Abstract: Streptococcus suis（SS）is an important zoonotic pathogen. Slaughterhouses serve as a critical link between pig farming and meat consumption，making epidemiological investigations of SS of significant public health importance. In 2024，an SS strain was isolated from tonsillar samples of healthy pigs at a slaughterhouse in Guangdong Province. The isolate was identified as serotype 2 through 16S rRNA sequencing and serotyping. Subsequent analyses included virulence gene detection， antimicrobial susceptibility testing （AST） ， and in vivo pathogenicity assessmenassessment in mice. The isolate carried six virulence genes：gapdh，gdh，srtA，ccpA，orf2，and sly. AST revealed resistance to 11 antibiotics，including spectinomycin，lincomycin，and tetracycline，indicating that the strain is multidrug?resistant（MDR）. The median lethal dose（LD50）of the isolate was determined to be 4.64×108 CFU，and infection with the strain induced varying degrees of pathological lesions in the heart，liver，spleen，lungs， and kidneys of mice. These findings provide a theoretical basis for understanding the epidemiology of SS in Guangdong and inform its prevention and control，with significant public health implications.

Key words: Streptococcus suis serotype 2；Slaughterhouse；Isolation and identification；Pathogenicity；Public health

摘要： 猪链球菌（Streptococcus suis，SS）是一种重要的人兽共患病原菌，屠宰场作为养殖与 消费的关键连接环节，猪链球菌流行病学调查具有重要的公共卫生意义。2024年，该研究从广 东某屠宰场健康猪扁桃体样品中分离到一株猪链球菌，16S rRNA及血清型鉴定结果显示，分 离菌株为2型猪链球菌。对分离菌株进行毒力基因检测、药物敏感性试验及小鼠致病性试验。 研究结果显示，分离菌株携带gapdh、gdh、srtA、ccpA、orf2、sly6 种毒力基因。药物敏感性试验结 果显示，分离菌株对大观霉素、林可霉素、四环素等11种抗生素耐药，为多重耐药菌。小鼠致 病性试验结果显示，分离菌株对小鼠的半数致死量（LD50）为4.64×108 CFU，分离菌株感染可诱 导小鼠心脏、肝脏、脾脏、肺脏和肾脏等脏器出现不同程度病变。该研究结果为深入了解广东 猪链球菌流行情况及猪链球菌防控提供理论参考，同时具有重要的公共卫生意义。

关键词: 2型猪链球菌；屠宰场；分离鉴定；致病性；公共卫生