Objective To examine the foasibility of a new method for Mycobacterium tuberculosis (M. tuberculosis)"Beijing family"strain identifjcation——RD105 deletion test. Methods Two methods,Spoligotyping and RD105 deletion test,were used for M. tuberculosis"Beijing family"strain identification,respectively. The difference of the two identification methods was compared. Results Three hundred and forty-two clinical isolates from four areas(Beijing,Fujian,Xinjiang and Jilin)were assayed in this study.Among the total samples,261 isolates belonged to"Beijing family"accounting for 76.32%,while the other 81 isolates belonged to"non-Beijing family"accounting for 23.68%. The coincidence rate for these two methods was 100%. Conclusion The simple and rapid new method——RD105 deletion test can be used to identify"Beijing family"instead of the traditional method——Spoligotyping.

Investigations on the genetic diversity of Mycobacterium tuberculosis in China have shown that Beijing genotype strains play a dominant role. To study the association between the M. tuberculosis Beijing genotype and the drug-resistance phenotype, 1286 M. tuberculosis clinical isolates together with epidemiological and clinical information of patients were collected from the center for tuberculosis (TB) prevention and control or TB hospitals in Beijing municipality and nine provinces or autonomous regions in China. Drug resistance testing was conducted on all the isolates to the four first-line anti-TB drugs (isoniazid, rifampicin, streptomycin, and ethambutol). A total of 585 strains were found to be resistant to at least one of the four anti-TB drugs. The Beijing family strains consisted of 499 (53.20%) drug-sensitive strains and 439 (46.80%) drug-resistant strains, whereas the non-Beijing family strains comprised 202 (58.05%) drug-sensitive strains and 146 (41.95%) drug-resistant strains. No significant difference was observed in prevalence (χ= 2.41, P > 0.05) between the drug-resistant and drugsensitive strains among the Beijing family strains. Analysis of monoresistance, multidrug-resistant TB, and geographic distribution of drug resistance did not find any relationships between the M. tuberculosis Beijing genotype and drug-resistance phenotype in China. Results confirmed that the Beijing genotype, the predominant M. tuberculosis genotype in China, was not associated with drug resistance.
Antitubercular Agents ; therapeutic use ; China ; epidemiology ; Drug Resistance, Multiple, Bacterial ; Genetic Variation ; Genotype ; Humans ; Microbial Sensitivity Tests ; Mycobacterium tuberculosis ; genetics ; isolation & purification ; Phenotype ; Tuberculosis, Multidrug-Resistant ; drug therapy ; epidemiology