Fil: Abascal, Estefanía. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; EspañaFil: Herranz, Marta. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; EspañaFil: Acosta, Fermín. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; EspañaFil: Agapito, Juan. TB Research Unit, Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima; Peru.Fil: Cabibbe, Andrea M. Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milan; Italia.Fil: Monteserín, Johana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Epidemiología; Argentina.Fil: Ruiz Serrano, María Jesús. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; España.Fil: Gijón, Paloma. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; España.Fil: Fernández-González, Francisco. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; España.Fil: Lozano, Nuria. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; España.Fil: Chiner-Oms, Álvaro. Unidad Mixta Genómica y Salud, Centro Superior de Investigación en Salud Pública (FISABIO)-Universitat de València; España.Fil: Cáceres, Tatiana. TB Research Unit, Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima; Peru.Fil: Gómez Pintado, Pilar. General Subdirection of Penitentiary Health - Penitentiary Institutions - Ministry of Interior of Spain; España.Fil: Acín, Enrique. General Subdirection of Penitentiary Health - Penitentiary Institutions - Ministry of Interior of Spain; España.Fil: Muñoz, Patricia. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; EspañaFil: Comas, Iñaki. Instituto de Biomedicina de Valencia (IBV) Consejo Superior de Investigaciones Científicas (CSIC); España.Fil: Cirillo, Daniela M. Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milan; Italia.Fil: Ritacco, Viviana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Epidemiología; Argentina.Fil: Gotuzzo, Eduardo. TB Research Unit, Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima; Peru.Fil: García de Viedma, Dario. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid; España.It is relevant to evaluate MDR-tuberculosis in prisons and its impact on the global epidemiology of this disease. However, systematic molecular epidemiology programs in prisons are lacking. A health-screening program performed on arrival for inmates transferred from Peruvian prisons to Spain led to the diagnosis of five MDR-TB cases from one of the biggest prisons in Latin America. They grouped into two MIRU-VNTR-clusters (Callao-1 and Callao-2), suggesting a reservoir of two prevalent MDR strains. A high-rate of overexposure was deduced because one of the five cases was coinfected by a pansusceptible strain. Callao-1 strain was also identified in 2018 in a community case in Spain who had been in the same Peruvian prison in 2002-5. A strain-specific-PCR tailored from WGS data was implemented in Peru, allowing the confirmation that these strains were currently responsible for the majority of the MDR cases in that prison, including a new mixed infection.