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Brychcy M, Nguyen B, Tierney GA, Casula P, Kokodynski A, Godoy VG. The metabolite vanillic acid regulates Acinetobacter baumannii surface attachment. Mol Microbiol 2024; 121:833-849. [PMID: 38308563 DOI: 10.1111/mmi.15234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 02/05/2024]
Abstract
The nosocomial bacterium Acinetobacter baumannii is protected from antibiotic treatment by acquiring antibiotic resistances and by forming biofilms. Cell attachment, one of the first steps in biofilm formation, is normally induced by environmental metabolites. We hypothesized that vanillic acid (VA), the oxidized form of vanillin and a widely available metabolite, may play a role in A. baumannii cell attachment. We first discovered that A. baumannii actively breaks down VA through the evolutionarily conserved vanABKP genes. These genes are under the control of the repressor VanR, which we show binds directly to VanR binding sites within the vanABKP genes bidirectional promoter. VA in turn counteracts VanR inhibition. We identified a VanR binding site and searched for it throughout the genome, especially in pili encoding promoter genes. We found a VanR binding site in the pilus encoding csu operon promoter and showed that VanR binds specifically to it. As expected, a strain lacking VanR overproduces Csu pili and makes robust biofilms. Our study uncovers the role that VA plays in facilitating the attachment of A. baumannii cells to surfaces, a crucial step in biofilm formation. These findings provide valuable insights into a previously obscure catabolic pathway with significant clinical implications.
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Affiliation(s)
- Merlin Brychcy
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Brian Nguyen
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | | | - Pranav Casula
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Alexis Kokodynski
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Veronica G Godoy
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
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Ching C, Brychcy M, Nguyen B, Muller P, Pearson AR, Downs M, Regan S, Isley B, Fowle W, Chai Y, Godoy VG. RecA levels modulate biofilm development in Acinetobacter baumannii. Mol Microbiol 2024; 121:196-212. [PMID: 37918886 DOI: 10.1111/mmi.15188] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 11/04/2023]
Abstract
Infections caused by Acinetobacter baumannii, a Gram-negative opportunistic pathogen, are difficult to eradicate due to the bacterium's propensity to quickly gain antibiotic resistances and form biofilms, a protective bacterial multicellular community. The A. baumannii DNA damage response (DDR) mediates the antibiotic resistance acquisition and regulates RecA in an atypical fashion; both RecALow and RecAHigh cell types are formed in response to DNA damage. The findings of this study demonstrate that the levels of RecA can influence formation and dispersal of biofilms. RecA loss results in surface attachment and prominent biofilms, while elevated RecA leads to diminished attachment and dispersal. These findings suggest that the challenge to treat A. baumannii infections may be explained by the induction of the DDR, common during infection, as well as the delicate balance between maintaining biofilms in low RecA cells and promoting mutagenesis and dispersal in high RecA cells. This study underscores the importance of understanding the fundamental biology of bacteria to develop more effective treatments for infections.
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Affiliation(s)
- Carly Ching
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Merlin Brychcy
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Brian Nguyen
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Paul Muller
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | | | - Margaret Downs
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Samuel Regan
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Breanna Isley
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - William Fowle
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Yunrong Chai
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
| | - Veronica G Godoy
- Department of Biology, Northeastern University, Boston, Massachusetts, USA
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