Genotyping and transmission chain analysis of Mycobacterium leprae in Xingyi city,Guizhou province

ObjectiveTo explore genotypes and transmission characteristics of Mycobacterium leprae(M leprae).MethodsThe M leprae strains isolated from skin biopsies of 50 new or relapse leprosy patients during 2004 to 2009 in Xinyi city were genotyped on 17 various number tandem repeat(VNTR) loci and their transmission chains were analyzed based on epidemiologic information.ResultsThe M leprae strains were grouped into 6 clusters according to 17 alleles genotypes including AC8b,AC9,and AC8a.All the clusters had same copies on loci of rpoT,21-3,27-5,23-3,and (GGT) 5 completely.However,2nd and 5th clusters presented unique genotypes with special 4 copies on locus 12-5 and 18-8,respectively.Among 26 cluster strain infected patients,21 patients (including 7 relapses) showed clear infection transmission chain of leprosy.The 15(57.7%) patients infected by lst or 4th clusters were mainly distributed in south-east of Xingyi city.Most patients with infection of 4th cluster derived from Buyi minority patients living in a same village.Meanwhile,family patients were detected to be infected by different genotypes of M leprae.ConclusionLong coexisting of diversity and unique M leprae clusters resulted in high prevalence of leprosy in Xingyi.Family members,susceptible to leprosy,could be infected by different genotypes of M leprae in surrounding enviroment.Early patient detection and implementation of chemoprevention should be strengthened to block the transmission of leprosy among family members and villagers in high prevalent areas.