Tuberculosis transmission patterns among Spanish-born and foreign-born populations in the city of Barcelona.
During a 2-year period (2003-2004), tuberculosis (TB) transmission in Barcelona and the factors related to transmission among the Spanish- and foreign-born populations were studied by molecular epidemiology. Data were obtained from TB cases and Conventional Contact Tracing registries and genotyping was performed using restriction fragment length polymorphism (RFLP)-IS6110 and MIRU12 as a secondary typing method. Of the 892 TB cases reported, 583 (65.3%) corresponded to Spanish-born and 309 (34.6%) to foreign-born. Six hundred and eighty-seven cases (77%) were confirmed by culture. RFLP typing of 463/687 (67.4%) isolates was performed, revealing 280 (60.5%) unique and 183 (39.5%) shared patterns, which were grouped into 65 clusters. Spanish-born individuals were significantly more clustered than foreign-born individuals (44.6% vs. 28.8%; p 0.016). Clustering in foreign-born individuals was associated with HIV (p 0.051, odds ratio = 3.1, 95% confidence interval 1-10.9) and alcohol abuse (p 0.022), whereas, in the Spanish-born individuals, clustering was associated with age in the range 21-50 years, (p 0.024). Of the total clusters, 36/65 (55.3%) included only Spanish-born patients, whereas 22/65 (33.8%) included individuals from both populations. In mixed clusters, the index case was Spanish-born in 53% and foreign-born in 47%. Among the foreign-born, 2.8% were ill on arrival, 30% developed TB within the first year and 50.3% developed TB within the first 2 years; 58.3% were from South America. In conclusion, half of the foreign-born TB patients developed the disease during the first 2 years after arrival, which, in most cases, was the result of endogenous reactivation. Recent TB transmission among Spanish-born and foreign-born populations, as well as bidirectional transmission between communities, contributed significantly to the burden of TB in Barcelona, suggesting the need to improve Public Health interventions in both populations.
Borrell
S
S
Servei de Microbiologia, CDB. H. Clínic de Barcelona (HCB)-IDIBAPS, Universitat de Barcelona, Barcelona, Spain.
Español
M
M
Orcau
A
A
Tudó
G
G
March
F
F
Caylà
J A
JA
Jansà
J M
JM
Alcaide
F
F
Martín-Casabona
N
N
Salvadó
M
M
Martinez
J A
JA
Vidal
R
R
Sanchez
F
F
Altet
N
N
Rey
E
E
Coll
P
P
González-Martín
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000437:Alcoholism / Q000150:complications; D015373:Bacterial Typing Techniques / Q000379:methods; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D016172:DNA Fingerprinting / Q000379:methods; D004269:DNA, Bacterial / Q000235:genetics; D054242:Emigrants and Immigrants; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000150:complications; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D014376:Tuberculosis / Q000453:epidemiology* / Q000635:transmission*; D055815:Young Adult
D004269:DNA, Bacterial