Speeding up the diagnosis of multidrug-resistant tuberculosis in a high-burden region with the use of a commercial line probe assay

• Published in: Jornal brasileiro de pneumologia 2019, Vol.45 (2), p.e20180128-e20180128
• Main Authors: Brandao, Angela Pires, Pinhata, Juliana Maira Watanabe, Oliveira, Rosangela Siqueira, Galesi, Vera Maria Neder, Caiaffa-Filho, Helio Hehl, Ferrazoli, Lucilaine
• Format: Article
• Language: English
• Subjects: Mycobacterium tuberculosis; Original; RESPIRATORY SYSTEM; Testes de sensibilidade microbiana; Tuberculose resistente a múltiplos medicamentos; Técnicas de diagnóstico molecular
• ISSN: 1806-3713; 1806-3756; 1806-3756
• DOI: 10.1590/1806-3713/e20180128

To evaluate the rapid diagnosis of multidrug-resistant tuberculosis, by using a commercial line probe assay for rifampicin and isoniazid detection (LPA-plus), in the routine workflow of a tuberculosis reference laboratory. The LPA-plus was prospectively evaluated on 341 isolates concurrently submitted to the automated liquid drug susceptibility testing system. Among 303 phenotypically valid results, none was genotypically rifampicin false-susceptible (13/13; 100% sensitivity). Two rifampicin-susceptible isolates harboured rpoB mutations (288/290; 99.3% specificity) which, however, were non-resistance-conferring mutations. LPA-plus missed three isoniazid-resistant isolates (23/26; 88.5% sensitivity) and detected all isoniazid-susceptible isolates (277/277; 100% specificity). Among the 38 (11%) invalid phenotypic results, LPA-plus identified 31 rifampicin- and isoniazid-susceptible isolates, one isoniazid-resistant and six as non-Mycobacterium tuberculosis complex. LPA-plus showed excellent agreement (≥91%) and accuracy (≥99%). Implementing LPA-plus in our setting can speed up the diagnosis of multidrug-resistant tuberculosis, yield a significantly higher number of valid results than phenotypic drug susceptibility testing and provide further information on the drug-resistance level.