While some healthcare systems have shifted to molecular diagnostics, culture still remains the gold standard for tuberculosis diagnosis, but it is limited by its long duration to a positive result. Methods to reduce time to culture positivity (TTP) are urgently required. We determined if growth factor supplementation in the mycobacterial growth indicator tube (MGIT) culture system reduces TTP. MGITs were supplemented with fresh culture filtrate (CF) as a source of growth stimulatory molecules from axenic Mycobacterium tuberculosis culture. Different volumes of CF and media components were tested. The performance of these modified MGITs was assessed with sputum from HIV-TB co-infected individuals. Reducing the volume of MGIT cultures and removal of detergent from cultures grown to generate CF had a marginal but significant benefit on reducing TTP. In a subset of specimens, CF inhibited growth. Following optimization of methods, a reduced TTP occurred in specimens with low bacillary load as measured by GeneXpert, smear microscopy and colony forming units. Three specimens that were negative under standard conditions flagged positive following CF supplementation. Our data provide preliminary evidence that addition of CF to MGIT cultures can enhance detection of M. tuberculosis in HIV-TB co-infected patients with low sputum bacillary loads.

虽然一些医疗保健系统已转向分子诊断，但培养仍然是结核病诊断的金标准，但由于其持续时间长而无法获得阳性结果，因此受到限制。迫切需要缩短培养阳性时间 (TTP) 的方法。我们确定了在分枝杆菌生长指示管 (MGIT) 培养系统中补充生长因子是否会降低 TTP。MGITs 补充有新鲜培养滤液 (CF) 作为来自无菌结核分枝杆菌的生长刺激分子来源文化。测试了不同体积的 CF 和媒体组件。这些改良的 MGITs 的性能是用 HIV-TB 合并感染者的痰液评估的。减少 MGIT 培养物的体积和从培养产生 CF 的培养物中去除去污剂对降低 TTP 有边际但显着的好处。在样本的一个子集中，CF 抑制了生长。在优化方法后，通过 GeneXpert、涂片显微镜和菌落形成单元测量的低细菌载量标本中 TTP 降低。在标准条件下为阴性的三个样本在补充 CF 后标记为阳性。我们的数据提供了初步证据，表明在 MGIT 培养物中添加 CF 可以增强对低痰菌负荷的 HIV-TB 合并感染患者的结核分枝杆菌检测。