Nathavitharana Ruvandhi R, Pearl Abarna, Biewer Amanda, Tzelios Christie, Mase Sundari, Munsiff Sonal S, Nardell Edward
Division of Infectious Diseases, Beth Israel Deaconess Medical Center and Harvard Medical School.
Department of Medicine, Harvard Medical School, Boston, Massachusetts.
J Infect Dis. 2025 Feb 4;231(1):10-22. doi: 10.1093/infdis/jiae482.
Determining the extent and duration of infectiousness of people with pulmonary tuberculosis (PWPTB) is critical for various aspects of tuberculosis care, including decisions regarding isolation. Studies suggest considerable heterogeneity in infectiousness of PWPTB. Pretreatment, measures of bacillary burden, including sputum smear microscopy, culture time to positivity, and Xpert MTB/RIF cycle threshold (Ct) value, predict the risk of transmission to contacts. Index patients with smear-negative disease pose lower infectious risk than those who have smear-positive disease, and household contact infection is more likely with index patients who have lower Xpert Ct values. Newer tools that enable detection of Mycobacterium tuberculosis complex from cough aerosol sampling and face mask sampling may be better predictors of contact infection risk. Clinical factors such as cough strength and frequency, and presence of cavitation on chest imaging, may also assist with risk prediction. Posttreatment, smear and culture status are poor predictors of infectiousness. While the exact duration of infectiousness post-treatment initiation remains uncertain, data from human-to-guinea pig transmission studies and clinical studies suggest that effective treatment results in a rapid decline in infectiousness, irrespective of smear or culture conversion. This is largely supported by early bactericidal activity and transcriptomic studies, as well as cough aerosol sampling studies, although a subset of patients may have persistent cough aerosol positivity. These findings can enable a more nuanced approach to isolation decision making while further research studies are awaited.
确定肺结核患者（PWPTB）的传染性程度和持续时间对于结核病治疗的各个方面都至关重要，包括隔离决策。研究表明，PWPTB的传染性存在很大差异。治疗前，细菌负荷的测量指标，包括痰涂片显微镜检查、培养阳性时间以及Xpert MTB/RIF循环阈值（Ct）值，可预测传播给接触者的风险。涂片阴性疾病的索引患者比涂片阳性疾病的患者传染性风险更低，且Xpert Ct值较低的索引患者更易导致家庭接触感染。能够从咳嗽气溶胶采样和口罩采样中检测结核分枝杆菌复合群的新工具可能是接触感染风险的更好预测指标。咳嗽强度和频率以及胸部影像学上有无空洞等临床因素也可能有助于风险预测。治疗后，涂片和培养状态对传染性的预测能力较差。虽然治疗开始后传染性的确切持续时间仍不确定，但人与豚鼠传播研究和临床研究的数据表明，有效的治疗会使传染性迅速下降，无论涂片或培养是否转阴。早期杀菌活性、转录组学研究以及咳嗽气溶胶采样研究在很大程度上支持了这一点，尽管有一部分患者可能持续存在咳嗽气溶胶阳性。在等待进一步研究的同时，这些发现可以使隔离决策采用更细致入微的方法。
