株）和22.9%（6株），两者差异有统计学意义（P〈0.001）；26株仅携带int1基因的肺炎克雷伯菌耐受0~2、3~5、6~8类药物的比例分别为11.5%（3株）、76.9%（20株）和11.5%（3株），78株同时携带ISCR1和int1基因的肺炎克雷伯菌耐受0~2、3~5、6~8类药物的比例分别为0、35.9%（28株）和64.1%（50株），两者差异有统计学意义（P〈0.001）。结论 int1和ISCR1基因在大肠埃希菌和肺炎克雷伯菌中的检出率较高，两类基因同时存在可介导更高程度的耐多药表型。

Objective To investigate and analyze distribution characteristics of two multidrug resistance related genes in broiler isolates in Shandong province.Methods The pre slaughter broilers were chosen from Shandong province in this study in June, 2014. A total of 400 fecal samples from five different zones （east, south, west, north and middle） of the hen house were collected. 373（77.2%） Escherichia coli and 110 （22.8%） Klebsiella pneumonia strains were isolated, and ISCR1 and int1 gene were detected by PCR assay and sequencing. The resistance to 10 drugs belonging to 8 classes antimicrobial drugs were obtained by using minimal broth dilution method and data analysis. The difference between isolates and drug resistance profiles was analyzed.Results Among 483 isolates, 440 isolates （91.1%）, 126 isolates （26.1%） and 126 isolates （26.1%） were detected as int1, ISCR1 and both two gene carriers, respectively. The rate of 37 E. coli isolates not carried ISCR1 or int1 gene resistant to 0 to 2, 3 to 5, 6 to 8 classes antimicrobial agents was 13.5% （n=5）, 78.4% （n=29）, and 8.1% （n=3）, respectively; the rate of 288 only int1 gene E. coli carriers resistant to 0 to 2, 3 to 5, 6 to 8 groups antimicrobial agents was 2.4% （n=7）, 74.7% （n=215）, and 22.9% （n=6）, respectively. The data above showed significant difference （P〈0.001）. The rate of 26 only int1 gene K. pneumonia carriers resistant to 0 to 2, 3 to 5, 6 to 8 classes antimicrobial agents was 11.5% （n=3）, 76.9% （n=20）, and 11.5% （n=3）, respectively; the rate of 78 both two gene K. pneumonia carriers resistant to0 to 2, 3 to 5, 6 to 8 groups antimicrobial agents was 0, 35.9% （n=28）, and 64.1% （n=50）, respectively. The data above showed significant difference （P〈0.001）.Conclusion Gene int1 and ISCR1 showed high prevalence in E. coli and K. pneumonia isolates. High level multi-drug resistance profile could be mediated by int1 and ISCR1 gene co-existence.