The group of the Hospital Universitario 12 de Octubre (I + 12) is a multidisciplinary team composed of infectious diseases physicians and clinical microbiologists. Our Group is involved in the two research programs of the network. The main lines of research within the transplant program are: 1) immunoguided strategy for prophylaxis of cytomegalovirus infection (CMV) in renal transplantation, 2) measurement of specific cytotoxic response against CMV, 3) impact of immune status recipient of a solid organ transplant (SOT) on the incidence of infectious complications after transplantation, 4) reactivation of Epstein-Barr virus in SOT recipients as a marker of immunosuppression 5) tuberculosis prophylaxis in liver transplantation, 6) treatment of asymptomatic bacteriuria in renal transplant, 7) influence of the gut microbiome in transplantation. Most projects are aimed at finding an efficient, simple and applicable tool in clinical practice to be able to individually measure the state of immunosuppression for each patient, in order to adopt preventive strategies to avoid the complications associated with immunosuppression. The main lines of research within the program of antimicrobial resistance are: 1) Molecular epidemiology of microorganisms causing hospital infections, mechanisms of antimicrobial resistance and pathogenicity factors, 2) Staphylococcus aureus infections: molecular epidemiology and virulence factors, impact of genotype and phenotype in S. aureus endocarditis and catheter-related bacteremia, 3) implementation of counselling programs and control of antimicrobial therapy in the hospital. Our group has made significant scientific contributions in determining risk factors and molecular mechanisms that facilitate the spread of epidemic clones in the hospital. Overall, the group has published around 150 manuscripts in the last five years, including guidelines on the management of tuberculosis, fungal, and viral infections in SOT patients. Our group is founded by Spanish research agencies and pharmaceutical industry.