禽致病性大肠杆菌脂多糖核心型分布与毒力基因的相关性分析

【目的】大肠杆菌脂多糖(LPS)核心型根据其化学结构的不同分为5种，即R1、R2、R3、R4和K12。通过对禽致病性大肠杆菌(Avian pathogenic Escherichia coli，APEC)安徽、江苏、上海和河南等省市分离株的脂多糖核心型分布情况的研究，分析其与大肠杆菌主要毒力基因之间的潜在联系，以期为APEC的研究和防治提供参考。【方法】对分离到的76株APEC，利用PCR方法开展对LPS核心型分型鉴定和毒力基因检测；分析LPS核心型的分布和毒力基因、致病性之间的相关性。【结果】在76株APEC分离株中，68.4% (52株)为R1核心型，15.8% (12株)为R3型，11.8% (9株)为R4型，3.9% (3株)为R2型，未检测到K12核心型。毒力基因鉴定结果中yijp、mat、fimC、ibeB和ompA的检验阳性率均达到90%以上，可作为APEC的保守基因。其中LPS核心型R1与neuC、cva/cvi、irp2均具有显著正相关性(P<0.05)，R3与iroN、irp2均具有显著负相关性(P<0.05)，R4核心型与aatA显著正相关(P<0.05)。【结论】APEC的LPS核心型主要为R1。LPS核心型对部分毒力基因分布具有显著影响。

Distribution of lipopolysaccharide core type in avian pathogenic Escherichia coli and its correlation with virulence gene

[Objective] The core type of Escherichia coli lipopolysaccharide (LPS) is divided into 5 types, R1, R2, R3, R4 and K12, based on their different chemical structure. The aim of the present study was to study the distribution of LPS core type in avian pathogenic E. coli, and its correlation with virulence genes. [Methods] LPS core type and 17 virulence genes were detected in 76 strains of APEC by PCR. The correlation of LPS core type and virulence was analyzed. [Results] The core types of R1, R3, R4 and R2 were 68.4%, 15.8%, 11.8 and 3.9%, respectively. The virulence genes yijp, mat, fimC, ibeB and ompA were conserved in APEC strains. The R1 core type was significantly positive correlated with neuC, cva/cvi and irp2 (P<0.05), the R4 core type was positive correlated with aatA, whereas the R3 core type was negative correlated with iroN and irp2 (P<0.05). [Conclusion] R1 core type is more prevalent than other LPS core types and associated with high pathogenicity.