浙江省猪衣原体(Chlamydia suis)的高度流行性和遗传多样性

High prevalence and genetic diversity of Chlamydia suis in Zhejiang Province

衣原体（Chlamydiaceae）是一类专性细胞内寄生的革兰阴性菌,可引起人和动物的多种疾病。为了解不同样品类型或不同日龄猪中衣原体的流行情况和多样性,随机采集浙江省绍兴市和宁波市两猪场猪的全血样品、结膜拭子、鼻拭子和粪便拭子样品共700份,采用基于23S r RNA基因的FRET-q PCR方法和高分辨率溶解曲线分析进行11种衣原体的检测和分型。结果：猪衣原体是猪的衣原体感染的唯一衣原体种,其阳性率高达63.6%（445/700）。乳猪、保育猪和育肥猪的衣原体阳性率显著高于母猪。血液中猪衣原体的阳性率和拷贝数显著低于其他拭子样品。针对浙江的衣原体阳性样品的基于omp A VD1-2基因片段的系统发育分析,获得了分布于4个亚型的19个变异株,表明该病原体的高度遗传多样性。本研究证实我国猪衣原体存在高度流行性和遗传多样性,为该病原的致病性和传播途径的研究以及防控提供了重要的理论依据。

Chlamydiaceae is Gram-negative obligate intracellular bacterium. They are responsible for a broad range of diseases in animals and humans. To investigate the prevalence and genetic diversity of Chlamydiaceae in pigs of different sample types or different ages,700 samples of whole blood,conjunctival swab,nasal swab and anal swab were collected from pigs in two pig farms in Shaoxing and Ningbo of Zhejiang Province,followed by screening and typing using Chlamydia spp. 23 S r RNA-based FRET-PCR and high-resolution melting curve analysis. The results showed that Chlamydia suis was the only chlamydia species in pigs infected with Chlamydia,with a positivity of 63. 6%（445/700）. The Chlamydia suis positivity in sucking pigs,weaned pigs and finisher pigs had a significantly higher C. suis positivity than in sows. The Chlamydia suis positivity and copy number in blood were significantly lower than in other swabs. Phylogenetic analysis based on the omp A VD1-2 gene fragment of Chlamydia suis-positive samples revealed that 19 mutants distributed in four subtypes were obtained,indicating a significant genetic diversity in the Chlamydia suis strains. This study proved the high prevalence and genetic diversity of C. suis in China,which would provide a significant basis for the pathogenicity,transmission and prevention of this disease.