Molecular Characterization of Virulence Plasmid in Shigella Species

本室由高雄地區一些新生兒及嬰兒急性細菌性腹瀉患者的糞便中，分離出了121株志賀氏桿菌，由血清學分群的結果發現S. flexneri和S. sonnei是臨床上引起Shigellosis的主要致病菌另外由具有侵犯性的S. flexneri有一大小約123 Mdal的共同質體存在。而存於具侵犯性的S. sonne中共有的質體，其分子量大小約為110Mdal，同時發現這些菌株於失去此大質體同時，也失去了侵犯力。為了證明這兩個分子量頗大的質體致病力的關係，吾人藉Tn5接合於此二質體上提供一可供篩選的標幟，同時在移動性質體的協助下，將此二質體轉移入E. coli K-1214R525和不具侵犯性的Shigella菌體內。由Transconjugants獲得了造成天竺鼠眼睛結膜炎的能力，並得以穿入HeLa及HEp-2等上皮細胞的結果可知；此二質體的存在，確實與志賀氏桿菌的侵犯性有著密切的關連，然而由腸毒去的分析發現，此二質體與腸毒素的產生，並沒有明顯的關係存在。

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並列摘要

The one hundred and twenty-one Shigella isolates were studied to determine whether plasmids are involved in causing virulence. Nine of the fifty-two Shigella flexneri isolates which were found to harbor a large plasmid, 123 megadaltons in size, were able to produce Keratoconjunctivitis in guinea pigs and invade Hela cells. In Shigella sonnei, the virulent plasmid was defined to be 110 megadaltons. Cured strains of Shigella flexneri and Shigella sonnei lost their ability to invade. To monitor plasmid transfer, the large plasmid was tagged with Kanamycin resistant transposon Tn5. These tagged plasmids were not self-transferrable, but were mobilized by conjugative plasmid into avirulent strains of E. coli and Shigella. Transconjugants of both strains which had received large plasmid were able to gain invasion. This study directly demonstrates that large plasmid encode some functions required for epithelial cell penetration. However, these plasmids were not involved in producing cytotonic and cytotoxic enterotoxin.

並列關鍵字

virulence plasmid ； Shigella flexneri ； Shigella sonnei

國際替代計量

Molecular Characterization of Virulence Plasmid in Shigella Species

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