我国伤寒沙门氏菌的分子流行病学特征Ⅰ．我国部分地区伤寒沙门氏菌的多位点酶电泳研究

Molecular Epidemiological Characteristics of Salmonella typhi Strains lsolated in China l.Analysis of Salmonella typhi Strains lsolated in Chha by Multilocus Enzyme Electrophoresi

通过聚丙烯酰胺凝胶电泳（ＰＡＧＥ）分析了我国部分伤寒高发省份在不同年代分离到的３３５株伤寒菌的七种染色体编码的多位点代谢酶。结果发现这七个酶位点均有多态性。其平均等位基因数为７．４（２～１９）；平均遗传多态度为０．４９８（０．１９８～０．８８３）。３３５株伤寒菌的七个酶位点电冰结果通过排序和数值分类可分为１４７个不同的电泳型（ＥＴｓ）．根据对ＥＴｓ进行聚类分析以及聚类时不相似系数曲线变化情况，把１４７个ＥＴｓ归属于２２个不同的亚克隆系，１２个克隆系，进一步的分析发现，不同地区、不同年代、不同来源的菌株有其规律性，１９８８年的江苏、浙江菌株大部来自同一克隆系；１９９０年的广西菌株和１９９０年的部分湖北菌株也为同一个克隆系菌株。不同年代分离的湖南和贵州菌株之间具有较近的亲缘性；而新疆菌株则有相对的独立性。同时结果还显示同一次伤寒爆发或流行中分离到的菌株均来自一个亚克隆系。

Multilocus enzyme analysis by polyacry1a-mide gel electrophoresis( PACE)was usedto analyse 335 isolates of S,typhi fromseveral provinces where high morbidity of ty-phoid fever was observed in recent years. We analysed 7 metabolic enzymes encoded by chromosome,The results showed that all the enzyme loci were polymorphic.The average alleles per locus was 7.4(2-19):the mean genetic diversity per locus was 0.498(0.198 0.883).There were 147 distinctive electropho- retic types( ETs)in 335 isolates.With cluster analysis by the averagn-linkage me-thod.we found that there were 22 subclcnes,12 clones among all isolats studied.Most isolates in 1988 from both Jiengsu and Zhe- jiang provinces belonged to one clcne the isolates from Guangxi Province in 1990 and parts of Hubei isolates belonged to one clone; isolates from Hunan and Guizhou province s during several-year period were homogeneous. Howevet,the isolates from Xin- jiang Autonomous Region were remarkebly different from other provinces,beloning to a particular clone,We also observed that the isolates from an outbreak or epidemic were from a one subclone.