结核分枝杆菌从抗酸杆菌涂片阴性患者中的传播。

Transmission of Mycobacterium tuberculosis from patients smear-negative for acid-fast bacilli.

作者信息

Behr M A, Warren S A, Salamon H, Hopewell P C, Ponce de Leon A, Daley C L, Small P M

机构信息

Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada.

出版信息

Lancet. 1999 Feb 6;353(9151):444-9. doi: 10.1016/s0140-6736(98)03406-0.

DOI:10.1016/s0140-6736(98)03406-0

PMID:9989714

Abstract

BACKGROUND

The microscopic examination of sputum for acid-fast bacilli, is a simple and rapid test that is used to provide a presumptive diagnosis of infectious tuberculosis. While patients with tuberculosis with sputum smears negative for acid-fast bacilli are less infectious than those with positive smears, both theoretical and empirical evidence suggest that they can still transmit Mycobacterium tuberculosis. We aimed to estimate the risk of transmission from smear-negative individuals.

METHODS

As part of an ongoing study of the molecular epidemiology of tuberculosis in San Francisco, patients with tuberculosis with mycobacterial isolates with the same DNA fingerprint were assigned to clusters that were assumed to have involved recent transmission. Secondary cases with tuberculosis, whose mycobacterial isolates had the same DNA, were linked to their presumed source case to estimate transmission from smear-negative patients. Sensitivity analyses were done to assess potential bias due to misclassification of source cases, unidentified source cases, and HIV-1 co-infection.

FINDINGS

1574 patients with culture-positive tuberculosis were reported and DNA fingerprints were available for 1359 (86%) of these patients. Of the 71 clusters of patients infected with strains that had matching fingerprints, 28 (39% [95% CI 28-52]) had a smear-negative putative source. There were 183 secondary cases in these 71 clusters, of whom a minimum of 32 were attributed to infection by smear-negative patients (17% [12-24]). The relative transmission rate of smear-negative compared with smear-positive patients was calculated as 0.22 (95% CI 0.16-0.32). Sensitivity analyses and stratification for HIV-1 status had no impact on these estimates.

INTERPRETATION

In San Francisco, the acid-fast-bacilli smear identifies the most infectious patients, but patients with smear-negative culture-positive tuberculosis appear responsible for about 17% of tuberculosis transmission.

摘要

背景

痰涂片抗酸杆菌显微镜检查是一种简单快速的检测方法，用于对感染性结核病进行初步诊断。虽然痰涂片抗酸杆菌阴性的肺结核患者传染性低于涂片阳性患者，但理论和实证证据均表明，他们仍可传播结核分枝杆菌。我们旨在评估涂片阴性个体的传播风险。

方法

作为旧金山正在进行的结核病分子流行病学研究的一部分，将具有相同DNA指纹的结核分枝杆菌分离株的肺结核患者归为假定涉及近期传播的聚类。将具有相同DNA的结核分枝杆菌分离株的继发性肺结核病例与其假定的源病例相关联，以评估涂片阴性患者的传播情况。进行敏感性分析以评估由于源病例错误分类、未识别的源病例和HIV-1合并感染导致的潜在偏倚。

结果

报告了1574例培养阳性的肺结核患者，其中1359例（86%）有DNA指纹。在71个感染了指纹匹配菌株的患者聚类中，28个（39%[95%CI 28-52]）有涂片阴性的假定源。在这71个聚类中有183例继发性病例，其中至少32例归因于涂片阴性患者的感染（17%[12-24]）。涂片阴性患者与涂片阳性患者的相对传播率计算为0.22（95%CI 0.16-0.32）。HIV-1状态的敏感性分析和分层对这些估计没有影响。