title: Ten-year population-based molecular epidemiological study of tuberculosis transmission in the metropolitan area of Madrid, Spain.
abstract: METHODS
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  Youth and pleural effusion were identified as risk factors for clustering. These findings may help adjust TB control and contact tracing strategies.
authors.affiliation: Servicio de Microbiologia, Hospital Universitario de Getafe, Ctra/Toledo Km 12,5, Getafe, Madrid, Spain. jcacho.hugf@salud.madrid.org
authors.forename: J
authors.initials: J
authors.lastname: Cacho Calvo
authors.forename: J
authors.initials: J
authors.lastname: Astray Mochales
authors.forename: A
authors.initials: A
authors.lastname: Pérez Meixeira
authors.forename: A
authors.initials: A
authors.lastname: Ramos Martos
authors.forename: M
authors.initials: M
authors.lastname: Hernando García
authors.forename: M
authors.initials: M
authors.lastname: Sánchez Concheiro
authors.forename: J R
authors.initials: JR
authors.lastname: Domínguez Pérez
authors.forename: A B
authors.initials: AB
authors.lastname: Gómez
authors.forename: S
authors.initials: S
authors.lastname: Samper
authors.forename: C
authors.initials: C
authors.lastname: Martín
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000145:classification; D012150:Polymorphism, Restriction Fragment Length; D011446:Prospective Studies; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D014505:Urban Population