Beta-lactamases: current situation and clinical importance.
Production of beta-lactamases is the most important means of bacterial resistance to beta-lactam antibiotics. The traditional, plasmid-mediated beta-lactamases were initially confined to Enterobacteriaceae but have now spread to other genera and species including Pseudomonas aeruginosa, Haemophilus influenzae, and Neisseria gonorrhoeae. Extended-spectrum plasmid-mediated beta-lactamases have been identified in Enterobacteriaceae, particularly Klebsiella spp. and Escherichia coli. They are capable of hydrolyzing second- and third-generation cephalosporins and older beta-lactams. Chromosomally mediated beta-lactamases may be produced constitutively or induced by the presence of a beta-lactam. Mutation within the bacterial genome may lead to constitutive enzyme hyperproduction. Strains that produce these enzymes are resistant to practically all beta-lactams, with the exception of carbapenems. The wide-spread occurrence of antibiotic resistance dictates that therapies be judiciously chosen with attention to the resistance patterns of the causative organisms.
Garau
J
J
Hospital de Mutua de Terrassa, Barcelona, Spain.
D000900:Anti-Bacterial Agents / Q000037:antagonists & inhibitors; D004352:Drug Resistance, Microbial; D004790:Enzyme Induction / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000201:enzymology; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D010957:Plasmids; D001618:beta-Lactamases / Q000096:biosynthesis / Q000145:classification / Q000494:pharmacology*; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases