江苏某奶牛场健康奶牛体内产志贺毒素大肠杆菌的分离鉴定及其对小鼠致病性的研究  

Identification of Shiga Toxin-producing Escherichia coli from Healthy Cattle in One Farm of Jiangsu Province and Their Pathogenicity on Mice

作　　者：薛涛[1] 顾丛丛[1] 高崧[1] 焦新安[1] 周琼[1] 张文俊[1] 刘秀梵[1] 

机构地区：[1]扬州大学兽医学院农业部畜禽传染病学重点开放实验室,扬州225009

出　　处：《畜牧兽医学报》2011年第6期830-837,共8页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：国家自然科学基金(3097219630771460);国家"863计划"(2003AA222141);国家支撑计划(2009BADB9B01)

摘　　要：通过对江苏省某奶牛场连续6个月的定群、定畜跟踪调查,获得产志贺毒素大肠杆菌(STEC)在该牛场分布的广泛性、持续性和血清型多样化的资料,并对一些重要血清型分离株作致病性的鉴定。基于本实验室已经建立的多重PCR方法对stx1、stx2、eaeA、ehxA共4个基因进行检测,对检测出的阳性样品,非O157STEC采用多重PCR结合CT-SMAC平板的分离方法,而O157STEC通过免疫磁珠结合O157显色平板的分离方法。结果表明,该奶牛场STEC的初筛率为16.1%(112/696),分离率为11.1%(77/696)。分离株属于35种O血清型和60种O∶H血清型。该场的优势血清型为O4、O26和O93,O157在该场存在,但并非优势血清型。77个分离株中,stx2基因的检出率为68.8%,远远高于其它毒力基因,如stx1(19.5%)、eaeA(11.7%)和ehxA(20.8%)。该场分离到一些O157和O26血清型的菌株,对小鼠具有较强的致病性。奶牛是STEC的天然宿主,可健康带菌。除了O157STEC外,非O157STEC中一些高致病力菌株对人类的健康也存在威胁。Through investigating a herd of cattle from a farm in Jiangsu Province for Shiga toxin-producing Escherichia coli（STEC） over a period of 6 months,we obtained the information of the epidemicity,persistence and diverse serotypes of STEC in this farm and the pathogenicity of some isolates.Polymerase chain reaction（PCR） that had been developed in this laboratory previously was carried out to detect genes of eaeA,stx1,stx2,ehxA.Non-O157 STEC were isolated by using multiplied PCR and CT-SMAC separation,and O157 STEC were isolated by using immunomagnetic combining Chrom-Agar（CA） O157 plates separation from the PCR positive samples.stx genes were detected in 112 of the 696 faecal samples（16.1%）,but only 77 STEC were isolated（11.1%）.These STEC isolates belonged to 35 O serogroups and 60 O∶H serotypes.O4,O26,O93 were the common serotypes.O157 existed in this farm,but not popular.Stx2 positive rate（68.8%） was higher than other genes,e.g.stx1（19.5%）,eaeA（11.7%） and ehxA（20.8%）,among all STEC isolates.Some of the tested isolates were highly pathogenic to mice.The present results showed that the cattle are the natural reservoirs of STEC and they are healthy to carry STEC.In addition to O157 STEC,non-O157 STEC are potential threat to human health.Therefore,to prevent the transmission of STEC from cattle to beef and milk products might be the key route to diminish the infection of STEC in human.

关 键 词：产志贺毒素大肠杆菌 奶牛 多重PCR O抗原 H抗原 毒力基因 

分 类 号：S852.612[农业科学—基础兽医学]