不同地区鸡源产气荚膜梭菌的毒素型鉴定和药敏试验

Regionalvariations of toxinotypes and drug- resistance profiles in Clostridium perfringens strains isolated from broiler chickens in China

为探明我国鸡群中产气荚膜梭菌(Clostridium perfringens,Cp)不同毒素型分布特征及携带主要致病毒素基因和对饲用抗菌素的抗药谱,于2013年7月至2014年5月间从四川等7省17个肉鸡生产较为集中的地区采样692份,分离鉴定获得Cp菌株214株,分离率31%。经多重PCR方法鉴定,其中有206株为A型Cp,8株为C型。利用特异性单一PCR方法检测发现:有87株Cp携带β2毒素基因,阳性率为41%;5株携带Net B毒素基因,阳性率为2.3%。以最小抑菌浓度法(MIC)检测的常见饲用抗菌素敏感性结果显示:那西肽、弗吉尼亚霉素和效霉素有广泛的抑菌作用,四川德阳(2013)、四川眉山(2013)和广东鹤山(2013)的分离菌株对所测试的11种药物均表现敏感,而广西桂林(2014)的菌株仅对那西肽敏感。结果表明我国鸡源Cp具有明显的毒素型、主要致病毒素基因携带状况和抗药谱的地区差异。

To ascertain the regional variations of toxinotypes,the carrying rates of β2 / NetB toxin（ principle pathogenic toxins） gene,and the resistance profiles against the antibiotics mainly used in Clostridium perfringens（ Cp） strains from broiler chickens in China,692 specimens were collected from faces and intestinal mucosa / contents of broilers reared in 17 geographic districts of 7 provinces. Based on the results of selective culturing,biochemical tests and 16 S r DNA sequence,214 stains（ 31%） of Cp were identified from the samples,of which206 and 8 strains were differently classified into toxinotype A and C by multiplex PCR identification using major toxin（ α,β,ε,and ι） gene- specific primers. Furthermore,87 strains carrying β2 toxin gene and 5 strains with NetB toxin gene were also identified using single PCR with specific primers,accounting for 41% and 2. 3% in all the isolated strains,respectively,and all the net B- positive strains carried β2toxin gene. Minimum inhibitory concentration（ MIC） test results showed that the antibiotics used only for a short time in China such as nosiheptide,virginiamycin,and avilamycin had widely good antibacterial effects to the isolates,and all the tested strains from Deyang and Meishan of Sichun province（ 2013）,and Heshan of Guangdong province（ 2013） were sensitive to all the detected 11 drugs,but the strains from Guilin of Guangxi province（ 2014） was only unresisting to nosiheptide. The results here has primarily revealed that the features of regional variations in toxinotype,main toxin gene carrying,and drug- resistance among the Cp isolates from chickens in China.