Gram-negative pathogens especially may deploy an arsenal of efflux pumps to protect and modulate their internal milieu. Many of these pumps collectively and/or individually can pump out antibiotics thereby making species either intrinsically or prone to develop increasingly levels of resistance to different classes of antibiotics.. As one example, notoriously drug resistance Burkholderia species may contain over a dozen so-called tripartite, root nodulation division (RND) efflux pumps (PMC1557404).
In our profiling of novel antibiotics, we have also sought to examine how alteration of antibiotic structure may contribute to efflux efficiency. In the process, we have cloned efflux system components and established experiment systems for quantifying efflux using microbiological measurements.