ALTERED PEPTIDOGLYCAN COMPOSITION IN VANCOMYCIN-RESISTANT ENTEROCOCCUS-FAECALIS

The muropeptide compositions of isogenic vancomycin-resistant and -sus ceptible Enterococcus faecalis strains were analyzed by reverse-phase high-performance liquid chromatography combined with amino acid analys is and fast atom bombardment mass spectrometry, Peptidoglycan of the s usceptible strain contained pentapeptides as stem peptides, whereas pe ptidoglycan of the isogenic resistant strain was composed of muropepti des with tetrapeptide stem peptides. Despite the synthesis of lactate- terminating peptidoglycan precursors, no lactate-containing muropeptid es were detected In peptidoglycan of the resistant strain. These findi ngs indicate that either lactate-terminating precursors are not incorp orated into peptidoglycan of the resistant strain or that the lactate residues are removed from peptidoglycan during synthesis.