Role of AcrAB-TolC multidrug efflux pump in drug-resistance acquisition by plasmid transfer

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Science  24 May 2019:
Vol. 364, Issue 6442, pp. 778-782
DOI: 10.1126/science.aav6390

A race against time

Clinically relevant antimicrobial resistance is largely spread via plasmids that disperse among bacteria during conjugation. How quickly can a resistance gene be expressed after transfer? In susceptible bacterial cells, tetracycline should inhibit protein synthesis, including from the plasmid-transferred resistance gene tetA. Unexpectedly, Nolivos et al. found that TetA can be expressed despite the presence of tetracycline (see the Perspective by Povolo and Ackermann). Immediately after plasmid transfer into a cell, TetA synthesis starts because its repressor is slow to be expressed. In addition, the ubiquitous xenobiotic efflux pump AcrAB-TolC buys time for TetA translation by keeping tetracycline concentration below toxic levels.

Science, this issue p. 778; see also p. 737