Characterising the novel efflux pump, EefABC, of Escherichia coli.

Burgess, Leah (2025). Characterising the novel efflux pump, EefABC, of Escherichia coli. University of Birmingham. M.Sc.

Burgess2025MScbyRes.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (2MB)

Abstract

Gram-negative bacteria, such as Escherichia coli, contain RND efflux pumps that form tripartite efflux pumps which span the inner and outer membrane. A seventh RND pump, EefB, was identified prior to this study by the Blair lab at the University of Birmingham, in addition to the six known RND pumps of E. coli; AcrB, AcrD, AcrF, MdtBC, MdtF and CusA. The gene for the seventh RND pump is located on a five-gene locus, eefRABCD, which encodes a TetR regulator (EefR), a periplasmic adaptor protein (EefA), an inner membrane RND pump (EefB), an outer membrane protein (EefC) and a major facilitator superfamily transporter (EefD). EefB forms a tripartite efflux pump, EefABC, which is highly conserved across E. coli phylogroups commonly associated with infection. Experimental techniques utilising loss and gain of EefABC function strains show that the pump is functional and able to transport toxic dyes ethidium bromide and rhodamine-6G, and that overexpression increases fatality of infected Galleria mellonella. Unlike common RND efflux pump complexes, such as AcrAB-TolC, there is no evidence to suggest that EefABC confers antimicrobial resistance in E. coli. Metabolomic analysis of the exometabolome reveals the mass of three potential substrates of EefABC, though further work is necessary for the assignment of these to known molecules. Overall, my findings present EefABC as a functional RND efflux complex which can increase the infection potential of E. coli.

Type of Work:

Thesis (Masters by Research > M.Sc.)

Award Type:

Masters by Research > M.Sc.

Supervisor(s):