广西部分地区猪链球菌的分离鉴定及小鼠致病性研究

对来自广西边境地区部分发病猪场及屠宰场的370份猪组织进行细菌分离鉴定，共分离到16株链球菌，对这16株链球菌进行了形态学观察、PCR鉴定及小鼠致病性试验。结果表明，其形态、染色、生化特性均符合猪链球菌的特点，通过GDH鉴定与测序，证实这16株菌株均为猪链球菌，分别命名为GX1~GX16。通过特异性引物PCR分型（35个血清型），其中有1株为1型，1株为2型，1株为5型，1株为29型，5株为8型，7株未分出型。用这16株猪链球菌对昆明小鼠和BALB/c小鼠进行动物致病性试验，结果发现，菌株GX10对昆明小鼠和BALB/c小鼠致死率均为100%；菌株GX11对BALB/c小鼠致死率为80%；其他菌株对昆明小鼠和BALB/c小鼠均无致病性。菌株GX10、GX11对BALB/c小鼠的LD₅₀分别为4.5×10⁵和3.6×10⁹ CFU。本试验结果表明，广西边境地区存在致病性猪链球菌8型。BALB/c小鼠对猪链球菌的敏感性高于昆明小鼠，更适合作为猪链球菌致病性研究的动物模型。

Isolation,Identification and Pathogenicity on Mice of Streptococcus suis in Pig in Guangxi Border Area

16 strains of Streptococcus were isolated and identified from 370 pig tissues of clinically morbidity farms and slaughter houses in Guangxi border area.Morphological observation, PCR identification and pathogenicity test were carried out. The results showed that the morphology,dyeing,biochemical characteristics were coincidence with the characteristics of Streptococcus suis,confirmed that 16 strains were Streptococcus suis,and named as GX1 to GX16. Further by divided type identification (35 serotypes) by GDH,1 strains was type 1,1 strains was type 2,1 strains was type 5,1 strain was type 29,5 strains were type 8 and 7 strains could not differentiate types. The pathogenicity of 16 strains Streptococcus suis were detected by Kunming mice and BALB/c mice. The results showed that the letal rate of GX10 for Kunming mice and BALB/c mice was 100%;GX11 for BALB/c mice was 80%;Other strains were apathogenicity to the Kunming mice and BALB/c mice. The LD₅₀ of GX10 and GX11 was 4.5×10⁵ and 3.6×10⁹ CFU for BALB/c mice,respectively. The results showed that pathogenic Streptococcus suis type 8 occured in Guangxi border area. The sensitivity of BALB/c mice to Streptococcus suis was higher than Kunming mice, BALB/c mice was more suitable for the pathogenic study of Streptococcus suis.