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背景:分子流行病学在近期的结核病传播中的重要性得到了加强,但同时也发现了一些与传统流行病学的显著区别。 目的:1.在城市中心区的结核病高流行区(163/100000)和有成簇危险的人群中用RFLP法确定成簇病例的百分比。2.比较传统接触者追踪法(CCT)与RFLP法的作用。 分析:1997-1998年间巴塞罗纳市Ciutat Vella区收集的培养阳性的165例标本,利用IS6110和pTBN12(PGRS)序列进行RFLP分析:对251例公布的病例中的171例(68.1％)进行了接触者追踪调查。通过计算比值比(OR)、使用95％的可信区间(CI)评价它们之间的联系。多变量的分析采用逻辑回归。结果:通过RFLP分析,发现76例(46.0％)的分离株在IS6110和PGRS序列上有成簇现象,通过传统接触者追踪法(CCT),在858名接触者中,发现了30名新病人,57名病人存在关联。就RFLP和CCT调查结果来看,主要危险因素为静脉吸毒(IVDU)。44名独居者病例未包括在传统接触者追踪中,50％的病例用RFLP分析存在成簇。RFLP和CCT法的符合率为8/13(61.5％);5例不符合者为新近的非洲移民。在随后的RFLP分析中15/55例病例发现有流行病学关联。 结论:成簇病例的百分率很高。CCT在发现新病例时很有用,但在追踪传播路径时存在缺陷。CCT的覆盖面需要在被忽视的个体及与RFLP结果的符合率方面提高。
Background: The importance of molecular epidemiology in the recent transmission of tuberculosis has been enhanced, but some significant differences from traditional epidemiology have also been found. Objectives: 1. To determine the percentage of clustered cases using the RFLP method in areas with high prevalence of tuberculosis (163/100000) in urban centers and in populations at risk of clustering. 2. Compare traditional contact tracing (CCT) with RFLP. Analysis: A positive culture of 165 specimens collected in the Ciutat Vella district of Barcelona between 1997 and 1998 and RFLP analysis using the IS6110 and pTBN12 (PGRS) sequences: 171 of the 251 published cases (68.1%) were performed Contact follow-up survey. The odds ratio (OR) was used to assess the association between them using a 95% confidence interval (CI). Multivariate analysis uses logistic regression. RESULTS: Seventy-six (46.0%) isolates were clustered on the IS6110 and PGRS sequences by RFLP analysis. Of 858 contacts, 30 new patients were found by traditional contact tracing (CCT) , 57 patients are related. In the RFLP and CCT surveys, the main risk factor was intravenous drug use (IVDU). Forty-four single-placers were not included in the traditional contact tracing and 50% were clustered by RFLP analysis. The compliance rate of RFLP and CCT was 8/13 (61.5%); 5 of them were newly immigrants from Africa. Epidemiological associations were found in 15/55 of the subsequent RFLP analyzes. Conclusion: The percentage of clustered cases is high. CCT is useful in detecting new cases, but has drawbacks in tracking the transmission path. CCT coverage needs to be improved in terms of neglected individuals and their compliance with RFLP results.