Since the introduction of antibiotics in the 1930s, illness and death from infectious diseases have declined tremendously. As an example, estimates using historical data suggest a number needed to treat (NNT) of 5 for saving a life in patients with community acquired pneumonia. This shows that antibiotics are of vital importance for human health care. As a result, the management of infections is an issue in many healthcare settings. Severe infections are most prevalent and antibiotic use is most abundant in intensive care units (ICUs) where on average 70% of patients receive an antibiotic (1). These circumstances demand that intensivists have a profound and up-to-date knowledge of all aspects of infection management in critically ill patients. This includes familiarity with diagnostic strategies, criteria on when and how to start antibiotic treatment, how to assure that the right dose is given and when to de-escalate and stop antimicrobial therapy when it is not necessary anymore (2).

Generally speaking, the extensive and often inappropriate use of antibiotics inevitably leads to the development of microorganisms resistant to those antibiotics. The rates of resistance are quite variable in different regions of the world. The website of the “European Centre for Disease Prevention and Control” (ECDC) offers an insight into the distribution of multiresistance in Europe (https://www.ecdc.europa.eu/en). Furthermore, local resistance data on the level of individual hospitals are usually available to clinicians and have an influence on the choice of antibiotics in empirical therapy.

An increase in the prevalence of resistant bacteria is problematic, as antibiotics lose their effectiveness and the number of effective substances declines progressively. One solution to this problem has always been to develop new antibiotics to treat resistant microorganisms but lately the antibiotic pipeline is ‘running dry’. Only a few new classes of antibiotics have emerged in the past decades. Alternatively, in order to curb antibiotic resistance, a decrease of (inappropriate) antibiotic use is essential.

Unfortunately, over-treatment is common in critically ill patients and as much as half of the antibiotics prescribed to patients in the ICU have been estimated to be suboptimal. This can be due to several reasons, e.g. antibiotics are started in a patient without clear signs of infection, prescription of more than one antibiotic when combination therapy is not necessary or a duration of treatment that is unnecessarily long. In addition to high levels of antibiotic use, multiple facilitators for the development of resistance are present in the ICU setting, including loss of physiological barriers and a high transmission risk.