Ketolides lack inducibility properties of MLS(B) resistance phenotype.
Ketolides belong to a new class of semi-synthetic 14-membered-ring macrolides, which differ from erythromycin A by having a 3-keto group instead of the neutral sugar L-cladinose. The ability of these molecules and their L-cladinose counterparts to induce MLS(B) resistance in staphylococci (one strain) and streptococci (two strains) was investigated using a disc agar susceptibility method as well as measuring induction kinetics. All 14- and 15-membered ring macrolides tested showed inducing activity. In contrast, ketolides were clearly unable to induce MLS(B) resistance, a result consistent with the high in-vitro activity of this new class of antibiotics against erythromycin A-inducible resistant bacteria.
Bonnefoy
A
A
Antiinfective Research Department, Roussel UCLAF, Romainville, France.
Girard
A M
AM
Agouridas
C
C
Chantot
J F
JF
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000494:pharmacology; D048628:Ketolides; D007700:Kinetics; D018942:Macrolides; D008826:Microbial Sensitivity Tests / Q000379:methods; D010641:Phenotype; D013211:Staphylococcus aureus / Q000187:drug effects*; D013291:Streptococcus / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D048628:Ketolides; D018942:Macrolides; C105420:RU 64004; D004917:Erythromycin