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

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>The <it>Mycobacterium tuberculosis </it>drug-susceptible strain, named <it>MTZ </it>strain, was genetically characterized by IS<it>6110</it>-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 <it>MTZ </it>strain was so highly transmitted among the population were also analyzed.</p> <p>Results</p> <p>The genetic profile of the <it>MTZ </it>strain was rare and not widely distributed in our area or elsewhere. The patients affected did not show any notable risk factor for TB.</p> <p>Conclusion</p> <p>The <it>M. tuberculosis </it>strain <it>MTZ</it>, might have particular transmissibility or virulence properties, and we believe that greater focus should be placed on stopping its widespread dissemination.</p