The current study evaluated Mycobacterium tuberculosis isolates from Rio de Janeiro, Brazil, for genomic deletions. One locus in our panel of PCR targets failed to amplify in ϳ30% of strains. A single novel long sequence polymorphism (>26.3 kb) was characterized and designated RD Rio . Homologous recombination between two similar protein-coding genes is proposed as the mechanism for deleting or modifying 10 genes, including two potentially immunogenic PPE proteins. The flanking regions of the RD Rio locus were identical in all strains bearing the deletion. Genetic testing by principal genetic group, spoligotyping, variable-number tandem repeats of mycobacterial interspersed repetitive units (MIRU-VNTR), and IS6110-based restriction fragment length polymorphism analysis cumulatively support the idea that RD Rio strains are derived from a common ancestor belonging solely to the Latin American-Mediterranean spoligotype family. The RD Rio lineage is therefore the predominant clade causing tuberculosis (TB) in Rio de Janeiro and, as indicated by genotypic clustering in MIRU-VNTR analysis, the most significant source of recent transmission. Limited retrospective reviews of bacteriological and patient records showed a lack of association with multidrug resistance or specific risk factors for TB. However, trends in the data did suggest that RD Rio strains may cause a form of TB with a distinct clinical presentation. Overall, the high prevalence of this genotype may be related to enhanced virulence, transmissibility, and/or specific adaptation to a Euro-Latin American host population. The identification of RD Rio strains outside of Brazil points to the ongoing intercontinental dissemination of this important genotype. Further studies are needed to determine the differential strain-specific features, pathobiology, and worldwide prevalence of RD Rio M. tuberculosis.Tuberculosis (TB) is a preventable and curable infectious disease that nonetheless remains a significant cause of morbidity and mortality in resource-poor nations (14). TB also threatens to reemerge in developed nations as a consequence of increased immigration, its synergy with the human immunodeficiency virus (HIV)/AIDS epidemic, and a deprioritization of TB control efforts in public health policy (64). The principal etiologic agent of human TB is Mycobacterium tuberculosis, but other species within the M. tuberculosis complex (MTC), such as "Mycobacterium canettii" (proposed name), Mycobacterium africanum, and Mycobacterium bovis, are also known to cause TB in humans (30). Although the MTC is considered a relatively homogenous taxon at the DNA sequence level, an increasing number of species-, lineage-, and strain-specific genetic variations have been revealed by the identification of multicopy repeat elements, targeted interrogations of specific genetic loci, and the comparison of whole-genome sequences of several MTC species and strains (21,24,31). These differences have been exploited as markers for epidemiological purposes and/or to assist in the identific...

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OBJETIVO: Identificar micobactérias não tuberculosas (MNT) isoladas de sítios estéreis em pacientes internados no Hospital Universitário Clementino Fraga Filho, Rio de Janeiro (RJ) entre 2001 e 2006. MÉTODOS: Durante o período do estudo, 34 isolados de MNT de sítios estéreis de 14 pacientes, a maioria HIV positivos, foram submetidos a identificação fenotípica e hsp65 PCR-restriction enzyme analysis (PRA, análise por enzimas de restrição por PCR do gene hsp65). RESULTADOS: A maioria dos isolados foi identificada como Mycobacterium avium, seguida por M. monacense, M. kansasii e M. abscessus em menores proporções. CONCLUSÕES: A combinação de PRA, um método relativamente simples e de baixo custo, com algumas características fenotípicas pode fornecer a identificação correta de MNT na rotina de laboratórios clínicos.