Activity of cefsulodin and other agents against Pseudomonas aeruginosa.

Cefsulodin is a novel cephalosporin that contains a pyridinomethyl substituent at position 3 of the dihydrothiazine ring and a sulfo group on the acyl side chain. Cefsulodin has a high affinity for penicillin-binding proteins of Pseudomonas aeruginosa but binds poorly to those of other bacteria. Cefsulodin has the ability to readily pass through the outer wall of P. aeruginosa and is poorly hydrolyzed by most chromosomal beta-lactamases. It is partially destroyed by the carbenicillinases of P. aeruginosa that are plasmid mediated. Cefsulodin inhibits 50% of P. aeruginosa isolates at concentrations of 2-4 micrograms/ml. Cefsulodin acts synergistically with all aminoglycosides against 20%-80% of P. aeruginosa isolates.