| Title | Functional analysis of Vibrio vulnificus RND efflux pumps homologous to Vibrio cholerae VexAB and VexCD, and to Escherichia coli AcrAB |
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| Author | Seunghwa Lee1†, Ji-Hyun Yeom1†, Sojin Seo1, Minho Lee1, Sarang Kim2, Jeehyeon Bae2*, Kangseok Lee1*, and Jihwan Hwang3* |
| Address | 1Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea, 2College of Pharmacy, Chung-Ang University, Seoul 156-756, Republic of Korea, 3Department of Microbiology, Pusan National University, Busan 609-735, Republic of Korea |
| Bibliography | Journal of Microbiology, 53(4),256-261, 2015, |
| DOI | 10.1007/s12275-015-5037-0 |
| Key Words | AcrAB, multidrug resistance, resistance-nodulation-division, VexAB, VexCD |
| Abstract | Resistance-nodulation-division (RND) efflux pumps are associated with multidrug resistance in many gram-negative pathogens. The genome of Vibrio vulnificus encodes 11 putative RND pumps homologous to those of Vibrio cholerae and Escherichia coli. In this study, we analyzed three putative RND efflux pumps, showing homology to V. cholerae VexAB and VexCD and to E. coli AcrAB, for their functional roles in multidrug resistance of V. vulnificus. Deletion of the vexAB homolog resulted in increased susceptibility of V. vulnificus to bile acid, acriflavine, ethidium bromide, and erythromycin, whereas deletion of acrAB homologs rendered V. vulnificus more susceptible to acriflavine only. Deletion of vexCD had no effect on susceptibility of V. vulnificus to these chemicals. Upon exposure to these antibacterial chemicals, expression of tolCV1 and tolCV2, which are putative outer membrane factors of RND efflux pumps, was induced, whereas expression levels of vexAB, vexCD, and acrAB homologs were not significantly changed. Our results show that the V. vulnificus homologs of VexAB largely contributed to in vitro antimicrobial resistance with a broad substrate specificity that was partially redundant with the AcrAB pump homologs. |