Efflux in cooperation with other resistance mechanisms

Contributions of the AmpC b-lactamase and the AcrAB Multidrug Efflux System in Intrinsic Resistance of E. coli to b -lactams

Mazzariol et al, AAC (2000) 44:1387-1390

Efflux b-lactamase MIC carbenicillin

- - 0.2

+ - 12.5

+++ - 50

- + 100

+ + 200

+++ + 400

Intrinsic low level

resistance !

high level

resistance !