51
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McCully AL, LaSarre B, McKinlay JB. Growth-independent cross-feeding modifies boundaries for coexistence in a bacterial mutualism. Environ Microbiol 2017; 19:3538-3550. [PMID: 28654212 DOI: 10.1111/1462-2920.13847] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/19/2017] [Accepted: 06/22/2017] [Indexed: 11/27/2022]
Abstract
Nutrient cross-feeding can stabilize microbial mutualisms, including those important for carbon cycling in nutrient-limited anaerobic environments. It remains poorly understood how nutrient limitation within natural environments impacts mutualist growth, cross-feeding levels and ultimately mutualism dynamics. We examined the effects of nutrient limitation within a mutualism using theoretical and experimental approaches with a synthetic anaerobic coculture pairing fermentative Escherichia coli and phototrophic Rhodopseudomonas palustris. In this coculture, E. coli and R. palustris resemble an anaerobic food web by cross-feeding essential carbon (organic acids) and nitrogen (ammonium) respectively. Organic acid cross-feeding stemming from E. coli fermentation can continue in a growth-independent manner during nitrogen limitation, while ammonium cross-feeding by R. palustris is growth-dependent. When ammonium cross-feeding was limited, coculture trends changed yet coexistence persisted under both homogenous and heterogenous conditions. Theoretical modelling indicated that growth-independent fermentation was crucial to sustain cooperative growth under conditions of low nutrient exchange. In contrast to stabilization at most cell densities, growth-independent fermentation inhibited mutualistic growth when the E. coli cell density was adequately high relative to that of R. palustris. Thus, growth-independent fermentation can conditionally stabilize or destabilize a mutualism, indicating the potential importance of growth-independent metabolism for nutrient-limited mutualistic communities.
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Affiliation(s)
| | - Breah LaSarre
- Department of Biology, Indiana University, Bloomington, IN, USA
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52
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Joshi VS, Kreth J, Koley D. Pt-Decorated MWCNTs-Ionic Liquid Composite-Based Hydrogen Peroxide Sensor To Study Microbial Metabolism Using Scanning Electrochemical Microscopy. Anal Chem 2017; 89:7709-7718. [PMID: 28613833 PMCID: PMC6261441 DOI: 10.1021/acs.analchem.7b01677] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hydrogen peroxide (H2O2) is a highly relevant metabolite in many biological processes, including the oral microbiome. To study this metabolite, we developed a 25 μm diameter, highly sensitive, nonenzymatic H2O2 sensor with a detection limit of 250 nM and a broad linear range of 250 nM to 7 mM. The sensor used the synergistic activity of the catalytically active Pt nanoparticles on a high surface area multiwalled carbon nanotube and conducting ionic liquid matrix to achieve high sensitivity (2.4 ± 0.24 mA cm-2 mM-1) for H2O2 oxidation. The unique composite allowed us to miniaturize the sensor and couple it with a Pt electrode (25 μm diameter each) for use as a dual scanning electrochemical microscopy probe. We could detect 65 ± 10 μM H2O2 produced by Streptococcus gordonii (Sg) in a simulated biofilm at 50 μm above its surface in the presence of 1 mM glucose and artificial saliva solution (pH 7.2 at 37 °C). Because of its high stability and low detection limit, the sensor showed a promising chemical image of H2O2 produced by Sg biofilms. We were also able to detect 30 μM H2O2 at 50 μm above the biofilm in the presence of the H2O2-decomposing salivary lactoperoxidase and thiocyanate, which would not otherwise be possible using an existing H2O2 assay. Thus, this sensor can potentially find applications in the study of other important biological processes in a complex matrix where circumstances demand a low detection limit in a compact space.
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Affiliation(s)
- Vrushali S Joshi
- Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA
| | - Jens Kreth
- Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR USA
| | - Dipankar Koley
- Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA
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53
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Hernandez-Sanabria E, Slomka V, Herrero ER, Kerckhof FM, Zaidel L, Teughels W, Boon N. In vitro Increased Respiratory Activity of Selected Oral Bacteria May Explain Competitive and Collaborative Interactions in the Oral Microbiome. Front Cell Infect Microbiol 2017. [PMID: 28638806 PMCID: PMC5461333 DOI: 10.3389/fcimb.2017.00235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Understanding the driving forces behind the shifts in the ecological balance of the oral microbiota will become essential for the future management and treatment of periodontitis. As the use of competitive approaches for modulating bacterial outgrowth is unexplored in the oral ecosystem, our study aimed to investigate both the associations among groups of functional compounds and the impact of individual substrates on selected members of the oral microbiome. We employed the Phenotype Microarray high-throughput technology to analyse the microbial cellular phenotypes of 15 oral bacteria. Multivariate statistical analysis was used to detect respiratory activity triggers and to assess similar metabolic activities. Carbon and nitrogen were relevant for the respiration of health-associated bacteria, explaining competitive interactions when grown in biofilms. Carbon, nitrogen, and peptides tended to decrease the respiratory activity of all pathobionts, but not significantly. None of the evaluated compounds significantly increased activity of pathobionts at both 24 and 48 h. Additionally, metabolite requirements of pathobionts were dissimilar, suggesting that collective modulation of their respiratory activity may be challenging. Flow cytometry indicated that the metabolic activity detected in the Biolog plates may not be a direct result of the number of bacterial cells. In addition, damage to the cell membrane may not influence overall respiratory activity. Our methodology confirmed previously reported competitive and collaborative interactions among bacterial groups, which could be used either as marker of health status or as targets for modulation of the oral environment.
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Affiliation(s)
| | - Vera Slomka
- Department of Oral Health SciencesKU Leuven, Leuven, Belgium
| | | | | | - Lynette Zaidel
- Colgate-Palmolive Technology CenterPiscataway, NJ, United States
| | - Wim Teughels
- Department of Oral Health SciencesKU Leuven, Leuven, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology, Ghent UniversityGhent, Belgium
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54
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Kreth J, Giacaman RA, Raghavan R, Merritt J. The road less traveled - defining molecular commensalism with Streptococcus sanguinis. Mol Oral Microbiol 2017; 32:181-196. [PMID: 27476770 PMCID: PMC5288394 DOI: 10.1111/omi.12170] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2016] [Indexed: 12/15/2022]
Abstract
The commensal oral microbial flora has evolved with the human host to support colonization of the various intraoral sites without triggering a significant immune response. In exchange, the commensal microbes provide critical protection against invading pathogens. The intrinsic ability of the oral flora to create a symbiotic microbial community with the host can be disturbed, selecting for the overgrowth of a dysbiotic community that can result in dental diseases, such as caries and periodontitis. Although the mechanisms of molecular pathogenesis in oral diseases are well characterized, much less is known about the molecular mechanisms used by the commensal flora to maintain oral health. Here we focus on the commensal species Streptococcus sanguinis, which is found in abundance in the early oral biofilm and is strongly correlated with oral health. Streptococcus sanguinis exhibits a variety of features that make it ideally suited as a model organism to explore the molecular basis for commensalism. As such, this review will describe our current mechanistic understanding of S. sanguinis commensalism and speculate upon its molecular traits that may be exploitable to maintain or restore oral health under conditions that would otherwise lead to disease.
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Affiliation(s)
- Jens Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - Rodrigo A. Giacaman
- Cariology Unit, Department of Oral Rehabilitation and Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), University of Talca, Talca, Chile
| | - Rahul Raghavan
- Department of Biology and Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
| | - Justin Merritt
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
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55
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Szafrański SP, Deng ZL, Tomasch J, Jarek M, Bhuju S, Rohde M, Sztajer H, Wagner-Döbler I. Quorum sensing of Streptococcus mutans is activated by Aggregatibacter actinomycetemcomitans and by the periodontal microbiome. BMC Genomics 2017; 18:238. [PMID: 28320314 PMCID: PMC5359896 DOI: 10.1186/s12864-017-3618-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/10/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The oral cavity is inhabited by complex microbial communities forming biofilms that can cause caries and periodontitis. Cell-cell communication might play an important role in modulating the physiologies of individual species, but evidence so far is limited. RESULTS Here we demonstrate that a pathogen of the oral cavity, Aggregatibacter actinomycetemcomitans (A. act.), triggers expression of the quorum sensing (QS) regulon of Streptococcus mutans, a well-studied model organism for cariogenic streptococci, in dual-species biofilms grown on artificial saliva. The gene for the synthesis of the QS signal XIP is essential for this interaction. Transcriptome sequencing of biofilms revealed that S. mutans up-regulated the complete QS regulon (transformasome and mutacins) in the presence of A. act. and down-regulated oxidative stress related genes. A.act. required the presence of S. mutans for growth. Fimbriae and toxins were its most highly expressed genes and up-regulation of anaerobic metabolism, chaperones and iron acquisition genes was observed in co-culture. Metatranscriptomes from periodontal pockets showed highly variable levels of S. mutans and low levels of A. act.. Transcripts of the alternative sigma-factor SigX, the key regulator of QS in S. mutans, were significantly enriched in periodontal pockets compared to single cultures (log2 4.159, FDR ≤0.001, and expression of mutacin related genes and transformasome components could be detected. CONCLUSION The data show that the complete QS regulon of S. mutans can be induced by an unrelated oral pathogen and S. mutans may be competent in oral biofilms in vivo.
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Affiliation(s)
- Szymon P Szafrański
- Microbial Communication, Helmholtz-Center for Infection Research, Braunschweig, Germany.,Present address: Hannover Medical School (MHH), Hannover, Germany
| | - Zhi-Luo Deng
- Microbial Communication, Helmholtz-Center for Infection Research, Braunschweig, Germany
| | - Jürgen Tomasch
- Microbial Communication, Helmholtz-Center for Infection Research, Braunschweig, Germany
| | - Michael Jarek
- Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Sabin Bhuju
- Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Helena Sztajer
- Microbial Communication, Helmholtz-Center for Infection Research, Braunschweig, Germany
| | - Irene Wagner-Döbler
- Microbial Communication, Helmholtz-Center for Infection Research, Braunschweig, Germany.
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56
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Kirkpatrick CL, Lesouhaitier O, Malone JG, An SQ, Caly DL. Interaction and signalling networks: a report from the fourth 'Young Microbiologists Symposium on Microbe Signalling, Organisation and Pathogenesis'. MICROBIOLOGY-SGM 2016; 163:4-8. [PMID: 27902434 DOI: 10.1099/mic.0.000401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
At the end of June, over 120 microbiologists from 18 countries gathered in Dundee, Scotland for the fourth edition of the Young Microbiologists Symposium on 'Microbe Signalling, Organisation and Pathogenesis'. The aim of the symposium was to give early career microbiologists the opportunity to present their work in a convivial environment and to interact with senior world-renowned scientists in exciting fields of microbiology research. The meeting was supported by the Microbiology Society, the Society of Applied Microbiology and the American Society for Microbiology with further sponsorship from the European Molecular Biology Organisation and the Royal Society of Edinburgh. In this report, we highlight some themes that emerged from the many interesting talks and poster presentations, as well as some of the other activities that were on offer at this energetic meeting.
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Affiliation(s)
- Clare L Kirkpatrick
- Department of Microbiology & Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), Faculty of Medicine/University Medical Centre, University of Geneva, Geneva, Switzerland
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment, Normandy University, Université de Rouen, Évreux, France
| | - Jacob G Malone
- University of East Anglia, Norwich, UK.,John Innes Centre, Norwich Research Park, Norwich, UK
| | - Shi-Qi An
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Delphine L Caly
- Institut Charles Viollette - ICV, Univ Lille, EA 7394, Lille, France
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57
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Ramsey MM, Freire MO, Gabrilska RA, Rumbaugh KP, Lemon KP. Staphylococcus aureus Shifts toward Commensalism in Response to Corynebacterium Species. Front Microbiol 2016; 7:1230. [PMID: 27582729 PMCID: PMC4988121 DOI: 10.3389/fmicb.2016.01230] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/25/2016] [Indexed: 12/19/2022] Open
Abstract
Staphylococcus aureus-human interactions result in a continuum of outcomes from commensalism to pathogenesis. S. aureus is a clinically important pathogen that asymptomatically colonizes ~25% of humans as a member of the nostril and skin microbiota, where it resides with other bacteria including commensal Corynebacterium species. Commensal Corynebacterium spp. are also positively correlated with S. aureus in chronic polymicrobial diabetic foot infections, distinct from acute monomicrobial S. aureus infections. Recent work by our lab and others indicates that microbe-microbe interactions between S. aureus and human skin/nasal commensals, including Corynebacterium species, affect S. aureus behavior and fitness. Thus, we hypothesized that S. aureus interactions with Corynebacterium spp. diminish S. aureus virulence. We tested this by assaying for changes in S. aureus gene expression during in vitro mono- versus coculture with Corynebacterium striatum, a common skin and nasal commensal. We observed a broad shift in S. aureus gene transcription during in vitro growth with C. striatum, including increased transcription of genes known to exhibit increased expression during human nasal colonization and decreased transcription of virulence genes. S. aureus uses several regulatory pathways to transition between commensal and pathogenic states. One of these, the quorum signal accessory gene regulator (agr) system, was strongly inhibited in response to Corynebacterium spp. Phenotypically, S. aureus exposed to C. striatum exhibited increased adhesion to epithelial cells, reflecting a commensal state, and decreased hemolysin activity, reflecting an attenuation of virulence. Consistent with this, S. aureus displayed diminished fitness in experimental in vivo coinfection with C. striatum when compared to monoinfection. These data support a model in which S. aureus shifts from virulence toward a commensal state when exposed to commensal Corynebacterium species.
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Affiliation(s)
- Matthew M. Ramsey
- Department of Microbiology, The Forsyth Institute, Cambridge, MAUSA
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MAUSA
| | - Marcelo O. Freire
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MAUSA
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, MAUSA
| | - Rebecca A. Gabrilska
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TXUSA
| | - Kendra P. Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TXUSA
| | - Katherine P. Lemon
- Department of Microbiology, The Forsyth Institute, Cambridge, MAUSA
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MAUSA
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58
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Abstract
Infections caused by multiple organisms, or polymicrobial infections, are likely more common than is broadly appreciated. Interaction among microbial communities (and with their host) can change the infection landscape by subverting immunity, providing nutrients and inhibiting competing microbes. Stacy et al. (A. Stacy, D. Fleming, R. J. Lamont, K. P. Rumbaugh, and M. Whiteley, mBio 7:e00782-16, 2016, http://dx.doi.org/10.1128/mBio.00782-16) described a novel mechanism that results in synergistic growth of oral microbes Aggregatibacter actinomycetemcomitans and Streptococcus gordonii. The authors used whole-genome fitness profiling by transposon sequencing (Tn-seq) to identify genes differentially required for growth in vitro versus in a mono- or coinfection in a thigh abscess model. They found that coinfection with S. gordonii allowed A. actinomycetemcomitans to shift from an anaerobic to an aerobic mode of growth. This shift involved the production of a terminal electron acceptor H2O2 by S. gordonii and increased A. actinomycetemcomitans persistence—an interaction termed “cross-respiration.”
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59
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Duan D, Scoffield JA, Zhou X, Wu H. Fine-tuned production of hydrogen peroxide promotes biofilm formation of Streptococcus parasanguinis by a pathogenic cohabitant Aggregatibacter actinomycetemcomitans. Environ Microbiol 2016; 18:4023-4036. [PMID: 27348605 DOI: 10.1111/1462-2920.13425] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 06/13/2016] [Accepted: 06/19/2016] [Indexed: 11/28/2022]
Abstract
Balanced bacterial biofilm communities help to maintain host health. Disturbance of such balance can lead to bacterial dysbiosis and pathogenesis. However, complex and dynamic bacterial interactions within the biofilm communities are poorly understood. In this study, we used a dual-species biofilm consisting of the periodontal pathogen Aggregatibacter actinomycetemcomitans, and a commensal Streptococcus parasanguinis to investigate bacterial interactions since the two organisms have been found to coexist during the development of localized aggressive periodontal disease. We report that A. actinomycetemcomitans promoted biofilm formation of S. parasanguinis in vitro and in vivo. Protein profiling of S. parasanguinis co-cultured with A. actinomycetemcomitans revealed a significant decrease in the protein level of pyruvate oxidase(PoxL), an enzyme required for the generation of hydrogen peroxide (H2 O2 ). Consistently, the H2 O2 concentration was concurrently decreased. However, the complete removal of H2 O2 impaired the biofilm formation. H2 O2 at a low concentration range regulated by A. actinomycetemcomitans enhanced the biofilm formation. These results demonstrate that A. actinomycetemcomitans promotes the S. parasanguinis biofilm formation through modulating the production of H2 O2 by fine-tuning the expression of poxL, indicating that H2 O2 functions as a signaling molecule. Taken together, this report revealed a previously unknown bacteria-bacteria interaction mechanism.
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Affiliation(s)
- Dingyu Duan
- Departments of Pediatric Dentistry and Microbiology, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.,State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, 610041, China
| | - Jessica A Scoffield
- Departments of Pediatric Dentistry and Microbiology, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, 610041, China
| | - Hui Wu
- Departments of Pediatric Dentistry and Microbiology, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
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60
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Abreu NA, Taga ME. Decoding molecular interactions in microbial communities. FEMS Microbiol Rev 2016; 40:648-63. [PMID: 27417261 DOI: 10.1093/femsre/fuw019] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2016] [Indexed: 12/21/2022] Open
Abstract
Microbial communities govern numerous fundamental processes on earth. Discovering and tracking molecular interactions among microbes is critical for understanding how single species and complex communities impact their associated host or natural environment. While recent technological developments in DNA sequencing and functional imaging have led to new and deeper levels of understanding, we are limited now by our inability to predict and interpret the intricate relationships and interspecies dependencies within these communities. In this review, we highlight the multifaceted approaches investigators have taken within their areas of research to decode interspecies molecular interactions that occur between microbes. Understanding these principles can give us greater insight into ecological interactions in natural environments and within synthetic consortia.
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Affiliation(s)
- Nicole A Abreu
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA
| | - Michiko E Taga
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA
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61
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M Harriott M. In Vitro Antifungal-Antibacterial Combinations are Effective Against MRSA in Candida albicans-Staphylococcus aureus Polymicrobial Biofilms. ACTA ACUST UNITED AC 2016. [DOI: 10.15406/jmen.2016.03.00090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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62
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Keiser CN, Shearer TA, DeMarco AE, Brittingham HA, Knutson KA, Kuo C, Zhao K, Pruitt JN. Cuticular bacteria appear detrimental to social spiders in mixed but not monoculture exposure. Curr Zool 2016; 62:377-384. [PMID: 29491926 PMCID: PMC5829440 DOI: 10.1093/cz/zow015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/22/2015] [Indexed: 12/15/2022] Open
Abstract
Much of an animal’s health status, life history, and behavior are dictated by
interactions with its endogenous and exogenous bacterial communities. Unfortunately,
interactions between hosts and members of their resident bacterial community are often
ignored in animal behavior and behavioral ecology. Here, we aim to identify the nature of
host–microbe interactions in a nonmodel organism, the African social spider
Stegodyphus dumicola. We collected and identified bacteria from the
cuticles of spiders in situ and then exposed spiders to bacterial
monocultures cultures via topical application or injection. We also topically inoculated
spiders with a concomitant “cocktail” of bacteria and measured the behavior of spiders
daily for 24 days after inoculation. Lastly, we collected and identified bacteria from the
cuticles of prey items in the capture webs of spiders, and then fed spiders domestic
crickets which had been injected with these bacteria. We also injected 1 species of
prey-borne bacteria into the hemolymph of spiders. Only Bacillus
thuringiensis caused increased mortality when injected into the hemolymph of
spiders, whereas no bacterial monocultures caused increased mortality when applied
topically, relative to control solutions. However, a bacterial cocktail of cuticular
bacteria caused weight loss and mortality when applied topically, yet did not detectibly
alter spider behavior. Consuming prey injected with prey-borne bacteria was associated
with an elongated lifespan in spiders. Thus, indirect evidence from multiple experiments
suggests that the effects of these bacteria on spider survivorship appear contingent on
their mode of colonization and whether they are applied in monoculture or within a mixed
cocktail. We urge that follow-up studies should test these host–microbe interactions
across different social contexts to determine the role that microbes play in colony
performance.
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Affiliation(s)
- Carl N Keiser
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Taylor A Shearer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Alexander E DeMarco
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Hayley A Brittingham
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Karen A Knutson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Candice Kuo
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Katherine Zhao
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Jonathan N Pruitt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 USA
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64
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Scoffield JA, Wu H. Nitrite reductase is critical for Pseudomonas aeruginosa survival during co-infection with the oral commensal Streptococcus parasanguinis. MICROBIOLOGY-SGM 2015; 162:376-383. [PMID: 26673783 DOI: 10.1099/mic.0.000226] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Pseudomonas aeruginosa is the major aetiological agent of chronic pulmonary infections in cystic fibrosis (CF) patients. However, recent evidence suggests that the polymicrobial community of the CF lung may also harbour oral streptococci, and colonization by these micro-organisms may have a negative impact on P. aeruginosa within the CF lung. Our previous studies demonstrated that nitrite abundance plays an important role in P. aeruginosa survival during co-infection with oral streptococci. Nitrite reductase is a key enzyme involved in nitrite metabolism. Therefore, the objective of this study was to examine the role nitrite reductase (gene nirS) plays in P. aeruginosa survival during co-infection with an oral streptococcus, Streptococcus parasanguinis. Inactivation of nirS in both the chronic CF isolate FRD1 and acute wound isolate PAO1 reduced the survival rate of P. aeruginosa when co-cultured with S. parasanguinis. Growth of both mutants was restored when co-cultured with S. parasanguinis that was defective for H2O2 production. Furthermore, the nitrite reductase mutant was unable to kill Drosophila melanogaster during co-infection with S. parasanguinis. Taken together, these results suggest that nitrite reductase plays an important role for survival of P. aeruginosa during co-infection with S. parasanguinis.
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Affiliation(s)
- Jessica A Scoffield
- Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hui Wu
- Department of Pediatric Dentistry, School of Dentistry, University of Alabama at Birmingham, Birmingham, AL, USA
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65
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Roberts FA, Darveau RP. Microbial protection and virulence in periodontal tissue as a function of polymicrobial communities: symbiosis and dysbiosis. Periodontol 2000 2015; 69:18-27. [PMID: 26252399 PMCID: PMC4530467 DOI: 10.1111/prd.12087] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2014] [Indexed: 12/13/2022]
Abstract
This review discusses polymicrobial interactions with the host in both health and disease. As our ability to identify specific bacterial clonal types, with respect to their abundance and location in the oral biofilm, improves, we will learn more concerning their contribution to both oral health and disease. Recent studies examining host- bacteria interactions have revealed that commensal bacteria not only protect the host simply by niche occupation, but that bacterial interactions with host tissue can promote the development of proper tissue structure and function. These data indicate that our host-associated polymicrobial communities, such as those found in the oral cavity, co-evolved with us and have become an integral part of who we are. Understanding the microbial community factors that underpin the associations with host tissue that contribute to periodontal health may also reveal how dysbiotic periodontopathic oral communities disrupt normal periodontal tissue functions in disease. A disruption of the oral microbial community creates dysbiosis, either by overgrowth of specific or nonspecific microorganisms or by changes in the local host response where the community can now support a disease state. Dysbiosis provides the link between systemic changes (e.g. diabetes) and exogenous risk factors (e.g. smoking), and the dysbiotic community, and can drive the destruction of periodontal tissue. Many other risk factors associated with periodontal disease, such as stress, aging and genetics, are also likely to affect the microbial community, and more research is needed, utilizing sophisticated bacterial taxonomic techniques, to elucidate these effects on the microbiome and to develop strategies to target the dysbiotic mechanisms and improve periodontal health.
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Affiliation(s)
- Frank A. Roberts
- University of Washington, School of Dentistry, Department of Periodontics, 1959 NE Pacific Street, Box 357444, Seattle Washington 98195-7444, Phone: 206-685-9046, Fax: 206-616-7478
| | - Richard P. Darveau
- University of Washington, School of Dentistry, Department of Periodontics, 1959 NE Pacific Street, Box 357444, Seattle Washington 98195-7444, Phone: 206-543-9514, Fax: 206-616-7478
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66
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Abstract
This paper considers whether multispecies biofilms are evolutionary individuals. Numerous multispecies biofilms have characteristics associated with individuality, such as internal integrity, division of labor, coordination among parts, and heritable adaptive traits. However, such multispecies biofilms often fail standard reproductive criteria for individuality: they lack reproductive bottlenecks, are comprised of multiple species, do not form unified reproductive lineages, and fail to have a significant division of reproductive labor among their parts. If such biofilms are good candidates for evolutionary individuals, then evolutionary individuality is achieved through other means than frequently cited reproductive processes. The case of multispecies biofilms suggests that standard reproductive requirements placed on individuality should be reconsidered. More generally, the case of multispecies biofilms indicates that accounts of individuality that focus on single-species eukaryotes are too restrictive and that a pluralistic and open-ended account of evolutionary individuality is needed.
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Affiliation(s)
- Marc Ereshefsky
- Department of Philosophy, University of Calgary, Calgary, AB, Canada T2N 1N4;
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Xu H, Jenkinson HF, Dongari-Bagtzoglou A. Innocent until proven guilty: mechanisms and roles of Streptococcus-Candida interactions in oral health and disease. Mol Oral Microbiol 2015; 29:99-116. [PMID: 24877244 PMCID: PMC4238848 DOI: 10.1111/omi.12049] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Candida albicans and streptococci of the mitis group colonize the oral cavities of the majority of healthy humans. While C. albicans is considered an opportunistic pathogen, streptococci of this group are broadly considered avirulent or even beneficial organisms. However, recent evidence suggests that multi-species biofilms with these organisms may play detrimental roles in host homeostasis and may promote infection. In this review we summarize the literature on molecular interactions between members of this streptococcal group and C. albicans, with emphasis on their potential role in the pathogenesis of opportunistic oral mucosal infections.
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Dharmaprakash A, Thandavarayan R, Joseph I, Thomas S. Development of broad-spectrum antibiofilm drugs: strategies and challenges. Future Microbiol 2015; 10:1035-48. [DOI: 10.2217/fmb.15.14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
ABSTRACT The severity of many chronic bacterial infections is mainly due to the biofilm mode of life adapted by pathogenic bacteria. The bacteria in biofilm-stage exhibit high resistance to host immune responses and antimicrobials, which complicates the treatment process and results in life threatening conditions. Most of the chronic infections are polymicrobial in nature. In order to combat the polymicrobial biofilm infections and to increase the efficiency of antimicrobials, there is an urgent need for broad-spectrum antibiofilm drugs. This review discusses the clinical needs and current status of broad-spectrum antibiofilm drugs with special emphasis on prospective strategies and hurdles in the process of new drug discovery.
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Affiliation(s)
- Akhilandeswarre Dharmaprakash
- Cholera & Biofilm Research Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram – 695 014, Kerala, India
| | | | - Iype Joseph
- Pathogen Biology Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram – 695 014, Kerala, India
| | - Sabu Thomas
- Cholera & Biofilm Research Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram – 695 014, Kerala, India
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Karched M, Bhardwaj RG, Asikainen SE. Coaggregation and biofilm growth of Granulicatella spp. with Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans. BMC Microbiol 2015; 15:114. [PMID: 26025449 PMCID: PMC4448563 DOI: 10.1186/s12866-015-0439-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/08/2015] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Members of fastidious Granulicatella and Aggregatibacter genera belong to normal oral flora bacteria that can cause serious infections, such as infective endocarditis. Aggregatibacter actinomycetemcomitans has long been implicated in aggressive periodontitis, whereas DNA-based methods only recently showed an association between Granulicatella spp. and dental diseases. As bacterial coaggregation is a key phenomenon in the development of oral and nonoral multispecies bacterial communities it would be of interest knowing coaggregation pattern of Granulicatella species with A. actinomycetemcomitans in comparison with the multipotent coaggregator Fusobacterium nucleatum. The aim was to investigate coaggregation and biofilm formation of Granulicatella elegans and Granulicatella adiacens with A. actinomycetemcomitans and F. nucleatum strains. RESULTS F. nucleatum exhibited significantly (p < 0.05) higher autoaggregation than all other test species, followed by A. actinomycetemcomitans SA269 and G. elegans. A. actinomycetemcomitans CU1060 and G. adiacens did not autoaggregate. G. elegans with F. nucleatum exhibited significantly (p < 0.05) higher coaggregation than most others, but failed to grow as biofilm together or separately. With F. nucleatum as partner, A. actinomycetemcomitans strains SA269, a rough-colony wild-type strain, and CU1060, a spontaneous smooth-colony laboratory variant, and G. adiacens were the next in coaggregation efficiency. These dual species combinations also were able to grow as biofilms. While both G. elegans and G. adiacens coaggregated with A. actinomycetemcomitans strain SA269, but not with CU1060, they grew as biofilms with both A. actinomycetemcomitans strains. CONCLUSIONS G. elegans failed to form biofilm with F. nucleatum despite the strongest coaggregation with it. The ability of Granulicatella spp. to coaggregate and/or form biofilms with F. nucleatum and A. actinomycetemcomitans strains suggests that Granulicatella spp. have the potential to integrate into dental plaque biofilms.
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Affiliation(s)
- Maribasappa Karched
- General Facility Oral Microbiology Laboratory, Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Kuwait, Kuwait.
| | - Radhika G Bhardwaj
- General Facility Oral Microbiology Laboratory, Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Kuwait, Kuwait.
| | - Sirkka E Asikainen
- General Facility Oral Microbiology Laboratory, Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Kuwait, Kuwait.
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Parashar A, Parashar S, Zingade A, Gupta S, Sanikop S. Interspecies communication in oral biofilm: An ocean of information. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/s1348-8643(15)00016-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Shanmugam M, Gopal P, El Abbar F, Schreiner HC, Kaplan JB, Fine DH, Ramasubbu N. Role of exopolysaccharide in Aggregatibacter actinomycetemcomitans-induced bone resorption in a rat model for periodontal disease. PLoS One 2015; 10:e0117487. [PMID: 25706999 PMCID: PMC4338281 DOI: 10.1371/journal.pone.0117487] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 12/24/2014] [Indexed: 11/19/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans a causative agent of periodontal disease in humans, forms biofilm on biotic and abiotic surfaces. A. actinomycetemcomitans biofilm is heterogeneous in nature and is composed of proteins, extracellular DNA and exopolysaccharide. To explore the role played by the exopolysaccharide in the colonization and disease progression, we employed genetic reduction approach using our rat model of A. actinomycetemcomitans-induced periodontitis. To this end, a genetically modified strain of A. actinomycetemcomitans lacking the pga operon was compared with the wild-type strain in the rat infection model. The parent and mutant strains were primarily evaluated for bone resorption and disease. Our study showed that colonization, bone resorption/disease and antibody response were all elevated in the wild-type fed rats. The bone resorption/disease caused by the pga mutant strain, lacking the exopolysaccharide, was significantly less (P < 0.05) than the bone resorption/disease caused by the wild-type strain. Further analysis of the expression levels of selected virulence genes through RT-PCR showed that the decrease in colonization, bone resorption and antibody titer in the absence of the exopolysaccharide might be due to attenuated levels of colonization genes, flp-1, apiA and aae in the mutant strain. This study demonstrates that the effect exerted by the exopolysaccharide in A. actinomycetemcomitans-induced bone resorption has hitherto not been recognized and underscores the role played by the exopolysaccharide in A. actinomycetemcomitans-induced disease.
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Affiliation(s)
- Mayilvahanan Shanmugam
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America
| | - Prerna Gopal
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America
| | - Faiha El Abbar
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America
| | - Helen C Schreiner
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America
| | - Jeffrey B Kaplan
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America
| | - Daniel H Fine
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America
| | - Narayanan Ramasubbu
- Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ, 07103, United States of America
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72
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Estrela S, Whiteley M, Brown SP. The demographic determinants of human microbiome health. Trends Microbiol 2014; 23:134-41. [PMID: 25500524 DOI: 10.1016/j.tim.2014.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/06/2014] [Accepted: 11/12/2014] [Indexed: 12/22/2022]
Abstract
The human microbiome is a vast reservoir of microbial diversity and increasingly recognized to have a fundamental role in human health. In polymicrobial communities, the presence of one species can modulate the demography (i.e., growth and distribution) of other species. These demographic impacts generate feedbacks in multispecies interactions, which can be magnified in spatially structured populations (e.g., host-associated communities). Here, we argue that demographic feedbacks between species are central to microbiome development, shaping whether and how potential metabolic interactions come to be realized between expanding lineages of bacteria. Understanding how demographic feedbacks tune metabolic interactions and in turn shape microbiome structure and function is now a key challenge to our abilities to better manage microbiome health.
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Affiliation(s)
- Sylvie Estrela
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK; Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, EH9 3JT, UK; Department of Biology and BEACON Center for the Study of Evolution in Action, University of Washington, Seattle, WA 98195, USA.
| | - Marvin Whiteley
- Department of Molecular Biosciences, Institute of Cellular and Molecular Biology, Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sam P Brown
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK; Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, EH9 3JT, UK.
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McLean RJC. Normal bacterial flora may inhibit Candida albicans biofilm formation by Autoinducer-2. Front Cell Infect Microbiol 2014; 4:117. [PMID: 25221750 PMCID: PMC4147847 DOI: 10.3389/fcimb.2014.00117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/11/2014] [Indexed: 01/28/2023] Open
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Vega LM, Alvarez PJ, McLean RJC. Bacterial signaling ecology and potential applications during aquatic biofilm construction. MICROBIAL ECOLOGY 2014; 68:24-34. [PMID: 24276538 DOI: 10.1007/s00248-013-0321-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 10/24/2013] [Indexed: 06/02/2023]
Abstract
In their natural environment, bacteria and other microorganisms typically grow as surface-adherent biofilm communities. Cell signal processes, including quorum signaling, are now recognized as being intimately involved in the development and function of biofilms. In contrast to their planktonic (unattached) counterparts, bacteria within biofilms are notoriously resistant to many traditional antimicrobial agents and so represent a major challenge in industry and medicine. Although biofilms impact many human activities, they actually represent an ancient mode of bacterial growth as shown in the fossil record. Consequently, many aquatic organisms have evolved strategies involving signal manipulation to control or co-exist with biofilms. Here, we review the chemical ecology of biofilms and propose mechanisms whereby signal manipulation can be used to promote or control biofilms.
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Affiliation(s)
- Leticia M Vega
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, 77005, USA
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75
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Guo L, He X, Shi W. Intercellular communications in multispecies oral microbial communities. Front Microbiol 2014; 5:328. [PMID: 25071741 PMCID: PMC4076886 DOI: 10.3389/fmicb.2014.00328] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 06/14/2014] [Indexed: 01/22/2023] Open
Abstract
The oral cavity contains more than 700 microbial species that are engaged in extensive cell–cell interactions. These interactions contribute to the formation of highly structured multispecies communities, allow them to perform physiological functions, and induce synergistic pathogenesis. Co-adhesion between oral microbial species influences their colonization of oral cavity and effectuates, to a large extent, the temporal and spatial formation of highly organized polymicrobial community architecture. Individual species also compete and collaborate with other neighboring species through metabolic interactions, which not only modify the local microenvironment such as pH and the amount of oxygen, making it more suitable for the growth of other species, but also provide a metabolic framework for the participating microorganisms by maximizing their potential to extract energy from limited substrates. Direct physical contact of bacterial species with its neighboring co-habitants within microbial community could initiate signaling cascade and achieve modulation of gene expression in accordance with different species it is in contact with. In addition to communication through cell–cell contact, quorum sensing (QS) mediated by small signaling molecules such as competence-stimulating peptides (CSPs) and autoinducer-2 (AI-2), plays essential roles in bacterial physiology and ecology. This review will summarize the evidence that oral microbes participate in intercellular communications with co-inhabitants through cell contact-dependent physical interactions, metabolic interdependencies, as well as coordinative signaling systems to establish and maintain balanced microbial communities.
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Affiliation(s)
- Lihong Guo
- School of Dentistry, University of California-Los Angeles, Los Angeles CA, USA
| | - Xuesong He
- School of Dentistry, University of California-Los Angeles, Los Angeles CA, USA
| | - Wenyuan Shi
- School of Dentistry, University of California-Los Angeles, Los Angeles CA, USA
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Short FL, Murdoch SL, Ryan RP. Polybacterial human disease: the ills of social networking. Trends Microbiol 2014; 22:508-16. [PMID: 24938173 PMCID: PMC4158425 DOI: 10.1016/j.tim.2014.05.007] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 05/17/2014] [Accepted: 05/22/2014] [Indexed: 02/06/2023]
Abstract
Bacteria are typically found within complex microbial communities in nature. Molecular interactions between co-infecting bacteria can profoundly affect disease prognosis and treatment. In vivo models and genomic tools are providing new insights into interbacterial behavior during infection. There is potential to target interbacterial interactions as part of a therapeutic strategy.
Polybacterial diseases involve multiple organisms that act collectively to facilitate disease progression. Although this phenomenon was highlighted early in the 20th century, recent technological advances in diagnostics have led to the appreciation that many infections are far more complex than originally believed. Furthermore, it is apparent that although most treatments focus on the dominant bacterial species in an infection, other microbes, including commensals, can have a profound impact on both the response to therapy and virulence. Very little is known about the molecular mechanisms that underpin interactions between bacteria during such infections. Here, we discuss recent studies identifying and characterizing mechanisms of bacterial interaction and the biological processes they govern during certain diseases. We also highlight how possible strategies for targeting these interbacterial interactions may afford a route towards development of new therapies, with consequences for disease control.
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Affiliation(s)
- Francesca L Short
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, UK
| | - Sarah L Murdoch
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, UK
| | - Robert P Ryan
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee, UK.
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Bacterial fight-and-flight responses enhance virulence in a polymicrobial infection. Proc Natl Acad Sci U S A 2014; 111:7819-24. [PMID: 24825893 DOI: 10.1073/pnas.1400586111] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The oral pathogen Aggregatibacter actinomycetemcomitans (Aa) resides in infection sites with many microbes, including commensal streptococci such as Streptococcus gordonii (Sg). During infection, Sg promotes the virulence of Aa by producing its preferred carbon source, l-lactate, a phenomenon referred to as cross-feeding. However, as with many streptococci, Sg also produces high levels of the antimicrobial hydrogen peroxide (H2O2), leading to the question of how Aa deals with this potent antimicrobial during coinfection. Here, we show that Aa possesses two complementary responses to H2O2: a detoxification or fight response mediated by catalase (KatA) and a dispersion or flight response mediated by Dispersin B (DspB), an enzyme that dissolves Aa biofilms. Using a murine abscess infection model, we show that both of these responses are required for Sg to promote Aa virulence. Although the role of KatA is to detoxify H2O2 during coinfection, 3D spatial analysis of mixed infections revealed that DspB is required for Aa to spatially organize itself at an optimal distance (>4 µm) from Sg, which we propose allows cross-feeding but reduces exposure to inhibitory levels of H2O2. In addition, these behaviors benefit not only Aa but also Sg, suggesting that fight and flight stimulate the fitness of the community. These results reveal that an antimicrobial produced by a human commensal bacterium enhances the virulence of a pathogenic bacterium by modulating its spatial location in the infection site.
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78
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Wright CJ, Xue P, Hirano T, Liu C, Whitmore SE, Hackett M, Lamont RJ. Characterization of a bacterial tyrosine kinase in Porphyromonas gingivalis involved in polymicrobial synergy. Microbiologyopen 2014; 3:383-94. [PMID: 24811194 PMCID: PMC4082711 DOI: 10.1002/mbo3.177] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/18/2014] [Accepted: 03/25/2014] [Indexed: 12/30/2022] Open
Abstract
Interspecies communication between Porphyromonas gingivalis and Streptococcus gordonii underlies the development of synergistic dual species communities. Contact with S. gordonii initiates signal transduction within P. gingivalis that is based on protein tyrosine (de)phosphorylation. In this study, we characterize a bacterial tyrosine (BY) kinase (designated Ptk1) of P. gingivalis and demonstrate its involvement in interspecies signaling. Ptk1 can utilize ATP for autophosphorylation and is dephosphorylated by the P. gingivalis tyrosine phosphatase, Ltp1. Community development with S. gordonii is severely abrogated in a ptk1 mutant of P. gingivalis, indicating that tyrosine kinase activity is required for maximal polymicrobial synergy. Ptk1 controls the levels of the transcriptional regulator CdhR and the fimbrial adhesin Mfa1 which mediates binding to S. gordonii. The ptk1 gene is in an operon with two genes involved in exopolysaccharide synthesis, and similar to other BY kinases, Ptk1 is necessary for exopolysaccharide production in P. gingivalis. Ptk1 can phosphorylate the capsule related proteins PGN_0224, a UDP-acetyl-mannosamine dehydrogenase, and PGN_0613, a UDP-glucose dehydrogenase, in P. gingivalis. Knockout of ptk1 in an encapsulated strain of P. gingivalis resulted in loss of capsule production. Collectively these results demonstrate that the P. gingivalis Ptk1 BY kinase regulates interspecies communication and controls heterotypic community development with S. gordonii through adjusting the levels of the Mfa1 adhesin and exopolysaccharide.
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Affiliation(s)
- Christopher J Wright
- Oral Health and Systemic Disease, University of Louisville, Louisville, Kentucky, 40202
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Jiao Y, Hasegawa M, Inohara N. The Role of Oral Pathobionts in Dysbiosis during Periodontitis Development. J Dent Res 2014; 93:539-46. [PMID: 24646638 DOI: 10.1177/0022034514528212] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/21/2014] [Indexed: 12/29/2022] Open
Abstract
An emerging concept is the tight relationship between dysbiosis (microbiota imbalance) and disease. The increase in knowledge about alterations in microbial communities that reside within the host has made a strong impact not only on dental science, but also on immunology and microbiology as well as on our understanding of several diseases. Periodontitis is a well-characterized human disease associated with dysbiosis, characterized by the accumulation of multiple bacteria that play individual and critical roles in bone loss around the teeth. Dysbiosis is largely dependent on cooperative and competitive interactions among oral microbes during the formation of the pathogenic biofilm community at gingival sites. Oral pathobionts play different and synergistic roles in periodontitis development, depending on their host-damaging and immunostimulatory activities. Host immune responses to oral pathobionts act as a double-edged sword not only by protecting the host against pathobionts, but also by promoting alveolar bone loss. Recent studies have begun to elucidate the roles of individual oral bacteria, including a new type of pathobionts that possess strong immunostimulatory activity, which is critical for alveolar bone loss. Better understanding of the roles of oral pathobionts is expected to lead to a better understanding of periodontitis disease and to the development of novel preventive and therapeutic approaches for the disease.
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Affiliation(s)
- Y Jiao
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - M Hasegawa
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - N Inohara
- Department of Pathology, The University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Murray JL, Connell JL, Stacy A, Turner KH, Whiteley M. Mechanisms of synergy in polymicrobial infections. J Microbiol 2014; 52:188-99. [PMID: 24585050 PMCID: PMC7090983 DOI: 10.1007/s12275-014-4067-3] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 02/06/2014] [Indexed: 01/09/2023]
Abstract
Communities of microbes can live almost anywhere and contain many different species. Interactions between members of these communities often determine the state of the habitat in which they live. When these habitats include sites on the human body, these interactions can affect health and disease. Polymicrobial synergy can occur during infection, in which the combined effect of two or more microbes on disease is worse than seen with any of the individuals alone. Powerful genomic methods are increasingly used to study microbial communities, including metagenomics to reveal the members and genetic content of a community and metatranscriptomics to describe the activities of community members. Recent efforts focused toward a mechanistic understanding of these interactions have led to a better appreciation of the precise bases of polymicrobial synergy in communities containing bacteria, eukaryotic microbes, and/or viruses. These studies have benefited from advances in the development of in vivo models of polymicrobial infection and modern techniques to profile the spatial and chemical bases of intermicrobial communication. This review describes the breadth of mechanisms microbes use to interact in ways that impact pathogenesis and techniques to study polymicrobial communities.
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Affiliation(s)
- Justine L. Murray
- Department of Molecular Biosciences, Institute of Cell and Molecular Biology, Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712 USA
| | - Jodi L. Connell
- Department of Molecular Biosciences, Institute of Cell and Molecular Biology, Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712 USA
| | - Apollo Stacy
- Department of Molecular Biosciences, Institute of Cell and Molecular Biology, Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712 USA
| | - Keith H. Turner
- Department of Molecular Biosciences, Institute of Cell and Molecular Biology, Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712 USA
| | - Marvin Whiteley
- Department of Molecular Biosciences, Institute of Cell and Molecular Biology, Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712 USA
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Exterkate R, Zaura E, Buijs M, Koopman J, Crielaard W, ten Cate J. The Effects of Propidium Monoazide Treatment on the Measured Composition of Polymicrobial Biofilms after Treatment with Chlorhexidine. Caries Res 2014; 48:291-8. [DOI: 10.1159/000356869] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 10/23/2013] [Indexed: 11/19/2022] Open
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Demuyser L, Jabra-Rizk MA, Van Dijck P. Microbial cell surface proteins and secreted metabolites involved in multispecies biofilms. Pathog Dis 2014; 70:219-30. [PMID: 24376219 DOI: 10.1111/2049-632x.12123] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 12/16/2013] [Accepted: 12/16/2013] [Indexed: 12/15/2022] Open
Abstract
A considerable number of infectious diseases involve multiple microbial species coexisting and interacting in a host. Only recently however the impact of these polymicrobial diseases has been appreciated and investigated. Often, the causative microbial species are embedded in an extracellular matrix forming biofilms, a form of existence that offers protection against chemotherapeutic agents and host immune defenses. Therefore, recent efforts have focused on developing novel therapeutic strategies targeting biofilm-associated polymicrobial infections, a task that has proved to be challenging. One promising approach to inhibit the development of such complex infections is to impede the interactions between the microbial species via inhibition of adhesion. To that end, studies have focused on identifying specific cell wall adhesins and receptors involved in the interactions between the various bacterial species and the most pathogenic human fungal species Candida albicans. This review highlights the important findings from these studies and describes the available tools and techniques that have provided insights into the role of secreted molecules orchestrating microbial interactions in biofilms. Specifically, we focus on the interactions that take place in oral biofilms and the implications of these interactions on oral health and therapeutic strategies.
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Affiliation(s)
- Liesbeth Demuyser
- VIB Department of Molecular Microbiology, KU Leuven, Leuven, Belgium; Laboratory of Molecular Cell Biology, KU Leuven, Leuven, Belgium
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83
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Jakubovics NS, Yassin SA, Rickard AH. Community interactions of oral streptococci. ADVANCES IN APPLIED MICROBIOLOGY 2014; 87:43-110. [PMID: 24581389 DOI: 10.1016/b978-0-12-800261-2.00002-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
It is now clear that the most common oral diseases, dental caries and periodontitis, are caused by mixed-species communities rather than by individual pathogens working in isolation. Oral streptococci are central to these disease processes since they are frequently the first microorganisms to colonize oral surfaces and they are numerically the dominant microorganisms in the human mouth. Numerous interactions between oral streptococci and other bacteria have been documented. These are thought to be critical for the development of mixed-species oral microbial communities and for the transition from oral health to disease. Recent metagenomic studies are beginning to shed light on the co-occurrence patterns of streptococci with other oral bacteria. Refinements in microscopy techniques and biofilm models are providing detailed insights into the spatial distribution of streptococci in oral biofilms. Targeted genetic manipulation is increasingly being applied for the analysis of specific genes and networks that modulate interspecies interactions. From this work, it is clear that streptococci produce a range of extracellular factors that promote their integration into mixed-species communities and enable them to form social networks with neighboring taxa. These "community integration factors" include coaggregation-mediating adhesins and receptors, small signaling molecules such as peptides or autoinducer-2, bacteriocins, by-products of metabolism including hydrogen peroxide and lactic acid, and a range of extracellular enzymes. Here, we provide an overview of various types of community interactions between oral streptococci and other microorganisms, and we consider the possibilities for the development of new technologies to interfere with these interactions to help control oral biofilms.
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Affiliation(s)
- Nicholas S Jakubovics
- Oral Biology, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Sufian A Yassin
- Oral Biology, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Alexander H Rickard
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA
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84
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Boutin S, Bernatchez L, Audet C, Derôme N. Network analysis highlights complex interactions between pathogen, host and commensal microbiota. PLoS One 2013; 8:e84772. [PMID: 24376845 PMCID: PMC3871659 DOI: 10.1371/journal.pone.0084772] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/18/2013] [Indexed: 12/12/2022] Open
Abstract
Interactions between bacteria and their host represent a full continuum from pathogenicity to mutualism. From an evolutionary perspective, host-bacteria relationships are no longer considered a two-component system but rather a complex network. In this study, we focused on the relationship between brook charr (Salvelinus fontinalis) and bacterial communities developing on skin mucus. We hypothesized that stressful conditions such as those occurring in aquaculture production induce shifts in the bacterial community of healthy fish, thus allowing pathogens to cause infections. The results showed that fish skin mucus microbiota taxonomical structure is highly specific, its diversity being partly influenced by the surrounding water bacterial community. Two types of taxonomic co-variation patterns emerged across 121 contrasted communities’ samples: one encompassing four genera well known for their probiotic properties, the other harboring five genera mostly associated with pathogen species. The homeostasis of fish bacterial community was extensively disturbed by induction of physiological stress in that both: 1) the abundance of probiotic-like bacteria decreased after stress exposure; and 2) pathogenic bacteria increased following stress exposure. This study provides further insights regarding the role of mutualistic bacteria as a primary host protection barrier.
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Affiliation(s)
- Sébastien Boutin
- Institut de Biologie Intégrative et des Systèmes (IBIS), Département de Biologie, Université Laval, Québec, Québec, Canada
- * E-mail:
| | - Louis Bernatchez
- Institut de Biologie Intégrative et des Systèmes (IBIS), Département de Biologie, Université Laval, Québec, Québec, Canada
| | - Céline Audet
- Institut des sciences de la mer de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), Rimouski, Québec, Canada.
| | - Nicolas Derôme
- Institut de Biologie Intégrative et des Systèmes (IBIS), Département de Biologie, Université Laval, Québec, Québec, Canada
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85
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Abucayon E, Ke N, Cornut R, Patelunas A, Miller D, Nishiguchi MK, Zoski CG. Investigating catalase activity through hydrogen peroxide decomposition by bacteria biofilms in real time using scanning electrochemical microscopy. Anal Chem 2013; 86:498-505. [PMID: 24328342 DOI: 10.1021/ac402475m] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Catalase activity through hydrogen peroxide decomposition in a 1 mM bulk solution above Vibrio fischeri (γ-Protebacteria-Vibrionaceae) bacterial biofilms of either symbiotic or free-living strains was studied in real time by scanning electrochemical microscopy (SECM). The catalase activity, in units of micromoles hydrogen peroxide decomposed per minute over a period of 348 s, was found to vary with incubation time of each biofilm in correlation with the corresponding growth curve of bacteria in liquid culture. Average catalase activity for the same incubation times ranging from 1 to 12 h was found to be 0.28 ± 0.07 μmol H2O2/min for the symbiotic biofilms and 0.31 ± 0.07 μmol H2O2/min for the free-living biofilms, suggesting similar catalase activity. Calculations based on Comsol Multiphysics simulations in fitting experimental biofilm data indicated that approximately (3 ± 1) × 10(6) molecules of hydrogen peroxide were decomposed by a single bacterium per second, signifying the presence of a highly active catalase. A 2-fold enhancement in catalase activity was found for both free-living and symbiotic biofilms in response to external hydrogen peroxide concentrations as low as 1 nM in the growth media, implying a similar mechanism in responding to oxidative stress.
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Affiliation(s)
- Erwin Abucayon
- Department of Chemistry and Biochemistry, New Mexico State University , Las Cruces, New Mexico 88003, United States
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86
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Interspecies communication and periodontal disease. ScientificWorldJournal 2013; 2013:765434. [PMID: 24396307 PMCID: PMC3874309 DOI: 10.1155/2013/765434] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 09/11/2013] [Indexed: 11/18/2022] Open
Abstract
More than 500 bacterial strains may be found in dental plaque. In the beginning, the emphasis was laid on the isolation of bacteria in pure culture to define their properties. However, now, it has been well established that in nature the bacteria exist as a member of polymicrobial community or consortium of interacting species. Interactions among human oral bacteria are integral to the development and maturation of the plaque. These interactions occur at several levels including physical contact, metabolic exchange, small-signal molecule-mediated communication, and exchange of genetic material. This high level of interspecies interaction benefits the microorganism by providing a broader habitat range, effective metabolism, increasing the resistance to host defence, and enhancing their virulence. This generally has a detrimental effect on the host and is attributed to many chronic infections which poses a therapeutic challenge.
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87
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Identifying Bacterial Menu Choices from the Host Buffet during Infections. J Bacteriol 2013; 195:4989-90. [DOI: 10.1128/jb.01040-13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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88
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Probing bacterial metabolism during infection using high-resolution transcriptomics. J Bacteriol 2013; 195:4991-8. [PMID: 23974023 DOI: 10.1128/jb.00875-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A fundamental aspect of most infectious diseases is the need for the invading microbe to proliferate in the host. However, little is known about the metabolic pathways required for pathogenic microbes to colonize and persist in their hosts. In this study, we used RNA sequencing (RNA-seq) to generate a high-resolution transcriptome of the opportunistic pathogen Aggregatibacter actinomycetemcomitans in vivo. We identified 691 A. actinomycetemcomitans transcriptional start sites and 210 noncoding RNAs during growth in vivo and as a biofilm in vitro. Compared to in vitro biofilm growth on a defined medium, ∼14% of the A. actinomycetemcomitans genes were differentially regulated in vivo. A disproportionate number of genes coding for proteins involved in metabolic pathways were differentially regulated in vivo, suggesting that A. actinomycetemcomitans in vivo metabolism is distinct from in vitro growth. Mutational analyses of differentially regulated genes revealed that formate dehydrogenase H and fumarate reductase are important A. actinomycetemcomitans fitness determinants in vivo. These results not only provide a high-resolution genomic analysis of a bacterial pathogen during in vivo growth but also provide new insight into metabolic pathways required for A. actinomycetemcomitans in vivo fitness.
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89
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Jang YJ, Sim J, Jun HK, Choi BK. Differential effect of autoinducer 2 of Fusobacterium nucleatum on oral streptococci. Arch Oral Biol 2013; 58:1594-602. [PMID: 24112724 DOI: 10.1016/j.archoralbio.2013.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 08/06/2013] [Accepted: 08/11/2013] [Indexed: 11/18/2022]
Abstract
Autoinducer 2 (AI-2) is a quorum sensing molecule and plays an important role in dental biofilm formation, mediating interspecies communication and virulence expression of oral bacteria. Fusobacterium nucleatum connects early colonizing commensals and late colonizing periodontopathogens. F. nucleatum AI-2 and quorum sensing inhibitors (QSIs) can manipulate dental biofilm formation. In this study, we evaluated the effect of F. nucleatum AI-2 and QSIs on biofilm formation of Streptococcus gordonii and Streptococcus oralis, which are initial colonizers in dental biofilm. F. nucleatum AI-2 significantly enhanced biofilm growth of S. gordonii and attachment of F. nucleatum to preformed S. gordonii biofilms. By contrast, F. nucleatum AI-2 reduced biofilm growth of S. oralis and attachment of F. nucleatum to preformed S. oralis biofilms. The QSIs, (5Z)-4-bromo-5-(bromomethylene)-2(5H)-furanone and d-ribose, reversed the stimulatory and inhibitory effects of AI-2 on S. gordonii and S. oralis, respectively. In addition, co-culture using a two-compartment system showed that secreted molecules of F. nucleatum had the same effect on biofilm growth of the streptococci as AI-2. Our results demonstrate that early colonizing bacteria can influence the accretion of F. nucleatum, a secondary colonizer, which ultimately influences the binding of periodontopathogens.
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Affiliation(s)
- Yun-Ji Jang
- Department of Oral Microbiology and Immunology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
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90
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A consortium of Aggregatibacter actinomycetemcomitans, Streptococcus parasanguinis, and Filifactor alocis is present in sites prior to bone loss in a longitudinal study of localized aggressive periodontitis. J Clin Microbiol 2013; 51:2850-61. [PMID: 23784124 DOI: 10.1128/jcm.00729-13] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans-induced localized aggressive periodontitis (LAP) in African-American adolescents has been documented but is poorly understood. Two thousand fifty-eight adolescents aged 11 to 17 years were screened for their periodontal status and the presence of A. actinomycetemcomitans in their oral cavity. Seventy-one A. actinomycetemcomitans-negative and 63 A. actinomycetemcomitans-positive periodontally healthy subjects were enrolled, sampled, examined, and radiographed yearly for 3 years. Gingival and periodontal pocket depth and attachment levels were recorded. Disease presentation was characterized by bone loss (BL). Subgingival sites were sampled every 6 months to assess (i) the role of A. actinomycetemcomitans in BL and (ii) the association of A. actinomycetemcomitans and other microbes in their relationships to BL. Sixteen of 63 subjects with A. actinomycetemcomitans developed BL (the other 47 subjects with A. actinomycetemcomitans had no BL). No A. actinomycetemcomitans-negative subjects developed BL. Human oral microbe identification microarray (HOMIM) was used for subgingival microbial assessment. On a subject level, pooled data from A. actinomycetemcomitans-positive subjects who remained healthy had higher prevalences of Streptococcus and Actinomyces species, while A. actinomycetemcomitans-positive subjects with BL had higher prevalences of Parvimonas micra, Filifactor alocis, A. actinomycetemcomitans, and Peptostreptococcus sp. human oral taxon 113 (HOT-113). At vulnerable sites, A. actinomycetemcomitans, Streptococcus parasanguinis, and F. alocis levels were elevated prior to BL. In cases where the three-organism consortium (versus A. actinomycetemcomitans alone) was detected, the specificity for detecting sites of future BL increased from 62% to 99%, with a sensitivity of 89%. We conclude that detecting the presence of A. actinomycetemcomitans, S. parasanguinis, and F. alocis together indicates sites of future BL in LAP. A synergistic interaction of this consortium in LAP causation is possible and is the subject of ongoing research.
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91
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Karwacki MT, Kadouri DE, Bendaoud M, Izano EA, Sampathkumar V, Inzana TJ, Kaplan JB. Antibiofilm activity of Actinobacillus pleuropneumoniae serotype 5 capsular polysaccharide. PLoS One 2013; 8:e63844. [PMID: 23691104 PMCID: PMC3653790 DOI: 10.1371/journal.pone.0063844] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 04/09/2013] [Indexed: 12/14/2022] Open
Abstract
Cell-free extracts isolated from colony biofilms of Actinobacillus pleuropneumoniae serotype 5 were found to inhibit biofilm formation by Staphylococcus aureus, S. epidermidis and Aggregatibacter actinomycetemcomitans, but not by A. pleuropneumoniae serotype 5 itself, in a 96-well microtiter plate assay. Physical and chemical analyses indicated that the antibiofilm activity in the extract was due to high-molecular-weight polysaccharide. Extracts isolated from a mutant strain deficient in the production of serotype 5 capsular polysaccharide did not exhibit antibiofilm activity. A plasmid harboring the serotype 5 capsule genes restored the antibiofilm activity in the mutant extract. Purified serotype 5 capsular polysaccharide also exhibited antibiofilm activity against S. aureus. A. pleuropneumoniae wild-type extracts did not inhibit S. aureus growth, but did inhibit S. aureus intercellular adhesion and binding of S. aureus cells to stainless steel surfaces. Furthermore, polystyrene surfaces coated with A. pleuropneumoniae wild-type extracts, but not with capsule-mutant extracts, resisted S. aureus biofilm formation. Our findings suggest that the A. pleuropneumoniae serotype 5 capsule inhibits cell-to-cell and cell-to-surface interactions of other bacteria. A. pleuropneumoniae serotype 5 capsular polysaccharide is one of a growing number of bacterial polysaccharides that exhibit broad-spectrum, nonbiocidal antibiofilm activity. Future studies on these antibiofilm polysaccharides may uncover novel functions for bacterial polysaccharides in nature, and may lead to the development of new classes of antibiofilm agents for industrial and clinical applications.
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Affiliation(s)
- Michael T. Karwacki
- Department of Oral Biology, New Jersey Dental School, Newark, New Jersey, United States of America
| | - Daniel E. Kadouri
- Department of Oral Biology, New Jersey Dental School, Newark, New Jersey, United States of America
| | - Meriem Bendaoud
- Department of Oral Biology, New Jersey Dental School, Newark, New Jersey, United States of America
| | - Era A. Izano
- Department of Oral Biology, New Jersey Dental School, Newark, New Jersey, United States of America
| | - Vandana Sampathkumar
- Department of Oral Biology, New Jersey Dental School, Newark, New Jersey, United States of America
| | - Thomas J. Inzana
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Jeffrey B. Kaplan
- Department of Biology, American University, Washington, District of Columbia, United States of America
- * E-mail:
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92
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Da Re S, Valle J, Charbonnel N, Beloin C, Latour-Lambert P, Faure P, Turlin E, Le Bouguénec C, Renauld-Mongénie G, Forestier C, Ghigo JM. Identification of commensal Escherichia coli genes involved in biofilm resistance to pathogen colonization. PLoS One 2013; 8:e61628. [PMID: 23667443 PMCID: PMC3646849 DOI: 10.1371/journal.pone.0061628] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 03/12/2013] [Indexed: 12/24/2022] Open
Abstract
Protection provided by host bacterial microbiota against microbial pathogens is a well known but ill-understood property referred to as the barrier effect, or colonization resistance. Despite recent genome-wide analyses of host microbiota and increasing therapeutic interest, molecular analysis of colonization resistance is hampered by the complexity of direct in vivo experiments. Here we developed an in vitro-to-in vivo approach to identification of genes involved in resistance of commensal bacteria to exogenous pathogens. We analyzed genetic responses induced in commensal Escherichia coli upon entry of a diarrheagenic enteroaggregative E. coli or an unrelated Klebsiella pneumoniae pathogen into a biofilm community. We showed that pathogens trigger specific responses in commensal bacteria and we identified genes involved in limiting colonization of incoming pathogens within commensal biofilm. We tested the in vivo relevance of our findings by comparing the extent of intestinal colonization by enteroaggregative E. coli and K. pneumoniae pathogens in mice pre-colonized with E. coli wild type commensal strain, or mutants corresponding to identified colonization resistance genes. We demonstrated that the absence of yiaF and bssS (yceP) differentially alters pathogen colonization in the mouse gut. This study therefore identifies previously uncharacterized colonization resistance genes and provides new approaches to unravelling molecular aspects of commensal/pathogen competitive interactions.
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Affiliation(s)
- Sandra Da Re
- Institut Pasteur, Unité de Génétique des Biofilms, Département de Microbiologie, Paris, France
| | - Jaione Valle
- Institut Pasteur, Unité de Génétique des Biofilms, Département de Microbiologie, Paris, France
| | - Nicolas Charbonnel
- Université d'Auvergne-Clermont 1, Laboratoire de Bactériologie, Clermont-Ferrand, France
| | - Christophe Beloin
- Institut Pasteur, Unité de Génétique des Biofilms, Département de Microbiologie, Paris, France
| | - Patricia Latour-Lambert
- Institut Pasteur, Unité de Génétique des Biofilms, Département de Microbiologie, Paris, France
| | - Philippe Faure
- Université Pierre et Marie Curie, Equipe Neurophysiologie et Comportement (NPC) - UMR 7102, Paris, France
| | - Evelyne Turlin
- Institut Pasteur, Unité des Membranes Bactériennes, Département de Microbiologie, Paris, France
| | - Chantal Le Bouguénec
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, Département de Microbiologie, Paris, France
| | | | - Christiane Forestier
- Université d'Auvergne-Clermont 1, Laboratoire de Bactériologie, Clermont-Ferrand, France
| | - Jean-Marc Ghigo
- Institut Pasteur, Unité de Génétique des Biofilms, Département de Microbiologie, Paris, France
- * E-mail:
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93
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Wolcott R, Costerton J, Raoult D, Cutler S. The polymicrobial nature of biofilm infection. Clin Microbiol Infect 2013; 19:107-12. [DOI: 10.1111/j.1469-0691.2012.04001.x] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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94
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Community surveillance enhances Pseudomonas aeruginosa virulence during polymicrobial infection. Proc Natl Acad Sci U S A 2012; 110:1059-64. [PMID: 23277552 DOI: 10.1073/pnas.1214550110] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Most infections result from colonization by more than one microbe. Within such polymicrobial infections, microbes often display synergistic interactions that result in increased disease severity. Although many clinical studies have documented the occurrence of synergy in polymicrobial infections, little is known about the underlying molecular mechanisms. A prominent pathogen in many polymicrobial infections is Pseudomonas aeruginosa, a Gram-negative bacterium that displays enhanced virulence during coculture with Gram-positive bacteria. In this study we discovered that during coinfection, P. aeruginosa uses peptidoglycan shed by Gram-positive bacteria as a cue to stimulate production of multiple extracellular factors that possess lytic activity against prokaryotic and eukaryotic cells. Consequently, P. aeruginosa displays enhanced virulence in a Drosophila model of infection when cocultured with Gram-positive bacteria. Inactivation of a gene (PA0601) required for peptidoglycan sensing mitigated this phenotype. Using Drosophila and murine models of infection, we also show that peptidoglycan sensing results in P. aeruginosa-mediated reduction in the Gram-positive flora in the infection site. Our data suggest that P. aeruginosa has evolved a mechanism to survey the microbial community and respond to Gram-positive produced peptidoglycan through production of antimicrobials and toxins that not only modify the composition of the community but also enhance host killing. Additionally, our results suggest that therapeutic strategies targeting Gram-positive bacteria might be a viable approach for reducing the severity of P. aeruginosa polymicrobial infections.
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95
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Hydrogen peroxide in adaptation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:596019. [PMID: 23326624 PMCID: PMC3544357 DOI: 10.1155/2012/596019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 10/31/2012] [Indexed: 11/17/2022]
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96
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Estrela S, Trisos CH, Brown SP. From metabolism to ecology: cross-feeding interactions shape the balance between polymicrobial conflict and mutualism. Am Nat 2012; 180:566-76. [PMID: 23070318 PMCID: PMC3502068 DOI: 10.1086/667887] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Polymicrobial interactions are widespread in nature and play a major role in maintaining human health and ecosystems. Whenever one organism uses metabolites produced by another organism as energy or nutrient sources, it is called cross-feeding. The ecological outcomes of cross-feeding interactions are poorly understood and potentially diverse: mutualism, competition, exploitation, or commensalism. A major reason for this uncertainty is the lack of theoretical approaches linking microbial metabolism to microbial ecology. To address this issue, we explore the dynamics of a one-way interspecific cross-feeding interaction in which food can be traded for a service (detoxification). Our results show that diverse ecological interactions (competition, mutualism, exploitation) can emerge from this simple cross-feeding interaction and can be predicted by the metabolic, demographic, and environmental parameters that govern the balance of the costs and benefits of association. In particular, our model predicts stronger mutualism for intermediate by-product toxicity because the resource-service exchange is constrained to the service being neither too vital (high toxicity impairs resource provision) nor dispensable (low toxicity reduces need for service). These results support the idea that bridging microbial ecology and metabolism is a critical step toward a better understanding of the factors governing the emergence and dynamics of polymicrobial interactions.
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Affiliation(s)
- Sylvie Estrela
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, United Kingdom.
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97
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Huang Y, Kittichotirat W, Mayer MPA, Hall R, Bumgarner R, Chen C. Comparative genomic hybridization and transcriptome analysis with a pan-genome microarray reveal distinctions between JP2 and non-JP2 genotypes of Aggregatibacter actinomycetemcomitans. Mol Oral Microbiol 2012. [PMID: 23194436 DOI: 10.1111/omi.12005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It was postulated that the highly virulent JP2 genotype of Aggregatibacter actinomycetemcomitans may possess a constellation of distinct virulence determinants not found in non-JP2 genotypes. This study compared the genome content and the transcriptome of the serotype b JP2 genotype and the closely related serotype b non-JP2 genotype of A. actinomycetemcomitans. A custom-designed pan-genomic microarray of A. actinomycetemcomitans was constructed and validated against a panel of 11 sequenced reference strains. The microarray was subsequently used for comparative genomic hybridization of serotype b strains of JP2 (six strains) and non-JP2 (six strains) genotypes, and for transcriptome analysis of strains of JP2 (three strains) and non-JP2 (two strains). Two JP2-specific and two non-JP2-specific genomic islands were identified. In one instance, distinct genomic islands were found to be inserted into the same locus among strains of different genotypes. Transcriptome analysis identified five operons, including the leukotoxin operon, to have at least two genes with an expression ratio of 2 or greater between genotypes. Two of the differentially expressed operons were members of the membrane-bound nitrate reductase system (nap operon) and the Tol-Pal system of gram-negative bacterial species. This study is the first to demonstrate the differences in the full genome content and gene expression between A. actinomycetemcomitans strains of JP2 and non-JP2 genotypes. The information is essential for designing hypothesis-driven experiments to examine the pathogenic mechanisms of A. actinomycetemcomitans.
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Affiliation(s)
- Y Huang
- Division of Periodontology, Diagnostic Sciences and Dental Hygiene, Ostrow School of Dentistry of USC, Los Angeles, CA, USA
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98
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Hajishengallis G, Lamont RJ. Beyond the red complex and into more complexity: the polymicrobial synergy and dysbiosis (PSD) model of periodontal disease etiology. Mol Oral Microbiol 2012; 27:409-19. [PMID: 23134607 DOI: 10.1111/j.2041-1014.2012.00663.x] [Citation(s) in RCA: 742] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2012] [Indexed: 12/11/2022]
Abstract
Recent advancements in the periodontal research field are consistent with a new model of pathogenesis according to which periodontitis is initiated by a synergistic and dysbiotic microbial community rather than by select 'periopathogens', such as the 'red complex'. In this polymicrobial synergy, different members or specific gene combinations within the community fulfill distinct roles that converge to shape and stabilize a disease-provoking microbiota. One of the core requirements for a potentially pathogenic community to arise involves the capacity of certain species, termed 'keystone pathogens', to modulate the host response in ways that impair immune surveillance and tip the balance from homeostasis to dysbiosis. Keystone pathogens also elevate the virulence of the entire microbial community through interactive communication with accessory pathogens. Other important core functions for pathogenicity require the expression of diverse molecules (e.g. appropriate adhesins, cognate receptors, proteolytic enzymes and proinflammatory surface structures/ligands), which in combination act as community virulence factors to nutritionally sustain a heterotypic, compatible and proinflammatory microbial community that elicits a non-resolving and tissue-destructive host response. On the basis of the fundamental concepts underlying this model of periodontal pathogenesis, that is, polymicrobial synergy and dysbiosis, we term it the PSD model.
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Affiliation(s)
- G Hajishengallis
- Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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99
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Cammarota G, Sanguinetti M, Gallo A, Posteraro B. Review article: biofilm formation by Helicobacter pylori as a target for eradication of resistant infection. Aliment Pharmacol Ther 2012; 36:222-30. [PMID: 22650647 DOI: 10.1111/j.1365-2036.2012.05165.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 04/30/2012] [Accepted: 05/14/2012] [Indexed: 12/12/2022]
Abstract
BACKGROUND Helicobacter pylori is one of the most common causes of bacterial infection in humans. Resistance of this infection to conventional therapies has suggested the role of a biofilm-growing bacterium, which is recalcitrant to many antimicrobial agents. AIM To review the current knowledge on biofilm formation by H. pylori and to discuss the implications of this behaviour in the context of human infections and their treatment. RESULTS Scanning electron microscopy analysis of gastric biopsies of infected patients demonstrated that H. pylori forms biofilm on the gastric mucosa epithelium. Adaptation to the biofilm environment may produce many persister cells, namely dormant cells, which are highly tolerant to antimicrobials that could account for the recalcitrance of H. pylori infections in vivo. Resistant H. pylori infection has become increasingly common with triple or quadruple therapy, even in the presence of H. pylori strains susceptible to all antibiotics. The mucolytic and thiol-containing antioxidant N-acetylcysteine, associated with antibiotics, was successfully used in clinic for therapy of patients with chronic respiratory tract infections. Consistently, N-acetylcysteine treatment prior to starting antibiotic therapy allowed the disappearance of gastric biofilm in all patients in whom H. pylori was eradicated. CONCLUSION Effective strategies targeting H. pylori biofilm infections are possible, through the use of substances degrading components of the biofilm.
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Affiliation(s)
- G Cammarota
- Department of Internal Medicine, Università Cattolica del Sacro Cuore, Rome, Italy.
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The role of hydrogen peroxide in environmental adaptation of oral microbial communities. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:717843. [PMID: 22848782 PMCID: PMC3405655 DOI: 10.1155/2012/717843] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/11/2012] [Indexed: 11/17/2022]
Abstract
Oral streptococci are able to produce growth-inhibiting amounts of hydrogen peroxide (H(2)O(2)) as byproduct of aerobic metabolism. Several recent studies showed that the produced H(2)O(2) is not a simple byproduct of metabolism but functions in several aspects of oral bacterial biofilm ecology. First, the release of DNA from cells is closely associated to the production of H(2)O(2) in Streptococcus sanguinis and Streptococcus gordonii. Extracellular DNA is crucial for biofilm development and stabilization and can also serve as source for horizontal gene transfer between oral streptococci. Second, due to the growth inhibiting nature of H(2)O(2), H(2)O(2) compatible species associate with the producers. H(2)O(2) production therefore might help in structuring the initial biofilm development. On the other hand, the oral environment harbors salivary peroxidases that are potent in H(2)O(2) scavenging. Therefore, the effects of biofilm intrinsic H(2)O(2) production might be locally confined. However, taking into account that 80% of initial oral biofilm constituents are streptococci, the influence of H(2)O(2) on biofilm development and environmental adaptation might be under appreciated in current research.
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