title: [Recent transmission of tuberculosis in an area with low incidence: epidemiological and molecular study].
abstract: BACKGROUND
  Few reports have analysed the transmission of tuberculosis in rural areas with a low incidence of disease.
  
  
  METHODS
  A population-based molecular epidemiological study of patients with tuberculosis, diagnosed by culture, was conducted in Segovia (Spain) between 1995 and 1999. Clinical, demographic and epidemiological data were reviewed. Patients whose clinical isolates of Mycobacterium tuberculosis had identical restriction-fragment-length-polymorphism (RFLP) patterns with IS6110 and spoligotyping were included in clusters.
  
  
  RESULTS
  Of 96 patients with positive-culture for M. tuberculosis complex, 6 were considered as false-positive results. The mean incidence rate was 12.3 cases/100,000 inhabitants. Median age was 50.3 (SD: 23.1), 14% was HIV-infected, and 92% of them were living in urban areas (p < 0.01). There were no cases of primary resistance to isoniazid. DNA fingerprint was performed in 87 samples. We identified 8 clusters including 24 patients (27.7%). Clusters had between 2 and 6 cases. Patients aged < 35 years (OR = 3.1; CI 95%, 1.0-9.6) and with lung involvement (OR = 6.8; CI 95%, 1.3-46.4) were more represented in the clusters. Classical epidemiological investigation confirmed a recent transmission in 33% of clustered cases.
  
  
  CONCLUSIONS
  The use of both classical and molecular epidemiology reveals the existence of recent transmission cases of tuberculosis in an area with a low incidence of the disease.
authors.affiliation: Medicina Interna Hospital General de Segovia. Spain. jeizaga@hgse.insalud.es
authors.forename: Jorge
authors.initials: J
authors.lastname: Elizaga
authors.forename: Pablo
authors.initials: P
authors.lastname: Carrero
authors.forename: Jesús
authors.initials: J
authors.lastname: Iñigo
authors.forename: Fernando
authors.initials: F
authors.lastname: Chaves
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004269:DNA, Bacterial / Q000032:analysis; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D013030:Spain; D013997:Time Factors; D014376:Tuberculosis / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*
chemical_list: D004269:DNA, Bacterial