Infections are specifically deleterious when the immune system of the host is compromised by iatrogenic intervention or as a result of an infectious agent, such as HIV. In principle, there are three strategies to improve the clinical situation: i) to develop better antibiotic treatment (targeting the microbe), and ii) to improve the immune status of the patient (targeting the host), and iii) to better use existing therapies. In all three areas the BonnCologne Center for Infectious Diseases (BC-CID) has outstanding expertise as exemplified by DFG-funded joint grants: FOR 854 which identifies antibiotic lead structures for new anti-infectives, and CRC670 which studies host factors in cell-autonomous immunity. These two research areas are linked to core units for high-throughput screenings, deep sequencing, and genome-wide siRNA libraries. Translational strategies include gene therapy and oligonucleotide-based approaches to revert immunosuppression. In clinical research, a board-certified center for infectious diseases provides an ideal infrastructure for training young physicians and for clinical trials. A strong clinical focus is the management of HIV-infected patients (BMBF clinical research group: HIV infection and infections in immunosuppressed patients). Expertise extends to the management of infections in neutropenic patients, as well as the treatment of parasitic infections, and is accompanied by renowned epidemiology. Thus, this consortium bundles the critical mass for a sustained impact on the treatment of infections in the immunocompromised host.