Standardised PCR-based Molecular Epidemiology of Tuberculosis in the Brussels-Capital Region

¹ Laboratoire Tuberculose et Mycobactéries, Institut Pasteur - Institut Scientifique de Santé Publique, Brussels, Belgium
² Laboratoire des Mécanismes Moléculaires de la Pathogenèse Bactérienne, INSERM U629, Institut Pasteur, Lille, France
³ Belgian Lung and Tuberculosis Association, Brussels, Belgium

^* To whom correspondence should be addressed. E-mail: mfauville{at}pasteur.be.

	Abstract

A population-based molecular-epidemiology investigation has been undertaken to evaluate tuberculosis transmission and control in the Brussels-Capital Region.

All tuberculosis cases reported from January 2003 to December 2004 were investigated. Five hundred thirty-six Mycobacterium tuberculosis isolates (89% of culture positive samples) were genotyped by the newly standardized 24-loci based mycobacterial interspersed repetitive unit-variable number tandem repeat typing, spoligotyping and IS6110 fingerprinting.

Thirty percent of all patients were grouped based on strain-clusters, suggesting a transmission index of 20%. An unsuspected outbreak entailing at least 23 patients was evidenced by molecular typing analysis and confirmed by contact tracing. Foreign-born accounted for 79% of the studied patients, including 37.9% illegal immigrants and asylum seekers. Among foreign-born patients, asylum seekers and illegal immigrants were significantly less in strain-clusters than settled residents.

Tuberculosis in the European capital is a bi-faceted problem, comprising both persisting recent transmission and "imported diseases". Molecular epidemiology based on real-time genotyping techniques has proven invaluable in better understanding TB transmission. However, it will most efficiently contribute to TB control, when implemented in an integrated Public Health system.