Clonal variants were subcultured on Mycobacteria Growth Indicator Tubes (BACTEC MGIT 960 System; Becton Dickinson) supplemented with BBL™ PANTA™ and BACTEC MGIT 960 Growth Supplement, as indicated by the manufacturer. Inocula were obtained from positive tubes (3 days) following the protocol used for antimicrobial susceptibility testing. Three MGITs were inoculated after ensuring equivalent bacterial concentrations in the 3 aliquots of inoculum used by plating them on Middlebrook 7H11 agar (Difco). Growth curves were obtained by monitoring the growth units (GU) every hour using BD EpiCenter™. The fitness of the clonal variants was compared based on 2 parameters taken from the growth curves: (i) lag phase (time to a positive threshold [75 GU]) and (ii) rate growth (time required for the 4,000–6,000–GU increase).
The means and standard deviations were determined, and one-way analysis of variance with repeated measures was used to determine P-values, which were adjusted using a Bonferroni correction.
The means and standard deviations were determined, and one-way analysis of variance with repeated measures was used to determine P-values, which were adjusted using a Bonferroni correction.