The microorganisms can behave as pathogens or commensals against which higher organisms develop defense mechanisms, or as symbionts that benefit their hosts. The complete characterization of the molecular processes that control the life cycle and functions of microorganisms, as well as the molecular mechanisms involved in the regulation of microorganism-host interactions (beneficial for both or harmful for the host), represent a great challenge in biology and biomedicine.

The Molecular Microbiology and Infection Biology (MMIB) Department includes research groups that study the microorganisms (pathogens, commensals or symbionts) and also the leukocytes that either defend or regulate the coexistence with these microorganisms. The department includes research groups studying the molecular biology of Gram-positive bacteria, including DNA replication and expression in bacteria, gene transfer in bacteria, bacterial toxin-antitoxin systems, the biology of parasites such as Leishmania as well as different aspects of the biology of dendritic cells and macrophages. The groups of the MMIB Department include experts in biochemistry, biophysics, immunology, microbiology, molecular and cell biology, physiology, virology, bioinformatics and structural biology. The complementarity among the research groups of the department creates an environment that facilitates the transfer of knowledge and technology and enables studies that require a multidisciplinary approach.