Increased susceptibility to cephamycin-type antibiotics of methicillin-resistant Staphylococcus aureus defective in penicillin-binding protein 2.

A methicillin-resistant strain of Staphylococcus aureus which produced low-affinity penicillin-binding protein 2' (PBP 2') spontaneously lost PBP 2 when the strain was cultivated at 43 degrees C overnight. At 37 degrees C, the mutant had increased susceptibility to cephamycin-type beta-lactams, which showed high affinity for PBP 4. This result suggests that inhibition of PBP 4, in addition to that of PBP 2, is necessary to kill methicillin-resistant strains.