The effective control of tuberculosis (TB) requires targeted efforts to break transmission. The lack of obvious symptoms for long periods after infection delays diagnosis, facilitating transmission. Public Health authorities in Porto have been performing a meritorious effort to identify individuals at higher risk of having contact with TB cases and of developing the disease. The approaches include a routine epidemiological investigation after a new case of TB is notified, where close contacts are identified and specific screening strategies are implemented for recognized individuals that are more vulnerable. However, recent results from the team, based on genetic analysis of Mycobacterium tuberculosis (Mtb) strains from 2014-15, revealed that the ongoing strategies are insufficient. In fact, a longer follow-up is necessary for a comprehensive definition of the transmission chains. In order to do this, 4 years of longitudinal analysis of Mtb strains in Porto will be added to the previous analysis. The Mtb isolates from all confirmed laboratory cases will be genotyped in-house using a certified platform and this genetic characterisation will be complemented with whole genome sequencing for particularly relevant strains. Making use of a novel analytic method, developed by team members, the cases will be integrated in an evolutionary network highlighting characteristics of the cases, such as risk factors. To further improve TB screening strategies a fast and simple diagnostic method will be developed based on mass spectrometry with a portable apparatus to detect TB using urine. To ameliorate the identification of individuals that are at higher risk, and that should follow specific screening programs, immunological markers of increased vulnerability will be investigated using mass cytometry in close collaboration with the Karolinska Institutet (KI), Sweden. This work will be conducted by a multidisciplinary team and aims to generate data on three pivotal aspects to improve current TB control strategies in Porto: 1) complete understanding of TB transmission chains; 2) determination of the exact role of the more vulnerable groups in active transmission and 3) improved diagnostic methods and susceptibility markers for early TB diagnosis and screening. The genetic (ICVS members) and the epidemiologic data (ISPUP) will be combined, using the bioinformatic platform developed by team members (ICVS) to dissect the transmission chains and the role of the more vulnerable groups. This will be complemented with the advances on the diagnostic method (CBQF member) and immunologic markers of increased susceptibility (ICVS and KI). Public health specialists (ISPUP members) will integrate all this information to suggest tuned strategies for TB control in Porto and potentially in other cities in Portugal and other urban areas in Europe.