Functional genomic analyses of multidrug efflux pumps in Acinetobacter baumannii
Acinetobacter baumannii is a tenacious Gram-negative opportunistic human pathogen, which has become a serious problem in hospital settings, due largely to its high level of drug resistance, and virulence potential. Bioinformatic analyses using the Transporter Automatic Annotation Pipeline (www.membranetransport.org), maintained by our research group, have identified an abundance of putative multidrug efflux systems in A. baumannii strains. Multidrug efflux pumps have important roles in drug resistance and virulence in a number of Gram-negative pathogens, yet the functional roles of most putative efflux pumps in A. baumannii have not been described. We have undertaken multifaceted global analyses to determine whether the putative efflux pumps are likely to contribute to antimicrobial resistance A. baumannii. Through these analyses we have identified several pumps that mediate the efflux of drugs, including a new family of multidrug efflux pumps, as well as pumps that maintain stable cellular physiology, such as metal ion homeostasis systems. This short talk will focus on our recent work using transposon directed insertion site sequencing to investigate the antimicrobial transport activities of efflux pumps in A. baumannii.