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Sykes EME, White D, McLaughlin S, Kumar A. Salicylic acids and pathogenic bacteria: new perspectives on an old compound. Can J Microbiol 2024; 70:1-14. [PMID: 37699258 DOI: 10.1139/cjm-2023-0123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Salicylic acids have been used in human and veterinary medicine for their anti-pyretic, anti-inflammatory, and analgesic properties for centuries. A key role of salicylic acid-immune modulation in response to microbial infection-was first recognized during studies of their botanical origin. The effects of salicylic acid on bacterial physiology are diverse. In many cases, they impose selective pressures leading to development of cross-resistance to antimicrobial compounds. Initial characterization of these interactions was in Escherichia coli, where salicylic acid activates the multiple antibiotic resistance (mar) operon, resulting in decreased antibiotic susceptibility. Studies suggest that stimulation of the mar phenotype presents similarly in closely related Enterobacteriaceae. Salicylic acids also affect virulence in many opportunistic pathogens by decreasing their ability to form biofilms and increasing persister cell populations. It is imperative to understand the effects of salicylic acid on bacteria of various origins to illuminate potential links between environmental microbes and their clinically relevant antimicrobial-resistant counterparts. This review provides an update on known effects of salicylic acid and key derivatives on a variety of bacterial pathogens, offers insights to possible potentiation of current treatment options, and highlights cellular regulatory networks that have been established during the study of this important class of medicines.
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Affiliation(s)
- Ellen M E Sykes
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Dawn White
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Sydney McLaughlin
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Ayush Kumar
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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Chan LC, Lee HK, Wang L, Chaili S, Xiong YQ, Bayer AS, Proctor RA, Yeaman MR. Diflunisal and Analogue Pharmacophores Mediating Suppression of Virulence Phenotypes in Staphylococcus aureus. Antibiotics (Basel) 2023; 12:1180. [PMID: 37508276 PMCID: PMC10376238 DOI: 10.3390/antibiotics12071180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 06/26/2023] [Accepted: 07/08/2023] [Indexed: 07/30/2023] Open
Abstract
Invasive methicillin-resistant Staphylococcus aureus (MRSA) infections are leading causes of morbidity and mortality that are complicated by increasing resistance to conventional antibiotics. Thus, minimizing virulence and enhancing antibiotic efficacy against MRSA is a public health imperative. We originally demonstrated that diflunisal (DIF; [2-hydroxy-5-(2,4-difluorophenyl) benzoic acid]) inhibits S. aureus virulence factor expression. To investigate pharmacophores that are active in this function, we evaluated a library of structural analogues for their efficacy to modulate virulence phenotypes in a panel of clinically relevant S. aureus isolates in vitro. Overall, the positions of the phenyl, hydroxyl, and carboxylic moieties and the presence or type of halogen (F vs. Cl) influenced the efficacy of compounds in suppressing hemolysis, proteolysis, and biofilm virulence phenotypes. Analogues lacking halogens inhibited proteolysis to an extent similar to DIF but were ineffective at reducing hemolysis or biofilm production. In contrast, most analogues lacking the hydroxyl or carboxylic acid groups did not suppress proteolysis but did mitigate hemolysis and biofilm production to an extent similar to DIF. Interestingly, chirality and the substitution of fluorine with chlorine resulted in a differential reduction in virulence phenotypes. Together, this pattern of data suggests virulence-suppressing pharmacophores of DIF and structural analogues integrate halogen, hydroxyl, and carboxylic acid moiety stereochemistry. The anti-virulence effects of DIF were achieved using concentrations that are safe in humans, do not impair platelet antimicrobial functions, do not affect S. aureus growth, and do not alter the efficacy of conventional antibiotics. These results offer proof of concept for using novel anti-virulence strategies as adjuvants to antibiotic therapy to address the challenge of MRSA infection.
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Affiliation(s)
- Liana C Chan
- Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90024, USA
- Institute for Infection and Immunity, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Hong K Lee
- Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Institute for Infection and Immunity, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Ling Wang
- Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Institute for Infection and Immunity, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Siyang Chaili
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, 2311 Pierce Ave., Nashville, TN 37232, USA
| | - Yan Q Xiong
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90024, USA
- Institute for Infection and Immunity, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Arnold S Bayer
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90024, USA
- Institute for Infection and Immunity, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Richard A Proctor
- Departments of Medical Microbiology & Immunology and Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Michael R Yeaman
- Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90024, USA
- Institute for Infection and Immunity, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
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Pant N, Rush C, Warner J, Eisen DP. Effect of Savirin or Ticagrelor Treatment on the Expression of Commonly Used Reference Genes in Staphylococcus aureus. Microorganisms 2023; 11:microorganisms11020336. [PMID: 36838300 PMCID: PMC9964243 DOI: 10.3390/microorganisms11020336] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/19/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Reference genes are frequently used for the normalization of quantitative reverse transcriptase PCR (qRTPCR) data in gene expression studies. Staphylococcus aureus is one of the most common causes of biofilm-related infections. Savirin and ticagrelor show in vitro as well as in vivo antibiofilm activity against S. aureus. The main aim of this study was to identify the most stably expressed reference genes to study the effect of these molecules on genes in a strong biofilm producing S. aureus isolate isolated from biofilm-related infection. Quantitative real-time PCR was performed by using relative quantification method. Four different algorithms, delta Ct, normfinder, bestkeeper, and genorm, followed by a comprehensive analysis was used to identify the most stable reference genes from a list of sixteen different candidate reference genes. All four algorithms reported different results, with some comparable findings among some methods. In the comprehensive analysis of the results of all the algorithms used, the most stable reference genes found were spa, rpoD, and pyk for savirin treatment experiment and gapdH, gyrA, and gmk for ticagrelor treatment experiment. The optimal number of reference genes required was two for both the experimental conditions. Despite having some drawbacks, each algorithm can reliably determine an appropriate reference gene independently. However, based on consensus ranking and the required optimal number of reference genes reported, spa and rpoD were the most appropriate reference genes for savirin treatment experiment, and gapdH and gyrA were most appropriate for ticagrelor treatment experiment. This study provides baseline data on reference genes to study the effect of savirin or ticagrelor treatment on the expression of potential reference genes in S. aureus. We recommend prior re-validation of reference genes on a case-by-case basis before they can be used.
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Affiliation(s)
- Narayan Pant
- College of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia
- Australian Institute of Tropical Health and Medicine, Townsville, QLD 4811, Australia
- Correspondence:
| | - Catherine Rush
- Australian Institute of Tropical Health and Medicine, Townsville, QLD 4811, Australia
| | - Jeffrey Warner
- Australian Institute of Tropical Health and Medicine, Townsville, QLD 4811, Australia
| | - Damon P. Eisen
- College of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia
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Regulation of Staphylococcal Capsule by SarZ is SigA-Dependent. J Bacteriol 2022; 204:e0015222. [PMID: 35862799 PMCID: PMC9380528 DOI: 10.1128/jb.00152-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Production of capsular polysaccharides in Staphylococcus aureus is transcriptionally regulated by a control region of the cap operon that consists of SigA- and SigB-dependent promoters. A large number of regulators have been shown to affect cap gene expression. However, regulation of capsule is only partially understood. Here we found that SarZ was another regulator that activated the cap genes through the SigA-dependent promoter. Gel electrophoresis mobility shift experiments revealed that SarZ is bound to a broad region of the cap promoter including the SigA-dependent promoter but mainly the downstream region. We demonstrated that activation of cap expression by SarZ was independent of MgrA, which also activated capsule through the SigA-dependent promoter. Our results further showed that oxidative stress with hydrogen peroxide (H2O2) treatments enhanced SarZ activation of cap expression, indicating that SarZ is able to sense oxidative stress to regulate capsule production. IMPORTANCE Expression of virulence genes in Staphylococcus aureus is affected by environmental cues and is regulated by a surprisingly large number of regulators. Much is still unknown about how virulence factors are regulated by environment cues at the molecular level. Capsule is an antiphagocytic virulence factor that is highly regulated. In this study, we found SarZ was an activator of capsule and that the regulation of capsule by SarZ was affected by oxidative stress. These results provide an example of how a virulence factor could be regulated in response to an environmental cue. As the host oxidative defense system plays an important role against S. aureus, this study contributes to a better understanding of virulence gene regulation and staphylococcal pathogenesis.
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Turner AB, Gerner E, Firdaus R, Echeverz M, Werthén M, Thomsen P, Almqvist S, Trobos M. Role of sodium salicylate in Staphylococcus aureus quorum sensing, virulence, biofilm formation and antimicrobial susceptibility. Front Microbiol 2022; 13:931839. [PMID: 35992652 PMCID: PMC9384861 DOI: 10.3389/fmicb.2022.931839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/06/2022] [Indexed: 01/01/2023] Open
Abstract
The widespread threat of antibiotic resistance requires new treatment options. Disrupting bacterial communication, quorum sensing (QS), has the potential to reduce pathogenesis by decreasing bacterial virulence. The aim of this study was to investigate the influence of sodium salicylate (NaSa) on Staphylococcus aureus QS, virulence production and biofilm formation. In S. aureus ATCC 25923 (agr III), with or without serum, NaSa (10 mM) downregulated the agr QS system and decreased the secretion levels of alpha-hemolysin, staphopain A and delta-hemolysin. Inhibition of agr expression caused a downregulation of delta-hemolysin, decreasing biofilm dispersal and increasing biofilm formation on polystyrene and titanium under static conditions. In contrast, NaSa did not increase biofilm biomass under flow but caused one log10 reduction in biofilm viability on polystyrene pegs, resulting in biofilms being twice as susceptible to rifampicin. A concentration-dependent effect of NaSa was further observed, where high concentrations (10 mM) decreased agr expression, while low concentrations (≤0.1 mM) increased agr expression. In S. aureus 8325-4 (agr I), a high concentration of NaSa (10 mM) decreased hla expression, and a low concentration of NaSa (≤1 mM) increased rnaIII and hla expression. The activity of NaSa on biofilm formation was dependent on agr type and material surface. Eight clinical strains isolated from prosthetic joint infection (PJI) or wound infection belonging to each of the four agr types were evaluated. The four PJI S. aureus strains did not change their biofilm phenotype with NaSa on the clinically relevant titanium surface. Half of the wound strains (agr III and IV) did not change the biofilm phenotype in the 3D collagen wound model. In addition, compared to the control, ATCC 25923 biofilms formed with 10 mM NaSa in the collagen model were more susceptible to silver. It is concluded that NaSa can inhibit QS in S. aureus, decreasing the levels of toxin production with certain modulation of biofilm formation. The effect on biofilm formation was dependent on the strain and material surface. It is suggested that the observed NaSa inhibition of bacterial communication is a potential alternative or adjuvant to traditional antibiotics.
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Affiliation(s)
- Adam Benedict Turner
- Department of Biomaterials, University of Gothenburg, The Sahlgrenska Academy, Gothenburg, Sweden
- Center for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Erik Gerner
- Department of Biomaterials, University of Gothenburg, The Sahlgrenska Academy, Gothenburg, Sweden
- Center for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
- Mölnlycke Health Care AB, Gothenburg, Sweden
| | - Rininta Firdaus
- Department of Biomaterials, University of Gothenburg, The Sahlgrenska Academy, Gothenburg, Sweden
- Center for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Maite Echeverz
- Microbial Pathogenesis Research Unit, Public University of Navarre, Pamplona, Spain
| | - Maria Werthén
- Department of Biomaterials, University of Gothenburg, The Sahlgrenska Academy, Gothenburg, Sweden
- Center for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
| | - Peter Thomsen
- Department of Biomaterials, University of Gothenburg, The Sahlgrenska Academy, Gothenburg, Sweden
| | | | - Margarita Trobos
- Department of Biomaterials, University of Gothenburg, The Sahlgrenska Academy, Gothenburg, Sweden
- Center for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
- *Correspondence: Margarita Trobos,
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Within-Host Adaptation of Staphylococcus aureus in a Bovine Mastitis Infection Is Associated with Increased Cytotoxicity. Int J Mol Sci 2021; 22:ijms22168840. [PMID: 34445550 PMCID: PMC8396210 DOI: 10.3390/ijms22168840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/04/2021] [Accepted: 08/10/2021] [Indexed: 11/17/2022] Open
Abstract
Within-host adaptation is a typical feature of chronic, persistent Staphylococcus aureus infections. Research projects addressing adaptive changes due to bacterial in-host evolution increase our understanding of the pathogen’s strategies to survive and persist for a long time in various hosts such as human and bovine. In this study, we investigated the adaptive processes of S. aureus during chronic, persistent bovine mastitis using a previously isolated isogenic strain pair from a dairy cow with chronic, subclinical mastitis, in which the last variant (host-adapted, Sigma factor SigB-deficient) quickly replaced the initial, dominant variant. The strain pair was cultivated under specific in vitro infection-relevant growth-limiting conditions (iron-depleted RPMI under oxygen limitation). We used a combinatory approach of surfaceomics, molecular spectroscopic fingerprinting and in vitro phenotypic assays. Cellular cytotoxicity assays using red blood cells and bovine mammary epithelial cells (MAC-T) revealed changes towards a more cytotoxic phenotype in the host-adapted isolate with an increased alpha-hemolysin (α-toxin) secretion, suggesting an improved capacity to penetrate and disseminate the udder tissue. Our results foster the hypothesis that within-host evolved SigB-deficiency favours extracellular persistence in S. aureus infections. Here, we provide new insights into one possible adaptive strategy employed by S. aureus during chronic, bovine mastitis, and we emphasise the need to analyse genotype–phenotype associations under different infection-relevant growth conditions.
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Dotto C, Lombarte Serrat A, Ledesma M, Vay C, Ehling-Schulz M, Sordelli DO, Grunert T, Buzzola F. Salicylic acid stabilizes Staphylococcus aureus biofilm by impairing the agr quorum-sensing system. Sci Rep 2021; 11:2953. [PMID: 33536503 PMCID: PMC7858585 DOI: 10.1038/s41598-021-82308-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 01/19/2021] [Indexed: 01/30/2023] Open
Abstract
Salicylic acid (SAL) has recently been shown to induce biofilm formation in Staphylococcus aureus and to affect the expression of virulence factors. This study was aimed to investigate the effect of SAL on the regulatory agr system and its impact on S. aureus biofilm formation. The agr quorum-sensing system, which is a central regulator in S. aureus pathogenicity, plays a pivotal role in the dispersal of S. aureus mature biofilms and contributes to the creation of new colonization sites. Here, we demonstrate that SAL impairs biofilm dispersal by interfering with agr expression. As revealed by our work, protease and surfactant molecule production is diminished, and bacterial cell autolysis is also negatively affected by SAL. Furthermore, as a consequence of SAL treatment, the S. aureus biofilm matrix revealed the lack of extracellular DNA. In silico docking and simulation of molecular dynamics provided evidence for a potential interaction of AgrA and SAL, resulting in reduced activity of the agr system. In conclusion, SAL stabilized the mature S. aureus biofilms, which may prevent bacterial cell dissemination. However, it may foster the establishment of infections locally and consequently increase bacterial persistence leading to therapeutic failure.
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Affiliation(s)
- Cristian Dotto
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), CONICET, Buenos Aires, Argentina
| | - Andrea Lombarte Serrat
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Martín Ledesma
- Instituto de Fisiopatología y Bioquímica Clínica (INFIBIOC), Facultad de Farmacia y Bioquímica, Hospital de Clínicas José de San Martín, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Carlos Vay
- Instituto de Fisiopatología y Bioquímica Clínica (INFIBIOC), Facultad de Farmacia y Bioquímica, Hospital de Clínicas José de San Martín, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Daniel O Sordelli
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Tom Grunert
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Fernanda Buzzola
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina.
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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MgrA Activates Staphylococcal Capsule via SigA-Dependent Promoter. J Bacteriol 2020; 203:JB.00495-20. [PMID: 33077637 DOI: 10.1128/jb.00495-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/14/2020] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus capsule polysaccharide is an important antiphagocytic virulence factor. The cap genes are regulated at the promoter element (Pcap) upstream of the cap operon. Pcap, which consists of a dominant SigB-dependent promoter and a weaker upstream SigA-dependent promoter, is activated by global regulator MgrA. How MgrA activates capsule is unclear. Here, we showed that MgrA directly bound to the Pcap region and affected the SigA-dependent promoter. Interestingly, an electrophoretic mobility shift assay showed that MgrA bound to a large region of Pcap, mainly downstream of the SigA-dependent promoter. We further showed that the ArlRS two-component system and the Agr quorum sensing system activated capsule primarily through MgrA in the early growth phases.IMPORTANCE The virulence of Staphylococcus aureus depends on the expression of various virulence factors, which is governed by a complex regulatory network. We have been using capsule as a model virulence factor to study virulence gene regulation in S. aureus MgrA is one of the regulators of capsule and has a major effect on capsule production. However, how MgrA regulates capsule genes is not understood. In this study, we were able to define the mechanism involving MgrA regulation of capsule. In addition, we also delineated the role of MgrA in capsule regulatory pathways involving the key virulence regulators Agr and Arl. This study further advances our understanding of virulence gene regulation in S. aureus, an important human pathogen.
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Kongkham B, Prabakaran D, Puttaswamy H. Opportunities and challenges in managing antibiotic resistance in bacteria using plant secondary metabolites. Fitoterapia 2020; 147:104762. [PMID: 33069839 DOI: 10.1016/j.fitote.2020.104762] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 12/11/2022]
Abstract
Development of antibiotic resistance (ABR) in bacteria and its multidimensional spread is an emerging global threat that needs immediate attention. Extensive antibiotics (AB) usage results in development of ABR in bacteria by target modification, production of AB degrading enzymes, porin modifications, efflux pumps overexpression, etc. To counter this, apart from strict regulation of AB use and behavioural changes, research and development (R&D) of newer antimicrobials are in place. One such emerging approach to combat ABR is the use of structurally and functionally diverse plant secondary metabolites (PSMs) in combination with the conventional AB. Either the PSMs are themselves antimicrobial or they potentiate the activity of the AB through a range of mechanisms. However, their use is lagging due to poor knowledge of mode of action, structure-activity relationships, pharmacokinetics, etc. This review paper discussed the opportunities and challenges in managing ABR using PSMs. Mechanisms of ABR development in bacteria and current strategies to counter them were studied and the areas where PSMs can play an important role were highlighted. The use of PSMs, both as an anti-resistance and anti-virulence agent in combination therapy to counter multi-drug resistance along with their mechanisms of action, has been discussed in detail. The difficulties in the commercialisation of PSMs and strategies to overcome them along with future priority areas of research have also been given. Following the given R&D path will definitely help in better understanding and utilising the full potential of PSMs in solving the problem of antimicrobial resistance (AMR).
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Affiliation(s)
- Bhani Kongkham
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Duraivadivel Prabakaran
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India
| | - Hariprasad Puttaswamy
- Environmental Biotechnology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, Delhi 110016, India.
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Gerner E, Almqvist S, Werthén M, Trobos M. Sodium salicylate interferes with quorum-sensing-regulated virulence in chronic wound isolates of Pseudomonas aeruginosa in simulated wound fluid. J Med Microbiol 2020; 69:767-780. [PMID: 32320374 PMCID: PMC7451038 DOI: 10.1099/jmm.0.001188] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Introduction. An important factor for delayed healing of chronic wounds is the presence of bacteria. Quorum sensing (QS), a cell density-dependent signalling system, controls the production of many virulence factors and biofilm formation in Pseudomonas aeruginosa.Aim. Inhibition by sodium salicylate (NaSa) of QS-regulated virulence expression was evaluated in QS-characterized clinical wound isolates of P. aeruginosa, cultured in serum-containing medium.Methodology. Fourteen clinical P. aeruginosa strains from chronic wounds were evaluated for the production of QS signals and virulence factors. Inhibition of QS by NaSa in P. aeruginosa clinical strains, wild-type PAO1 and QS reporter strains was evaluated using in vitro assays for the production of biofilm, pyocyanin, siderophores, alkaline protease, elastase and stapholytic protease.Results. Six clinical strains secreted several QS-associated virulence factors and signal molecules and two were negative for all factors. Sub-inhibitory concentrations of NaSa downregulated the expression of the QS-related genes lasB, rhlA and pqsA and reduced the secretion of several virulence factors in PAO1 and clinical strains cultured in serum. Compared to serum-free media, the presence of serum increased the expression of QS genes and production of siderophores and pyocyanin but decreased biofilm formation.Conclusions. Pseudomonas aeruginosa from chronic wound infections showed different virulence properties. While very few strains showed no QS activity, approximately half were highly virulent and produced QS signals, suggesting that the targeting of QS is a viable and relevant strategy for infection control. NaSa showed activity as a QS-inhibitor by lowering the virulence phenotypes and QS signals at both transcriptional and extracellular levels.
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Affiliation(s)
- Erik Gerner
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Mölnlycke Health Care AB, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
| | | | - Maria Werthén
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden.,Department of Health Sciences, University West, Trollhättan, Sweden
| | - Margarita Trobos
- Department of Biomaterials, The Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.,Center for Antibiotic Resistance Research (CARe) at University of Gothenburg, Gothenburg, Sweden
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MgrA Negatively Impacts Staphylococcus aureus Invasion by Regulating Capsule and FnbA. Infect Immun 2019; 87:IAI.00590-19. [PMID: 31591167 DOI: 10.1128/iai.00590-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 09/27/2019] [Indexed: 01/19/2023] Open
Abstract
Virulence genes are regulated by a complex regulatory network in Staphylococcus aureus Some of the regulators are global in nature and affect many downstream genes. MgrA is a multiple-gene regulator that has been shown to activate genes involved in capsule biosynthesis and repress surface protein genes. The goal of this study was to demonstrate the biological significance of MgrA regulation of capsule and surface proteins. We found that strain Becker possessed one fibronectin-binding protein, FnbA, and that FnbA was the predominant protein involved in invasion of nonphagocytic HeLa cells. By genetic analysis of strains with different amounts of capsule, we demonstrated that capsule impeded invasion of HeLa cells by masking the bacterial cell wall-anchored protein FnbA. Using variants with different levels of mgrA transcription, we further demonstrated that MgrA negatively impacted invasion by activating the cap genes involved in capsule biosynthesis and repressing the fnbA gene. Thus, we conclude that MgrA negatively impacts cell invasion of S. aureus Becker by promoting capsule and repressing FnbA.
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Hannachi N, Habib G, Camoin-Jau L. Aspirin Effect on Staphylococcus aureus-Platelet Interactions During Infectious Endocarditis. Front Med (Lausanne) 2019; 6:217. [PMID: 31681776 PMCID: PMC6803506 DOI: 10.3389/fmed.2019.00217] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 09/23/2019] [Indexed: 12/29/2022] Open
Abstract
Infectious endocarditis (IE) is a rare disease associated with high mortality and morbidity rate. The platelet–bacterial interaction presents the cornerstone of the development of endocardial vegetation. The epidemiology of IE has undergone profound changes between the last and the new decade, with Staphylococcus aureus becoming the main incriminated species. Despite improvements in antibiotic and surgical therapies, embolic disorders remain highly associated with IE that can be fatal. Antiplatelet drugs have been widely proposed to overcome embolic events associated with IE. This proposal has been supported by numerous in vitro, experimental, and clinical studies. However, other studies have yielded conflicting results. In this review, we focus on the effect of aspirin on the genesis of S. aureus endocarditic vegetation, as well as on the management of embolic and hemorrhagic events related to it, starting by its influence on the platelet–bacteria interaction.
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Affiliation(s)
- Nadji Hannachi
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France
| | - Gilbert Habib
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France.,Département de Cardiologie, Hôpital de la Timone, AP-HM, Marseille, France
| | - Laurence Camoin-Jau
- Aix Marseille Univ, IRD, APHM, MEPHI, IHU Méditerranée Infection, Marseille, France.,Laboratoire d'Hématologie, Hôpital de la Timone, APHM, Marseille, France
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Lamure J, Chevalier M, Rathelot P, Mignolet F, Precheur I. In Vitro Screening of the Antibacterial and Anti-Candida Properties of Crushed Nonantimicrobial Drugs Frequently Prescribed in Nursing Homes. Res Gerontol Nurs 2018; 11:82-90. [PMID: 29451932 DOI: 10.3928/19404921-20180131-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 12/14/2017] [Indexed: 01/21/2023]
Abstract
Frail older adults often experience swallowing disorders, prompting nursing staff to crush tablets, open capsules, and mix drugs into their meals or gelled water. However, crushing drugs can lead to pharmacological and gustatory problems. As crushed drugs can stay in prolonged contact with oral microbial biofilm, the current study aimed to investigate their antimicrobial properties. Crushed drugs were diluted in 1 mL of isotonic water and assayed in vitro for: (a) growth inhibition of five bacterial strains and Candida albicans by the diffusion method; (b) inhibition of Streptococcus salivarius and C. albicans biofilm formation; and (c) elimination of a preformed biofilm of S. salivarius and C. albicans after 5-minute contact. Eight of 29 crushed drugs inhibited bacterial and/or fungal growth on agar plates. Twenty-eight of 29 crushed drugs reduced the total biomass when incubated with S. salivarius, and 28 of 29 crushed drugs inhibited C. albicans biofilm formation. Preformed biomass was reduced by ≥25% by seven of 29 drugs. Crushed drugs may unbalance oral ecosystems and contribute to oral inflammation. [Res Gerontol Nurs. 2018; 11(2):82-90.].
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Hellebrekers P, Hietbrink F, Vrisekoop N, Leenen LPH, Koenderman L. Neutrophil Functional Heterogeneity: Identification of Competitive Phagocytosis. Front Immunol 2017; 8:1498. [PMID: 29170663 PMCID: PMC5684128 DOI: 10.3389/fimmu.2017.01498] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 10/24/2017] [Indexed: 11/13/2022] Open
Abstract
Introduction Phagocytosis by neutrophils is a key process in the innate immune response against invading microorganisms. Despite reported heterogeneity in other neutrophils functions, little is known regarding differences in phagocytosis by individual cells. Therefore, we tested the hypothesis that heterogeneity is present in the neutrophil compartment in its potency to phagocytize bacteria. Methods Phagocytosis assays were performed in suspension with isolated neutrophils and Staphylococcus aureus expressing different fluorescent proteins at MOIs between 1 and 10. Repetitive addition of bacteria with different fluorescent proteins and MOIs was used to compare the phagocytic capacity of S. aureus-green fluorescent protein (GFP)-positive and negative neutrophils and exclude randomness. Results The percentage and mean fluorescence intensity (MFI) of S. aureus-GFP-positive neutrophils increased with higher MOIs. The increase in MFI was due to phagocytosis of multiple bacteria per neutrophil as was confirmed by confocal imaging. Sequential phagocytosis of GFP- and mCherry-expressing S. aureus showed a non-random process, as S. aureus-GFP-positive neutrophils preferentially phagocytized S. aureus-mCherry. Conclusion All neutrophils were able to phagocytize S. aureus, but some were much more potent than others. Therefore, at physiologically relevant MOIs these potent phagocytizing neutrophils will outcompete the uptake of bacteria by less competent cells in a process we propose to name “competitive phagocytosis.”
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Affiliation(s)
- Pien Hellebrekers
- Department of Respiratory Medicine, Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands.,Department of Surgery, University Medical Center Utrecht, Utrecht, Netherlands
| | - Falco Hietbrink
- Department of Surgery, University Medical Center Utrecht, Utrecht, Netherlands
| | - Nienke Vrisekoop
- Department of Respiratory Medicine, Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Luke P H Leenen
- Department of Surgery, University Medical Center Utrecht, Utrecht, Netherlands
| | - Leo Koenderman
- Department of Respiratory Medicine, Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
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Dotto C, Lombarte Serrat A, Cattelan N, Barbagelata MS, Yantorno OM, Sordelli DO, Ehling-Schulz M, Grunert T, Buzzola FR. The Active Component of Aspirin, Salicylic Acid, Promotes Staphylococcus aureus Biofilm Formation in a PIA-dependent Manner. Front Microbiol 2017; 8:4. [PMID: 28167931 PMCID: PMC5253544 DOI: 10.3389/fmicb.2017.00004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 01/03/2017] [Indexed: 01/10/2023] Open
Abstract
Aspirin has provided clear benefits to human health. But salicylic acid (SAL) -the main aspirin biometabolite- exerts several effects on eukaryote and prokaryote cells. SAL can affect, for instance, the expression of Staphylococcus aureus virulence factors. SAL can also form complexes with iron cations and it has been shown that different iron chelating molecules diminished the formation of S. aureus biofilm. The aim of this study was to elucidate whether the iron content limitation caused by SAL can modify the S. aureus metabolism and/or metabolic regulators thus changing the expression of the main polysaccharides involved in biofilm formation. The exposure of biofilm to 2 mM SAL induced a 27% reduction in the intracellular free Fe2+ concentration compared with the controls. In addition, SAL depleted 23% of the available free Fe2+ cation in culture media. These moderate iron-limited conditions promoted an intensification of biofilms formed by strain Newman and by S. aureus clinical isolates related to the USA300 and USA100 clones. The slight decrease in iron bioavailability generated by SAL was enough to induce the increase of PIA expression in biofilms formed by methicillin-resistant as well as methicillin-sensitive S. aureus strains. S. aureus did not produce capsular polysaccharide (CP) when it was forming biofilms under any of the experimental conditions tested. Furthermore, SAL diminished aconitase activity and stimulated the lactic fermentation pathway in bacteria forming biofilms. The polysaccharide composition of S. aureus biofilms was examined and FTIR spectroscopic analysis revealed a clear impact of SAL in a codY-dependent manner. Moreover, SAL negatively affected codY transcription in mature biofilms thus relieving the CodY repression of the ica operon. Treatment of mice with SAL induced a significant increase of S aureus colonization. It is suggested that the elevated PIA expression induced by SAL might be responsible for the high nasal colonization observed in mice. SAL-induced biofilms may contribute to S. aureus infection persistence in vegetarian individuals as well as in patients that frequently consume aspirin.
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Affiliation(s)
- Cristian Dotto
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Andrea Lombarte Serrat
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Natalia Cattelan
- Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI), Centro Científico Technológico Consejo Nacional de Investigaciones Científicas y Tócnicas (CTT CONICET La Plata), Universidad Nacional de La Plata La Plata, Argentina
| | - María S Barbagelata
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Osvaldo M Yantorno
- Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo de Fermentaciones Industriales (CINDEFI), Centro Científico Technológico Consejo Nacional de Investigaciones Científicas y Tócnicas (CTT CONICET La Plata), Universidad Nacional de La Plata La Plata, Argentina
| | - Daniel O Sordelli
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
| | - Monika Ehling-Schulz
- Functional Microbiology, Institute for Microbiology, University of Veterinary Medicine Vienna, Austria
| | - Tom Grunert
- Functional Microbiology, Institute for Microbiology, University of Veterinary Medicine Vienna, Austria
| | - Fernanda R Buzzola
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Instituto de Investigaciones en Microbiología y Parasitología Médica, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires Buenos Aires, Argentina
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Schoergenhofer C, Schwameis M, Lagler H, Jilma B. Editorial on low-dose acetylsalicylic acid treatment and impact on short-term mortality in Staphylococcus aureus bloodstream infection: a propensity score-matched cohort study. ANNALS OF TRANSLATIONAL MEDICINE 2016; 4:199. [PMID: 27294095 DOI: 10.21037/atm.2016.05.35] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The manuscript "Low-Dose Acetylsalicylic Acid Treatment and Impact on Short-Term Mortality in Staphylococcus aureus (S. aureus) Bloodstream Infection: A propensity Score-Matched Cohort Study" published in Critical Care Medicine by Osthoff et al. reported an association of aspirin intake with a reduced short-term mortality. Direct anti-microbial effects of aspirin and its metabolite salicylate were suggested in preclinical studies. Especially intriguing is the inclusion of a control group with Escherichia coli (E. coli) blood stream infections in this study, in which aspirin was not associated with an improved outcome. However, as other observational studies also reported benefits of aspirin in critically ill patients, randomized trials are needed to confirm the effects of low-dose aspirin.
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Affiliation(s)
- Christian Schoergenhofer
- 1 Department of Clinical Pharmacology, 2 Department of Internal Medicine I, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Michael Schwameis
- 1 Department of Clinical Pharmacology, 2 Department of Internal Medicine I, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Heimo Lagler
- 1 Department of Clinical Pharmacology, 2 Department of Internal Medicine I, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Bernd Jilma
- 1 Department of Clinical Pharmacology, 2 Department of Internal Medicine I, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
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Upadhyay A, Upadhyaya I, Kollanoor-Johny A, Venkitanarayanan K. Combating pathogenic microorganisms using plant-derived antimicrobials: a minireview of the mechanistic basis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:761741. [PMID: 25298964 PMCID: PMC4178913 DOI: 10.1155/2014/761741] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/05/2014] [Accepted: 08/08/2014] [Indexed: 12/19/2022]
Abstract
The emergence of antibiotic resistance in pathogenic bacteria has led to renewed interest in exploring the potential of plant-derived antimicrobials (PDAs) as an alternative therapeutic strategy to combat microbial infections. Historically, plant extracts have been used as a safe, effective, and natural remedy for ailments and diseases in traditional medicine. Extensive research in the last two decades has identified a plethora of PDAs with a wide spectrum of activity against a variety of fungal and bacterial pathogens causing infections in humans and animals. Active components of many plant extracts have been characterized and are commercially available; however, research delineating the mechanistic basis of their antimicrobial action is scanty. This review highlights the potential of various plant-derived compounds to control pathogenic bacteria, especially the diverse effects exerted by plant compounds on various virulence factors that are critical for pathogenicity inside the host. In addition, the potential effect of PDAs on gut microbiota is discussed.
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Affiliation(s)
- Abhinav Upadhyay
- Department of Animal Science, University of Connecticut, 3636 Horsebarn Hill Road Extension, Unit 4040, Storrs, CT 06269, USA
| | - Indu Upadhyaya
- Department of Animal Science, University of Connecticut, 3636 Horsebarn Hill Road Extension, Unit 4040, Storrs, CT 06269, USA
| | - Anup Kollanoor-Johny
- Department of Animal Science, University of Connecticut, 3636 Horsebarn Hill Road Extension, Unit 4040, Storrs, CT 06269, USA
| | - Kumar Venkitanarayanan
- Department of Animal Science, University of Connecticut, 3636 Horsebarn Hill Road Extension, Unit 4040, Storrs, CT 06269, USA
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Rapid and reliable identification of Staphylococcus aureus capsular serotypes by means of artificial neural network-assisted Fourier transform infrared spectroscopy. J Clin Microbiol 2013; 51:2261-6. [PMID: 23658268 DOI: 10.1128/jcm.00581-13] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus capsular polysaccharides (CP) are important virulence factors and represent putative targets for vaccine development. Therefore, the purpose of this study was to develop a high-throughput method to identify and discriminate the clinically important S. aureus capsular serotypes 5, 8, and NT (nontypeable). A comprehensive set of clinical isolates derived from different origins and control strains, representative for each serotype, were used to establish a CP typing system based on Fourier transform infrared (FTIR) spectroscopy and chemometric techniques. By combining FTIR spectroscopy with artificial neuronal network (ANN) analysis, a system was successfully established, allowing a rapid identification and discrimination of all three serotypes. The overall accuracy of the ANN-assisted FTIR spectroscopy CP typing system was 96.7% for the internal validation and 98.2% for the external validation. One isolate in the internal validation and one isolate in the external validation failed in the classification procedure, but none of the isolates was incorrectly classified. The present study demonstrates that ANN-assisted FTIR spectroscopy allows a rapid and reliable discrimination of S. aureus capsular serotypes. It is suitable for diagnostic as well as large-scale epidemiologic surveillance of S. aureus capsule expression and provides useful information with respect to chronicity of infection.
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Salicylic acid enhances Staphylococcus aureus extracellular adhesin protein expression. Microbes Infect 2011; 13:1073-80. [PMID: 21714946 DOI: 10.1016/j.micinf.2011.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 06/08/2011] [Accepted: 06/09/2011] [Indexed: 11/24/2022]
Abstract
One of the virulence factors required by Staphylococcus aureus at the early stages of infection is Eap, a secreted adhesin that binds many host proteins and is upregulated by the two-component regulatory system saeRS. The S. aureus Newman strain harbors a mutation in saeS that is thought to be responsible for the high level of Eap expression in this strain. This study was designed to ascertain whether salicylic acid (SAL) affects the expression of Eap and the internalization of S. aureus into epithelial cells. The strain Newman treated with SAL exhibited increased levels of eap transcription and protein expression. Furthermore, SAL treatment increased the eap promoter activity. SAL treatment enhanced Eap expression in the Newman and in other S. aureus strains that do not carry the mutation in saeS. Internalization of S. aureus eap and sae mutants into the MAC-T epithelial cells was significantly decreased compared with the wild-type counterparts. In conclusion, we demonstrated that a low concentration of SAL increased S. aureus Eap expression possibly due to enhancement of sae. SAL may create the conditions for S. aureus persistence in the host, not only by decreasing the capsular polysaccharide expression as shown before, but also by enhancing Eap expression.
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Tuchscherr L, Löffler B, Buzzola FR, Sordelli DO. Staphylococcus aureus adaptation to the host and persistence: role of loss of capsular polysaccharide expression. Future Microbiol 2010; 5:1823-32. [DOI: 10.2217/fmb.10.147] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A vast array of virulence factors enable Staphylococcus aureus to readily adapt to different environmental niches in diverse hosts. The cap gene cluster is present in almost all relevant clinical S. aureus isolates and capsular polysaccharide expression is apparent in isolates from patients with acute infection. The number of S. aureus isolates from patients with chronic infections that do not express capsular polysaccharide, however, is significantly high, indicating that loss of capsular polysaccharide expression may be a key S. aureus feature associated with persistence. The role of the loss of capsular polysaccharide expression as well as the emergence of other defined phenotypes and their relevance to persistence of S. aureus and chronicity of the infection is discussed in this article.
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Affiliation(s)
- Lorena Tuchscherr
- Institut für Medizinische Mikrobiologie, Universitätsklinikum Münster, Germany
| | - Bettina Löffler
- Institut für Medizinische Mikrobiologie, Universitätsklinikum Münster, Germany
| | - Fernanda R Buzzola
- Universidad de Buenos Aires, Paraguay, Buenos Aires, Argentina; Departamento de Microbiología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155 P-12, (C1121ABG) Buenos Aires, Argentina
- Consejo Nacional de Investigaciones, Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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