[Genotyping of Mycobacterium leprae in Guangdong province].
OBJECTIVE: To understand the genotypes of Mycobacterium leprae collected from Guangdong province, China and to analyze the routes of leprosy transmission both inside and outside of Guangdong. The impact of emigrant leprosy patients to the endemic nature of the disease in Guangdong was also studied.
METHODS: Typing on strains with variable number of tandem repeats (VNTR) and single nucleotide polymorphism (SNP) were performed on the local cases and emigrant cases based on skin biopsy.
RESULTS: Most isolates from local patients belong to SNP type 1 and SNP type 3 isolates were found just in a small part of local isolates. However, all the emigrants were carrying SNP type 3. Within the SNP type 1 strain from Guangdong, alleles at the 18-8, 12-5, ML-1, (TA) 10 and (GGT) 5 differed from SNP 3 strains collected from other areas in China. However, all the SNP type 1 and SNP type 3 local isolates identified from Guangdong were having close VNTR profiles and the main differences appeared in the alleles at ML-1, (TA) 10 and (GGT) 5.
CONCLUSION: The transmission of strain with SNP type 1 seemed to be associated to the "Silk Road on the Sea", calling for monitoring and confirming the transmission of patients with SNP type 3 in Guangdong were from the secondary transmission, by the emigrant patients. Further study on the historic spread and phylogenetic relationships between SNP type 1 and novel SNP type 3 in Guangdong is needed.