云南省丘北县麻风菌株基因分型研究

Study on genotyping of M.leprae in a high endemic county

目的:验证云南省丘北县麻风菌株与流行病学间的关联性。方法:对2003-2007年发现的106例新麻风患者菌株进行了6个VNTR位点分型,以系统发育树分析与流行病学的关联性。结果:丘北菌株依据(GTA)9等位基因型可分为两大菌群。第一枝由(GTA)9位点从9到13个重复数组成的A、B和C聚集株,主要分布在该县北部和西北部;第二枝由(GTA)9重复数高达20以上的D、E菌株组成,主要分布在中部和东南部。A至F聚集株内,至少有两个或以上有多个患者的家庭。第一菌群内患者间有明显的流行病学关联,但第二菌群内患者则缺乏关联性。结论:(GTA)9等位基因高度多态菌群来源与异质性的原因不清楚。以家庭和邻居关联的麻风病传播在丘北县很常见,有多个患者的家庭,感染菌株可能来自相同的传播链。

Objective： To determine the relationship between the VNTR genotype of M. leprae and epidemiology of leplvsy patients in Qiubei, an endemic County of Yunnan province, China. Methods： Genotyping six VNTR locl on 106 new patients detected during 2003 - 2007 in Qiubei were genotyped. The phylogenetic analysis through PAUP 4.0 was applied and combined w-ith epidemiology to determine the relationship between the genotyping and the transmission of the disease. Results： M. leprae in Qiubei were grouped into the two major branches depending on the alleles of （GTA） 9. One branch was consisted of 54 isolates with 9 - 13 repeat units at the （GTA） 9 locus and it was subdivided into A, B and C clusters. One repeat unit differed only in the AC9 locus between A and B clusters and A, B. The C cluster appeared to derive from a common ancestor. The second branch was consisted of 58 isolates, whose repeat units was located on （GTA） 9 with repeat units more than 20, and even 45. These were also grouped into D, E clusters. However, the preferential distribution of the M. leprae with low （GTA） 9 alleles （9 - 13 copies） was in the north and north - west townships and those with higher alleles in the south central and south-east. The isolates of B subgroup was increasing and a new subgroup F was identified in recent two years. In each of clusters A to F, there were at least two or more multi - case families. The VNTR genotypes were associated epidemiologically within patients of the first branch, but was lack of such links in the second branch. Conclusion： The origins and cause of the heterogeneity in these isolates with high allelie diversity in （GTA） 9 locus is not known though. Family and neighborhood linked transmission is common in Qiubei. The infection of M. leprae may come from the same transmission chain.