Na+-driven multidrug efflux pump VcmA from Vibrio cholerae non-O1, a non-halophilic bacterium

FEMS Microbiol Lett. 2001 Sep 25;203(2):235-9. doi: 10.1111/j.1574-6968.2001.tb10847.x.


A chromosomal DNA fragment from Vibrio cholerae non-O1 containing a drug resistance determinant was cloned and sequenced. The deduced amino acid sequence suggested that the determinant gene encodes a multidrug efflux pump. We designated the pump VcmA. Escherichia coli cells transformed with a plasmid carrying the vcmA gene showed increased resistance against norfloxacin, ciprofloxacin, ofloxacin, daunomycin, doxorubicin, streptomycin, kanamycin, ethidium bromide, 4',6-diamidino-2-phenylindole dihydrochloride, Hoechst 33342 and acriflavine. Na+ (or Li+)-dependent efflux of ethidium bromide was detected in transformant cells. Efflux of Na+, elicited by ethidium bromide, was observed from transformant cells. Thus, we concluded that the VcmA is a Na+/drug antiporter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism*
  • Cloning, Molecular
  • Drug Resistance, Multiple, Bacterial / genetics
  • Ethidium / metabolism
  • Genes, Bacterial
  • Membrane Transport Proteins*
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Sequence Analysis, DNA
  • Sodium / metabolism*
  • Vibrio cholerae / drug effects*
  • Vibrio cholerae / genetics*
  • Vibrio cholerae / metabolism


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Carrier Proteins
  • Membrane Transport Proteins
  • VcmA protein, Vibrio cholerae
  • Sodium
  • Ethidium

Associated data

  • GENBANK/AB063193