Peptidoglycan Composition of Vancomycin-ResistantEnterococcus faecium

Muropeptide composition of peptidoglycan isolated from isogenic vancomycin-resistant and -sensitive Enterococcus faecium strains was analyzed by reverse-phase high-performance liquid chromatography combined with amino acid and fast atom bombardment mass spectrometric analyses. Peptidoglycan of the sensitive and resistant strains was the same and was composed of tri- and tetrapeptides stem peptide subunits with or without aspartate or asparagine substitutions on the ε-amino group of the lysine residue. Thus, the synthesis of lactate-terminating peptidoglycan precursors in vancomycin-resistant E. faecium did not affect the chemical composition of peptidoglycan.