Investigating the regulation and function of bacterial quaternary ammonium compound exporters.

Abstract

Quaternary ammonium cations were introduced as commonly used disinfectant compounds in the 1930s. Today, they are often used in disinfectant solutions and wipes. Bacterial resistance to these antiseptic compounds is mediated by transporters from the small multidrug resistance (SMR) family of proteins. SMR transporters are bacterial proton-coupled transporters that export cationic substrates including quaternary ammonium compounds. Here we examine the genetic regulation of SMR expression. In addition, we use solid supported membrane (SSM) electrophysiology to observe transport of quaternary ammonium compounds by purified, reconstituted QacE proteins. Our findings allow us to functionally characterize and obtain insight into the evolution of these quaternary ammonium antiseptic transporters so that we can further investigate how to mitigate the spread of antiseptic resistance among bacterial populations.