Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, LE1 9HN UK.
Am J Respir Crit Care Med. 2010 Jan 15;181(2):174-80. doi: 10.1164/rccm.200905-0661OC. Epub 2009 Oct 29.
Resuscitation-promoting factors (Rpfs) are a family of secreted proteins produced by Mycobacterium tuberculosis (Mtb) that stimulate mycobacterial growth. Although mouse infection studies show that they support bacterial survival and disease reactivation, it is currently unknown whether Rpfs influence human infection. We hypothesized that tuberculous sputum might include a population of Rpf-dependent Mtb cells.
To determine whether Rpf-dependent Mtb cells are present in human sputum and explore the impact of chemotherapy on this population.
In tuberculous sputum samples we compared the number of cells detected by conventional agar colony-forming assay with that determined by limiting dilution, most-probable number assay in the presence or absence of Rpf preparations.
In 20 of 25 prechemotherapy samples from separate patients, 80-99.99% of the cells demonstrated by cultivation could be detected only with Rpf stimulation. Mtb cells with this phenotype were not generated on specimen storage or by inoculating sputum samples with a selection of clinical isolates; moreover, Rpf dependency was lost after primary isolation. During chemotherapy, the proportion of Rpf-dependent cells was found to increase relative to the surviving colony-forming population.
Smear-positive sputum samples are dominated by a population of Mtb cells that can be grown only in the presence of Rpfs. These intriguing proteins are therefore relevant to human infection. The Rpf-dependent population is invisible to conventional culture and is progressively enhanced in relative terms during chemotherapy, indicating a form of phenotypic resistance that may be significant for both chemotherapy and transmission.
复苏促进因子（Rpfs）是分枝杆菌属（Mycobacterium tuberculosis，Mtb）分泌的一组蛋白，可刺激分枝杆菌生长。虽然小鼠感染研究表明它们支持细菌存活和疾病再激活，但目前尚不清楚 Rpfs 是否会影响人类感染。我们假设结核痰中可能包含一组依赖 Rpfs 的 Mtb 细胞。
确定人类痰液中是否存在依赖 Rpf 的 Mtb 细胞，并探讨化疗对此人群的影响。
在结核痰样本中，我们通过常规琼脂集落形成试验与有限稀释法（存在或不存在 Rpf 制剂时的最可能数测定法）比较了培养物中检测到的细胞数量。
在 25 名单独患者的 20 份化疗前样本中，培养检测到的 80%-99.99%的细胞仅在 Rpf 刺激下才能被检测到。这种表型的 Mtb 细胞不会在标本储存时产生，也不会通过接种一系列临床分离株来接种痰液样本；此外，Rpf 依赖性在初次分离后丢失。在化疗期间，发现依赖 Rpf 的细胞比例相对于存活的集落形成细胞群增加。
涂阳痰液样本主要由 Mtb 细胞群主导，只有在 Rpfs 存在的情况下才能生长。这些引人入胜的蛋白与人类感染有关。依赖 Rpf 的群体对常规培养是不可见的，并且在化疗过程中相对而言逐渐增强，这表明了一种表型耐药性，这可能对化疗和传播都很重要。
