Dugdale Caitlin M, Zachary Kimon C, McEvoy Dustin S, Branda John A, Courtney Amy, Craig Rebecca, Doms Alexandra, Germaine Lindsay, Green Chloe V, Gulbas Eren, Hooper David C, Hurtado Rocio M, Hyle Emily P, Jerry Michelle S, Lazarus Jacob E, Paras Molly, Turbett Sarah E, Shenoy Erica S
Medical Practice Evaluation Center, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA.
Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA.
Open Forum Infect Dis. 2024 May 3;11(6):ofae253. doi: 10.1093/ofid/ofae253. eCollection 2024 Jun.
For persons with suspected pulmonary tuberculosis, the guidelines of the Centers for Disease Control and Prevention recommend collecting 3 respiratory specimens 8 to 24 hours apart for acid-fast bacilli (AFB) smear and culture, in addition to 1 nucleic acid amplification test (NAAT). However, data supporting this approach are limited. Our objective was to estimate the performance of 1, 2, or 3 AFB smears with or without NAATs to detect pulmonary tuberculosis in a low-prevalence setting.
We conducted a retrospective study of hospitalized persons at 8 Massachusetts acute care facilities who underwent mycobacterial culture on 1 or more respiratory specimens between July 2016 and December 2022. We evaluated percentage positivity and yield on serial AFB smears and NAATs among people with growth of on mycobacterial cultures.
Among 104 participants with culture-confirmed pulmonary tuberculosis, the first AFB smear was positive in 41 cases (39%). A second AFB smear was positive in 11 (22%) of the 49 cases in which it was performed. No third AFB smears were positive following 2 initial negative smears. Of 52 smear-negative cases, 36 had a NAAT performed, leading to 23 additional diagnoses. Overall sensitivity to detect tuberculosis prior to culture positivity was higher in any strategy involving 1 or 2 NAATs (74%-79%), even without AFB smears, as compared with 3 smears alone (60%).
Tuberculosis diagnostic testing with 2 AFB smears offered the same yield as 3 AFB smears while potentially reducing laboratory burden and duration of airborne infection isolation. Use of 1 or 2 NAATs increased sensitivity to detect culture-positive pulmonary tuberculosis when added to AFB smear-based diagnostic testing alone.
对于疑似肺结核患者，美国疾病控制与预防中心的指南建议，除进行1次核酸扩增检测（NAAT）外，还应每隔8至24小时采集3份呼吸道标本进行抗酸杆菌（AFB）涂片和培养。然而，支持这种方法的数据有限。我们的目的是评估在低发病率环境中，进行1次、2次或3次AFB涂片加或不加NAAT检测肺结核的性能。
我们对2016年7月至2022年12月期间在马萨诸塞州8家急性护理机构住院且接受1份或更多份呼吸道标本分枝杆菌培养的患者进行了一项回顾性研究。我们评估了分枝杆菌培养生长的患者中连续AFB涂片和NAAT的阳性百分比及检出率。
在104例经培养确诊为肺结核的参与者中，首次AFB涂片阳性41例（39%）。在进行第二次AFB涂片的49例患者中，11例（22%）呈阳性。在最初2次涂片阴性后，没有第三次AFB涂片呈阳性。在52例涂片阴性的病例中，36例进行了NAAT检测，又确诊了23例。与仅进行3次涂片（60%）相比，在任何涉及1次或2次NAAT的策略中，即使不进行AFB涂片，在培养阳性前检测肺结核的总体敏感性更高（74%-79%）。
2次AFB涂片进行肺结核诊断检测的检出率与3次AFB涂片相同，同时可能减轻实验室负担并缩短空气传播感染隔离时间。单独在基于AFB涂片的诊断检测中增加1次或2次NAAT检测可提高检测培养阳性肺结核的敏感性。
