Background Reliance on sputum-based testing is a key barrier to increasing access to molecular diagnostics for tuberculosis (TB). Many people with TB are unable to produce sputum, and sputum processing increases the complexity and cost of molecular assays. Tongue swabs are emerging as an alternative to sputum, but performance limits are uncertain. Methods From June 2022 to July 2023, we enrolled 397 consecutive adults with cough >2 weeks at two health centers in Kampala, Uganda. We collected routine demographic and clinical information, sputum for routine TB testing (Xpert MTB/RIF Ultra® and two liquid cultures), and up to four tongue swabs for same-day qPCR. We evaluated tongue swab qPCR diagnostic accuracy in reference to sputum TB test results, quantified TB targets per swab, assessed the impact of serial swabbing, and compared two swab types (Copan FLOQSWAB® and Steripack® spun polyester). Results Among 397 participants, 43.1% were female, median age was 33 years, 23.5% were living with HIV (PLHIV) and 32.0% had confirmed TB. Sputum Xpert Ultra and tongue swab qPCR results were concordant for 98.2% [96.2-99.1] of participants. Tongue swab qPCR sensitivity was 92.6% [95%CI: 86.5, 96.0] and specificity 99.1% [96.9-99.8] vs. microbiological reference standard (MRS). A single tongue swab recovered a seven-log range of TB copies, with a decreasing recovery trend among four serial swabs. We found no difference between swab types. Conclusions Tongue swabs are a promising alternative to sputum for molecular diagnosis of TB, with sensitivity approaching sputum-based molecular tests. Our results provide valuable insights for developing successful tongue swab-based TB diagnostics.

中文翻译：

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在乌干达收集和处理的舌拭子上验证的新型手动 qPCR 检测显示出可与基于痰的分子结核诊断相媲美的灵敏度

背景 对痰检测的依赖是增加结核病 (TB) 分子诊断的主要障碍。许多结核病患者无法产生痰液，而痰液处理增加了分子检测的复杂性和成本。舌拭子正在成为痰液的替代品，但其性能限制尚不确定。方法 从 2022 年 6 月至 2023 年 7 月，我们在乌干达坎帕拉的两个卫生中心连续招募了 397 名咳嗽超过 2 周的成年人。我们收集了常规人口统计和临床信息、用于常规结核病检测的痰液（Xpert MTB/RIF Ultra® 和两种液体培养物），以及最多四个舌拭子用于当天 qPCR。我们根据痰结核病检测结果评估了舌拭子 qPCR 诊断准确性，量化了每个拭子的结核病目标，评估了连续拭子的影响，并比较了两种拭子类型（Copan FLOQSWAB® 和 Steripack® 聚酯纤维）。结果 397 名参与者中，43.1% 为女性，中位年龄为 33 岁，23.5% 为艾滋病毒感染者 (PLHIV)，32.0% 确诊为结核病。 98.2% [96.2-99.1] 的参与者的 Sputum Xpert Ultra 和舌拭子 qPCR 结果一致。与微生物参考标准 (MRS) 相比，舌拭子 qPCR 灵敏度为 92.6% [95%CI: 86.5, 96.0]，特异性为 99.1% [96.9-99.8]。单个舌拭子回收了 7 个对数范围的 TB 副本，四个连续拭子的回收率呈下降趋势。我们发现拭子类型之间没有差异。结论 舌拭子是结核病分子诊断中痰液的一种有前途的替代品，其敏感性接近基于痰的分子检测。我们的结果为开发成功的基于舌拭子的结核病诊断提供了宝贵的见解。