1株猪源ST25型猪链球菌血清2型的分离鉴定及生物学特性研究

doi:10.16431/j.cnki.1671-7236.2025.12.041

摘要/Abstract

摘要： 【目的】查明湖北省荆州市某养猪企业猪呼吸道疾病暴发病因，对病原进行生物学特性分析，为猪群疾病防治提供理论依据。【方法】采用PCR法对病料进行猪呼吸道疾病常见病原筛查，如猪链球菌、多杀性巴氏杆菌和猪繁殖与呼吸综合征病毒(PRRSV)等；对患病猪的鼻咽拭子进行细菌分离，通过形态学特征鉴定、16S rRNA基因系统进化分析和多位点序列分析(MLST)对分离菌株进行血清型和分子分型鉴定；通过毒力基因检测、小鼠人工感染试验、生物被膜形成能力测定、耐药基因检测、抗菌药物和中药敏感性试验分析分离菌株的致病性和耐药性。【结果】病原筛查结果显示，患病猪的猪链球菌为阳性，其他病原如多杀性巴氏杆菌、PRRSV等均为阴性；从病猪鼻咽拭子成功分离到1株优势菌，形态学鉴定为革兰阳性链状球菌，16S rRNA基因系统进化分析发现，分离菌株与猪链球菌汇为一支，鉴定其为猪链球菌，命名为JZXW0103；经血清型鉴定和MLST分析确定分离菌株JZXW0103为ST25型猪链球菌血清2型；分离菌株携带毒力基因mrp、sly、orf2、gapdh和sao，具有β-溶血活性，感染小鼠可致肝脏、肺脏和脑等器官出现出血及炎症；分离菌株JZXW0103具有弱生物被膜形成能力，携带有bla_TEM、aadA1和aadA2等9种耐药基因，对氨苄西林、头孢他啶和苯唑西林等10种抗菌药物具有耐药性，对青霉素、头孢噻肟和头孢哌酮等11种抗菌药物及中药全蝎敏感。【结论】本研究分离到1株ST25型猪链球菌血清2型，其具有一定致病性和多重耐药性，研究结果为猪链球菌感染的防控提供参考依据。

关键词: 猪链球菌血清2型; ST25; 多位点序列分析; 致病性

Abstract: 【Objective】 This study aimed to identify the cause of a respiratory disease outbreak in pigs at a breeding enterprise in Jingzhou city,Hubei province,and analyze the biological characteristics of the pathogenic bacteria,thereby providing a theoretical foundation for the prevention and control of swine diseases. 【Method】 PCR was used to screen common pathogens of swine respiratory diseases in the clinical samples,such as Streptococcus suis,Pasteurella multocida,and Porcine reproductive and respiratory syndrome virus (PRRSV).Bacterial isolation was performed on nasopharyngeal swabs from diseased pigs.The isolated strain was identified for serotype and molecular typing through morphological characteristic identification,16S rRNA gene phylogenetic analysis,and multilocus sequence typing (MLST).The pathogenicity and drug resistance of the isolated strain were analyzed by virulence gene detection,artificial mouse infection test,biofilm formation ability determination,drug resistance gene detection,as well as antimicrobial and traditional Chinese medicine susceptibility tests. 【Result】 The pathogen screening results showed that the diseased pigs were positive for Streptococcus suis,while other pathogens such as Pasteurella multocida and PRRSV were negative.One dominant bacterial strain was successfully isolated from the nasopharyngeal swabs of the diseased pigs.Morphological identification indicated it was a Gram-positive Streptococcus,and 16S rRNA gene phylogenetic analysis revealed that the isolated strain clustered with Streptococcus suis,thus identifying it as Streptococcus suis and named JZXW0103.Serotype identification and MLST analysis confirmed that the isolated strain JZXW0103 was ST25 Streptococcus suis serotype 2.The isolated strain carried virulence genes including mrp,sly,orf2,gapdh and sao,exhibited β-hemolytic activity,and could cause hemorrhage and inflammation in organs such as liver,lung and brain of infected mice.The isolated strain JZXW0103 had weak biofilm-forming ability,carried 9 drug-resistant genes including bla_TEM, aadA1,aadA2,etc.,was resistant to 10 antimicrobial agents such as ampicillin,ceftazidime and oxacillin,and was sensitive to 11 antimicrobial agents including penicillin,cefotaxime,cefoperazone,etc.,as well as the traditional Chinese medicine Scorpio. 【Conclusion】 In this study,one strain of Streptococcus suis serotype 2 belonging to ST25 was successfully isolated,which had certain pathogenicity and multiple drug resistance,providing a reference for the prevention and control of Streptococcus suis infection.

Key words: Streptococcus suis serotype 2; ST25; MLST; pathogenicity

中图分类号:

S852.61

项维, 何伊妍, 何斌, 陈石, 李碧波, 吴利军, 雷连成, 张付贤. 1株猪源ST25型猪链球菌血清2型的分离鉴定及生物学特性研究[J]. 中国畜牧兽医, 2025, 52(12): 5979-5992.

XIANG Wei, HE Yiyan, HE Bin, CHEN Shi, LI Bibo, WU Lijun, LEI Liancheng, ZHANG Fuxian. Isolation,Identification and Biological Characteristics of a Strain of Porcine ST25 Streptococcus suis Serotype 2[J]. China Animal Husbandry & Veterinary Medicine, 2025, 52(12): 5979-5992.

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