DETECTION OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS (MRSA) WITH ANTIBODIES AGAINST SYNTHETIC PEPTIDES DERIVED FROM PENICILLIN-BINDING PROTEIN-2'

Ten kinds of peptides (21 to 32 amino acids in length) were synthesize d based on the reported amino acid sequences of the penicillin-binding protein 2' (PBP2') of methicillin-resistant Staphylococcus aureus (MR SA). Antibodies against these synthetic peptides (SPs) were generated by immunizing rabbits. The antibodies raised against all the peptides except for one reacted to PBP2' of MRSA and to SPs used for immunizati on but not to any other protein of MRSA or methicillin-susceptible S. aureus (MSSA) tested by ELISA and Western blotting. A sandwich immunor adiometric assay (IRMA) for the detection of PBP2' was developed using these antibodies. The method could detect PBP2' extracted from as few as 3 x 10(4) cells of a clinical MRSA isolate, and a good correlation between cell number and signal radio-count was observed. IRMA was pos itive for all 51 methicillin-resistant staphylococci isolated from pat ients, and was negative for all the 28 methicillin-susceptible ones an d 19 strains of other bacterial species. IRMA could be a simple and re liable method for MRSA detection in the clinical bacterial laboratory.