云贵川三省麻风菌株基因分型的比较研究

目的:了解云南、四川、贵州三省麻风菌株基因型的地理分布。方法:从云南省丘北县、四川省凉山州、贵州省兴义市分别采集59、21、31例麻风患者皮损活检,提取麻风菌DNA,对6-7、AC9、GTA9 3个数目可变的串联重复(variable-number tandem repeat,VNTR)位点的PCR产物测序,确定各位点重复序列数进行分型。结果:三省在6-7位点上有5种基因型,云南以7个拷贝的基因型为主,其它两地区的菌株在该位点的等位基因型为7、8、9,其分布无显著性差异。AC9位点上有4种基因型,三省均以8个拷贝的基因型为主。GTA9位点有非常明显的多样性。云南GTA9为9个拷贝的菌株占总菌株数的18.18%。结论:本研究结果提示麻风菌的基因型与地理分布有关。但需要以更多的位点,了解以VNTR为主的基因分型能否应用于麻风病的传染源和传播链的流行病学研究。

Preliminary study on strain genotyping of Mycobacterium leprae collected from Yunnan, Sichuan and Guizhou Provinces

Objective: To determine the geographic distribution of M.leprae genotypes collected from Yunnan,Sichuan and Guizhou Provinces.Methods: DNA extracted with variable-number tandem repeat(VNTR) from skin biopsies collected from 59 leprosy cases in Qiubei County,Yunnan,21 cases in Liangshan,Sichuan and 31 cases in Xingyi City,Guizhou.PCR products based on 6-7,AC9 and GTA9 loci were subjected to DNA sequencing for determining the number of repeats.Results: Locus 6-7 of M.Leprae collected in the three provinces had 5 alleles.The dominant allele was 7 copies in Qiubei County,Yunnan,while the dominate alleles of M.Leprae collected in Sichuan and Guizhou were 7,8 and 9.There was no significant difference in the geographic distribution between the two provinces.Locus AC9 had 4 alleles and 8 copies' allele was dominant in the three provinces.Locus GTA-9 demonstrated a great genetic diversity.But the locus GTA-9 accounted for 18% of the stains of M.Leprae in Yunnan Province.(Conclusion): The results of the current study demonstrate that there is geographic distribution of genotypes of M.leprae.However,more loci are needed to study whether genotyping of M.leprae,based on VNTR,can be used in the study on the transmission of M.leprae.