Selective lysis of cultures and cell walls of penicillin-resistant but not penicillin-susceptible Streptococcus pneumoniae strains by a murein hydrolase complex.

A murein hydrolase complex selectively lysed cultures of penicillin-resistant pneumococci and their cell walls in which the majority of muropeptide subunits were indirectly cross-linked through oligopeptide substituents (alanyl-alanine or alanyl-serine) on the epsilon-amino group of the stem peptide lysine residues. Walls of penicillin-susceptible strains were not hydrolyzed.