Mycobacterium tuberculosis genotypes and predominant clones among the multidrug-resistant isolates in Spain 1998-2005.

Although the incidence of tuberculosis (TB) is gradually decreasing in Spain, there is an increase in the proportion of foreign-born cases. This changing scenario is slowly shifting the local TB epidemiology from endemic to imported cases with an increased risk for multidrug-resistant (MDR) and extensively drug resistant (XDR) strains of Mycobacterium tuberculosis complex. MDR/XDR strains from Spain (n=366 MTBC isolates, 1 strain per patient) isolated between 1998 and 2005 were retained for this retrospective analysis. All strains were analyzed by spoligotyping, while 12-loci MIRU-VNTR data were available for 106 isolates from 2003 to 2005. Demographic, phylogenetic, and epidemiologic analyses using anonymized data were collected and analyzed using the SITVIT2 database. Our study provides with a first snapshot of genetic diversity of MDR/XDR-TB in several autonomous regions of Spain. It highlights significantly more of SIT1/Beijing and SIT66/BOV MDR isolates (5.7% and 7.38% respectively) and increasingly more foreign-born cases from Eastern Europe. Future studies should focus on shared genotypes between Spanish and foreign-born patients to decipher the modes of transmission and risk factors involved, and decipher the proportion of imported cases of active disease versus cases of reactivation of latent TB infection among foreign-born individuals.

In-depth analysis of the genome sequence of a clinical, extensively drug-resistant Mycobacterium bovis strain.

Although human-to-human transmission of Mycobacterium bovis strains and other members of the animal lineage of the tubercle bacilli is a rare event, an extensively drug resistant (XDR) strain, named M. bovis B strain, caused a lethal outbreak in the nineties in Spain. The genome of M. bovis B strain was re-sequenced by SOLiD platform and mapped to the reference M. bovis AF2122/97. The genetic polymorphisms detected have been analysed in depth. One hundred and fifty-eight specific non-synonymous SNPs were detected; ninety-two of these were non-conservative. In addition, one specific 3195-bp insertion could be identified as an ABC transporter gene by homology with tbd2 gene, which was found to be present in other clinical M. bovis strains. Its peculiar phenotype profile of resistance was explained by molecular characteristics, including a 5685-bp specific deletion that revealed a novel polymorphism associated with resistance to paraminosalicilic acid. From a phylogenetical point of view, according to the SNPs detected, M. bovis B could be included into the clonal complex M. bovis European 2. This is the first time that a deep analysis of the whole-genome sequencing of an extensively drug-resistant M. bovis strain is detailed. It offers the explanation for the resistance and found several data to be incorporated for future research.