副猪嗜血杆菌血清型和外膜蛋白P5基因型多样性的研究

副猪嗜血杆菌(Haemophilus parasuis,Hps)的血清型及基因型具有复杂多样性。本研究用间接血凝试验对某一猪场分离的Hps进行血清分型鉴定,并对部分菌株的外膜蛋白P5基因进行克隆测序和进化发育分析。试验结果显示,在21头病死猪不同部位共分离了42株Hps,其中 Hps血清5型17株(40.7%)、血清14型12株(28.5%)、血清4型1株(2.3%)和未定型12株(28.5%)。本试验中有5头猪同时感染2种不同血清型的Hps。21株Hps临床分离株分属5个不同基因序列型(STA～STE),其中STA有12株(12/21)为优势基因型;相同血清型的Hps分离株具有不同的STs型,来自同一头猪的Hps血清型和STs型也不相同。以上结果表明,同一猪群感染的Hps血清型和基因型存在明显的多样性,同一头猪感染Hps的血清型和基因型也存在多样性。本研究为进一步揭示猪群感染Hps的复杂性,研究该病的感染与流行机制提供了有价值的参考。

Study on the Diversity of Serovars and OmpP5 Genotypes of Haemophilus parasuis Isolated from the Same Pig Farm

Haemophilus parasuis had complicated diversities of serovars and genotypes. In this study, the H.parasuis isolated from the same farm were investigated the serovars by indirect hemagglutination test, and the outer membrane protein P5 genes were cloned, sequenced and analyzed with the neighbor-joining dendrogram from some strains. The results showed that the 42 H.parasuis strains were isolated and identified from the 21 diseased or died pigs. The serotyping results showed that there were 17 of serovar 5 (17/42, 40.7%), 12 of serovar 14 (12/42,28.5%), 1 of serovar 4 (1/42,2.3%) and non-typable (12/42,28.5%). Interestingly, we found that two different serovars simultaneously isolated in the same pig. Based on the difference of ompP5 gene sequences, the five different sequence types (STs, A to E) were identified from 21 isolates, in which STA was the predominant type in isolates. Furthermore, we also found that the isolates of the same serovar had different ompP5 STs, and even the isolates from the same pig also had different serovars and ompP5 STs. The above results exhibited that the serovar and genotype of H.parasuis isolated from the same pig farm possessed the obvious diversity, and serovars and genotypes infected the same pig also existed the diversities. Hence, this study further revealed the infectious complication of H.parasuis in pig farm, and provided valuable information for the study of infection and epidemiology in H.parasuis.