COMPETITION OF BETA-LACTAM ANTIBIOTICS FOR THE PENICILLIN-BINDING PROTEINS OF PSEUDOMONAS-AERUGINOSA, ENTEROBACTER-CLOACAE, KLEBSIELLA-AEROGENES, PROTEUS-RETTGERI, AND ESCHERICHIA-COLI - COMPARISON WITH ANTIBACTERIAL ACTIVITY AND EFFECTS UPON BACTERIAL MORPHOLOGY

The competition of a number of β-lactam morphogenic probes for the penicillin-binding proteins (PBSs) of Pseudomonas aeruginosa. Enterobacter cloacae, Klebsiella aerogenes, Proteus rettgeri, and E. coli has been studied. The results indicate that the various gram-negative bacteria have similar, but not identical, PBP patterns and that the individual proteins probably perform similar morphogenic functions as in E. coli K-12. Comparison of the 50% binding concentrations of the compounds for the various PBPs of the five strains with their antibacterial activity indicates that the different antibiotics are excluded to a greater or lesser degree by the outer membrane permeability barrier and that the exclusion is most pronounced in P. aeruginosa.