Division of Pulmonary and Critical Care Medicine, Zuckerberg San Francisco General Hospital, University of California, San Francisco, San Francisco, California, USA
DST/NRF Centre of Excellence for Biomedical Tuberculosis Research and SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa.
Antimicrob Agents Chemother. 2017 Oct 24;61(11). doi: 10.1128/AAC.00888-17. Print 2017 Nov.
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 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 ( = 17) and preextensively ( = 41) and extensively ( = 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.
耐多药结核病（TB）是一个重大的公共卫生难题。异质性耐药是指耐药株和敏感株共存，或多种耐药株与离散单倍型共存，这可能会影响准确诊断和有效治疗的实施。传代培养，即将细胞接种到新鲜生长培养基中，用于保存细胞系，在结核病诊断中被广泛应用。在没有药物的情况下进行这种传代培养，对耐药亚群的影响，据推测会根据基因型耐药相关变异的竞争成本而有所不同。我们对 61 株表型利福平单耐药（=17）和预广泛耐药（=41）和广泛耐药（=3）、在两个时间点的连续传代中具有疑似异质性耐药的分离株进行了超高深度下一代测序。我们发现所有分析的耐药决定区域中，次要变异耐药亚群都有显著的动态丢失，包括 8 株（13%）的药敏谱数据通过传代培养至少有一个药物从耐药转变为敏感。令人惊讶的是，一些耐药相关变异似乎在传代培养中被选择了出来。
