Barnes P F, Yang Z, Preston-Martin S, Pogoda J M, Jones B E, Otaya M, Eisenach K D, Knowles L, Harvey S, Cave M D
Department of Medicine, University of Southern California School of Medicine, Los Angeles, USA.
JAMA. 1997 Oct 8;278(14):1159-63.
Recent studies suggest that many tuberculosis cases in urban areas result from recent transmission. Delineation of the epidemiologic links between patients is important to optimize strategies to reduce tuberculosis transmission.
To identify epidemiologic links among recently infected urban patients with tuberculosis.
Prospective evaluation of patients with tuberculosis.
Central Los Angeles, Calif.
A total of 162 patients who had culture-proven tuberculosis.
Patients were prospectively interviewed to identify their contacts and whereabouts. The IS6110-based and pTBN12-based restriction fragment length polymorphism analyses were performed on Mycobacterium tuberculosis isolates. Patients whose isolates had identical or closely related restriction fragment length polymorphism patterns were considered a cluster. Unconditional logistic regression was used to identify independent predictors of clustering.
Relationship of clinical and epidemiologic variables to clustering.
A total of 96 (59%) of 162 patients were in 8 clusters. Only 2 of the 96 clustered patients named others in the cluster as contacts. The degree of homelessness was an independent predictor of clustering. Compared with nonclustered patients, patients in 6 clusters were significantly more likely to have spent time at 3 shelters and other locations when at least 1 patient in the cluster was contagious, and these locations were independent predictors of clustering. Among nonhomeless persons, clustered patients were significantly more likely than nonclustered patients to have used daytime services at 3 shelters.
(1) Traditional contact investigation does not reliably identify patients infected with the same M tuberculosis strain, and (2) locations at which the homeless congregate are important sites of tuberculosis transmission for homeless and nonhomeless persons. Measures that reduce tuberculosis transmission should be based on locations rather than on personal contacts.
近期研究表明，城市地区的许多结核病病例是近期传播所致。明确患者之间的流行病学联系对于优化减少结核病传播的策略至关重要。
确定近期感染的城市结核病患者之间的流行病学联系。
对结核病患者进行前瞻性评估。
加利福尼亚州洛杉矶市中心。
共有162例经培养证实患有结核病的患者。
对患者进行前瞻性访谈，以确定其接触者和行踪。对结核分枝杆菌分离株进行基于IS6110和pTBN12的限制性片段长度多态性分析。分离株具有相同或密切相关的限制性片段长度多态性模式的患者被视为一个聚类。采用无条件逻辑回归来确定聚类的独立预测因素。
临床和流行病学变量与聚类的关系。
162例患者中有96例（59%）属于8个聚类。96例聚类患者中只有2例指出聚类中的其他人为接触者。无家可归程度是聚类的独立预测因素。与非聚类患者相比，当聚类中的至少1例患者具有传染性时，6个聚类中的患者在3个收容所和其他场所停留的可能性显著更高，这些场所是聚类的独立预测因素。在非无家可归者中，聚类患者比非聚类患者更有可能在3个收容所使用日间服务。
（1）传统的接触者调查不能可靠地识别感染相同结核分枝杆菌菌株的患者，（2）无家可归者聚集的场所是无家可归者和非无家可归者结核病传播的重要地点。减少结核病传播的措施应基于场所而非个人接触。
