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Ghosh S, Orman MA. Exploring the links between SOS response, mutagenesis, and resistance during the recovery period. Antimicrob Agents Chemother 2024; 68:e0146223. [PMID: 38534113 PMCID: PMC11064565 DOI: 10.1128/aac.01462-23] [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: 11/07/2023] [Accepted: 03/05/2024] [Indexed: 03/28/2024] Open
Abstract
Although the mechanistic connections between SOS-induced mutagenesis and antibiotic resistance are well established, our current understanding of the impact of SOS response levels, recovery durations, and transcription/translation activities on mutagenesis remains relatively limited. In this study, when bacterial cells were exposed to mutagens like ultraviolet light for defined time intervals, a compelling connection between the rate of mutagenesis and the RecA-mediated SOS response levels became evident. Our observations also indicate that mutagenesis primarily occurs during the subsequent recovery phase following the removal of the mutagenic agent. When transcription/translation was inhibited or energy molecules were depleted at the onset of treatment or during the early recovery phase, there was a noticeable decrease in SOS response activation and mutagenesis. However, targeting these processes later in the recovery phase does not have the same effect in reducing mutagenesis, suggesting that the timing of inhibiting transcription/translation or depleting energy molecules is crucial for their efficacy in reducing mutagenesis. Active transcription, translation, and energy availability within the framework of SOS response and DNA repair mechanisms appear to be conserved attributes, supported by their consistent manifestation across diverse conditions, including the use of distinct mutagens such as fluoroquinolones and various bacterial strains.
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Affiliation(s)
- Sreyashi Ghosh
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, USA
| | - Mehmet A. Orman
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, USA
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2
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Zoheir AE, Sobol MS, Meisch L, Ordoñez-Rueda D, Kaster AK, Niemeyer CM, Rabe KS. A three-colour stress biosensor reveals multimodal response in single cells and spatiotemporal dynamics of biofilms. NPJ Biofilms Microbiomes 2023; 9:57. [PMID: 37604827 PMCID: PMC10442448 DOI: 10.1038/s41522-023-00424-1] [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: 01/14/2023] [Accepted: 07/31/2023] [Indexed: 08/23/2023] Open
Abstract
The plethora of stress factors that can damage microbial cells has evolved sophisticated stress response mechanisms. While existing bioreporters can monitor individual responses, sensors for detecting multimodal stress responses in living microorganisms are still lacking. Orthogonally detectable red, green, and blue fluorescent proteins combined in a single plasmid, dubbed RGB-S reporter, enable simultaneous, independent, and real-time analysis of the transcriptional response of Escherichia coli using three promoters which report physiological stress (PosmY for RpoS), genotoxicity (PsulA for SOS), and cytotoxicity (PgrpE for RpoH). The bioreporter is compatible with standard analysis and Fluorescent Activated Cell Sorting (FACS) combined with subsequent transcriptome analysis. Various stressors, including the biotechnologically relevant 2-propanol, activate one, two, or all three stress responses, which can significantly impact non-stress-related metabolic pathways. Implemented in microfluidic cultivation with confocal fluorescence microscopy imaging, the RGB-S reporter enabled spatiotemporal analysis of live biofilms revealing stratified subpopulations of bacteria with heterogeneous stress responses.
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Affiliation(s)
- Ahmed E Zoheir
- Institute for Biological Interfaces 1 (IBG-1), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
- Department of Genetics and Cytology, National Research Centre (NRC), Cairo, Egypt
| | - Morgan S Sobol
- Institute for Biological Interfaces 5 (IBG-5), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Laura Meisch
- Institute for Biological Interfaces 1 (IBG-1), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Diana Ordoñez-Rueda
- European Molecular Biology Laboratory (EMBL), Flow Cytometry Core Facility, Heidelberg, Germany
| | - Anne-Kristin Kaster
- Institute for Biological Interfaces 5 (IBG-5), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Christof M Niemeyer
- Institute for Biological Interfaces 1 (IBG-1), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
| | - Kersten S Rabe
- Institute for Biological Interfaces 1 (IBG-1), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany.
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3
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Yahya AH, Harston SR, Colton WL, Cabeen MT. Distinct Screening Approaches Uncover PA14_36820 and RecA as Negative Regulators of Biofilm Phenotypes in Pseudomonas aeruginosa PA14. Microbiol Spectr 2023; 11:e0377422. [PMID: 36971546 PMCID: PMC10100956 DOI: 10.1128/spectrum.03774-22] [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: 12/21/2022] [Accepted: 02/28/2023] [Indexed: 03/29/2023] Open
Abstract
Pseudomonas aeruginosa commonly infects hospitalized patients and the lungs of individuals with cystic fibrosis. This species is known for forming biofilms, which are communities of bacterial cells held together and encapsulated by a self-produced extracellular matrix. The matrix provides extra protection to the constituent cells, making P. aeruginosa infections challenging to treat. We previously identified a gene, PA14_16550, which encodes a DNA-binding TetR-type repressor and whose deletion reduced biofilm formation. Here, we assessed the transcriptional impact of the 16550 deletion and found six differentially regulated genes. Among them, our results implicated PA14_36820 as a negative regulator of biofilm matrix production, while the remaining 5 had modest effects on swarming motility. We also screened a transposon library in a biofilm-impaired ΔamrZ Δ16550 strain for restoration of matrix production. Surprisingly, we found that disruption or deletion of recA increased biofilm matrix production, both in biofilm-impaired and wild-type strains. Because RecA functions both in recombination and in the DNA damage response, we asked which function of RecA is important with respect to biofilm formation by using point mutations in recA and lexA to specifically disable each function. Our results implied that loss of either function of RecA impacts biofilm formation, suggesting that enhanced biofilm formation may be one physiological response of P. aeruginosa cells to loss of either RecA function. IMPORTANCE Pseudomonas aeruginosa is a notorious human pathogen well known for forming biofilms, communities of bacteria that protect themselves within a self-secreted matrix. Here, we sought to find genetic determinants that impacted biofilm matrix production in P. aeruginosa strains. We identified a largely uncharacterized protein (PA14_36820) and, surprisingly, RecA, a widely conserved bacterial DNA recombination and repair protein, as negatively regulating biofilm matrix production. Because RecA has two main functions, we used specific mutations to isolate each function and found that both functions influenced matrix production. Identifying negative regulators of biofilm production may suggest future strategies to reduce the formation of treatment-resistant biofilms.
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Affiliation(s)
- Amal H. Yahya
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Sophie R. Harston
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - William L. Colton
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Matthew T. Cabeen
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
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4
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Crane JK, Catanzaro MN. Role of Extracellular DNA in Bacterial Response to SOS-Inducing Drugs. Antibiotics (Basel) 2023; 12:antibiotics12040649. [PMID: 37107011 PMCID: PMC10135224 DOI: 10.3390/antibiotics12040649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/16/2023] [Accepted: 03/21/2023] [Indexed: 04/29/2023] Open
Abstract
The SOS response is a conserved stress response pathway that is triggered by DNA damage in the bacterial cell. Activation of this pathway can, in turn, cause the rapid appearance of new mutations, sometimes called hypermutation. We compared the ability of various SOS-inducing drugs to trigger the expression of RecA, cause hypermutation, and produce elongation of bacteria. During this study, we discovered that these SOS phenotypes were accompanied by the release of large amounts of DNA into the extracellular medium. The release of DNA was accompanied by a form of bacterial aggregation in which the bacteria became tightly enmeshed in DNA. We hypothesize that DNA release triggered by SOS-inducing drugs could promote the horizontal transfer of antibiotic resistance genes by transformation or by conjugation.
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Affiliation(s)
- John K Crane
- Division of Infectious Diseases, Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - Marissa N Catanzaro
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA
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5
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Sazykin IS, Sazykina MA. The role of oxidative stress in genome destabilization and adaptive evolution of bacteria. Gene X 2023; 857:147170. [PMID: 36623672 DOI: 10.1016/j.gene.2023.147170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 12/14/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
The review is devoted to bacterial genome destabilization by oxidative stress. The article discusses the main groups of substances causing such stress. Stress regulons involved in destabilization of genetic material and mechanisms enhancing mutagenesis, bacterial genome rearrangements, and horizontal gene transfer, induced by oxidative damage to cell components are also considered. Based on the analysis of publications, it can be claimed that rapid development of new food substrates and ecological niches by microorganisms occurs due to acceleration of genetic changes induced by oxidative stress, mediated by several stress regulons (SOS, RpoS and RpoE) and under selective pressure. The authors conclude that non-lethal oxidative stress is probably-one of the fundamental processes that guide evolution of prokaryotes and a powerful universal trigger for adaptive destabilization of bacterial genome under changing environmental conditions.
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Affiliation(s)
- I S Sazykin
- Southern Federal University, 194/2 Stachki Avenue, Rostov-on-Don 344090, Russian Federation
| | - M A Sazykina
- Southern Federal University, 194/2 Stachki Avenue, Rostov-on-Don 344090, Russian Federation.
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6
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Radwan EK, Rashdan HRM, Hemdan BA, Koryam AA, El-Naggar ME. A dual-functional sulfone biscompound containing 1,2,3-triazole moiety for decolorization and disinfection of contaminated water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:77238-77252. [PMID: 35676578 PMCID: PMC9581830 DOI: 10.1007/s11356-022-20932-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/13/2022] [Indexed: 05/28/2023]
Abstract
Water decontamination from toxic dyes and pathogenic microorganisms is critical for life on Earth. Herein, we report the synthesis of sulfone biscompound containing 1,2,3-triazole moiety and evaluation of its dye decolorization and biocidal and disinfection efficiencies. The decolorization efficiency was tested under different experimental conditions, while the biocidal action was examined against various types of waterborne pathogens, and the disinfection of some pathogenic microbes was executed in artificially contaminated water. The findindgs illustrated that the solution initial pH (pHi) affected the decolorization efficiency significantly. About complete removal of 10 mg/L malachite green (MG) dye was achieved after 10 min using 3 g/L of the sulfone biscompound at pHi 6. The pseudo-second-order equation suited the adsorption kinetics accurately, while the equilibrium data was suited by Langmuir isotherm model. Electrostatic, n-π, and π-π interactions brought about the adsorption of MG onto the sulfone biscompound. The biocidal results indicated that the sulfone biscompound had a powerful antibacterial potential against the tested bacterial species. Likewise, the distinction trail revealed that after 70-90 min of direct contact with an effective dose, the tested pathogens could be completely eliminated (6-log reduction). Overall, the newly synthesized sulfone biscompound can efficiently remove cationic dyes and disinfect contaminated water.
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Affiliation(s)
- Emad K Radwan
- Water Pollution Research Department, National Research Centre, 33 El Buhouth St, Dokki, Giza, 12622, Egypt.
| | - Huda R M Rashdan
- Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre, 33 El Buhouth St, Dokki, Giza, 12622, Egypt
| | - Bahaa A Hemdan
- Water Pollution Research Department, National Research Centre, 33 El Buhouth St, Dokki, Giza, 12622, Egypt
| | - Asmaa A Koryam
- Water Pollution Research Department, National Research Centre, 33 El Buhouth St, Dokki, Giza, 12622, Egypt
| | - Mehrez E El-Naggar
- Institute of Textile Research and Technology, National Research Centre, 33 El Bohouth St, Dokki, Giza, 12622, Egypt.
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7
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Lima-Noronha MA, Fonseca DLH, Oliveira RS, Freitas RR, Park JH, Galhardo RS. Sending out an SOS - the bacterial DNA damage response. Genet Mol Biol 2022; 45:e20220107. [PMID: 36288458 PMCID: PMC9578287 DOI: 10.1590/1678-4685-gmb-2022-0107] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/15/2022] [Indexed: 11/04/2022] Open
Abstract
The term “SOS response” was first coined by Radman in 1974, in an intellectual effort to put together the data suggestive of a concerted gene expression program in cells undergoing DNA damage. A large amount of information about this cellular response has been collected over the following decades. In this review, we will focus on a few of the relevant aspects about the SOS response: its mechanism of control and the stressors which activate it, the diversity of regulated genes in different species, its role in mutagenesis and evolution including the development of antimicrobial resistance, and its relationship with mobile genetic elements.
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Affiliation(s)
- Marco A. Lima-Noronha
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
| | - Douglas L. H. Fonseca
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
| | - Renatta S. Oliveira
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
| | - Rúbia R. Freitas
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
| | - Jung H. Park
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
| | - Rodrigo S. Galhardo
- Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil
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8
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Kaushik V, Tiwari M, Tiwari V. Interaction of RecA mediated SOS response with bacterial persistence, biofilm formation, and host response. Int J Biol Macromol 2022; 217:931-943. [PMID: 35905765 DOI: 10.1016/j.ijbiomac.2022.07.176] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/20/2022] [Accepted: 07/22/2022] [Indexed: 11/28/2022]
Abstract
Antibiotics have a primary mode of actions, and most of them have a common secondary mode of action via reactive species (ROS and RNS) mediated DNA damage. Bacteria have been able to tolerate this DNA damage by SOS (Save-Our-Soul) response. RecA is the universal essential key protein of the DNA damage mediated SOS repair in various bacteria including ESKAPE pathogens. In addition, antibiotics also triggers activation of various other bacterial mechanisms such as biofilm formation, host dependent responses, persister subpopulation formation. These supporting the survival of bacteria in unfriendly natural conditions i.e. antibiotic presence. This review highlights the detailed mechanism of RecA mediated SOS response as well as role of RecA-LexA interaction in SOS response. The review also focuses on inter-connection between DNA damage repair pathway (like SOS response) with other survival mechanisms of bacteria such as host mediated RecA induction, persister-SOS interplay, and biofilm-SOS interplay. This understanding of inter-connection of SOS response with different other survival mechanisms will prove beneficial in targeting the SOS response for prevention and development of therapeutics against recalcitrant bacterial infections. The review also covers the significance of RecA as a promising potent therapeutic target for hindering bacterial SOS response in prevailing successful treatments of bacterial infections and enhancing the conventional antibiotic efficiency.
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Affiliation(s)
- Vaishali Kaushik
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India.
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9
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Jaramillo AVC, Cory MB, Li A, Kohli RM, Wuest WM. Exploration of inhibitors of the bacterial LexA repressor-protease. Bioorg Med Chem Lett 2022; 65:128702. [PMID: 35351585 DOI: 10.1016/j.bmcl.2022.128702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/17/2022] [Accepted: 03/24/2022] [Indexed: 11/25/2022]
Abstract
Resistant and tolerant bacterial infections lead to billions in healthcare costs and cause hundreds of thousands of deaths each year. The bulk of current antibiotic research efforts focus on molecules which, although novel, are not immune from acquired resistance and seldomly affect tolerant populations. The bacterial SOS response has been implicated in several resistance and tolerance mechanisms, making it an attractive antibiotic target. Using small molecule inhibitors targeting a key step in the deployment of the SOS response, our approach focused on preventing the deployment of mechanisms such as biofilm formation, horizontal gene transfer, and error-prone DNA repair. Herein we report the synthesis and testing of analogs of a triazole-containing tricyclic inhibitor of LexA proteolysis, the key event in the SOS response. Our results hint that our inhibitor's may function by adopting a β-hairpin conformation, reminiscent of the native cleavage loop of LexA.
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Affiliation(s)
| | - Michael B Cory
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Allen Li
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahul M Kohli
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - William M Wuest
- Department of Chemistry, Emory University, Atlanta, GA, USA.
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10
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Joshi S, Ghosh P, Barage S, Basu B, Deobagkar DD. Genome-wide lone strand adenine methylation in Deinococcus radiodurans R1: Regulation of gene expression through DR0643-dependent adenine methylation. Microbiol Res 2022; 257:126964. [PMID: 35042054 DOI: 10.1016/j.micres.2022.126964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/19/2021] [Accepted: 01/11/2022] [Indexed: 10/19/2022]
Abstract
DNA methylation is a covalent modification of adenine or cytosine in the genome of an organism and is found in diverse microbes including the radiation resistant bacterium Deinococcus radiodurans R1. Although earlier findings have confirmed repression or de-repression of certain genes in adenine methyltransferase (DR_0643/Dam1DR) deficient D. radiodurans mutant however, the overall regulatory aspects of Dam1DR-mediated adenine methylation remain mostly unexplored. In the present study, we compared the genome-wide methylome and the corresponding transcriptome of D. radiodurans WT and Δdam1 mutant to explore the correlation between methylation and gene expression. In D. radiodurans, deletion of DR_0643 ORF (Δdam1) led to hypomethylation of 512 genes resulting in differential expression of 168 genes (99 genes are upregulated and 69 genes are downregulated). The modification patterns deduced for Dam1DR (DR_0643) and Dam2DR (DR_2267) were non-palindromic and atypical. Moreover, we observed methylation at opportunistic sites that show adenine methylation only in D. radiodurans Δdam1 and not in D. radiodurans WT. Correlation between the methylome and transcriptome suggests that hypomethylation at Dam1DR specific sites had both negative as well as a positive effects on gene expression. Pathways such as amino acid metabolism, transport, oxidative phosphorylation, quorum sensing, signal transduction, two-component system, glycolysis/gluconeogenesis, TCA cycle, glyoxylate and dicarboxylate metabolism were modulated by Dam1DR-mediated adenine methylation in D. radiodurans. Processes such as DNA repair, recombination, ATPase and transmembrane transporter activity were enriched when Dam1DR mutant was subjected to radiation stress. We further evaluated the molecular interactions and mode of binding between Dam1DR protein and S-adenosyl methionine using molecular docking followed by MD simulation. To get a better insight into the methylation mechanism, the Dam1DR-SAM complex was also docked with a DNA molecule to elucidate DNA-Dam1DR structural interaction during methyl-group transfer reaction. In summary, our work presents comprehensive and integrative approaches to investigate both functional and structural aspects of DNA adenine methyltransferase (Dam1DR) in D. radiodurans biology.
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Affiliation(s)
- Suraj Joshi
- Molecular Biology Research Laboratory, Department of Zoology, Savitribai Phule Pune University, Pune, India; Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India; Bioinformatics Centre, Savitribai Phule Pune University, Pune, India
| | - Payel Ghosh
- Bioinformatics Centre, Savitribai Phule Pune University, Pune, India.
| | - Sagar Barage
- Amity Institute of Biotechnology, Amity University, Mumbai - Pune Expressway, Bhatan, Post-Somathne, Panvel, Maharashtra, 410206, India
| | - Bhakti Basu
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
| | - Deepti D Deobagkar
- Molecular Biology Research Laboratory, Department of Zoology, Savitribai Phule Pune University, Pune, India.
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Shimamura Y, Yui T, Horiike H, Masuda S. Toxicity of combined exposure to acrylamide and Staphylococcus aureus. Toxicol Rep 2022; 9:876-882. [DOI: 10.1016/j.toxrep.2022.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 04/17/2022] [Accepted: 04/18/2022] [Indexed: 11/26/2022] Open
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Gajdács M, Kárpáti K, Nagy ÁL, Gugolya M, Stájer A, Burián K. Association between biofilm-production and antibiotic resistance in Escherichia coli isolates: A laboratory-based case study and a literature review. Acta Microbiol Immunol Hung 2021. [PMID: 34524972 DOI: 10.1556/030.2021.01487] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/30/2021] [Indexed: 12/20/2022]
Abstract
Bacteria can enhance their survival by attaching to inanimate surfaces or tissues, and presenting as multicellular communities encased in a protective extracellular matrix called biofilm. There has been pronounced interest in assessing the relationship between the antibiotic resistant phenotype and biofilm-production in clinically-relevant pathogens. The aim of the present paper was to provide additional experimental results on the topic, testing the biofilm-forming capacity of Escherichia coli isolates using in vitro methods in the context of their antibiotic resistance in the form of a laboratory case study, in addition to provide a comprehensive review of the subject. In our case study, a total of two hundred and fifty (n = 250) E. coli isolates, originating from either clean-catch urine samples (n = 125) or invasive samples (n = 125) were included. The colony morphology of isolates were recorded after 24h, while antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Biofilm-formation of the isolates was assessed with the crystal violet tube-adherence method. Altogether 57 isolates (22.8%) isolates were multidrug resistant (MDR), 89 isolates (35.6%) produced large colonies (>3 mm), mucoid variant colonies were produced in 131 cases (52.4%), and 108 (43.2%) were positive for biofilm formation. Biofilm-producers were less common among isolates resistant to third-generation cephalosporins and trimethoprim-sulfamethoxazole (P = 0.043 and P = 0.023, respectively). Biofilms facilitate a protective growth strategy in bacteria, ensuring safety against environmental stressors, components of the immune system and noxious chemical agents. Being an integral part of bacterial physiology, biofilm-formation is interdependent with the expression of other virulence factors (especially adhesins) and quorum sensing signal molecules. More research is required to allow for the full understanding of the interplay between the MDR phenotype and biofilm-production, which will facilitate the development of novel therapeutic strategies.
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Affiliation(s)
- Márió Gajdács
- 1Department of Oral Biology and Experimental Dental Research, Faculty of Dentistry, University of Szeged, Tisza Lajos krt 63., 6720 Szeged, Hungary
- 2Institute of Medical Microbiology, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., 1089 Budapest, Hungary
| | - Krisztina Kárpáti
- 3Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, University of Szeged, Tisza Lajos körút 64-66., 6720 Szeged, Hungary
| | - Ádám László Nagy
- 4Department of Prosthodontics, Faculty of Dentistry, University of Szeged, Tisza Lajos körút 62-64., 6720 Szeged, Hungary
| | - Máté Gugolya
- 2Institute of Medical Microbiology, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., 1089 Budapest, Hungary
| | - Anette Stájer
- 5Department of Periodontology, Faculty of Dentistry, University of Szeged, Tisza Lajos körút 62-64., 6720 Szeged, Hungary
| | - Katalin Burián
- 6Department of Medical Microbiology, Albert Szent-Györgyi Health Center and Faculty of Medicine, University of Szeged, Semmelweis utca 6., 6725 Szeged, Hungary
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13
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Cai YM, Zhang YD, Yang L. NO donors and NO delivery methods for controlling biofilms in chronic lung infections. Appl Microbiol Biotechnol 2021; 105:3931-3954. [PMID: 33937932 PMCID: PMC8140970 DOI: 10.1007/s00253-021-11274-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/23/2021] [Accepted: 04/05/2021] [Indexed: 12/18/2022]
Abstract
Nitric oxide (NO), the highly reactive radical gas, provides an attractive strategy in the control of microbial infections. NO not only exhibits bactericidal effect at high concentrations but also prevents bacterial attachment and disperses biofilms at low, nontoxic concentrations, rendering bacteria less tolerant to antibiotic treatment. The endogenously generated NO by airway epithelium in healthy populations significantly contributes to the eradication of invading pathogens. However, this pathway is often compromised in patients suffering from chronic lung infections where biofilms dominate. Thus, exogenous supplementation of NO is suggested to improve the therapeutic outcomes of these infectious diseases. Compared to previous reviews focusing on the mechanism of NO-mediated biofilm inhibition, this review explores the applications of NO for inhibiting biofilms in chronic lung infections. It discusses how abnormal levels of NO in the airways contribute to chronic infections in cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), and primary ciliary dyskinesia (PCD) patients and why exogenous NO can be a promising antibiofilm strategy in clinical settings, as well as current and potential in vivo NO delivery methods. KEY POINTS : • The relationship between abnormal NO levels and biofilm development in lungs • The antibiofilm property of NO and current applications in lungs • Potential NO delivery methods and research directions in the future.
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Affiliation(s)
- Yu-Ming Cai
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
| | - Ying-Dan Zhang
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518000, China
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518000, China.
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14
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Liu Y, Tong Z, Shi J, Li R, Upton M, Wang Z. Drug repurposing for next-generation combination therapies against multidrug-resistant bacteria. Theranostics 2021; 11:4910-4928. [PMID: 33754035 PMCID: PMC7978324 DOI: 10.7150/thno.56205] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
Antimicrobial resistance has been a global health challenge that threatens our ability to control and treat life-threatening bacterial infections. Despite ongoing efforts to identify new drugs or alternatives to antibiotics, no new classes of antibiotic or their alternatives have been clinically approved in the last three decades. A combination of antibiotics and non-antibiotic compounds that could inhibit bacterial resistance determinants or enhance antibiotic activity offers a sustainable and effective strategy to confront multidrug-resistant bacteria. In this review, we provide a brief overview of the co-evolution of antibiotic discovery and the development of bacterial resistance. We summarize drug-drug interactions and uncover the art of repurposing non-antibiotic drugs as potential antibiotic adjuvants, including discussing classification and mechanisms of action, as well as reporting novel screening platforms. A pathogen-by-pathogen approach is then proposed to highlight the critical value of drug repurposing and its therapeutic potential. Finally, general advantages, challenges and development trends of drug combination strategy are discussed.
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Affiliation(s)
- Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Ziwen Tong
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Jingru Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Ruichao Li
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu, China
| | - Mathew Upton
- School of Biomedical Sciences, University of Plymouth, Drake Circus, Plymouth, UK
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
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15
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The effects of calcium–silicate–hydrate (C–S–H) seeds on reference microorganisms. APPLIED NANOSCIENCE 2020. [DOI: 10.1007/s13204-020-01347-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AbstractBuilding materials are constantly improved with various additives and admixtures in order to achieve goals ranging from obtaining increased durability or antimicrobial activity up to reducing the carbon footprint left by the cement production. Since nanomaterials were proposed for cement products, many studies explored the possibilities for their incorporation. One of the novel trends in studying these materials is evaluating their impact on living organisms, with the focus not only on toxicology but also on the application potential. Therefore, in this study, we investigated the effects of three types of calcium–silicate–hydrate (C–S–H) seeds on reference microorganisms in the scope of their basic physiology and primary metabolism. Shape, size and elemental composition of C–S–H seeds were also evaluated. The tests on the reference microorganisms have shown that the reaction to these nanomaterials can be specific and depends on the strain as well as the type of used nanomaterial. Furthermore, the presence of C–S–H seeds in the growth environment led to metabolic stimulation that resulted in faster growth, higher biochemical activity, and increased biofilm formation. Based on our findings, we conclude that even though C–S–H seeds have antimicrobial potential, they can be potentially used to promote the growth of selected microbial strains. This phenomenon could be further investigated towards the formation of beneficial biofilms on building materials.
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16
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Campos Calero G, Caballero Gómez N, Lavilla Lerma L, Benomar N, Knapp CW, Abriouel H. In silico mapping of microbial communities and stress responses in a porcine slaughterhouse and pork products through its production chain, and the efficacy of HLE disinfectant. Food Res Int 2020; 136:109486. [PMID: 32846568 DOI: 10.1016/j.foodres.2020.109486] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 01/10/2023]
Abstract
The use of shotgun metagenomic sequencing to understand ecological-level spread of microbes and their genes has provided new insights for the prevention, surveillance and control of microbial contaminants in the slaughterhouse environment. Here, microbial samples were collected from products and surrounding areas though a porcine slaughter process; shotgun metagenomic DNA-sequencing of these samples revealed a high community diversity within the porcine slaughterhouse and pork products, in zones originating from animal arrival through to the sale zones. Bacteria were more prevalent in the first zones, such as arrival- and anesthesia-zones, and DNA viruses were prevalent in the scorching-and-whip zone, animal products and sale zone. Data revealed the dominance of Firmicutes and Proteobacteria phyla followed by Actinobacteria, with a clear shift in the relative abundance of lactic acid bacteria (mainly Lactobacillus sp.) from early slaughtering steps to Proteobacteria and then to viruses suggesting site-specific community compositions occur in the slaughterhouse. Porcine-type-C oncovirus was the main virus found in slaughterhouse, which causes malignant diseases in animals and humans. As such, to guarantee food safety in a slaughterhouse, a better decipher of ecology and adaptation strategies of microbes becomes crucial. Analysis of functional genes further revealed high abundance of diverse genes associated with stress, especially in early zones (animal and environmental surfaces of arrival zone with 57,710 and 40,806 genes, respectively); SOS responsive genes represented the most prevalent, possibly associated with genomic changes responsible of biofilm formation, stringent response, heat shock, antimicrobial production and antibiotic response. The presence of several antibiotic resistance genes suggests horizontal gene transfer, thus increasing the likelihood for resistance selection in human pathogens. These findings are of great concern, with the suggestion to focus control measures and establish good disinfection strategies to avoid gene spread and microbial contaminants (bacteria and viruses) from the animal surface into the food chain and environment, which was achieved by applying HLE disinfectant after washing with detergent.
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Affiliation(s)
- Guillermo Campos Calero
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain
| | - Natacha Caballero Gómez
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain
| | - Leyre Lavilla Lerma
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain
| | - Nabil Benomar
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain
| | - Charles W Knapp
- Centre for Water, Environment, Sustainability & Public Health, Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, Scotland, United Kingdom
| | - Hikmate Abriouel
- Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain.
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17
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Merrikh H, Kohli RM. Targeting evolution to inhibit antibiotic resistance. FEBS J 2020; 287:4341-4353. [PMID: 32434280 DOI: 10.1111/febs.15370] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 03/31/2020] [Accepted: 05/15/2020] [Indexed: 12/21/2022]
Abstract
Drug-resistant bacterial infections have led to a global health crisis. Although much effort is placed on the development of new antibiotics or variants that are less subject to existing resistance mechanisms, history shows that this strategy by itself is unlikely to solve the problem of drug resistance. Here, we discuss inhibiting evolution as a strategy that, in combination with antibiotics, may resolve the problem. Although mutagenesis is the main driver of drug resistance development, attacking the drivers of genetic diversification in pathogens has not been well explored. Bacteria possess active mechanisms that increase the rate of mutagenesis, especially at times of stress, such as during replication within eukaryotic host cells, or exposure to antibiotics. We highlight how the existence of these promutagenic proteins (evolvability factors) presents an opportunity that can be capitalized upon for the effective inhibition of drug resistance development. To help move this idea from concept to execution, we first describe a set of criteria that an 'optimal' evolvability factor would likely have to meet to be a viable therapeutic target. We then discuss the intricacies of some of the known mutagenic mechanisms and evaluate their potential as drug targets to inhibit evolution. In principle, and as suggested by recent studies, we argue that the inhibition of these and other evolvability factors should reduce resistance development. Finally, we discuss the challenges of transitioning anti-evolution drugs from the laboratory to the clinic.
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Affiliation(s)
- Houra Merrikh
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Rahul M Kohli
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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18
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Marx P, Sang Y, Qin H, Wang Q, Guo R, Pfeifer C, Kreth J, Merritt J. Environmental stress perception activates structural remodeling of extant Streptococcus mutans biofilms. NPJ Biofilms Microbiomes 2020; 6:17. [PMID: 32221309 PMCID: PMC7101444 DOI: 10.1038/s41522-020-0128-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/12/2020] [Indexed: 01/28/2023] Open
Abstract
Transcription regulators from the LexA-like Protein Superfamily control a highly diverse assortment of genetic pathways in response to environmental stress. All characterized members of this family modulate their functionality and stability via a strict coordination with the coprotease function of RecA. Using the LexA-like protein IrvR from Streptococcus mutans, we demonstrate an exception to the RecA paradigm and illustrate how this evolutionary innovation has been coopted to diversify the stress responsiveness of S. mutans biofilms. Using a combination of genetics and biophysical measurements, we demonstrate how non-SOS stresses and SOS stresses each trigger separate regulatory mechanisms that stimulate production of a surface lectin responsible for remodeling the viscoelastic properties of extant biofilms during episodes of environmental stress. These studies demonstrate how changes in the external environment or even anti-biofilm therapeutic agents can activate biofilm-specific adaptive mechanisms responsible for bolstering the integrity of established biofilm communities. Such changes in biofilm community structure are likely to play central roles in the notorious recalcitrance of biofilm infections.
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Affiliation(s)
- Patrick Marx
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Yu Sang
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Hua Qin
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Qingjing Wang
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Rongkai Guo
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Carmem Pfeifer
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA
| | - Jens Kreth
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA ,0000 0000 9758 5690grid.5288.7Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239 USA
| | - Justin Merritt
- 0000 0000 9758 5690grid.5288.7Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239 USA ,0000 0000 9758 5690grid.5288.7Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239 USA
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19
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Recacha E, Machuca J, Díaz-Díaz S, García-Duque A, Ramos-Guelfo M, Docobo-Pérez F, Blázquez J, Pascual A, Rodríguez-Martínez JM. Suppression of the SOS response modifies spatiotemporal evolution, post-antibiotic effect, bacterial fitness and biofilm formation in quinolone-resistant Escherichia coli. J Antimicrob Chemother 2020; 74:66-73. [PMID: 30329046 DOI: 10.1093/jac/dky407] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/10/2018] [Indexed: 01/24/2023] Open
Abstract
Background Suppression of the SOS response has been proposed as a therapeutic strategy for potentiating quinolones against susceptible, low-level quinolone-resistant (LLQR) and resistant Enterobacteriaceae. Objectives To monitor the functionality of the SOS response in the evolution towards clinical quinolone resistance and study its impact on the evolution of spatiotemporal resistance. Methods An isogenic collection of Escherichia coli (derived from the strain ATCC 25922) carrying combinations of chromosomally and plasmid-mediated quinolone resistance mechanisms (including susceptible, LLQR and resistant phenotypes) and exhibiting a spectrum of SOS activity was used. Relevant clinical parameters such as mutation rate, mutant prevention concentration (MPC), bacterial fitness, biofilm formation and post-antibiotic effect (PAE) were evaluated. Results Inactivating the SOS response (recA deletion) led to a decrease in mutation rate (∼103 fold) in LLQR compared with WT strains at ciprofloxacin concentrations of 1 mg/L (the EUCAST breakpoint for resistance) and 2.5 mg/L (Cmax), as well as a remarkable delay in the spatiotemporal evolution of quinolone resistance. For all strains, there was an 8-fold decrease in MPC in RecA-deficient strains, with values for LLQR strains decreasing below the Cmax of ciprofloxacin. Inactivation of the SOS response reduced competitive fitness by 33%-50%, biofilm production by 22%-80% and increased the PAE by ∼3-4 h at sub-MIC concentrations of ciprofloxacin. Conclusions Our data indicate that suppression of the SOS response affects key bacterial traits and is a promising strategy for reversing and tackling the evolution of antibiotic resistance in E. coli, including low-level and resistant phenotypes at therapeutic quinolone concentrations.
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Affiliation(s)
- E Recacha
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Seville, Spain
| | - J Machuca
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Seville, Spain
| | - S Díaz-Díaz
- Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Biomedicina de Sevilla IBIS, Hospital Universitario Virgen Macarena/CSIC/Departamento de Microbiología, Universidad de Sevilla, Seville, Spain
| | - A García-Duque
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Seville, Spain
| | - M Ramos-Guelfo
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Seville, Spain
| | - F Docobo-Pérez
- Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Biomedicina de Sevilla IBIS, Hospital Universitario Virgen Macarena/CSIC/Departamento de Microbiología, Universidad de Sevilla, Seville, Spain
| | - J Blázquez
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - A Pascual
- Unidad Clínica de Enfermedades Infecciosas, Microbiología y Medicina Preventiva, Hospital Universitario Virgen Macarena, Seville, Spain.,Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Biomedicina de Sevilla IBIS, Hospital Universitario Virgen Macarena/CSIC/Departamento de Microbiología, Universidad de Sevilla, Seville, Spain
| | - J M Rodríguez-Martínez
- Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Biomedicina de Sevilla IBIS, Hospital Universitario Virgen Macarena/CSIC/Departamento de Microbiología, Universidad de Sevilla, Seville, Spain
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20
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Jin Y, Zheng H, Ibanez ACS, Patil PD, Lv S, Luo M, Duncan TM, Luk YY. Cell-Wall-Targeting Antibiotics Cause Lag-Phase Bacteria to Form Surface-Mediated Filaments Promoting the Formation of Biofilms and Aggregates. Chembiochem 2019; 21:825-835. [PMID: 31553819 DOI: 10.1002/cbic.201900508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Indexed: 01/01/2023]
Abstract
Antibiotics are known to promote bacterial formation of enhanced biofilms, the mechanism of which is not well understood. Here, using biolayer interferometry, we have shown that bacterial cultures containing antibiotics that target cell walls cause biomass deposition on surfaces over time with a linear profile rather than the Langmuir-like profiles exhibited by bacterial adherence in the absence of antibiotics. We observed about three times the initial rate and 12 times the final biomass deposition on surfaces for cultures containing carbenicillin than without. Unexpectedly, in the presence of antibiotics, the rate of biomass deposition inversely correlated with bacterial densities from different stages of a culture. Detailed studies revealed that carbenicillin caused faster growth of filaments that were seeded on surfaces from young bacteria (from lag phase) than those from high-density fast-growing bacteria, with rates of filament elongation of about 0.58 and 0.13 μm min-1 , respectively. With surfaces that do not support bacterial adherence, few filaments were observed even in solution. These filaments aggregated in solution and formed increased amounts of biofilms on surfaces. These results reveal the lifestyle of antibiotic-induced filamentous bacteria, as well as one way in which the antibiotics promote biofilm formation.
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Affiliation(s)
- Yuchen Jin
- Department of Chemistry, Syracuse University, 1-014 Center of Science and Technology, Syracuse, NY, 13244-4100, USA
| | - Hewen Zheng
- Department of Chemistry, Syracuse University, 1-014 Center of Science and Technology, Syracuse, NY, 13244-4100, USA
| | - Arizza Chiara S Ibanez
- Department of Chemistry, Syracuse University, 1-014 Center of Science and Technology, Syracuse, NY, 13244-4100, USA
| | - Pankaj D Patil
- Department of Chemistry, Syracuse University, 1-014 Center of Science and Technology, Syracuse, NY, 13244-4100, USA
| | - Suqi Lv
- Department of Chemistry, Syracuse University, 1-014 Center of Science and Technology, Syracuse, NY, 13244-4100, USA
| | - Minrui Luo
- Department of Chemistry, Syracuse University, 1-014 Center of Science and Technology, Syracuse, NY, 13244-4100, USA
| | - Thomas M Duncan
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA
| | - Yan-Yeung Luk
- Department of Chemistry, Syracuse University, 1-014 Center of Science and Technology, Syracuse, NY, 13244-4100, USA
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21
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The SOS Response Mediates Sustained Colonization of the Mammalian Gut. Infect Immun 2019; 87:IAI.00711-18. [PMID: 30510108 DOI: 10.1128/iai.00711-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/26/2018] [Indexed: 12/12/2022] Open
Abstract
Bacteria have a remarkable ability to survive, persist, and ultimately adapt to environmental challenges. A ubiquitous environmental hazard is DNA damage, and most bacteria have evolved a network of genes to combat genotoxic stress. This network is known as the SOS response and aids in bacterial survival by regulating genes involved in DNA repair and damage tolerance. Recently, the SOS response has been shown to play an important role in bacterial pathogenesis, and yet the role of the SOS response in nonpathogenic organisms and in physiological settings remains underexplored. Using a commensal Escherichia coli strain, MP1, we showed that the SOS response plays a vital role during colonization of the murine gut. In an unperturbed environment, the SOS-off mutant is impaired for stable colonization relative to a wild-type strain, suggesting the presence of genotoxic stress in the mouse gut. We evaluated the possible origins of genotoxic stress in the mouse gut by examining factors associated with the host versus the competing commensal organisms. In a dextran sulfate sodium (DSS) colitis model, the SOS-off colonization defect persisted but was not exacerbated. In contrast, in a germ-free model, the SOS-off mutant colonized with efficiency equal to that seen with the wild-type strain, suggesting that competing commensal organisms might be a significant source of genotoxic stress. This report extends our understanding of the importance of a functional SOS response for bacterial fitness in the context of a complex physiological environment and highlights the SOS response as a possible mechanism that contributes to ongoing genomic changes, including potential antibiotic resistance, in the microbiome of healthy hosts.
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22
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Selwood T, Larsen BJ, Mo CY, Culyba MJ, Hostetler ZM, Kohli RM, Reitz AB, Baugh SDP. Advancement of the 5-Amino-1-(Carbamoylmethyl)-1H-1,2,3-Triazole-4-Carboxamide Scaffold to Disarm the Bacterial SOS Response. Front Microbiol 2018; 9:2961. [PMID: 30619111 PMCID: PMC6305444 DOI: 10.3389/fmicb.2018.02961] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 11/16/2018] [Indexed: 12/16/2022] Open
Abstract
Many antibiotics, either directly or indirectly, cause DNA damage thereby activating the bacterial DNA damage (SOS) response. SOS activation results in expression of genes involved in DNA repair and mutagenesis, and the regulation of the SOS response relies on two key proteins, LexA and RecA. Genetic studies have indicated that inactivating the regulatory proteins of this response sensitizes bacteria to antibiotics and slows the appearance of resistance. However, advancement of small molecule inhibitors of the SOS response has lagged, despite their clear promise in addressing the threat of antibiotic resistance. Previously, we had addressed this deficit by performing a high throughput screen of ∼1.8 million compounds that monitored for inhibition of RecA-mediated auto-proteolysis of Escherichia coli LexA, the reaction that initiates the SOS response. In this report, the refinement of the 5-amino-1-(carbamoylmethyl)-1H-1,2,3-triazole-4-carboxamide scaffold identified in the screen is detailed. After development of a modular synthesis, a survey of key activity determinants led to the identification of an analog with improved potency and increased breadth, targeting auto-proteolysis of LexA from both E. coli and Pseudomonas aeruginosa. Comparison of the structure of this compound to those of others in the series suggests structural features that may be required for activity and cross-species breadth. In addition, the feasibility of small molecule modulation of the SOS response was demonstrated in vivo by the suppression of the appearance of resistance. These structure activity relationships thus represent an important step toward producing Drugs that Inhibit SOS Activation to Repress Mechanisms Enabling Resistance (DISARMERs).
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Affiliation(s)
- Trevor Selwood
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, United States
| | - Brian J Larsen
- Fox Chase Chemical Diversity Center, Inc., Doylestown, PA, United States
| | - Charlie Y Mo
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, United States
| | - Matthew J Culyba
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, United States
| | - Zachary M Hostetler
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, United States
| | - Rahul M Kohli
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, United States
| | - Allen B Reitz
- Fox Chase Chemical Diversity Center, Inc., Doylestown, PA, United States
| | - Simon D P Baugh
- Fox Chase Chemical Diversity Center, Inc., Doylestown, PA, United States
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23
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Cyclic di-GMP Positively Regulates DNA Repair in Vibrio cholerae. J Bacteriol 2018; 200:JB.00005-18. [PMID: 29610212 DOI: 10.1128/jb.00005-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 03/27/2018] [Indexed: 12/21/2022] Open
Abstract
In Vibrio cholerae, high intracellular cyclic di-GMP (c-di-GMP) concentration are associated with a biofilm lifestyle, while low intracellular c-di-GMP concentrations are associated with a motile lifestyle. c-di-GMP also regulates other behaviors, such as acetoin production and type II secretion; however, the extent of phenotypes regulated by c-di-GMP is not fully understood. We recently determined that the sequence upstream of the DNA repair gene encoding 3-methyladenine glycosylase (tag) was positively induced by c-di-GMP, suggesting that this signaling system might impact DNA repair pathways. We identified a DNA region upstream of tag that is required for transcriptional induction by c-di-GMP. We further showed that c-di-GMP induction of tag expression was dependent on the c-di-GMP-dependent biofilm regulators VpsT and VpsR. In vitro binding assays and heterologous host expression studies show that VpsT acts directly at the tag promoter in response to c-di-GMP to induce tag expression. Last, we determined that strains with high c-di-GMP concentrations are more tolerant of the DNA-damaging agent methyl methanesulfonate. Our results indicate that the regulatory network of c-di-GMP in V. cholerae extends beyond biofilm formation and motility to regulate DNA repair through the VpsR/VpsT c-di-GMP-dependent cascade.IMPORTANCEVibrio cholerae is a prominent human pathogen that is currently causing a pandemic outbreak in Haiti, Yemen, and Ethiopia. The second messenger molecule cyclic di-GMP (c-di-GMP) mediates the transitions in V. cholerae between a sessile biofilm-forming state and a motile lifestyle, both of which are important during V. cholerae environmental persistence and human infections. Here, we report that in V. cholerae c-di-GMP also controls DNA repair. We elucidate the regulatory pathway by which c-di-GMP increases DNA repair, allowing this bacterium to tolerate high concentrations of mutagens at high intracellular levels of c-di-GMP. Our work suggests that DNA repair and biofilm formation may be linked in V. cholerae.
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24
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Tkachenko AG. Stress Responses of Bacterial Cells as Mechanism of Development of Antibiotic Tolerance (Review). APPL BIOCHEM MICRO+ 2018. [DOI: 10.1134/s0003683818020114] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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25
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Mo CY, Culyba MJ, Selwood T, Kubiak JM, Hostetler ZM, Jurewicz AJ, Keller PM, Pope AJ, Quinn A, Schneck J, Widdowson KL, Kohli RM. Inhibitors of LexA Autoproteolysis and the Bacterial SOS Response Discovered by an Academic-Industry Partnership. ACS Infect Dis 2018; 4:349-359. [PMID: 29275629 DOI: 10.1021/acsinfecdis.7b00122] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The RecA/LexA axis of the bacterial DNA damage (SOS) response is a promising, yet nontraditional, drug target. The SOS response is initiated upon genotoxic stress, when RecA, a DNA damage sensor, induces LexA, the SOS repressor, to undergo autoproteolysis, thereby derepressing downstream genes that can mediate DNA repair and accelerate mutagenesis. As genetic inhibition of the SOS response sensitizes bacteria to DNA damaging antibiotics and decreases acquired resistance, inhibitors of the RecA/LexA axis could potentiate our current antibiotic arsenal. Compounds targeting RecA, which has many mammalian homologues, have been reported; however, small-molecules targeting LexA autoproteolysis, a reaction unique to the prokaryotic SOS response, have remained elusive. Here, we describe the logistics and accomplishments of an academic-industry partnership formed to pursue inhibitors against the RecA/LexA axis. A novel fluorescence polarization assay reporting on RecA-induced self-cleavage of LexA enabled the screening of 1.8 million compounds. Follow-up studies on select leads show distinct activity patterns in orthogonal assays, including several with activity in cell-based assays reporting on SOS activation. Mechanistic assays demonstrate that we have identified first-in-class small molecules that specifically target the LexA autoproteolysis step in SOS activation. Our efforts establish a realistic example for navigating academic-industry partnerships in pursuit of anti-infective drugs and offer starting points for dedicated lead optimization of SOS inhibitors that could act as adjuvants for current antibiotics.
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Affiliation(s)
- Charlie Y. Mo
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Matthew J. Culyba
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Trevor Selwood
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Jeffrey M. Kubiak
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Zachary M. Hostetler
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Anthony J. Jurewicz
- Screening, Profiling, and Mechanistic Biology, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Paul M. Keller
- Screening, Profiling, and Mechanistic Biology, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Andrew J. Pope
- Discovery Partnerships with Academia, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Amy Quinn
- Screening, Profiling, and Mechanistic Biology, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Jessica Schneck
- Screening, Profiling, and Mechanistic Biology, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Katherine L. Widdowson
- Discovery Partnerships with Academia, GlaxoSmithKline, 1250 S. Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Rahul M. Kohli
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
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Alam MK, Alhhazmi A, DeCoteau JF, Luo Y, Geyer CR. RecA Inhibitors Potentiate Antibiotic Activity and Block Evolution of Antibiotic Resistance. Cell Chem Biol 2016; 23:381-91. [PMID: 26991103 DOI: 10.1016/j.chembiol.2016.02.010] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 02/02/2016] [Accepted: 02/19/2016] [Indexed: 11/25/2022]
Abstract
Antibiotic resistance arises from the maintenance of resistance mutations or genes acquired from the acquisition of adaptive de novo mutations or the transfer of resistance genes. Antibiotic resistance is acquired in response to antibiotic therapy by activating SOS-mediated DNA repair and mutagenesis and horizontal gene transfer pathways. Initiation of the SOS pathway promotes activation of RecA, inactivation of LexA repressor, and induction of SOS genes. Here, we have identified and characterized phthalocyanine tetrasulfonic acid RecA inhibitors that block antibiotic-induced activation of the SOS response. These inhibitors potentiate the activity of bactericidal antibiotics, including members of the quinolone, β-lactam, and aminoglycoside families in both Gram-negative and Gram-positive bacteria. They reduce the ability of bacteria to acquire antibiotic resistance mutations and to transfer mobile genetic elements conferring resistance. This study highlights the advantage of including RecA inhibitors in bactericidal antibiotic therapies and provides a new strategy for prolonging antibiotic shelf life.
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Affiliation(s)
- Md Kausar Alam
- Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Areej Alhhazmi
- Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - John F DeCoteau
- Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Yu Luo
- Department of Biochemistry, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - C Ronald Geyer
- Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
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Michiels JE, Van den Bergh B, Verstraeten N, Michiels J. Molecular mechanisms and clinical implications of bacterial persistence. Drug Resist Updat 2016; 29:76-89. [PMID: 27912845 DOI: 10.1016/j.drup.2016.10.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Any bacterial population harbors a small number of phenotypic variants that survive exposure to high concentrations of antibiotic. Importantly, these so-called 'persister cells' compromise successful antibiotic therapy of bacterial infections and are thought to contribute to the development of antibiotic resistance. Intriguingly, drug-tolerant persisters have also been identified as a factor underlying failure of chemotherapy in tumor cell populations. Recent studies have begun to unravel the complex molecular mechanisms underlying persister formation and revolve around stress responses and toxin-antitoxin modules. Additionally, in vitro evolution experiments are revealing insights into the evolutionary and adaptive aspects of this phenotype. Furthermore, ever-improving experimental techniques are stimulating efforts to investigate persisters in their natural, infection-associated, in vivo environment. This review summarizes recent insights into the molecular mechanisms of persister formation, explains how persisters complicate antibiotic treatment of infections, and outlines emerging strategies to combat these tolerant cells.
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Affiliation(s)
| | | | | | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.
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28
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Streptomycin favors biofilm formation by altering cell surface properties. Appl Microbiol Biotechnol 2016; 100:8843-53. [DOI: 10.1007/s00253-016-7793-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/03/2016] [Indexed: 10/21/2022]
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Systematically Altering Bacterial SOS Activity under Stress Reveals Therapeutic Strategies for Potentiating Antibiotics. mSphere 2016; 1:mSphere00163-16. [PMID: 27536734 PMCID: PMC4980697 DOI: 10.1128/msphere.00163-16] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 07/19/2016] [Indexed: 11/20/2022] Open
Abstract
Our antibiotic arsenal is becoming depleted, in part, because bacteria have the ability to rapidly adapt and acquire resistance to our best agents. The SOS pathway, a widely conserved DNA damage stress response in bacteria, is activated by many antibiotics and has been shown to play central role in promoting survival and the evolution of resistance under antibiotic stress. As a result, targeting the SOS response has been proposed as an adjuvant strategy to revitalize our current antibiotic arsenal. However, the optimal molecular targets and partner antibiotics for such an approach remain unclear. In this study, focusing on the two key regulators of the SOS response, LexA and RecA, we provide the first comprehensive assessment of how to target the SOS response in order to increase bacterial susceptibility and reduce mutagenesis under antibiotic treatment. The bacterial SOS response is a DNA damage repair network that is strongly implicated in both survival and acquired drug resistance under antimicrobial stress. The two SOS regulators, LexA and RecA, have therefore emerged as potential targets for adjuvant therapies aimed at combating resistance, although many open questions remain. For example, it is not well understood whether SOS hyperactivation is a viable therapeutic approach or whether LexA or RecA is a better target. Furthermore, it is important to determine which antimicrobials could serve as the best treatment partners with SOS-targeting adjuvants. Here we derived Escherichia coli strains that have mutations in either lexA or recA genes in order to cover the full spectrum of possible SOS activity levels. We then systematically analyzed a wide range of antimicrobials by comparing the mean inhibitory concentrations (MICs) and induced mutation rates for each drug-strain combination. We first show that significant changes in MICs are largely confined to DNA-damaging antibiotics, with strains containing a constitutively repressed SOS response impacted to a greater extent than hyperactivated strains. Second, antibiotic-induced mutation rates were suppressed when SOS activity was reduced, and this trend was observed across a wider spectrum of antibiotics. Finally, perturbing either LexA or RecA proved to be equally viable strategies for targeting the SOS response. Our work provides support for multiple adjuvant strategies, while also suggesting that the combination of an SOS inhibitor with a DNA-damaging antibiotic could offer the best potential for lowering MICs and decreasing acquired drug resistance. IMPORTANCE Our antibiotic arsenal is becoming depleted, in part, because bacteria have the ability to rapidly adapt and acquire resistance to our best agents. The SOS pathway, a widely conserved DNA damage stress response in bacteria, is activated by many antibiotics and has been shown to play central role in promoting survival and the evolution of resistance under antibiotic stress. As a result, targeting the SOS response has been proposed as an adjuvant strategy to revitalize our current antibiotic arsenal. However, the optimal molecular targets and partner antibiotics for such an approach remain unclear. In this study, focusing on the two key regulators of the SOS response, LexA and RecA, we provide the first comprehensive assessment of how to target the SOS response in order to increase bacterial susceptibility and reduce mutagenesis under antibiotic treatment.
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SOS System Induction Inhibits the Assembly of Chemoreceptor Signaling Clusters in Salmonella enterica. PLoS One 2016; 11:e0146685. [PMID: 26784887 PMCID: PMC4718596 DOI: 10.1371/journal.pone.0146685] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/21/2015] [Indexed: 01/08/2023] Open
Abstract
Swarming, a flagellar-driven multicellular form of motility, is associated with bacterial virulence and increased antibiotic resistance. In this work we demonstrate that activation of the SOS response reversibly inhibits swarming motility by preventing the assembly of chemoreceptor-signaling polar arrays. We also show that an increase in the concentration of the RecA protein, generated by SOS system activation, rather than another function of this genetic network impairs chemoreceptor polar cluster formation. Our data provide evidence that the molecular balance between RecA and CheW proteins is crucial to allow polar cluster formation in Salmonella enterica cells. Thus, activation of the SOS response by the presence of a DNA-injuring compound increases the RecA concentration, thereby disturbing the equilibrium between RecA and CheW and resulting in the cessation of swarming. Nevertheless, when the DNA-damage decreases and the SOS response is no longer activated, basal RecA levels and thus polar cluster assembly are reestablished. These results clearly show that bacterial populations moving over surfaces make use of specific mechanisms to avoid contact with DNA-damaging compounds.
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The SOS Response Master Regulator LexA Is Associated with Sporulation, Motility and Biofilm Formation in Clostridium difficile. PLoS One 2015; 10:e0144763. [PMID: 26682547 PMCID: PMC4689574 DOI: 10.1371/journal.pone.0144763] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 11/22/2015] [Indexed: 01/05/2023] Open
Abstract
The LexA regulated SOS network is a bacterial response to DNA damage of metabolic or environmental origin. In Clostridium difficile, a nosocomial pathogen causing a range of intestinal diseases, the in-silico deduced LexA network included the core SOS genes involved in the DNA repair and genes involved in various other biological functions that vary among different ribotypes. Here we describe the construction and characterization of a lexA ClosTron mutant in C. difficile R20291 strain. The mutation of lexA caused inhibition of cell division resulting in a filamentous phenotype. The lexA mutant also showed decreased sporulation, a reduction in swimming motility, greater sensitivity to metronidazole, and increased biofilm formation. Changes in the regulation of toxin A, but not toxin B, were observed in the lexA mutant in the presence of sub-inhibitory concentrations of levofloxacin. C. difficile LexA is, therefore, not only a regulator of DNA damage but also controls many biological functions associated with virulence.
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Abstract
![]()
Bacteria
possess a remarkable ability to rapidly adapt and evolve
in response to antibiotics. Acquired antibiotic resistance can arise
by multiple mechanisms but commonly involves altering the target site
of the drug, enzymatically inactivating the drug, or preventing the
drug from accessing its target. These mechanisms involve new genetic
changes in the pathogen leading to heritable resistance. This recognition
underscores the importance of understanding how such
genetic changes can arise. Here, we review recent advances in our
understanding of the processes that contribute to the evolution of
antibiotic resistance, with a particular focus on hypermutation mediated
by the SOS pathway and horizontal gene transfer. We explore the molecular
mechanisms involved in acquired resistance and discuss their viability
as potential targets. We propose that additional studies into these
adaptive mechanisms not only can provide insights into evolution but
also can offer a strategy for potentiating our current antibiotic
arsenal.
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33
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Involvement of stress-related genes polB and PA14_46880 in biofilm formation of Pseudomonas aeruginosa. Infect Immun 2014; 82:4746-57. [PMID: 25156741 DOI: 10.1128/iai.01915-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chronic infections of Pseudomonas aeruginosa are generally established through production of biofilm. During biofilm formation, production of an extracellular matrix and establishment of a distinct bacterial phenotype make these infections difficult to eradicate. However, biofilm studies have been hampered by the fact that most assays utilize nonliving surfaces as biofilm attachment substrates. In an attempt to better understand the mechanisms behind P. aeruginosa biofilm formation, we performed a genetic screen to identify novel factors involved in biofilm formation on biotic and abiotic surfaces. We found that deletion of genes polB and PA14_46880 reduced biofilm formation significantly compared to that in the wild-type strain PA14 in an abiotic biofilm system. In a biotic biofilm model, wherein biofilms form on cultured airway cells, the ΔpolB and ΔPA14_46880 strains showed increased cytotoxic killing of the airway cells independent of the total number of bacteria bound. Notably, deletion mutant strains were more resistant to ciprofloxacin treatment. This phenotype was linked to decreased expression of algR, an alginate transcriptional regulatory gene, under ciprofloxacin pressure. Moreover, we found that pyocyanin production was increased in planktonic cells of mutant strains. These results indicate that inactivation of polB and PA14_46880 may inhibit transition of P. aeruginosa from a more acute infection lifestyle to the biofilm phenotype. Future investigation of these genes may lead to a better understanding of P. aeruginosa biofilm formation and chronic biofilm infections.
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34
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Costa SB, Campos ACC, Pereira ACM, de Mattos-Guaraldi AL, Júnior RH, Rosa ACP, Asad LMBO. Adherence to abiotic surface induces SOS response in Escherichia coli K-12 strains under aerobic and anaerobic conditions. MICROBIOLOGY-SGM 2014; 160:1964-1973. [PMID: 25012969 DOI: 10.1099/mic.0.075317-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the oxygen tension. In conclusion, it was proven that bacterial interaction with abiotic surfaces can lead to SOS induction and associated filamentation. Moreover, we verified that endonuclease V is involved in biofilm formation.
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Affiliation(s)
- Suelen B Costa
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Brazil
| | - Ana Carolina C Campos
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Brazil
| | - Ana Claudia M Pereira
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Brazil
| | - Ana Luiza de Mattos-Guaraldi
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Brazil
| | - Raphael Hirata Júnior
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Brazil
| | - Ana Cláudia P Rosa
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Brazil
| | - Lídia M B O Asad
- Departamento de Biofísica e Biometria, Instituto de Biologia Roberto Alcântara Gomes, Universidade do Estado do Rio de Janeiro, Brazil
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35
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Baharoglu Z, Mazel D. SOS, the formidable strategy of bacteria against aggressions. FEMS Microbiol Rev 2014; 38:1126-45. [PMID: 24923554 DOI: 10.1111/1574-6976.12077] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 05/01/2014] [Accepted: 05/07/2014] [Indexed: 12/22/2022] Open
Abstract
The presence of an abnormal amount of single-stranded DNA in the bacterial cell constitutes a genotoxic alarm signal that induces the SOS response, a broad regulatory network found in most bacterial species to address DNA damage. The aim of this review was to point out that beyond being a repair process, SOS induction leads to a very strong but transient response to genotoxic stress, during which bacteria can rearrange and mutate their genome, induce several phenotypic changes through differential regulation of genes, and sometimes acquire characteristics that potentiate bacterial survival and adaptation to changing environments. We review here the causes and consequences of SOS induction, but also how this response can be modulated under various circumstances and how it is connected to the network of other important stress responses. In the first section, we review articles describing the induction of the SOS response at the molecular level. The second section discusses consequences of this induction in terms of DNA repair, changes in the genome and gene expression, and sharing of genomic information, with their effects on the bacteria's life and evolution. The third section is about the fine tuning of this response to fit with the bacteria's 'needs'. Finally, we discuss recent findings linking the SOS response to other stress responses. Under these perspectives, SOS can be perceived as a powerful bacterial strategy against aggressions.
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Affiliation(s)
- Zeynep Baharoglu
- Institut Pasteur, Département Génomes et Génétique, Unité Plasticité du Génome Bactérien, Paris, France; CNRS, UMR3525, Paris, France
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Wolfe A, Phipps K, Weitao T. Viral and cellular SOS-regulated motor proteins: dsDNA translocation mechanisms with divergent functions. Cell Biosci 2014; 4:31. [PMID: 24995125 PMCID: PMC4080785 DOI: 10.1186/2045-3701-4-31] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 06/13/2014] [Indexed: 01/15/2023] Open
Abstract
DNA damage attacks on bacterial cells have been known to activate the SOS response, a transcriptional response affecting chromosome replication, DNA recombination and repair, cell division and prophage induction. All these functions require double-stranded (ds) DNA translocation by ASCE hexameric motors. This review seeks to delineate the structural and functional characteristics of the SOS response and the SOS-regulated DNA translocases FtsK and RuvB with the phi29 bacteriophage packaging motor gp16 ATPase as a prototype to study bacterial motors. While gp16 ATPase, cellular FtsK and RuvB are similarly comprised of hexameric rings encircling dsDNA and functioning as ATP-driven DNA translocases, they utilize different mechanisms to accomplish separate functions, suggesting a convergent evolution of these motors. The gp16 ATPase and FtsK use a novel revolution mechanism, generating a power stroke between subunits through an entropy-DNA affinity switch and pushing dsDNA inward without rotation of DNA and the motor, whereas RuvB seems to employ a rotation mechanism that remains to be further characterized. While FtsK and RuvB perform essential tasks during the SOS response, their roles may be far more significant as SOS response is involved in antibiotic-inducible bacterial vesiculation and biofilm formation as well as the perspective of the bacteria-cancer evolutionary interaction.
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Affiliation(s)
- Annie Wolfe
- Biology Department, College of Science and Mathematics, Southwest Baptist University, 1600 University Ave, Bolivar, Missouri 65613, USA
| | - Kara Phipps
- Biology Department, College of Science and Mathematics, Southwest Baptist University, 1600 University Ave, Bolivar, Missouri 65613, USA
| | - Tao Weitao
- Biology Department, College of Science and Mathematics, Southwest Baptist University, 1600 University Ave, Bolivar, Missouri 65613, USA
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Mo CY, Birdwell LD, Kohli RM. Specificity determinants for autoproteolysis of LexA, a key regulator of bacterial SOS mutagenesis. Biochemistry 2014; 53:3158-68. [PMID: 24779472 PMCID: PMC4030785 DOI: 10.1021/bi500026e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
![]()
Bacteria utilize the tightly regulated
stress response (SOS) pathway
to respond to a variety of genotoxic agents, including antimicrobials.
Activation of the SOS response is regulated by a key repressor-protease,
LexA, which undergoes autoproteolysis in the setting of stress, resulting
in derepression of SOS genes. Remarkably, genetic inactivation of
LexA’s self-cleavage activity significantly decreases acquired
antibiotic resistance in infection models and renders bacteria hypersensitive
to traditional antibiotics, suggesting that a mechanistic study of
LexA could help inform its viability as a novel target for combating
acquired drug resistance. Despite structural insights into LexA, a
detailed knowledge of the enzyme’s protease specificity is
lacking. Here, we employ saturation and positional scanning mutagenesis
on LexA’s internal cleavage region to analyze >140 mutants
and generate a comprehensive specificity profile of LexA from the
human pathogen Pseudomonas aeruginosa (LexAPa). We find that the LexAPa active site possesses a unique mode of substrate recognition.
Positions P1–P3 prefer small hydrophobic residues that suggest
specific contacts with the active site, while positions P5 and P1′
show a preference for flexible glycine residues that may facilitate
the conformational change that permits autoproteolysis. We further
show that stabilizing the β-turn within the cleavage region
enhances LexA autoproteolytic activity. Finally, we identify permissive
positions flanking the scissile bond (P4 and P2′) that are
tolerant to extensive mutagenesis. Our studies shed light on the active
site architecture of the LexA autoprotease and provide insights that
may inform the design of probes of the SOS pathway.
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Affiliation(s)
- Charlie Y Mo
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania , 3610 Hamilton Walk, Philadelphia, Pennsylvania 19014, United States
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38
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Blango MG, Ott EM, Erman A, Veranic P, Mulvey MA. Forced resurgence and targeting of intracellular uropathogenic Escherichia coli reservoirs. PLoS One 2014; 9:e93327. [PMID: 24667805 PMCID: PMC3965547 DOI: 10.1371/journal.pone.0093327] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/03/2014] [Indexed: 11/19/2022] Open
Abstract
Intracellular quiescent reservoirs of uropathogenic Escherichia coli (UPEC), which can seed the bladder mucosa during the acute phase of a urinary tract infection (UTI), are protected from antibiotic treatments and are extremely difficult to eliminate. These reservoirs are a potential source for recurrent UTIs that affect millions annually. Here, using murine infection models and the bladder cell exfoliant chitosan, we demonstrate that intracellular UPEC populations shift within the stratified layers of the urothelium during the course of a UTI. Following invasion of the terminally differentiated superficial layer of epithelial cells that line the bladder lumen, UPEC can multiply and disseminate, eventually establishing reservoirs within underlying immature host cells. If given access, UPEC can invade the superficial and immature bladder cells equally well. As infected immature host cells differentiate and migrate towards the apical surface of the bladder, UPEC can reinitiate growth and discharge into the bladder lumen. By inducing the exfoliation of the superficial layers of the urothelium, chitosan stimulates rapid regenerative processes and the reactivation and efflux of quiescent intracellular UPEC reservoirs. When combined with antibiotics, chitosan treatment significantly reduces bacterial loads within the bladder and may therefore be of therapeutic value to individuals with chronic, recurrent UTIs.
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Affiliation(s)
- Matthew G. Blango
- Division of Microbiology and Immunology, Pathology Department, University of Utah, Salt Lake City, Utah, United States of America
| | - Elizabeth M. Ott
- Division of Microbiology and Immunology, Pathology Department, University of Utah, Salt Lake City, Utah, United States of America
| | - Andreja Erman
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljublijana, Slovenia
| | - Peter Veranic
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljublijana, Slovenia
| | - Matthew A. Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Motility of Pseudomonas aeruginosa contributes to SOS-inducible biofilm formation. Res Microbiol 2013; 164:1019-27. [PMID: 24125694 DOI: 10.1016/j.resmic.2013.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 09/24/2013] [Indexed: 11/20/2022]
Abstract
DNA-damaging antibiotics such as ciprofloxacin induce biofilm formation and the SOS response through autocleavage of SOS-repressor LexA in Pseudomonas aeruginosa. However, the biofilm-SOS connection remains poorly understood. It was investigated with 96-well and lipid biofilm assays. The effects of ciprofloxacin were examined on biofilm stimulation of the SOS mutant and wild-type strains. The stimulation observed in the wild-type in which SOS was induced was reduced in the mutant in which LexA was made non-cleavable (LexAN) and thus SOS non-inducible. Therefore, the stimulation appeared to involve SOS. The possible mechanisms of inducible biofilm formation were explored by subproteomic analysis of outer membrane fractions extracted from biofilms. The data predicted an inhibitory role of LexA in flagellum function. This premise was tested first by functional and morphological analyses of flagellum-based motility. The flagellum swimming motility decreased in the LexAN strain treated with ciprofloxacin. Second, the motility-biofilm assay was performed, which tested cell migration and biofilm formation. The results showed that wild-type biofilm increased significantly over the LexAN. These results suggest that LexA repression of motility, which is the initial event in biofilm development, contributes to repression of SOS-inducible biofilm formation.
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Kovacs B, Le Gall-David S, Vincent P, Le Bars H, Buffet-Bataillon S, Bonnaure-Mallet M, Jolivet-Gougeon A. Is biofilm formation related to the hypermutator phenotype in clinical Enterobacteriaceae isolates? FEMS Microbiol Lett 2013; 347:116-22. [PMID: 23909976 DOI: 10.1111/1574-6968.12229] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/18/2013] [Accepted: 07/26/2013] [Indexed: 12/29/2022] Open
Abstract
In bacteria, complex adaptive processes are involved during transition from the planktonic to the biofilm mode of growth, and mutator strains are more prone to producing biofilms. Enterobacteriaceae species were isolated from urinary tract infections (UTIs; 222 strains) and from bloodstream infections (BSIs; 213 strains). Relationship between the hypermutable phenotype and biofilm forming capacity was investigated in these clinical strains. Mutation frequencies were estimated by monitoring the capacity of each strain to generate mutations that conferred rifampicin resistance on supplemented medium. Initiation of biofilm formation was assayed by determining the ability of the cells to adhere to a 96-well polystyrene microtitre plate. UTI Enterobacteriaceae strains showed significantly higher biofilm-forming capacity: 63.1% (54.0% for E. coli strains) vs. 42.3% for BSI strains (47.7% for E. coli). Strains isolated from UTIs did not present higher mutation frequencies than those from BSIs: contrary to what has been widely described for P. aeruginosa strains, isolated from pulmonary samples in patients suffering from cystic fibrosis, no relationship was found between the hypermutator phenotype in Enterobacteriaceae and the ability to initiate a biofilm.
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Affiliation(s)
- Bela Kovacs
- Department of Urology, Jahn Ferenc South-Pest Hospital, Budapest, Hungary
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Stalder T, Alrhmoun M, Louvet JN, Casellas M, Maftah C, Carrion C, Pons MN, Pahl O, Ploy MC, Dagot C. Dynamic assessment of the floc morphology, bacterial diversity, and integron content of an activated sludge reactor processing hospital effluent. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:7909-7917. [PMID: 23789899 DOI: 10.1021/es4008646] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The treatment of hospital effluents (HE) is a major concern, as they are suspected of disseminating drugs and antibiotic resistance determinants in the environment. In order to assess HE influence on wastewater treatment plant biomass, lab-scale conventional activated sludge systems (CAS) were continuously fed with real HE or urban effluent as a control. To gain insights into the main hurdles linked to HE treatment, we conducted a multiparameter study using classical physicochemical characterization, phase contrast and confocal laser scaning microscopy, and molecular biology (i.e., pyrosequencing) tools. HE caused erosion of floc structure and the production of extracellular polymeric substances attributed to the development of floc-forming bacteria. Adaptation of the sludge bacterial community to the HE characteristics, thus maintaining the purification performance of the biomass, was observed. Finally, the comparative metagenomic analysis of the CAS showed that HE treatment resulted in an increase of class 1 resistance integrons (RIs) and the introduction of Pseudomonas spp. into the bacterial community. HE treatment did not reduce the CAS process performance; nevertheless it increases the risk of dissemination into the environment of bacterial species and genetic determinants (RIs) involved in antibiotic resistance acquisition.
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Wang N, Trivedi P. Citrus huanglongbing: a newly relevant disease presents unprecedented challenges. PHYTOPATHOLOGY 2013; 103:652-65. [PMID: 23441969 DOI: 10.1094/phyto-12-12-0331-rvw] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Citrus huanglongbing (HLB) is one of the oldest citrus diseases and has been known for over a century. HLB is caused by 'Candidatus Liberibacter' spp. that are phloem-limited, fastidious α-proteobacteria and infect hosts in different Kingdoms (i.e., Animalia and Plantae). When compared with well-characterized, cultivatable plant-pathogenic Gram-negative bacteria, the interactions of uncultured insect-vectored plant-pathogenic bacteria, including 'Ca. Liberibacter' spp., with their hosts remain poorly understood. 'Ca. Liberibacter' spp. have been known to cause HLB, which has been rapidly spreading worldwide, resulting in dramatic economic losses. HLB presents an unprecedented challenge to citrus production. In this review, we focus on the most recent research on citrus, 'Candidatus Liberibacter asiaticus', and psyllid interactions, specifically considering the following topics: evolutionary relationships among 'Ca. Liberibacter' spp., genetic diversity, host range, genome analysis, transmission, virulence mechanisms, and the ecological importance of HLB. Currently, no efficient management strategy is available to control HLB, although some promising progress has been made. Further studies are needed to understand citrus, 'Ca. L. asiaticus', and psyllid interactions to design innovative management strategies. Although HLB has been problematic for over a century, we can only win the battle against HLB with a coordinated and deliberate effort by the citrus industry, citrus growers, researchers, legislatures, and governments.
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Affiliation(s)
- Nian Wang
- Cirtrus Research Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred 33850, USA.
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Multiple Pathways of Genome Plasticity Leading to Development of Antibiotic Resistance. Antibiotics (Basel) 2013; 2:288-315. [PMID: 27029305 PMCID: PMC4790341 DOI: 10.3390/antibiotics2020288] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 05/21/2013] [Accepted: 05/23/2013] [Indexed: 02/05/2023] Open
Abstract
The emergence of multi-resistant bacterial strains is a major source of concern and has been correlated with the widespread use of antibiotics. The origins of resistance are intensively studied and many mechanisms involved in resistance have been identified, such as exogenous gene acquisition by horizontal gene transfer (HGT), mutations in the targeted functions, and more recently, antibiotic tolerance through persistence. In this review, we focus on factors leading to integron rearrangements and gene capture facilitating antibiotic resistance acquisition, maintenance and spread. The role of stress responses, such as the SOS response, is discussed.
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Maredia R, Devineni N, Lentz P, Dallo SF, Yu J, Guentzel N, Chambers J, Arulanandam B, Haskins WE, Weitao T. Vesiculation from Pseudomonas aeruginosa under SOS. ScientificWorldJournal 2012; 2012:402919. [PMID: 22448133 PMCID: PMC3289957 DOI: 10.1100/2012/402919] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 10/23/2011] [Indexed: 11/30/2022] Open
Abstract
Bacterial infections can be aggravated by antibiotic treatment that induces SOS response and vesiculation. This leads to a hypothesis concerning association of SOS with vesiculation. To test it, we conducted multiple analyses of outer membrane vesicles (OMVs) produced from the Pseudomonas aeruginosa wild type in which SOS is induced by ciprofloxacin and from the LexA noncleavable (lexAN) strain in which SOS is repressed. The levels of OMV proteins, lipids, and cytotoxicity increased for both the treated strains, demonstrating vesiculation stimulation by the antibiotic treatment. However, the further increase was suppressed in the lexAN strains, suggesting the SOS involvement. Obviously, the stimulated vesiculation is attributed by both SOS-related and unrelated factors. OMV subproteomic analysis was performed to examine these factors, which reflected the OMV-mediated cytotoxicity and the physiology of the vesiculating cells under treatment and SOS. Thus, SOS plays a role in the vesiculation stimulation that contributes to cytotoxicity.
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Affiliation(s)
- Reshma Maredia
- Department of Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
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The role of DNA base excision repair in filamentation in Escherichia coli K-12 adhered to epithelial HEp-2 cells. Antonie van Leeuwenhoek 2011; 101:423-31. [PMID: 21965040 DOI: 10.1007/s10482-011-9649-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/20/2011] [Indexed: 12/19/2022]
Abstract
Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species generated by chemical and physical agents or by metabolism which can react with DNA and cause a variety of mutations. Epithelial cells are typically the first type of host cell to come into contact with potential microbial invaders. In this work, we have evaluated whether the adherence to human epithelial cells causes DNA damage and associated filamentation. Experiments concerning adherence to HEp-2 cells were carried out with mutants deficient in BER that were derived from Escherichia coli K-12. Since the removal of mannose during bacterial interaction with HEp-2 cells allows adhesion through mannose-sensitive adhesins, the experiments were also performed in the presence and the absence of mannose. Our results showed enhanced filamentation for the single xth (BW9091) and triple xth nfo nth (BW535) mutants in adherence assays with HEp-2 cells performed without D: -mannose. The increased filamentation growth was inhibited by complementation of BER mutants with a wild type xth gene. Moreover, we measured SOS induction of bacteria adhered to HEp-2 cells in the presence and absence of D: -mannose through of SOS-chromotest assay and we observed a higher β-galactosidase expression in the absence of mannose. In this context, data showed evidence that bacterial attachment to HEp-2 epithelial surfaces can generate DNA lesions and SOS induction.
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