Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil.
Infect Control Hosp Epidemiol. 2020 Jul;41(7):784-788. doi: 10.1017/ice.2020.96. Epub 2020 Apr 17.
Tuberculosis (TB) transmission in healthcare facilities is still a concern in low-income countries, where airborne isolation rooms are scarce due to high costs. We evaluated the use of single GeneXpert MTB/RIF, the molecular Mycobacterium tuberculosis (MTB) DNA and resistance to rifampicin (RIF) test, as an accurate and faster alternative to the current criteria of 3 negative acid-fast bacilli (AFB) smears to remove patients from airborne isolation.
In this real-world investigation, we evaluated the impact of a single GeneXpert MTB/RIF on the decision making for discharging patients from respiratory isolation. We enrolled patients with suspected pulmonary TB in a public hospital that provides care for high-complexity patients in Brazil. We studied the performance, costs, and time saved comparing the GeneXpert MTB/RIF with AFB smears.
We enrolled 644 patients in 3 groups based on the number of AFB smears performed (1, 2, and 3, respectively) on respiratory specimens. GeneXpert MTB/RIF demonstrated good performance compared to AFB smear to rule out TB in all groups. The negative predictive value for AFB smear was 94% (95% confidence interval [CI], 0.90-0.97) and 98% (95% CIs, 0.94-0.99) for GeneXpert MTB/RIF in G3. The isolation discharge based on 3 AFB smears took 84 hours compared to 24 hours with GeneXpert MTB/RIF, which represents 560 patient-days saved in the isolation rooms.
A single GeneXpert MTB/RIF is a fast and strong predictor for TB absence in a high-complexity hospital, which is quite similar to results obtained in recent studies in low-burden settings. This molecular test may also increase patient rotation through isolation rooms, with a positive impact in the emergency room and infectious diseases wards.
在低收入国家，由于成本高昂，医疗机构中结核病（TB）的传播仍然令人担忧，那里缺乏空气传播隔离室。我们评估了单 GeneXpert MTB/RIF（分子结核分枝杆菌（MTB）DNA 和对利福平（RIF）的耐药性检测）的使用，作为一种替代目前 3 次阴性抗酸杆菌（AFB）涂片以将患者从空气传播隔离中移除的准确且更快的方法。
在这项真实世界的研究中，我们评估了单次 GeneXpert MTB/RIF 对决定患者是否从呼吸隔离中出院的影响。我们招募了巴西一家为高复杂度患者提供服务的公立医院中疑似肺结核的患者。我们研究了 GeneXpert MTB/RIF 与 AFB 涂片相比在性能、成本和节省时间方面的表现。
我们根据呼吸道标本上进行的 AFB 涂片数量（分别为 1、2 和 3）将 644 名患者分为 3 组。与 AFB 涂片相比，GeneXpert MTB/RIF 在所有组中都表现出良好的性能，可排除 TB。在 G3 中，AFB 涂片的阴性预测值为 94%（95%置信区间[CI]，0.90-0.97），GeneXpert MTB/RIF 为 98%（95%CI，0.94-0.99）。基于 3 次 AFB 涂片的隔离出院需要 84 小时，而使用 GeneXpert MTB/RIF 则需要 24 小时，这意味着隔离病房可节省 560 个患者日。
在高复杂度医院中，单次 GeneXpert MTB/RIF 是一种快速且强有力的 TB 阴性预测指标，与低负担环境中的近期研究结果非常相似。这种分子检测还可以增加患者在隔离病房中的周转率，对急诊室和传染病病房产生积极影响。
