2005—2018年福建省人感染猪链球菌分离株特征分析

Characteristic of Streptococcus suis isolated from human infected cases in Fujian Province,2005—2018

目的探讨2005—2018年福建省分离到的猪链球菌的分子流行病学特征。方法通过对2005—2018年疫情分离的猪链球菌菌株进行相关常规分离培养、生化鉴定及药物敏感实验、基质辅助激光解析电离飞行时间质谱(matrix-assistedlaserdesorption/ionizationtime-of-flightmassspectrometry,MALDI-TOF MS)及聚合酶链式反应(polymerase chain reaction,PCR)检测猪链球菌相关的16S rRNA基因和部分毒力基因荚膜多糖(capsularpolysaccharide2J,cps2J)、溶菌酶释放蛋白(muramidase-releasedprotein,mrp)、溶血素(suilysin,sly)、胞外因子(extracellular protein factor,ef),同时检测猪链球菌7个管家基因(aro A、cpn60、dpr、gki、mut S、rec A、thr A)分析菌株相关的多位点序列分型(multilocus sequence typing,MLST)型别。结果10株菌株经鉴定均符合猪链球菌2型,16S rRNA基因和质谱鉴定均可鉴定到猪链球菌种水平,10株菌株对氯霉素、四环素、红霉素、庆大霉素等均出现不同程度耐药现象;毒力基因携带模式以cps2J+ef+mrp+sly+/cps2J+ef+mrp+sly-/cps2J+ef+mrp-sly-/cps2J+ef+mrp-sly+多种模式并存。aro A-cpn60-dpr-gki-mut S-rec A-thr A基因等位基因谱为1-1-1-1-1-1-3,MLST分型均为ST7,而质谱聚类能将10株菌株分为3个不同的聚类型。结论福建省存在散发的猪链球菌2型感染病例,其主要为ST7且毒力基因携带模式具有多样性;MALDI-TOF MS在猪链球菌鉴定及蛋白聚类分型方面具有一定的快速、简便应用价值。

Objective To investigate the molecular epidemiological characteristics of Streptococcus suis isolated in the period from 2005 to 2018 in Fujian Province.Methods Routine isolation and culture,biochemical identification and drug sensitivity test,matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS),and polymerase chain reaction(PCR)were performed on Streptococcus suis strains collected in the laboratory from 2005 to 2018 to detect Streptococcus suis-related 16SrRNA gene and some virulence genes encoding capsular polysaccharide 2J(cps2J),muramidase-released protein(mrp),suilysin(sly),extracellular protein factor(ef).Meanwhile,7 housekeeping genes(aroA,cpn60,dpr,gki,mutS,recA,thrA)of S.suis were detected for the multilocus sequence typing(MLST)of the strain.Results All the 10 strains were identified as Streptococcus suis type 2,and the 16SrRNA gene detection and mass spectrometry both identified the bacterial species being Streptococcus suis.The 10 strains showed different degrees of drug resistance to chloramphenicol,tetracycline,erythromycin,and gentamicin,etc.The virulence pattern was cps2J+ef+mrp+sly+/cps2J+ef+mrp+sly-/cps2J+ef+mrp-sly-/cps2J+ef+mrp+sly-.Alleles of aroA-cpn60-dprgki-mutS-recA-thrA gene were 1-1-1-1-1-3,MLST types were ST7,and the 10 strains could be classified into three different clustering types by mass spectrometry.Conclusions Sporadic Streptococcus suis type 2 infection in Fujian Province was mainly ST7,with diverse virulence pattern.MALDI-TOF MS may provide rapid and simple identification and protein clustering of Streptococcus suis.