变链素活性与变形链球菌基因多态性的关系研究

A study on relationship between genotypic diversity and mutacin activity of mutans streptococci

目的探讨变链素的活性与变形链球菌（MS）基因多态性的关系。方法在AP-PCR基因分型的基础上,选择来自单基因型定植的个体50株MS为单基因型组,另50株来自多基因型共同定植的个体为多基因型组,用平板法检测2组菌株产生变链素对10个指示株的抑制情况,T-检验比较2组菌株抑菌环和抑菌谱的均数差异。结果所有的实验株（100%）均可产生抑制6-8个指示株的变链素,抑菌环和抑菌谱在不同个体之间变异,组间均数的比较不具有显著性（P值分别是0.12,1.79）。结论多基因型MS定植的口腔,在产生变链素方面似乎不具有优势。

Objective To evaluate the relationship between genotypic diversity and mutacin activity of mutans streptococci（MS）. Methods A total of 100 mutans streplococci isolates with distinct AP-PCR genotypes were divided into two groups,including 50 isolates from 10 subjects harbored one type MS and 50 isolates from 10 subjects harbored more types MS. Then the ability of the isolates to produce mutacins was tested by the stab culture technique against 10 indicator strains. T-test was used to analyze the difference in spectrum and the sizes of inhibition zone between two groups. Results The mutacina were produced by all of the strains against 6 to 8 indicator strains. The spectnmi of inhibitory activity and the inhibition zone size varied among 20 subjects. On average, the difference within two groups was insignificant（ P = 1.79, 0.12）. Conclusion It seems that the niche harbored with different genotypes MS did not confer an advantage in levels of mutacin activity.