不典型山夫登堡沙门菌流行菌株的鉴定

Identification on the epidemic strains of atypical Salmonella enterica subsp.enterica serovar Senftenberg

目的对新出现的硫化氢(H2S)阴性山夫登堡沙门菌流行菌株进行鉴定。方法比较腹泻患者分离的山夫登堡沙门菌落、生化、耐药表型和沙门菌毒力岛1(SPI-1)的编码基因表型(hilA、invA),使用Riboprinter(进行核糖体指纹图谱分型,脉冲凝胶电泳(PFGE)选用XbaⅠ限制性内切酶,聚类软件选用BioNumerics软件。结果 2006年30株山夫登堡沙门菌腹泻菌株中,确认12株属于H2S和hilA、invA基因均阴性的表型不典型菌株;所有菌株除对四环素有较高耐药性(75.6%)外,对其他测试抗菌药物均较敏感;Riboprinter(核糖体分型图谱证实不典型与典型山夫登堡沙门菌在遗传学上属独立的克隆;PFGE分型将34株腹泻株分成16个带型,11株不典型菌株间存在90%的遗传学同源,优势带型为6型(6株)和4型(3株);13株典型菌株间有80%的遗传学同源,优势带型为17型(5株)、23型(5株)和11型(3株),不典型与典型菌株分别聚类成2个克隆族。结论生化、基因表型和遗传学特征不典型的山夫登堡沙门菌构成了2006年上海市山夫登堡的多点暴发病例,建议使用经过优化的常规和分子生物学方法以避免临床实验室对表型不典型沙门菌株的漏检。

Objective To identify new epidemic strains of Salmonella enterica subsp.enterica serovar Senftenberg（Salmonella Senftenberg） with H2S negative.Methods The isolates of Salmonella Senftenberg from diarrheal patients were identified by colony morphology,biochemical character,antibiotic resistant phenotyping and encoding gene（hilA and invA） of Salmonella pathogenicity island 1（SPI-1）.Riboprinter for typing ribotyping profiles and XbaⅠrestriction enzyme for pulsed-field gel electrophoresis（PFGE） were used.The results of genotyping were analyzed by BioNumerics software.Results Among 30 strains of Salmonella Senftenberg from diarrheal patients in 2006,there were 12 strains of atypical strains which H2S and hilA,invA gene were negative.These strains were susceptible to many antibiotics except tetracycline（75.6%）.Using Riboprinter ribotyping profiles,there were two strains,atypical Salmonella Senftenberg strain and typical Salmonella Senftenberg strain,which expressed independent clone in genetics.34 strains of Salmonella Senftenberg were divided into 16 PFGE type patterns.Among 11 atypical strains,there were 90% homologous strains in genetics.The dominant band types were Type 6（6 strains） and Type 4（3 strains）.Among 13 typical strains,there were 80% homologous strains in genetics.The dominant band types were Type 17（5 strains）,Type 23（5 strains） and Type 11（3 strains）.Atypical strains and typical strains were two different clone clusters.Conclusions Salmonella Senftenberg with atypical biochemical reactions,phenotype and genetic character contributes to outbreak on multiple sites of Shanghai in 2006.To prevent from missing the phenotype of atypical Salmonella,the optimum routine method and molecular biology method should be used.