Mycobacterium tuberculosis - XPERT XDR Validation Pakistan
BackgroundThe insurgence of resistance to key drugs of the newly recommended BPaLM regimen is a major reason of concern. In settings with widespread resistance to fluoroquinolones, as Pakistan, new technologies, as the Xpert MTB/XDR, may ensure the upfront screening of drug resistance.This study aims to assess the performance of Xpert MTB/XDR in detecting fluoroquinolones and isoniazid resistance and to propose a renewed diagnostic algorithm for drug resistant tuberculosis (DR-TB).MethodsThis cross-sectional prospective study was approved by the local ethical committee. Samples were programmatically collected from people newly and previously diagnosed with TB over a six-month period. Xpert MTB/RIF Ultra, Xpert MTB/XDR, Genotype MTBDRplus, Genotype MTBDRsl, culture and phenotypic drug susceptibility testing (pDST) for relevant drugs (including bedaquiline and levofloxacin) were performed. Next generation sequencing (NGS) was performed on samples with discordant DST/Xpert MTB/XDR results.ResultsThe analysis demonstrated that Xpert MTB/XDR has a sensitivity of 91.5% and 88.2% respectively and a specificity of 99.5% and 97.7% in detecting isoniazid and fluoroquinolones resistance. NGS was used to solve the discordances identified between Xpert MTB/XDR and pDST results.ConclusionsThe obtained results allowed to design the proposed diagnostic algorithm for the rapid identification of DR-TB, which aims to ensure rapid and equitable access to DST for TB, ultimately improving TB care and control