[Classification and diagnostics of multiresistant bacteria].

Multidrug-resistant organisms are spreading worldwide. Chromosomally encoded resistance mechanisms are spread by clonal expansion, e.g., methicillin-resistant Staphylococcus aureus strains. Plasmid-encoded mechanisms such as extended-spectrum beta-lactamases spread even more efficiently because they can also be horizontally transferred into other species. Acquisition of additional resistance genes minimizes therapeutic options and leads to frequent treatment failure. Laboratory diagnostics is laborious and time-consuming and requires combinations of different phenotypic and molecular methods. Increasing knowledge of treatment and diagnostics is essential for physicians.