患子宫内膜炎母猪产道致病菌谱分析及卟啉单胞菌的分离鉴定

【背景】子宫内膜炎是规模化养殖场母猪常患的生殖道疾病之一，对养殖业造成的经济损失较大，细菌感染是常见的病因之一，但具体病原及致病机制尚未完全明确。【目的】探究产道菌群对母猪子宫内膜炎的影响。【方法】采用第三代细菌16S rRNA基因全长高通量测序技术进行对比，研究健康和患有子宫内膜炎母猪产道菌群差异，并依据菌群分析结果对子宫内膜炎母猪产道分泌物进行细菌分离。建立荧光定量PCR计数方法测定母猪产道样品中的卟啉单胞菌数。【结果】健康和患子宫内膜炎母猪产道菌群的丰富度和多样性差异显著；与健康组母猪相比，患子宫内膜炎母猪产道菌群变形菌门(Proteobacteria)、拟杆菌门相对丰度显著增加(P<0.05)。在属分类水平上，健康母猪产道的主要优势菌属为金黄杆菌属、芽孢杆菌属、毛螺菌属等，这些优势属在患子宫内膜炎母猪产道丰度降低，患子宫内膜炎母猪产道丰度最高的菌属为埃希氏菌属(Escherichia)、Rodentibacter和卟啉单胞菌属(Porphyromonas)。在种水平上，Porphyromonas somerae是患子宫内膜炎母猪产道的主要条件性致病菌。依据菌群分析结果，本研究从子宫内膜炎母猪产道分泌物中分离到一株卟啉单胞菌，经鉴定该菌16S rRNA基因与Porphyromonas somerae DSM 23386 strain JCM 13867(NR_113090.1)相似性达99.04%。荧光定量PCR计数方法测定，子宫内膜炎母猪产道卟啉单胞菌数量显著高于健康母猪(P<0.05)，推测卟啉单胞菌与该批次母猪子宫内膜炎病因有关。【结论】本研究为子宫内膜炎母猪的病因和发病机制奠定基础，并为其治疗提供理论依据。

Microbiota in the birth canal of sows with endometritis and isolation and identification of Porphyromonas

Background] Endometritis, one of the common reproductive tract diseases of sows in large-scale breeding farms, causes severe economic losses to the breeding industry. Bacterial infection is one of the common causes of endometritis, while the specific pathogens and pathogenesis remain to be studied. Objective] To explore the microbiota in birth canal on sow endometritis.Methods] The third-generation bacterial 16S rRNA gene high-throughput sequencing was employed to compare the microbiota in the birth canal of sows with endometritis and healthy sows. According to the sequencing results, bacteria were isolated from the vaginal secretions of the sows with endometritis. Furthermore, quantitative real-time PCR (qPCR) was conducted to determine the number of Porphyromonas in the birth canal. Results] The richness and diversity of the microbiota in the birth canal showed significant differences between health sows and those suffering from endometritis. Compared with the healthy sows, those suffering from endometritis had increased relative abundance of Proteobacteria and Bacteroidetes (P<0.05). The dominant genera in the birth canal of healthy sows were Chryseobacterium, Bacillus, and Lachnospira, which showed declined abundance in the sows with endometritis. Escherichia, Rodentibacter, and Porphyromonas were the dominant genera in the birth canal of the sows suffering from endometritis. Porphyromonas somerae is a major bacterial species in the birth canal of sows with endometritis. According to the results of microbiota analysis, a strain of Porphyromonas was isolated from the vaginal secretion of sows with endometritis, which shared the 16S rRNA gene homology of 99.04% with P.somerae DSM 23386 strain JCM 13867 (NR_113090.1). In addition, the number of Porphyromonas in the birth canal of the diseased sows was higher than that in the healthy sows (P<0.05). Conclusion] Porphyromonas may be related to the endometritis in this batch of sows. This study lays a foundation for deciphering the etiology and pathogenesis of sow endometritis as well as a theoretical basis for treating endometritis in sows.