Sequence analysis for detection of first-line drug resistance in Mycobacterium tuberculosis strains from a high-incidence setting

BMC Microbiology

Research Article

Barbara Oberhauser¹  Foday Dafae²  Silke Feuerriegel³  Stefan Niemann³  Abu Garawani George⁴  Sabine Rüsch-Gerdes⁵  Elvira Richter⁵ 

[1] German Leprosy and TB Relief Association, Würzburg, Germany;Manager of the National Leprosy and Tuberculosis Programme (NLTP), Ministry of Health and Sanitation, Freetown, Sierra Leone;Molecular Mycobacteriology, Research Center Borstel, Borstel, Germany;National Leprosy/TB Reference Laboratory, Freetown, Sierra Leone;National Reference Center for Mycobacteria, Research Center Borstel, Borstel, Germany;

关键词: Resistant Strain;    Drug Susceptibility Testing;    Beijing Genotype;    Resistance Determine Region;    MTBC Strain;   

DOI  :  10.1186/1471-2180-12-90

 received in 2012-01-11, accepted in 2012-05-30,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundDrug resistance displays a problem for the therapy of Mycobacterium tuberculosis infections. For molecular resistance testing, it is essential to have precise knowledge on genomic variations involved in resistance development. However, data from high-incidence settings are only sparely available. Therefore we performed a systematic approach and analyzed a total of 97 M. tuberculosis strains from previously treated patients in Sierra Leone for mutations in katG, rpoB, rrs, rpsL, gidB, embB, pncA and where applicable in inhA and ahpC. Of the strains investigated 50 were either mono- or poly-resistant to isoniazid, rifampin, streptomycin, ethambutol and pyrazinamide or MDR and 47 fully susceptible strains served as controls.ResultsThe majority of isoniazid and rifampin resistant strains had mutations in katG315 (71.9%) and rpoB531 (50%). However, rpoB mutations in codons 511, 516 and 533 were also detected in five rifampin susceptible strains. MIC determinations revealed low-level rifampin resistance for those strains. Thus, the sensitivity and specificity of sequencing of katG for detection of drug resistance were 86.7% and 100% and for sequencing of rpoB 100% and 93.8%, respectively.Strikingly, none of the streptomycin resistant strains had mutations in rrs, but 47.5% harboured mutations in rpsL. Further changes were detected in gidB. Among ethambutol resistant strains 46.7% had mutations at embB306. Pyrazinamide resistant strains displayed a variety of mutations throughout pncA. The specificities of sequencing of rpsL, embB and pncA for resistance detection were high (96-100%), whereas sensitivities were lower (48.8%, 73.3%, 70%).ConclusionsOur study reveals a good correlation between data from molecular and phenotypic resistance testing in this high-incidence setting. However, the fact that particular mutations in rpoB are not linked to high-level resistance is challenging and demonstrates that careful interpretation of molecular resistance assays is mandatory. In addition, certain variations, especially in gidB, appear to be phylogenetically informative polymorphisms rather than markers for drug resistance.

【 授权许可】

CC BY   
© Feuerriegel et al.; licensee BioMed Central Ltd. 2012