RESUMEN
BACKGROUND: Nosocomial pneumonia is among the most common types of infection in hospitalized patients. The increasing prevalence of multi-drug resistant organisms (MDROs) in recent years points to the need for an up-to-date clinical guideline. METHODS: An interdisciplinary S3 guideline was created on the basis of a systematic literature review in the PubMed and Cochrane Library databases, with assessment and grading of the evidence according to the GRADE system. RESULTS: 9097 abstracts and 808 articles were screened in full text, and 22 recommendations were issued. It is recommended that any antimicrobial treatment should be preceded by a microbiological diagnostic evaluation with cultures of blood and respiratory samples. The diagnosis of nosocomial pneumonia should be suspected in any patient with a new or worsened pulmonary infiltrate who meets any two of the following three criteria: leucocyte count above 10,000 or below 4000/µL, temperature above 38.3°C, and/or the presence of purulent respiratory secretions. The initially calculated antimicrobial treatment should be begun without delay; it should be oriented to the locally prevailing resistance pattern, and its intensity should be a function of the risk of infection with MDROs. The initial treatment should be combination therapy if there is a high risk of MDRO infection and/or if the patient is in septic shock. In the new guideline, emphasis is laid on a strict de-escalation concept. In particular, antimicrobial treatment usually should not be continued for longer than eight days. CONCLUSION: The new guideline's recommendations are intended to encourage rational use of antibiotics, so that antimicrobial treatment will be highly effective while the unnecessary selection of multi-drug-resistant organisms will be avoided.