Dan Zhang1, Jun An2, Yufeng Wang3, Yu Pang4. 1. Yongchuan Hospital, Chongqing Medical University, Chongqing, China; National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Road, Changping District, Beijing, 102206, China. 2. Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, Beijing, China. 3. National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Road, Changping District, Beijing, 102206, China. 4. National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Road, Changping District, Beijing, 102206, China. Electronic address: pangyu@chinatb.org.
Abstract
OBJECTIVES: To gain an insight into the genetic diversity of multidrug-resistant (MDR) Mycobacterium tuberculosis isolates in Chongqing Municipality, an MDR tuberculosis (MDR-TB) epidemic region of China. METHODS: In this study, a total of 208M. tuberculosis isolates from smear-positive TB patients in Chongqing were genotyped by spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat typing (MIRU-VNTR). In addition, statistical analysis was performed to evaluate the distributions of drug susceptibility patterns and demographic data among different genotypes. RESULTS: Our results showed that 156 MDR M. tuberculosis strains (75.0%) belonged to the Beijing genotype, while the other 52 strains (25.0%) were non-Beijing genotype. The proportion of Beijing genotype in the re-treated patient group was significantly higher than that in the new patient group (p=0.013), while drug resistance and demographic characteristics showed no statistically significant associations with Beijing genotype (p>0.05). In addition, the 208 strains were clustered into 193 genotypes using a 10-locus VNTR set; the cumulative clustering rate was 12.98% and the HGDI was 0.9991. CONCLUSIONS: Beijing genotype was the predominant genotype among the isolates from MDR-TB cases in Chongqing. The re-treated MDR-TB cases were more likely to be attributed to Beijing genotype infection. The 10-locus VNTR set demonstrated a good discrimination power for genotyping MDR M. tuberculosis isolates circulating in Chongqing Municipality.
OBJECTIVES: To gain an insight into the genetic diversity of multidrug-resistant (MDR) Mycobacterium tuberculosis isolates in Chongqing Municipality, an MDR tuberculosis (MDR-TB) epidemic region of China. METHODS: In this study, a total of 208M. tuberculosis isolates from smear-positive TB patients in Chongqing were genotyped by spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat typing (MIRU-VNTR). In addition, statistical analysis was performed to evaluate the distributions of drug susceptibility patterns and demographic data among different genotypes. RESULTS: Our results showed that 156 MDR M. tuberculosis strains (75.0%) belonged to the Beijing genotype, while the other 52 strains (25.0%) were non-Beijing genotype. The proportion of Beijing genotype in the re-treated patient group was significantly higher than that in the new patient group (p=0.013), while drug resistance and demographic characteristics showed no statistically significant associations with Beijing genotype (p>0.05). In addition, the 208 strains were clustered into 193 genotypes using a 10-locus VNTR set; the cumulative clustering rate was 12.98% and the HGDI was 0.9991. CONCLUSIONS: Beijing genotype was the predominant genotype among the isolates from MDR-TB cases in Chongqing. The re-treated MDR-TB cases were more likely to be attributed to Beijing genotype infection. The 10-locus VNTR set demonstrated a good discrimination power for genotyping MDR M. tuberculosis isolates circulating in Chongqing Municipality.