The acquisition of horizontally acquired resistance genes leads to the production of peptidoglycan with D-Ala-D-Lac terminal residues that are insensitive to vancomycin

The altered expression of intrinsic genes leads to the production of a thicker cell wall that reduces the effectiveness of vancomycin

The acquisition of horizontally acquired resistance genes leads to a reduction in overall peptidoglycan production, which reduces the effectiveness of vancomycin

The altered expression of intrinsic genes leads to the production of peptidoglycan with D-Ala-D-Lac terminal residues that reduce the effectiveness of vancomycin