[Resistance of gram-negative bacteria to beta-lactams, aminoglycosides and quinolones]

Antibiotic treatment of infections has traditionally been restrictive, in that use of broad-spectrum antibiotics has been avoided as far as possible. A change in therapeutic principles has occurred in recent years for example with respect to treatment of patients that are immunocompromised, suffering from multiple traumas, recovering from major surgery or have implanted foreign bodies. The use of antibiotics has become more complicated, as one more frequently has to consider the possibility of development of antibiotic resistance in different bacterial species because of long-term treatment regimes in such patients. However, it is important to avoid the spread of broad-spectrum antibiotic regimes such as those for neutropenic patients to less vulnerable patient groups, where narrow-spectrum therapy is usually sufficient. In later years an increased resistance to broad-spectrum antibiotics among enterobacteria has been described abroad. Resistance mechanisms for the most commonly used intravenous antibiotics (beta-lactams, aminoglycosides and quinolones) are described. Resistance mechanisms for the individual antibiotics, cross-resistance and the most important epidemiological aspects are discussed. It is suggested that surveillance of antibiotic use and development of resistance as well as identification of resistance mechanisms be increasingly used so as to continuously ensure optimum treatment regimes.