Infections play an important role in childhood and the interplay between the developing immune system and different microorganisms is paradigmatic for a better understanding of host-pathogen interactions. Broad-spectrum antibiotic treatments lead to the development and spread of antimicrobial resistances and antibiotic stewardship (ABS) programs are the most effective countermeasure. Our group has developed guidelines and computer programs to promote ABS in hospitalized children, and we are currently evaluating AI-supported treatment regimen. We still do not have useful vaccinations against multi-resistant nosocomial pathogens and therefore our group has identified several proteins, polysaccharides and monoclonal antibodies against these antigens that could be used to treat and/or prevent infections due to gram-positive bacteria, such as enterococci, staphylococci, and streptococci.