[Mechanism of action of beta-lactam antibiotics and problems concerning the development of resistance in antibacterial chemotherapy].
Beta-lactam antibiotics influence the metabolism of bacteria in very low concentrations by blocking the activity of penicillin binding proteins of gram-negative rods. Dependent on the type of binding protein affected bacteria form filaments or sphaeroblasts. The most important resistance mechanism is the formation of beta lactamases, which cleave the beta-lactam ring and inactivate the antimicrobially active molecule. Gram-positive bacteria like Staphylococci excrete the enzymes into the environment; as long as the antibiotic is not destroyed by the enzyme, activity antimicrobial effectiveness is present and prevents bacterial proliferation. In gram-negative bacteria the beta lactamases are formed in the periplasmic space and inactivate the antibiotic after penetration into the bacterial organism. This type of beta-lactamase formation is transferred to the organism by transduction, transformation or conjugation. Bacterial resistance against beta-lactam antibiotics need not only be due to inactivation of the antimicrobial substance by beta lactamases, but can also be due to mechanisms independent of enzyme activity. We call this intrinsic resistance. Prior to clinical application of beta-lactam antibiotics the susceptibility of the organism should be determined by an antibiogram.
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial; D006090:Gram-Negative Bacteria / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D014161:Transduction, Genetic; D014169:Transformation, Bacterial; D001618:beta-Lactamases / Q000378:metabolism; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases
Wirkungsmechanismus der Betalaktamantibiotika und Probleme der Resistenzentwicklung bei der antibakteriellen Chemotherapie.