Ten-year population-based molecular epidemiological study of tuberculosis transmission in the metropolitan area of Madrid, Spain.

SETTING: The epidemiology of tuberculosis (TB) in urban populations is changing. Combining conventional epidemiological techniques with DNA fingerprinting of Mycobacterium tuberculosis can improve our understanding of how TB is transmitted. OBJECTIVE: To improve the definition of molecular epidemiology of TB over 10 years in an area of Europe not previously studied. DESIGN: A population-based retrospective study was conducted in the Autonomous Community of Madrid, Spain, from 1992 to 1998; from 1999 to 2001, the study was prospective. The study population consisted of all patients for whom positive culture and full clinical and demographic data were available. All strains were typed by RFLP. Non-clustered patients were compared with clustered patients and studied using univariate analysis and a logistic regression model. RESULTS: Of 448 patients studied, 228 (50.7%) were clustered. Youth was the strongest risk factor associated with clustering. Pleural effusion was also found to be associated with clustering. An epidemiological link was found in only 85 (37.4%) of the 228 patients belonging to a cluster. CONCLUSION: Youth and pleural effusion were identified as risk factors for clustering. These findings may help adjust TB control and contact tracing strategies.

Recurrent tuberculosis from 1992 to 2004 in a metropolitan area.

The proportion of recurrent tuberculosis (TB) cases caused by re-infection has varied widely in previous studies. The aim of the present study was to determine the relative frequency of relapse and exogenous re-infection in patients with second episodes of TB, using DNA fingerprinting. A population-based retrospective longitudinal descriptive study was conducted in Madrid (Spain) during 1992-2004. The study consisted of 645 patients with culture-confirmed TB. Of these, 20 (3.1%) were retained because they presented with a second isolate of Mycobacterium tuberculosis. Finally, 12 of these cases were excluded because they did not complete the full treatment prescribed. All strains were typed by restriction fragment length polymorphism analysis and some by mycobacterial interspersed repetitive unit-variable number of tandem repeats analysis. The patients with recurrent TB were compared with those without recurrent TB. For seven out of the eight patients, the restriction fragment length polymorphism patterns of the Mycobacterium tuberculosis strains from the episodes of recurrent disease showed identical initial and final genotypes, indicating relapse; the remaining recurrent case showed different genotypes, suggesting exogenous re-infection. Re-infection is possible among people in developed countries, but the rates are lower than those occurring in high-risk areas. The risk factors for recurrent tuberculosis should be taken into account in the follow-up of treatment and tuberculosis control strategies.

Tuberculosis en la población inmigrante del Área 10 de Madrid / Tuberculosis in the Madrid Area 10 immigrant population

A raíz de la aparición y crecimiento del fenómeno inmigratorio desde países extranjeros a España iniciado a primeros de esta década, se ha observado en determinadas regiones geográficas de nuestro país y en áreas metropolitanas de grandes ciudades como Madrid y Barcelona una desaceleración en la caída de las tasas de tuberculosis (TB) respecto a años anteriores con un aumento progresivo del porcentaje de casos en el colectivo inmigrante. Este fenómeno social planteaun nuevo reto sanitario en un país como el nuestro con importantes carencias -entre ellas, la ausencia de un Programa Nacional contra la Tuberculosis- que dificultará el control de la enfermedad y ralentizará el declive de unas tasas (en España en torno a 25-30/100.000 en 2003) que poco a poco y siempre con atraso respecto a nuestro entorno (en Holanda8-9/100.000) venían mejorando. En el presente estudio descriptivo analizamos el papel y las características del fenómeno inmigratorio y su evolución en el Área Sanitaria 10 de la Comunidad Autónoma de Madrid en el período 1992-2003, las dificultades que la nueva situación ha planteado y sus posibles soluciones

Based on the appearance and growth of the immigration phenomenon from foreign countries to Spain that began at the onset of this decade, the slowdown in the rate of decrease of tuberculosis (TB) with a progressive increase of the percentage of cases in the immigrant group regarding previous years has been observed in certain geographic regions of our countryand in the metropolitan areas of large cities such as Madrid and Barcelona. This social phenomenon poses a new healthcare challenge in a country such as ours with important deficiencies, among them the absence of a National Program against Tuberculosis, that will make it difficult to control the disease and will slow down the decline of some rates (in Spain, about 25-30/100000 in 2003) that had been improving little by little and always with a delay regarding our setting ((inHolland 8-9/100000). We analyze the role and characteristics of the immigration phenomenon and its evolution in the Madrid Regional Community Healthcare Area 10 in the period 1992-2003. We also analyze the difficulties that the new situation has posed and their possible solutions