Analysis on genetic diversity of Mycobacterium tuberculosis isolates from Tibetan patients in Tibet by spacer oligonucleotide typing / 中华传染病杂志

ABSTRACT

Objective To detect the genetic diversity and prevalent strains of Mycobacterium tuberculosis isolates from Tibetan patients in Tibet and to analyze factors associated with prevalent strains.Methods A total of 577 Mycobacterium tuberculosis isolates were genotyped by spacen oligonucleotide typing (spoligotyping) and the results were analyzed with BioNumerics software (Version 5.0) and compared with the international spoligotype database of SITVIT2.Results Among the 577 cases of Tibet patients,329 were male and 248 were female.Based on spoligotyping,23 different spoligotypes were identified among 577 Mycobacterium tuberculosis isolates,with a genetic diversity of 3.99 ％.The majority (97.57％,563/577) of the isolates belonged to four known families,such as Beijing family,T family,CAS family and MANU2 family.The remaining 14 isolates had 11 novel spoligotypes.522 (90.47％)isolates belonging to Beijing family presented with 7 spoligotypes,resulting in the genetic diversity of Beijing family of 1.34％.With high similarity,Beijing family strains could be clustered into one genotype;among non-Beijing family strains,strains belonging to T family and MANU2 family were similar and could be clustered into one genotype.Changdu had the highest prevalence (97.83％) of Beijng family strains.In this study,the occurrence of Beijing family strains was not associated with age,sex,bacillus CalmetteGuerin vaccination or treatment history (P=1.00,0.36,0.83 and 1.00,respectively).Conclusions In this study,the genetic diversity of Tibetan Mycobacterium tuberculosis is low and Beijing family strains are highly prevent in Tibet,by classical spoligotyping.