[Relationship between Beijing genotypes of Mycobacterium tuberculosis and drug-resistant phenotypes].
OBJECTIVE
To investigate the distribution of the Beijing genotypes of Mycobacterium tuberculosis (M. tuberculosis) and the relationships between Beijing genotype strains and drug-resistant phenotypes in China.


METHODS
Clinical isolates were collected during a 9-month research period from April to December in 2008 in six geographic regions of China. One isolate that had been biochemically confirmed to be a member of the M. tuberculosis complex was collected from each patient. The demographic data of the patients (eg. sex, age, and history of tuberculosis) as well as the drug resistance patterns and sources of the clinical isolates were collected. Drug susceptibility testing was performed using proportion method. Beijing genotypes of M. tuberculosis were identified by spacer oligonucleotide typing or insertion of IS6110 in the genomic dnaA-dnaN locus.


RESULTS
Among the 410 M. tuberculosis clinical isolates, 67.1% (275/410) isolates were Beijing genotypes of M. tuberculosis. Significantly larger proportions of tuberculosis patients were infected with Beijing genotypes in the northeastern regions of China than that of in the central-western regions (chi2 = 20.50, P = 0.000). No significant associations were found either between Beijing genotype strains and patients' age, sex, or treatment history. Multidrug-resistant isolates and rifampin-resistant isolates were more common among Beijing genotype strains than among non-Beijing strains (P = 0.002, P = 0.005).


CONCLUSIONS
About two third of the clinical isolates of M. tuberculosis in China are Beijing genotypes. Beijing genotype strains are not correlated with patients' age, sex, treatment history. People living in the northeastern regions of China are more susceptible to Beijing genotypes than those living in the central-western of China. Beijing genotype strains tend to be rifampin-resistant or multidrug-resistant.
Wang
Sheng-Fen
SF
National Tuberculosis Reference Laboratory, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
Zhao
Yan-Lin
YL
Huang
Hai-Rong
HR
Li
Qiang
Q
Zhou
Yang
Y
Ou
Xi-Chao
XC
Fu
Yu-Hong
YH
D000995:Antitubercular Agents / Q000494:pharmacology*; D002681:China; D005838:Genotype; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000235:genetics*; D010641:Phenotype; D012293:Rifampin / Q000494:pharmacology; D014376:Tuberculosis / Q000188:drug therapy; D018088:Tuberculosis, Multidrug-Resistant / Q000235:genetics*
D000995:Antitubercular Agents; D012293:Rifampin