南文金，黄健强，吴静波，胡鸿惠，彭国良，肖正中

（1. 韶关学院动物疫病实验室，广东 韶关 512005；2. 粤北生猪生产及疫病防控协同创新发展中心，广东 韶关 512005）

粤北地区仔猪腹泻源大肠杆菌毒力基因检测及致病性初步研究

南文金1，2，黄健强1，2，吴静波1，2，胡鸿惠1，2，彭国良2，肖正中2

（1. 韶关学院动物疫病实验室，广东 韶关 512005；2. 粤北生猪生产及疫病防控协同创新发展中心，广东 韶关 512005）

采用PCR方法对56株仔猪黄白痢源大肠杆菌肠毒素和耶尔森菌强毒力岛（HPI）相关毒力因子STa、STb、LT和irp2进行检测，进而根据毒力因子基因型对部分菌株进行致病性试验。结果显示，38株受试菌检测到毒力因子，其中STa基因阳性率为3.57%，STb基因阳性率为53.57%，LT基因阳性率为7.14%，irp2基因阳性率为21.43%，检测的毒力因子表现为5种基因型，主要的毒力因子基因型是STb和STb+irp2。致病性试验显示毒力基因阳性菌株均对小白鼠具有致病性。结果表明，粤北地区致仔猪黄白痢大肠杆菌流行的主要毒力因子为STb，其次为irp2、少数菌株携带STa和LT毒力因子，相关毒力基因检测可以作为快速确定大肠杆菌致病性的重要依据。

大肠杆菌；肠毒素；强毒力岛；毒力基因；致病性

Abstract：Enterotoxin virulence-related gene （STa，STb and LT） and HPI gene （irp2） of 56 strains of Escherichia coli isolated from piglets with diarrhea were detected by corresponding PCR，and part of strains were chosen according to virulence factors gene-type for animal pathogenicity test. The results showed that 38 strains had virulence genes，the positive rates of STa，STb，LT and irp2 genes respectively were 3.57%，53.57%，7.14% and 21.43%. There were 5 virulence factors genotypes，the major genotypes were STb and STb+irp2.The pathogenicity test showed that positive strains had pathogenicity to mice. In north Guangdong，the major virulence factors of pathogenic E. coli from diarrhea piglets were STa and irp2，a few strains carried STa and LT，some isolates expressed two virulence factors. Detection of virulence genes was an important reference for rapid determining pathogenicity of E. coli.

Key words：Escherichia coli；enterotoxin；high pathogenicity island；virulence genes；pathogenicity

大肠杆菌是一种重要人兽共患病原菌，原发或继发感染致病性大肠杆菌引起的仔猪腹泻（黄白痢）是养猪生产中常见的一种细菌性疾病［1］。大肠杆菌是一种条件性致病菌，常由阴冷潮湿、昼夜温差大、转群换料等环境和应激因素导致仔猪发病和死亡。大肠杆菌引起的仔猪腹泻因发病日龄不同表现出不同的临床症状和特点，仔猪黄痢主要发生在7日龄内新生仔猪，仔猪白痢主要发生在1周龄到断奶哺乳仔猪［2］。……