Unsuspected and extensive transmission of a drug-susceptible Mycobacterium tuberculosisstrain

Abstract

BackgroundA 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.MethodsThe 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.ResultsThe 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.ConclusionThe 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.

Global Study of IS 6110 in a Successful Mycobacterium tuberculosis Strain: Clues for Deciphering Its Behavior and for Its Rapid Detection

“…A large unsuspected TB outbreak involving 85 patients in Zaragoza, Spain, in 2001 to 2004 was attributed to the M. tuberculosis Zaragoza strain (35). The lack of the TbD1 region described here confirms that Zaragoza is a modern strain, in agreement with our previous work showing that the strain belongs to principal genetic group 3 (PGG-3) (35).…”

“…The lack of the TbD1 region described here confirms that Zaragoza is a modern strain, in agreement with our previous work showing that the strain belongs to principal genetic group 3 (PGG-3) (35). Other authors found that isolates belong- a Results of the analysis to detect the specificity of the IS6110 localization in 100 different clinical isolates are shown.…”

“…Unlike H37Rv, M. bovis BCG, and M. bovis AF2122/97, the Zaragoza strain carries IS6110 in this locus inserted at a different point, 3 nucleotides from the end of a direct repeat sequence. The analysis of the DR region indicated an 863-bp deletion that is reflected in its discriminative spoligotype, which lacks amplified spacers 24 to 40 (35). Since 8-nucleotide repeats flanking the insertion were detected, it seems that this copy was the consequence of transposition; therefore, we cannot determine whether IS6110 is implicated in the process of deletion of the adjacent region (Fig.…”

Analysis of Mutations in Streptomycin-Resistant Strains Reveals a Simple and Reliable Genetic Marker for Identification of the Mycobacterium tuberculosis Beijing Genotype

“…Interestingly, this insertion is exclusive to the Beijing family of M. tuberculosis isolates and has led to the development of a method for screening M. tuberculosis strains (using either purified DNA or directly on respiratory samples) and reliably identifying those belonging to the Beijing family of strains. (12), and 13 that were Mycobacterium africanum (Table 1). Overall, this collection included samples that were representative of most of the M. tuberculosis genetic lineages that have been described (13).…”

Genomic Diversity of Mycobacterium tuberculosis Complex Strains in Cantabria (Spain), a Moderate TB Incidence Setting

“…described Madrid 1 and Madrid 2 spoligopatterns with their corresponding MIT as probable specific clonal complexes in Spain [ 31 ]. Lopez Calleja et al described a strain, MTZ , causing a large cluster (85 isolates) in Zaragoza, which is also represented (MIT157) in our population [ 30 ]. Another significant finding in our phylogeoraphic structure is that we shared the majority of the clustered patterns with Belgium and Great Britain.…”