1
|
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.
Collapse
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
| |
Collapse
|
2
|
Han P, Lin W, Fan H, Tong Y. Characterization of phage evolution and phage resistance in drug-resistant Stenotrophomonas maltophilia. J Virol 2024; 98:e0124923. [PMID: 38189285 PMCID: PMC10878236 DOI: 10.1128/jvi.01249-23] [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: 10/23/2023] [Accepted: 12/04/2023] [Indexed: 01/09/2024] Open
Abstract
Phage therapy has become a viable antimicrobial treatment as an alternative to antibiotic treatment, with an increase in antibiotic resistance. Phage resistance is a major limitation in the therapeutic application of phages, and the lack of understanding of the dynamic changes between bacteria and phages constrains our response strategies to phage resistance. In this study, we investigated the changing trends of mutual resistance between Stenotrophomonas maltophilia (S. maltophilia) and its lytic phage, BUCT603. Our results revealed that S. maltophilia resisted phage infection through mutations in the cell membrane proteins, while the evolved phage re-infected the resistant strain primarily through mutations in structure-related proteins. Compared with the wild-type strain (SMA118), the evolved phage-resistant strain (R118-2) showed reduced virulence, weakened biofilm formation ability, and reduced resistance to aminoglycosides. In addition, the evolved phage BUCT603B1 in combination with kanamycin could inhibit the development of phage-resistant S. maltophilia in vitro and significantly improve the survival rate of S. maltophilia-infected mice. Altogether, these results suggest that in vitro characterization of bacteria-phage co-evolutionary relationships is a useful research tool to optimize phages for the treatment of drug-resistant bacterial infections.IMPORTANCEPhage therapy is a promising approach to treat infections caused by drug-resistant Stenotrophomonas maltophilia (S. maltophilia). However, the rapid development of phage resistance has hindered the therapeutic application of phages. In vitro evolutionary studies of bacteria-phage co-cultures can elucidate the mechanism of resistance development between phage and its host. In this study, we investigated the resistance trends between S. maltophilia and its phage and found that inhibition of phage adsorption is the primary strategy by which bacteria resist phage infection in vitro, while phages can re-infect bacterial cells by identifying other adsorption receptors. Although the final bacterial mutants were no longer infected by phages, they incurred a fitness cost that resulted in a significant reduction in virulence. In addition, the combination treatment with phage and aminoglycoside antibiotics could prevent the development of phage resistance in S. maltophilia in vitro. These findings contribute to increasing the understanding of the co-evolutionary relationships between phages and S. maltophilia.
Collapse
Affiliation(s)
- Pengjun Han
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Wei Lin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Huahao Fan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Yigang Tong
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
| |
Collapse
|
3
|
Zhang Y, Han Y, Huang Z, Huang Y, Kong J, Sun Y, Cao J, Zhou T. Restoring Colistin Sensitivity and Combating Biofilm Formation: Synergistic Effects of Colistin and Usnic Acid against Colistin-Resistant Enterobacteriaceae. ACS Infect Dis 2023; 9:2457-2470. [PMID: 37944020 DOI: 10.1021/acsinfecdis.3c00315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Colistin (COL), the last line of defense in clinical medicine, is an important therapeutic option against multidrug-resistant Gram-negative bacteria. In this context, the emergence of colistin-resistant (COL-R) bacteria mediated by broad-spectrum efflux pumps, mobile genetic elements, and biofilm formation poses a significant public health concern. In response to this challenge, a novel approach of combining COL with usnic acid (UA) has been proposed in this study. UA is a secondary metabolite derived from lichens and is well-known for its anti-inflammatory properties. This study aimed to investigate the synergistic effects of UA and COL against COL-R Enterobacteriaceae both in vitro and in vivo. The exceptional synergistic antibacterial activity exhibited by the combination of COL and UA was demonstrated by performing a comprehensive set of assays, including the checkerboard assay, time-dependent killing assay, and Live/Dead bacterial cell viability assay. Furthermore, crystal violet staining and scanning electron microscopy assays revealed the inhibitory effect of this combination on the biofilm formation. Mechanistically, the combination of UA and COL exacerbated cell membrane rupture, induced DNA damage, and generated a significant amount of reactive oxygen species, which ultimately resulted in bacterial cell death. In addition, erythrocyte hemolysis and cell viability tests confirmed the biocompatibility of the combination. The evaluation of the COL/UA combination in vivo using Galleria mellonella larvae and a mouse infection model showed a significant improvement in the survival rate of the infected larvae as well as a reduction in the bacterial load in the mouse thigh muscle. These findings, for the first time, provide strong evidence for the potential application of COL/UA as an effective alternative therapeutic option to combat infections caused by COL-R Enterobacteriaceae strains.
Collapse
Affiliation(s)
- Yi Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province 325000, China
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province 32500, China
| | - Yijia Han
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province 32500, China
| | - Zeyu Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province 325000, China
| | - Yali Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province 325000, China
| | - Jingchun Kong
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province 32500, China
| | - Yao Sun
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province 325000, China
| | - Jianming Cao
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province 32500, China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University; Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province 325000, China
| |
Collapse
|
4
|
Zhang Y, Han Y, Wang L, Kong J, Pan W, Zhang X, Chen L, Yao Z, Zhou T, Cao J. Flufenamic Acid, a Promising Agent for the Sensitization of Colistin-Resistant Gram-Negative Bacteria to Colistin. Microbiol Spectr 2023; 11:e0405222. [PMID: 36971552 PMCID: PMC10100705 DOI: 10.1128/spectrum.04052-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 03/06/2023] [Indexed: 03/29/2023] Open
Abstract
The continuous development of multidrug-resistant (MDR) Gram-negative bacteria poses a serious risk to public health on a worldwide scale. Colistin is used as the last-line antibiotic for the treatment of MDR pathogens, and colistin-resistant (COL-R) bacterial emergence thus has the potential to have a severe adverse impact on patient outcomes. In this study, synergistic activity was observed when colistin and flufenamic acid (FFA) were combined and used for the in vitro treatment of clinical COL-R Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii strains, as shown by checkerboard and time-kill assays. Crystal violet staining and scanning electron microscopy revealed the synergistic action of colistin-FFA against biofilms. When used to treat murine RAW264.7 macrophages, this combination did not induce any adverse toxicity. Strikingly, the survival rates of bacterially infected Galleria mellonella larvae were improved by such combination treatment, which was also sufficient to reduce the measured bacterial loads in a murine thigh infection model. Mechanistic propidium iodide (PI) staining analysis further demonstrated the ability of these agents to alter bacterial permeability in a manner that enhanced the efficacy of colistin treatment. Together, these data thus demonstrate that colistin and FFA can be synergistically combined to combat the spread of COL-R Gram-negative bacteria, providing a promising therapeutic tool with the potential to protect against COL-R bacterial infections and improve patient outcomes. IMPORTANCE Colistin is a last-line antibiotic used for the treatment of MDR Gram-negative bacterial infections. However, increasing resistance to it has been observed during clinical treatment. In this work, we assessed the efficacy of the combination of colistin and FFA for the treatment of COL-R bacterial isolates, demonstrating that the combined treatment has effective antibacterial and antibiofilm activities. Due to its low cytotoxicity and good therapeutic effects in vitro, the colistin-FFA combination may be a potential candidate for research into a resistance-modifying agent to combat infections caused by COL-R Gram-negative bacteria.
Collapse
Affiliation(s)
- Yi Zhang
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yijia Han
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Lingbo Wang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, China
| | - Jingchun Kong
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Wei Pan
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, China
| | - Xiaodong Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, China
| | - Lijiang Chen
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, China
| | - Zhuocheng Yao
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, China
| | - Jianming Cao
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| |
Collapse
|