Analysis of the Utility of MPT64, Drug Susceptibility Testing and Tuberculosis/Nontuberculous Mycobacteria Reverse Transcription Polymerase Chain Reaction for Tuberculosis Diagnosis and Efficiency Compared with Traditional Culture

Abstract

Defining the molecular mechanisms underlying the dormant state of Mycobacterium tuberculosis (MTB) is essential for developing more effective treatments for tuberculosis (TB) infection. We investigated the positivity and resistance rates of TB tests on 6,174 samples referred to a single hospital. Of these, 342 cases (5.5%) were confirmed as positive by acid-fast bacilli staining, 243 cases (71.1%) were detected as MTB cultured on Mycobacterium growth indicator tube medium and 3% Ogawa solid medium, and 341 cases (99.7%) and 234 cases (68.4%) were cultured on either Mycobacterium Growth Indicator Tube or 3% Ogawa solid medium, respectively. For the 341 samples detected as positive in both media, an antigen MPT64 rapid test was performed, confirming TB in 333 cases (97.7%), and 279 cases (81.8%) were analyzed using TB/nontuberculous mycobacteria real-time reverse transcription polymerase chain reaction (RT-PCR). Among the 145 cases confirmed as TB, drug-susceptibility tests showed resistance rates of 23 (15.9%) to isoniazid, 11 (7.6%) to rifampicin, 10 (6.9%) to ethambutol and 10 (6.9%) to rifabutin. Liquid culture testing, despite its longer duration, yielded more accurate results than the relatively rapid RT-PCR. A combination of traditional culture, MPT64, and RT-PCR tests used for infection confirmation was the most efficient method in increasing the TB confirmation rate. This information may aid in developing more precise diagnostic methods for TB.