Mycobacterium tuberculosis Subculture Results in Loss of Potentially Clinically Relevant Heteroresistance.
Multidrug-resistant tuberculosis (TB) presents a major public health dilemma. Heteroresistance, the coexistence of drug-resistant and drug-susceptible strains or of multiple drug-resistant strains with discrete haplotypes, may affect accurate diagnosis and the institution of effective treatment. Subculture, or passage of cells onto fresh growth medium, is utilized to preserve Mycobacterium tuberculosis cell lines and is universally employed in TB diagnostics. The impact of such passages, typically performed in the absence of drug, on drug-resistant subpopulations is hypothesized to vary according to the competitive costs of genotypic resistance-associated variants. We applied ultradeep next-generation sequencing to 61 phenotypically rifampin-monoresistant (n = 17) and preextensively (n = 41) and extensively (n = 3) drug-resistant isolates with presumptive heteroresistance at two time points in serial subculture. We found significant dynamic loss of minor-variant resistant subpopulations across all analyzed resistance-determining regions, including eight isolates (13%) whose antibiogram data would have transitioned from resistant to susceptible for at least one drug through subculture. Surprisingly, some resistance-associated variants appeared to be selected for in subculture.
['Metcalfe|John Z|JZ|', 'Streicher|Elizabeth|E|', 'Theron|Grant|G|', 'Colman|Rebecca E|RE|0000-0002-6854-2100', 'Penaloza|Renee|R|', 'Allender|Christopher|C|', 'Lemmer|Darrin|D|', 'Warren|Robin M|RM|', 'Engelthaler|David M|DM|']
D000995:Antitubercular Agents D001426:Bacterial Proteins D027081:DNA Gyrase D012321:DNA-Directed RNA Polymerases D024901:Drug Resistance, Multiple, Bacterial D024841:Fluoroquinolones D059014:High-Throughput Nucleotide Sequencing D006801:Humans D007538:Isoniazid D009169:Mycobacterium tuberculosis D012293:Rifampin D018088:Tuberculosis, Multidrug-Resistant
heteroresistance drug-resistant tuberculosis gyrA rpoB rrs