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Chemmugil P, Lakshmi PTV, Annamalai A. A Multidisciplinary Study to Evaluate the Anti-quorum Sensing Ability of Phyto-compounds in Ruellia patula Jacq. Avicenna J Med Biotechnol 2019; 11:48-58. [PMID: 30800243 PMCID: PMC6359695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND Staphylococcus aureus (S. aureus) causing numerous diseases in humans, have become resistant to antibiotics, hence, urging the need for alternative medicines. METHODS In this study, the Indian medicinal weed, Ruellia patula (R. patula) extracted and fractioned through column chromatography was subjected to antibacterial and anti-quorum sensing activity against S. aureus and Methicillin Resistant Staphylococcus aureus (MRSA). RESULTS The obtained results confirmed fraction F44 to have significant effect as antimicrobial and anti-biofilm agent against both the micro-organism. Therefore, few of such highly active fractions were chemical finger printed using GC-MS and the compounds identified were further docked with DNA binding (LytTR) domain of agrA, which revealed that compounds identified from fraction were interactive to the protein. CONCLUSION R. patula is promising antimicrobial and anti-biofilm agent against S. aureus and MRSA.
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Affiliation(s)
- P Chemmugil
- Centre for Bioinformatics, Pondicherry University, Pondicherry, India
| | - PTV Lakshmi
- Centre for Bioinformatics, Pondicherry University, Pondicherry, India,Corresponding author: Lakshmi PTV, Ph.D., Centre for Bioinformatics, Pondicherry University, Pondicherry, India, Tel: +91 9486383094, E-mail:;
| | - A Annamalai
- PG and Research Department of Botany, Arignar Anna Government College, Thiruvalluvar University, Villupuram, Tamilnadu, India
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52
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Feldman M, Smoum R, Mechoulam R, Steinberg D. Antimicrobial potential of endocannabinoid and endocannabinoid-like compounds against methicillin-resistant Staphylococcus aureus. Sci Rep 2018; 8:17696. [PMID: 30523307 PMCID: PMC6283871 DOI: 10.1038/s41598-018-35793-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 11/08/2018] [Indexed: 02/06/2023] Open
Abstract
Infections caused by antibiotic-resistant strains of Staphylococcus aureus have reached epidemic proportions globally. Staphylococcal biofilms are associated with increased antimicrobial resistance and are generally less affected by host immune factors. Therefore, there is an urgent need for novel agents that not only aim at multidrug-resistant pathogens, but also ones that will act as anti biofilms. In the present study, we investigated the antimicrobial activity of the endocannabinoid (EC) anandamide (AEA) and the endocannabinoid-like (EC-like), arachidonoyl serine (AraS) against methicillin resistant S. aureus strains (MRSA). We observed a strong inhibition of biofilm formation of all tested MRSA strains as well as a notable reduction of metabolic activity of pre-formed MRSA biofilms by both agents. Moreover, staphylococcal biofilm-associated virulence determinants such as hydrophobicity, cell aggregation and spreading ability were altered by AEA and AraS. In addition, the agents were able to modify bacterial membrane potential. Importantly, both compounds prevent biofilm formation by altering the surface of the cell without killing the bacteria. Therefore, we propose that EC and EC-like compounds may act as a natural line of defence against MRSA or other antibiotic resistant bacteria. Due to their anti biofilm action these agents could also be a promising alternative to antibiotic therapeutics against biofilm-associated MRSA infections.
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Affiliation(s)
- Mark Feldman
- Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Reem Smoum
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Raphael Mechoulam
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Doron Steinberg
- Biofilm Research Laboratory, Institute of Dental Sciences, Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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53
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Vadakkan K, Choudhury AA, Gunasekaran R, Hemapriya J, Vijayanand S. Quorum sensing intervened bacterial signaling: Pursuit of its cognizance and repression. J Genet Eng Biotechnol 2018; 16:239-252. [PMID: 30733731 PMCID: PMC6353778 DOI: 10.1016/j.jgeb.2018.07.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 06/09/2018] [Accepted: 07/03/2018] [Indexed: 01/24/2023]
Abstract
Bacteria communicate within a system by means of a density dependent mechanism known as quorum sensing which regulate the metabolic and behavioral activities of a bacterial community. This sort of interaction occurs through a dialect of chemical signals called as autoinducers synthesized by bacteria. Bacterial quorum sensing occurs through various complex pathways depending upon specious diversity. Therefore the cognizance of quorum sensing mechanism will enable the regulation and thereby constrain bacterial communication. Inhibition strategies of quorum sensing are collectively called as quorum quenching; through which bacteria are incapacitated of its interaction with each other. Many virulence mechanism such as sporulation, biofilm formation, toxin production can be blocked by quorum quenching. Usually quorum quenching mechanisms can be broadly classified into enzymatic methods and non-enzymatic methods. Substantial understanding of bacterial communication and its inhibition enhances the development of novel antibacterial therapeutic drugs. In this review we have discussed the types and mechanisms of quorum sensing and various methods to inhibit and regulate density dependent bacterial communication.
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Affiliation(s)
- Kayeen Vadakkan
- Bioresource Technology Lab, Department of Biotechnology, Thiruvalluvar University, Vellore, TN 632115, India
| | - Abbas Alam Choudhury
- Bioresource Technology Lab, Department of Biotechnology, Thiruvalluvar University, Vellore, TN 632115, India
| | - Ramya Gunasekaran
- Bioresource Technology Lab, Department of Biotechnology, Thiruvalluvar University, Vellore, TN 632115, India
| | | | - Selvaraj Vijayanand
- Bioresource Technology Lab, Department of Biotechnology, Thiruvalluvar University, Vellore, TN 632115, India
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54
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Greenberg M, Kuo D, Jankowsky E, Long L, Hager C, Bandi K, Ma D, Manoharan D, Shoham Y, Harte W, Ghannoum MA, Shoham M. Small-molecule AgrA inhibitors F12 and F19 act as antivirulence agents against Gram-positive pathogens. Sci Rep 2018; 8:14578. [PMID: 30275455 PMCID: PMC6167350 DOI: 10.1038/s41598-018-32829-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 09/17/2018] [Indexed: 01/20/2023] Open
Abstract
Small-molecule antivirulence agents represent a promising alternative or adjuvant to antibiotics. These compounds disarm pathogens of disease-causing toxins without killing them, thereby diminishing survival pressure to develop resistance. Here we show that the small-molecule antivirulence agents F12 and F19 block staphylococcal transcription factor AgrA from binding to its promoter. Consequently, toxin expression is inhibited, thus preventing host cell damage by Gram-positive pathogens. Broad spectrum efficacy against Gram-positive pathogens is due to the existence of AgrA homologs in many Gram-positive bacteria. F12 is more efficacious in vitro and F19 works better in vivo. In a murine MRSA bacteremia/sepsis model, F19 treatment alone resulted in 100% survival while untreated animals had 70% mortality. Furthermore, F19 enhances antibiotic efficacy in vivo. Notably, in a murine MRSA wound infection model, combination of F19 with antibiotics resulted in bacterial load reduction. Thus, F19 could be used alone or in combination with antibiotics to prevent and treat infections of Gram-positive pathogens.
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Affiliation(s)
- Michael Greenberg
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - David Kuo
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Eckhard Jankowsky
- Center for RNA and Therapeutics, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Lisa Long
- Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Chris Hager
- Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Kiran Bandi
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Danyang Ma
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Divya Manoharan
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | | | - William Harte
- Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Mahmoud A Ghannoum
- Department of Dermatology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Menachem Shoham
- Department of Biochemistrty, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA. .,Q2 Pharma, Ltd., Haifa, Israel.
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55
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Quorum sensing system and influence on food spoilage in Pseudomonas fluorescens from turbot. Journal of Food Science and Technology 2018; 55:3016-3025. [PMID: 30065411 DOI: 10.1007/s13197-018-3222-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 03/25/2018] [Accepted: 05/10/2018] [Indexed: 10/16/2022]
Abstract
The spoilage of aquatic products is mainly caused by the bacterial growth, and the specific spoilage organism (SSO) plays an important role. Quorum sensing (QS) is a microbial cell-cell communication system which is coordinated with the population density, and is controlled by N-acyl-homoserine lactone (AHLs) as the Gram-negative bacteria communication signals. In this study, the SSO was Pseudomonas fluorescens (PF-04), isolated from the turbot (Scophthalmus maximus L.) during aerobically refrigerated storage. The supernatant extract of PF-04 tested the AHLs activities utilizing biosensor Chromobacterium violaceum CV026. AHL production was influenced by the environment temperature, and AHL production reduced obviously at 10 °C compare with 25 °C. In Luria-Bertani (LB) supplemented with 0.5-1.0% NaCl, AHL production reached the maximum. The AHL production was also regulated by pH of culture medium, acidic condition was conducive to persistent existence of the AHL molecules, but the alkaline environment would cause chemically unstable of AHL molecules. QS system in P. flurosecens played an imperative role in biofilm formation, protease and siderophore production. AHLs could regulate above three factors in PF-04. In summary, this study showed that (1) the influence of different environmental conditions (temperature, NaCl and pH) on AHL production revealed the correlation of QS in foods and (2) that proved the effect of external AHLs to regulate the biofilm formation, protease and siderophore production in PF-04.
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56
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Pigozzo AB, Missiakas D, Alonso S, Dos Santos RW, Lobosco M. Development of a Computational Model of Abscess Formation. Front Microbiol 2018; 9:1355. [PMID: 29997587 PMCID: PMC6029511 DOI: 10.3389/fmicb.2018.01355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 06/05/2018] [Indexed: 01/06/2023] Open
Abstract
In some bacterial infections, the immune system cannot eliminate the invading pathogen. In these cases, the invading pathogen is successful in establishing a favorable environment to survive and persist in the host organism. For example, S. aureus bacteria survive in organ tissues employing a set of mechanisms that work in a coordinated and highly regulated way allowing: (1) efficient impairment of the immune response; and (2) protection from the immune cells and molecules. S. aureus secretes several proteins including coagulases and toxins that drive abscess formation and persistence. Unless staphylococcal abscesses are surgically drained and treated with antibiotics, disseminated infection and septicemia produce a lethal outcome. Within this context, this paper develops a simple mathematical model of abscess formation incorporating characteristics that we judge important for an abscess to be formed. Our aim is to build a mathematical model that reproduces some characteristics and behaviors that are observed in the process of abscess formation.
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Affiliation(s)
- Alexandre B Pigozzo
- Department of Computer Science, Federal University of São João Del-Rei, São João Del-Rei, Brazil
| | - Dominique Missiakas
- Department of Microbiology, University of Chicago, Chicago, IL, United States
| | - Sergio Alonso
- Department of Physics, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - Rodrigo W Dos Santos
- Graduate Program in Computational Modeling, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Marcelo Lobosco
- Graduate Program in Computational Modeling, Federal University of Juiz de Fora, Juiz de Fora, Brazil
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57
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Choudhary KS, Mih N, Monk J, Kavvas E, Yurkovich JT, Sakoulas G, Palsson BO. The Staphylococcus aureus Two-Component System AgrAC Displays Four Distinct Genomic Arrangements That Delineate Genomic Virulence Factor Signatures. Front Microbiol 2018; 9:1082. [PMID: 29887846 PMCID: PMC5981134 DOI: 10.3389/fmicb.2018.01082] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/07/2018] [Indexed: 01/24/2023] Open
Abstract
Two-component systems (TCSs) consist of a histidine kinase and a response regulator. Here, we evaluated the conservation of the AgrAC TCS among 149 completely sequenced Staphylococcus aureus strains. It is composed of four genes: agrBDCA. We found that: (i) AgrAC system (agr) was found in all but one of the 149 strains, (ii) the agr positive strains were further classified into four agr types based on AgrD protein sequences, (iii) the four agr types not only specified the chromosomal arrangement of the agr genes but also the sequence divergence of AgrC histidine kinase protein, which confers signal specificity, (iv) the sequence divergence was reflected in distinct structural properties especially in the transmembrane region and second extracellular binding domain, and (v) there was a strong correlation between the agr type and the virulence genomic profile of the organism. Taken together, these results demonstrate that bioinformatic analysis of the agr locus leads to a classification system that correlates with the presence of virulence factors and protein structural properties.
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Affiliation(s)
- Kumari S Choudhary
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - Nathan Mih
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Bioinformatics and Systems Biology Program, University of California, San Diego, San Diego, CA, United States
| | - Jonathan Monk
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - Erol Kavvas
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States
| | - James T Yurkovich
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Bioinformatics and Systems Biology Program, University of California, San Diego, San Diego, CA, United States
| | - George Sakoulas
- Department of Pediatrics, University of California, San Diego, San Diego, CA, United States
| | - Bernhard O Palsson
- Systems Biology Research Group, Department of Bioengineering, University of California, San Diego, San Diego, CA, United States.,Bioinformatics and Systems Biology Program, University of California, San Diego, San Diego, CA, United States.,Department of Pediatrics, University of California, San Diego, San Diego, CA, United States
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58
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A Quorum Sensing-Regulated Protein Binds Cell Wall Components and Enhances Lysozyme Resistance in Streptococcus pyogenes. J Bacteriol 2018; 200:JB.00701-17. [PMID: 29555699 DOI: 10.1128/jb.00701-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/10/2018] [Indexed: 12/28/2022] Open
Abstract
The Rgg2/3 quorum sensing (QS) system is conserved among all sequenced isolates of group A Streptococcus (GAS; Streptococcus pyogenes). The molecular architecture of the system consists of a transcriptional activator (Rgg2) and a transcriptional repressor (Rgg3) under the control of autoinducing peptide pheromones (SHP2 and SHP3). Activation of the Rgg2/3 pathway leads to increases in biofilm formation and resistance to the bactericidal effects of the host factor lysozyme. In this work, we show that deletion of a small gene, spy49_0414c, abolished both phenotypes in response to pheromone signaling. The gene encodes a small, positively charged, secreted protein, referred to as StcA. Analysis of recombinant StcA showed that it can directly interact with GAS cell wall preparations containing phosphodiester-linked carbohydrate polymers but not with preparations devoid of them. Immunofluorescence microscopy detected antibody against StcA bound to the surface of paraformaldehyde-fixed wild-type cells. Expression of StcA in bacterial culture induced a shift in the electrostatic potential of the bacterial cell surface, which became more positively charged. These results suggest that StcA promotes phenotypes by way of ionic interactions with the GAS cell wall, most likely with negatively charged cell wall-associated polysaccharides.IMPORTANCE This study focuses on a small protein, StcA, that is expressed and secreted under induction of Rgg2/3 QS, ionically associating with negatively charged domains on the cell surface. These data present a novel mechanism of resistance to the host factor lysozyme by GAS and have implications in the relevance of this circuit in the interaction between the bacterium and the human host that is mediated by the bacterial cell surface.
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59
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Thomsen IP, Liu GY. Targeting fundamental pathways to disrupt Staphylococcus aureus survival: clinical implications of recent discoveries. JCI Insight 2018. [PMID: 29515041 DOI: 10.1172/jci.insight.98216] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The emergence of community-associated methicillin-resistant Staphylococcus aureus during the past decade along with an impending shortage of effective antistaphylococcal antibiotics have fueled impressive advances in our understanding of how S. aureus overcomes the host environment to establish infection. Backed by recent technologic advances, studies have uncovered elaborate metabolic, nutritional, and virulence strategies deployed by S. aureus to survive the restrictive and hostile environment imposed by the host, leading to a plethora of promising antimicrobial approaches that have potential to remedy the antibiotic resistance crisis. In this Review, we highlight some of the critical and recently elucidated bacterial strategies that are potentially amenable to intervention, discuss their relevance to human diseases, and address the translational challenges posed by current animal models.
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Affiliation(s)
- Isaac P Thomsen
- Department of Pediatrics, Division of Pediatric Infectious Diseases, and Vanderbilt Vaccine Research Program, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George Y Liu
- Division of Pediatric Infectious Diseases and Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
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60
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Karathanasi G, Bojer MS, Baldry M, Johannessen BA, Wolff S, Greco I, Kilstrup M, Hansen PR, Ingmer H. Linear peptidomimetics as potent antagonists of Staphylococcus aureus agr quorum sensing. Sci Rep 2018; 8:3562. [PMID: 29476092 PMCID: PMC5824847 DOI: 10.1038/s41598-018-21951-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 02/14/2018] [Indexed: 01/27/2023] Open
Abstract
Staphylococcus aureus is an important pathogen causing infections in humans and animals. Increasing problems with antimicrobial resistance has prompted the development of alternative treatment strategies, including antivirulence approaches targeting virulence regulation such as the agr quorum sensing system. agr is naturally induced by cyclic auto-inducing peptides (AIPs) binding to the AgrC receptor and cyclic peptide inhibitors have been identified competing with AIP binding to AgrC. Here, we disclose that small, linear peptidomimetics can act as specific and potent inhibitors of the S. aureus agr system via intercepting AIP-AgrC signal interaction at low micromolar concentrations. The corresponding linear peptide did not have this ability. This is the first report of a linear peptide-like molecule that interferes with agr activation by competitive binding to AgrC. Prospectively, these peptidomimetics may be valuable starting scaffolds for the development of new inhibitors of staphylococcal quorum sensing and virulence gene expression.
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Affiliation(s)
- Georgia Karathanasi
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark
| | - Martin Saxtorph Bojer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark
| | - Mara Baldry
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark
| | - Bárdur Andréson Johannessen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark
| | - Sanne Wolff
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark
| | - Ines Greco
- Department of Drug Design and Farmacology, Faculty of Health and Medical Sciences University of Copenhagen, Universitetsparken 2, 2100, København, Denmark
| | - Mogens Kilstrup
- Department of Biotechnology and Biomedicine, Metabolic Signaling and Regulation, Technical University of Denmark, Matematiktorvet, 2800, Lyngby, Denmark
| | - Paul Robert Hansen
- Department of Drug Design and Farmacology, Faculty of Health and Medical Sciences University of Copenhagen, Universitetsparken 2, 2100, København, Denmark
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark.
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61
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Kong C, Chee CF, Richter K, Thomas N, Abd Rahman N, Nathan S. Suppression of Staphylococcus aureus biofilm formation and virulence by a benzimidazole derivative, UM-C162. Sci Rep 2018; 8:2758. [PMID: 29426873 PMCID: PMC5807447 DOI: 10.1038/s41598-018-21141-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/30/2018] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus is a major cause of nosocomial infections and secretes a diverse spectrum of virulence determinants as well as forms biofilm. The emergence of antibiotic-resistant S. aureus highlights the need for alternative forms of therapeutics other than conventional antibiotics. One route to meet this need is screening small molecule derivatives for potential anti-infective activity. Using a previously optimized C. elegans – S. aureus small molecule screen, we identified a benzimidazole derivative, UM-C162, which rescued nematodes from a S. aureus infection. UM-C162 prevented the formation of biofilm in a dose-dependent manner without interfering with bacterial viability. To examine the effect of UM-C162 on the expression of S. aureus virulence genes, a genome-wide transcriptome analysis was performed on UM-C162-treated pathogen. Our data indicated that the genes associated with biofilm formation, particularly those involved in bacterial attachment, were suppressed in UM-C162-treated bacteria. Additionally, a set of genes encoding vital S. aureus virulence factors were also down-regulated in the presence of UM-C162. Further biochemical analysis validated that UM-C162-mediated disruption of S. aureus hemolysins, proteases and clumping factors production. Collectively, our findings propose that UM-C162 is a promising compound that can be further developed as an anti-virulence agent to control S. aureus infections.
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Affiliation(s)
- Cin Kong
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi Selangor, Malaysia.,Department of Biomedical Sciences, Faculty of Science, University of Nottingham Malaysia Campus, 43500, Semenyih, Selangor, Malaysia
| | - Chin-Fei Chee
- Nanotechnology & Catalysis Research Centre, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Katharina Richter
- Department of Surgery, Basil Hetzel Institute for Translational Health Research, The University of Adelaide, Adelaide, South Australia, Australia.,Adelaide Biofilm Test Facility, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
| | - Nicky Thomas
- Adelaide Biofilm Test Facility, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia.,School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Noorsaadah Abd Rahman
- Department of Chemistry, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi Selangor, Malaysia.
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62
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Tan L, Li SR, Jiang B, Hu XM, Li S. Therapeutic Targeting of the Staphylococcus aureus Accessory Gene Regulator ( agr) System. Front Microbiol 2018; 9:55. [PMID: 29422887 PMCID: PMC5789755 DOI: 10.3389/fmicb.2018.00055] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/10/2018] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus aureus can cause numerous different diseases, which has been attributed to its large repertoire of virulence factors, many of which are under the control of the accessory gene regulator (agr) quorum sensing system. Under conditions of high cell density, agr increases the production of many virulence factors, decreases expression of several colonization factors, and is intimately associated with the pathogenesis and biofilm formation of S. aureus. This review summarizes our current understanding of the molecular mechanisms underlying agr quorum sensing and the regulation of agr expression. The discussion also examines subgroups of agr and their association with different diseases, and concludes with an analysis of strategies for designing drugs and vaccines that target agr to combat S. aureus infections.
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Affiliation(s)
- Li Tan
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Si Rui Li
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Bei Jiang
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Xiao Mei Hu
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Shu Li
- Department of Microbiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
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63
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Targeting Virulence in Staphylococcus aureus by Chemical Inhibition of the Accessory Gene Regulator System In Vivo. mSphere 2018; 3:mSphere00500-17. [PMID: 29359191 PMCID: PMC5770542 DOI: 10.1128/msphere.00500-17] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) presents one of the most serious health concerns worldwide. The WHO labeled it as a “high-priority” pathogen in 2017, also citing the more recently emerged vancomycin-intermediate and -resistant strains. Methicillin-resistant Staphylococcus aureus (MRSA) presents one of the most serious health concerns worldwide. The WHO labeled it as a “high-priority” pathogen in 2017, also citing the more recently emerged vancomycin-intermediate and -resistant strains. With the spread of antibiotic resistance due in large part to the selective pressure exerted by conventional antibiotics, the use of antivirulence strategies has been recurrently proposed as a promising therapeutic approach. In MRSA, virulence is chiefly controlled by quorum sensing (QS); inhibitors of QS are called quorum quenchers (QQ). In S. aureus, the majority of QS components are coded for by the accessory gene regulator (Agr) system. Although much work has been done to develop QQs against MRSA, only a few studies have progressed to in vivo models. Those studies include both prophylactic and curative models of infection as well as combination treatments with antibiotic. For most, high efficacy is seen at attenuating MRSA virulence and pathogenicity, with some studies showing effects such as synergy with antibiotics and antibiotic resensitization. This minireview aims to summarize and derive conclusions from the literature on the in vivo efficacy of QQ agents in MRSA infection models. In vitro data are also summarized to provide sufficient background on the hits discussed. On the whole, the reported in vivo effects of the reviewed QQs against MRSA represent positive progress at this early stage in drug development. Follow-up studies that thoroughly examine in vitro and in vivo activity are needed to propel the field forward and set the stage for lead optimization.
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Schelin J, Susilo YB, Johler S. Expression of Staphylococcal Enterotoxins under Stress Encountered during Food Production and Preservation. Toxins (Basel) 2017; 9:E401. [PMID: 29244757 PMCID: PMC5744121 DOI: 10.3390/toxins9120401] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/12/2017] [Accepted: 12/14/2017] [Indexed: 12/24/2022] Open
Abstract
Staphylococcal food poisoning (SFP) is the most prevalent cause of food-borne intoxications worldwide. Consumption of enterotoxins preformed in food causes violent vomiting and can be fatal in children and the elderly. While being repressed by competing bacteria in most matrices, Staphylococcus aureus benefits from crucial competitive advantages in foods with high osmolarity or low pH. During recent years, the long-standing belief in the feasibility of assessing SFP risk based on colony-forming units of S. aureus present in food products has been disproven. Instead, researchers and food business operators are acutely aware of the imminent threat arising from unforeseeable enterotoxin production under stress conditions. This paradigm shift led to a variety of new publications enabling an improved understanding of enterotoxin expression under stress conditions encountered in food. The wealth of data provided by these studies is extremely diverse, as it is based on different methodological approaches, staphylococcal strains, stressors, and enterotoxins. Therefore, in this review, we aggregated and critically evaluated the complex findings of these studies, to provide readers with a current overview of the state of research in the field.
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Affiliation(s)
- Jenny Schelin
- Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
| | - Yusak Budi Susilo
- Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
| | - Sophia Johler
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland.
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Forestier C, Billard E, Milon G, Gueirard P. Unveiling and Characterizing Early Bilateral Interactions between Biofilm and the Mouse Innate Immune System. Front Microbiol 2017; 8:2309. [PMID: 29209305 PMCID: PMC5702342 DOI: 10.3389/fmicb.2017.02309] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/08/2017] [Indexed: 12/20/2022] Open
Abstract
A very substantial progress has been made in our understanding of infectious diseases caused by invasive bacteria. Under their planktonic forms, bacteria transiently reside in the otherwise sterile mammal body tissues, as the physiological inflammation insures both their clearance and repair of any tissue damage. Yet, the bacteria prone to experience planktonic to biofilm developmental transition still need to be studied. Of note, sessile bacteria not only persist but also concur preventing the effectors and regulators of the physiological inflammation to operate. Thus, it is urgent to design biologically sound experimental approaches aimed to extract, at the earliest stage, immune signatures of mono-bacteria planktonic to biofilm developmental transition in vivo and ex vivo. Indeed, the transition is often the first event to which succeeds the “chronicization” process whereby classical bacteria-targeting therapies are no more efficacious. An in vivo model of micro-injection of Staphylococcus aureus planktonic or biofilm cells in the ear pinna dermis of laboratory transgenic mice with fluorescent immune cells is proposed. It allows visualizing, in real time, the range of the early interactions between the S. aureus and myeloid cell subsets- the resident macrophages and dendritic cells, the recruited neutrophil granulocytes/polymorphonuclear neutrophils, monocytes otherwise known to differentiate as macrophages or dendritic cells. One main objective is to extract contrasting immune signatures of the modulation of the physiological inflammation with respect to the two bacterial lifestyles.
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Affiliation(s)
- Christiane Forestier
- CNRS UMR 6023, Laboratoire Microorganismes: Génome et Environnement, Université Clermont-Auvergne, Clermont-Ferrand, France
| | - Elisabeth Billard
- INRA USC 2018, Inserm U1071, Laboratoire Microbes Intestin Inflammation et Susceptibilité de l'Hôte, Université Clermont-Auvergne, Clermont-Ferrand, France
| | | | - Pascale Gueirard
- CNRS UMR 6023, Laboratoire Microorganismes: Génome et Environnement, Université Clermont-Auvergne, Clermont-Ferrand, France
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Susilo YB, Sihto HM, Rådström P, Stephan R, Johler S, Schelin J. Reduced Enterotoxin D Formation on Boiled Ham in Staphylococcus Aureus Δagr Mutant. Toxins (Basel) 2017; 9:E263. [PMID: 28841182 PMCID: PMC5618196 DOI: 10.3390/toxins9090263] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 08/21/2017] [Accepted: 08/24/2017] [Indexed: 11/16/2022] Open
Abstract
Staphylococcal food poisoning (SFP) is a common cause of foodborne illness worldwide, and enterotoxin D (SED) is one of the most frequent Staphylococcus aureus enterotoxins associated with it. It has been reported that the expression and formation of SED in S. aureus is regulated by the quorum sensing Agr system. In this study, the effect of agr deletion on sed expression in S. aureus grown on boiled ham was investigated. Growth, sed mRNA and SED protein levels in an S. aureus wild type strain and its isogenic Δagr mutant were monitored for 14 days at 22 °C. The results showed that although deletion of the agr gene did not affect the growth rate or maximum cell density of S. aureus on boiled ham, it had a pronounced effect on SED formation during the first 5 days of incubation. The SED concentration was not reflected in the amount of preceding sed transcripts, suggesting that sed transcription levels may not always reflect SED formation. The expression of RNAIII transcript, the regulatory signal of the Agr system, was also monitored. Similar transcription patterns were observed for RNAIII and sed. Surprisingly, in the Δagr mutant, sed expression was comparable to that in the wild type strain, and was thus unaffected by deletion of the Agr system. These results demonstrate that the Agr system appears to only partially affect SED formation, even in a real food environment.
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Affiliation(s)
- Yusak Budi Susilo
- Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
| | - Henna-Maria Sihto
- Institute for Food Safety and Hygiene, University of Zurich, CH-8057 Zurich, Switzerland.
| | - Peter Rådström
- Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
| | - Roger Stephan
- Institute for Food Safety and Hygiene, University of Zurich, CH-8057 Zurich, Switzerland.
| | - Sophia Johler
- Institute for Food Safety and Hygiene, University of Zurich, CH-8057 Zurich, Switzerland.
| | - Jenny Schelin
- Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
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Rajput A, Kumar M. Computational Exploration of Putative LuxR Solos in Archaea and Their Functional Implications in Quorum Sensing. Front Microbiol 2017; 8:798. [PMID: 28515720 PMCID: PMC5413776 DOI: 10.3389/fmicb.2017.00798] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/19/2017] [Indexed: 11/13/2022] Open
Abstract
LuxR solos are unexplored in Archaea, despite their vital role in the bacterial regulatory network. They assist bacteria in perceiving acyl homoserine lactones (AHLs) and/or non-AHLs signaling molecules for establishing intraspecies, interspecies, and interkingdom communication. In this study, we explored the potential LuxR solos of Archaea from InterPro v62.0 meta-database employing taxonomic, probable function, distribution, and evolutionary aspects to decipher their role in quorum sensing (QS). Our bioinformatics analyses showed that putative LuxR solos of Archaea shared few conserved domains with bacterial LuxR despite having less similarity within proteins. Functional characterization revealed their ability to bind various AHLs and/or non-AHLs signaling molecules that involve in QS cascades alike bacteria. Further, the phylogenetic study indicates that Archaeal LuxR solos (with less substitution per site) evolved divergently from bacteria and share distant homology along with instances of horizontal gene transfer. Moreover, Archaea possessing putative LuxR solos, exhibit the correlation between taxonomy and ecological niche despite being the inhabitant of diverse habitats like halophilic, thermophilic, barophilic, methanogenic, and chemolithotrophic. Therefore, this study would shed light in deciphering the role of the putative LuxR solos of Archaea to adapt varied habitats via multilevel communication with other organisms using QS.
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Affiliation(s)
- Akanksha Rajput
- Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial ResearchChandigarh, India
| | - Manoj Kumar
- Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial ResearchChandigarh, India
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Gomes-Fernandes M, Laabei M, Pagan N, Hidalgo J, Molinos S, Villar Hernandez R, Domínguez-Villanueva D, Jenkins ATA, Lacoma A, Prat C. Accessory gene regulator (Agr) functionality in Staphylococcus aureus derived from lower respiratory tract infections. PLoS One 2017; 12:e0175552. [PMID: 28410390 PMCID: PMC5391941 DOI: 10.1371/journal.pone.0175552] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 03/28/2017] [Indexed: 01/09/2023] Open
Abstract
Objective Characterization of Staphylococcus aureus clinical isolates derived from lower respiratory tract infections (LRTIs), and correlation between the functionality of the accessory gene regulator (Agr) and genotypic and phenotypic characteristics, clinical variables and clinical outcome. Methods S aureus isolates derived from LRTIs and control groups (nasal carriage and bacteraemia) were genotyped using StaphyType DNA microarray. Agr activity was evaluated using the CAMP synergistic haemolysis assay and the Vesicle Lysis Test (VLT). Discordant strains were analysed by quantitative reverse-transcriptase real-time PCR (qRT-PCR). Results Agr was functional in 79.7% and 84.5% of strains according to the CAMP and VLT assays respectively. Higher concordance with RNAIII expression measured by qRT-PCR was observed with the VLT assay (76.2%) compared with the CAMP assay (23.8%). No statistically significant differences were observed in Agr functionality between the study groups, nor the phenotypical/genotypical bacterial characteristics. No association between increased mortality/respiratory complications and Agr function was observed. Conclusions Agr activity was high (82.2%) in isolates from LRTIs suggesting the importance of this global regulator in lower respiratory tract colonisation and infection. However, equally high Agr activity was observed in isolates derived from nasal carriage and bacteraemia, contradictory to previous observations. Agr functionality measured by the VLT assay was superior to CAMP assay.
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Affiliation(s)
- Meissiner Gomes-Fernandes
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CAPES Foundation, Ministry of Education of Brazil, Brasília, Brazil
| | - Maisem Laabei
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Natalia Pagan
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Jessica Hidalgo
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Sònia Molinos
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Raquel Villar Hernandez
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Dídac Domínguez-Villanueva
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
| | | | - Alicia Lacoma
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CIBER Enfermedades Respiratorias, CIBER, Instituto de Salud Carlos III, Badalona, Spain
| | - Cristina Prat
- Microbiology Department, Hospital Universitari Germans Trias i Pujol, Institut d’ Investigació Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain
- CIBER Enfermedades Respiratorias, CIBER, Instituto de Salud Carlos III, Badalona, Spain
- * E-mail:
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An TJ, Benvenuti MA, Mignemi ME, Martus J, Wood JB, Thomsen IP, Schoenecker JG. Similar Clinical Severity and Outcomes for Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Pediatric Musculoskeletal Infections. Open Forum Infect Dis 2017; 4:ofx013. [PMID: 28480284 PMCID: PMC5414090 DOI: 10.1093/ofid/ofx013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/24/2017] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Prior studies of pediatric musculoskeletal infection have suggested that methicillin-resistant Staphylococcus aureus (MRSA) infections result in worse outcomes compared with infections with methicillin-susceptible S aureus (MSSA) strains. Based on these results, clinical prediction algorithms have been developed to differentiate between MRSA and MSSA early in a patient's clinical course. This study compares hospital outcomes for pediatric patients with MRSA and MSSA musculoskeletal infection presenting to the emergency department at a large tertiary care children's hospital. METHODS A retrospective study identified pediatric patients with S aureus musculoskeletal infection over a 5-year period (2008-2013) by sequential review of all pediatric orthopedic consults. Relevant demographic information, laboratory values, and clinical outcomes were obtained from the electronic medical record. RESULTS Of the 91 identified cases of S aureus pediatric musculoskeletal infection, there were 49 cases of MRSA infection (53%) and 42 cases of MSSA infection (47%). There were no significant differences between MRSA and MSSA infections in median hospital length of stay (4.8 vs 5.7 days, P = .50), febrile days (0.0 vs 1.5 days, P = .10), and antibiotic duration (28 vs 34 days, P = .18). Methicillin-resistant S aureus infections were more likely to require operative intervention than MSSA infection (85% vs 62%, P = .15). A logistic regression model based on C-reactive protein, temperature, white blood cell count, pulse, and respiratory rate at presentation demonstrated poor ability to differentiate between MRSA and MSSA infection. CONCLUSIONS The results demonstrated no significant differences between MSSA and MRSA musculoskeletal infections for most hospital outcomes measured. However, MRSA infections required more operative interventions than MSSA infections. In addition, a predictive model based on severity markers obtained at presentation was unable to effectively differentiate between MRSA and MSSA infection. The clinical utility and capacity for early differentiation of MRSA and MSSA depends on virulence patterns that may vary temporally and geographically.
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Affiliation(s)
- Thomas J An
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | | | - Megan E Mignemi
- Vanderbilt University Medical Center, Departments of Orthopaedics
| | - Jeffrey Martus
- Vanderbilt University Medical Center, Departments of Orthopaedics
| | - James B Wood
- Pediatrics, Nashville, Tennessee
- Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Isaac P Thomsen
- Vanderbilt University School of Medicine, Nashville, Tennessee
- Pediatrics, Nashville, Tennessee
- Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jonathan G Schoenecker
- Vanderbilt University Medical Center, Departments of Orthopaedics
- Pediatrics, Nashville, Tennessee
- Vanderbilt University Medical Center, Departments of Pharmacology
- Pathology, Nashville, Tennessee
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The Clostridium difficile quorum-sensing molecule alters the Staphylococcus aureus toxin expression profile. Int J Antimicrob Agents 2017; 49:391-393. [PMID: 28111286 DOI: 10.1016/j.ijantimicag.2017.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/31/2016] [Accepted: 01/14/2017] [Indexed: 11/23/2022]
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Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria. Antibiotics (Basel) 2016; 5:antibiotics5040039. [PMID: 27983678 PMCID: PMC5187520 DOI: 10.3390/antibiotics5040039] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/23/2016] [Accepted: 12/06/2016] [Indexed: 11/17/2022] Open
Abstract
Sulfate-reducing bacteria (SRB) are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS) in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach.
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Woo SG, Lee SY, Lee SM, Lim KH, Ha EJ, Eom YB. Activity of novel inhibitors of Staphylococcus aureus biofilms. Folia Microbiol (Praha) 2016; 62:157-167. [PMID: 27864779 DOI: 10.1007/s12223-016-0485-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 11/13/2016] [Indexed: 12/27/2022]
Abstract
Staphylococcus aureus is one of the most important pathogens causing chronic biofilm infections. These are becoming more difficult to treat owing to drug resistance, particularly because S. aureus biofilms limit the efficacy of antimicrobial agents, leading to high morbidity and mortality. In the present study, we screened for inhibitors of S. aureus biofilm formation using a natural product library from the Korea Chemical Bank (KCB). Screening by crystal violet-based biomass staining assay identified hit compounds. Further examination of antibiofilm properties of these compounds was conducted and led to the identification of celastrol and telithromycin. In vitro, both celastrol and telithromycin were toxic to planktonic S. aureus and also active against a clinical methicillin-resistant S. aureus (MRSA) isolate. The effect of the compounds on preformed biofilms of clinical MRSA isolates was evaluated by confocal laser scanning microscopy (CLSM), which revealed the absence of typical biofilm architecture. In addition, celastrol and telithromycin inhibited the production of extracellular protein at selected sub-MIC concentrations, which revealed the reduced extracellular polymeric substance (EPS) secretion. Celastrol exhibited greater cytotoxicity than telithromycin. These data suggest that the hit compounds, especially telithromycin, could be considered novel inhibitors of S. aureus biofilm. Although the mechanisms of the effects on S. aureus biofilms are not fully understood, our data suggest that telithromycin could be a useful adjuvant therapeutic agent for S. aureus biofilm-related infections.
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Affiliation(s)
- Seung-Gyun Woo
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - So-Yeon Lee
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - So-Min Lee
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - Kyoung-Hee Lim
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - Eun-Ju Ha
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea
| | - Yong-Bin Eom
- Department of Medical Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea.
- Department of Biomedical Laboratory Science, College of Medical Sciences, Soonchunhyang University, 22 Soonchunhyang-ro, Shinchang-myeon, Asan-si, Chungcheongnam-do, 31538, Republic of Korea.
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Oyama K, Kawada-Matsuo M, Oogai Y, Hayashi T, Nakamura N, Komatsuzawa H. Antibacterial Effects of Glycyrrhetinic Acid and Its Derivatives on Staphylococcus aureus. PLoS One 2016; 11:e0165831. [PMID: 27820854 PMCID: PMC5098735 DOI: 10.1371/journal.pone.0165831] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/18/2016] [Indexed: 01/16/2023] Open
Abstract
Staphylococcus aureus is a major pathogen in humans and causes serious problems due to antibiotic resistance. We investigated the antimicrobial effect of glycyrrhetinic acid (GRA) and its derivatives against 50 clinical S. aureus strains, including 18 methicillin-resistant strains. The minimum inhibitory concentrations (MICs) of GRA, dipotassium glycyrrhizate, disodium succinoyl glycyrrhetinate (GR-SU), stearyl glycyrrhetinate and glycyrrhetinyl stearate were evaluated against various S. aureus strains. Additionally, we investigated the bactericidal effects of GRA and GR-SU against two specific S. aureus strains. DNA microarray analysis was also performed to clarify the mechanism underlying the antibacterial activity of GR-SU. We detected the antimicrobial activities of five agents against S. aureus strains. GRA and GR-SU showed strong antibacterial activities compared to the other three agents tested. At a higher concentration (above 2x MIC), GRA and GR-SU showed bactericidal activity, whereas at a concentration of 1x MIC, they showed a bacteriostatic effect. Additionally, GRA and GR-SU exhibited a synergistic effect with gentamicin. The expression of a large number of genes (including transporters) and metabolic factors (carbohydrates and amino acids) was altered by the addition of GR-SU, suggesting that the inhibition of these metabolic processes may influence the degree of the requirement for carbohydrates or amino acids. In fact, the requirement for carbohydrates or amino acids was increased in the presence of either GRA or GR-SU. GRA and GR-SU exhibited strong antibacterial activity against several S. aureus strains, including MRSA. This activity may be partly due to the inhibition of several pathways involved in carbohydrate and amino acid metabolism.
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Affiliation(s)
- Kentaro Oyama
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- Department of Oral maxillofacial Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Miki Kawada-Matsuo
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Norifumi Nakamura
- Department of Oral maxillofacial Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hitoshi Komatsuzawa
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
- * E-mail:
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Tiong HK, Hartson SD, Muriana PM. Comparison of Surface Proteomes of Adherence Variants of Listeria Monocytogenes Using LC-MS/MS for Identification of Potential Surface Adhesins. Pathogens 2016; 5:E40. [PMID: 27196934 PMCID: PMC4931391 DOI: 10.3390/pathogens5020040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/19/2016] [Accepted: 05/11/2016] [Indexed: 12/19/2022] Open
Abstract
The ability of Listeria monocytogenes to adhere and form biofilms leads to persistence in food processing plants and food-associated listeriosis. The role of specific surface proteins as adhesins to attach Listeria cells to various contact surfaces has not been well characterized to date. In prior research comparing different methods for surface protein extraction, the Ghost urea method revealed cleaner protein content as verified by the least cytoplasmic protein detected in surface extracts using LC-MS/MS. The same technique was utilized to extract and detect surface proteins among two surface-adherent phenotypic strains of L. monocytogenes (i.e., strongly and weakly adherent). Of 640 total proteins detected among planktonic and sessile cells, 21 protein members were exclusively detected in the sessile cells. Relative LC-MS/MS detection and quantification of surface-extracted proteins from the planktonic weakly adherent (CW35) and strongly adherent strains (99-38) were examined by protein mass normalization of proteins. We found that L. monocytogenes 99-38 exhibited a total of 22 surface proteins that were over-expressed: 11 proteins were detected in surface extracts of both sessile and planktonic 99-38 that were ≥5-fold over-expressed while another 11 proteins were detected only in planktonic 99-38 cells that were ≥10-fold over-expressed. Our results suggest that these protein members are worthy of further investigation for their involvement as surface adhesins.
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Affiliation(s)
- Hung King Tiong
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
- Robert M. Kerr Food & Agricultural Products Centre, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Steven D Hartson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Peter M Muriana
- Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.
- Robert M. Kerr Food & Agricultural Products Centre, Oklahoma State University, Stillwater, OK 74078, USA.
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Kavanaugh JS, Horswill AR. Impact of Environmental Cues on Staphylococcal Quorum Sensing and Biofilm Development. J Biol Chem 2016; 291:12556-12564. [PMID: 27129223 DOI: 10.1074/jbc.r116.722710] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Staphylococci are commensal bacteria that colonize the epithelial surfaces of humans and many other mammals. These bacteria can also attach to implanted medical devices and develop surface-associated biofilm communities that resist clearance by host defenses and available chemotherapies. These communities are often associated with persistent staphylococcal infections that place a tremendous burden on the healthcare system. Understanding the regulatory program that controls staphylococcal biofilm development, as well as the environmental conditions that modulate this program, has been a focal point of research in recent years. A central regulator controlling biofilm development is a peptide quorum-sensing system, also called the accessory gene regulator or agr system. In the opportunistic pathogen Staphylococcus aureus, the agr system controls production of exo-toxins and exo-enzymes essential for causing infections, and simultaneously, it modulates the ability of this pathogen to attach to surfaces and develop a biofilm, or to disperse from the biofilm state. In this review, we explore advances on the interconnections between the agr quorum-sensing system and biofilm mechanisms, and topics covered include recent findings on how different environmental conditions influence quorum sensing, the impact on biofilm development, and ongoing questions and challenges in the field. As our understanding of the quorum sensing and biofilm interconnection advances, there are growing opportunities to take advantage of this knowledge and develop therapeutic approaches to control staphylococcal infections.
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Affiliation(s)
- Jeffrey S Kavanaugh
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Alexander R Horswill
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242.
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Lather P, Mohanty AK, Jha P, Garsa AK. Contribution of Cell Surface Hydrophobicity in the Resistance of Staphylococcus aureus against Antimicrobial Agents. Biochem Res Int 2016; 2016:1091290. [PMID: 26966577 PMCID: PMC4761388 DOI: 10.1155/2016/1091290] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/19/2015] [Accepted: 01/11/2016] [Indexed: 11/18/2022] Open
Abstract
Staphylococcus aureus is found in a wide variety of habitats, including human skin, where many strains are commensals that may be clinically significant or contaminants of food. To determine the physiological characteristics of resistant strain of Staphylococcus aureus against pediocin, a class IIa bacteriocin, a resistant strain was compared with wild type in order to investigate the contribution of hydrophobicity to this resistance. Additional clumping of resistant strain relative to wild type in light microscopy was considered as an elementary evidence of resistance attainment. A delay in log phase attainment was observed in resistant strain compared to the wild type strain. A significant increase in cell surface hydrophobicity was detected for resistant strain in both hexadecane and xylene indicating the contribution of cell surface hydrophobicity as adaptive reaction against antimicrobial agents.
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Affiliation(s)
- Puja Lather
- Animal Biochemistry Division, National Dairy Research Institute, Karnal, Haryana 132001, India
| | - A. K. Mohanty
- Animal Biotechnology Division, National Dairy Research Institute, Karnal, Haryana 132001, India
| | - Pankaj Jha
- Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal, Haryana 132001, India
| | - Anita Kumari Garsa
- Animal Biochemistry Division, National Dairy Research Institute, Karnal, Haryana 132001, India
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77
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Mohsenzadeh M, Ghazvini K, Azimian A. Frequency of specific agr groups and antibiotic resistance in Staphylococcus aureus isolated from bovine mastitis in the northeast of Iran. VETERINARY RESEARCH FORUM : AN INTERNATIONAL QUARTERLY JOURNAL 2015; 6:295-9. [PMID: 26973764 PMCID: PMC4769334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 02/09/2015] [Indexed: 11/01/2022]
Abstract
Staphylococcus aureus is generally regarded as a leading cause of mastitis in dairy cattle. The aim of this study was to investigate the pattern of agr groups and any possible relationship between agr groups and antibiotic resistance among S. aureus strains isolated from bovine mastitis in Northeast of Iran. For this purpose, a total of 300 bovine mastitic milk samples were taken from dairy industry farms of Khorasan Razavi Province, Iran. S. aureus were isolated and identified according to the standard methods. Antibiotic susceptibility testing was conducted by disk diffusion method. In this study a total of 31 isolates of S. aureus were evaluated for agrD gene polymorphism by specific primers. Most of the isolates belonged to agr group I (54.8%), followed by agr group III (25.8%) and agr group II (19.4%). There was not any isolates belonging to group IV. Resistance to methicillin in agr group I isolates was more than other groups. Agr groups II and III were quite susceptible to methicillin. Due to high prevalent of S. aureus isolates and high antibiotic resistance rate in bovine mastitic isolates, it is important to verify the characteristics of S. aureus strains in Iran.
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Affiliation(s)
- Mohammad Mohsenzadeh
- Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran; ,Correspondence: Mohammad Mohsenzadeh. DVM, PhD ,Department of Food Hygiene and Aquaculture, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran. E-mail:
| | - Kiarash Ghazvini
- Antimicrobial Resistance Research Center, Avicenna Research Institute, Tehran, Iran;,Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran;
| | - Amir Azimian
- Department of Pathobiology, School of Medicine, North Khorasan University of Medical Sciences, Boujnord, Iran.
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Lysostaphin-coated titan-implants preventing localized osteitis by Staphylococcus aureus in a mouse model. PLoS One 2014; 9:e115940. [PMID: 25536060 PMCID: PMC4275259 DOI: 10.1371/journal.pone.0115940] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/02/2014] [Indexed: 12/11/2022] Open
Abstract
The increasing incidence of implant-associated infections induced by Staphylococcus aureus (SA) in combination with growing resistance to conventional antibiotics requires novel therapeutic strategies. In the current study we present the first application of the biofilm-penetrating antimicrobial peptide lysostaphin in the context of bone infections. In a standardized implant-associated bone infection model in mice beta-irradiated lysostaphin-coated titanium plates were compared with uncoated plates. Coating of the implant was established with a poly(D,L)-lactide matrix (PDLLA) comprising lysostaphin formulated in a stabilizing and protecting solution (SPS). All mice were osteotomized and infected with a defined count of SA. Fractures were fixed with lysostaphin-coated locking plates. Plates uncoated or PDLLA-coated served as controls. All mice underwent debridement and lavage on Days 7, 14, 28 to determine the bacterial load and local immune reaction. Fracture healing was quantified by conventional radiography. On Day 7 bacterial growth in the lavages of mice with lysostaphin-coated plates showed a significantly lower count to the control groups. Moreover, in the lysostaphin-coated plate groups complete fracture healing were observed on Day 28. The fracture consolidation was accompanied by a diminished local immune reaction. However, control groups developed an osteitis with lysis or destruction of the bone and an evident local immune response. The presented approach of terminally sterilized lysostaphin-coated implants appears to be a promising therapeutic approach for low grade infection or as prophylactic strategy in high risk fracture care e.g. after severe open fractures.
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79
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Contribution of Lactococcus lactis reducing properties to the downregulation of a major virulence regulator in Staphylococcus aureus, the agr system. Appl Environ Microbiol 2014; 80:7028-35. [PMID: 25192992 DOI: 10.1128/aem.02287-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is a major cause of food poisoning outbreaks associated with dairy products, because of the ingestion of preformed enterotoxins. The biocontrol of S. aureus using lactic acid bacteria (LAB) offers a promising opportunity to fight this pathogen while respecting the product ecosystem. We had previously established the ability of Lactococcus lactis, a lactic acid bacterium widely used in the dairy industry, to downregulate a major staphylococcal virulence regulator, the accessory gene regulator (agr) system, and, as a consequence, agr-controlled enterotoxins. In the present paper, we have shown that the oxygen-independent reducing properties of L. lactis contribute to agr downregulation. Neutralizing lactococcal reduction by adding potassium ferricyanide or maintaining the oxygen pressure constant at 50% released agr downregulation in the presence of L. lactis. This downregulation still occurred in an S. aureus srrA mutant, indicating that the staphylococcal respiratory response regulator SrrAB was not the only component in the signaling pathway. Therefore, this study clearly demonstrates the ability of L. lactis reducing properties to interfere with the expression of S. aureus virulence, thus highlighting this general property of LAB as a lever to control the virulence expression of this major pathogen in a food context and beyond.
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80
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Proctor RA, Kriegeskorte A, Kahl BC, Becker K, Löffler B, Peters G. Staphylococcus aureus Small Colony Variants (SCVs): a road map for the metabolic pathways involved in persistent infections. Front Cell Infect Microbiol 2014; 4:99. [PMID: 25120957 PMCID: PMC4112797 DOI: 10.3389/fcimb.2014.00099] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 07/07/2014] [Indexed: 12/31/2022] Open
Abstract
Persistent and relapsing infections, despite apparently adequate antibiotic therapy, occur frequently with many pathogens, but it is an especially prominent problem with Staphylococcus aureus infections. For the purposes of this review, persistence will encompass both of the concepts of long term survival within the host, including colonization, and the concept of resisting antibiotic therapy even when susceptible in the clinical microbiology laboratory. Over the past two decades, the mechanisms whereby bacteria achieve persistence are slowly being unraveled. S. aureus small colony variants (SCVs) are linked to chronic, recurrent, and antibiotic-resistant infections, and the study of SCVs has contributed significantly to understanding of persistence. In our earlier work, defects in electron transport and thymidylate biosynthesis were linked to the development of the SCV phenotype (reviewed in 2006), thus this work will be discussed only briefly. Since 2006, it has been found that persistent organisms including SCVs are part of the normal life cycle of bacteria, and often they arise in response to harsh conditions, e.g., antibiotics, starvation, host cationic peptides. Many of the changes found in these early SCVs have provided a map for the discovery mechanisms (pathways) for the development of persistent organisms. For example, changes in RNA processing, stringent response, toxin-antitoxin, ribosome protein L6 (RplF), and cold shock protein B (CspB) found in SCVs are also found in other persisters. In addition, many classic persister organisms also show slow growth, hence SCVs. Recent work on S. aureus USA300 has elucidated the impact of aerobic expression of arginine deiminase genes on its ability to chronically colonize the skin and survive in abscesses. S. aureus SCVs also express arginine deiminase genes aerobically as well. Thus, many pathways found activated in electron transport type of SCVs are also increased in persisters that have intact electron transport. Many of these changes in metabolism result in slow growth; hence, small colonies are formed. Another common theme is that slow growth is also associated with reduced expression of virulence factors and enhanced uptake/survival within host cells. These adaptations to survive within the host are rooted in responses that were required for organisms to survive in a harsh environment long before they were mammals on the earth.
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Affiliation(s)
- Richard A Proctor
- Departments of Medical Microbiology/Immunology and Medicine, University of Wisconsin School of Medicine and Public Health Madison, WI, USA
| | - André Kriegeskorte
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Barbara C Kahl
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Bettina Löffler
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital, Münster Münster, Germany
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81
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Diep BA, Equils O, Huang DB, Gladue R. Linezolid effects on bacterial toxin production and host immune response: review of the evidence. Curr Ther Res Clin Exp 2014; 73:86-102. [PMID: 24648596 DOI: 10.1016/j.curtheres.2012.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2012] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Linezolid is active against a broad range of gram-positive pathogens and has the potential to also affect production of bacterial toxins and host immune function. OBJECTIVE To assess the evidence for direct effects of linezolid on bacterial toxin synthesis and modulation of host immune responses. METHODS Literature searches were performed of the PubMed and OVID databases. Reviews and non-English language articles were excluded. Articles with information on the effect of linezolid on bacterial toxin synthesis and immune responses were selected for further review, and data were summarized. RESULTS Substantial in vitro evidence supports effects of linezolid on bacterial toxin production; however, the strength of the evidence and the nature of the effects are mixed. In the case of Staphylococcus aureus, repeated observations support the inhibition of production of certain staphylococcal toxins (Panton-Valentine leukocidin, protein A, and α- and β-hemolysin) by linezolid, whereas only solitary reports indicate inhibition (toxic shock syndrome toxin-1, coagulase, autolysins, and enterotoxins A and B) or stimulation (phenol-soluble modulins) of toxin production by linezolid. In the case of Streptococcus pyogenes, there are solitary reports of linezolid inhibition (protein M, deoxyribonuclease, and streptococcal pyrogenic exotoxins A, B, and F) or stimulation (immunogenic secreted protein 2 and streptococcal inhibitor of complement-mediated lysis) of toxin production, whereas published evidence for effects on streptolysin O production is conflicting. In vitro data are limited, but suggest that linezolid might also have indirect effects on host cytokine expression through inhibition of bacterial production of toxins. In vivo data from preclinical animal studies and a single clinical study in humans are limited and equivocal insofar as a potential role for linezolid in modulating the host inflammatory response; this is due in part to the difficulty in isolating antimicrobial effects and toxin synthesis inhibitory effects of linezolid from any secondary effects on host inflammatory response. CONCLUSIONS Available evidence supports the possibility that linezolid can inhibit, and in some cases stimulate, toxin production in clinically relevant pathogens. However, more research will be needed to determine the potential clinical relevance of those findings for linezolid.
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Affiliation(s)
- Binh An Diep
- Department of Medicine, University of California at San Francisco, San Francisco, California
| | - Ozlem Equils
- Medical Division, Pfizer Inc, Collegeville, Pennsylvania
| | - David B Huang
- Medical Division, Pfizer Inc, Collegeville, Pennsylvania
| | - Ron Gladue
- Pfizer Global Biotherapeutic Technologies, Cambridge, Massachusetts
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82
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Goh SY, Tan WS, Khan SA, Chew HP, Abu Kasim NH, Yin WF, Chan KG. Unusual multiple production of N-acylhomoserine lactones a by Burkholderia sp. strain C10B isolated from dentine caries. SENSORS 2014; 14:8940-9. [PMID: 24854358 PMCID: PMC4063041 DOI: 10.3390/s140508940] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 05/04/2014] [Accepted: 05/13/2014] [Indexed: 01/12/2023]
Abstract
Bacteria realize the ability to communicate by production of quorum sensing (QS) molecules called autoinducers, which regulate the physiological activities in their ecological niches. The oral cavity could be a potential area for the presence of QS bacteria. In this study, we report the isolation of a QS bacterial isolate C10B from dentine caries. Preliminary screening using Chromobacterium violaceum CV026 biosensor showed that isolate C10B was able to produce N-acylhomoserine lactones (AHLs). This bacterium was further identified as a member of Burkholderia, an opportunistic pathogen. The isolated Burkholderia sp. was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL), N-octanoyl-L-homoserine lactone (C8-HSL), N-decanoyl-L-homoserine lactone (C10-HSL) and N-dodecanoyl-L-homoserine lactone (C12-HSL).
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Affiliation(s)
- Share Yuan Goh
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Wen-Si Tan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Saad Ahmed Khan
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Hooi Pin Chew
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Noor Hayaty Abu Kasim
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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83
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Lade H, Paul D, Kweon JH. Quorum quenching mediated approaches for control of membrane biofouling. Int J Biol Sci 2014; 10:550-65. [PMID: 24910534 PMCID: PMC4046882 DOI: 10.7150/ijbs.9028] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 04/29/2014] [Indexed: 12/24/2022] Open
Abstract
Membrane biofouling is widely acknowledged as the most frequent adverse event in wastewater treatment systems resulting in significant loss of treatment efficiency and economy. Different strategies including physical cleaning and use of antimicrobial chemicals or antibiotics have been tried for reducing membrane biofouling. Such traditional practices are aimed to eradicate biofilms or kill the bacteria involved, but the greater efficacy in membrane performance would be achieved by inhibiting biofouling without interfering with bacterial growth. As a result, the search for environmental friendly non-antibiotic antifouling strategies has received much greater attention among scientific community. The use of quorum quenching natural compounds and enzymes will be a potential approach for control of membrane biofouling. This approach has previously proven useful in diseases and membrane biofouling control by triggering the expression of desired phenotypes. In view of this, the present review is provided to give the updated information on quorum quenching compounds and elucidate the significance of quorum sensing inhibition in control of membrane biofouling.
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Affiliation(s)
| | - Diby Paul
- Department of Environmental Engineering, Konkuk University, Seoul-143-701, Korea
| | - Ji Hyang Kweon
- Department of Environmental Engineering, Konkuk University, Seoul-143-701, Korea
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84
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Detection and measurement of staphylococcal enterotoxin-like K (SEl-K) secretion by Staphylococcus aureus clinical isolates. J Clin Microbiol 2014; 52:2536-43. [PMID: 24808237 DOI: 10.1128/jcm.00387-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Staphylococcal enterotoxin-like K (SEl-K) is a potent mitogen that elicits T-cell proliferation and cytokine production at very low concentrations. However, unlike the classical enterotoxins SEB and toxic shock syndrome toxin 1 (TSST-1), the gene for SEl-K is commonly present in more than half of all Staphylococcus aureus clinical isolates and is present in almost all USA300 community-acquired methicillin-resistant S. aureus (CA-MRSA) isolates. Sequencing of the sel-k gene in over 20 clinical isolates and comparative analysis with all 14 published sel-k sequences indicate that there are at least 6 variants of the sel-k gene, including one that is conserved among all examined USA300 strains. Additionally, we have developed a highly sensitive enzyme-linked immunosorbent assay (ELISA) that specifically detects and measures SEl-K protein in culture supernatants and biological fluids. Quantification of in vitro SEl-K secretion by various S. aureus isolates using this novel capture ELISA revealed detectable amounts of SEl-K secretion by all isolates, with the highest secretion levels being exhibited by MRSA strains that coexpress SEB. In vivo secretion was measured in a murine thigh abscess model, where similar levels of SEl-K accumulation were noted regardless of whether the infecting strain exhibited high or low secretion of SEl-K in vitro. We conclude that SEl-K is commonly expressed in the setting of staphylococcal infection, in significant amounts. SEl-K should be further explored as a target for passive immunotherapy against complicated S. aureus infection.
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85
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Laabei M, Jamieson WD, Massey RC, Jenkins ATA. Staphylococcus aureus interaction with phospholipid vesicles--a new method to accurately determine accessory gene regulator (agr) activity. PLoS One 2014; 9:e87270. [PMID: 24498061 PMCID: PMC3907525 DOI: 10.1371/journal.pone.0087270] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 12/27/2013] [Indexed: 11/19/2022] Open
Abstract
The staphylococcal accessory gene regulatory (agr) operon is a well-characterised global regulatory element that is important in the control of virulence gene expression for Staphylococcus aureus, a major human pathogen. Hence, accurate and sensitive measurement of Agr activity is central in understanding the virulence potential of Staphylococcus aureus, especially in the context of Agr dysfunction, which has been linked with persistent bacteraemia and reduced susceptibility to glycopeptide antibiotics. Agr function is typically measured using a synergistic haemolysis CAMP assay, which is believe to report on the level of expression of one of the translated products of the agr locus, delta toxin. In this study we develop a vesicle lysis test (VLT) that is specific to small amphipathic peptides, most notably delta and Phenol Soluble Modulin (PSM) toxins. To determine the accuracy of this VLT method in assaying Agr activity, we compared it to the CAMP assay using 89 clinical Staphylococcus aureus isolates. Of the 89 isolates, 16 were designated as having dysfunctional Agr systems by the CAMP assay, whereas only three were designated as such by VLT. Molecular analysis demonstrated that of these 16 isolates, the 13 designated as having a functional Agr system by VLT transcribed rnaIII and secreted delta toxin, demonstrating they have a functional Agr system despite the results of the CAMP assay. The agr locus of all 16 isolates was sequenced, and only the 3 designated as having a dysfunctional Agr system contained mutations, explaining their Agr dysfunction. Given the potentially important link between Agr dysfunction and clinical outcome, we have developed an assay that determines this more accurately than the conventional CAMP assay.
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Affiliation(s)
- Maisem Laabei
- Department of Chemistry, University of Bath, Claverton Down, Bath, United Kingdom
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - W. David Jamieson
- Department of Chemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Ruth C. Massey
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - A. Tobias A. Jenkins
- Department of Chemistry, University of Bath, Claverton Down, Bath, United Kingdom
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86
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Abstract
SUMMARY This review begins with a discussion of the large family of Staphylococcus aureus and beta-hemolytic streptococcal pyrogenic toxin T lymphocyte superantigens from structural and immunobiological perspectives. With this as background, the review then discusses the major known and possible human disease associations with superantigens, including associations with toxic shock syndromes, atopic dermatitis, pneumonia, infective endocarditis, and autoimmune sequelae to streptococcal illnesses. Finally, the review addresses current and possible novel strategies to prevent superantigen production and passive and active immunization strategies.
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87
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Gray B, Hall P, Gresham H. Targeting agr- and agr-Like quorum sensing systems for development of common therapeutics to treat multiple gram-positive bacterial infections. SENSORS 2013; 13:5130-66. [PMID: 23598501 PMCID: PMC3673130 DOI: 10.3390/s130405130] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/06/2013] [Accepted: 04/12/2013] [Indexed: 12/13/2022]
Abstract
Invasive infection by the Gram-positive pathogen Staphylococcus aureus is controlled by a four gene operon, agr that encodes a quorum sensing system for the regulation of virulence. While agr has been well studied in S. aureus, the contribution of agr homologues and analogues in other Gram-positive pathogens is just beginning to be understood. Intriguingly, other significant human pathogens, including Clostridium perfringens, Listeria monocytogenes, and Enterococcus faecalis contain agr or analogues linked to virulence. Moreover, other significant human Gram-positive pathogens use peptide based quorum sensing systems to establish or maintain infection. The potential for commonality in aspects of these signaling systems across different species raises the prospect of identifying therapeutics that could target multiple pathogens. Here, we review the status of research into these agr homologues, analogues, and other peptide based quorum sensing systems in Gram-positive pathogens as well as the potential for identifying common pathways and signaling mechanisms for therapeutic discovery.
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Affiliation(s)
- Brian Gray
- Department of Pharmaceutical Sciences, College of Pharmacy/MRF 208, MSC09 5360, University of New Mexico, Albuquerque, NM 87131-0001, USA; E-Mail:
- Research Service, New Mexico Veterans Affairs Medical Center, Albuquerque, NM 87108, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-505-265-1711 (ext. 2841)
| | - Pamela Hall
- Department of Pharmaceutical Sciences, College of Pharmacy/MRF 208, MSC09 5360, University of New Mexico, Albuquerque, NM 87131-0001, USA; E-Mail:
- Research Service, New Mexico Veterans Affairs Medical Center, Albuquerque, NM 87108, USA
| | - Hattie Gresham
- Research Service, New Mexico Veterans Affairs Medical Center, Albuquerque, NM 87108, USA
- Department of Internal Medicine, Division of Infectious Diseases, University of New Mexico, Albuquerque, NM 87131, USA; E-Mail:
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88
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Gordon CP, Williams P, Chan WC. Attenuating Staphylococcus aureus virulence gene regulation: a medicinal chemistry perspective. J Med Chem 2013; 56:1389-404. [PMID: 23294220 PMCID: PMC3585718 DOI: 10.1021/jm3014635] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
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Virulence gene expression in Staphylococcus aureus is tightly regulated by intricate networks of transcriptional regulators
and two-component signal transduction systems. There is now an emerging
body of evidence to suggest that the blockade of S. aureus virulence gene expression significantly attenuates infection in
experimental models. In this Perspective, we will provide insights
into medicinal chemistry strategies for the development of chemical
reagents that have the capacity to inhibit staphylococcal virulence
expression. These reagents can be broadly grouped into four categories:
(1) competitive inhibitors of the accessory gene regulator (agr) quorum sensing system, (2) inhibitors of AgrA–DNA
interactions, (3) RNAIII transcription inhibitors, and (4) inhibitors
of the SarA family of transcriptional regulators. We discuss the potential
of specific examples of antivirulence agents for the management and
treatment of staphylococcal infections.
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Affiliation(s)
- Christopher P Gordon
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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89
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Distinct roles of phenol-soluble modulins in spreading of Staphylococcus aureus on wet surfaces. Appl Environ Microbiol 2012. [PMID: 23183971 DOI: 10.1128/aem.03157-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The human pathogen Staphylococcus aureus is renowned for the rapid colonization of contaminated wounds, medical implants, and food products. Nevertheless, little is known about the mechanisms that allow S. aureus to colonize the respective wet surfaces. The present studies were therefore aimed at identifying factors used by S. aureus cells to spread over wet surfaces, starting either from planktonic or biofilm-associated states. Through proteomics analyses we pinpoint phenol-soluble modulins (PSMs) as prime facilitators of the spreading process. To dissect the roles of the eight PSMs produced by S. aureus, these peptides were chemically synthesized and tested in spreading assays with different psm mutant strains. The results show that PSMα3 and PSMγ are the strongest facilitators of spreading both for planktonic cells and cells in catheter-associated biofilms. Compared to the six other PSMs of S. aureus, PSMα3 and PSMγ combine strong surfactant activities with a relatively low overall hydropathicity. Importantly, we show that PSM-mediated motility of S. aureus facilitates the rapid colonization of wet surfaces next to catheters and the colonization of fresh meat.
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90
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18β-Glycyrrhetinic acid inhibits methicillin-resistant Staphylococcus aureus survival and attenuates virulence gene expression. Antimicrob Agents Chemother 2012; 57:241-7. [PMID: 23114775 DOI: 10.1128/aac.01023-12] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) has become a major source of infection in hospitals and in the community. Increasing antibiotic resistance in S. aureus strains has created a need for alternative therapies to treat disease. A component of the licorice root Glycyrrhiza spp., 18β-glycyrrhetinic acid (GRA), has been shown to have antiviral, antitumor, and antibacterial activity. This investigation explores the in vitro and in vivo effects of GRA on MRSA pulsed-field gel electrophoresis (PFGE) type USA300. GRA exhibited bactericidal activity at concentrations exceeding 0.223 μM. Upon exposure of S. aureus to sublytic concentrations of GRA, we observed a reduction in expression of key virulence genes, including saeR and hla. In murine models of skin and soft tissue infection, topical GRA treatment significantly reduced skin lesion size and decreased the expression of saeR and hla genes. Our investigation demonstrates that at high concentrations GRA is bactericidal to MRSA and at sublethal doses it reduces virulence gene expression in S. aureus both in vitro and in vivo.
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91
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Azimian A, Najar-Pirayeh S, Mirab-Samiee S, Naderi M. Occurrence of methicillin resistant Staphylococcus aureus (MRSA) among clinical samples in tehran-iran and its correlation with polymorphism of specific accessory gene regulator (AGR) groups. Braz J Microbiol 2012; 43:779-85. [PMID: 24031890 PMCID: PMC3768844 DOI: 10.1590/s1517-83822012000200043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 11/09/2011] [Accepted: 01/16/2012] [Indexed: 11/22/2022] Open
Abstract
Methicillin-Resistant Staphylococcus aureus (MRSA) is responsible for an increasing number of serious hospital and community acquired infections. Virulence gene expression in Staphylococcus aureus is orchestrated by regulators such as the accessory gene regulator (agr). Staphylococcal strains are divided into four major agr groups (agrI-IV) on the basis of agrD and agrC polymorphisms. The purpose of this study was to define the prevalence of MRSA strains in appointed Tehran's hospitals and then to define and compare the proportion of agr I, II, III, IV polymorphisms between MRSA and Methicillin Sensitive Staphylococcus aureus (MSSA) strains. A total of 235 isolates were evaluated by conventional antibiotic susceptibility tests and PCR for agr and mecA genes. 112 strains were MRSA (47.5%) and the most prevalent agr specific group was agr I followed by agr III, agr II and agr IV, respectively. The prevalence of agr groups amongst MRSA and MSSA strains was not statistically significant (P≥0.05). This study suggests that agr I is not only the most prevalent agr type in MRSAs but also the most common one in Methicillin Sensitive Staphylococcus aureus (MSSA) strains in Iran.
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Affiliation(s)
- Amir Azimian
- Department of Medical Bacteriology, School of medical Science, Tarbiat Modares University , Tehran, P.O.BOX: 14115-331
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92
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Tan C, Phillip Smith R, Srimani JK, Riccione KA, Prasada S, Kuehn M, You L. The inoculum effect and band-pass bacterial response to periodic antibiotic treatment. Mol Syst Biol 2012; 8:617. [PMID: 23047527 PMCID: PMC3472685 DOI: 10.1038/msb.2012.49] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/29/2012] [Indexed: 12/25/2022] Open
Abstract
The inoculum effect (IE) refers to the decreasing efficacy of an antibiotic with increasing bacterial density. It represents a unique strategy of antibiotic tolerance and it can complicate design of effective antibiotic treatment of bacterial infections. To gain insight into this phenomenon, we have analyzed responses of a lab strain of Escherichia coli to antibiotics that target the ribosome. We show that the IE can be explained by bistable inhibition of bacterial growth. A critical requirement for this bistability is sufficiently fast degradation of ribosomes, which can result from antibiotic-induced heat-shock response. Furthermore, antibiotics that elicit the IE can lead to 'band-pass' response of bacterial growth to periodic antibiotic treatment: the treatment efficacy drastically diminishes at intermediate frequencies of treatment. Our proposed mechanism for the IE may be generally applicable to other bacterial species treated with antibiotics targeting the ribosomes.
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Affiliation(s)
- Cheemeng Tan
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Jaydeep K Srimani
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Sameer Prasada
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Meta Kuehn
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Lingchong You
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Institute for Genome Sciences and Policy, Duke University, Durham, NC, USA
- Center for Systems Biology, Duke University, Durham, NC, USA
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93
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Schelin J, Wallin-Carlquist N, Cohn MT, Lindqvist R, Barker GC, Rådström P. The formation of Staphylococcus aureus enterotoxin in food environments and advances in risk assessment. Virulence 2011; 2:580-92. [PMID: 22030860 PMCID: PMC3260550 DOI: 10.4161/viru.2.6.18122] [Citation(s) in RCA: 213] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/15/2011] [Accepted: 09/16/2011] [Indexed: 01/02/2023] Open
Abstract
The recent finding that the formation of staphylococcal enterotoxins in food is very different from that in cultures of pure Staphylococcus aureus sheds new light on, and brings into question, traditional microbial risk assessment methods based on planktonic liquid cultures. In fact, most bacteria in food appear to be associated with surfaces or tissues in various ways, and interaction with other bacteria through molecular signaling is prevalent. Nowadays it is well established that there are significant differences in the behavior of bacteria in the planktonic state and immobilized bacteria found in multicellular communities. Thus, in order to improve the production of high-quality, microbiologically safe food for human consumption, in situ data on enterotoxin formation in food environments are required to complement existing knowledge on the growth and survivability of S. aureus. This review focuses on enterotoxigenic S. aureus and describes recent findings related to enterotoxin formation in food environments, and ways in which risk assessment can take into account virulence behavior. An improved understanding of how environmental factors affect the expression of enterotoxins in foods will enable us to formulate new strategies for improved food safety.
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Affiliation(s)
- Jenny Schelin
- Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden.
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94
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Preparation of polyester-based metal-cross linked polymeric composites as novel materials resistant to bacterial adhesion and biofilm formation. Molecules 2011; 16:933-50. [PMID: 21258299 PMCID: PMC6259101 DOI: 10.3390/molecules16010933] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Revised: 12/25/2010] [Accepted: 01/17/2011] [Indexed: 01/27/2023] Open
Abstract
Bacterial biofilms constitute an extremely resistant form of bacterial colonization with dire health and economical implications. Towards achieving polymeric composites capable of resisting bacterial adhesion and biofilm formation, we prepared five 2,6-pyridinedicarboxylate-based polyesters employing five different diol monomers. The resulting polyesters were complexed with copper (II) or silver (I). The new polymers were characterized by proton and carbon nuclear magnetic resonance spectroscopy, inherent viscosity, infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The corresponding metal complexes were characterized by differential scanning calorimetry and infrared spectroscopy. The amounts of complexed copper and silver were determined by atomic absorption spectrophotometry. Finally, the resulting composites were tested for their antibacterial potential and were found to effectively resist bacterial attachment and growth.
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95
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Thoendel M, Kavanaugh JS, Flack CE, Horswill AR. Peptide signaling in the staphylococci. Chem Rev 2010; 111:117-51. [PMID: 21174435 DOI: 10.1021/cr100370n] [Citation(s) in RCA: 288] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Matthew Thoendel
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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96
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Abstract
The important human pathogen Staphylococcus aureus is known to spread on soft agar plates. Here, we show that colony spreading of S. aureus involves the agr quorum-sensing system. This finding can be related to the agr-dependent expression of biosurfactants, such as phenol-soluble modulins, suggesting a connection between spreading motility and virulence.
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97
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de Almeida Carlos L, da Silva Amaral KA, Curcino Vieira IJ, Mathias L, Braz-Filho R, Silva Samarão S, Vieira-da-Motta O. Rauvolfia grandiflora (apocynaceae) extract interferes with staphylococcal density, enterotoxin production and antimicrobial activity. Braz J Microbiol 2010; 41:612-20. [PMID: 24031536 PMCID: PMC3768640 DOI: 10.1590/s1517-83822010000300011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/04/2009] [Accepted: 03/16/2010] [Indexed: 01/01/2023] Open
Abstract
Staphylococci bacteria are involved in many human and animal infections and development of alternative antimicrobial drugs against pathogenic bacteria is of great interest to the pharmaceutical industry. This study investigated the in vitro effect of Rauvolfia grandiflora methanol extract (root bark fraction) (RGE) on the density of ATCC strains of Staphylococcus aureus and Staphylococcus epidermidis, and a clinical enterotoxin-producer, S. aureus bovine strain. The alkaloid, isoreserpiline, obtained from dichloromethane extract of R. grandiflora was ineffective against the strains tested. After incubation of staphylococci strains in the presence of 1.2 μg.mL(-1) RGE, a significant inhibition of cell growth was observed using both spectrophotometry and ELISA assays. Twelve drugs were evaluated for their antimicrobial effects on culture RGE-treated cells using the disk diffusion method. Penicillin resistant strains became sensitive to the drug after RGE treatment. Furthermore, enterotoxin production by RGE-treated S. aureus was evaluated using a standardized ELISA method. Although staphylococcal LSA 88 bovine strain cells remained viable after exposure to the extract, enterotoxin production was precluded in 20% after RGE treatment. Significant interference in staphylococci cell density, drug sensitivity and enterotoxin secretion was observed after treatment. The study highlights the necessity to find new methods of disease prevention and new antibiotic therapies against staphylococcal infections.
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Affiliation(s)
- Lanamar de Almeida Carlos
- Laboratório de Zootecnia e Nutrição Animal, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
- Laboratório de Tecnologia de Alimentos, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
| | | | - Ivo José Curcino Vieira
- Laboratório de Ciências Químicas, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
- Laboratório de Tecnologia de Alimentos, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
| | - Leda Mathias
- Laboratório de Ciências Químicas, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
| | - Raimundo Braz-Filho
- Laboratório de Ciências Químicas, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
| | - Solange Silva Samarão
- Laboratório de Fitotecnia e Fitossanidade, Instituto Superior de Tecnologia e Ciências Agrárias, Campos dos Goytacazes, RJ, Brasil
| | - Olney Vieira-da-Motta
- Laboratório de Sanidade Animal, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil
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98
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Burnside K, Lembo A, de los Reyes M, Iliuk A, BinhTran NT, Connelly JE, Lin WJ, Schmidt BZ, Richardson AR, Fang FC, Tao WA, Rajagopal L. Regulation of hemolysin expression and virulence of Staphylococcus aureus by a serine/threonine kinase and phosphatase. PLoS One 2010; 5:e11071. [PMID: 20552019 PMCID: PMC2884019 DOI: 10.1371/journal.pone.0011071] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 05/14/2010] [Indexed: 02/02/2023] Open
Abstract
Exotoxins, including the hemolysins known as the alpha (α) and beta (β) toxins, play an important role in the pathogenesis of Staphylococcus aureus infections. A random transposon library was screened for S. aureus mutants exhibiting altered hemolysin expression compared to wild type. Transposon insertions in 72 genes resulting in increased or decreased hemolysin expression were identified. Mutations inactivating a putative cyclic di-GMP synthetase and a serine/threonine phosphatase (Stp1) were found to reduce hemolysin expression, and mutations in genes encoding a two component regulator PhoR, LysR family transcriptional regulator, purine biosynthetic enzymes and a serine/threonine kinase (Stk1) increased expression. Transcription of the hla gene encoding α toxin was decreased in a Δstp1 mutant strain and increased in a Δstk1 strain. Microarray analysis of a Δstk1 mutant revealed increased transcription of additional exotoxins. A Δstp1 strain is severely attenuated for virulence in mice and elicits less inflammation and IL-6 production than the Δstk1 strain. In vivo phosphopeptide enrichment and mass spectrometric analysis revealed that threonine phosphorylated peptides corresponding to Stk1, DNA binding histone like protein (HU), serine-aspartate rich fibrinogen/bone sialoprotein binding protein (SdrE) and a hypothetical protein (NWMN_1123) were present in the wild type and not in the Δstk1 mutant. Collectively, these studies suggest that Stk1 mediated phosphorylation of HU, SrdE and NWMN_1123 affects S. aureus gene expression and virulence.
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Affiliation(s)
- Kellie Burnside
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Annalisa Lembo
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Melissa de los Reyes
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Anton Iliuk
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Nguyen-Thao BinhTran
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - James E. Connelly
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Wan-Jung Lin
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Byron Z. Schmidt
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Anthony R. Richardson
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Ferric C. Fang
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Weiguo Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
- * E-mail:
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99
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Lin Z, Kotler DP, Schlievert PM, Sordillo EM. Staphylococcal enterocolitis: forgotten but not gone? Dig Dis Sci 2010; 55:1200-7. [PMID: 19609675 DOI: 10.1007/s10620-009-0886-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 06/19/2009] [Indexed: 12/27/2022]
Abstract
PURPOSE Staphylococcus aureus may cause antibiotic-associated diarrhea and enterocolitis, with or without preceding antibiotic use, in immunocompromised adults or infants, or individuals with predisposing conditions, but there is little appreciation of this condition clinically. CLINICAL DISEASE: The main clinical feature that helps to differentiate staphylococcal enterocolitis (SEC) from Clostridium difficile-associated diarrhea is large-volume, cholera-like diarrhea in the former case. A predominance of gram-positive cocci in clusters on gram stain of stool or biopsy specimens and the isolation of S. aureus as the dominant or sole flora support the diagnosis. PATHOGENESIS The pathogenesis of SEC requires the interaction of staphylococcal enterotoxins, which function as superantigens, with interstitial epithelial lymphocytes and intestinal epithelial cells (IECs). MANAGEMENT Most SEC represents recent S. aureus acquisition, so that improved infection prevention practices can reduce disease recurrence. Management should include aggressive fluid management and repletion and oral vancomycin.
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Affiliation(s)
- Zheng Lin
- Division of Gastroenterology, Department of Medicine, St. Luke's-Roosevelt Hospital Center, New York, NY 10025, USA
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100
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Schlievert PM, Strandberg KL, Lin YC, Peterson ML, Leung DYM. Secreted virulence factor comparison between methicillin-resistant and methicillin-sensitive Staphylococcus aureus, and its relevance to atopic dermatitis. J Allergy Clin Immunol 2010; 125:39-49. [PMID: 20109735 DOI: 10.1016/j.jaci.2009.10.039] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/23/2009] [Accepted: 10/26/2009] [Indexed: 12/21/2022]
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains have emerged as serious health threats in the last 15 years. They are associated with large numbers of atopic dermatitis skin and soft tissue infections, but when they originate from skin and mucous membranes, have the capacity to produce sepsis and highly fatal pulmonary infections characterized as necrotizing pneumonia, purpura fulminans, and postviral toxic shock syndrome. This review is a discussion of the emergence of 3 major CA-MRSA organisms, designated CA-MRSA USA400, followed by USA300, and most recently USA200. CA-MRSA USA300 and USA400 isolates and their methicillin-sensitive counterparts (community-associated methicillin-sensitive S aureus) typically produce highly inflammatory cytolysins alpha-toxin, gamma-toxin, delta-toxin (as representative of the phenol soluble modulin family of cytolysins), and Panton Valentine leukocidin. USA300 isolates produce the superantigens enterotoxin-like Q and a highly pyrogenic deletion variant of toxic shock syndrome toxin 1 (TSST-1), whereas USA400 isolates produce the superantigens staphylococcal enterotoxin B or staphylococcal enterotoxin C. USA200 CA-MRSA isolates produce small amounts of cytolysins but produce high levels of TSST-1. In contrast, their methicillin-sensitive S aureus counterparts produce various cytolysins, apparently in part dependent on the niche occupied in the host and levels of TSST-1 expressed. Significant differences seen in production of secreted virulence factors by CA-MRSA versus hospital-associated methicillin-resistant S aureus and community-associated methicillin-sensitive S aureus strains appear to be a result of the need to specialize as the result of energy drains from both virulence factor production and methicillin resistance.
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Affiliation(s)
- Patrick M Schlievert
- Department of Microbiology, University of Minnesota Medical School, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
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