Mecanismos de resistencia a antibióticos β-lactámicos en Staphylococcus aureus

s. aureus has shown a great power of adaptation to antimicrobial agents, acquiring, step-by-step, resistance to all available antibiotics for treatment of the infections it causes. s. aureus has three major mechanisms of resistance to β-lactam antibiotics: enzyme mediated (penicillinase or β-lactamase) by which the antibiotic is inactivated; intrinsic resistance, which is not due to drug inactivation and accounts for methicillin resistance; and modifications of penicillin-binding proteins (pbps). additionally, s. aureus can express the tolerance phenomenon, in which there is a dissociation of the inhibitory and killing actions of a-lactam antibiotics. of these, the most important mechanism is intrinsic resistance, which is probably more complex because several factors can affect its expression.