[Recent transmission of tuberculosis in Madrid (Spain): usefulness of molecular techniques].
BACKGROUND
Recent studies suggest that many tuberculosis cases in urban areas result from recent transmission. The aim of this study was to determine patterns of tuberculosis transmission in Madrid.


METHODS
A prospective population-based molecular epidemiological study of patients diagnosed of tuberculosis was conducted in three urban districts of Madrid (455.050 inhabitants) during 1997-1998. Clinical, demographic and epidemiological data were reviewed. Patients were included in clusters when their isolates contained: a) six or more IS6110 bands in an identical pattern, or b) five or fewer IS6110 bands that matched identically and had an identical spoligotyping pattern.


RESULTS
Of 207 positive-culture patients, 148 (71,5%) were DNA fingerprinted. A total of 18 clusters which included 62 patients (41,9%) were identified. Clusters contained between 2 and 12 cases. Risk factors for clustering included: age < 35 years (OR = 4,1, 95% CI: 1,9-8,9), injection drug use (OR = 4,7, 95% CI: 1,6-14,8), HIV infection (OR = 2,7, 95% CI: 1,1-6,8), and a history of imprisonment (OR = 2,9, 95% CI: 1,2-7,2). The epidemiological investigation identified connections among 27% of clustered patients.


CONCLUSIONS
A high proportion of cases of tuberculosis in urban Madrid result from recent transmission. Molecular epidemiology studies give valuable information for urban tuberculosis control.
Iñigo Martínez
J
J
Servicio de Salud Pública del Area 11. Dirección General de Salud Pública. Consejería de Sanidad. Comunidad de Madrid. jesus.inigo@comadrid.es
Chaves Sánchez
F
F
Arce Arnáez
A
A
Alonso Sanz
M
M
Palenque Mataix
E
E
Jaén Herreros
F
F
Martínez Martínez
M T
MT
Gómez García
M
M
Rodríguez Noriega
A
A
D000328:Adult; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D014376:Tuberculosis / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission
D004269:DNA, Bacterial