Open Access Highly Accessed Research article

Unsuspected and extensive transmission of a drug-susceptible Mycobacterium tuberculosis strain

Ana Isabel López-Calleja1238, Patricia Gavín1238, Ma Antonia Lezcano13, Ma Asunción Vitoria34, Ma José Iglesias35, Joaquín Guimbao6, Ma Ángeles Lázaro6, Nalin Rastogi7, Ma José Revillo13, Carlos Martín35 and Sofia Samper123*

Author Affiliations

1 Servicio de Microbiología, Hospital Universitario Miguel Servet, Paseo Isabel la Católica, Zaragoza, Spain

2 Instituto Aragonés de Ciencias de la Salud Avda Gómez Laguna, Zaragoza, Spain

3 Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CibeRes) Fundación Caubet-Cimera, Recinto Hospital Joan March, Carretera Soller Km 12, 07110 Bunyola, Mallorca, Spain

4 Servicio de Microbiología, Hospital Clínico Universitario Lozano Blesa Avda Gómez Laguna, Zaragoza, Spain

5 Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza. c/Domingo Miral, Zaragoza, Spain

6 Sección de Vigilancia Epidemiológica, Subdirección Provincial de Salud Pública, C/Ramón y Cajal, Zaragoza, Spain

7 Tuberculosis and Mycobacteria Unit, Institut Pasteur de Guadeloupe, Morne Joliviere, BP 484, 97183-Abymes, Cedex, Guadeloupe, France

8 Laboratorio de Salud Pública, Dirección General de Salud Pública, Ramón y Cajal n° 68, 50004 Zaragoza, Spain

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BMC Pulmonary Medicine 2009, 9:3  doi:10.1186/1471-2466-9-3

Published: 14 January 2009



A large and unsuspected tuberculosis outbreak involving 18.7% of the total of the tuberculosis cases studied, was detected in a population-based molecular epidemiological study performed in Zaragoza (Spain) from 2001 to 2004.


The Mycobacterium tuberculosis drug-susceptible strain, named MTZ strain, was genetically characterized by IS6110-RFLP, Spoligotyping and by MIRU-VNTR typing and the genetic patterns obtained were compared with those included in international databases. The characteristics of the affected patients, in an attempt to understand why the MTZ strain was so highly transmitted among the population were also analyzed.


The genetic profile of the MTZ strain was rare and not widely distributed in our area or elsewhere. The patients affected did not show any notable risk factor for TB.


The M. tuberculosis strain MTZ, might have particular transmissibility or virulence properties, and we believe that greater focus should be placed on stopping its widespread dissemination.