Rapid Sputum Multiplex Detection of the M. tuberculosis Complex (MTBC) and Resistance Mutations for Eight Antibiotics by Nucleotide MALDI-TOF MS

Abstract

The increasing incidence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis (MTB) adds further urgency for rapid and multiplex molecular testing to identify the MTB complex and drug susceptibility directly from sputum for disease control. A nucleotide matrix-assisted-laser-desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based assay was developed to identify MTB (MTBID panel) and 45 chromosomal mutations for resistance to eight antibiotics (MTBDR panel). We conducted a 300 case trial from outpatients to evaluate this platform. An MTBID panel specifically identified MTB with as few as 10 chromosome DNA copies. The panel was 100% consistent with an acid-fast stain and culture for MTB, nontuberculous mycobacteria, and non-mycobacteria bacteria. The MTBDR panel was validated using 20 known MDR-MTB isolates. In a 64-case double-blind clinical isolates test, the sensitivity and specificity were 83% and 100%, respectively. In a 300-case raw sputum trial, the MTB identification sensitivity in smear-negative cases using MALDI-TOF MS was better than the COBAS assay (61.9% vs. 46.6%). Importantly, the failure rate of MALDI-TOF MS was better than COBAS (11.3% vs. 26.3%). To the best of our knowledge, the test described herein is the only multiplex test that predicts resistance for up to eight antibiotics with both sensitivity and flexibility.

Profiles of volatile indole emitted by Escherichia coli based on CDI-MS

“…Secondary electrospray ionization-MS (SESI-MS), with the ability to directly sample gas, exhibits some of the best features of a desired laboratory analytical tool 7 . MALDI-TOF MS has been widely accepted and gradually applied in clinical laboratories and is based on the differences of bacterial protein spectra 8,9 . These three different methods exhibit their own shortcomings 10 .…”

Revisiting the methods for detecting Mycobacterium tuberculosis: what has the new millennium brought thus far?

“…However, this technique struggles to differentiate mycobacterial species with high genetic similarity [ 139 ]. In any case, MALDI-TOF MS is considered to be a promising diagnostic method that potentially accelerates the identification of slow-growing mycobacterial species and might also identify drug-resistant M. tuberculosis strains [ 140 ]. Besides the above-mentioned advantages, the drawback of MS for wide use in TB diagnosis is its high cost, especially when it is implemented in LMI countries.…”

Use of MALDI-TOF mass spectrometry in the battle against bacterial infectious diseases: recent achievements and future perspectives

“…Based on this so called MTBID panel, resistance to eight antibiotics caused by 45 chromosomal mutations was studied. Although this platform cannot allow de novo mutation identification, the introduction of specific probes in the spectrum may be the solution [14].…”