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Factores de virulencia de Staphylococcus aureus asociados con infecciones mamarias en bovinos: relevancia y rol como agentes inmunógenos. Rev Argent Microbiol 2013; 45:119-30. [DOI: 10.1016/s0325-7541(13)70011-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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102
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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: 223] [Impact Index Per Article: 18.6] [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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103
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Lucilia sericata chymotrypsin disrupts protein adhesin-mediated staphylococcal biofilm formation. Appl Environ Microbiol 2012; 79:1393-5. [PMID: 23220967 DOI: 10.1128/aem.03689-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus and Staphylococcus epidermidis biofilms cause chronic infections due to their ability to form biofilms. The excretions/secretions of Lucilia sericata larvae (maggots) have effective activity for debridement and disruption of bacterial biofilms. In this paper, we demonstrate how chymotrypsin derived from maggot excretions/secretions disrupts protein-dependent bacterial biofilm formation mechanisms.
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104
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Carzaniga T, Antoniani D, Dehò G, Briani F, Landini P. The RNA processing enzyme polynucleotide phosphorylase negatively controls biofilm formation by repressing poly-N-acetylglucosamine (PNAG) production in Escherichia coli C. BMC Microbiol 2012; 12:270. [PMID: 23171129 PMCID: PMC3571907 DOI: 10.1186/1471-2180-12-270] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/01/2012] [Indexed: 08/05/2024] Open
Abstract
Background Transition from planktonic cells to biofilm is mediated by production of adhesion factors, such as extracellular polysaccharides (EPS), and modulated by complex regulatory networks that, in addition to controlling production of adhesion factors, redirect bacterial cell metabolism to the biofilm mode. Results Deletion of the pnp gene, encoding polynucleotide phosphorylase, an RNA processing enzyme and a component of the RNA degradosome, results in increased biofilm formation in Escherichia coli. This effect is particularly pronounced in the E. coli strain C-1a, in which deletion of the pnp gene leads to strong cell aggregation in liquid medium. Cell aggregation is dependent on the EPS poly-N-acetylglucosamine (PNAG), thus suggesting negative regulation of the PNAG biosynthetic operon pgaABCD by PNPase. Indeed, pgaABCD transcript levels are higher in the pnp mutant. Negative control of pgaABCD expression by PNPase takes place at mRNA stability level and involves the 5’-untranslated region of the pgaABCD transcript, which serves as a cis-element regulating pgaABCD transcript stability and translatability. Conclusions Our results demonstrate that PNPase is necessary to maintain bacterial cells in the planktonic mode through down-regulation of pgaABCD expression and PNAG production.
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Affiliation(s)
- Thomas Carzaniga
- Department of Biosciences, University of Milan, Via Celoria 26, Milan, 20133, Italy
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105
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Pozzi C, Wilk K, Lee JC, Gening M, Nifantiev N, Pier GB. Opsonic and protective properties of antibodies raised to conjugate vaccines targeting six Staphylococcus aureus antigens. PLoS One 2012; 7:e46648. [PMID: 23077517 PMCID: PMC3471903 DOI: 10.1371/journal.pone.0046648] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 09/03/2012] [Indexed: 01/01/2023] Open
Abstract
Staphylococcus aureus is a major cause of nosocomial and community-acquired infections for which a vaccine is greatly desired. Antigens found on the S. aureus outer surface include the capsular polysaccharides (CP) of serotype 5 (CP5) or 8 (CP8) and/or a second antigen, a β-(1→6)-polymer of N-acetyl-D-glucosamine (PNAG). Antibodies specific for either CP or PNAG antigens have excellent in vitro opsonic killing activity (OPKA), but when mixed together have potent interference in OPKA and murine protection. To ascertain if this interference could be abrogated by using a synthetic non-acetylated oligosaccharide fragment of PNAG, 9GlcNH(2), in place of chemically partially deacetylated PNAG, three conjugate vaccines consisting of 9GlcNH(2) conjugated to a non-toxic mutant of alpha-hemolysin (Hla H35L), CP5 conjugated to clumping factor B (ClfB), or CP8 conjugated to iron-surface determinant B (IsdB) were used separately to immunize rabbits. Opsonic antibodies mediating killing of multiple S. aureus strains were elicited for all three vaccines and showed carbohydrate antigen-specific reductions in the tissue bacterial burdens in animal models of S. aureus skin abscesses, pneumonia, and nasal colonization. Carrier-protein specific immunity was also shown to be effective in reducing bacterial levels in infected lungs and in nasal colonization. However, use of synthetic 9GlcNH(2) to induce antibody to PNAG did not overcome the interference in OPKA engendered when these were combined with antibody to either CP5 or CP8. Whereas each individual vaccine showed efficacy, combining antisera to CP antigens and PNAG still abrogated individual OPKA activities, indicating difficulty in achieving a multi-valent vaccine targeting both the CP and PNAG antigens.
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Affiliation(s)
- Clarissa Pozzi
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Katarzyna Wilk
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jean C. Lee
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marina Gening
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Nikolay Nifantiev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Gerald B. Pier
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
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106
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Impact of food-related environmental factors on the adherence and biofilm formation of natural Staphylococcus aureus isolates. Curr Microbiol 2012; 66:110-21. [PMID: 23064971 DOI: 10.1007/s00284-012-0247-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 09/19/2012] [Indexed: 10/27/2022]
Abstract
Staphylococcus aureus is a pathogenic bacterium capable of developing biofilms on food-processing surfaces, a pathway leading to cross contamination of foods. The purpose of this study was to investigate the influence of environmental stress factors found during seafood production on the adhesion and biofilm-forming properties of S. aureus. Adhesion and biofilm assays were performed on 26 S. aureus isolated from seafood and two S. aureus reference strains (ATCC 6538 and ATCC 43300). Cell surface properties were evaluated by affinity measurements to solvents in a partitioning test, while adhesion and biofilm assays were performed in polystyrene microplates under different stress conditions of temperature, osmolarity, and nutrient content. The expression of genes implicated in the regulation of biofilm formation (icaA, rbf and σ( B )) was analyzed by reverse transcription and quantitative real time PCR. In general, S. aureus isolates showed moderate hydrophobic properties and a marked Lewis-base character. Initial adhesion to polystyrene was positively correlated with the ionic strength of the growth medium. Most of the strains had a higher biofilm production at 37 °C than at 25 °C, promoted by the addition of glucose, whereas NaCl and MgCl(2) had a lower impact markedly affected by incubation temperatures. Principal Component Analysis revealed a considerable variability in adhesion and biofilm-forming properties between S. aureus isolates. Transcriptional analysis also indicated variations in gene expression between three characteristic isolates under different environmental conditions. These results suggested that the prevalence of S. aureus strains on food-processing surfaces is above all conditioned by the ability to adapt to the environmental stress conditions present during food production. These findings are relevant for food safety and may be of importance when choosing the safest environmental conditions and material during processing, packaging, and storage of seafood products.
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107
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Maira-Litrán T, Bentancor LV, Bozkurt-Guzel C, O'Malley JM, Cywes-Bentley C, Pier GB. Synthesis and evaluation of a conjugate vaccine composed of Staphylococcus aureus poly-N-acetyl-glucosamine and clumping factor A. PLoS One 2012; 7:e43813. [PMID: 22970144 PMCID: PMC3435376 DOI: 10.1371/journal.pone.0043813] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 07/26/2012] [Indexed: 11/18/2022] Open
Abstract
The increasing frequency, severity and antimicrobial resistance of Staphylococcus aureus infections has made the development of immunotherapies against this pathogen more urgent than ever. Previous immunization attempts using monovalent antigens resulted in at best partial levels of protection against S. aureus infection. We therefore reasoned that synthesizing a bivalent conjugate vaccine composed of two widely expressed antigens of S. aureus would result in additive/synergetic activities by antibodies to each vaccine component and/or in increased strain coverage. For this we used reductive amination, to covalently link the S. aureus antigens clumping factor A (ClfA) and deacetylated poly-N-β-(1-6)-acetyl-glucosamine (dPNAG). Mice immunized with 1, 5 or 10 µg of the dPNAG-ClfA conjugate responded in a dose-dependent manner with IgG to dPNAG and ClfA, whereas mice immunized with a mixture of ClfA and dPNAG developed significantly lower antibody titers to ClfA and no antibodies to PNAG. The dPNAG-ClfA vaccine was also highly immunogenic in rabbits, rhesus monkeys and a goat. Moreover, affinity-purified, antibodies to ClfA from dPNAG-ClfA immune serum blocked the binding of three S. aureus strains to immobilized fibrinogen. In an opsonophagocytic assay (OPKA) goat antibodies to dPNAG-ClfA vaccine, in the presence of complement and polymorphonuclear cells, killed S. aureus Newman and, to a lower extent, S. aureus Newman ΔclfA. A PNAG-negative isogenic mutant was not killed. Moreover, PNAG antigen fully inhibited the killing of S. aureus Newman by antisera to dPNAG-ClfA vaccine. Finally, mice passively vaccinated with goat antisera to dPNAG-ClfA or dPNAG-diphtheria toxoid conjugate had comparable levels of reductions of bacteria in the blood 2 h after infection with three different S. aureus strains as compared to mice given normal goat serum. In conclusion, ClfA is an immunogenic carrier protein that elicited anti-adhesive antibodies that fail to augment the OPK and protective activities of antibodies to the PNAG cell surface polysaccharide.
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Affiliation(s)
- Tomás Maira-Litrán
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.
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Poly-N-acetylglucosamine expression by wild-type Yersinia pestis is maximal at mammalian, not flea, temperatures. mBio 2012; 3:e00217-12. [PMID: 22893384 PMCID: PMC3419525 DOI: 10.1128/mbio.00217-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Numerous bacteria, including Yersinia pestis, express the poly-N-acetylglucosamine (PNAG) surface carbohydrate, a major component of biofilms often associated with a specific appearance of colonies on Congo red agar. Biofilm formation and PNAG synthesis by Y. pestis have been reported to be maximal at 21 to 28°C or “flea temperatures,” facilitating the regurgitation of Y. pestis into a mammalian host during feeding, but production is diminished at 37°C and thus presumed to be decreased during mammalian infection. Most studies of PNAG expression and biofilm formation by Y. pestis have used a low-virulence derivative of strain KIM, designated KIM6+, that lacks the pCD1 virulence plasmid, and an isogenic mutant without the pigmentation locus, which contains the hemin storage genes that encode PNAG biosynthetic proteins. Using confocal microscopy, fluorescence-activated cell sorter analysis and growth on Congo red agar, we confirmed prior findings regarding PNAG production with the KIM6+ strain. However, we found that fully virulent wild-type (WT) strains KIM and CO92 had maximal PNAG expression at 37°C, with lower PNAG production at 28°C both in broth medium and on Congo red agar plates. Notably, the typical dark colony morphology appearing on Congo red agar was maintained at 28°C, indicating that this phenotype is not associated with PNAG expression in WT Y. pestis. Extracts of WT sylvatic Y. pestis strains from the Russian Federation confirmed the maximal expression of PNAG at 37°C. PNAG production by WT Y. pestis is maximal at mammalian and not insect vector temperatures, suggesting that this factor may have a role during mammalian infection. Yersinia pestis transitions from low-temperature residence and replication in insect vectors to higher-temperature replication in mammalian hosts. Prior findings based primarily on an avirulent derivative of WT (wild-type) KIM, named KIM6+, showed that biofilm formation associated with synthesis of poly-N-acetylglucosamine (PNAG) is maximal at 21 to 28°C and decreased at 37°C. Biofilm formation was purported to facilitate the transmission of Y. pestis from fleas to mammals while having little importance in mammalian infection. Here we found that for WT strains KIM and CO92, maximal PNAG production occurs at 37°C, indicating that temperature regulation of PNAG production in WT Y. pestis is not mimicked by strain KIM6+. Additionally, we found that Congo red binding does not always correlate with PNAG production, despite its widespread use as an indicator of biofilm production. Taken together, the findings show that a role for PNAG in WT Y. pestis infection should not be disregarded and warrants further study.
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109
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Valle J, Latasa C, Gil C, Toledo-Arana A, Solano C, Penadés JR, Lasa I. Bap, a biofilm matrix protein of Staphylococcus aureus prevents cellular internalization through binding to GP96 host receptor. PLoS Pathog 2012; 8:e1002843. [PMID: 22876182 PMCID: PMC3410863 DOI: 10.1371/journal.ppat.1002843] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 06/21/2012] [Indexed: 12/15/2022] Open
Abstract
The biofilm matrix, composed of exopolysaccharides, proteins, nucleic acids and lipids, plays a well-known role as a defence structure, protecting bacteria from the host immune system and antimicrobial therapy. However, little is known about its responsibility in the interaction of biofilm cells with host tissues. Staphylococcus aureus, a leading cause of biofilm-associated chronic infections, is able to develop a biofilm built on a proteinaceous Bap-mediated matrix. Here, we used the Bap protein as a model to investigate the role that components of the biofilm matrix play in the interaction of S. aureus with host cells. The results show that Bap promotes the adhesion but prevents the entry of S. aureus into epithelial cells. A broad analysis of potential interaction partners for Bap using ligand overlayer immunoblotting, immunoprecipitation with purified Bap and pull down with intact bacteria, identified a direct binding between Bap and Gp96/GRP94/Hsp90 protein. The interaction of Bap with Gp96 provokes a significant reduction in the capacity of S. aureus to invade epithelial cells by interfering with the fibronectin binding protein invasion pathway. Consistent with these results, Bap deficient bacteria displayed an enhanced capacity to invade mammary gland epithelial cells in a lactating mice mastitis model. Our observations begin to elucidate the mechanisms by which components of the biofilm matrix can facilitate the colonization of host tissues and the establishment of persistent infections.
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Affiliation(s)
- Jaione Valle
- Laboratory of Microbial Biofilms, Idab-Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain
| | - Cristina Latasa
- Laboratory of Microbial Biofilms, Idab-Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain
| | - Carmen Gil
- Laboratory of Microbial Biofilms, Idab-Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain
| | - Alejandro Toledo-Arana
- Laboratory of Microbial Biofilms, Idab-Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain
| | - Cristina Solano
- Laboratory of Microbial Biofilms, Idab-Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain
| | - José R. Penadés
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | - Iñigo Lasa
- Laboratory of Microbial Biofilms, Idab-Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain
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110
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Hess DJ, Henry-Stanley MJ, Barnes AMT, Dunny GM, Wells CL. Ultrastructure of a novel bacterial form located in Staphylococcus aureus in vitro and in vivo catheter-associated biofilms. J Histochem Cytochem 2012; 60:770-6. [PMID: 22821688 DOI: 10.1369/0022155412457573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bacterial biofilms are ubiquitous in nature, industry, and medicine, and understanding their development and cellular structure is critical in controlling the unwanted consequences of biofilm growth. Here, we report the ultrastructure of a novel bacterial form observed by scanning electron microscopy in the luminal vegetations of catheters from patients with active Staphylococcus aureus bacteremia. This novel structure had the general appearance of a normal staphylococcal cell but up to 10 to 15 times as large. Transmission electron microscopy indicated that these structures appeared as sacs enclosing multiple normal-sized (~0.6 µm) staphylococcal forms. Using in vitro cultivated biofilms, cytochemical studies using fluorescent reagents revealed that these structures were rich in lipids and appeared within 15 min after S. aureus inoculation onto clinically relevant abiotic surfaces. Because they appeared early in biofilm development, these novel bacterial forms may represent an unappreciated mechanism for biofilm surface adherence, and their prominent lipid expression levels could explain the perplexing increased antimicrobial resistance of biofilm-associated bacteria.
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Affiliation(s)
- Donavon J Hess
- Department of Surgery, University of Minnesota, Minneapolis, MN 55455, USA
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111
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Schwartz K, Syed AK, Stephenson RE, Rickard AH, Boles BR. Functional amyloids composed of phenol soluble modulins stabilize Staphylococcus aureus biofilms. PLoS Pathog 2012; 8:e1002744. [PMID: 22685403 PMCID: PMC3369951 DOI: 10.1371/journal.ppat.1002744] [Citation(s) in RCA: 253] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 04/26/2012] [Indexed: 01/09/2023] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen that colonizes the skin and mucosal surfaces of mammals. Persistent staphylococcal infections often involve surface-associated communities called biofilms. Here we report the discovery of a novel extracellular fibril structure that promotes S. aureus biofilm integrity. Biochemical and genetic analysis has revealed that these fibers have amyloid-like properties and consist of small peptides called phenol soluble modulins (PSMs). Mutants unable to produce PSMs were susceptible to biofilm disassembly by matrix degrading enzymes and mechanical stress. Previous work has associated PSMs with biofilm disassembly, and we present data showing that soluble PSM peptides disperse biofilms while polymerized peptides do not. This work suggests the PSMs' aggregation into amyloid fibers modulates their biological activity and role in biofilms.
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Affiliation(s)
- Kelly Schwartz
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Adnan K. Syed
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Rachel E. Stephenson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Alexander H. Rickard
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Blaise R. Boles
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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112
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Abstract
Infectious diseases can be difficult to cure, especially if the pathogen forms a biofilm. After decades of extensive research into the morphology, physiology and genomics of biofilm formation, attention has recently been directed toward the analysis of the cellular metabolome in order to understand the transformation of a planktonic cell to a biofilm. Metabolomics can play an invaluable role in enhancing our understanding of the underlying biological processes related to the structure, formation and antibiotic resistance of biofilms. A systematic view of metabolic pathways or processes responsible for regulating this 'social structure' of microorganisms may provide critical insights into biofilm-related drug resistance and lead to novel treatments. This review will discuss the development of NMR-based metabolomics as a technology to study medically relevant biofilms. Recent advancements from case studies reviewed in this manuscript have shown the potential of metabolomics to shed light on numerous biological problems related to biofilms.
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Affiliation(s)
- Bo Zhang
- Department of Chemistry, University of Nebraska-Lincoln, 722 Hamilton Hall, Lincoln, NE 68588-0304, USA
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln, 722 Hamilton Hall, Lincoln, NE 68588-0304, USA
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Spiliopoulou AI, Krevvata MI, Kolonitsiou F, Harris LG, Wilkinson TS, Davies AP, Dimitracopoulos GO, Karamanos NK, Mack D, Anastassiou ED. An extracellular Staphylococcus epidermidis polysaccharide: relation to Polysaccharide Intercellular Adhesin and its implication in phagocytosis. BMC Microbiol 2012; 12:76. [PMID: 22594478 PMCID: PMC3431232 DOI: 10.1186/1471-2180-12-76] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 05/17/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The skin commensal and opportunistic pathogen Staphylococcus epidermidis is a leading cause of hospital-acquired and biomaterial-associated infections. The polysaccharide intercellular adhesin (PIA), a homoglycan composed of β-1,6-linked N-acetylglucosamine residues, synthesized by enzymes encoded in icaADBC is a major functional factor in biofilm accumulation, promoting virulence in experimental biomaterial-associated S. epidermidis infection. Extracellular mucous layer extracts of S. epidermidis contain another major polysaccharide, referred to as 20-kDa polysaccharide (20-kDaPS), composed mainly out of glucose, N-acetylglucosamine, and being partially sulfated. 20-kDaPS antiserum prevents adhesion of S. epidermidis on endothelial cells and development of experimental keratitis in rabbits. Here we provide experimental evidence that 20-kDaPS and PIA represent distinct molecules and that 20-kDaPS is implicated in endocytosis of S. epidermidis bacterial cells by human monocyte-derived macrophages. RESULTS Analysis of 75 clinical coagulase-negative staphylococci from blood-cultures and central venous catheter tips indicated that 20-kDaPS is expressed exclusively in S. epidermidis but not in other coagulase-negative staphylococcal species. Tn917-insertion in various locations in icaADBC in mutants M10, M22, M23, and M24 of S. epidermidis 1457 are abolished for PIA synthesis, while 20-kDaPS expression appears unaltered as compared to wild-type strains using specific anti-PIA and anti-20-kDaPS antisera. While periodate oxidation and dispersin B treatments abolish immuno-reactivity and intercellular adhesive properties of PIA, no abrogative activity is exerted towards 20-kDaPS immunochemical reactivity following these treatments. PIA polysaccharide I-containing fractions eluting from Q-Sepharose were devoid of detectable 20-kDaPS using specific ELISA. Preincubation of non-20-kDaPS-producing clinical strain with increasing amounts of 20-kDaPS inhibits endocytosis by human macrophages, whereas, preincubation of 20-kDaPS-producing strain ATCC35983 with 20-kDaPS antiserum enhances bacterial endocytosis by human macrophages. CONCLUSIONS In conclusion, icaADBC is not involved in 20-kDaPS synthesis, while the chemical and chromatographic properties of PIA and 20-kDaPS are distinct. 20-kDaPS exhibits anti-phagocytic properties, whereas, 20-kDaPS antiserum may have a beneficial effect on combating infection by 20-kDaPS-producing S. epidermidis.
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Affiliation(s)
- Anastasia I Spiliopoulou
- Department of Microbiology, School of Medicine, University of Patras, Patras, Greece
- Medical Microbiology and Infectious Diseases, Institute of Life Science, The College of Medicine, Swansea University, Swansea, UK
| | - Maria I Krevvata
- Department of Microbiology, School of Medicine, University of Patras, Patras, Greece
| | - Fevronia Kolonitsiou
- Department of Microbiology, School of Medicine, University of Patras, Patras, Greece
| | - Llinos G Harris
- Medical Microbiology and Infectious Diseases, Institute of Life Science, The College of Medicine, Swansea University, Swansea, UK
| | - Thomas S Wilkinson
- Medical Microbiology and Infectious Diseases, Institute of Life Science, The College of Medicine, Swansea University, Swansea, UK
| | - Angharad P Davies
- Medical Microbiology and Infectious Diseases, Institute of Life Science, The College of Medicine, Swansea University, Swansea, UK
| | | | - Nikos K Karamanos
- Laboratory of Biochemistry, Department of Chemistry, University of Patras, Patras, Greece
| | - Dietrich Mack
- Medical Microbiology and Infectious Diseases, Institute of Life Science, The College of Medicine, Swansea University, Swansea, UK
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114
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Hess DJ, Henry-Stanley MJ, Wells CL. Interplay of antibiotics and bacterial inoculum on suture-associated biofilms. J Surg Res 2012; 177:334-40. [PMID: 22682712 DOI: 10.1016/j.jss.2012.04.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 04/11/2012] [Accepted: 04/18/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND Biofilms are often antibiotic resistant, and it is unclear if prophylactic antibiotics can effectively prevent biofilm formation. Experiments were designed to test the ability of high (bactericidal) concentrations of ampicillin (AMP), vancomycin (VAN), and oxacillin (OXA) to prevent formation of suture-associated biofilms initiated with low (10(4)) and high (10(7)) numbers of Staphylococcus aureus. MATERIALS AND METHODS S. aureus biofilms were cultivated overnight on silk suture incubated in biofilm growth medium supplemented with bactericidal concentrations of AMP, VAN, or OXA. Standard microbiological methods were used to quantify total numbers of viable suture-associated S. aureus. Crystal violet staining followed by spectroscopy was used to quantify biofilm biomass, which includes bacterial cells plus matrix components. To observe the effects of antibiotics on the microscopic appearance of biofilm formation, biofilms were cultivated on glass slides, then stained with fluorescent dyes, and observed by confocal microscopy. RESULTS In the presence of a relatively low inoculum (10(4)) of S. aureus cells, bactericidal concentrations of AMP, VAN, or OXA were effective in preventing development of suture-associated biofilms. However, similar concentrations of these antibiotics were typically ineffective in preventing biofilm development on sutures inoculated with 10(7)S. aureus, a concentration relevant to contaminated skin. Confocal microscopy confirmed that bactericidal concentrations of AMP, VAN, or OXA inhibited, but did not prevent, development of S. aureus biofilms. CONCLUSION Bactericidal concentrations of AMP, VAN, or OXA inhibited formation of suture-associated biofilms initiated with low numbers (10(4)), but not high numbers (10(7)), of S. aureus cells.
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Affiliation(s)
- Donavon J Hess
- Department of Surgery, University of Minnesota, Minneapolis, USA.
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115
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Abstract
High attack rates and the ability of Staphylococcus aureus to develop resistance to all antibiotics in medical practice heightens the urgency for vaccine development. S. aureus causes many disease syndromes, including invasive disease, pneumonia, and skin and soft tissue infections. It remains unclear whether a single vaccine could protect against all of these. Vaccine composition is also challenging. Active immunization with conjugated types 5 and 8 capsular polysaccharides, an iron scavenging protein, isdB, and passive immunization against clumping factor A and lipoteichoic acid have all proven unsuccessful in clinical trials. Many experts advocate an approach using multiple antigens and have suggested that the right combination of antigens has not yet been identified. Others advocate that a successful vaccine will require antigens that work by multiple immunologic mechanisms. Targeting staphylococcal protein A and stimulating the T-helper 17 lymphocyte pathway have each received recent attention as alternative approaches to vaccination in addition to the more traditional identification of opsonophagocytic antibodies. Many questions remain as to how to successfully formulate a successful vaccine and to whom it should be deployed.
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Affiliation(s)
- Robert S Daum
- Department of Pediatrics, Section of Infectious Diseases, The University of Chicago Medical Center, Chicago, IL, USA.
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116
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Kropec A, Sava IG, Vonend C, Sakinc T, Grohmann E, Huebner J. Identification of SagA as a novel vaccine target for the prevention of Enterococcus faecium infections. Microbiology (Reading) 2011; 157:3429-3434. [DOI: 10.1099/mic.0.053207-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Infections caused by multiresistant Gram-positive bacteria represent a major health burden in the community as well as in hospitalized patients. Enterococci, especially Enterococcus faecium, are well-known pathogens of hospitalized patients and are frequently linked with resistance against multiple antibiotics, which compromises effective therapy. Rabbit immune serum raised against heat-killed E. faecium E155, a HiRECC clone, was used in an opsonophagocytic assay, an inhibition assay and a mouse bacteraemia model to identify targets of opsonic and protective antibodies. Serum against whole heat-killed bacteria was opsonic and recognized a protein of about 72 kDa that was abundantly secreted. This protein, identified as SagA by LC-ES-MS/MS, was expressed in Escherichia coli and purified. Rabbit serum raised against the purified protein showed opsonic killing activity that was inhibited by almost 100 % using 100 µg purified protein ml−1. In a mouse bacteraemia model, a statistically significant reduction of the colony counts in blood was shown with immune rabbit serum compared with preimmune serum using the homologous and a heterologous vancomycin-resistant enterococci (VRE) strain. These results indicate that SagA could be used as a promising vaccine target to treat and/or prevent VRE bacteraemia.
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Affiliation(s)
- A. Kropec
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - I. G. Sava
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - C. Vonend
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - T. Sakinc
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - E. Grohmann
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - J. Huebner
- Division of Infectious Diseases, Department of Medicine, University Medical Center Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
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117
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Poly-N-acetyl-β-(1-6)-glucosamine is a target for protective immunity against Acinetobacter baumannii infections. Infect Immun 2011; 80:651-6. [PMID: 22104104 DOI: 10.1128/iai.05653-11] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Acinetobacter baumannii has emerged as a highly troublesome, global pathogen. Treatment is complicated by high levels of antibiotic resistance, necessitating alternative means to prevent or treat A. baumannii infections. We evaluated an immunotherapeutic approach against A. baumannii, focusing on the surface polysaccharide poly-N-acetyl-β-(1-6)-glucosamine (PNAG). We used a synthetic oligosaccharide of 9 monosaccharide units (9Glc-NH(2)) conjugated to tetanus toxoid (TT) to induce antibodies in rabbits. In the presence of complement and polymorphonuclear cells, antisera to 9Glc-NH(2)-TT mediated the killing of A. baumannii S1, a high-PNAG-producing strain, but not its isogenic PNAG-negative, in-frame deletion mutant strain, S1 Δpga. Complementing the pgaABCD locus in trans in the shuttle vector pBAD18kan-ori, plasmid Δpga-c, restored the high levels of killing mediated by antibody to PNAG observed with the wild-type S1 strain. No killing was observed when normal rabbit serum (NRS) or heat-inactivated complement was used. Antiserum to 9Glc-NH(2)-TT was highly opsonic against an additional four unrelated multidrug-resistant clinical isolates of A. baumannii that synthesize various levels of surface PNAG. Using two clinically relevant models of A. baumannii infection in mice, pneumonia and bacteremia, antisera to 9Glc-NH(2)-TT significantly reduced levels of A. baumannii in the lungs or blood 2 and 24 h postinfection, respectively, compared to levels of control groups receiving NRS. This was true for all four A. baumannii strains tested. Overall, these results highlight the potential of PNAG as a vaccine component for active immunization or as a target for passive antibody immunotherapy.
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118
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Characterization of the poly-β-1,6-N-acetylglucosamine polysaccharide component of Burkholderia biofilms. Appl Environ Microbiol 2011; 77:8303-9. [PMID: 21984237 DOI: 10.1128/aem.05814-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We demonstrated the production of poly-β-1,6-N-acetylglucosamine (PNAG) polysaccharide in the biofilms of Burkholderia multivorans, Burkholderia vietnamiensis, Burkholderia ambifaria, Burkholderia cepacia, and Burkholderia cenocepacia using an immunoblot assay for PNAG. These results were confirmed by further studies, which showed that the PNAG hydrolase, dispersin B, eliminated immunoreactivity of extracts from the species that were tested (B. cenocepacia and B. multivorans). Dispersin B also inhibited biofilm formation and dispersed preformed biofilms of Burkholderia species. These results imply a role for PNAG in the maintenance of Burkholderia biofilm integrity. While PNAG was present in biofilms of all of the wild-type test organisms, a ΔpgaBC mutant of B. multivorans (Mu5) produced no detectable PNAG, indicating that these genes are needed for Burkholderia PNAG formation. Furthermore, restoration of PNAG production in PNAG negative E. coli TRXWMGΔC (ΔpgaC) by complementation with B. multivorans pgaBCD confirmed the involvement of these genes in Burkholderia PNAG production. While the confocal scanning laser microscopy of untreated wild-type B. multivorans showed thick, multilayered biofilm, Mu5 and dispersin B-treated wild-type biofilms were thin, poorly developed, and disrupted, confirming the involvement of PNAG in B. multivorans biofilm formation. Thus, PNAG appears to be an important component of Burkholderia biofilms, potentially contributing to its resistance to multiple antibiotics and persistence during chronic infections, including cystic fibrosis-associated infection.
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119
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Boles BR, Horswill AR. Staphylococcal biofilm disassembly. Trends Microbiol 2011; 19:449-55. [PMID: 21784640 DOI: 10.1016/j.tim.2011.06.004] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 06/06/2011] [Accepted: 06/16/2011] [Indexed: 01/12/2023]
Abstract
Staphylococcus aureus and Staphylococcus epidermidis are a frequent cause of biofilm-associated infections that are a tremendous burden on our healthcare system. Staphylococcal biofilms exhibit extraordinary resistance to antimicrobial killing, limiting the efficacy of antibiotic therapy, and surgical intervention is often required to remove infected tissues or implanted devices. Recent work has provided new insight into the molecular basis of biofilm development in these opportunistic pathogens. Extracellular bacterial products, environmental conditions, and polymicrobial interactions have all been shown to influence profoundly the ability of these bacteria to colonize and disperse from clinically relevant surfaces. We review new developments in staphylococcal biofilm disassembly and set them in the context of potential strategies to control biofilm infections.
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Affiliation(s)
- Blaise R Boles
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, MI 48109, USA
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120
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Zhang B, Halouska S, Schiaffo CE, Sadykov MR, Somerville GA, Powers R. NMR analysis of a stress response metabolic signaling network. J Proteome Res 2011; 10:3743-54. [PMID: 21692534 DOI: 10.1021/pr200360w] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We previously hypothesized that Staphylococcus epidermidis senses a diverse set of environmental and nutritional factors associated with biofilm formation through a modulation in the activity of the tricarboxylic acid (TCA) cycle. Herein, we report our further investigation of the impact of additional environmental stress factors on TCA cycle activity and provide a detailed description of our NMR methodology. S. epidermidis wild-type strain 1457 was treated with stressors that are associated with biofilm formation, a sublethal dose of tetracycline, 5% NaCl, 2% glucose, and autoinducer-2 (AI-2). As controls and to integrate our current data with our previous study, 4% ethanol stress and iron-limitation were also used. Consistent with our prior observations, the effect of many environmental stress factors on the S. epidermidis metabolome was essentially identical to the effect of TCA cycle inactivation in the aconitase mutant strain 1457-acnA::tetM. A detailed quantitative analysis of metabolite concentration changes using 2D (1)H-(13)C HSQC and (1)H-(1)H TOCSY spectra identified a network of 37 metabolites uniformly affected by the stressors and TCA cycle inactivation. We postulate that the TCA cycle acts as the central pathway in a metabolic signaling network.
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Affiliation(s)
- Bo Zhang
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0304, USA
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121
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Krevvata MI, Spiliopoulou A, Anastassiou ED, Karamanos N, Kolonitsiou F. Adherence of Staphylococcus epidermidis to human endothelial cells is associated with a polysaccharidic component of its extracellular mucous layer. Connect Tissue Res 2011; 52:183-9. [PMID: 20887232 DOI: 10.3109/03008207.2010.505309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Bacterial adherence to eukaryotic cells is highly contributing to microbial pathogenesis. Bacterial adhesins, macromolecules, and glycosaminoglycan chains of the endothelial cell surface have been implicated in staphylococcal attachment. Our research group has isolated an antigenic polysaccharidic component of Staphylococcus epidermidis extracellular layer, known as 20-kDa PS (PS), and showed that antibodies against this polysaccharide protect from infections. Therefore, the role of PS in S. epidermidis adherence to endothelial cells was studied. For this purpose we examined the impact of PS on the ability of two S. epidermidis strains (a PS-producing and a non-PS-producing strain) to adhere to human endothelial cells in the presence or absence of specific antibodies to this polysaccharide. Hence, it is established that exogenous chondroitin sulfate (CS) decreases, in part, the S. epidermidis' attachment to endothelial cells and the antagonistic binding effect of CS and PS was also studied. The results obtained demonstrate that PS facilitates the adherence of S. epidermidis to both strains. CS abolished the PS-induced adherence in PS-producing strain and partially in the non-PS-producing one. Conclusively, the adherence of S. epidermidis to human endothelial cells is associated with its extracellular PS component and it is suggested that the bacterial binding via glycosaminoglycan chains is an important mechanism underlining the PS-induced binding to endothelial cells.
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Affiliation(s)
- Maria I Krevvata
- Laboratory of Microbiology, School of Medicine, University of Patras, Greece
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122
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Rowe SE, Mahon V, Smith SG, O'Gara JP. A novel role for SarX in Staphylococcus epidermidis biofilm regulation. MICROBIOLOGY-SGM 2011; 157:1042-1049. [PMID: 21292751 DOI: 10.1099/mic.0.046581-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Biofilm production by staphylococci is an important virulence determinant mediated by the icaADBC-encoded polysaccharide intercellular adhesin (PIA) or by surface and extracellular proteins. Deletion of the Staphylococcus accessory regulator sarX significantly reduced biofilm-forming capacity in Staphylococcus epidermidis CSF41498, whereas multicopy sarX complemented the sarX mutant and increased wild-type biofilm production. In Staphylococcus aureus, SarX negatively regulates the accessory gene regulator (Agr) system, which in turn has strain-specific effects on biofilm regulation. Here we found that purified S. epidermidis SarX protein bound specifically to the agr P3 promoter. However RT-PCR analysis revealed that both mutation of sarX and multicopy sarX activated RNAIII transcription, making it difficult to correlate sarX-mediated biofilm regulation with altered agr activity. In contrast, RT-PCR and immunoblot analysis revealed that icaA transcription and PIA expression were decreased in the sarX mutant, whereas multicopy sarX increased ica and PIA expression. Furthermore, multicopy sarX did not promote biofilms in an icaC mutant. Finally, purified SarX protein bound specifically to the ica operon promoter. Taken together, these data reveal that the S. epidermidis SarX protein regulates the transcriptional activity of the agr and ica loci and controls the biofilm phenotype, primarily by regulating icaADBC transcription and PIA production.
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Affiliation(s)
- Sarah E Rowe
- School of Biomolecular and Biomedical Science and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Vivienne Mahon
- Department of Clinical Microbiology, St James's Hospital, Trinity College, Dublin 8, Ireland
| | - Stephen G Smith
- Department of Clinical Microbiology, St James's Hospital, Trinity College, Dublin 8, Ireland
| | - James P O'Gara
- School of Biomolecular and Biomedical Science and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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123
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Wang Y, Zhang W, Wu Z, Lu C. Reduced virulence is an important characteristic of biofilm infection of Streptococcus suis. FEMS Microbiol Lett 2011; 316:36-43. [DOI: 10.1111/j.1574-6968.2010.02189.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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124
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Resolution of Staphylococcus aureus biofilm infection using vaccination and antibiotic treatment. Infect Immun 2011; 79:1797-803. [PMID: 21220484 DOI: 10.1128/iai.00451-10] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus infections, particularly those from methicillin-resistant strains (i.e., MRSA), are reaching epidemic proportions, with no effective vaccine available. The vast number and transient expression of virulence factors in the infectious course of this pathogen have made the discovery of protective antigens particularly difficult. In addition, the divergent planktonic and biofilm modes of growth with their accompanying proteomic changes also demonstrate significant hindrances to vaccine development. In this study, a multicomponent vaccine was evaluated for its ability to clear a staphylococcal biofilm infection. Antigens (glucosaminidase, an ABC transporter lipoprotein, a conserved hypothetical protein, and a conserved lipoprotein) were chosen since they were found in previous studies to have upregulated and sustained expression in a biofilm, both in vitro and in vivo. Antibodies against these antigens were first used in microscopy studies to localize their expression in in vitro biofilms. Each of the four antigens showed heterogeneous production in various locations within the complex biofilm community in the biofilm. Based upon these studies, the four antigens were delivered simultaneously as a quadrivalent vaccine in order to compensate for this varied production. In addition, antibiotic treatment was also administered to clear the remaining nonattached planktonic cells since the vaccine antigens may have been biofilm specific. The results demonstrated that when vaccination was coupled with vancomycin treatment in a biofilm model of chronic osteomyelitis in rabbits, clinical and radiographic signs of infection significantly reduced by 67 and 82%, respectively, compared to infected animals that were either treated with vancomycin or left untreated. In contrast, vaccination alone resulted in a modest, and nonsignificant, decrease in clinical (34% reduction) and radiographic signs (9% reduction) of infection, compared to nonvaccinated animal groups untreated or treated with vancomycin. Lastly, MRSA biofilm infections were significantly cleared in 87.5% of vaccinated and antibiotic-treated animals, while antibiotics or vaccine alone could not significantly clear infection compared to controls (55.6, 22.2, and 33.3% clearance rates, respectively). This approach to vaccine development may lead to the generation of vaccines against other pathogenic biofilm bacteria.
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125
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Weaver LG, Foster M, Singh Y, Burn PL, Blanchfield JT. A Direct, Heavy Metal Free Synthesis of the ?-1,6-Linked GlcNAc Disaccharide. Aust J Chem 2011. [DOI: 10.1071/ch11055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The major component of the matrix of many bacterial biofilms is a linear polymer of β-1,6-linked units of N-acetylglucosamine (polysaccharide intercellular adhesin or poly-N-acetyl-β-1,6-d-glucosamine). In order to facilitate synthetic vaccine construction we have developed a direct, inexpensive, and biologically compatible synthesis of the minimal building block of this polymer, a β-1,6-linked GlcNAc disaccharide, namely 6-O-[2-acetamido-2-deoxy-β-d-glucopyranosyl]-2-acetamido-2-deoxy-d-glucopyranose.
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126
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127
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Lynch AS, Abbanat D. New antibiotic agents and approaches to treat biofilm-associated infections. Expert Opin Ther Pat 2010; 20:1373-87. [DOI: 10.1517/13543776.2010.505923] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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128
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Slime production by Staphylococcus aureus and Staphylococcus epidermidis strains isolated from patients with diabetic foot ulcers. Arch Immunol Ther Exp (Warsz) 2010; 58:321-4. [PMID: 20502972 DOI: 10.1007/s00005-010-0079-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/09/2009] [Indexed: 10/19/2022]
Abstract
Slime production is a very important factor related to biofilm formation. The objective of the present study was to determine the frequency of slime production by Staphylococcus aureus and Staphylococcus epidermidis strains recovered from 50 patients with diabetic foot ulcers. Slime production was determined using the Congo red agar (CRA) method and compared with immunocytochemistry for the production of polysaccharide intercellular adhesin (PIA). Out of 55 S. aureus strains, 69% produced slime as shown by the CRA method. Of them, 84.2% also produced PIA. Of 17 CRA-negative strains, 70.6% produced PIA. Out of 20 S. epidermidis strains, 75% were CRA positive and 93.3% produced PIA. All CRA-negative S. epidermidis produced PIA. In conclusion, PIA production is a very common trait of S. aureus and S. epidermidis isolates obtained from diabetic foot ulcer patients.
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129
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McCann MT, Gilmore BF, Gorman SP. Staphylococcus epidermidis device-related infections: pathogenesis and clinical management. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.60.12.0001] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Staphylococcus epidermidis, the most frequently isolated coagulase-negative staphylococcus, is the leading cause of infection related to implanted medical devices (IMDs). This is directly related to its capability to establish multilayered, highly structured biofilms on artificial surfaces. At present, conventional systemic therapies using standard antimicrobial agents represent the main strategy to treat and prevent medical device-associated infections. However, device-related infections are notoriously difficult to treat and bacteria within biofilm communities on the surface of IMDs frequently outlive treatment, and removal of the medical device is often required for successful therapy. Importantly, major advances in this research area have been made, leading to a greater understanding of the complexities of biofilm formation of S. epidermidis and resulting in significant developments in the treatment and prevention of infections related to this member of the coagulase-negative group of staphylococci. This review will examine the pathogenesis of the clinically significant S. epidermidis and provide an overview of the conventional and emerging antibiofilm approaches in the management of medical device-associated infections related to this important nosocomial pathogen.
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Affiliation(s)
- Maureen T McCann
- Maureen McCann, Brendan Gilmore, Sean Gorman: Queens University of Belfast, School of Pharmacy, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Brendan F Gilmore
- Maureen McCann, Brendan Gilmore, Sean Gorman: Queens University of Belfast, School of Pharmacy, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Sean P Gorman
- Maureen McCann, Brendan Gilmore, Sean Gorman: Queens University of Belfast, School of Pharmacy, 97 Lisburn Road, Belfast BT9 7BL, UK
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130
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Tricarboxylic acid cycle-dependent synthesis of Staphylococcus aureus Type 5 and 8 capsular polysaccharides. J Bacteriol 2010; 192:1459-62. [PMID: 20061474 DOI: 10.1128/jb.01377-09] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus capsule synthesis requires the precursor N-acetyl-glucosamine; however, capsule is synthesized during post-exponential growth when the availability of N-acetyl-glucosamine is limited. Capsule biosynthesis also requires aerobic respiration, leading us to hypothesize that capsule synthesis requires tricarboxylic acid cycle intermediates. Consistent with this hypothesis, S. aureus tricarboxylic acid cycle mutants fail to make capsule.
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131
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Synthetic {beta}-(1->6)-linked N-acetylated and nonacetylated oligoglucosamines used to produce conjugate vaccines for bacterial pathogens. Infect Immun 2009; 78:764-72. [PMID: 19948836 DOI: 10.1128/iai.01093-09] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Vaccines for pathogens usually target strain-specific surface antigens or toxins, and rarely is there broad antigenic specificity extending across multiple species. Protective antibodies for bacteria are usually specific for surface or capsular antigens. beta-(1-->6)-Poly-N-acetyl-d-glucosamine (PNAG) is a surface polysaccharide produced by many pathogens, including Staphylococcus aureus, Escherichia coli, Yersinia pestis, Bordetella pertussis, Acinetobacter baumannii, and others. Protective antibodies to PNAG are elicited when a deacetylated glycoform (deacetylated PNAG [dPNAG]; <30% acetate) is used in conjugate vaccines, whereas highly acetylated PNAG does not induce such antibodies. Chemical derivation of dPNAG from native PNAG is imprecise, so we synthesized both beta-(1-->6)-d-glucosamine (GlcNH(2)) and beta-(1-->6)-d-N-acetylglucosamine (GlcNAc) oligosaccharides with linkers on the reducing termini that could be activated to produce sulfhydryl groups for conjugation to bromoacetyl groups introduced onto carrier proteins. Synthetic 5-mer GlcNH(2) (5GlcNH(2)) or 9GlcNH(2) conjugated to tetanus toxoid (TT) elicited mouse antibodies that mediated opsonic killing of multiple S. aureus strains, while the antibodies that were produced in response to 5GlcNAc- or 9GlcNAc-TT did not mediate opsonic killing. Rabbit antibodies to 9GlcNH(2)-TT bound to PNAG and dPNAG antigens, mediated killing of S. aureus and E. coli, and protected against S. aureus skin abscesses and lethal E. coli peritonitis. Chemical synthesis of a series of oligoglucosamine ligands with defined differences in N acetylation allowed us to identify a conjugate vaccine formulation that generated protective immune responses to two of the most challenging bacterial pathogens. This vaccine could potentially be used to engender protective immunity to the broad range of pathogens that produce surface PNAG.
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132
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Rohde H, Frankenberger S, Zähringer U, Mack D. Structure, function and contribution of polysaccharide intercellular adhesin (PIA) to Staphylococcus epidermidis biofilm formation and pathogenesis of biomaterial-associated infections. Eur J Cell Biol 2009; 89:103-11. [PMID: 19913940 DOI: 10.1016/j.ejcb.2009.10.005] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Staphylococcus epidermidis is of major importance in infections associated with indwelling medical devices. The tight pathogenic association is essentially linked to the species ability to form adherent biofilms on artificial surfaces. Aiming at identifying novel targets for vaccination or therapy much effort has been made to unravel the molecular mechanisms leading to S. epidermidis biofilm formation. At present, polysaccharide intercellular adhesin (PIA) is the best studied factor involved in S. epidermidis biofilm accumulation. PIA is a glycan of beta-1,6-linked 2-acetamido-2-deoxy-D-glucopyranosyl residues of which 15 % are non-N-acetylated. PIA-producing S. epidermidis are widespread in clinical strain collections and PIA synthesis has been shown to be essential for S. epidermidis virulence. Moreover, PIA homologues have been identified in many other staphylococcal species, including the major human pathogen Staphylococcus aureus, and also Gram-negative human pathogens, suggesting that it might represent a more general pathogenicity principle in biofilm-related infections. In this review the current knowledge about the structure and biosynthesis of PIA is summarized. Additionally, information on its role in pathogenesis of biomaterial-related and other type of infections and the potential use of PIA and related compounds for prevention of infection is discussed.
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Affiliation(s)
- Holger Rohde
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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133
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Ikonomidis A, Vasdeki A, Kristo I, Maniatis AN, Tsakris A, Malizos KN, Pournaras S. Association of biofilm formation and methicillin-resistance with accessory gene regulator (agr) loci in Greek Staphylococcus aureus clones. Microb Pathog 2009; 47:341-4. [PMID: 19786085 DOI: 10.1016/j.micpath.2009.09.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 09/17/2009] [Accepted: 09/18/2009] [Indexed: 10/20/2022]
Abstract
Pathogenicity of Staphylococcus aureus is coordinated by the accessory gene regulator (agr) system. Previous studies suggested that agr Group II methicillin-resistant S. aureus (MRSA), a polymorphism that has been associated with moderate response to vancomycin, may also be related with overproduction of biofilm. In a hospital environment with endemic occurrence of MRSA, the distribution of agr groups and their association with biofilm formation was investigated. Forty-two MRSA and 32 methicillin-susceptible S. aureus (MSSA) isolates were tested and had derived from 10 genotypes and 8 clonal complexes. agr Groups I, II and IV were evenly distributed among MRSAs and MSSAs but agr Group III was not detected. agr Group II MRSAs showed significantly higher levels of biofilm production in comparison with MRSAs of the remaining agr groups as well as with all three agr groups of MSSAs. These findings suggest that agr Group II is simultaneously associated with methicillin-resistance and biofilm overproduction in a region with endemic MRSA.
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Affiliation(s)
- Alexandros Ikonomidis
- Department of Microbiology, University of Thessaly, University Hospital of Larissa, Greece.
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134
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Prenafeta A, March R, Foix A, Casals I, Costa L. Study of the humoral immunological response after vaccination with a Staphylococcus aureus biofilm-embedded bacterin in dairy cows: possible role of the exopolysaccharide specific antibody production in the protection from Staphylococcus aureus induced mastitis. Vet Immunol Immunopathol 2009; 134:208-17. [PMID: 19836084 DOI: 10.1016/j.vetimm.2009.09.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 06/15/2009] [Accepted: 09/21/2009] [Indexed: 11/25/2022]
Abstract
The objective of the present study was to analyze an extracellular component from Staphylococcus aureus (S. aureus), which we refer to as slime associated antigenic complex (SAAC), and to investigate the role of SAAC-specific antibody production in protection from S. aureus bovine mastitis. Twelve primiparous gestating cows were randomly assigned to one of the three groups: Group 1 was vaccinated with a S. aureus bacterin with very limited SAAC content; Group 2 received a S. aureus bacterin with high SAAC content and Group 3 served as unvaccinated controls. Animals were vaccinated at 45 days before the expected parturition date and revaccinated 35 days later. All groups were challenged by intramammary infusion with a virulent heterologous strain of S. aureus 23 days after calving. Antibody response against SAAC in serum and in milk, general clinical signs, mastitis score, somatic cell count (SCC) and count of S. aureus in milk were evaluated before and after challenge. Immunization with a high SAAC content in the S. aureus bacterin (Group 2) significantly enhanced antibody titers against SAAC (in serum and milk) and reduced the S. aureus concentration in milk during the post-challenge period compared to Group 1 and Group 3. Moreover, a significant negative correlation was observed between SAAC antibody production on the day of the challenge and the S. aureus count in milk by 1 day after challenge. However, there was no evidence of a difference between vaccinated and control groups with regard to clinical signs of mastitis following the challenge. Nevertheless, the SAAC antibody concentration on the day of the challenge negatively correlated with the mastitis score in quarters infected with S. aureus at 2 days post-challenge. These results indicate that the vaccines did not prevent S. aureus intramammary infection (IMI) after the experimental challenge, but immunization with a S. aureus bacterin with high SAAC content was able to reduce S. aureus multiplication in the mammary gland after challenge and suggests that the SAAC-specific antibody response could be involved in the protection against S. aureus intramammary infection. Although further studies should be performed to confirm the efficacy (under experimental conditions and in field trials), we propose bacterins from strong biofilm-producing bacteria and with high SAAC content, rather than with limited SAAC content, as a cost-efficient vaccine design against S. aureus bovine mastitis.
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Affiliation(s)
- Antoni Prenafeta
- Research and Development Department, HIPRA, 17170 Amer (Girona), Spain.
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135
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Mercier KA, Cort JR, Kennedy MA, Lockert EE, Ni S, Shortridge MD, Powers R. Structure and function of Pseudomonas aeruginosa protein PA1324 (21-170). Protein Sci 2009; 18:606-18. [PMID: 19241370 DOI: 10.1002/pro.62] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Pseudomonas aeruginosa is the prototypical biofilm-forming gram-negative opportunistic human pathogen. P. aeruginosa is causatively associated with nosocomial infections and with cystic fibrosis. Antibiotic resistance in some strains adds to the inherent difficulties that result from biofilm formation when treating P. aeruginosa infections. Transcriptional profiling studies suggest widespread changes in the proteome during quorum sensing and biofilm development. Many of the proteins found to be upregulated during these processes are poorly characterized from a functional standpoint. Here, we report the solution NMR structure of PA1324, a protein of unknown function identified in these studies, and provide a putative biological functional assignment based on the observed prealbumin-like fold and FAST-NMR ligand screening studies. PA1324 is postulated to be involved in the binding and transport of sugars or polysaccharides associated with the peptidoglycan matrix during biofilm formation.
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Affiliation(s)
- Kelly A Mercier
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
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136
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Rbf promotes biofilm formation by Staphylococcus aureus via repression of icaR, a negative regulator of icaADBC. J Bacteriol 2009; 191:6363-73. [PMID: 19684134 DOI: 10.1128/jb.00913-09] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We previously reported the identification of a gene, rbf, involved in the regulation of biofilm formation by Staphylococcus aureus 8325-4. In an effort to study the mechanism of regulation, microarrays were used to compare the transcription profiles of the wild-type strain with an rbf mutant and an rbf overexpression strain of the clinical isolate UAMS-1. Among the genes affected by rbf overexpression are those of the intercellular adhesion (ica) locus; however, expression of these genes was not affected by an rbf deletion in the chromosome. The icaADBC genes are responsible for production of poly-N-acetylglucosamine (PNAG), a major constituent of biofilm. The icaR gene encodes a negative regulator of icaADBC. In UAMS-1 carrying an Rbf-encoding plasmid, Rbf was found to repress icaR transcription with a concomitant increase in icaADBC expression and increased PNAG and biofilm production relative to isogenic strains lacking the plasmid. Sequencing of the rbf gene from UAMS-1 showed that there was a 2-bp insertion affecting the 50th codon of the rbf open reading frame, suggesting that rbf is a pseudogene in UAMS-1. This finding explains why deletion of rbf had no effect on biofilm formation in UAMS-1. To further characterize the Rbf regulation on biofilm we compared biofilm formation, icaA and icaR transcription, and PNAG production in 8325-4 and its isogenic rbf and icaR single mutants and an rbf icaR double mutant. Our results are consistent with a model wherein rbf represses synthesis of icaR, which in turn results in derepression of icaADBC and increased PNAG production. Furthermore, purified rbf did not bind to the icaR or icaA promoter region, suggesting that rbf controls expression of an unknown factor(s) that represses icaR. The role of rbf in controlling the S. aureus biofilm phenotype was further demonstrated in a clinical strain, MW2.
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137
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The pgaABCD locus of Acinetobacter baumannii encodes the production of poly-beta-1-6-N-acetylglucosamine, which is critical for biofilm formation. J Bacteriol 2009; 191:5953-63. [PMID: 19633088 DOI: 10.1128/jb.00647-09] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We found that Acinetobacter baumannii contains a pgaABCD locus that encodes proteins that synthesize cell-associated poly-beta-(1-6)-N-acetylglucosamine (PNAG). Both a mutant with an in-frame deletion of the pga locus (S1Deltapga) and a transcomplemented strain (S1Deltapga-c) of A. baumannii were constructed, and the PNAG production by these strains was compared using an immunoblot assay. Deleting the pga locus resulted in an A. baumannii strain without PNAG, and transcomplementation of the S1Deltapga strain with the pgaABCD genes fully restored the wild-type PNAG phenotype. Heterologous expression of the A. baumannii pga locus in Escherichia coli led to synthesis of significant amounts of PNAG, while no polysaccharide was detected in E. coli cells harboring an empty vector. Nuclear magnetic resonance analysis of the extracellular polysaccharide material isolated from A. baumannii confirmed that it was PNAG, but notably only 60% of the glucosamine amino groups were acetylated. PCR analysis indicated that all 30 clinical A. baumannii isolates examined had the pga genes, and immunoblot assays indicated that 14 of the 30 strains strongly produced PNAG, 14 of the strains moderately to weakly produced PNAG, and 2 strains appeared to not produce PNAG. Deletion of the pga locus led to loss of the strong biofilm phenotype, which was restored by complementation. Confocal laser scanning microscopy studies combined with COMSTAT analysis demonstrated that the biovolume, mean thickness, and maximum thickness of 16-h and 48-h-old biofilms formed by wild-type and pga-complemented A. baumannii strains were significantly greater than the biovolume, mean thickness, and maximum thickness of 16-h and 48-h-old biofilms formed by the S1Deltapga mutant strain. Biofilm-dependent production of PNAG could be an important virulence factor for this emerging pathogen that has few known virulence factors.
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138
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Stevens NT, Greene CM, O'Gara JP, Humphreys H. Biofilm characteristics of Staphylococcus epidermidis isolates associated with device-related meningitis. J Med Microbiol 2009; 58:855-862. [PMID: 19502363 DOI: 10.1099/jmm.0.009209-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus epidermidis biofilm causes device-related meningitis in neurosurgical patients. This study assessed the contribution of polysaccharide and protein to the development of a strong biofilm-positive phenotype in four S. epidermidis isolates associated with probable device-related meningitis, under varying environmental conditions. RT-PCR analysis of the intercellular adhesion operon (icaADBC) and assessment of polysaccharide intercellular adhesin (PIA) production indicated a correlation between increased icaA transcription and PIA production in ica(+) isolates grown in medium with 4 % ethanol and 4 % NaCl. Treatment of biofilm with sodium metaperiodate caused dispersion of adhered cells (P <0.0001), indicating involvement of PIA. Transcriptional levels of protein factors revealed that atlE transcription levels were similar in all isolates, whilst aap levels were variable, with induction being seen in two isolates following growth in the presence of alcohol or salt. Transcription of agr did not influence protein expression and RNAIII transcription varied among the strains. Although aap transcription was induced, the treatment of biofilm with proteinase K did not always disperse the biofilm. Our data suggest that, among the three ica(+) S. epidermidis isolates clinically associated with meningitis that were studied, PIA contributed to the strong biofilm-positive phenotype, whereas protein factors appeared to have a secondary role.
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Affiliation(s)
- Niall T Stevens
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland Education & Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | - Catherine M Greene
- Department of Medicine, Royal College of Surgeons in Ireland Education & Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | - James P O'Gara
- School of Biomolecular & Biomedical Science, University College Dublin, Dublin 4, Ireland
| | - Hilary Humphreys
- Department of Microbiology, Beaumont Hospital, Dublin 9, Ireland.,Department of Clinical Microbiology, Royal College of Surgeons in Ireland Education & Research Centre, Beaumont Hospital, Dublin 9, Ireland
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139
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Gimenez-Ibanez S, Ntoukakis V, Rathjen JP. The LysM receptor kinase CERK1 mediates bacterial perception in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2009; 4:539-41. [PMID: 19816132 PMCID: PMC2688306 DOI: 10.4161/psb.4.6.8697] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 04/08/2009] [Indexed: 05/18/2023]
Abstract
Plants use pattern recognition receptors (PRRs) to perceive pathogen-associated molecular pattern (PAMPs) and initiate defence responses. PAMP-triggered immunity (PTI) plays an important role in general resistance, and constrains the growth of most microbes on plants. Despite the importance of PRRs in plant immunity, the vast majority of them remain to be identified. We recently showed that the Arabidopsis LysM receptor kinase CERK1 is required not only for chitin signalling and fungal resistance, but plays an essential role in restricting bacterial growth on plants. We proposed that CERK1 may mediate the perception of a bacterial PAMP, or an endogenous plant cell wall component released during infection, through its extracellular carbohydrate-binding LysM-motifs. Here we report reduced activation of a PAMP-induced defence response on plants lacking the CERK1 gene after treatment with crude bacterial extracts. This demonstrates that CERK1 mediates perception of an unknown bacterial PAMP in Arabidopsis.
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140
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Mackey-Lawrence NM, Potter DE, Cerca N, Jefferson KK. Staphylococcus aureus immunodominant surface antigen B is a cell-surface associated nucleic acid binding protein. BMC Microbiol 2009; 9:61. [PMID: 19323837 PMCID: PMC2670837 DOI: 10.1186/1471-2180-9-61] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 03/26/2009] [Indexed: 01/25/2023] Open
Abstract
Background Staphylococcus aureus immunodominant surface antigen B (IsaB) elicits an immune response during septicemia and is generally classified as a virulence factor, but its biological function remains completely undefined. In an attempt to identify staphylococcal RNA-binding proteins, we designed an RNA Affinity Chromatography assay and subsequently isolated IsaB. Results Western analysis indicated that IsaB was both secreted and cell-surface associated. Gel Shift analysis confirmed the RNA binding activity but revealed that IsaB bound to any nucleic acid without sequence specificity. IsaB exhibited the highest affinity for double-stranded DNA followed by single-stranded DNA and RNA. Because extracellular DNA has been shown to play a role in biofilm formation, we investigated the biofilm-forming capacity of an isogenic isaB deletion mutant but we found that IsaB did not contribute to biofilm formation under any conditions tested. Conclusion IsaB is an extracellular nucleic acid binding protein, with little to no sequence specificity, but its role in virulence remains unclear.
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Affiliation(s)
- Nicole M Mackey-Lawrence
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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141
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Abstract
Staphylococcus aureus is an important pathogen in the hospital and in the community, and it is increasingly resistant to multiple antibiotics. A nonantimicrobial approach to controlling S aureus is needed. The most extensively tested vaccine against S aureus, which is a capsular polysaccharide-based vaccine known as StaphVAX, showed promise in an initial phase 3 trial, but was found to be ineffective in a confirmatory trial, leading to its development being halted. Likewise, a human IgG preparation known as INH-A21 (Veronate) with elevated levels of antibodies to the staphylococcal surface adhesins ClfA and SdrG made it into phase 3 testing, where it failed to show a clinical benefit. Several novel antigens are being tested for potential inclusion in a staphylococcal vaccine, including cell wall-anchored adhesin proteins and exotoxins. Given the multiple and sometimes redundant virulence factors of S aureus that enable it to be such a crafty pathogen, if a vaccine is to prove effective, it will have to be multicomponent, incorporating several surface proteins, toxoids, and surface polysaccharides.
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Affiliation(s)
- Adam C Schaffer
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, PBB-B-422, 75 Francis street, Boston, MA 02115, USA
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142
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Doern CD, Roberts AL, Hong W, Nelson J, Lukomski S, Swords WE, Reid SD. Biofilm formation by group A Streptococcus: a role for the streptococcal regulator of virulence (Srv) and streptococcal cysteine protease (SpeB). MICROBIOLOGY-SGM 2009; 155:46-52. [PMID: 19118345 DOI: 10.1099/mic.0.021048-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Recently, biofilms have become a topic of interest in the study of the human pathogen group A Streptococcus (GAS). In this study, we sought to learn more about the make-up of these structures and gain insight into biofilm regulation. Enzymic studies indicated that biofilm formation by GAS strain MGAS5005 required an extracellular protein and DNA component(s). Previous results indicated that inactivation of the transcriptional regulator Srv in MGAS5005 resulted in a significant decrease in virulence. Here, inactivation of Srv also resulted in a significant decrease in biofilm formation under both static and flow conditions. Given that production of the extracellular cysteine protease SpeB is increased in the srv mutant, we tested the hypothesis that increased levels of active SpeB may be responsible for the reduction in biofilm formation. Western immunoblot analysis indicated that SpeB was absent from MGAS5005 biofilms. Complementation of MGAS5005Deltasrv restored the biofilm phenotype and eliminated the overproduction of active SpeB. Inhibition of SpeB with E64 also restored the MGAS5005Deltasrv biofilm to wild-type levels.
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Affiliation(s)
- Christopher D Doern
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Amity L Roberts
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Wenzhou Hong
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | | | - Slawomir Lukomski
- Mary Babb Randolph Cancer Center, School of Medicine, West Virginia University, Morgantown, WV 26506, USA.,Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506, USA
| | - William E Swords
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Sean D Reid
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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143
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Leung C, Chibba A, Gómez-Biagi RF, Nitz M. Efficient synthesis and protein conjugation of β-(1→6)-d-N-acetylglucosamine oligosaccharides from the polysaccharide intercellular adhesin. Carbohydr Res 2009; 344:570-5. [DOI: 10.1016/j.carres.2008.12.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 12/22/2008] [Accepted: 12/26/2008] [Indexed: 12/24/2022]
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144
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Yamane K, Ogawa K, Yoshida M, Hayashi H, Nakamura T, Yamanaka T, Tamaki T, Hojoh H, Leung KP, Fukushima H. Identification and Characterization of Clinically Isolated Biofilm-forming Gram-positive Rods from Teeth Associated with Persistent Apical Periodontitis. J Endod 2009; 35:347-52. [DOI: 10.1016/j.joen.2008.11.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 11/25/2008] [Accepted: 11/28/2008] [Indexed: 10/21/2022]
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145
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Pérez MM, Prenafeta A, Valle J, Penadés J, Rota C, Solano C, Marco J, Grilló MJ, Lasa I, Irache JM, Maira-Litran T, Jiménez-Barbero J, Costa L, Pier GB, de Andrés D, Amorena B. Protection from Staphylococcus aureus mastitis associated with poly-N-acetyl beta-1,6 glucosamine specific antibody production using biofilm-embedded bacteria. Vaccine 2009; 27:2379-86. [PMID: 19428854 DOI: 10.1016/j.vaccine.2009.02.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 02/03/2009] [Accepted: 02/04/2009] [Indexed: 11/17/2022]
Abstract
Staphylococcus aureus vaccines based on bacterins surrounded by slime, surface polysaccharides coupled to protein carriers and polysaccharides embedded in liposomes administered together with non-biofilm bacterins confer protection against mastitis. However, it remains unknown whether protective antibodies are directed to slime-associated known exopolysaccharides and could be produced in the absence of bacterin immunizations. Here, a sheep mastitis vaccination study was carried out using bacterins, crude bacterial extracts or a purified exopolysaccharide from biofilm bacteria delivered in different vehicles. This polysaccharide reacted specifically with antibodies to poly-N-acetyl-beta-1,6-glucosamine (PNAG) and not with antibodies to other capsular antigens or bacterial components. Following intra-mammary challenge with biofilm-producing bacteria, antibody production against the polysaccharide, milk bacterial counts and mastitis lesions were determined. Bacterins from strong biofilm-producing bacteria triggered the highest production of antibodies to PNAG and conferred the highest protection against infection and mastitis, compared with weak biofilm-producing bacteria and non-cellular inocula. Thus, bacterins from strong biofilm bacteria, rather than purified polysaccharide, are proposed as a cost-efficient vaccination against S. aureus ruminant mastitis.
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Affiliation(s)
- M M Pérez
- Departamento de Sanidad Animal, SIA-CITA (DGA) Ctra. de Montañana, Zaragoza, Spain
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146
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Interconnections between Sigma B, agr, and proteolytic activity in Staphylococcus aureus biofilm maturation. Infect Immun 2009; 77:1623-35. [PMID: 19188357 DOI: 10.1128/iai.01036-08] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Staphylococcus aureus is a proficient biofilm former on host tissues and medical implants. We mutagenized S. aureus strain SH1000 to identify loci essential for ica-independent mechanisms of biofilm maturation and identified multiple insertions in the rsbUVW-sigB operon. Following construction and characterization of a sigB deletion, we determined that the biofilm phenotype was due to a lack of sigma factor B (SigB) activity. The phenotype was conserved in a sigB mutant of USA300 strain LAC, a well-studied community-associated methicillin-resistant S. aureus isolate. We determined that agr RNAIII levels were elevated in the sigB mutants, and high levels of RNAIII expression are known to have antibiofilm effects. By introducing an agr mutation into the SH1000 or LAC sigB deletion strain, S. aureus regained biofilm capacity, indicating that the biofilm phenotype was agr dependent. Protease activity is linked to agr activity and ica-independent biofilm formation, and we observed that the protease inhibitors phenylmethylsulfonyl fluoride and alpha-macroglobulin could reverse the sigB biofilm defect. Similarly, inactivating genes encoding both the aureolysin and Spl extracellular proteases in the sigB mutant restored biofilm capacity. Due to the growing link between murein hydrolase activity and biofilm maturation, autolysin zymography was performed, which revealed an altered profile in the sigB mutant; again, the phenotype could be repaired through protease inactivation. These findings indicate that the lack of SigB activity results in increased RNAIII expression, thus elevating extracellular protease levels and altering the murein hydrolase activity profile. Altogether, our observations demonstrate that SigB is an essential regulator of S. aureus biofilm maturation.
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147
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Costa AR, Henriques M, Oliveira R, Azeredo J. The role of polysaccharide intercellular adhesin (PIA) in Staphylococcus epidermidis adhesion to host tissues and subsequent antibiotic tolerance. Eur J Clin Microbiol Infect Dis 2009; 28:623-9. [PMID: 19130107 DOI: 10.1007/s10096-008-0684-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 12/01/2008] [Indexed: 10/21/2022]
Abstract
The aim of this study was to determine the role of polysaccharide intercellular adhesin (PIA) in Staphylococcus epidermidis adhesion to host tissues and subsequent antibiotic tolerance. The adherence of S. epidermidis 1457 and the mutant defective in PIA production (1457-M10) to urinary epithelium and endothelium was estimated by colony counting. Minimum bactericidal concentration and mean reduction of cellular activity (XTT) following antibiotic exposure was determined for planktonic and adhered bacteria. S. epidermidis 1457 adhered to a greater extent to both cells than the mutant strain. The adhered strains had a significantly higher antimicrobial tolerance than their planktonic counterparts. The mutant strain was, in general, the most susceptible to the antibiotics assayed. In conclusion, PIA may influence S. epidermidis adherence to host tissues and their antimicrobial susceptibility. Initial adhesion may be the main step for the acquisition of resistance in S. epidermidis.
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Affiliation(s)
- A R Costa
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, 4710-057, Braga, Portugal
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148
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Conti B, Berti F, Mercati D, Giusti F, Dallai R. The ultrastructure of malpighian tubules and the chemical composition of the cocoon ofAeolothrips intermediusBagnall (Thysanoptera). J Morphol 2009; 271:244-54. [DOI: 10.1002/jmor.10793] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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149
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Homann A, Seibel J. Chemo-enzymatic synthesis and functional analysis of natural and modified glycostructures. Nat Prod Rep 2009; 26:1555-71. [DOI: 10.1039/b909990p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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150
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Brady RA, Calhoun JH, Leid JG, Shirtliff ME. Infections of Orthopaedic Implants and Devices. SPRINGER SERIES ON BIOFILMS 2008. [DOI: 10.1007/978-3-540-68119-9_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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