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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: 5] [Impact Index Per Article: 5.0] [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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Chan LC, Park M, Lee HK, Chaili S, Xiong YQ, Bayer AS, Proctor RA, Yeaman MR. Diflunisal Attenuates Virulence Factor Gene Regulation and Phenotypes in Staphylococcus aureus. Antibiotics (Basel) 2023; 12:902. [PMID: 37237805 PMCID: PMC10215304 DOI: 10.3390/antibiotics12050902] [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: 04/05/2023] [Revised: 05/04/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Virulence factor expression is integral to pathogenicity of Staphylococcus aureus. We previously demonstrated that aspirin, through its major metabolite, salicylic acid (SAL), modulates S. aureus virulence phenotypes in vitro and in vivo. We compared salicylate metabolites and a structural analogue for their ability to modulate S. aureus virulence factor expression and phenotypes: (i) acetylsalicylic acid (ASA, aspirin); (ii) ASA metabolites, salicylic acid (SAL), gentisic acid (GTA) and salicyluric acid (SUA); or (iii) diflunisal (DIF), a SAL structural analogue. None of these compounds altered the growth rate of any strain tested. ASA and its metabolites SAL, GTA and SUA moderately impaired hemolysis and proteolysis phenotypes in multiple S. aureus strain backgrounds and their respective deletion mutants. Only DIF significantly inhibited these virulence phenotypes in all strains. The kinetic profiles of ASA, SAL or DIF on expression of hla (alpha hemolysin), sspA (V8 protease) and their regulators (sigB, sarA, agr (RNAIII)) were assessed in two prototypic strain backgrounds: SH1000 (methicillin-sensitive S. aureus; MSSA) and LAC-USA300 (methicillin-resistant S. aureus; MRSA). DIF induced sigB expression which is coincident with the significant inhibition of RNAIII expression in both strains and precedes significant reductions in hla and sspA expression. The inhibited expression of these genes within 2 h resulted in the durable suppression of hemolysis and proteolysis phenotypes. These results indicate that DIF modulates the expression of key virulence factors in S. aureus via a coordinated impact on their relevant regulons and target effector genes. This strategy may hold opportunities to develop novel antivirulence strategies to address the ongoing challenge of antibiotic-resistant S. aureus.
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Affiliation(s)
- Liana C. Chan
- Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (L.C.C.); (H.K.L.)
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (Y.Q.X.)
- 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
| | - Mihyun Park
- Division of Molecular Medicine, Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (L.C.C.); (H.K.L.)
- 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; (L.C.C.); (H.K.L.)
- 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; (Y.Q.X.)
- 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; (Y.Q.X.)
- 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; (L.C.C.); (H.K.L.)
- Division of Infectious Diseases, Harbor-UCLA Medical Center, Torrance, CA 90502, USA; (Y.Q.X.)
- 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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Association Between Aspirin Use and Sepsis Outcomes: A National Cohort Study. Anesth Analg 2022; 135:110-117. [PMID: 35245223 DOI: 10.1213/ane.0000000000005943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Aspirin has anti-inflammatory and antiplatelet activities and directly inhibits bacterial growth. These effects of aspirin may improve survival in patients with sepsis. We retrospectively reviewed a large national health database to test the relationship between prehospital aspirin use and sepsis outcomes. METHODS We conducted a retrospective population-based cohort study using the National Health Insurance Research Database of Taiwan from 2001 to 2011 to examine the relationship between aspirin use before hospital admission and sepsis outcomes. The association between aspirin use and 90-day mortality in sepsis patients was determined using logistic regression models and weighting patients by the inverse probability of treatment weighting (IPTW) with the propensity score. Kaplan-Meier survival curves for each IPTW cohort were plotted for 90-day mortality. For sensitivity analyses, restricted mean survival times (RMSTs) were calculated based on Kaplan-Meier curves with 3-way IPTW analysis comparing current use, past use, and nonuse. RESULTS Of 52,982 patients with sepsis, 12,776 took aspirin before hospital admission (users), while 39,081 did not take any antiplatelet agents including aspirin before hospital admission (nonusers). After IPTW analysis, we found that when compared to nonusers, patients who were taking aspirin within 90 days before sepsis onset had a lower 90-day mortality rate (IPTW odds ratio [OR], 0.90; 95% confidence interval [CI], 0.88-0.93; P < .0001). Based on IPTW RMST analysis, nonusers had an average survival of 71.75 days, while current aspirin users had an average survival of 73.12 days. The difference in mean survival time was 1.37 days (95% CI, 0.50-2.24; P = .002). CONCLUSIONS Aspirin therapy before hospital admission is associated with a reduced 90-day mortality in sepsis patients.
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Donegan NP, Manna AC, Tseng CW, Liu GY, Cheung AL. CspA regulation of Staphylococcus aureus carotenoid levels and σ B activity is controlled by YjbH and Spx. Mol Microbiol 2019; 112:532-551. [PMID: 31074903 DOI: 10.1111/mmi.14273] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2019] [Indexed: 01/06/2023]
Abstract
Staphyloxanthin, a carotenoid in S. aureus, is a powerful antioxidant against oxidative stresses. The crtOPQMN operon driving pigment synthesis is under the control of σB . CspA, a cold shock protein, is known to control σB activity. To ascertain genes that regulate cspA, we screened a transposon library that exhibited reduced cspA expression and pigmentation. We found that the adaptor protein YjbH activates cspA expression. Spx, the redox-sensitive transcriptional regulator and a proteolytic target for YjbH and ClpXP, complexes with αCTD of RNAP prior to binding the cspA promoter to repress cspA activity. Increased cspA expression in trans in the inactive spx C10A mutant of JE2 did not enhance pigment production while it did in JE2, suggesting that cspA is downstream to Spx in pigmentation control. As the staphyloxanthin pigment is critical to S. aureus survival in human hosts, we demonstrated that the cspA and yjbH mutants survived less well than the parent in whole blood killing assay. Collectively, our studies suggest a pathway wherein YjbH and ClpXP proteolytically cleave Spx, a repressor of cspA transcription, to affect σB -dependent carotenoid expression, thus providing a critical link between intracellular redox sensing by Spx and carotenoid production to improve S. aureus survival during infections.
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Affiliation(s)
- Niles P Donegan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Adhar C Manna
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Ching Wen Tseng
- Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - George Y Liu
- Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ambrose L Cheung
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Repurposing the Nonsteroidal Anti-inflammatory Drug Diflunisal as an Osteoprotective, Antivirulence Therapy for Staphylococcus aureus Osteomyelitis. Antimicrob Agents Chemother 2016; 60:5322-30. [PMID: 27324764 DOI: 10.1128/aac.00834-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/16/2016] [Indexed: 02/05/2023] Open
Abstract
Staphylococcus aureus osteomyelitis is a common and debilitating invasive infection of bone. Treatment of osteomyelitis is confounded by widespread antimicrobial resistance and the propensity of bacteria to trigger pathological changes in bone remodeling that limit antimicrobial penetration to the infectious focus. Adjunctive therapies that limit pathogen-induced bone destruction could therefore limit morbidity and enhance traditional antimicrobial therapies. In this study, we evaluate the efficacy of the U.S. Food and Drug Administration-approved, nonsteroidal anti-inflammatory (NSAID) compound diflunisal in limiting S. aureus cytotoxicity toward skeletal cells and in preventing bone destruction during staphylococcal osteomyelitis. Diflunisal is known to inhibit S. aureus virulence factor production by the accessory gene regulator (agr) locus, and we have previously demonstrated that the Agr system plays a substantial role in pathological bone remodeling during staphylococcal osteomyelitis. Consistent with these observations, we find that diflunisal potently inhibits osteoblast cytotoxicity caused by S. aureus secreted toxins independently of effects on bacterial growth. Compared to commonly used NSAIDs, diflunisal is uniquely potent in the inhibition of skeletal cell death in vitro Moreover, local delivery of diflunisal by means of a drug-eluting, bioresorbable foam significantly limits bone destruction during S. aureus osteomyelitis in vivo Collectively, these data demonstrate that diflunisal potently inhibits skeletal cell death and bone destruction associated with S. aureus infection and may therefore be a useful adjunctive therapy for osteomyelitis.
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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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Eisen DP. Manifold beneficial effects of acetyl salicylic acid and nonsteroidal anti-inflammatory drugs on sepsis. Intensive Care Med 2012; 38:1249-57. [DOI: 10.1007/s00134-012-2570-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 03/19/2012] [Indexed: 12/31/2022]
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Riordan JT, Dupre JM, Cantore-Matyi SA, Kumar-Singh A, Song Y, Zaman S, Horan S, Helal NS, Nagarajan V, Elasri MO, Wilkinson BJ, Gustafson JE. Alterations in the transcriptome and antibiotic susceptibility of Staphylococcus aureus grown in the presence of diclofenac. Ann Clin Microbiol Antimicrob 2011; 10:30. [PMID: 21774834 PMCID: PMC3158543 DOI: 10.1186/1476-0711-10-30] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 07/21/2011] [Indexed: 11/24/2022] Open
Abstract
Background Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) which has been shown to increase the susceptibility of various bacteria to antimicrobials and demonstrated to have broad antimicrobial activity. This study describes transcriptome alterations in S. aureus strain COL grown with diclofenac and characterizes the effects of this NSAID on antibiotic susceptibility in laboratory, clinical and diclofenac reduced-susceptibility (DcRS) S. aureus strains. Methods Transcriptional alterations in response to growth with diclofenac were measured using S. aureus gene expression microarrays and quantitative real-time PCR. Antimicrobial susceptibility was determined by agar diffusion MICs and gradient plate analysis. Ciprofloxacin accumulation was measured by fluorescence spectrophotometry. Results Growth of S. aureus strain COL with 80 μg/ml (0.2 × MIC) of diclofenac resulted in the significant alteration by ≥2-fold of 458 genes. These represented genes encoding proteins for transport and binding, protein and DNA synthesis, and the cell envelope. Notable alterations included the strong down-regulation of antimicrobial efflux pumps including mepRAB and a putative emrAB/qacA-family pump. Diclofenac up-regulated sigB (σB), encoding an alternative sigma factor which has been shown to be important for antimicrobial resistance. Staphylococcus aureus microarray metadatabase (SAMMD) analysis further revealed that 46% of genes differentially-expressed with diclofenac are also σB-regulated. Diclofenac altered S. aureus susceptibility to multiple antibiotics in a strain-dependent manner. Susceptibility increased for ciprofloxacin, ofloxacin and norfloxacin, decreased for oxacillin and vancomycin, and did not change for tetracycline or chloramphenicol. Mutation to DcRS did not affect susceptibility to the above antibiotics. Reduced ciprofloxacin MICs with diclofenac in strain BB255, were not associated with increased drug accumulation. Conclusions The results of this study suggest that diclofenac influences antibiotic susceptibility in S. aureus, in part, by altering the expression of regulatory and structural genes associated with cell wall biosynthesis/turnover and transport.
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Affiliation(s)
- James T Riordan
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620, USA.
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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: 0.4] [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: 3.1] [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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Salicylic acid diminishes Staphylococcus aureus capsular polysaccharide type 5 expression. Infect Immun 2009; 78:1339-44. [PMID: 20008532 DOI: 10.1128/iai.00245-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Capsular polysaccharides (CP) of serotypes 5 (CP5) and 8 (CP8) are major Staphylococcus aureus virulence factors. Previous studies have shown that salicylic acid (SAL), the main aspirin metabolite, affects the expression of certain bacterial virulence factors. In the present study, we found that S. aureus strain Reynolds (CP5) cultured with SAL was internalized by MAC-T cells in larger numbers than strain Reynolds organisms not exposed to SAL. Furthermore, the internalization of the isogenic nonencapsulated Reynolds strain into MAC-T cells was not significantly affected by preexposure to SAL. Pretreatment of S. aureus strain Newman with SAL also enhanced internalization into MAC-T cells compared with that of untreated control strains. Using strain Newman organisms, we evaluated the activity of the major cap5 promoter, which was significantly decreased upon preexposure to SAL. Diminished transcription of mgrA and upregulation of the saeRS transcript, both global regulators of CP expression, were found in S. aureus cultured in the presence of SAL, as ascertained by real-time PCR analysis. In addition, CP5 production by S. aureus Newman was also decreased by treatment with SAL. Collectively, our data demonstrate that exposure of encapsulated S. aureus strains to low concentrations of SAL reduced CP production, thus unmasking surface adhesins and leading to an increased capacity of staphylococci to invade epithelial cells. The high capacity of internalization of the encapsulated S. aureus strains induced by SAL pretreatment may contribute to the persistence of bacteria in certain hosts.
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Vandecasteele SJ, Boelaert JR, De Vriese AS. Staphylococcus aureusInfections in Hemodialysis: What a Nephrologist Should Know: Table 1. Clin J Am Soc Nephrol 2009; 4:1388-400. [DOI: 10.2215/cjn.01590309] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Eisen DP, Corey GR, McBryde ES, Fowler VG, Miro JM, Cabell CH, Street AC, Paiva MG, Ionac A, Tan RS, Tribouilloy C, Pachirat O, Jones SB, Chipigina N, Naber C, Pan A, Ravasio V, Gattringer R, Chu VH, Bayer AS. Reduced valve replacement surgery and complication rate in Staphylococcus aureus endocarditis patients receiving acetyl-salicylic acid. J Infect 2009; 58:332-8. [DOI: 10.1016/j.jinf.2009.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 12/29/2008] [Accepted: 03/07/2009] [Indexed: 10/21/2022]
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Development of shuttle vectors for evaluation of essential regulator regulated gene expression in Staphylococcus aureus. Plasmid 2009; 61:188-92. [PMID: 19245820 DOI: 10.1016/j.plasmid.2009.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 01/27/2009] [Accepted: 02/12/2009] [Indexed: 11/22/2022]
Abstract
We describe the construction of a series of shuttle vectors for Staphylococcus aureus. In order to determine transcriptional regulation by essential regulators, we constructed promoterless luxABCDE reporter system using a TetR-regulated antisense RNA expression vector, pJYJ909, which is composed of S. aureus plasmid pE194, the Gram(-) plasmid pUC18, a TetR regulatory cassette, and Pxyl/teto-driven yhcS antisense expression construct. The reformed shuttle vector was utilized to construct an opuCA promoter-luxABCDE fusion and simultaneously examine transcriptional regulation by measuring bioluminescence intensity during down-regulating yhcSR. In addition, we utilized the same plasmid, pJYJ909, and constructed a Pspac-driven constant expression system, which allows us to determine the complementary effect of overexpression of opuCA operon modulated by yhcSR. These plasmids provide important tools for elucidating regulatory mechanisms for genes that are essential for bacterial growth in S. aureus.
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Pepin J, Tremblay V, Bechard D, Rodier F, Walker C, Dufresne D, Lafontaine A, Li N, Lacroix C, Lanthier L. Chronic antiplatelet therapy and mortality among patients with infective endocarditis. Clin Microbiol Infect 2009; 15:193-9. [DOI: 10.1111/j.1469-0691.2008.02665.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Regulation of the mazEF toxin-antitoxin module in Staphylococcus aureus and its impact on sigB expression. J Bacteriol 2009; 191:2795-805. [PMID: 19181798 DOI: 10.1128/jb.01713-08] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In Staphylococcus aureus, the sigB operon codes for the alternative sigma factor sigma(B) and its regulators that enable the bacteria to rapidly respond to environmental stresses via redirection of transcriptional priorities. However, a full model of sigma(B) regulation in S. aureus has not yet emerged. Earlier data has suggested that mazEF, a toxin-antitoxin (TA) module immediately upstream of the sigB operon, was transcribed with the sigB operon. Here we demonstrate that the promoter P(mazE) upstream of mazEF is essential for full sigma(B) activity and that instead of utilizing autorepression typical of TA systems, sigB downregulates this promoter, providing a negative-feedback loop for sigB to repress its own transcription. We have also found that the transcriptional regulator SarA binds and activates P(mazE). In addition, P(mazE) was shown to respond to environmental and antibiotic stresses in a way that provides an additional layer of control over sigB expression. The antibiotic response also appears to occur in two other TA systems in S. aureus, indicating a shared mechanism of regulation.
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