The application of genotyping tools to the analysis of tuberculosis (TB) has allowed us to identify clinical isolates of Mycobacterium tuberculosis to strain level. M. tuberculosis fingerprinting has been applied at different levels: a) in the laboratory, to optimize identification of cross-contamination events which can lead to a false diagnosis; b) in the patient, to determine whether recurrences are due to reactivations or exogenous reinfections or to identify cases coinfected by more than one strain; c) at the micropopulation level, to identify clusters of cases infected by the same strains (recent transmission) and to differentiate them from orphan cases that are most probably due to reactivations; and d) at the macropopulation level, to define the global distribution of M. tuberculosis lineages, to monitor the international spread of high-risk strains, and to explore the evolutionary features of M. tuberculosis. In recent years, important methodological and strategic advances have been applied at these different levels of analysis. Rather than provide an exhaustive review, the present study focuses on specific advances in micropopulation and macropopulation analysis.
La aplicación de estrategias de genotipado al análisis de la tuberculosis (TB) ha permitido discriminar los aislados de Mycobacterium tuberculosis a nivel de cepa en distintos contextos: a) en el laboratorio, para optimizar eventos de contaminación cruzada; b) en el paciente, para discriminar recurrencias debidas a reactivaciones o reinfecciones e identificar casos con infecciones mixtas; c) en el contexto “micropoblacional”, para identificar casos infectados por una misma cepa (transmisión reciente), y d) en el contexto “macropoblacional”, para definir la distribución internacional de linajes de M. tuberculosis, de cepas de alto riesgo o analizar aspectos evolutivos. En los últimos años hemos asistido a avances metodológicos y analíticos en cada uno de los contextos mencionados. Esta revisión no pretende ofrecer un análisis exhaustivo de éstos, sino destacar algunos avances de especial interés en el contexto del análisis micro y macropoblacional.