Resumo

MARTIN N, G. Resistencia Bacteriana a ß-lactámicos: Evolución y Mecanismos. AVFT [online]. 2002, vol.21, n.1, pp.107-116. ISSN 0798-0264.

Bacterial infection control starts in the second half of the xxth century and bacterial response has been the development of resistance to the antimicrobial agents used. S.aureus was the first to show resistance to penicillin very soon after the beginning of its use. Bacterial resistance has worldwide distribution and motivated the introduction of new antibiotics. At present, there are few new antimicrobial agents in process of clinical evaluation, b-lactams were the first used antibiotics and they remain the most frequently used for the treatment of infections in hospitals and the community and the most frequent mechanism of resistance is through chromosomal or plasmid transmission b-lactamase production. We discuss the bacterial genetic determinants of resistance and their mechanisms as follow: 1) Changes in the receptor binding capacity: penicillin binding proteins (PBP). 2) Alterations of the mechanisms of entry to the bacterial cell of the antimicrobial agent. 3) Production of inactivating enzymes (b-lactamases). This mechanism is present in both grampositive and gramnegative bacteria, but is most common in the latter. b-lactamases have been classified according to different criteria and the most updated is the functional based named Bush-Jacoby-Medeiros. In order to overcome this type of resistance there have been produced inhibitors such as clavulanic acid, sulbactam and tazobactam. These inhibitors are not effective in all cases because they are unable to inhibit all types of bacterial b-lactamases.

Palavras-chave : Mechanism of resistance; ß -lactams; ß -lactamases; ß-lactamases inhibitors; Efflux pumps; Surveillance resistance program..