1887

Abstract

Resistance to the polycationic antibiotic polymyxin B and expression of the outer-membrane protein OprH in the opportunistic pathogen both involve the PhoP-PhoQ two-component regulatory system. The genes for this system form an operon with , , that responds to Mg starvation and PhoP levels. In this study, the Mg-regulated promoter for this operon was mapped upstream of by primer-extension experiments. An ::-Gm mutant H855 was constructed and measurement of the catechol 2,3-dioxygenase activity expressed from this transcriptional fusion provided evidence for a second, weak promoter for . Wild-type PAO1 strain H103 was found to exhibit Mg-regulated resistance to the α-helical antimicrobial cationic peptide CP28 in addition to its previously characterized resistance to polymyxin B. Resistance to this peptide was unchanged in the OprH-null mutant H855 and a PhoP-null mutant H851. In contrast, PhoQ-null mutant H854 demonstrated constitutive CP28 resistance. Northern blot analysis revealed constitutive expression of in this strain, implicating PhoP-PhoQ in the resistance of to cationic peptides. Furthermore, all three null-mutant strains demonstrated increased resistance to the aminoglycoside antibiotics streptomycin, kanamycin and amikacin. Two additional mutant strains, H895 and H896, were constructed that carried unmarked deletions in and were found to exhibit aminoglycoside susceptibility equivalent to that of the wild-type. This result provided definitive evidence that OprH is not involved in aminoglycoside resistance and that the changes in resistance in strain H855 and a previously reported mutant were due to polar effects on rather than loss of OprH expression. A role for PhoP-PhoQ in resistance to aminoglycosides is envisaged that is distinct from that in resistance to cationic peptides and polymyxin B.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-146-10-2543
2000-10-01
2024-04-23
Loading full text...

Full text loading...

/deliver/fulltext/micro/146/10/1462543a.html?itemId=/content/journal/micro/10.1099/00221287-146-10-2543&mimeType=html&fmt=ahah

References

  1. Amsterdam D. 1991 Antibiotics in Laboratory Medicine Baltimore, MD: Williams & Wilkins;
    [Google Scholar]
  2. Ausubel F. M., Brent R., Kingston R. E., Moore D. D., Seidman J. G., Smith J. A., Struhl K.editors 1987 Current Protocols in Molecular Biology New York: Greene Publishing and Wiley Interscience;
    [Google Scholar]
  3. Bajaj V., Lucas R. L., Hwang C., Lee C. A. 1996; Co-ordinate regulation of Salmonella typhimurium invasion genes by environmental and regulatory factors is mediated by control of hilA expression. Mol Microbiol 22:703–714 [CrossRef]
    [Google Scholar]
  4. Bell A., Bains M., Hancock R. E. 1991; Pseudomonas aeruginosa outer membrane protein OprH: expression from the cloned gene and function in EDTA and gentamicin resistance. J Bacteriol 173:6657–6664
    [Google Scholar]
  5. Brown M. R., Melling J. 1969; Role of divalent cations in the action of polymyxin B and EDTA on Pseudomonas aeruginosa. J Gen Microbiol 59:263–274 [CrossRef]
    [Google Scholar]
  6. Dennis J. J., Sokol P. A. 1995; Electrotransformation of Pseudomonas. Methods Mol Biol 47:125–133
    [Google Scholar]
  7. Ernst R. K., Yi E. C., Guo L., Lim K. B., Burns J. L., Hackett M., Miller S. I. 1999; Specific lipopolysaccharide found in cystic fibrosis airway Pseudomonas aeruginosa. Science 286:1561–1565 [CrossRef]
    [Google Scholar]
  8. Falla T. J., Hancock R. E. 1997; Improved activity of a synthetic indolicidin analog. Antimicrob Agents Chemother 41:771–775
    [Google Scholar]
  9. Fields P. I., Groisman E. A., Heffron F. 1989; A Salmonella locus that controls resistance to microbicidal proteins from phagocytic cells. Science 243:1059–1062 [CrossRef]
    [Google Scholar]
  10. Friedrich C., Scott M. G., Karunaratne N., Yan H., Hancock R. E. 1999; Salt-resistant alpha-helical cationic antimicrobial peptides. Antimicrob Agents Chemother 43:1542–1548
    [Google Scholar]
  11. Garcia Vescovi E., Soncini F. C., Groisman E. A. 1996; Mg2+ as an extracellular signal: environmental regulation of Salmonella virulence. Cell 84:165–174 [CrossRef]
    [Google Scholar]
  12. Gilleland H. E. Jr, Stinnett J. D., Eagon R. G. 1974; Ultrastructural and chemical alteration of the cell envelope of Pseudomonas aeruginosa, associated with resistance to ethylenediaminetetraacetate resulting from growth in a Mg2+-deficient medium. J Bacteriol 117:302–311
    [Google Scholar]
  13. Gunn J. S., Miller S. I. 1996; PhoP-PhoQ activates transcription of pmrAB, encoding a two-component regulatory system involved in Salmonella typhimurium antimicrobial peptide resistance. J Bacteriol 178:6857–6864
    [Google Scholar]
  14. Gunn J. S., Lim K. B., Krueger J., Kim K., Guo L., Hackett M., Miller S. I. 1998; PmrA-PmrB-regulated genes necessary for 4-aminoarabinose lipid A modification and polymyxin resistance. Mol Microbiol 27:1171–1182 [CrossRef]
    [Google Scholar]
  15. Guo L., Lim K. B., Poduje C. M., Daniel M., Gunn J. S., Hackett M., Miller S. I. 1998; Lipid A acylation and bacterial resistance against vertebrate antimicrobial peptides. Cell 95:189–198 [CrossRef]
    [Google Scholar]
  16. Hancock R. E., Chapple D. S. 1999; Peptide antibiotics. Antimicrob Agents Chemother 43:1317–1323
    [Google Scholar]
  17. Hancock R. E., Raffle V. J., Nicas T. I. 1981; Involvement of the outer membrane in gentamicin and streptomycin uptake and killing in Pseudomonas aeruginosa. Antimicrob Agents Chemother 19:777–785 [CrossRef]
    [Google Scholar]
  18. Helander I. M., Kilpelainen I., Vaara M. 1994; Increased substitution of phosphate groups in lipopolysaccharides and lipid A of the polymyxin-resistant pmrA mutants of Salmonella typhimurium: a 31P-NMR study. Mol Microbiol 11:481–487 [CrossRef]
    [Google Scholar]
  19. Iwanaga S., Muta T., Shigenaga T., Seki N., Kawano K., Katsu T., Kawabata S. 1994; Structure-function relationships of tachyplesins and their analogues. Ciba Found Symp 186:160–174
    [Google Scholar]
  20. Kato A., Tanabe H., Utsumi R. 1999; Molecular characterization of the PhoP-PhoQ two-component system in Escherichia coli K-12: identification of extracellular Mg2+-responsive promoters. J Bacteriol 181:5516–5520
    [Google Scholar]
  21. Macfarlane E. L., Kwasnicka A., Ochs M. M., Hancock R. E. 1999; PhoP-PhoQ homologues in Pseudomonas aeruginosa regulate expression of the outer-membrane protein OprH and polymyxin B resistance. Mol Microbiol 34:305–316 [CrossRef]
    [Google Scholar]
  22. Miller S. I., Kukral A. M., Mekalanos J. J. 1989; A two-component regulatory system (PhoP PhoQ) controls Salmonella typhimurium virulence. Proc Natl Acad Sci U S A 86:5054–5058 [CrossRef]
    [Google Scholar]
  23. Miller S. I., Pulkkinen W. S., Selsted M. E., Mekalanos J. J. 1990; Characterization of defensin resistance phenotypes associated with mutations in the phoP virulence regulon of Salmonella typhimurium. Infect Immun 58:3706–3710
    [Google Scholar]
  24. Nicas T. I., Hancock R. E. 1980; Outer membrane protein H1 of Pseudomonas aeruginosa: involvement in adaptive and mutational resistance to ethylenediaminetetraacetate, polymyxin B, and gentamicin. J Bacteriol 143:872–878
    [Google Scholar]
  25. Phillips I., Shannon K. 1984; Aminoglycoside resistance. Br Med Bull 40:28–35
    [Google Scholar]
  26. Piers K. L., Brown M. H., Hancock R. E. 1994; Improvement of outer membrane-permeabilizing and lipopolysaccharide-binding activities of an antimicrobial cationic peptide by C-terminal modification. Antimicrob Agents Chemother 38:2311–2316 [CrossRef]
    [Google Scholar]
  27. Rehm B. H., Hancock R. E. 1996; Membrane topology of the outer membrane protein OprH from Pseudomonas aeruginosa: PCR-mediated site-directed insertion and deletion mutagenesis. J Bacteriol 178:3346–3349
    [Google Scholar]
  28. Rothmel R. K., Chakrabarty A. M., Berry A., Darzins A. 1991; Genetic systems in Pseudomonas. Methods Enzymol 204:485–514
    [Google Scholar]
  29. Sambrook J., Fritsch E. F., Maniatis T. 1989 Molecular Cloning: a Laboratory Manual, 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
    [Google Scholar]
  30. Schweizer H. P. 1991; Escherichia-Pseudomonas shuttle vectors derived from pUC18/19. Gene 97:109–121 [CrossRef]
    [Google Scholar]
  31. Schweizer H. P., Hoang T. T. 1995; An improved system for gene replacement and xylE fusion analysis in Pseudomonas aeruginosa. Gene 158:15–22 [CrossRef]
    [Google Scholar]
  32. Simon R., Preifer V., Puhler A. 1983; A broad host range mobilization system for in vivo genetic engineering: transposon mutagenesis in Gram negative bacteria. Bio/Technology 1:784–790 [CrossRef]
    [Google Scholar]
  33. Soncini F. C., Groisman E. A. 1996; Two-component regulatory systems can interact to process multiple environmental signals. J Bacteriol 178:6796–6801
    [Google Scholar]
  34. Soncini F. C., Garcia Vescovi E., Groisman E. A. 1995; Transcriptional autoregulation of the Salmonella typhimurium phoPQ operon. J Bacteriol 177:4364–4371
    [Google Scholar]
  35. West S. E., Schweizer H. P., Dall C., Sample A. K., Runyen-Janecky L. J. 1994; Construction of improved Escherichia-Pseudomonas shuttle vectors derived from pUC18/19 and sequence of the region required for their replication in Pseudomonas aeruginosa. Gene 148:81–86 [CrossRef]
    [Google Scholar]
  36. Wu M., Hancock R. E. 1999; Interaction of the cyclic antimicrobial cationic peptide bactenecin with the outer and cytoplasmic membrane. J Biol Chem 274:29–35 [CrossRef]
    [Google Scholar]
  37. Young M. L., Bains M., Bell A., Hancock R. E. 1992; Role of Pseudomonas aeruginosa outer membrane protein OprH in polymyxin and gentamicin resistance: isolation of an OprH-deficient mutant by gene replacement techniques. Antimicrob Agents Chemother 36:2566–2568 [CrossRef]
    [Google Scholar]
  38. Zimelis V. M., Jackson G. G. 1973; Activity of aminoglycoside antibiotics against Pseudomonas aeruginosa: specificity and site of calcium and magnesium antagonism. J Infect Dis 127:663–669 [CrossRef]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-146-10-2543
Loading
/content/journal/micro/10.1099/00221287-146-10-2543
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error