兰州市不同毒力基因型志贺菌致病力研究

目的检测2007年兰州市分离的不同毒力基因型志贺菌株致病力情况,探讨毒力基因型与致病力的关系。方法选用不同毒力基因型的志贺菌,以腹腔注射为感染途径,测定其对昆明种小鼠的半数致死量(LD50)。结果7株不同毒力基因型(分别为virA+ipaH+setlA、virA+ial+ipaH+setlA+setlB+sen、virA+setlA、virA+ial+ipaH+setlA+sen、virA+ipaH+setlA+sen、virA+ipaH+setlA+setlB、virA+ial+ipaH+setlA+setlB)志贺菌LD50分别为:1.422×109cfu/mL、6.653×107cfu/mL、6.653×108cfu/mL、1.422×109cfu/mL、1.422×109cfu/mL、6.653×108cfu/mL、3.062×109cfu/mL;结果表明,不同毒力基因型的志贺菌之间存在致病力差异,其中以基因组合为virA+ial+ipaH+setlA+setlB+sen的福氏志贺菌Ⅳ菌株的LD50最小,致病力最强。结论志贺菌的毒力基因型与致病力密切相关。

The pathogenicity of Shigella isolates with different virulence genotypes demonstrated in Lanzhou city

To determine the relationship of the Shigella strains isolated in Lanzhou city with different virulence genotypes to the pathogenicity of these isolates,7 strains isolated in 2007 with different virulence genotype were chosen for study and their LD50 were tested in mice of Kunming strain through intraperitoneal route.It was found that the LD50s of these 7 strains,i.e.virA+ipaH+setlA,virA+ial+ipaH+seltA+setlB+sen,virA+setlA,virA+ial+ipaH+setlA+sen,virA+ipaH+setlA+sen,virA+ipaH+setlA+setlB and virA+ial+ipaH+setlA+setlB,were 1.422×109 cfu/mL,6.653×107cfu/mL,6.653×108cfu/mL,1.422×109cfu/mL,1.422×109cfu/mL,6.653×108cfu/mL and 3.062×109cfu/mL respectively.These results indicate that different pathogenicity exists in Shigella strains with different genotypes,among which the Shigella flexneri IV strain with genotype of virA+ial+ipaH+setlA+setlB+sen shows the strongest pathogenicity,suggesting a correlation between pathogenicity of Shigella strains and their virulence genes.