猪链球菌2型的鉴定及其毒力因子检测

Identification of Streptococcus suis serotype 2 and test of the virulent factors genes

猪链球菌的感染不仅对养猪业造成巨大的损失,同时对公共卫生尤其是相关从业人员的生命造成威胁,严重感染引起死亡。根据参考文献,设计了1对猪链球菌2型特异性引物。对四川分离的7株链球菌、江苏分离的1株、北京分离的6株和菌种中心保存的5株C群马链球菌兽疫亚种、1株D群链球菌、4株R型链球菌、2株S群链球菌和E、F、G、K、L、M、N、O、P群链球菌各1株进行了检测。结果7株四川分离株均为2型;1株江苏分离株为2型;6株北京分离株有3株为2型;1株R群、2株S群链球菌为2型猪链球菌。对检测出的14株猪链球菌2型的毒力因子做进一步检测。MRP基因检出率为92.9%(13/14);EF基因检出率为100%(14/14);sly基因检出率为71.4%(10/14);Cps2A基因检出率为92.9%(13/14);gapdh基因检出率为64.3%(9/14);FBPS基因检出率为92.9%(13/14);orf2基因检出率为71.4%(10/14)。毒力因子全为阳性的菌株有6株,MRP-EF+菌株有2株。本研究从259份健康猪扁桃体中分离到16株2型猪链球菌,健康猪带菌率为6.2%(16/259)。16株猪链球菌2型中,MRP、EF、Cps2A全为阴性,只从1株2型猪链球菌中检测到了sly基因(1/16);gapdh基因检出率为56.25%(9/16);FBPS基因检出率为75.0%(12/16);Orf2基因检出率为37.5%(6/16)。

Streptococcus suis serotype 2 is the causative agent of a wide range of infections in pigs such as septicemia, meningitis,arthritis, and pneumonia. This particular serotype has also been associated with severe infections in humans. According to the references,a pair of primers was designed and synthesized. Streptococcus suis serotype 2 was identified from Streptococcus isolated from Sichuan,Jiangsu, Beijing, Streptococcus equi subsp, group C, Streptococcus group D, E, F, G, K, L, M, N, O, P. There were 14 strains Streptococcus suis serotype 2. Virulent factors genes were tested by PCR. The percent of MRP,EF,sly,cps2A,gapdh,FBPS and orf2 was 92. 9% （13/14）, 100% （14/ 14） ,71.4%（10/14）,92.9%（13/14）,64.3%（9/14）,92.9%（13/14） ,71.4%（10/14） ,respectively. 16 strains Streptococcus suis serotype 2 were isolated from 259 health pigs. The percent of isolation from health pigs is 6.2% （16/ 259）. All these Streptococcus suis serotype 2 were belonged to MRP EF^- cps2A phenotype. Sly gene was tested only in one strain Streptococcus suis serotype 2. The percent of gapdh,FBPS and orf2 was 56.25% （9/16）, 75.0% （12/16） ,37.5% （6/16） ,respectively.