The surfaces of the human body host colonies of microorganisms, known as microbiomes. Along with bacteria which have a positive effect on human health, microbiomes contain potentially life-threatening pathogens. In the past, broad-spectrum antibiotics have often been used to tackle them. Nowadays it is known that this not only promotes resistance to antibiotics – in many cases it also damages the microbiome as a whole. A worldwide increase in antibiotic-resistant bacterial pathogens (ARBPs), coupled with declining discoveries of novel classes of antibiotics, raises the specter of a post-antibiotic era. Preventing the spread, human colonization, and subsequent infection by ARBPs is essential in preserving fundamental medical achievements of the 20th century. A paradigm shift in infection control is needed, putting a hold to the indiscriminate use of antibiotics and enabling the development of targeted anti-infective strategies that promote microbiome integrity. The researchers of the Cluster of Excellence "Controlling Microbes to Fight Infections" (CMFI) at the University of Tübingen aim to elucidate the mechanisms of interaction between beneficial and harmful bacteria in order to make them useful for targeted therapeutic interventions.