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The AraC-family regulator GadX enhances multidrug resistance in Escherichia coli by activating expression of mdtEF multidrug efflux genes

  • Original Article
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Journal of Infection and Chemotherapy

Abstract

Multidrug efflux pumps contribute to the resistance of Escherichia coli to many antibiotics and biocides. Here, we report that the AraC-family regulator GadX increases multidrug resistance in E. coli through activation of the MdtEF efflux pump. Screening of random fragments of genomic DNA for ability to increase β-lactam resistance led to the isolation of a plasmid containing gadX, which codes for the regulator of acid resistance. When overexpressed, gadX significantly increased the resistance of the E. coli strain to oxacillin, cloxacillin, nafcillin, erythromycin, rhodamine 6G, and sodium dodecyl sulfate. The increase in drug resistance caused by gadX overexpression was completely suppressed by deleting the multifunctional outer membrane channel gene tolC. TolC interacts with different drug efflux pumps. Quantitative real-time polymerase chain reaction (PCR) showed that GadX activated the expression of mdtEF but none of the other drug efflux pumps in E. coli. Deletion of mdtEF completely suppressed GadX-mediated multidrug resistance. Our results indicate that the GadX regulator, in addition to its role in acid resistance, increases multidrug resistance in E. coli by activating the MdtEF multidrug efflux pump.

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References

  1. Nikaido H. Multidrug efflux pumps of gram-negative bacteria. J Bacteriol 1996;178:5853–5859.

    PubMed  CAS  Google Scholar 

  2. Zgurskaya HI, Nikaido H. Multidrug resistance mechanisms: drug efflux across two membranes. Mol Microbiol 2000;37:219–25.

    Article  PubMed  CAS  Google Scholar 

  3. Putman M, van Veen HW, Konings WN. Molecular properties of bacterial multidrug transporters. Microbiol Mol Biol Rev 2000;64:672–693.

    Article  PubMed  CAS  Google Scholar 

  4. Brown MH, Paulsen IT, Skurray RA. The multidrug efflux protein NorM is a prototype of a new family of transporters. Mol Microbiol 1999;31:394–395.

    Article  PubMed  CAS  Google Scholar 

  5. Paulsen IT, Chen J, Nelson KE, Saier MH. Comparative genomics of microbial drug efflux systems. J Mol Microbiol Biotechnol 2001;3:145–150.

    PubMed  CAS  Google Scholar 

  6. Murakami S, Nakashima R, Yamashita E, Yamaguchi A. Crystal structure of bacterial multidrug efflux transporter AcrB. Nature 2002;419:587–593.

    Article  PubMed  CAS  Google Scholar 

  7. Yu EW, Aires JR, Nikaido H. AcrB multidrug efflux pump of Escherichia coli: composite substrate-binding cavity of exceptional flexibility generates its extremely wide substrate specificity. J Bacteriol 2003;185:5657–5664.

    Article  PubMed  CAS  Google Scholar 

  8. Murakami S, Nakashima R, Yamashita E, Matsumoto T, Yamaguchi A. Crystal structures of a multidrug transporter reveal a functionally rotating mechanism. Nature 2006;443:173–179.

    Article  PubMed  CAS  Google Scholar 

  9. Nishino K, Yamaguchi A. Analysis of a complete library of putative drug transporter genes in Escherichia coli. J Bacteriol 2001;183:5803–5812.

    Article  PubMed  CAS  Google Scholar 

  10. Ma D, Cook DN, Hearst JE, Nikaido H. Efflux pumps and drug resistance in gram-negative bacteria. Trends Microbiol 1994;2:489–493.

    Article  PubMed  CAS  Google Scholar 

  11. Nikaido H. Prevention of drug access to bacterial targets: permeability barriers and active efflux. Science 1994;264:382–388.

    Article  PubMed  CAS  Google Scholar 

  12. Nishino K, Yamada J, Hirakawa H, Hirata T, Yamaguchi A. Roles of TolC-dependent multidrug transporters of Escherichia coli in resistance to β-lactams. Antimicrob Agents Chemother 2003;47:3030–3033.

    Article  PubMed  CAS  Google Scholar 

  13. Elkins CA, Nikaido H. Substrate specificity of the RND-type multidrug efflux pumps AcrB and AcrD of Escherichia coli is determined predominantly by two large periplasmic loops. J Bacteriol 2002;184:6490–6498.

    Article  PubMed  CAS  Google Scholar 

  14. Fralick JA. Evidence that TolC is required for functioning of the Mar/AcrAB efflux pump of Escherichia coli. J Bacteriol 1996;178:5803–5805.

    PubMed  CAS  Google Scholar 

  15. Nishino K, Yamaguchi A. EvgA of the two-component signal transduction system modulates production of the yhiUV multidrug transporter in Escherichia coli. J Bacteriol 2002;184:2319–2323.

    Article  PubMed  CAS  Google Scholar 

  16. Paulsen IT, Sliwinski MK, Saier MH. Microbial genome analyses: global comparisons of transport capabilities based on phylogenies, bioenergetics and substrate specificities. J Mol Biol 1998;277:573–592.

    Article  PubMed  CAS  Google Scholar 

  17. Paulsen IT, Nguyen L, Sliwinski MK, Rabus R, Saier MH. Microbial genome analyses: comparative transport capabilities in 18 prokaryotes. J Mol Biol 2000;301:75–100.

    Article  PubMed  CAS  Google Scholar 

  18. Ahmed M, Borsch CM, Taylor SS, Vazquez-Laslop N, Neyfakh AA. A protein that activates expression of a multidrug efflux transporter upon binding the transporter substrates. J Biol Chem 1994;269:28 506–513.

    Google Scholar 

  19. Brooun A, Tomashek JJ, Lewis K. Purification and ligand binding of EmrR, a regulator of a multidrug transporter. J Bacteriol 1999;181:5131–5133.

    PubMed  CAS  Google Scholar 

  20. Lomovskaya O, Lewis K, Matin A. EmrR is a negative regulator of the Escherichia coli multidrug resistance pump EmrAB. J Bacteriol 1995;177:2328–2334.

    PubMed  CAS  Google Scholar 

  21. Grkovic S, Brown MH, Skurray RA. Regulation of bacterial drug export systems. Microbiol Mol Biol Rev 2002;66:671–701.

    Article  PubMed  CAS  Google Scholar 

  22. Ma D, Alberti M, Lynch C, Nikaido H, Hearst JE. The local repressor AcrR plays a modulating role in the regulation of acrAB genes of Escherichia coli by global stress signals. Mol Microbiol 1996;19:101–112.

    Article  PubMed  CAS  Google Scholar 

  23. Randall LP, Woodward MJ. The multiple antibiotic resistance (mar) locus and its significance. Res Vet Sci 2002;72:87–93.

    Article  PubMed  CAS  Google Scholar 

  24. Rosenberg EY, Bertenthal D, Nilles ML, Bertrand KP, Nikaido H. Bile salts and fatty acids induce the expression of Escherichia coli AcrAB multidrug efflux pump through their interaction with Rob regulatory protein. Mol Microbiol 2003;48:1609–1619.

    Article  PubMed  CAS  Google Scholar 

  25. Smith JL. The role of gastric acid in preventing foodborne disease and how bacteria overcome acid conditions. J Food Prot 2003;66:1292–1303.

    PubMed  Google Scholar 

  26. Gorden J, Small PL. Acid resistance in enteric bacteria. Infect Immun 1993;61:364–367.

    PubMed  CAS  Google Scholar 

  27. Lin J, Smith MP, Chapin KC, Baik HS, Bennett GN, Foster JW. Mechanisms of acid resistance in enterohemorrhagic Escherichia coli. Appl Environ Microbiol 1996;62:3094–3100.

    PubMed  CAS  Google Scholar 

  28. Giannella RA, Broitman SA, Zamcheck N. Influence of gastric acidity on bacterial and parasitic enteric infections. A perspective. Ann Intern Med 1973;78:271–276.

    PubMed  CAS  Google Scholar 

  29. Price SB, Wright JC, DeGraves FJ, Castanie-Cornet MP, Foster JW. Acid resistance systems required for survival of Escherichia coli O157:H7 in the bovine gastrointestinal tract and in apple cider are different. Appl Environ Microbiol 2004;70:4792–4799.

    Article  PubMed  CAS  Google Scholar 

  30. Castanie-Cornet MP, Penfound TA, Smith D, Elliott JF, Foster JW. Control of acid resistance in Escherichia coli. J Bacteriol 1999;181:3525–3535.

    PubMed  CAS  Google Scholar 

  31. De Biase D, Tramonti A, Bossa F, Visca P. The response to stationary-phase stress conditions in Escherichia coli: role and regulation of the glutamic acid decarboxylase system. Mol Microbiol 1999;32:1198–1211.

    Article  PubMed  Google Scholar 

  32. Giangrossi M, Zattoni S, Tramonti A, De Biase D, Falconi M. Antagonistic role of H-NS and GadX in the regulation of the glutamate decarboxylase-dependent acid resistance system in Escherichia coli. J Biol Chem 2005;280:21 498–505.

    Google Scholar 

  33. Blattner FR, Plunkett G, Bloch CA, Perna NT, Burland V, Riley M, et al. The complete genome sequence of Escherichia coli K-12. Science 1997;277:1453–1474.

    Article  PubMed  CAS  Google Scholar 

  34. Davis RW, Bolstein D, Roth JR. Advanced bacterial genetics. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory; 1980.

    Google Scholar 

  35. Sambrook J, Fritsch EF, Maniatis T. Molecular cloning: a laboratory manual, 2nd ed. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory; 1989.

    Google Scholar 

  36. Datsenko KA, Wanner BL. One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc Natl Acad Sci USA 2000;97:6640–6645.

    Article  PubMed  CAS  Google Scholar 

  37. Nishino K, Yamaguchi A. Role of histone-like protein H-NS in multidrug resistance of Escherichia coli. J Bacteriol 2004;186:1423–1429.

    Article  PubMed  CAS  Google Scholar 

  38. Nishino K, Honda T, Yamaguchi A. Genome-wide analyses of Escherichia coli gene expression responsive to the BaeSR two-component regulatory system. J Bacteriol 2005;187:1763–1772.

    Article  PubMed  CAS  Google Scholar 

  39. Nishino K, Yamaguchi A. Overexpression of the response regulator evgA of the two-component signal transduction system modulates multidrug resistance conferred by multidrug resistance transporters. J Bacteriol 2001;183:1455–1458.

    Article  PubMed  CAS  Google Scholar 

  40. Nishino K, Inazumi Y, Yamaguchi A. Global analysis of genes regulated by EvgA of the two-component regulatory system in Escherichia coli. J Bacteriol 2003;185:2667–2672.

    Article  PubMed  CAS  Google Scholar 

  41. Nishino K, Latifi T, Groisman EA. Virulence and drug resistance roles of multidrug efflux systems of Salmonella enterica serovar Typhimurium. Mol Microbiol 2006;59:126–141.

    Article  PubMed  CAS  Google Scholar 

  42. Hommais F, Krin E, Laurent-Winter C, Soutourina O, Malpertuy A, Le Caer JP, et al. Large-scale monitoring of pleiotropic regulation of gene expression by the prokaryotic nucleoid-associated protein, H-NS. Mol Microbiol 2001;40:20–36.

    Article  PubMed  CAS  Google Scholar 

  43. Gallegos MT, Schleif R, Bairoch A, Hofmann K, Ramos JL. Arac/XylS family of transcriptional regulators. Microbiol Mol Biol Rev 1997;61:393–410.

    PubMed  CAS  Google Scholar 

  44. Martin RG, Rosner JL. The AraC transcriptional activators. Curr Opin Microbiol 2001;4:132–137.

    Article  PubMed  CAS  Google Scholar 

  45. Tramonti A, Visca P, De Canio M, Falconi M, De Biase D. Functional characterization and regulation of gadX, a gene encoding an AraC/XylS-like transcriptional activator of the Escherichia coli glutamic acid decarboxylase system. J Bacteriol 2002;184:2603–2613.

    Article  PubMed  CAS  Google Scholar 

  46. Kobayashi A, Hirakawa H, Hirata T, Nishino K, Yamaguchi A. Growth phase-dependent expression of drug exporters in Escherichia coli and its contribution to drug tolerance. J Bacteriol 2006;188:5693–5703.

    Article  PubMed  CAS  Google Scholar 

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Correspondence to Kunihiko Nishino or Akihito Yamaguchi.

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Nishino, K., Senda, Y. & Yamaguchi, A. The AraC-family regulator GadX enhances multidrug resistance in Escherichia coli by activating expression of mdtEF multidrug efflux genes. J Infect Chemother 14, 23–29 (2008). https://doi.org/10.1007/s10156-007-0575-y

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  • DOI: https://doi.org/10.1007/s10156-007-0575-y

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