Acuña-Villaorduña Carlos, Ayakaka Irene, Schmidt-Castellani Luiz Guilherme, Mumbowa Francis, Marques-Rodrigues Patricia, Gaeddert Mary, White Laura F, Palaci Moises, Ellner Jerrold J, Dietze Reynaldo, Joloba Moses, Fennelly Kevin P, Jones-López Edward C
Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine and Boston Medical Center, Massachusetts.
Lemuel Shattuck Hospital, Boston University School of Public Health, Massachusetts.
Open Forum Infect Dis. 2019 Apr 11;6(6):ofz184. doi: 10.1093/ofid/ofz184. eCollection 2019 Jun.
Epidemiologic data suggests that only a minority of tuberculosis (TB) patients are infectious. Cough aerosol sampling is a novel quantitative method to measure TB infectiousness.
We analyzed data from three studies conducted in Uganda and Brazil over a 13-year period. We included sputum acid fast bacilli (AFB) and culture positive pulmonary TB patients and used a cough aerosol sampling system (CASS) to measure the number of colony-forming units (CFU) of Mycobacterium tuberculosis in cough-generated aerosols as a measure for infectiousness. Aerosol data was categorized as: aerosol negative (CFU = 0) and aerosol positive (CFU > 0). Logistic regression models were built to identify factors associated with aerosol positivity.
M. tuberculosis was isolated by culture from cough aerosols in 100/233 (43%) TB patients. In an unadjusted analysis, aerosol positivity was associated with fewer days of antituberculous therapy before CASS sampling ( = .0001), higher sputum AFB smear grade ( = .01), shorter days to positivity in liquid culture media ( = .02), and larger sputum volume ( = .03). In an adjusted analysis, only fewer days of TB treatment (OR 1.47 per 1 day of therapy, 95% CI 1.16-1.89; = .001) was associated with aerosol positivity.
Cough generated aerosols containing viable M. tuberculosis, the infectious moiety in TB, are detected in a minority of TB patients and rapidly become non-culturable after initiation of antituberculous treatment. Mechanistic studies are needed to further elucidate these findings.
流行病学数据表明，只有少数结核病（TB）患者具有传染性。咳嗽气溶胶采样是一种测量结核病传染性的新型定量方法。
我们分析了在13年期间于乌干达和巴西开展的三项研究的数据。我们纳入了痰涂片抗酸杆菌（AFB）阳性且培养阳性的肺结核患者，并使用咳嗽气溶胶采样系统（CASS）来测量咳嗽产生的气溶胶中结核分枝杆菌的菌落形成单位（CFU）数量，以此作为传染性的衡量指标。气溶胶数据被分类为：气溶胶阴性（CFU = 0）和气溶胶阳性（CFU > 0）。构建逻辑回归模型以确定与气溶胶阳性相关的因素。
在233例结核病患者中，通过培养从咳嗽气溶胶中分离出结核分枝杆菌的有100例（43%）。在未经调整的分析中，气溶胶阳性与CASS采样前抗结核治疗的天数较少（P = .0001）、痰AFB涂片等级较高（P = .01）、液体培养基中阳性天数较短（P = .02）以及痰量较大（P = .03）相关。在调整分析中，只有抗结核治疗天数较少（每治疗1天的OR为1.47，95%CI为1.16 - 1.89；P = .001）与气溶胶阳性相关。
在少数结核病患者中检测到含有结核分枝杆菌活菌（结核病中的感染部分）的咳嗽产生的气溶胶，并且在开始抗结核治疗后迅速变得不可培养。需要进行机制研究以进一步阐明这些发现。
