Skip to main content

AbaR is a LuxR type regulator essential for motility and the formation of biofilm and pellicle in Acinetobacter baumannii

Abstract

Background

Acinetobacter baumannii is a major opportunistic pathogen causing nosocomial infections. Acinetobacter baumannii possesses a quorum sensing system consisting of abaI, encoding an autoinducer synthase, and abaR, encoding a putative LuxR type regulator. AbaI is required for motility and biofilm formation in A. baumannii. However, the functions of AbaR on the expression of abaI, motility, and the formation of biofilm and pellicle have not yet been explored.

Objective

The aim of this study was to investigate the effects of abaR mutation on the expression of abaI, motility, and the formation of biofilm and pellicle.

Methods

Functions of AbaR were assessed by the construction of an isogenic mutant and by evaluating the effects of abaR mutation on the expression of abaI, motility, and the formation of biofilm and pellicle.

Results

The abaR mutant revealed a significant decrease in the expression of abaI. The disruption of abaR resulted in substantial defects in motility and the formation of biofilm and pellicle. Introduction of abaR in trans complemented the defects.

Conclusions

AbaR of A. baumannii is required for the expression of abaI and plays important roles in motility and the formation of biofilm and pellicle. AbaR may be considered to be a target of anti-biofilm agents.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

References

  1. Amin IM, Richmond GE, Sen P, Koh TH, Piddock LJ, Chua KL (2013) A method for generating marker-less gene deletions in multidrug-resistant Acinetobacter baumannii. BMC Microbiol 13:158

    Article  Google Scholar 

  2. Bhargava N, Sharma P, Capalash N (2010) Quorum sensing in acinetobacter: an emerging pathogen. Crit Rev Microbiol 36:349–360

    CAS  Article  Google Scholar 

  3. Clemmer KM, Bonomo RA, Rather PN (2011) Genetic analysis of surface motility in Acinetobacter baumannii. Microbiology 157:2534–2544

    CAS  Article  Google Scholar 

  4. Dijkshoorn L, Nemec A, Seifert H (2007) An increasing threat in hospitals: multidrug-resistant Acinetobacter baumannii. Nat Rev Microbiol 5:939–951

    CAS  Article  Google Scholar 

  5. Eijkelkamp BA, Stroeher UH, Hassan KA, Elbourne LD, Paulsen IT, Brown MH (2013) H-NS plays a role in expression of Acinetobacter baumannii virulence features. Infect Immun 81:2574–2583

    CAS  Article  Google Scholar 

  6. Gaddy JA, Tomaras AP, Actis LA (2009) The Acinetobacter baumannii 19606 OmpA protein plays a role in biofilm formation on abiotic surfaces and in the interaction of this pathogen with eukaryotic cells. Infect Immun 77:3150–3160

    CAS  Article  Google Scholar 

  7. Harding CM, Tracy EN, Carruthers MD, Rather PN, Actis LA, Munson RS Jr (2013) Acinetobacter baumannii strain M2 produces type IV Pili which play a role in natural transformation and twitching motility but not surface-associated motility. mBio 4:e00360–13

    Article  Google Scholar 

  8. Hunger M, Schmucker R, Kishan V, Hillen W (1990) Analysis and nucleotide sequence of an origin of DNA replication in Acinetobacter calcoaceticus and its use for Escherichia coli shuttle plasmids. Gene 87:45–51

    CAS  Article  Google Scholar 

  9. Marti S, Nait Chabane Y, Alexandre S, Coquet L, Vila J, Jouenne T, De E (2011) Growth of Acinetobacter baumannii in pellicle enhanced the expression of potential virulence factors. PLoS One 6:e26030

    CAS  Article  Google Scholar 

  10. Milton DL, O’Toole R, Horstedt P, Wolf-Watz H (1996) Flagellin A is essential for the virulence of Vibrio anguillarum. J Bacteriol 178:1310–1319

    CAS  Article  Google Scholar 

  11. Niu C, Clemmer KM, Bonomo RA, Rather PN (2008) Isolation and characterization of an autoinducer synthase from Acinetobacter baumannii. J Bacteriol 190:3386–3392

    CAS  Article  Google Scholar 

  12. Ottemann KM, Miller JF (1997) Roles for motility in bacterial–host interactions. Mol Microbiol 24:1109–1117

    CAS  Article  Google Scholar 

  13. Parsek MR, Greenberg EP (2000) Acyl-homoserine lactone quorum sensing in Gram-negative bacteria: a signaling mechanism involved in associations with higher organisms. Proc Natl Acad Sci USA 97:8789–8793

    CAS  Article  Google Scholar 

  14. Piechaud M, Second L (1951) Studies of 26 strains of Moraxella lwoffii. Ann Inst Pasteur (Paris) 80:97–99

    CAS  Google Scholar 

  15. Rutherford ST, Bassler BL (2012) Bacterial quorum sensing: its role in virulence and possibilities for its control. Cold Spring Harb Perspect Med 2:a012427

    Article  Google Scholar 

  16. Sakuragi Y, Kolter R (2007) Quorum-sensing regulation of the biofilm matrix genes (pel) of Pseudomonas aeruginosa. J Bacteriol 189:5383–5386

    CAS  Article  Google Scholar 

  17. Seifert H, Strate A, Pulverer G (1995) Nosocomial bacteremia due to Acinetobacter baumannii. Clinical features, epidemiology, and predictors of mortality. Medicine 74:340–349

    CAS  Article  Google Scholar 

  18. Simon R, Priefer U, Pühler A (1983) A broad host range mobilization system for in vivo genetic engineering: transposon mutagenesis in gram negative bacteria. Nat Biotechnol 1:784–791

    CAS  Article  Google Scholar 

  19. Stacy DM, Welsh MA, Rather PN, Blackwell HE (2012) Attenuation of quorum sensing in the pathogen Acinetobacter baumannii using non-native N-acyl homoserine lactones. ACS Chem Biol 7:1719–1728

    CAS  Article  Google Scholar 

  20. Tomaras AP, Dorsey CW, Edelmann RE, Actis LA (2003) Attachment to and biofilm formation on abiotic surfaces by Acinetobacter baumannii: involvement of a novel chaperone-usher pili assembly system. Microbiology 149:3473–3484

    CAS  Article  Google Scholar 

  21. Tucker AT, Nowicki EM, Boll JM, Knauf GA, Burdis NC, Trent MS, Davies BW (2014) Defining gene–phenotype relationships in Acinetobacter baumannii through one-step chromosomal gene inactivation. mBio 5:e01313–e01314

    CAS  Article  Google Scholar 

Download references

Acknowledgements

The authors gratefully acknowledge the Center for Bio-Medical Engineering Core Facility at Dankook University for providing critical reagents and equipment.

Funding

This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health and Welfare, Republic of Korea (Grant number HI17C1657).

Author information

Affiliations

Authors

Corresponding author

Correspondence to Kyudong Han.

Ethics declarations

Conflict of interest

The authors declare that there is no conflict of interest regarding the publication of this paper.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Oh, M.H., Han, K. AbaR is a LuxR type regulator essential for motility and the formation of biofilm and pellicle in Acinetobacter baumannii. Genes Genom 42, 1339–1346 (2020). https://doi.org/10.1007/s13258-020-01005-8

Download citation

Keywords

  • Acinetobacter baumannii
  • Pathogen
  • Quorum sensing
  • Motility
  • Biofilm