title: [Macrolides, ketolides and streptogramins].
abstract: Macrolides, ketolides and streptogramins are three families of antibiotics with different chemical structures, sharing the same mechanism of action. All three bind to distinct bases of the peptidyl transferase center of ARNr 23S. Their antibacterial spectrum practically overlaps, but dissimilarities in affinity and/or number of binding sites determine differences in the intensity of their antibacterial effects (bacteriostatic or bactericidae) and in their activity against strains with acquired resistance mechanisms. These agents are active against the majority of gram-positive microorganisms and many intracellular microorganisms for growth. Over the last five years in our country, the percentage of macrolide-resistant pneumococci and S. pyogenes strains has increased substantially. Telithromycin (ketolide) and Synercid (streptogramin) have shown maintained activity against these strains. Macrolides, ketolides and streptogramins are metabolized in the liver through CYP 3A4 and they can partially block the activity of the enzyme, interfering with the metabolism of other drugs that use the same metabolic pathway. There is little elimination through the urine, with the exception of clarithromycin. High concentrations are reached in the cellular cytoplasm, but they do not diffuse to the CSF. These agents are included among class B drugs for use during pregnancy. Tolerance to macrolides and telithromycin is good and they have few associated adverse effects. The main clinical indication for these drugs is in empirical treatment of mild to moderate, community-acquired, upper and lower respiratory tract infections. Synercid is indicated in the treatment of infections due to methicillin-resistant staphylococci and glycopeptide-resistant enterococci.
authors.affiliation: Instituto Clínico de Infecciones e Inmunología. Hospital Clínic. Barcelona. España. jmensa@clinic.ub.es
authors.forename: José
authors.initials: J
authors.lastname: Mensa
authors.forename: Elisa
authors.initials: E
authors.lastname: García-Vázquez
authors.forename: Jordi
authors.initials: J
authors.lastname: Vila
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000737:chemistry / Q000145:classification / Q000494:pharmacology / Q000627:therapeutic use; D001711:Biotransformation; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004347:Drug Interactions; D004351:Drug Resistance; D005767:Gastrointestinal Diseases / Q000139:chemically induced; D006090:Gram-Negative Bacteria / Q000187:drug effects; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy; D006094:Gram-Positive Bacteria / Q000187:drug effects; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy; D006319:Hearing Loss, Sensorineural / Q000139:chemically induced; D006801:Humans; D048628:Ketolides; D018942:Macrolides; D008862:Microsomes, Liver / Q000201:enzymology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D012329:RNA, Bacterial / Q000187:drug effects; D012338:RNA, Ribosomal, 23S / Q000187:drug effects; D025361:Streptogramins / Q000009:adverse effects / Q000737:chemistry / Q000145:classification / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D048628:Ketolides; D018942:Macrolides; D011500:Protein Synthesis Inhibitors; D012329:RNA, Bacterial; D012338:RNA, Ribosomal, 23S; D025361:Streptogramins; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C106791:telithromycin