Recent studies in a BALB/c mouse model demonstrated differential interaction of various M. tuberculosis Beijing isolates ( 15, 23, 37). tuberculosis strains but not against selected genotypes (called escape variants), such as M. It has been hypothesized that the BCG-induced immunological defense may protect against most M. tuberculosis genotypes predominate, suggesting selective advantages of these strains ( 15, 19, 36, 37). DNA fingerprinting of the causative agent, Mycobacterium tuberculosis, has revealed that in high-incidence areas, where more than 97% of these tuberculosis deaths occur, particular M. Current trends suggest that these numbers could rise to 12 million and 4 million, respectively, by the year 2010 ( 17). tuberculosis strains.ĭespite mass Mycobacterium bovis BCG vaccination and antituberculosis drugs, tuberculosis is one of the major killers among infectious diseases, causing about eight million cases and two to three million deaths annually ( 10). tuberculosis strains belonging to the Beijing/W lineage, as described in this work, will facilitate further studies on the spread and characterization of this widespread genotype family of M. A standardized definition for the identification of M. The usefulness of the reference patterns was also assessed with large DNA fingerprint databases in two other European countries and for identification strains from the W lineage found in the United States. These reference patterns gave a sensitivity of 98.1% and a specificity of 99.7% for identifying Beijing strains (defined by spoligotyping) in an international database of 1,084 strains. A set of 19 Beijing reference RFLP patterns was selected to retrieve all Beijing strains from the Dutch database. tuberculosis isolates representative of the IS 6110 RFLP genotypes found in The Netherlands, strains of two clades had spoligotypes characteristic of the Beijing lineage. In a well-characterized collection of 1,020 M. In this study the suitability and comparability of these three genetic markers to identify members of the Beijing lineage were evaluated. Beijing genotype strains, including W strains, have been characterized by their highly similar multicopy IS 6110 restriction fragment length polymorphism (RFLP) patterns, deletion of spacers 1 to 34 in the direct repeat region (Beijing spoligotype), and insertion of IS 6110 in the genomic dnaA-dnaN locus. They are increasingly reported in other areas of the world and are frequently associated with tuberculosis outbreaks and drug resistance. Mycobacterium tuberculosis Beijing genotype strains are highly prevalent in Asian countries and in the territory of the former Soviet Union.
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