2006-2017年四川省临床分离猪链球菌2型的病原学特征

Pathogenic features of Streptococcus suis serotype 2 isolated from clinical patients in Sichuan Province in 2006-2017

目的了解四川省2006-2017年临床分离猪链球菌2型的病原学特征。方法对2006-2017年四川省临床分离的28株猪链球菌2型进行毒力基因检测、药物敏感性分析、脉冲场凝胶电泳分析(PFGE)。结果28株猪链球菌2型分为2种毒力基因型,1株为cps2J+/mrp-/sly+/gapdh+/ef+型别,其余均为cps2J+/mrp+/sly+/gapdh+/ef+型别;药敏检测结果显示,28株猪链球菌对第三代、第四代头孢菌素类、碳青霉烯类、青霉素、左氧氟沙星、利奈唑胺、万古霉素、氯霉素、达托霉素均敏感,对四环素均耐药。28株猪链球菌中,仅2株对克林霉素、阿奇霉素、红霉素耐药,其余均敏感。PFGE分析结果显示,28株猪链球菌呈现6种PFGE图谱,相似性为76%,其中23株是完全相同的图谱,占82.14%;2006-2007年分离的19株菌呈现完全相同的PFGE图谱,2010年后分离的9株呈现出6种PFGE图谱。结论2006-2017年四川省临床分离猪链球菌2型流行株的毒力基因型主要为高致病性cps2J+/mrp+/sly+/gapdh+/ef+型别,对β-内酰胺类药物敏感,2006、2007年不同市区临床分离的猪链球菌2型为统一来源,2010年后分离的菌株PFGE图谱相似度较低。

This study aimed to analyze the pathogenic features of Streptococcus suis serotype 2(SS2)isolated in Sichuan province between 2006 and 2017.Virulence gene detection,antimicrobial sensitivity analysis and pulsed field gel electrophoresis analysis were performed for 28 strains of SS2 isolated from clinical patients in Sichuan province during 2006-2017.The 28 strains of SS2 were divided into two virulence genotypes:cps2J+/mrp-/sly+/gapdh+/ef+and cps2J+/mrp+/sly+/gapdh+/ef+.Drug sensitivity test results showed that all strains were susceptible to third and fourth generation cephalosporins,carbapenems,penicillin,levofloxacin,linezolid,vancomycin,chloramphenicol and daptomycin,but resistant to tetracycline.Among the 28 strains of SS2,26 strains were sensitive to azithromycin,erythromycin and clindamycin,and two strains were resistant to azithromycin,erythromycin and clindamycin.Among the 28 strains of SS2,six PFGE patterns were found,and the sequence similarity was 76%.A total of 23 strains of SS2 had identical PFGE patterns,accounting for 82.14%.The PFGE patterns of 19 strains isolated in 2006 and 2007 were fully consistent.A total of nine strains isolated in 2010-2017 showed six PFGE patterns.From 2006 to 2017,the prevailing strain of SS2 in Sichuan province was highly virulent,had the cps2J+/mrp+/sly+/gapdh+/ef+genotype and was sensitive toβ-lactam drugs.From 2006 to 2007,the clinical isolates of S.suis serotype 2 from different urban areas in Sichuan Province had the same source.The PFGE patterns of strains isolated after 2010 had low similarity.