Tuberculosis (TB) incidence is decreasing worldwide and eradication is becoming plausible. In low-incidence countries, intervention on migrant populations is considered one of the most important strategies for elimination. However, such measures are inappropriate in European areas where TB is largely endemic, such as Porto in Portugal. We aim to understand transmission chains in Porto through a genetic characterization of Mycobacterium tuberculosis strains and through a detailed epidemiological evaluation of cases.
We genotyped the M. tuberculosis strains using the MIRU-VNTR system. We performed an evolutionary reconstruction of the genotypes with median networks, used in this context for the first time. TB cases from a period of two years were evaluated combining genetic, epidemiological and georeferencing information.
The data reveal a unique complex scenario in Porto where the autochthonous population acts as a genetic reservoir of M. tuberculosis diversity with discreet episodes of transmission, mostly undetected using classical epidemiology alone.
Although control policies have been successful in decreasing incidence in Porto, the discerned complexity suggests that, for elimination to be a realistic goal, strategies need to be adjusted and coupled with a continuous genetic characterization of strains and detailed epidemiological evaluation, in order to successfully identify and interrupt transmission chains.
WHO: Global Tuberculosis Report. Geneva, World Health Organization 2016.
European Centre for Disease Prevention and Control (ECDC) / World Health Organization (WHO) Regional Office for Europe: Surveillance report: tuberculosis surveillance and monitoring in Europe 2016. Stockholm: ECDC; 2016.
DGS: Portugal: Infeção por VIH, SIDA e Tuberculose em números: 2015 . Programa Nacional para a Infecção VIH/SIDA , Direcção Geral de Saúde 2015.
Paulino J, Martins A, Machado M, Gomes M, Gaio AR, Duarte R. Tuberculosis in native- and foreign-born populations in Portugal. Int J Tuber Lung Dis. 2016;20:357–62. CrossRef
Nunes C, Taylor BM. Modelling the time to detection of urban tuberculosis in two big cities in Portugal: a spatial survival analysis. Inter J Tuber Lung Dis. 2016;20:1219–25. CrossRef
Franco I, Sousa P, Gomes M, Oliveira A, Gaio AR, Duarte R. Social profile of the highest tuberculosis incidence areas in Portugal. Revista Portuguesa Pneumologia. 2016;22:50–2. CrossRef
Supply P, Allix C, Lesjean S, Cardoso-Oelemann M, Rüsch-Gerdes S, Willery E, Savine E, Pd H, Hv D, Roring S, et al. Proposal for standardization of optimized mycobacterial interspersed repetitive unit-variable-number tandem repeat typing of Mycobacterium tuberculosis. J Clin Microbiol. 2006;44:4498–510. CrossRefPubMedPubMedCentral
Yuan L, Mi L, Li Y, Zhang H, Zheng F, Li Z. Genotypic characteristics of Mycobacterium tuberculosis circulating in Xinjiang, China. J Infec Dis. 2016;48:108–15. CrossRef
Walker TM, Kohl TA, Omar SV, Hedge J, CDO E, Bradley P, Iqbal Z, Feuerriegel S, Niehaus KE, Wilson DJ, et al. Whole-genome sequencing for prediction of Mycobacterium tuberculosis drug susceptibility and resistance: a retrospective cohort study. Lancet Infec Dis. 2015;15:1193–202. CrossRef
Fitzgibbon MM, Gibbons N, Roycroft E, Jackson S, O'Donnell J, O'Flanagan D, Rogers TR. A snapshot of genetic lineages of Mycobacterium tuberculosis in Ireland over a two-year period, 2010 and 2011. Euro Surveillance. 2013;18
Pérez Del Molino Bernal IC, Lillebaek T, Pedersen MK, Martinez-Martinez L, Folkvardsen DB, Agüero J, Rasmussen EM. Genomic diversity of Mycobacterium tuberculosis complex strains in Cantabria (Spain), a moderate TB incidence setting. PLoS One. 2016;11:e0157266.
Oelemann MC, Diel R, Vatin V, Haas W, Rüsch-Gerdes S, Locht C, Niemann S, Supply P. Assessment of an optimized mycobacterial interspersed repetitive- unit-variable-number tandem-repeat typing system combined with spoligotyping for population-based molecular epidemiology studies of tuberculosis. J Clin Microbiol. 2007;45:691–7. CrossRefPubMed
Roetzer A, Diel R, Kohl TA, Rückert C, Nübel U, Blom J, Wirth T, Jaenicke S, Schuback S, Rüsch-Gerdes S, et al. Whole genome sequencing versus traditional genotyping for investigation of a Mycobacterium tuberculosis outbreak: a longitudinal molecular epidemiological study. PLoS Med. 2013;10:e1001387. CrossRefPubMedPubMedCentral
van Deutekom H, Hoijng SP, de Haas PE, Langendam MW, Horsman A, van Soolingen D, Coutinho RA. Clustered tuberculosis cases: do they represent recent transmission and can they be detected earlier. Am J Respir Crit Care Med. 2004;169:806–10.
Dias M, Gaio R, Sousa P, Correia-Neves M, Ferreira E, Duarte R. Tuberculosis among the homeless, should we change the strategy? Int J Tuber Lung Dis. 2017;21:327–32. CrossRef
Hamblion EL, Menach AL, Anderson LF, Lalor MK, Brown T, Abubakar I, Anderson C, Maguire H, Anderson SR, PHESTP B. Recent TB transmission, clustering and predictors of large clusters in London, 2010-2012: results from first 3 years of universal MIRU-VNTR strain typing. Thorax. 2016;71:749–56. CrossRefPubMedPubMedCentral
- A complex scenario of tuberculosis transmission is revealed through genetic and epidemiological surveys in Porto
João Tiago Guimarães
Catarina L. Santos
- BioMed Central
Neu im Fachgebiet Innere Medizin
Meistgelesene Bücher aus der Inneren Medizin
Mail Icon II