Isoniazid killing of mycobacterium smegmatis NADH pyrophosphatase mutant at single-cell level using microfluidics and time-lapse microscopy

Official URL: http://dx.doi.org/10.1038/s41598-017-11503-7

We introduce single-cell analysis for isoniazid-treated Mycobacterium smegmatis mutant, msm1946-NADH pyrophosphatase, using microfluidics and automated time-lapse microscopy. Mycobacterial NADH pyrophosphatase isoforms play an important role for the mechanism of isoniazid and ethionamide activation. Our single-cell analysis revealed important insights on isoniazid killing mechanism that was masked by traditional killing assays, raised significant questions related to viable but non-culturable subpopulation of cells, and existing methods that defines minimum inhibitory concentration of drugs. The major goal of this study was quantitatively analyze bacterial cell parameters to obtain high-resolution data for the time evolution of antibiotic killing at the single-cell level. The presented tools and methods could be applied to the closely related organisms to provide more detailed information for the design and employment of antibiotic treatments.