Increased expression of the multidrug efflux genes acrAB occurs during slow growth of Escherichia coli.

Intrinsic antimicrobial resistance of Escherichia coli is elicited by the gene products of the multidrug efflux acrAB-tolC operon. In this paper, we have shown that acrAB is regulated as a function of the growth rate of E. coli during growth in batch and chemostat culture.