THE ROLE OF PENICILLIN-BINDING PROTEIN-3 (PBP-3) IN CEFOTAXIME RESISTANCE IN STREPTOCOCCUS-PNEUMONIAE

A pneumococcal strain, with a reduced amount of penicillin-binding pro tein 3 (PBP 3), permitted an analysis of the role of this protein in c efotaxime resistance. We observed that reduced amounts of PBP 3 sensit ize the bacteria to high temperature, to excess glycine and to some D- amino acids. These phenotypes suggest that the amount of PBP 3 may inf luence the membrane properties of the bacteria. The strain with reduce d PBP 3 was transformed to cefotaxime resistance. We show that the PBP 3 mutation, in certain genetic backgrounds, decreases the level of re sistance to cefotaxime by a factor of 2. Models are presented to expla in this result.