Because the development of resistance is steadily increasing, especially among Gram-negative pathogens and new developments in antibiotics are lacking, a rational antibiotic therapy is necessary now more than ever. A continuing uncritical and non-guideline-conform use of antibiotics leads to selection of multidrug-resistant pathogens, which can colonize patients and as instigators of infections make treatment more difficult. A prerequisite for targeted antibiotic therapy is a critical testing of the suspected infection diagnosis based on a guideline-conform microbiological preanalytical procedure. To promote a guideline-conform antibiotic therapy in hospitals with respect to choice of substance, dosage and duration, in December 2013 so-called antibiotic stewardship (ABS) measures were summarized in a so-called S3-guideline from the Association of the Scientific Medical Societies in Germany (AWMF) under the auspices of the German Society for Infectious Diseases (DGI). With a strategy of targeted antibiotic therapy and infection prevention it is possible to achieve optimum treatment results and to minimize the development of resistance.