Six different types of vancomycin resistance are shown by enterococcus : Van-A, Van-B, Van-C, Van-D, Van-E and Van-G.[9] The significance is that Van-A VRE is resistant to both vancomycin and teicoplanin,[10] Van-B VRE is resistant to vancomycin but susceptible to teicoplanin,[11][12] and Van-C is only partly resistant to vancomycin, and susceptible to teicoplanin.
The mechanism of resistance to vancomycin found in enterococcus involves the alteration peptidoglycan synthesis pathway.[13] The D-alanyl-D-lactate variation results in the loss of one hydrogen-bonding interaction (four, as opposed to five for D-alanyl-D-alanine) being possible between vancomycin and the peptide. The D-alanyl-D-serine variation causes a six-fold loss of affinity between vancomycin and the peptide, likely due to steric hindrance