| Background and ObjectivesMycobacterium tuberculosis(MTB) is one of the main pathogens that cause health effects. Beijing family is the main genotype that cause tuberculosis transmission in our country. Because multi-drug resistant Beijing genotype mycobacterium tuberculosis has repeatedly caused outbreak in history, it makes the correlation between Beijing strain and drug resistance has become the hotspot. some effective molecular genotype methods are set up and applied to TB molecular epidemiology monitoring. It will help accurately identify the outbreak of tuberculosis,prevalence and make effective prevention and control measures.Spoligotyping techniques become the preferred method of detecting mycobacterium tuberculosis complex and genotyping in recent years. The basic principle of this method is based on the direct repeat region (DR region) polymorphism. DR region only present in the M. tuberculosis complex group. Composed by a number of conservative length 36bp direct repeat sequences and separated by non-repeat sequence that is spacer, each 34-41bp in length. The presence or absence in the DR region of 43 spacers of known sequence can be detected by hybridization of PCR-amplified spacer DNA to a set of immobilized oligonucleotides, more specific results can be received through enhanced chemiluminescence detection system. Usually the order of spacer is the same in all strains, but may occur for a particular spacers insertion or deletion, Therefore, use of Spoligotyping for Mycobacterium tuberculosis can be conducted on the strain identification.Characteristics of Mycobacterium tuberculosis genotype,the prevalence of Beijing family,age distribution characteristics and regional genotype distribution characteristics of different genotypes by using Spoligotyping in henan. We can evaluate its value for TB control In the future.Meterials and MethodsM.tuberculosis clinical isolates selected from Henan province randomly were cultured with Lowenstein-Jensen medium. The bacteria from which the genome DNA was extracted were collected. The clustering of genotype was analyzed on http://www.miru-vntrplus.org/MIRU/index.faces website. Chi-Square test was used for statistical analysis.ResultsThe Spoligotyping pattern of 344 M.tuberculosis clinical isolates were analyzed respectively. The clustering of genotype showed that these strains could be categorized into 4 gene clusters(Beijing and Beijing like,T,Manu,S)and 24 genotypes.299 strains were Beijing family genotype accounting for 87.7% (299/341).There is no statistical significance between drug resistance and Beijing family (X2=1.46,p>0.05. The Beijing family genotype proportion in younger groups is higher than the older groups. The association between young age and Beijing strains was even stronger in younger ages(X2=32.053,p<0.001).There are different characteristics of Beijing family genotype isolated in different regions.Conclusion1 Beijing family is the dominant Genotype of the M.tuberculosis in Henan, accounting for 87.7%(299/341).T cluster account for 10.9%.Other genotypes such as Manu2 cluster,S cluster and LAM3 cluster and so on was account for 1.49%.2 There is no correlation between drug-resistance and Beijing family genotype.3. The correlation between Beijing family and age is significant. The proportion of Beijing family genotype of<60-year old group is higher than> 60-year old group(X2=32.053, p<0.001).It indicates that recent transmission of Beijing family genotype in this area is widely popular.4. The association between Beijing family and age is statisticly significant by X2 test. These differences may suggest us to focus on Beijing family genotype when monitoring outbreak and prevalence of mycobacterium tuberculosis in these areas. |
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