title: Characterization of clonal complexity in tuberculosis by mycobacterial interspersed repetitive unit-variable-number tandem repeat typing.
abstract: In recent years, the application of molecular tools has shown us that clonal complexity in infection by Mycobacterium tuberculosis is not anecdotal. Exogenous reinfections, mixed infections, compartmentalization, and microevolution are different aspects of this issue. The detection and characterization of clonal variants of M. tuberculosis by standard genotyping methods is laborious and frequently requires expertise. Our aim was to evaluate a new genotyping PCR-based method for M. tuberculosis, mycobacterial interspersed repetitive unit-variable-number tandem repeat typing (MIRU-VNTR), as a potential tool to simplify and optimize the clonal analysis of tuberculosis. MIRU-VNTR was able to detect mixed clonal variants in vitro, even for clones at low ratios (1:99). This technique was prospectively applied to search for cases infected by more than one clone. Clonal variants within the same host were detected in 3 out of 115 cases (2.6%), including cases with clones which were indistinguishable by restriction fragment length polymorphism or spoligotyping. In one case, coinfecting clonal variants differed in antibiotic susceptibilities. MIRU-VNTR was applied to cases with proven polyclonal infection, and it succeeded in detecting the coinfecting strains and proved useful in confirming cases of compartmentalized infection. MIRU-VNTR is a simple, rapid, and sensitive method which could facilitate and optimize the identification and characterization of clonal complexity in M. tuberculosis infection.
authors.affiliation: Servicio de Microbiología y Enfermedades Infecciosas, Hospital Gregorio Marañón, C/ Dr. Esquerdo 46, 28007 Madrid, Spain. dgviedma@microb.net
authors.forename: Darío
authors.initials: D
authors.lastname: García de Viedma
authors.forename: Noelia
authors.initials: N
authors.lastname: Alonso Rodriguez
authors.forename: Sandra
authors.initials: S
authors.lastname: Andrés
authors.forename: Maria Jesús
authors.initials: MJ
authors.lastname: Ruiz Serrano
authors.forename: Emilio
authors.initials: E
authors.lastname: Bouza
mesh_terms: D004251:DNA Transposable Elements; D014644:Genetic Variation; D006801:Humans; D018598:Minisatellite Repeats; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000382:microbiology*
chemical_list: D004251:DNA Transposable Elements