N. Masuda et al., Interplay between chromosomal beta-lactamase and the MexAB-OprM efflux system in intrinsic resistance to beta-lactams in Pseudomonas aeruginosa, ANTIM AG CH, 43(2), 1999, pp. 400-402
We investigated the role of chromosomal beta-lactamase and the MexAB-OprM e
fflux system in intrinsic resistance to beta-lactams in Pseudomonas aerugin
osa. Determination of the susceptibilities of a series of isogenic mutants
with impaired production of the beta-lactamase and the efflux system to 16
beta-lactams including penicillins, cephems, oxacephems, carbapenems, and a
monobactam demonstrated that the intrinsic resistance of P. aeruginosa to
most of the beta-lactams is due to the interplay of both factors.