Evaluation of colorimetric methods using nicotinamide for rapid detection of pyrazinamide resistance in Mycobacterium tuberculosis

NC Mirabal, SL Yzquierdo, D Lemus, M Madruga, Y Milián, M Echemendía, H Takiff, A Martin, P Van der Stuyft, JC Palomino, E Montoro

    Research output: Contribution to journalA1: Web of Science-article

    Abstract

    The direct detection of pyrazinamide resistance in Mycobacterium tuberculosis is sufficiently difficult so that many laboratories don't attempt it. Most pyrazinamide resistance is caused by mutations that inactivate the pyrazinamidase enzyme needed to convert the prodrug pyrazinamide to its active form. We evaluated two newer and simpler methods to assess pyrazinamidase activity - the nitrate reductase and malachite green microtube assays - using nicotinamide in place of pyrazinamide. A total of 102 strains were tested by these methods and the results compared with those obtained by the classic Wayne assay. Mutations in the pncA gene were identified by sequencing the pncA gene from all isolates in which pyrazinamide-resistance was detected by any of the three methods. Both the nitrate reductase and malachite green microtube assays showed sensitivities of 93.75% and specificities of 97.67%. Mutations in the pncA gene were found in 14 of 16 strains that were pyrazinamide resistant, and in 1 of 4 strains that were sensitive by the Wayne assay. Both of these simple methods, used with nicotinamide, are promising and inexpensive alternatives for the rapid detection of pyrazinamide resistance in limited-resource countries
    Original languageEnglish
    JournalJournal of Clinical Microbiology
    Volume48
    Issue number8
    Pages (from-to)2729-2733
    Number of pages5
    ISSN0095-1137
    DOIs
    Publication statusPublished - 2010

    Keywords

    • B780-tropical-medicine
    • Bacterial diseases
    • Tuberculosis
    • Mycobacterium tuberculosis
    • Rapid diagnostic tests
    • Nicotinamide
    • Drug resistance
    • Pyrazinamide
    • Colorimetric methods
    • Evaluation
    • Strains
    • Mutations
    • Sensitivity
    • Specificity

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