Monday, October 10, 2011


Vancomycin is a glycopeptide antibiotic became available in the mid-1950s. It inhibits synthesis of cell wall peptidoglycan by binding to the C-terminal of the cell wall precursor pentapeptide (Winston and Chambers, 2009).
Vancomycin binds non-covalently to the cell-wall precursors of gram-positive bacteria. Specifically, the binding occurs through a set of five hydrogen bonds between the antibiotic and the D-Ala-D-Ala dipeptide portion of the stem pentapeptides linked to the N-acetylmuramic acid backbone. This binding blocks the cross linking transpeptidase reaction catalyzed by the PBPs. Consequently the cell walls are rendered less rigid and more susceptible to lyses (Jayaraman, 2009).
The lipopolysaccharide outer membrane of gram-negative bacteria renders this target inaccessible to the drug, and thus these organisms are intrinsically resistant (Wright, 2003).

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