the existence in cultures of p. aeruginosa of variants showing elevated beta-lactamase production may account at least in part for the effect of inoculum size on the activity of azlocillin and piperacillin against p. aeruginosa and the marked discrepancy between mic and minimum bactericidal concentration ( mbc ) which is characteristic of the ureido penicillins .
C0031955
piperacillin
C0030842
penicillins