In:
Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 59, No. 2 ( 2015-02), p. 818-825
Abstract:
The emergence and transmission of extensively drug-resistant tuberculosis (XDR-TB) pose an increasing threat to global TB control. This study aimed to identify the patterns of evolution and transmission dynamics of XDR-TB in populations in a region of China where TB is highly endemic. We analyzed a total of 95 XDR-TB isolates collected from 2003 to 2009 in Chongqing, China. Eight drug resistance genes covering 7 drugs that define XDR-TB were amplified by PCR followed by DNA sequencing. Variable-number tandem repeat 16-locus (VNTR-16) genotyping and genotypic drug resistance profiles were used to determine the evolution or transmission patterns of XDR-TB strains. Our results indicated that the Beijing genotype was predominant (85/95 [89.5%]) in XDR-TB strains, and as many as 40.0% (38/95) of the isolates were distributed into 6 clusters based on VNTR-16 genotyping and drug resistance mutation profiles. All isolates of each cluster harbored as many as six identical resistance mutations in the drug resistance genes rpoB , katG , inhA promoter, embB , rpsL , and gidB . Among the nine cases with continuous isolates from multidrug-resistant (MDR) to XDR-TB, 4 cases represented acquired drug resistance, 4 cases were caused by transmission, and 1 case was due to exogenous superinfection. The XDR-TB epidemic in China is mainly caused by a high degree of clonal transmission, but evolution from MDR to XDR and even superinfection with a new XDR strain can also occur.
Type of Medium:
Online Resource
ISSN:
0066-4804
,
1098-6596
DOI:
10.1128/AAC.03504-14
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2015
detail.hit.zdb_id:
1496156-8
SSG:
12
SSG:
15,3
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