Glycopeptide
A class of peptide antibiotics containing sugar groups, working by binding to bacterial cell wall precursors. Vancomycin is the archetypal glycopeptide and a cornerstone of hospital antibiotic therapy. Telavancin, dalbavancin, and oritavancin are newer lipoglycopeptides with enhanced properties.
Technical Context
Glycopeptide mechanism: the peptide backbone forms 5 hydrogen bonds with the D-Ala-D-Ala terminus of peptidoglycan precursors (lipid II), physically blocking transglycosylation and transpeptidation steps of cell wall synthesis. Vancomycin resistance (VRE): bacteria modify the target to D-Ala-D-Lac, reducing binding affinity 1000-fold. The vanA and vanB gene clusters encode resistance enzymes. Newer glycopeptides address resistance partially: telavancin has additional membrane depolarisation activity; dalbavancin and oritavancin have enhanced lipophilic side chains enabling membrane anchoring and dimerisation, increasing binding avidity and providing activity against some VanB-type VRE. Dalbavancin's ultra-long half-life (~346 hours) enables single-dose or two-dose treatment of skin infections — the longest dosing interval of any approved antibiotic.