Distribution and characteristics on species of Mycobacterium leprae in China / 临床检验杂志

ABSTRACT

Objective To realize the distribution and characteristics of Mycobacterium leprae (M.leprae) species and its single nucleotide polymorphisms (SNPs) spreading currently in China.Methods A total of 171 cutaneous lesion specimen of leprosy patients from 22 provinces were collected.The 16S rRNA conservative region of Mycobacterium leprae was amplified by nest PCR and the positive products were sequenced directly and aligned by BLAST.The SNPs of M.leprae were genotyped by restricted fragment length polymorphism for the PCR products.Results The 171 specimen were all Mycobacterium leprae since the amplified fragments of DNA samples were 99％ similar to the Br4923 of M.leprae from Brazil.No new species (M.lepromatosis) was found.Among the 85 samples genotyped for SNPs,SNP3,SNP1 and SNP2 accounted for 78.8％ (67/85),20％ (17/85) and 1.2％ (1/85) respectively.There was no sample with SNP4 genotype to be detected.Among the 171 sequencing specimen,130 showed mutation C-T at 251 bp of 16S rRNA.There was no difference for mutant rate of 16S rRNA gene and SNP genotype among the samples with different clinical pathological types.Certain associations between 16S rRNA C251T mutation and SNP genotype were found.Most of the samples with C251T mutations of 16S rRNA sequence were SNP3,only a few were SNP1 but not SNP2.There was significant difference of SNP genotype distribution among the patients from different regions.The distribution rate of SNP3 genotype in the samples from inland region (97.1％,34/35)was significantly higher than that from coastal region (66％,33/50) (x2 =11.96,P ＜ 0.01) . There was significant difference of the gene mutation rate of 16S rRNA sequence among the patients from different regions.The mutation rate of 16S rRNA in the samples from inland region (94.8％,92/97) was significantly higher than that from coastal region (51.4％,38/74) (x2 =43.56,P ＜0.01).Conclusion C251T mutation in 16S rRNA gene sequence of M.leprae may associate with SNP type suggesting that the characteristics of geographical distribution presented in different genotypes of M.leprae.No new species of M.leprae was found in this study.