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Sample records for aureus induced pyemia

  1. A pig model of acute Staphylococcus aureus induced pyemia

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    Nielsen, O. L.; Iburg, T.; Aalbæk, B.

    2009-01-01

    was a consequence of both the intravenous route of inoculation and the presence of pulmonary intravascular macrophages. Inoculation of bacteria induced formation of acute microabscesses in the lungs, spleen and liver, but not in the kidneys or bones. No generalized inflammatory response was recorded, i.e. IL-6...... was not detected in the blood and C-reactive protein did not increase, probably because of the short time course of the study. Conclusion: This study demonstrates the successful induction of acute pyemia (microabscesses), and forms a basis for future experiments that should include inoculation with strains of S...

  2. Radiation induced changes in alpha toxin of Staphylococcus aureus 3750

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    Sherekar, S.V.; Bhushan, B.; Gore, M.S. (Bhabha Atomic Research Centre, Bombay (India). Biochemistry and Food Technology Div.)

    1981-06-01

    Influence of ..gamma..-radiation and heat on haemolytic activity of purified alpha toxin from staphylococcus aureus 3750 cells was studied. Heat treatment at 60deg C for 1 min resulted in 99% inactivation of alpha toxin, while exposure to ..gamma..-radiation caused linear decline in activity, 40 krad causing 50% inactivation. Urea treatment reversed the heat induced inactivation but did not reactivate the irradiated toxin. However, the irradiated toxin retained its antigenicity, thus indicating its potential for the preparation of toxoid against alpha toxin.

  3. Extracellular vesicles derived from Staphylococcus aureus induce atopic dermatitis-like skin inflammation.

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    Hong, S-W; Kim, M-R; Lee, E-Y; Kim, J H; Kim, Y-S; Jeon, S G; Yang, J-M; Lee, B-J; Pyun, B-Y; Gho, Y S; Kim, Y-K

    2011-03-01

    Recently, we found that Staphylococcus aureus produces extracellular vesicles (EV) that contain pathogenic proteins. Although S. aureus infection has been linked with atopic dermatitis (AD), the identities of the causative agents from S. aureus are controversial. We evaluated whether S. aureus-derived EV are causally related to the pathogenesis of AD. Extracellular vesicles were isolated by the ultracentrifugation of S. aureus culture media. The EV were applied three times per week to tape-stripped mouse skin. Inflammation and immune dysfunction were evaluated 48 h after the final application in hairless mice. Extracellular vesicles-specific IgE levels were measured by ELISA in AD patients and healthy subjects. The in vitro application of S. aureus EV increased the production of pro-inflammatory mediators (IL-6, thymic stromal lymphopoietin, macrophage inflammatory protein-1α, and eotaxin) by dermal fibroblasts. The in vivo application of S. aureus EV after tape stripping caused epidermal thickening with infiltration of the dermis by mast cells and eosinophils in mice. These changes were associated with the enhanced cutaneous production of IL-4, IL-5, IFN-γ, and IL-17. Interestingly, the serum levels of S. aureus EV-specific IgE were significantly increased in AD patients relative to healthy subjects. These results indicate that S. aureus EV induce AD-like inflammation in the skin and that S. aureus-derived EV are a novel diagnostic and therapeutic target for the control of AD. © 2010 John Wiley & Sons A/S.

  4. Heat-killed Staphylococcus aureus reduces atherosclerosis by inducing anti-inflammatory macrophages

    NARCIS (Netherlands)

    Frodermann, V.; van Duijn, J.; van Puijvelde, G. H. M.; van Santbrink, P. J.; Lagraauw, H. M.; de Vries, Margreet R; Quax, P. H. A.; Bot, I.; Foks, A. C.; de Jager, S. C. A.; Kuiper, J.

    Background Staphylococcus aureus cell wall components can induce IL-10 responses by immune cells, which may be atheroprotective. Therefore, in this study, we investigated whether heat-killed S. aureus (HK-SA) could inhibit the development of atherosclerosis. Methods Atherosclerosis-susceptible LDL

  5. PREVALENCE OF INDUCIBLE CLINDAMYCIN RESISTANCE AMONG STAPHYLOCOCCUS AUREUS ISOLATES RESISTANT TO ERYTHROMYCIN

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    Syed Asim M

    2017-04-01

    Full Text Available BACKGROUND Clindamycin is an effective drug to treat Methicillin-Resistant Staphylococcus Aureus (MRSA. Reporting S. aureus as susceptible to clindamycin without checking for inducible clindamycin resistance may lead to therapeutic failure. Therefore, D-test is used to screen inducible clindamycin resistance. MATERIALS AND METHODS All the S. aureus isolates resistant to erythromycin were taken. Erythromycin (15 μg disc and clindamycin (2 μg disc were placed 15 mm apart on Mueller-Hinton agar plates as per CLSI guidelines and incubated at 37°C for 18-24 hours. Flattening of zone (D shape around clindamycin was taken as D-test positive. RESULTS Out of 270 S. aureus isolates, 80 were resistant to erythromycin. D-test was positive in 29 isolates, out of which 23 were MRSA. These MRSA isolates were also resistant to most of the other routinely used antibiotics. This study showed that inducible clindamycin resistance is as high as 36.2% in erythromycin resistant S. aureus and 10.7% among S. aureus as such. CONCLUSION We conclude that this simple and effective method can be implemented for accurate identification of inducible clindamycin resistance in S. aureus to prevent treatment failure. Clinical laboratories should guide the clinicians about the inducible clindamycin resistance by performing D-test routinely and prevent misuse of antibiotics.

  6. Isorhamnetin Attenuates Staphylococcus aureus-Induced Lung Cell Injury by Inhibiting Alpha-Hemolysin Expression.

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    Jiang, Lanxiang; Li, Hongen; Wang, Laiying; Song, Zexin; Shi, Lei; Li, Wenhua; Deng, Xuming; Wang, Jianfeng

    2016-03-01

    Staphylococcus aureus, like other gram-positive pathogens, has evolved a large repertoire of virulence factors as a powerful weapon to subvert the host immune system, among which alpha-hemolysin (Hla), a secreted pore-forming cytotoxin, plays a preeminent role. We observed a concentration-dependent reduction in Hla production by S. aureus in the presence of sub-inhibitory concentrations of isorhamnetin, a flavonoid from the fruits of Hippophae rhamnoides L., which has little antibacterial activity. We further evaluate the effect of isorhamnetin on the transcription of the Hla-encoding gene hla and RNAIII, an effector molecule in the agr system. Isorhamnetin significantly down-regulated RNAIII expression and subsequently inhibited hla transcription. In a co-culture of S. aureus and lung cells, topical isorhamnetin treatment protected against S. aureus-induced cell injury. Isorhamnetin may represent a leading compound for the development of anti-virulence drugs against S. aureus infections.

  7. Staphylococcus aureus - induced tumor necrosis factor - related apoptosis - inducing ligand expression mediates apoptosis and caspase-8 activation in infected osteoblasts

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    Alexander, Emily H; Rivera, F Andrea; Marriott, Ian; Anguita, Juan; Bost, Kenneth L; Hudson, Michael C

    2003-01-01

    Background Staphylococcus aureus infection of normal osteoblasts induces expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Results Normal osteoblasts were incubated in the presence of purified bacterial products over a range of concentrations. Results demonstrate that purified surface structures and a selected superantigen present in the extracellular environment are not capable of inducing TRAIL expression by osteoblasts. Osteoblasts were co-cultured with S. aureus at various multiplicities of infection utilizing cell culture chamber inserts. Results of those experiments suggest that direct contact between bacteria and osteoblasts is necessary for optimal TRAIL induction. Finally, S. aureus infection of osteoblasts in the presence of anti-TRAIL antibody demonstrates that TRAIL mediates caspase-8 activation and apoptosis of infected cells. Conclusions Collectively, these findings suggest a mechanism whereby S. aureus mediates bone destruction via induction of osteoblast apoptosis. PMID:12697056

  8. Staphylococcus aureus - induced tumor necrosis factor - related apoptosis - inducing ligand expression mediates apoptosis and caspase-8 activation in infected osteoblasts

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    Bost Kenneth L

    2003-04-01

    Full Text Available Abstract Background Staphylococcus aureus infection of normal osteoblasts induces expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL. Results Normal osteoblasts were incubated in the presence of purified bacterial products over a range of concentrations. Results demonstrate that purified surface structures and a selected superantigen present in the extracellular environment are not capable of inducing TRAIL expression by osteoblasts. Osteoblasts were co-cultured with S. aureus at various multiplicities of infection utilizing cell culture chamber inserts. Results of those experiments suggest that direct contact between bacteria and osteoblasts is necessary for optimal TRAIL induction. Finally, S. aureus infection of osteoblasts in the presence of anti-TRAIL antibody demonstrates that TRAIL mediates caspase-8 activation and apoptosis of infected cells. Conclusions Collectively, these findings suggest a mechanism whereby S. aureus mediates bone destruction via induction of osteoblast apoptosis.

  9. Development of the immune response in pneumonia induced by Staphylococcus aureus (part 3

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    A.E. Abaturov

    2017-05-01

    Full Text Available The article analyzes the key role of pro-inflammatory and anti-inflammatory cytokines in the development of immune response in pneumonia caused by Staphylococcus aureus based on the literature data. Genes associated with a predisposition to staphylococcal infection and/or determining its course are considered. Signal pathways inducing the production of interferons I, II and III type participating in elimination of Staphylococcus aureus are described.

  10. Histopathology of mammary gland in Staphylococcus aureus induced mastitis in mice

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    Jayaraj Fakkirappa Chinchali

    2014-02-01

    Full Text Available Objective: To investigate the histopathological changes of mouse mammary tissue damage in dose and durational pathogenicity of Staphylococcus aureus (S. aureus inoculums. Methods: The minimal tissue inflammation dose of S. aureus inoculum was determined by inoculating the lactating mice mammary gland to observe the mortality rate at 24, 48, 72 and 96 h of infection for each inoculum dilutions. To study dose pathogenicity, lactating mice were divided into one control and four induced groups of 5 mice each. S. aureus inoculums doses of 0.8伊101, 1.4 伊102, 2伊102 and 2.8伊103 colony forming unit were inoculated to the induced groups II, III, IV and V respectively. Mice were sacrificed and mammary gland tissues were harvested after 48 h of infection. Similarly to study of durational pathogenicity, a dose of 2伊102 colony forming unit of S. aureus inoculums was inoculated to the induced groups II, III, IV and V respectively. Mice were sacrificed and mammary gland tissues were harvested after 24, 48, 72 and 96 h of infection. Body and mammary gland were weighed and histopathological responses of the tissue damage were observed for both dose and durational pathogenicity ’s of S. aureus inoculums. Results: The observations indicated mastitis symptoms, decrease in body and mammary gland weights. Histopathological evidences revealed massive infiltration of polymorphonuclear neutrophil leukocytes, damage of alveoli and secretory products as the doses and durations of S. aureus inoculum increased compared to the control. Conclusions: The present study revealed that damage in mammary gland tissue of mice increased as the dose and duration of S. aureus inoculums increased.

  11. Staphylococcus aureus induces IL-8 expression through its lipoproteins in the human intestinal epithelial cell, Caco-2.

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    Kang, Seok-Seong; Noh, Su Young; Park, Ok-Jin; Yun, Cheol-Heui; Han, Seung Hyun

    2015-09-01

    Staphylococcus aureus can cause the intestinal inflammatory diseases. However, little is known about the molecular mechanism of S. aureus infection in the intestine. In the present study, we investigated whether S. aureus could stimulate human intestinal epithelial cells triggering inflammation. When the human intestinal epithelial cell-line, Caco-2, and the primary colon cells were stimulated with ethanol-inactivated S. aureus, IL-8 expression was induced in a dose-dependent manner. The inactivated S. aureus preferentially stimulated Toll-like receptor (TLR) 2 rather than TLR4. Lipoproteins, lipoteichoic acid (LTA), and peptidoglycan (PGN) are considered as potential TLR2 ligands of S. aureus. Interestingly, S aureus lipoproteins and Pam2CSK4 mimicking Gram-positive bacterial lipoproteins, but not LTA and PGN of S. aureus, significantly induced IL-8 expression in Caco-2 cells. Furthermore, lipoprotein-deficient S. aureus mutant strain failed to induce IL-8 production. Collectively, these results suggest that S. aureus stimulates the human intestinal epithelial cells to induce the chemokine IL-8 production through its lipoproteins, potentially contributing the development of intestinal inflammation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Human SAP is a novel peptidoglycan recognition protein that induces complement- independent phagocytosis of Staphylococcus aureus

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    An, Jang-Hyun; Kurokawa, Kenji; Jung, Dong-Jun; Kim, Min-Jung; Kim, Chan-Hee; Fujimoto, Yukari; Fukase, Koichi; Coggeshall, K. Mark; Lee, Bok Luel

    2014-01-01

    The human pathogen Staphylococcus aureus is responsible for many community-acquired and hospital-associated infections and is associated with high mortality. Concern over the emergence of multidrug-resistant strains has renewed interest in the elucidation of host mechanisms that defend against S. aureus infection. We recently demonstrated that human serum mannose-binding lectin (MBL) binds to S. aureus wall teichoic acid (WTA), a cell wall glycopolymer, a discovery that prompted further screening to identify additional serum proteins that recognize S. aureus cell wall components. In this report, we incubated human serum with 10 different S. aureus mutants and determined that serum amyloid P component (SAP) bound specifically to a WTA-deficient S. aureus ΔtagO mutant, but not to tagO-complemented, WTA-expressing cells. Biochemical characterization revealed that SAP recognizes bacterial peptidoglycan as a ligand and that WTA inhibits this interaction. Although SAP binding to peptidoglycan was not observed to induce complement activation, SAP-bound ΔtagO cells were phagocytosed by human polymorphonuclear leukocytes in an Fcγ receptor-dependent manner. These results indicate that SAP functions as a host defense factor, similar to other peptidoglycan recognition proteins and nucleotide-binding oligomerization domain (NOD)-like receptors. PMID:23966633

  13. Exposure of Staphylococcus aureus to subinhibitory concentrations of β-lactam antibiotics induces heterogeneous vancomycin-intermediate Staphylococcus aureus.

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    Roch, Mélanie; Clair, Perrine; Renzoni, Adriana; Reverdy, Marie-Elisabeth; Dauwalder, Olivier; Bes, Michèle; Martra, Annie; Freydière, Anne-Marie; Laurent, Frédéric; Reix, Philippe; Dumitrescu, Oana; Vandenesch, François

    2014-09-01

    Glycopeptides are known to select for heterogeneous vancomycin-intermediate Staphylococcus aureus (h-VISA) from susceptible strains. In certain clinical situations, h-VISA strains have been isolated from patients without previous exposure to glycopeptides, such as cystic fibrosis patients, who frequently receive repeated treatments with beta-lactam antibiotics. Our objective was to determine whether prolonged exposure to beta-lactam antibiotics can induce h-VISA. We exposed 3 clinical vancomycin-susceptible methicillin-resistant Staphylococcus aureus (MRSA) strains to ceftazidime, ceftriaxone, imipenem, and vancomycin (as a control) at subinhibitory concentrations for 18 days in vitro. Population analyses showed progressive increases in vancomycin resistance; seven of the 12 derived strains obtained after induction were classified as h-VISA according to the following criteria: area under the curve (AUC) on day 18/AUC of Mu3 of ≥90% and/or growth on brain heart infusion (BHI) agar with 4 mg/liter vancomycin. The derived isolates had thickened cell walls proportional to the level of glycopeptide resistance. Genes known to be associated with glycopeptide resistance (vraSR, yvqF, SA1703, graRS, walKR, and rpoB) were PCR sequenced; no de novo mutations were observed upon beta-lactam exposure. To determine whether trfA, a gene encoding a glycopeptide resistance factor, was essential in the selection of h-VISA upon beta-lactam pressure, a trfA-knockout strain was generated by allelic replacement. Indeed, beta-lactam exposure of this mutated strain showed no capacity to induce vancomycin resistance. In conclusion, these results showed that beta-lactam antibiotics at subinhibitory concentrations can induce intermediate vancomycin resistance in vitro. This induction required an intact trfA locus. Our results suggest that prior use of beta-lactam antibiotics can compromise vancomycin efficacy in the treatment of MRSA infections. Copyright © 2014, American Society for

  14. Staphylococcus aureus induces eosinophil cell death mediated by α-hemolysin.

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    Lynne R Prince

    Full Text Available Staphylococcus aureus, a major human pathogen, exacerbates allergic disorders, including atopic dermatitis, nasal polyps and asthma, which are characterized by tissue eosinophilia. Eosinophils, via their destructive granule contents, can cause significant tissue damage, resulting in inflammation and further recruitment of inflammatory cells. We hypothesised that the relationship between S. aureus and eosinophils may contribute to disease pathology. We found that supernatants from S. aureus (SH1000 strain cultures cause rapid and profound eosinophil necrosis, resulting in dramatic cell loss within 2 hours. This is in marked contrast to neutrophil granulocytes where no significant cell death was observed (at equivalent dilutions. Supernatants prepared from a strain deficient in the accessory gene regulator (agr that produces reduced levels of many important virulence factors, including the abundantly produced α-hemolysin (Hla, failed to induce eosinophil death. The role of Hla in mediating eosinophil death was investigated using both an Hla deficient SH1000-modified strain, which did not induce eosinophil death, and purified Hla, which induced concentration-dependent eosinophil death via both apoptosis and necrosis. We conclude that S. aureus Hla induces aberrant eosinophil cell death in vitro and that this may increase tissue injury in allergic disease.

  15. Staphylococcus aureus induces eosinophil cell death mediated by α-hemolysin.

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    Prince, Lynne R; Graham, Kirstie J; Connolly, John; Anwar, Sadia; Ridley, Robert; Sabroe, Ian; Foster, Simon J; Whyte, Moira K B

    2012-01-01

    Staphylococcus aureus, a major human pathogen, exacerbates allergic disorders, including atopic dermatitis, nasal polyps and asthma, which are characterized by tissue eosinophilia. Eosinophils, via their destructive granule contents, can cause significant tissue damage, resulting in inflammation and further recruitment of inflammatory cells. We hypothesised that the relationship between S. aureus and eosinophils may contribute to disease pathology. We found that supernatants from S. aureus (SH1000 strain) cultures cause rapid and profound eosinophil necrosis, resulting in dramatic cell loss within 2 hours. This is in marked contrast to neutrophil granulocytes where no significant cell death was observed (at equivalent dilutions). Supernatants prepared from a strain deficient in the accessory gene regulator (agr) that produces reduced levels of many important virulence factors, including the abundantly produced α-hemolysin (Hla), failed to induce eosinophil death. The role of Hla in mediating eosinophil death was investigated using both an Hla deficient SH1000-modified strain, which did not induce eosinophil death, and purified Hla, which induced concentration-dependent eosinophil death via both apoptosis and necrosis. We conclude that S. aureus Hla induces aberrant eosinophil cell death in vitro and that this may increase tissue injury in allergic disease.

  16. Dietary Omega-3 Fatty Acids Increase Survival and Decrease Bacterial Load in Mice Subjected to Staphylococcus aureus-Induced Sepsis.

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    Svahn, Sara L; Ulleryd, Marcus A; Grahnemo, Louise; Ståhlman, Marcus; Borén, Jan; Nilsson, Staffan; Jansson, John-Olov; Johansson, Maria E

    2016-04-01

    Sepsis caused by Staphylococcus aureus is increasing in incidence. With the alarming use of antibiotics,S. aureus is prone to become methicillin resistant. Antibiotics are the only widely used pharmacological treatment for sepsis. Interestingly, mice fed high-fat diet (HFD) rich in polyunsaturated fatty acids have better survival of S. aureus-induced sepsis than mice fed HFD rich in saturated fatty acids (HFD-S). To investigate what component of polyunsaturated fatty acids, i.e., omega-3 or omega-6 fatty acids, exerts beneficial effects on the survival of S. aureus-induced sepsis, mice were fed HFD rich in omega-3 or omega-6 fatty acids for 8 weeks prior to inoculation with S. aureus Further, mice fed HFD-S were treated with omega-3 fatty acid metabolites known as resolvins. Mice fed HFD rich in omega-3 fatty acids had increased survival and decreased bacterial loads compared to those for mice fed HFD-S after S. aureus-induced sepsis. Furthermore, the bacterial load was decreased in resolvin-treated mice fed HFD-S after S. aureus-induced sepsis compared with that in mice treated with vehicle. Dietary omega-3 fatty acids increase the survival of S. aureus-induced sepsis by reversing the deleterious effect of HFD-S on mouse survival. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  17. Reversible antibiotic tolerance induced in Staphylococcus aureus by concurrent drug exposure

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    Haaber, Jakob Krause; Friberg, Cathrine; McCreary, Mark

    2015-01-01

    antibiotic that targets the coinfecting pathogen. While investigating factors that affect bacterial antibiotic sensitivity, we discovered that susceptibility of S. aureus to vancomycin is reduced by concurrent exposure to colistin, a cationic peptide antimicrobial employed to treat infections by Gram......UNLABELLED: Resistance of Staphylococcus aureus to beta-lactam antibiotics has led to increasing use of the glycopeptide antibiotic vancomycin as a life-saving treatment for major S. aureus infections. Coinfection by an unrelated bacterial species may necessitate concurrent treatment with a second......] strains). As colistin-induced vancomycin tolerance is reversible, it may not be detected by routine sensitivity testing and may be responsible for treatment failure at vancomycin doses expected to be clinically effective based on such routine testing. IMPORTANCE: Commonly, antibiotic resistance...

  18. The importance of inducible clindamycin resistance in enterotoxin positive S. aureus isolated from clinical samples

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    Memariani M

    2009-07-01

    Full Text Available "nBackground: Clindamycin is a suitable antibiotic for treatment of skin and soft tissue infections. Moreover, it can suppress toxin production in many pathogenic bacteria such as S. aureus. There are two mechanisms of resistance in this antibiotic. Constitutive resistance can be detected by standard disk diffusion method but in the case of inducible resistance, D-test should be carried out. The main aim of this study is to determine prevalence of clindamycin inducible resistance among methicillin resistant and susceptible isolates of S. aureus isolated from different clinical samples. "nMethods: A total of 87 clinical isolates from clinical samples were collected. Methicillin resistance was determined using standard disk diffusion method. Subsequently, D-test was carried out according to CLSI guideline. Presence of the sea gene (enterotoxin A was detected by PCR using specific primers. "nResults: Out of 87 isolates, 18(20.7% were clindamycin inducible resistant while constitutive resistance was detected among 21(24.1% isolates. The 95% Confidence intervals for the proportion of inducible clindamycin resistance among clinical isolates of S. aureus was 12.2% to 29.2%. The inducible phenotype in MRSA isolates was more common than that of MSSA isolates (33.3% vs 5.1%.Significant differences were found between prevalence of inducible clindamycin resistance and type of infection (p=0.045. Importantly, there was a significant correlation between sea gene and the constitutive/inducible resistance (p<0.0001. "nConclusions: Due to the high prevalence of clindamycin inducible resistance among clinical isolates of S. aureus, we recommend D-test to avoid treatment failure.

  19. Biofilm Matrix Exoproteins Induce a Protective Immune Response against Staphylococcus aureus Biofilm Infection

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    Gil, Carmen; Solano, Cristina; Burgui, Saioa; Latasa, Cristina; García, Begoña; Toledo-Arana, Alejandro

    2014-01-01

    The Staphylococcus aureus biofilm mode of growth is associated with several chronic infections that are very difficult to treat due to the recalcitrant nature of biofilms to clearance by antimicrobials. Accordingly, there is an increasing interest in preventing the formation of S. aureus biofilms and developing efficient antibiofilm vaccines. Given the fact that during a biofilm-associated infection, the first primary interface between the host and the bacteria is the self-produced extracellular matrix, in this study we analyzed the potential of extracellular proteins found in the biofilm matrix to induce a protective immune response against S. aureus infections. By using proteomic approaches, we characterized the exoproteomes of exopolysaccharide-based and protein-based biofilm matrices produced by two clinical S. aureus strains. Remarkably, results showed that independently of the nature of the biofilm matrix, a common core of secreted proteins is contained in both types of exoproteomes. Intradermal administration of an exoproteome extract of an exopolysaccharide-dependent biofilm induced a humoral immune response and elicited the production of interleukin 10 (IL-10) and IL-17 in mice. Antibodies against such an extract promoted opsonophagocytosis and killing of S. aureus. Immunization with the biofilm matrix exoproteome significantly reduced the number of bacterial cells inside a biofilm and on the surrounding tissue, using an in vivo model of mesh-associated biofilm infection. Furthermore, immunized mice also showed limited organ colonization by bacteria released from the matrix at the dispersive stage of the biofilm cycle. Altogether, these data illustrate the potential of biofilm matrix exoproteins as a promising candidate multivalent vaccine against S. aureus biofilm-associated infections. PMID:24343648

  20. Pseudomonas aeruginosa induces pigment production and enhances virulence in a white phenotypic variant of Staphylococcus aureus

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    Antonic V

    2013-11-01

    Full Text Available Vlado Antonic,1–3 Alexander Stojadinovic,3–5 Binxue Zhang,1–3 Mina J Izadjoo,1–3,5 Mohammad Alavi1–3 1Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA; 2Diagnostic and Translational Research Center, Gaithersburg, MD, USA; 3Combat Wound Initiative Program, Bethesda, MD, USA; 4Walter Reed National Military Medical Center, Bethesda, MD, USA; 5Uniformed Services University of the Health Sciences, Bethesda, MD, USA Abstract: Staphyloxanthin is a virulence factor which protects Staphylococcus aureus in stress conditions. We isolated two pigment variants of S. aureus and one strain of Pseudomonas aeruginosa from a single wound infection. S. aureus variants displayed white and yellow colony phenotypes. The sequence of the operons for staphyloxanthin synthesis indicated that coding and promoter regions were identical between the two pigment variants. Quorum sensing controls pigment synthesis in some bacteria. It is also shown that P. aeruginosa quorum-sensing molecules affect S. aureus transcription. We explored whether the co-infecting P. aeruginosa can affect pigment production in the white S. aureus variant. In co-culture experiments between the white variants and a selected number of Gram-positive and Gram-negative bacteria, only P. aeruginosa induced pigment production in the white variant. Gene expression analysis of the white variant did not indicate upregulation of the crtM and other genes known to be involved in pigment production (sigB, sarA, farnesyl pyrophosphate synthase gene [FPP-synthase], hfq. In contrast, transcription of the catalase gene was significantly upregulated after co-culture. P. aeruginosa-induced pigment synthesis and catalase upregulation correlated with increased resistance to polymyxin B, hydrogen peroxide, and the intracellular environment of macrophages. Our data indicate the presence of silent but functional staphyloxanthin synthesis machinery in a white phenotypic variant

  1. The Impact of Staphylococcus aureus-Associated Molecular Patterns on Staphylococcal Superantigen-Induced Toxic Shock Syndrome and Pneumonia

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    Ashenafi Y. Tilahun

    2014-01-01

    Full Text Available Staphylococcus aureus is capable of causing a spectrum of human illnesses. During serious S. aureus infections, the staphylococcal pathogen-associated molecular patterns (PAMPs such as peptidoglycan, lipoteichoic acid, and lipoproteins and even intact S. aureus, are believed to act in conjunction with the staphylococcal superantigens (SSAg to activate the innate and adaptive immune system, respectively, and cause immunopathology. However, recent studies have shown that staphylococcal PAMPs could suppress inflammation by several mechanisms and protect from staphylococcal toxic shock syndrome, a life-threatening systemic disease caused by toxigenic S. aureus. Given the contradictory pro- and anti-inflammatory roles of staphylococcal PAMPs, we examined the effects of S. aureus-derived molecular patterns on immune responses driven by SSAg in vivo using HLA-DR3 and HLA-DQ8 transgenic mice. Our study showed that neither S. aureus-derived peptidoglycans (PGN, lipoteichoic acid (LTA, nor heat-killed Staphylococcus aureus (HKSA inhibited SSAg-induced T cell proliferation in vitro. They failed to antagonize the immunostimulatory effects of SSAg in vivo as determined by their inability to attenuate systemic cytokine/chemokine response and reduce SSAg-induced T cell expansion. These staphylococcal PAMPs also failed to protect HLA-DR3 as well as HLA-DQ8 transgenic mice from either SSAg-induced toxic shock or pneumonia induced by a SSAg-producing strain of S. aureus.

  2. Inducible Clindamycin Resistant Staphylococcus aureus in Iran: A Systematic Review and Meta-analysis

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    Ahmadreza Zarifian

    2015-11-01

    Full Text Available Introduction: Staphylococcus aureus is a prominent human pathogen. One of the drugs used in the treatment of staphylococcal infections (particularly infections of skin and soft tissue, is clindamycin. Resistance to clindamycin includes two types: inducible and constitutive. Routine laboratory methods of antibiotic susceptibility testing cannot detect the inducible type and D- test is required for its detection. The purpose of this systematic review was to determine the relative prevalence of this type of resistance in Iran.Methods: Search terms "inducible clindamycin resistant", "D-test", "Staphylococcus aureus" and "Iran" were used to find relevant articles in PubMed, Google Scholar and two Persian search engines. Also, the abstracts of the recent national microbiology congresses were checked.All studies used D-test to find iMLSB  (inducible macrolide, lincosamide and streptograminB resistance phenotype among clinical isolates (not nasal swabs of S. aureus, were included. In order to perform meta-analysis, we used “comprehensive meta-analysis” software (ver. 2.Results: In total, 9 articles and 8 abstracts related to the topic of the study were found. Random effects meta-analyses showed a pooled estimate for percentage of iMLSB  phenotype among 2683 samples of S. aureus was about 10% (95% confidence interval: 0.07-0.12. Using the fixed effect model, the odds of positive iMLSB  in methicillin-resistant S. aureus was about 5 times more likely to occur in comparison with methicillin-susceptible S. aureus (95% CI: 3.49 to 7.76.Conclusion: Fortunately, the relative frequency of inducible resistance to clindamycin in our country is relatively low. However, we believe that D-test should be performed for all erythromicin-resistant  isolates  in  order  to  identify  inducible  resistance  to  clindamycin.Moreover, reevaluation of inducible reistance to clindamycin in forthcoming years is highly recommended.

  3. Toxin-induced necroptosis is a major mechanism of Staphylococcus aureus lung damage.

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    Kipyegon Kitur

    2015-04-01

    Full Text Available Staphylococcus aureus USA300 strains cause a highly inflammatory necrotizing pneumonia. The virulence of this strain has been attributed to its expression of multiple toxins that have diverse targets including ADAM10, NLRP3 and CD11b. We demonstrate that induction of necroptosis through RIP1/RIP3/MLKL signaling is a major consequence of S. aureus toxin production. Cytotoxicity could be prevented by inhibiting either RIP1 or MLKL signaling and S. aureus mutants lacking agr, hla or Hla pore formation, lukAB or psms were deficient in inducing cell death in human and murine immune cells. Toxin-associated pore formation was essential, as cell death was blocked by exogenous K+ or dextran. MLKL inhibition also blocked caspase-1 and IL-1β production, suggesting a link to the inflammasome. Rip3(-/- mice exhibited significantly improved staphylococcal clearance and retained an alveolar macrophage population with CD200R and CD206 markers in the setting of acute infection, suggesting increased susceptibility of these leukocytes to necroptosis. The importance of this anti-inflammatory signaling was indicated by the correlation between improved outcome and significantly decreased expression of KC, IL-6, TNF, IL-1α and IL-1β in infected mice. These findings indicate that toxin-induced necroptosis is a major cause of lung pathology in S. aureus pneumonia and suggest the possibility of targeting components of this signaling pathway as a therapeutic strategy.

  4. Inducible resistance to clindamycin in Staphylococcus aureus: validation of Vitek-2 against CLSI D-test.

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    Gardiner, B J; Grayson, M L; Wood, G M

    2013-02-01

    Inducible resistance to clindamycin in Staphylococcus aureus is common but not easily identified by routine testing, and can result in treatment failure if not detected. The gold standard method is the D-test described by the Clinical and Laboratory Standards Institute (CLSI). The Vitek-2 AST-P612 card contains an 'inducible clindamycin resistance' (ICR) test. We aimed to determine the accuracy of the Vitek-2 ICR test compared to the D-test. Isolates of erythromycin non-susceptible, clindamycin susceptible Staphylococcus aureus were identified. Routine antimicrobial susceptibility testing was performed using the Vitek-2 AST-P612 card, including the ICR test, and compared against the D-test. 217 isolates were obtained. All of the 191 isolates that were ICR positive were D-test positive. Of the 27 ICR negative isolates, 10 (37%) were D-test positive [9 methicillin-sensitive S. aureus (MSSA), 1 methicillin-resistant S. aureus (MRSA)]. This correlates with a specificity of 100%, sensitivity of 95%, positive predictive value of 100%, and negative predictive value of 72%. The ICR test is reliable in the presence of a positive result; however there is a false negative rate of approximately one in four. This will lead to susceptibility reporting errors, with potentially serious clinical implications. A negative ICR should be confirmed by CLSI D-test before reporting clindamycin as susceptible where the organism is not susceptible to erythromycin.

  5. Staphylococcus aureus Biofilms Induce Macrophage Dysfunction Through Leukocidin AB and Alpha-Toxin

    Science.gov (United States)

    Scherr, Tyler D.; Hanke, Mark L.; Huang, Ouwen; James, David B. A.; Horswill, Alexander R.; Bayles, Kenneth W.; Fey, Paul D.; Torres, Victor J.

    2015-01-01

    ABSTRACT The macrophage response to planktonic Staphylococcus aureus involves the induction of proinflammatory microbicidal activity. However, S. aureus biofilms can interfere with these responses in part by polarizing macrophages toward an anti-inflammatory profibrotic phenotype. Here we demonstrate that conditioned medium from mature S. aureus biofilms inhibited macrophage phagocytosis and induced cytotoxicity, suggesting the involvement of a secreted factor(s). Iterative testing found the active factor(s) to be proteinaceous and partially agr-dependent. Quantitative mass spectrometry identified alpha-toxin (Hla) and leukocidin AB (LukAB) as critical molecules secreted by S. aureus biofilms that inhibit murine macrophage phagocytosis and promote cytotoxicity. A role for Hla and LukAB was confirmed by using hla and lukAB mutants, and synergy between the two toxins was demonstrated with a lukAB hla double mutant and verified by complementation. Independent confirmation of the effects of Hla and LukAB on macrophage dysfunction was demonstrated by using an isogenic strain in which Hla was constitutively expressed, an Hla antibody to block toxin activity, and purified LukAB peptide. The importance of Hla and LukAB during S. aureus biofilm formation in vivo was assessed by using a murine orthopedic implant biofilm infection model in which the lukAB hla double mutant displayed significantly lower bacterial burdens and more macrophage infiltrates than each single mutant. Collectively, these findings reveal a critical synergistic role for Hla and LukAB in promoting macrophage dysfunction and facilitating S. aureus biofilm development in vivo. PMID:26307164

  6. Combination of Erythromycin and Curcumin Alleviates Staphylococcus aureus Induced Osteomyelitis in Rats

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    Zubin Zhou

    2017-08-01

    Full Text Available Osteomyelitis is commonly caused by Staphylococcus aureus. Both erythromycin and curcumin can suppress S. aureus growth, but their roles in osteomyelitis are barely studied. We aim to explore the activities of erythromycin and curcumin against chronical osteomyelitis induced by methicillin-resistant S. aureus (MRSA. Chronicle implant-induced osteomyelitis was established by MRSA infection in male Wistar rats. Four weeks after bacterial inoculation, rats received no treatment, erythromycin monotherapy, curcumin monotherapy, or erythromycin plus curcumin twice daily for 2 weeks. Bacterial levels, bone infection status, inflammatory signals and side effects were evaluated. Rats tolerated all treatments well, with no death or side effects such as, diarrhea and weight loss. Two days after treatment completion, erythromycin monotherapy did not suppress bacterial growth and had no effect in bone infection, although it reduced serum pro-inflammatory cytokines tumor necrosis factor (TNF-α and interleukin (IL-6. Curcumin monotherapy slightly suppressed bacterial growth, alleviated bone infection and reduced TNF-α and IL-6. Erythromycin and curcumin combined treatment markedly suppressed bacterial growth, substantially alleviated bone infection and reduced TNF-α and IL-6. Combination of erythromycin and curcumin lead a much stronger efficiency against MRSA induced osteomyelitis in rats than monotherapy. Our study suggests that erythromycin and curcumin could be a new combination for treating MRSA induced osteomyelitis.

  7. Staphylococcus aureus-derived extracellular vesicles induce neutrophilic pulmonary inflammation via both Th1 and Th17 cell responses.

    Science.gov (United States)

    Kim, M-R; Hong, S-W; Choi, E-B; Lee, W-H; Kim, Y-S; Jeon, S G; Jang, M H; Gho, Y S; Kim, Y-K

    2012-10-01

    Recent evidence indicates that Staphylococcus aureus, one of the most important human pathogens, secretes vesicles into the extracellular milieu. To evaluate whether inhalation of S. aureus-derived extracellular vesicles (EV) is causally related to the pathogenesis of inflammatory pulmonary diseases. Staphylococcus aureus EV were prepared by sequential ultrafiltration and ultracentrifugation. The innate immune response was evaluated in vitro after the application of EV to airway epithelial cells and alveolar macrophages. In vivo innate and adaptive immune responses were evaluated after airway exposure to EV. Adjuvant effects of EV on the development of hypersensitivity to inhaled allergens were also evaluated after airway sensitization with S. aureus EV and ovalbumin (OVA). Staphylococcus aureus and S. aureus EV were detected in house dust. Alveolar macrophages produced both tumor necrosis α (TNF-α) and interleukin 6 (IL-6) after in vitro stimulation with S. aureus EV, whereas airway epithelial cells produced only IL-6. Repeated airway exposure to S. aureus EV induced both Th1 and Th17 cell responses and neutrophilic pulmonary inflammation, mainly via a Toll-like receptor 2 (TLR2)-dependent mechanism. In terms of adjuvant effects, airway sensitization with S. aureus EV and OVA resulted in neutrophilic pulmonary inflammation after OVA challenge alone. This phenotype was partly reversed by the absence of interferon γ (IFN-γ) or IL-17. Staphylococcus aureus EV can induce Th1 and Th17 neutrophilic pulmonary inflammation, mainly in a TLR2-dependent manner. Additionally, S. aureus EV enhance the development of airway hypersensitivity to inhaled allergens. © 2012 John Wiley & Sons A/S.

  8. Ability of Candida albicans Mutants To Induce Staphylococcus aureus Vancomycin Resistance during Polymicrobial Biofilm Formation▿

    Science.gov (United States)

    Harriott, Melphine M.; Noverr, Mairi C.

    2010-01-01

    Candida albicans and Staphylococcus aureus form vigorous polymicrobial biofilms in serum, which may serve as the source of coinfection in patients. More importantly, S. aureus is highly resistant to vancomycin during polymicrobial biofilm formation, with no decreases in bacterial viability observed with up to 1,600 μg/ml drug. In these mixed-species biofilms, S. aureus preferentially associates with C. albicans hyphae, which express a variety of unique adhesins. We tested C. albicans mutants deficient in transcriptional regulators of morphogenesis (CPH1 and EFG1) and biofilm formation (BCR1) to investigate the role of hyphae in mediating polymicrobial biofilm formation. These mutants also have reduced expression of hypha-specific adhesins. The ability to form polymicrobial biofilms correlated with the ability to form hyphae in these mutants. However, only mutants that could adhere to the abiotic surface could induce S. aureus vancomycin resistance, regardless of the presence of hyphae. In examining factors that may mediate interspecies adhesion, we found that the C. albicans ALS family of adhesins (Als1 to Als7 and Als9) was not involved, and neither was the hypha-specific adhesin Hwp1. Therefore, polymicrobial biofilm formation and subsequent antibiotic resistance is a multifactorial process that may require a unique combination of fungal and/or bacterial adhesins. PMID:20566760

  9. Apoptosis induced by Staphylococcus aureus in human monocytic ...

    African Journals Online (AJOL)

    Administrator

    2011-05-23

    May 23, 2011 ... Unfortunately, the cellular and molecular mechanisms responsible for this phenomenon are still poorly understood. The present study .... An annexin V apoptosis detection kit was purchased from RD Systems ..... Helicobacter pylori heat-shock protein 60 induces interleukin-8 via a Toll-like receptor (TLR)2 ...

  10. Sepsis Induced by Staphylococcus aureus: Participation of Biomarkers in a Murine Model

    Science.gov (United States)

    de Oliveira, Thiago Henrique Caldeira; Amorin, Aline Teixeira; Rezende, Izadora Souza; Barbosa, Maysa Santos; Martins, Hellen Braga; Brito, Anne Karoline Pereira; Andrade, Ewerton Ferraz; Gonçalves, Gleisy Kelly Neves; Campos, Guilherme Barreto; Silva, Robson Amaro Augusto; Timenetsky, Jorge; Marques, Lucas Miranda

    2015-01-01

    Background This study aimed to evaluate the role of biomarkers in the pathophysiological process induced by a Staphylococcus aureus strain obtained in a hospital environment. For this, we intraperitoneally inoculated groups of male BALB/c mice with S. aureus, using a clinical isolate (CI) of S. aureus. Material/Methods Mice were divided into groups according to time of euthanasia (24, 48, 72, 96, 120, 144, and 168 hours of infection). After being euthanized, blood samples were collected for quantification of microorganisms and leukocytes, as well as measurement of biomarkers of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), C-reactive protein (CRP), and Procalcitonin (PCT) by ELISA. Heart, kidneys, and lungs were removed for histopathological analysis, assessment of biomarkers of tissue expression by RT-PCR (polymerase chain reaction with reverse transcriptase), and quantification of microorganisms by real-time quantitative PCR (real-time PCR). Results The animals infected at between 120 hours and 168 hours had the highest blood levels of S. aureus. We observed that infection promoted increases in the levels of circulating neutrophils and monocytes. However, there was a reduction of circulating neutrophils and monocytes after 96 hours of infection. The infected mice also had increased levels of blood lymphocytes. In this model of infection with S. aureus, IL-6, CRP, and PCT demonstrated greater fidelity as markers of infection, since serum levels were elevated and lowered along with the number of circulating neutrophils and monocytes after resolution of the infection. The lungs showed hyperemia, with enlargement of the alveolar septa. On the other hand, infection with S. aureus did not promote visible change in histological tissue in the heart and kidneys. Conclusions In this model of infection with S. aureus, IL-6, CRP, and PCT demonstrated greater fidelity as markers of infection, since serum levels were elevated and lowered along with the number of

  11. Staphylococcus aureus-induced G2/M phase transition delay in host epithelial cells increases bacterial infective efficiency.

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    Ludmila Alekseeva

    Full Text Available Staphylococcus aureus is a highly versatile, opportunistic pathogen and the etiological agent of a wide range of infections in humans and warm-blooded animals. The epithelial surface is its principal site of colonization and infection. In this work, we investigated the cytopathic effect of S. aureus strains from human and animal origins and their ability to affect the host cell cycle in human HeLa and bovine MAC-T epithelial cell lines. S. aureus invasion slowed down cell proliferation and induced a cytopathic effect, resulting in the enlargement of host cells. A dramatic decrease in the number of mitotic cells was observed in the infected cultures. Flow cytometry analysis revealed an S. aureus-induced delay in the G2/M phase transition in synchronous HeLa cells. This delay required the presence of live S. aureus since the addition of the heat-killed bacteria did not alter the cell cycle. The results of Western blot experiments showed that the G2/M transition delay was associated with the accumulation of inactive cyclin-dependent kinase Cdk1, a key inducer of mitosis entry, and with the accumulation of unphosphorylated histone H3, which was correlated with a reduction of the mitotic cell number. Analysis of S. aureus proliferation in asynchronous, G1- and G2-phase-enriched HeLa cells showed that the G2 phase was preferential for bacterial infective efficiency, suggesting that the G2 phase delay may be used by S. aureus for propagation within the host. Taken together, our results divulge the potential of S. aureus in the subversion of key cellular processes such as cell cycle progression, and shed light on the biological significance of S. aureus-induced host cell cycle alteration.

  12. A3R Phage and Staphylococcus aureus Lysate Do Not Induce Neutrophil Degranulation

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    Jan Borysowski

    2017-02-01

    Full Text Available The objective of this study was to evaluate the effects of A3R phage and Staphylococcus aureus lysate obtained after phage infection on neutrophil degranulation. The exocytosis of primary and secondary granules from neutrophils was investigated in vitro in whole blood specimens by flow cytometry based on the expression of specific markers of exocytosis (CD63 for primary granules and CD66b for secondary granules. We found that both A3R and S. aureus lysate had no significant effect on the exocytosis of primary and secondary granules. These data suggest that neither A3R virions nor any products of phage-induced lysis of S. aureus are likely to induce neutrophil degranulation in patients who are treated with phage preparations. Since neutrophil granules contain some potentially toxic proteins, our results provide an important argument for the safety of phage therapy. Moreover, these data indicate that the induction of neutrophil degranulation is not likely to contribute to antibacterial effects of phages.

  13. A Surfactant-Induced Functional Modulation of a Global Virulence Regulator from Staphylococcus aureus.

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    Sukhendu Mandal

    Full Text Available Triton X-100 (TX-100, a useful non-ionic surfactant, reduced the methicillin resistance in Staphylococcus aureus significantly. Many S. aureus proteins were expressed in the presence of TX-100. SarA, one of the TX-100-induced proteins, acts as a global virulence regulator in S. aureus. To understand the effects of TX-100 on the structure, and function of SarA, a recombinant S. aureus SarA (rSarA and its derivative (C9W have been investigated in the presence of varying concentrations of this surfactant using various probes. Our data have revealed that both rSarA and C9W bind to the cognate DNA with nearly similar affinity in the absence of TX-100. Interestingly, their DNA binding activities have been significantly increased in the presence of pre-micellar concentration of TX-100. The increase of TX-100 concentrations to micellar or post-micellar concentration did not greatly enhance their activities further. TX-100 molecules have altered the secondary and tertiary structures of both proteins to some extents. Size of the rSarA-TX-100 complex appears to be intermediate to those of rSarA and TX-100. Additional analyses show a relatively moderate interaction between C9W and TX-100. Binding of TX-100 to C9W has, however, occurred by a cooperative pathway particularly at micellar and higher concentrations of this surfactant. Taken together, TX-100-induced structural alteration of rSarA and C9W might be responsible for their increased DNA binding activity. As TX-100 has stabilized the somewhat weaker SarA-DNA complex effectively, it could be used to study its structure in the future.

  14. MRI visualization of Staphyloccocus aureus-induced infective endocarditis in mice.

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    Janine Ring

    Full Text Available Infective endocarditis (IE is a severe and often fatal disease, lacking a fast and reliable diagnostic procedure. The purpose of this study was to establish a mouse model of Staphylococcus aureus-induced IE and to develop a MRI technology to characterize and diagnose IE. To establish the mouse model of hematogenous IE, aortic valve damage was induced by placing a permanent catheter into right carotid artery. 24 h after surgery, mice were injected intravenously with either iron particle-labeled or unlabeled S. aureus (strain 6850. To distinguish the effect of IE from mere tissue injury or recruited macrophages, subgroups of mice received sham surgery prior to infection (n = 17, received surgery without infection (n = 8, or obtained additionally injection of free iron particles to label macrophages (n = 17. Cardiac MRI was performed 48 h after surgery using a self-gated ultra-short echo time (UTE sequence (TR/TE, 5/0.31 ms; in-plane/slice, 0.125/1 mm; duration, 12∶08 min to obtain high-resolution, artifact-free cinematographic images of the valves. After MRI, valves were either homogenized and plated on blood agar plates for determination of bacterial titers, or sectioned and stained for histology. In the animal model, both severity of the disease and mortality increased with bacterial numbers. Infection with 105 S. aureus bacteria reliably caused endocarditis with vegetations on the valves. Cinematographic UTE MRI visualised the aortic valve over the cardiac cycle and allowed for detection of bacterial vegetations, while mere tissue trauma or labeled macrophages were not detected. Iron labeling of S. aureus was not required for detection. MRI results were consistent with histology and microbial assessment. These data showed that S. aureus-induced IE in mice can be detected by MRI. The established mouse model allows for investigation of the pathophysiology of IE, testing of novel drugs and may serve for the development of a clinical

  15. Phenotypic detection of inducible clindamycin resistance among Staphylococcus aureus isolates by using the lower limit of recommended inter-disk distance

    OpenAIRE

    Ajantha G; Kulkarni Raghavendra; Shetty Jeevan; Shubhada C; Jain Pavithra

    2008-01-01

    Context: Clindamycin is one of the important alternative antibiotics in the therapy of Staphylococcus aureus, particularly in methicillin-resistant S. aureus (MRSA) infections. Inducible clindamycin resistance (iMLS B - inducible Macrolide-Lincosamide-Streptogramin B resistance) is a critical factor in antimicrobial susceptibility testing. Aims: To know the rate of inducible clindamycin resistance among clinical isolates of Staphylococcus aureus in our hospital by Disk approximation test ...

  16. Neutralization of MMP-2 protects Staphylococcus aureus infection induced septic arthritis in mice and regulates the levels of cytokines.

    Science.gov (United States)

    Sultana, Sahin; Adhikary, Rana; Nandi, Ajeya; Bishayi, Biswadev

    2016-10-01

    Matrix metalloproteinases (MMPs) are crucial players in Staphylococcus aureus mediated synovial tissue destruction in the pathogenesis of septic arthritis. Bacterial insult increases proteolytic matrix fragments by activated chondrocytes and synovial fibroblasts leading to induction of matrix metalloproteinases. Tissue destruction via MMPs induced by bacterial products, necrotic tissues and proinflammatory cytokines have been reported. Cytokines like TNF-α, IL-1β released from host cells in response to S. aureus infection promote cartilage degradation by stimulating the production of MMPs. Antibiotic treatment can eradicate invading bacteria but elevated levels of cytokines and cytokines induced MMPs activation lead to progressive and devastating bone and cartilage destruction even after bacterial clearance. Like other MMPs, MMP-2 also contributes to extracellular matrix degradation in different types of arthritis. Release of certain pro inflammatory cytokines can also be regulated by MMP-2 activation leading to further tissue destruction. The role of MMP-2 in the pathogenesis of S. aureus infection induced septic arthritis and its influence on cytokines regulation needs further investigation. Whether neutralization of MMP-2 provides protection against Staphylococcus aureus infection induced septic arthritis in mice is an obvious question. Here we reported that neutralization of MMP-2 during S. aureus infection induced septic arthritis might be beneficial for preventing infection induced extracellular matrix destruction thereby decreasing bacterial burden in synovial tissues and regulating inflammatory cytokines in arthritic mice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Exacerbation of cigarette smoke-induced pulmonary inflammation by Staphylococcus aureus Enterotoxin B in mice

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    Brusselle Guy G

    2011-05-01

    Full Text Available Abstract Background Cigarette smoke (CS is a major risk factor for the development of COPD. CS exposure is associated with an increased risk of bacterial colonization and respiratory tract infection, because of suppressed antibacterial activities of the immune system and delayed clearance of microbial agents from the lungs. Colonization with Staphylococcus aureus results in release of virulent enterotoxins, with superantigen activity which causes T cell activation. Objective To study the effect of Staphylococcus aureus enterotoxin B (SEB on CS-induced inflammation, in a mouse model of COPD. Methods C57/Bl6 mice were exposed to CS or air for 4 weeks (5 cigarettes/exposure, 4x/day, 5 days/week. Endonasal SEB (10 μg/ml or saline was concomitantly applied starting from week 3, on alternate days. 24 h after the last CS and SEB exposure, mice were sacrificed and bronchoalveolar lavage (BAL fluid and lung tissue were collected. Results Combined exposure to CS and SEB resulted in a raised number of lymphocytes and neutrophils in BAL, as well as increased numbers of CD8+ T lymphocytes and granulocytes in lung tissue, compared to sole CS or SEB exposure. Moreover, concomitant CS/SEB exposure induced both IL-13 mRNA expression in lungs and goblet cell hyperplasia in the airway wall. In addition, combined CS/SEB exposure stimulated the formation of dense, organized aggregates of B- and T- lymphocytes in lungs, as well as significant higher CXCL-13 (protein, mRNA and CCL19 (mRNA levels in lungs. Conclusions Combined CS and SEB exposure aggravates CS-induced inflammation in mice, suggesting that Staphylococcus aureus could influence the pathogenesis of COPD.

  18. β-lactam antibiotic-induced release of lipoteichoic acid from Staphylococcus aureus leads to activation of neutrophil granulocytes

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    Hartung Thomas

    2006-06-01

    Full Text Available Abstract Background Polymorphonuclear neutrophil granulocytes (PMN are phagocytes of the first line of antimicrobial defense. Previously we demonstrated that lipoteichoic acid (LTA from Staphylococcus aureus (S. aureus directly activates neutrophil granulocytes. Others have reported that exposure of S. aureus to β-lactam antibiotics leads to LTA release. In the present study we addressed the question whether exposure of S. aureus to β-lactam antibiotics or antibiotics of other groups results in the generation of PMN-stimulating activity and whether this activity can be attributed to LTA. Methods S. aureus were exposed to flucloxacillin, a β-lactam antibiotic or to the protein synthesis-inhibitors erythromycin and gentamicin, or to ciprofloxacin, a gyrase inhibitor. Supernatants of the antibiotic-treated bacteria were assayed for their LTA content and for their effect on PMN functions. Results We observed that exposure of S. aureus to flucloxacillin and, to a lesser degree to ciprofloxacin, but not to erythromycin or gentamicin led to LTA release. Co-incubation of neutrophil granulocytes with LTA-containing supernatants led to PMN activation as assed by morphological changes, release of IL-8, delay of spontaneous apoptosis and enhanced phagocytic activity. Depletion of LTA from the supernatants markedly reduced their PMN-activating capacity. Conclusion The findings suggest that, via the activation of PMN, antibiotic-induced LTA release from S. aureus leads to enhanced antimicrobial activity of the innate immune defense mechanisms.

  19. Steady-state hydrogen peroxide induces glycolysis in Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Deng, Xin; Liang, Haihua; Ulanovskaya, Olesya A; Ji, Quanjiang; Zhou, Tianhong; Sun, Fei; Lu, Zhike; Hutchison, Alan L; Lan, Lefu; Wu, Min; Cravatt, Benjamin F; He, Chuan

    2014-07-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from human pathogens Staphylococcus aureus and Pseudomonas aeruginosa can be readily inhibited by reactive oxygen species (ROS)-mediated direct oxidation of their catalytic active cysteines. Because of the rapid degradation of H2O2 by bacterial catalase, only steady-state but not one-dose treatment with H2O2 rapidly induces glycolysis and the pentose phosphate pathway (PPP). We conducted transcriptome sequencing (RNA-seq) analyses to globally profile the bacterial transcriptomes in response to a steady level of H2O2, which revealed profound transcriptional changes, including the induced expression of glycolytic genes in both bacteria. Our results revealed that the inactivation of GAPDH by H2O2 induces metabolic levels of glycolysis and the PPP; the elevated levels of fructose 1,6-biphosphate (FBP) and 2-keto-3-deoxy-6-phosphogluconate (KDPG) lead to dissociation of their corresponding glycolytic repressors (GapR and HexR, respectively) from their cognate promoters, thus resulting in derepression of the glycolytic genes to overcome H2O2-stalled glycolysis in S. aureus and P. aeruginosa, respectively. Both GapR and HexR may directly sense oxidative stresses, such as menadione. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  20. Haemolysis induced by α-toxin from Staphylococcus aureus requires P2X receptor activation

    DEFF Research Database (Denmark)

    Skals, Marianne Gerberg; Leipziger, Jens Georg; Prætorius, Helle

    2011-01-01

    -forming bacterial toxins. In this context, it is essential to know whether this is specific to HlyA-induced cell damage or if other bacterial pore-forming toxins involve purinergic signals to orchestrate haemolysis. Here, we investigate if the haemolysis produced by α-toxin from Staphylococcus aureus involves P2...... receptor activation. We observed that α-toxin-induced haemolysis is completely blocked by the unselective P2 receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid. Moreover, several selective blockers of P2X1 and P2X7 ionotropic receptors abolished haemolysis in murine and equine...... erythrocytes. Inhibitors of pannexin channels partially reduced the α-toxin induced lysis. Thus, we conclude that α-toxin, similar to HlyA from E. coli produces cell damage by specific activation of a purinergic signalling cascade. These data indicate that pore-forming toxins in general require purinergic...

  1. Inducible clindamycin and methicillin resistant Staphylococcus aureus in a tertiary care hospital, Kathmandu, Nepal.

    Science.gov (United States)

    Adhikari, R P; Shrestha, S; Barakoti, A; Amatya, R

    2017-07-11

    Staphylococcus aureus, an important nosocomial pathogen, is frequently associated with infections in human. The management of the infections by it especially methicillin resistant ones is often difficult because methicillin resistant S. aureus is usually resistant to multiple antibiotics. Macrolide-lincosamide streptogramin B family of antibiotics is commonly used to treat such infections as an alternative to vancomycin. This study was conducted over the period of one and half year from November 2013-April 2015 in Microbiology laboratory of Nepal Medical College and Teaching Hospital, Kathmandu, Nepal to find the incidence of different phenotypes of MLS B resistance among S. aureus from clinical samples and their association with methicillin resistance. Two hundred seventy isolates of S. aureus were included in the study. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by erythromycin and clindamycin disc approximation test (D-test). Of the 270 clinical isolates of S. aureus, 25.1% (68/270) were MRSA. Erythromycin and clindamycin resistance was seen in 54.4% (147/270) and 41.8% (113/270) isolates respectively. Resistance to erythromycin and clindamycin were higher in MRSA as compared to MSSA (erythromycin-resistance: 88.2% Vs 39.1% and clindamycin-resistance: 79.4% Vs 41.8%). The overall prevalence of i MLS B and c MLS B phenotype was 11.48% (31/270) and 29.25% (79/270) respectively. Both i MLS B and c MLS B phenotypes predominated in MRSA strains. Detection rate of MRSA in our study shows the necessity to improve in healthcare practices and to formulate new policy for the control of MRSA infections. Clindamycin resistance in the form of i MLS B and c MLS B especially among MRSA emphasizes the need of D-test to be performed routinely in our set up while using clindamycin as an alternative choice to anti-staphylococcal antibiotics like vancomycin and linezolid in the treatment of staphylococcal infections.

  2. alpha-Toxin is a mediator of Staphylococcus aureus-induced cell death and activates caspases via the intrinsic death pathway independently of death receptor signaling

    NARCIS (Netherlands)

    Bantel, H; Sinha, B; Domschke, W; Peters, Georg; Schulze-Osthoff, K; Jänicke, R U

    2001-01-01

    Infections with Staphylococcus aureus, a common inducer of septic and toxic shock, often result in tissue damage and death of various cell types. Although S. aureus was suggested to induce apoptosis, the underlying signal transduction pathways remained elusive. We show that caspase activation and

  3. Vaccine composition formulated with a novel TLR7-dependent adjuvant induces high and broad protection against Staphylococcus aureus

    Science.gov (United States)

    Bagnoli, Fabio; Fontana, Maria Rita; Soldaini, Elisabetta; Mishra, Ravi P. N.; Fiaschi, Luigi; Cartocci, Elena; Nardi-Dei, Vincenzo; Ruggiero, Paolo; Nosari, Sarah; De Falco, Maria Grazia; Lofano, Giuseppe; Marchi, Sara; Galletti, Bruno; Mariotti, Paolo; Bacconi, Marta; Torre, Antonina; Maccari, Silvia; Scarselli, Maria; Rinaudo, C. Daniela; Inoshima, Naoko; Savino, Silvana; Mori, Elena; Rossi-Paccani, Silvia; Baudner, Barbara; Pallaoro, Michele; Swennen, Erwin; Petracca, Roberto; Brettoni, Cecilia; Liberatori, Sabrina; Norais, Nathalie; Monaci, Elisabetta; Bubeck Wardenburg, Juliane; Schneewind, Olaf; O’Hagan, Derek T.; Valiante, Nicholas M.; Bensi, Giuliano; Bertholet, Sylvie; De Gregorio, Ennio; Rappuoli, Rino; Grandi, Guido

    2015-01-01

    Both active and passive immunization strategies against Staphylococcus aureus have thus far failed to show efficacy in humans. With the attempt to develop an effective S. aureus vaccine, we selected five conserved antigens known to have different roles in S. aureus pathogenesis. They include the secreted factors α-hemolysin (Hla), ess extracellular A (EsxA), and ess extracellular B (EsxB) and the two surface proteins ferric hydroxamate uptake D2 and conserved staphylococcal antigen 1A. The combined vaccine antigens formulated with aluminum hydroxide induced antibodies with opsonophagocytic and functional activities and provided consistent protection in four mouse models when challenged with a panel of epidemiologically relevant S. aureus strains. The importance of antibodies in protection was demonstrated by passive transfer experiments. Furthermore, when formulated with a toll-like receptor 7-dependent (TLR7) agonist recently designed and developed in our laboratories (SMIP.7–10) adsorbed to alum, the five antigens provided close to 100% protection against four different staphylococcal strains. The new formulation induced not only high antibody titers but also a Th1 skewed immune response as judged by antibody isotype and cytokine profiles. In addition, low frequencies of IL-17–secreting T cells were also observed. Altogether, our data demonstrate that the rational selection of mixtures of conserved antigens combined with Th1/Th17 adjuvants can lead to promising vaccine formulations against S. aureus. PMID:25775551

  4. An important role of α-hemolysin in extracellular vesicles on the development of atopic dermatitis induced by Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Sung-Wook Hong

    Full Text Available Skin barrier disruption and dermal inflammation are key phenotypes of atopic dermatitis (AD. Staphylococcus aureus secretes extracellular vesicles (EVs, which are involved in AD pathogenesis. Here, we evaluated the role of EVs-associated α-hemolysin derived from S. aureus in AD pathogenesis. α-hemolysin production from S. aureus was detected using western blot analyses. The cytotoxic activity of α-hemolysin on HaCaT keratinocytes was evaluated by measuring cell viability after treating cells with soluble and EVs-associated α-hemolysin. To determine the type of cell death, HaCaT keratinocytes were stained with annexin V and 7-AAD. The in vivo effects of α-hemolysin were evaluated by application of soluble and EV-associated α-hemolysin on the mouse skin. The present study showed that increased α-hemolysin was produced by S. aureus colonized on AD patients compared to healthy subjects. α-hemolysin production was also related to AD severity. In addition, EV-associated α-hemolysin was more cytotoxic to HaCaT keratinocytes than soluble α-hemolysin, and α-hemolysin-negative EVs did not induce keratinocyte death. EV-associated α-hemolysin induced necrosis, but soluble α-hemolysin induced apoptosis of keratinocytes. In vivo, skin barrier disruption and epidermal hyperplasia were induced by soluble and EV-associated α-hemolysin. However, AD-like dermal inflammation was only caused by EV-associated α-hemolysin. Moreover, neither skin barrier disruption nor AD-like skin inflammation was induced by α-hemolysin-negative EVs. Taken together, α-Hemolysin secreted from S. aureus, particularly the EV-associated form, induces both skin barrier disruption and AD-like skin inflammation, suggesting that EV-associated α-hemolysin is a novel diagnostic and therapeutic target for the control of AD.

  5. An important role of α-hemolysin in extracellular vesicles on the development of atopic dermatitis induced by Staphylococcus aureus.

    Science.gov (United States)

    Hong, Sung-Wook; Choi, Eun-Byul; Min, Taek-Ki; Kim, Ji-Hyun; Kim, Min-Hye; Jeon, Seong Gyu; Lee, Byung-Jae; Gho, Yong Song; Jee, Young-Koo; Pyun, Bok-Yang; Kim, Yoon-Keun

    2014-01-01

    Skin barrier disruption and dermal inflammation are key phenotypes of atopic dermatitis (AD). Staphylococcus aureus secretes extracellular vesicles (EVs), which are involved in AD pathogenesis. Here, we evaluated the role of EVs-associated α-hemolysin derived from S. aureus in AD pathogenesis. α-hemolysin production from S. aureus was detected using western blot analyses. The cytotoxic activity of α-hemolysin on HaCaT keratinocytes was evaluated by measuring cell viability after treating cells with soluble and EVs-associated α-hemolysin. To determine the type of cell death, HaCaT keratinocytes were stained with annexin V and 7-AAD. The in vivo effects of α-hemolysin were evaluated by application of soluble and EV-associated α-hemolysin on the mouse skin. The present study showed that increased α-hemolysin was produced by S. aureus colonized on AD patients compared to healthy subjects. α-hemolysin production was also related to AD severity. In addition, EV-associated α-hemolysin was more cytotoxic to HaCaT keratinocytes than soluble α-hemolysin, and α-hemolysin-negative EVs did not induce keratinocyte death. EV-associated α-hemolysin induced necrosis, but soluble α-hemolysin induced apoptosis of keratinocytes. In vivo, skin barrier disruption and epidermal hyperplasia were induced by soluble and EV-associated α-hemolysin. However, AD-like dermal inflammation was only caused by EV-associated α-hemolysin. Moreover, neither skin barrier disruption nor AD-like skin inflammation was induced by α-hemolysin-negative EVs. Taken together, α-Hemolysin secreted from S. aureus, particularly the EV-associated form, induces both skin barrier disruption and AD-like skin inflammation, suggesting that EV-associated α-hemolysin is a novel diagnostic and therapeutic target for the control of AD.

  6. Aspidin BB, a phloroglucinol derivative, exerts its antibacterial activity against Staphylococcus aureus by inducing the generation of reactive oxygen species.

    Science.gov (United States)

    Li, Na; Gao, Chang; Peng, Xiao; Wang, Wei; Luo, Meng; Fu, Yu-jie; Zu, Yuan-gang

    2014-05-01

    Aspidin BB, a phloroglucinol derivative extracted from Dryopteris fragrans (L.) Schott, has been previously reported to exert high biological activities. In the present study, antibacterial activities and mechanisms of aspidin BB against Staphylococcus aureus were investigated. Aspidin BB exhibited strong antibacterial activity against standard and three clinical S. aureus, with minimal inhibition concentration (MIC) values ranging from 15.63 μg/mL to 62.5 μg/mL. After treatment with aspidin BB for 72 h using the MTT assay, the IC50 value was 48.14 μM (22.11 μg/mL). The time-kill assay indicated that aspidin BB could kill S. aureus completely at 2 MIC (MBC) within 4 h. Aspidin BB was capable to induce an increase in NADPH oxidase activity from 4.03 U/mg to 7.48 U/mg when the concentrations were increased from 1/2 MIC to 4 MIC. Simultaneously, aspidin BB attenuated antioxidant defense by decreasing superoxide dismutase (SOD) activity and glutathione (GSH) levels. The level of reactive oxygen species (ROS) was apparently elevated when measuring OD575. This phenomenon was blocked by pretreatment of S. aureus with the antioxidant compound catalase (200 U/mL) and the survival rate of S. aureus increased from 3.95% to 73.04%. These results showed that ROS was indeed an important mediator in the antibacterial action of aspidin BB. In addition, aspidin-BB-induced peroxidation of membranes, DNA damage and protein degradation of S. aureus were all verified in a dose-dependent manner. In conclusion, aspidin BB induced generation of ROS by activating NADPH oxidase activity and inhibiting SOD activity and GSH levels, damaging the membrane, DNA and proteins and finally led to cell death. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  7. Low levels of β-lactam antibiotics induce extracellular DNA release and biofilm formation in Staphylococcus aureus.

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    Kaplan, Jeffrey B; Izano, Era A; Gopal, Prerna; Karwacki, Michael T; Kim, Sangho; Bose, Jeffrey L; Bayles, Kenneth W; Horswill, Alexander R

    2012-01-01

    Subminimal inhibitory concentrations of antibiotics have been shown to induce bacterial biofilm formation. Few studies have investigated antibiotic-induced biofilm formation in Staphylococcus aureus, an important human pathogen. Our goal was to measure S. aureus biofilm formation in the presence of low levels of β-lactam antibiotics. Fifteen phylogenetically diverse methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains were employed. Methicillin, ampicillin, amoxicillin, and cloxacillin were added to cultures at concentrations ranging from 0× to 1× MIC. Biofilm formation was measured in 96-well microtiter plates using a crystal violet binding assay. Autoaggregation was measured using a visual test tube settling assay. Extracellular DNA was quantitated using agarose gel electrophoresis. All four antibiotics induced biofilm formation in some strains. The amount of biofilm induction was as high as 10-fold and was inversely proportional to the amount of biofilm produced by the strain in the absence of antibiotics. MRSA strains of lineages USA300, USA400, and USA500 exhibited the highest levels of methicillin-induced biofilm induction. Biofilm formation induced by low-level methicillin was inhibited by DNase. Low-level methicillin also induced DNase-sensitive autoaggregation and extracellular DNA release. The biofilm induction phenotype was absent in a strain deficient in autolysin (atl). Our findings demonstrate that subminimal inhibitory concentrations of β-lactam antibiotics significantly induce autolysin-dependent extracellular DNA release and biofilm formation in some strains of S. aureus. The widespread use of antibiotics as growth promoters in agriculture may expose bacteria to low levels of the drugs. The aim of this study was to investigate the effects of low levels of antibiotics on bacterial autoaggregation and biofilm formation, two processes that have been shown to foster genetic exchange and antibiotic

  8. Staphylococcus aureus-induced clotting of plasma is an immune evasion mechanism for persistence within the fibrin network.

    Science.gov (United States)

    Loof, Torsten G; Goldmann, Oliver; Naudin, Clément; Mörgelin, Matthias; Neumann, Yvonne; Pils, Marina C; Foster, Simon J; Medina, Eva; Herwald, Heiko

    2015-03-01

    Recent work has shown that coagulation and innate immunity are tightly interwoven host responses that help eradicate an invading pathogen. Some bacterial species, including Staphylococcus aureus, secrete pro-coagulant factors that, in turn, can modulate these immune reactions. Such mechanisms may not only protect the micro-organism from a lethal attack, but also promote bacterial proliferation and the establishment of infection. Our data showed that coagulase-positive S. aureus bacteria promoted clotting of plasma which was not seen when a coagulase-deficient mutant strain was used. Furthermore, in vitro studies showed that this ability constituted a mechanism that supported the aggregation, survival and persistence of the micro-organism within the fibrin network. These findings were also confirmed when agglutination and persistence of coagulase-positive S. aureus bacteria at the local focus of infection were studied in a subcutaneous murine infection model. In contrast, the coagulase-deficient S. aureus strain which was not able to induce clotting failed to aggregate and to persist in vivo. In conclusion, our data suggested that coagulase-positive S. aureus have evolved mechanisms that prevent their elimination within a fibrin clot. © 2015 The Authors.

  9. 5-Aminolevulinic acid induced photodynamic inactivation on Staphylococcus aureus and Pseudomonas aeruginosa

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    Chien-Ming Hsieh

    2014-09-01

    Full Text Available The aim of the present study was to develop a simple and fast screening technique to directly evaluate the bactericidal effects of 5-aminolevulinic acid (ALA-mediated photodynamic inactivation (PDI and to determine the optimal antibacterial conditions of ALA concentrations and the total dosage of light in vitro. The effects of PDI on Staphylococcus aureus and Pseudomonas aeruginosa in the presence of various concentrations of ALA (1.0 mM, 2.5 mM, 5.0 mM, 10.0 mM were examined. All bacterial strains were exponentially grown in the culture medium at room temperature in the dark for 60 minutes and subsequently irradiated with 630 ± 5 nm using a light-emitting diode (LED red light device for accumulating the light doses up to 216 J/cm2. Both bacterial species were susceptible to the ALA-induced PDI. Photosensitization using 1.0 mM ALA with 162 J/cm2 light dose was able to completely reduce the viable counts of S. aureus. A significant decrease in the bacterial viabilities was observed for P. aeruginosa, where 5.0 mM ALA was photosensitized by accumulating the light dose of 162 J/cm2. We demonstrated that the use of microplate-based assays—by measuring the apparent optical density of bacterial colonies at 595 nm—was able to provide a simple and reliable approach for quickly choosing the parameters of ALA-mediated PDI in the cell suspensions.

  10. Staphylococcus aureus and Salmonella enterica Serovar Dublin Induce Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Expression by Normal Mouse and Human Osteoblasts

    Science.gov (United States)

    Alexander, Emily H.; Bento, Jennifer L.; Hughes, Francis M.; Marriott, Ian; Hudson, Michael C.; Bost, Kenneth L.

    2001-01-01

    Staphylococcus aureus and Salmonella enterica serovar Dublin invade osteoblasts and are causative agents of human bone disease. In the present study, we examined the ability of S. aureus and Salmonella serovar Dublin to induce the production of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) by normal osteoblasts. Normal mouse and human osteoblasts were cocultured with S. aureus or Salmonella serovar Dublin at different multiplicities of infection. Following initial incubation and examination of TRAIL expression, extracellular bacteria were killed by the addition of media containing the antibiotic gentamicin. Lysates and conditioned media from osteoblast cultures were then collected at various times following invasion and analyzed. The results demonstrated that S. aureus and Salmonella serovar Dublin are potent inducers of TRAIL expression by osteoblasts. Mouse and human TRAIL mRNA expression was induced by bacterial infection and demonstrated a dose-dependent response. Analysis of kinetics suggested that TRAIL mRNA was induced within 30 min after exposure to bacteria and that its level of expression remained relatively constant over the time period examined. mRNA molecules encoding TRAIL receptors were constitutively expressed by osteoblasts. Furthermore, TRAIL protein was detected as early as 45 min and up to 24 h following infection. The quantity of TRAIL protein produced also increased in a dose-dependent manner. Collectively, these findings suggest a mechanism whereby bacterial pathogens mediate bone destruction via osteoblast apoptosis. PMID:11179330

  11. Protective effects of camel milk against pathogenicity induced by Escherichia coli and Staphylococcus aureus in Wistar rats.

    Science.gov (United States)

    Soliman, Mohamed Mohamed; Hassan, Magdy Yassin; Mostafa, Salama Abdel-Hafiz; Ali, Hussein Abdel-Maksoud; Saleh, Osama Moseilhy

    2015-12-01

    The aim of the present study was to investigate the protective effects of camel milk on hepatic pathogenicity induced by experimental infection with Escherichia (E. coli) and Staphylococcus aureus (S. aureus) in Wistar rats. The rats were divided into six groups: The control and camel milk groups received water and camel milk, respectively; two groups received camel milk for 2 weeks prior to intraperitoneal injection of either E. coli or S. aureus; and two groups were injected intraperitoneally with E. coli and S. aureus, respectively. All animals were maintained under observation for 7 days prior to biochemical and gene expression analyses. The rats treated with camel milk alone exhibited no changes in expression levels of glutamic‑pyruvate transaminase (GPT) or glutamic‑oxaloacetic transaminase (GOT), compared with the water‑treated group. The E. coli‑ and S. aureus‑injected rats exhibited a significant increase in oxidative stress, and prior treatment with camel milk normalized the observed changes in the expression levels of GPT, GOT and malondialdehyde (MDA). Treatment with camel milk decreased the total bacterial count in liver tissue samples obtained from the rats injected with E. coli and S. aureus. Camel milk administration increased the expression levels of glutathione‑S‑transferase and superoxide dismutase, which were downregulated following E. coli and S. aureus injection. In addition, camel milk downregulated the increased expression of interleukin‑6 and apoptosis‑associated genes. Of note, administration of camel milk alone increased the expression levels of the B cell lymphoma 2‑associated X protein and survivin anti‑apoptotic genes, and supplementation prior to the injection of E. coli and S. aureus induced further upregulation, In conclusion, camel milk exerted protective effects against E. coli and S. aureus pathogenicity, by modulating the extent of lipid peroxidation, together with the antioxidant defense

  12. Comparative effiacy of marine Streptomyces formulation versus ciproflxacin ophthalmic solution for treating Staphylococcus aureus-induced conjunctivitis in animal model

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    Femina Wahaab

    2016-03-01

    Full Text Available Objective: To report the efficacy of marine actinomycetes in controlling Staphylococcus aureus (S. aureus-induced conjunctivitis in experimental rabbit. Methods: The ethyl acetate extracts of the best isolates of actinomycetes from the soil samples of Rameswaram coastal regions, Tamil Nadu, India, were concentrated and re-constituted in buffer and used as actinomycetes ophthalmic suspension in this study. The anti-inflammatory efficacy of actinomycetes ophthalmic suspension was analysed in controlling S. aureusinduced conjunctivitis in rabbit in comparison with that of ciprofloxacin. Results: Among the four best isolates, the RAM25C4 isolate had the highest antimicrobial activity in the secondary screening. Shelf life studies indicated that the activity can be retained for 75 days when it was stored at 8 °C and the optimum temperature for storage was between –20°C and 30°C. The animal model studies indicated that there was a profound anti-conjunctivitis effect. The actinomycetes ophthalmic suspension had better activity than ciprofloxacin ophthalmic solution. Conclusions: This is the first time to report that Streptomyces bacillaris strain RAM25C4 has antimicrobial effect in controlling ophthalmic pathogen S. aureus under in vitro condition and the in vivo anti-inflammatory activity in controlling S. aureus-induced conjunctivitis.

  13. Puerarin Exerts an Antiinflammatory Effect by Inhibiting NF-kB and MAPK Activation in Staphylococcus aureus-Induced Mastitis.

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    Wu, Haichong; Zhao, Gan; Jiang, Kangfeng; Chen, Xiuying; Zhu, Zhe; Qiu, Changwei; Deng, Ganzhen

    2016-10-01

    Mastitis is defined as the inflammation of the mammary gland. There is generally no effective treatment for mastitis in animals. Puerarin, extracted from Radix puerariae, has been proven to possess many biological activities. The present study aims to reveal the potential mechanism that is responsible for the antiinflammatory action of puerarin in Staphylococcus aureus (S. aureus)-induced mastitis in mice. Histopathological changes showed that puerarin ameliorated the inflammatory injury induced by S. aureus. Quantitative real-time polymerase chain reaction and ELISA analysis indicated that puerarin not only suppressed the production of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 but also promoted the secretion of IL-10. Toll-like receptor 2 (TLR2) is important in the immune defense against S. aureus infection. Research in molecular biology has shown that the expression of TLR2 was inhibited with administration of puerarin. Further studies were performed on NF-kB and mitogen-activated protein kinase signaling pathways using western blot. The results demonstrated that puerarin suppressed phosphorylated IkBα, p65, p38, extracellular signal-regulated kinase 1and 2 (ERK), and c-Jun N-terminal kinase (JNK) in a dose-dependent manner. All of the results suggested that puerarin may be a potential therapy for treating mastitis. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Monoclonal antibodies protect from Staphylococcal Enterotoxin K (SEK) induced toxic shock and sepsis by USA300 Staphylococcus aureus.

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    Aguilar, Jorge L; Varshney, Avanish K; Pechuan, Ximo; Dutta, Kaushik; Nosanchuk, Joshua D; Fries, Bettina C

    2017-08-18

    Staphylococcus aureus is a leading infectious cause of life-threatening disease in humans, yet there is currently no vaccine to combat this bacterium. The pathogenesis of S. aureus is mediated by a diverse array of protein toxins including a large family of secreted pyrogenic superantigens. Neutralization of superantigens, including SEB and TSST-1, has proven to be protective in several animal models of toxic shock and sepsis. We demonstrate, for the first time, that a far more prevalent staphylococcal superantigen, SEK, can also induce lethal shock in mice. Additionally, we describe monoclonal antibodies (mAbs) that inhibit SEK-induced mitogenicity as well as protect against SEK-induced lethality, and enhance survival from S. aureus septicemia in murine models. MAb-4G3 (IgG2b), mAb-5G2 (IgG1), and mAb-9H2 (IgG1), all inhibit SEK-induced proliferation and cytokine production of human immune cells. We then demonstrate that passive immunization with a combination of mAb-4G3 and mAb-5G4, 2 mAbs that do not compete for epitope(s) on SEK, significantly enhance survival in a murine model of SEK-induced toxic shock (p = 0.006). In the setting of sepsis, passive immunization with this combination of mAbs also significantly enhances survival in mice after challenge with CA-MRSA strain USA300 (p = 0.03). Furthermore, septic mice that received mAb treatment in conjunction with vancomycin exhibit less morbidity than mice treated with vancomycin alone. Taken together, these findings suggest that the contribution of SEK to S. aureus pathogenesis may be greater than previously appreciated, and that adjunctive therapy with passive immunotherapy against SEs may be beneficial.

  15. Lipoteichoic acid and peptidoglycan from Staphylococcus aureus synergistically induce neutrophil influx into the lungs of mice

    NARCIS (Netherlands)

    Leemans, Jaklien C.; Heikens, Mirjam; van Kessel, Kok P. M.; Florquin, Sandrine; van der Poll, Tom

    2003-01-01

    Staphylococcus aureus is an important pathogen in nosocomial pneumonia. Lipoteichoic acid (LTA) and peptidoglycan (PepG) are part of the staphylococcal cell wall. Here we show that LTA and PepG act in synergy to cause polymorphonuclear cell recruitment in the pulmonary compartment during S. aureus

  16. Staphylococcus aureus Infection of Human Gestational Membranes Induces Bacterial Biofilm Formation and Host Production of Cytokines.

    Science.gov (United States)

    Doster, Ryan S; Kirk, Leslie A; Tetz, Lauren M; Rogers, Lisa M; Aronoff, David M; Gaddy, Jennifer A

    2017-02-15

    Staphylococcus aureus, a metabolically flexible gram-positive pathogen, causes infections in a variety of tissues. Recent evidence implicates S. aureus as an emerging cause of chorioamnionitis and premature rupture of membranes, which are associated with preterm birth and neonatal disease. We demonstrate here that S. aureus infects and forms biofilms on the choriodecidual surface of explanted human gestational membranes. Concomitantly, S. aureus elicits the production of proinflammatory cytokines, which could ultimately perturb maternal-fetal tolerance during pregnancy. Therefore, targeting the immunological response to S. aureus infection during pregnancy could attenuate disease among infected individuals, especially in the context of antibiotic resistance. Published by Oxford University Press for the Infectious Diseases Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  17. Heterologous protection against alpha toxins of Clostridium perfringens and Staphylococcus aureus induced by binding domain recombinant chimeric protein.

    Science.gov (United States)

    Uppalapati, Siva R; Kingston, Joseph J; Murali, Harishchandra S; Batra, Harsh V

    2014-05-23

    Clostridium perfringens and Staphylococcus aureus are the two important bacteria frequently associated with majority of the soft tissue infections. The severity and progression of the diseases caused by these pathogens are attributed primarily to the alpha toxins they produce. Previously, we synthesized a non-toxic chimeric molecule r-αCS encompassing the binding domains of C. perfringens and S. aureus alpha toxins and demonstrated that the r-αCS hyperimmune polysera reacts with both the native wild type toxins. In the present report, we evaluated efficacy of r-αCS in conferring protection against C. perfringens and S. aureus alpha toxin infections in murine model. Immunization of BALB/c with r-αCS was effective in inducing both high titers of serum anti-r-αCS antibodies after three administrations. Sub-typing the antibody pool revealed high proportions of IgG1 indicating a Th2-polarized immune response. The r-αCS stimulated the proliferation of splenocytes from the immunized mice upon re-induction by the antigen, in vitro. The levels of interleukin-10 increased while TNF-α was found to be downregulated in the r-αCS induced splenocytes. Mice immunized with r-αCS were protected against intramuscular challenge with 5×LD100 doses of C. perfringens and S. aureus alpha toxins with >80% survival, which killed control animals within 48-72h. Passive immunization of mice with anti-r-αCS serum resulted in 50-80% survival. Our results indicate that r-αCS is a remarkable antigen with protective efficacy against alpha toxin mediated C. perfringens and S. aureus soft tissue co-infections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Regulation of Expression of Oxacillin-Inducible Methionine Sulfoxide Reductases in Staphylococcus aureus

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    Kyle R. Baum

    2015-01-01

    Full Text Available Cell wall-active antibiotics cause induction of a locus that leads to elevated synthesis of two methionine sulfoxide reductases (MsrA1 and MsrB in Staphylococcus aureus. To understand the regulation of this locus, reporter strains were constructed by integrating a DNA fragment consisting of the msrA1/msrB promoter in front of a promoterless lacZ gene in the chromosome of wild-type and MsrA1-, MsrB-, MsrA1/MsrB-, and SigB-deficient methicillin-sensitive S. aureus strain SH1000 and methicillin-resistant S. aureus strain COL. These reporter strains were cultured in TSB and the cellular levels of β-galactosidase activity in these cultures were assayed during different growth phases. β-galactosidase activity assays demonstrated that the lack of MsrA1, MsrB, and SigB upregulated the msrA1/msrB promoter in S. aureus strain SH1000. In S. aureus strain COL, the highest level of β-galactosidase activity was observed under the conditions when both MsrA1 and MsrB proteins were absent. The data suggest that the msrA1/msrB locus, in part, is negatively regulated by MsrA1, MsrB, and SigB in S. aureus.

  19. Internalization of Staphylococcus aureus in Lymphocytes Induces Oxidative Stress and DNA Fragmentation: Possible Ameliorative Role of Nanoconjugated Vancomycin

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    Subhankari Prasad Chakraborty

    2011-01-01

    Full Text Available Staphylococcus aureus is the most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Lymphocyte is an important immune cell. The aim of the present paper was to test the ameliorative role of nanoconjugated vancomycin against Vancomycin-sensitive Staphylococcus aureus (VSSA and vancomycin-resistant Staphylococcus aureus (VRSA infection-induced oxidative stress in lymphocytes. VSSA and VRSA infections were developed in Swiss mice by intraperitoneal injection of 5×106 CFU/mL bacterial solutions. Nanoconjugated vancomycin was adminstrated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was adminstrated to VSSA- and VRSA-infected mice at a similar dose, respectively, for 10 days. Vancomycin and nanoconjugated vancomycin were adminstrated to normal mice at their effective doses for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, nitrite generation, nitrite release, and DNA damage and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group, which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VSSA and VRSA infection-induced oxidative stress in lymphocytes.

  20. Evaluation of constitutive and inducible resistance to clindamycin in clinical samples of Staphylococcus aureus from a tertiary hospital

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    Angelita Bottega

    2014-10-01

    Full Text Available Introduction Infections caused by methicillin-resistant Staphylococcus aureus (MRSA have become common in hospitals and the community environment, and this wide resistance has limited patient treatment. Clindamycin (CL represents an important alternative therapy for infections caused by S. aureus. Antimicrobial susceptibility testing using standard methods may not detect inducible CL resistance. This study was performed to detect the phenotypes of resistance to macrolides-lincosamides-streptogramin B (MLSB antibiotics, including CL, in clinical samples of S. aureus from patients at a tertiary hospital in Santa Maria, State of Rio Grande do Sul, Brazil. Methods One hundred and forty clinical isolates were submitted to the disk diffusion induction test (D-test with an erythromycin (ER disk positioned at a distance of 20mm from a CL disk. The results were interpreted according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI. Results In this study, 29 (20.7% of the 140 S. aureus samples were resistant to methicillin (MRSA, and 111 (79.3% were susceptible to methicillin (MSSA. The constitutive resistance phenotype (cMLSB was observed in 20 (14.3% MRSA samples and in 5 (3.6% MSSA samples, whereas the inducible resistance phenotype (iMLSB was observed in 3 (2.1% MRSA samples and in 8 (5.8% MSSA samples. Conclusions The D-test is essential for detecting the iMLSB phenotype because the early identification of this phenotype allows clinicians to choose an appropriate treatment for patients. Furthermore, this test is simple, easy to perform and inexpensive.

  1. NLRP3 Inflammasome Sequential Changes in Staphylococcus aureus-Induced Mouse Model of Acute Rhinosinusitis

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    Yan-Jun Wang

    2014-09-01

    Full Text Available The NLR pyrin domain containing 3 (NLRP3 inflammasome plays a crucial role in lung disease and may have a similar role in upper respiratory tract inflammation. We therefore constructed a C57BL/6 mouse model of acute rhinosinusitis induced by Staphylococcus aureus and investigated the role of the NLRP3 inflammasome in this model. Mice were classified as non-inoculated group (group A and inoculated groups (groups B, C, D and E, sacrificed 1, 3, 7 and 14 days after inoculation, respectively. Hematoxylin-eosin staining showed that each group had inflammatory cell infiltration, except group A. The damage of the nasal mucosa was aggravated gradually over time. Western blot and immunofluorescence showed that the structural proteins of the NLRP3 inflammasome (NLRP3, ASC (apoptosis-associated speck-like protein containing CARD, procaspase-1 in groups B, C, D and E were increased gradually. But they were reduced in group B compared with group A, except for NLRP3. Western blot showed that the cleavage fragment of procaspase-1, p20 in groups B, C, D and E was increased gradually. Real-time PCR showed that the corresponding mRNAs of the structural proteins were changed the same as their proteins. IL-1β mRNA and mature IL-1β protein were increased gradually in groups A, B, C, D and E. These results indicate that NLRP3 inflammasome activation was associated with the acute rhinosinusitis, and that there was a positive correlation between the expression level of the NLRP3 inflammasome and the severity of acute rhinosinusitis.

  2. NLRP3 inflammasome sequential changes in Staphylococcus aureus-induced mouse model of acute rhinosinusitis.

    Science.gov (United States)

    Wang, Yan-Jun; Gong, Guo-Qing; Chen, Shan; Xiong, Li-Yan; Zhou, Xing-Xing; Huang, Xiang; Kong, Wei-Jia

    2014-09-09

    The NLR pyrin domain containing 3 (NLRP3) inflammasome plays a crucial role in lung disease and may have a similar role in upper respiratory tract inflammation. We therefore constructed a C57BL/6 mouse model of acute rhinosinusitis induced by Staphylococcus aureus and investigated the role of the NLRP3 inflammasome in this model. Mice were classified as non-inoculated group (group A) and inoculated groups (groups B, C, D and E, sacrificed 1, 3, 7 and 14 days after inoculation, respectively). Hematoxylin-eosin staining showed that each group had inflammatory cell infiltration, except group A. The damage of the nasal mucosa was aggravated gradually over time. Western blot and immunofluorescence showed that the structural proteins of the NLRP3 inflammasome (NLRP3, ASC (apoptosis-associated speck-like protein containing CARD), procaspase-1) in groups B, C, D and E were increased gradually. But they were reduced in group B compared with group A, except for NLRP3. Western blot showed that the cleavage fragment of procaspase-1, p20 in groups B, C, D and E was increased gradually. Real-time PCR showed that the corresponding mRNAs of the structural proteins were changed the same as their proteins. IL-1β mRNA and mature IL-1β protein were increased gradually in groups A, B, C, D and E. These results indicate that NLRP3 inflammasome activation was associated with the acute rhinosinusitis, and that there was a positive correlation between the expression level of the NLRP3 inflammasome and the severity of acute rhinosinusitis.

  3. CHI3L1 regulation of inflammation and the effects on osteogenesis in a Staphylococcus aureus-induced murine model of osteomyelitis.

    Science.gov (United States)

    Chen, XueQiu; Jiao, Jian; He, XiaoQing; Zhang, JianPing; Wang, Hai; Xu, YongQing; Jin, Tao

    2017-06-01

    Osteomyelitis is an inflammation of the bone and bone marrow that occurs as a consequence of infections mainly attributed to Staphylococcus aureus. In a previous study, we found that expression of the chitinase 3-like 1 (CHI3L1) gene affected mineralization of MC3T3-E1 cells infected with S. aureus and there was increased expression of CHI3L1 in the blood of osteomyelitis patients. In the present study, to further investigate the role of CHI3L1 in osteomyelitis, we developed an S. aureus-induced murine model of the disease. We found that the expression of CHI3L1 was significantly up-regulated in femurs of mice infected with S. aureus compared with mice inoculated with a PBS control. To investigate these results further, we performed a CHI3L1 knock-down by lentivirus-mediated RNA interference in mice. Micro-computed tomography of infected femurs revealed that S. aureus triggers profound alterations in bone turnover, and femurs of CHI3L1 short hairpin RNA (shRNA-CHI3L1)-injected mice infected with S. aureus have significantly less cortical bone destruction when compared with control mice infected with S. aureus. Inhibition of CHI3L1 also decreased inflammation by reducing levels of proinflammatory cytokines and promoted the process of osteogenesis. The Notch signaling pathway has been shown to play an important role in modulating the differentiation of osteoblasts and osteoclasts. Our study showed that Notch1, Jagged1 and Hes1 expression significantly decreased in mice infected with S. aureus compared with the control, and shRNA-CHI3L1 could increase their level in S. aureus-infected mice. This research indicates that inhibition of CHI3L1 can reduce the debilitating effects of S. aureus in a murine model of osteomyelitis. © 2017 Federation of European Biochemical Societies.

  4. TNF-α increases Staphylococcus aureus-induced death of human alveolar epithelial cell line A549 associated with RIP3-mediated necroptosis.

    Science.gov (United States)

    Wen, Shun-Hang; Lin, Luo-Na; Wu, Hu-Jun; Yu, Lu; Lin, Li; Zhu, Li-Li; Li, Hai-Yan; Zhang, Hai-Lin; Li, Chang-Chong

    2018-02-15

    To explore the role of tumor necrosis factor-alpha (TNF-α) on Staphylococcus aureus-induced necroptosis in alveolar epithelial cells. The A549 alveolar epithelial cell line was pretreated with small interfering RNA (siRNA) against receptor interacting protein-3 (RIP3) and then stimulated by S. aureus, where some cells were pretreated with TNF-α or TNF-α with anti-TNF-α antibody simultaneously. A549 cell death was assessed using lactate dehydrogenase (LDH) leakage and flow cytometry analyses. The protein expressions of RIP1, RIP3, cleaved caspase-1, and cleaved caspase-8 were analyzed by western blot. S. aureus-induced LDH release was increased significantly by TNF-α. In addition, flow cytometry showed that TNF-α increased A549 cell apoptosis and necrosis in S. aureus-infected cell cultures. Levels of RIP3 and cleaved caspase-1 protein in A549 cells infected with S. aureus increased at 12 h post-infection, as shown by western blot. Significant additional increases in RIP3 expression were observed following the addition of TNF-α. Decreasing RIP3 levels by siRNA significantly suppressed the release of LDH induced by TNF-α and S. aureus. RIP3 siRNA also significantly suppressed A549 cell necrosis induced by S. aureus and TNF-α at 6 and 12 h post-infection as shown by flow cytometry analysis. TNF-α enhances the damage of S. aureus on lung epithelial cells, and its mechanism is associated with RIP3 mediated necroptosis. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Thioridazine induces major changes in global gene expression and cell wall composition in methicillin-resistant Staphylococcus aureus USA300.

    Directory of Open Access Journals (Sweden)

    Mette Thorsing

    Full Text Available Subinhibitory concentrations of the neuroleptic drug thioridazine (TDZ are well-known to enhance the killing of methicillin-resistant Staphylococcus aureus (MRSA by β-lactam antibiotics, however, the mechanism underlying the synergy between TDZ and β-lactams is not fully understood. In the present study, we have examined the effect of a subinhibitory concentration of TDZ on antimicrobial resistance, the global transcriptome, and the cell wall composition of MRSA USA300. We show that TDZ is able to sensitize the bacteria to several classes of antimicrobials targeting the late stages of peptidoglycan (PGN synthesis. Furthermore, our microarray analysis demonstrates that TDZ modulates the expression of genes encoding membrane and surface proteins, transporters, and enzymes involved in amino acid biosynthesis. Interestingly, resemblance between the transcriptional profile of TDZ treatment and the transcriptomic response of S. aureus to known inhibitors of cell wall synthesis suggests that TDZ disturbs PGN biosynthesis at a stage that precedes transpeptidation by penicillin-binding proteins (PBPs. In support of this notion, dramatic changes in the muropeptide profile of USA300 were observed following growth in the presence of TDZ, indicating that TDZ can interfere with the formation of the pentaglycine branches. Strikingly, the addition of glycine to the growth medium relieved the effect of TDZ on the muropeptide profile. Furthermore, exogenous glycine offered a modest protective effect against TDZ-induced β-lactam sensitivity. We propose that TDZ exposure leads to a shortage of intracellular amino acids, including glycine, which is required for the production of normal PGN precursors with pentaglycine branches, the correct substrate of S. aureus PBPs. Collectively, this work demonstrates that TDZ has a major impact on the cell wall biosynthesis pathway in S. aureus and provides new insights into how MRSA may be sensitized towards

  6. Delayed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibia after pin tract infection: two case reports.

    Science.gov (United States)

    Hamahashi, Kosuke; Uchiyama, Yoshiyasu; Kobayashi, Yuka; Watanabe, Masahiko

    2017-01-31

    Pin tract infection is a common complication of external fixation. It usually heals after treatment with debridement, antibiotics, and/or pin removal, only rarely developing into delayed osteomyelitis. We treated two patients with delayed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibia following pin tract infection. One patient, a diabetic 60-year-old Japanese man, underwent definitive external fixation using an Ilizarov fixator for postoperative osteomyelitis of an open fracture of his left ankle. One year after removing the external fixator, he developed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibial pin site. He underwent surgical debridement four times. No recurrence was seen 2 years 8 months after the last debridement. Another patient, a healthy 38-year-old Japanese man, underwent bilateral temporary external fixation for a right ankle open fracture and a comminuted fracture of the left tibial plateau. Three months after removal of the external fixator, he was diagnosed with methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the bilateral tibial pin sites. He underwent surgical debridement three times, but the infection of his right tibia persisted. Finally, a gastrocnemius muscle flap was placed. No recurrence was seen 2 years after this last surgery. Pin tract infection should not be considered a minor complication because osteomyelitis may develop, requiring treatment that is more aggressive than curettage of the pin tract. A gastrocnemius flap is a useful treatment option for refractory osteomyelitis because flap harvest causes less functional disturbance and is a relatively easy surgical technique.

  7. Staphylococcus aureus induces hypoxia and cellular damage in porcine dermal explants

    Science.gov (United States)

    Methicillin-resistant Staphylococcus aureus (MRSA) can infect wounds and produce difficult-to- treat biofilms. To determine the extent that MRSA biofilms can deplete oxygen, change pH and damage host tissue, we developed a porcine dermal explant model on which we cultured GFP-labeled MRSA biofilms. ...

  8. Puerarin protects against Staphylococcus aureus-induced injury of human alveolar epithelial A549 cells via downregulating alpha-hemolysin secretion.

    Science.gov (United States)

    Tang, Feng; Li, Wen-Hua; Zhou, Xuan; Liu, Yong-Hua; Li, Zhe; Tang, Yu-Shun; Kou, Xu; Wang, Shu-De; Bao, Min; Qu, Lian-Da; Li, Min; Li, Bing

    2014-08-01

    Alpha-hemolysin, a secreted pore-forming toxin, plays an indispensable role in the pathogenicity of Staphylococcus aureus. In this study, the antimicrobial activity of puerarin against S. aureus was investigated; as a result, puerarin showed no influence on the growth of this organism. However, hemolysis and western blotting assays showed that puerarin concentration dependently inhibited the secretion of alpha-hemolysin at low concentrations. Real-time RT-PCR assay was further employed to evaluate the transcriptional level of hla, the gene encoding alpha-hemolysin, and RNAIII, an effector molecule of the agr system. The results indicated that the RNAIII expression and subsequent hla transcription were also inhibited by puerarin in a dose-dependent manner. Furthermore, puerarin significantly prevented human alveolar epithelial A549 cells from S. aureus-induced injury. Thereby, puerarin may be considered as a potential candidate for the development of antivirulence drugs in the treatment of S. aureus-mediated infections.

  9. Commercial Biocides Induce Transfer of Prophage Φ13 from Human Strains of Staphylococcus aureus to Livestock CC398

    Directory of Open Access Journals (Sweden)

    Yuanyue Tang

    2017-12-01

    Full Text Available Human strains of Staphylococcus aureus commonly carry the bacteriophage ΦSa3 that encodes immune evasion factors. Recently, this prophage has been found in livestock-associated, methicillin resistant S. aureus (MRSA CC398 strains where it may promote human colonization. Here, we have addressed if exposure to biocidal products induces phage transfer, and find that during co-culture, Φ13 from strain 8325, belonging to ΦSa3 group, is induced and transferred from a human strain to LA-MRSA CC398 when exposed to sub-lethal concentrations of commercial biocides containing hydrogen peroxide. Integration of ΦSa3 in LA-MRSA CC398 occurs at multiple positions and the integration site influences the stability of the prophage. We did not observe integration in hlb encoding β-hemolysin that contains the preferred ΦSa3 attachment site in human strains, and we demonstrate that this is due to allelic variation in CC398 strains that disrupts the phage attachment site, but not the expression of β-hemolysin. Our results show that hydrogen peroxide present in biocidal products stimulate transfer of ΦSa3 from human to LA-MRSA CC398 strains and that in these strains prophage stability depends on the integration site. Knowledge of ΦSa3 transfer and stability between human and livestock strains may lead to new intervention measures directed at reducing human infection by LA-MRSA strains.

  10. ADAM10 mediates vascular injury induced by Staphylococcus aureus α-hemolysin.

    Science.gov (United States)

    Powers, Michael E; Kim, Hwan Keun; Wang, Yang; Bubeck Wardenburg, Juliane

    2012-08-01

    Staphylococcus aureus is a leading cause of bacteremia and sepsis. The interaction of S. aureus with the endothelium is central to bloodstream infection pathophysiology yet remains ill-understood. We show herein that staphylococcal α-hemolysin, a pore-forming cytotoxin, is required for full virulence in a murine sepsis model. The α-hemolysin binding to its receptor A-disintegrin and metalloprotease 10 (ADAM10) upregulates the receptor's metalloprotease activity on endothelial cells, causing vascular endothelial-cadherin cleavage and concomitant loss of endothelial barrier function. These cellular injuries and sepsis severity can be mitigated by ADAM10 inhibition. This study therefore provides mechanistic insight into toxin-mediated endothelial injury and suggests new therapeutic approaches for staphylococcal sepsis.

  11. Antimicrobial photodynamic therapy in chronic osteomyelitis induced by Staphylococcus aureus: An in vitro and in vivo study

    Science.gov (United States)

    dos Reis Júnior, João Alves; de Assis, Patrícia Nascimento; Paraguassú, Gardênia Matos; de Vieira de Castro, Isabele Cardoso; Trindade, Renan Ferreira; Marques, Aparecida Maria Cordeiro; Almeida, Paulo Fernando; Pinheiro, Antônio Luiz Barbosa

    2012-09-01

    Osteomyelitis it is an acute or chronic inflammation in the marrow spaces in the superficial or cortical bone, and associated to bacterial infection. Chronic osteomyelitis represents a major health problem due to its difficult treatment and increased morbidity. Antimicrobial photodynamic therapy (APT) by laser is a treatment based on a cytotoxic photochemical reaction in which, a bright light produced by a laser system and an active photosensitizer absorbed by cells leads an activation that induces a series of metabolic reactions that culminates a bacterial killing. The aim of this study was to assess, both in vitro and in vivo, the effect of lethal laser photosensitization on osteomyelitis. On the in vitro study a diode laser (λ660nm; 40mW; o/ = 0.4 cm2; 5 or 10 J/cm2) and 5, 10 and 15μg/mL toluidine blue (TB) were tested and the best parameter chosen for the in vivo study. The concentration of 5μg/mL was selected to perform the decontamination of infected by Staphylococcus aureus tibial bone defects in rats. The results were performed by ANOVA test. On the in vitro studies all PDTs groups in the different concentrations reduced significantly (pphotodynamic therapy using toluidine blue was effective in reducing the staphiloccocus aureus in both in vitro and in vivo studies.

  12. Lipoteichoic acid from Staphylococcus aureus induces lung endothelial cell barrier dysfunction: role of reactive oxygen and nitrogen species.

    Directory of Open Access Journals (Sweden)

    Amy Barton Pai

    Full Text Available Tunneled central venous catheters (TCVCs are used for dialysis access in 82% of new hemodialysis patients and are rapidly colonized with Gram-positive organism (e.g. Staphylococcus aureus biofilm, a source of recurrent infections and chronic inflammation. Lipoteichoic acid (LTA, a cell wall ribitol polymer from Gram-positive organisms, mediates inflammation through the Toll-like receptor 2 (TLR2. The effect of LTA on lung endothelial permeability is not known. We tested the hypothesis that LTA from Staphylococcus aureus induces alterations in the permeability of pulmonary microvessel endothelial monolayers (PMEM that result from activation of TLR2 and are mediated by reactive oxygen/nitrogen species (RONS. The permeability of PMEM was assessed by the clearance rate of Evans blue-labeled albumin, the activation of the TLR2 pathway was assessed by Western blot, and the generation of RONS was measured by the fluorescence of oxidized dihydroethidium and a dichlorofluorescein derivative. Treatment with LTA or the TLR2 agonist Pam((3CSK((4 induced significant increases in albumin permeability, IκBα phosphorylation, IRAK1 degradation, RONS generation, and endothelial nitric oxide synthase (eNOS activation (as measured by the p-eNOS(ser1177:p-eNOS(thr495 ratio. The effects on permeability and RONS were effectively prevented by co-administration of the superoxide scavenger Tiron, the peroxynitrite scavenger Urate, or the eNOS inhibitor L-NAME and these effects as well as eNOS activation were reduced or prevented by pretreatment with an IRAK1/4 inhibitor. The results indicate that the activation of TLR2 and the generation of ROS/RNS mediates LTA-induced barrier dysfunction in PMEM.

  13. Brazilin plays an anti-inflammatory role with regulating Toll-like receptor 2 and TLR 2 downstream pathways in Staphylococcus aureus-induced mastitis in mice.

    Science.gov (United States)

    Gao, Xue-jiao; Wang, Tian-cheng; Zhang, Ze-cai; Cao, Yong-guo; Zhang, Nai-sheng; Guo, Meng-yao

    2015-07-01

    Mastitis, which commonly occurs during the postpartum period, is caused by the infection of the mammary glands. The most common infectious bacterial pathogen of mastitis is Staphylococcus aureus (S. aureus) in both human and animals. Brazilin, a compound isolated from the traditional herbal medicine Caesalpinia sappan L., has been shown to exhibit multiple biological properties. The present study was performed to determine the effect of brazilin on the inflammatory response in the mouse model of S. aureus mastitis and to confirm the mechanism of action involved. Brazilin treatment was applied in both a mouse model and cells. After brazilin treatment of cells, Western blotting and qPCR were performed to detect the protein levels and mRNA levels, respectively. Brazilin treatment significantly attenuated inflammatory cell infiltration and inhibited the expressions of TNF-α, IL-1β and IL-6 in a dose-dependent manner. Administration of brazilin in mice suppressed S. aureus-induced inflammatory injury and the production of proinflammatory mediators. This suppression was achieved by reducing the increased expression of TLR2 and regulating the NF-κB and MAPK signaling pathways in the mammary gland tissues and cells with S. aureus-induced mastitis. These results suggest that brazilin appears to be an effective drug for the treatment of mastitis and may be applied as a clinical therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. A microfluidic platform for rapid, stress-induced antibiotic susceptibility testing of Staphylococcus aureus.

    Science.gov (United States)

    Kalashnikov, Maxim; Lee, Jean C; Campbell, Jennifer; Sharon, Andre; Sauer-Budge, Alexis F

    2012-11-07

    The emergence and spread of bacterial resistance to ever increasing classes of antibiotics intensifies the need for fast phenotype-based clinical tests for determining antibiotic susceptibility. Standard susceptibility testing relies on the passive observation of bacterial growth inhibition in the presence of antibiotics. In this paper, we present a novel microfluidic platform for antibiotic susceptibility testing based on stress-activation of biosynthetic pathways that are the primary targets of antibiotics. We chose Staphylococcus aureus (S. aureus) as a model system due to its clinical importance, and we selected bacterial cell wall biosynthesis as the primary target of both stress and antibiotic. Enzymatic and mechanical stresses were used to damage the bacterial cell wall, and a β-lactam antibiotic interfered with the repair process, resulting in rapid cell death of strains that harbor no resistance mechanism. In contrast, resistant bacteria remained viable under the assay conditions. Bacteria, covalently-bound to the bottom of the microfluidic channel, were subjected to mechanical shear stress created by flowing culture media through the microfluidic channel and to enzymatic stress with sub-inhibitory concentrations of the bactericidal agent lysostaphin. Bacterial cell death was monitored via fluorescence using the Sytox Green dead cell stain, and rates of killing were measured for the bacterial samples in the presence and absence of oxacillin. Using model susceptible (Sanger 476) and resistant (MW2) S. aureus strains, a metric was established to separate susceptible and resistant staphylococci based on normalized fluorescence values after 60 min of exposure to stress and antibiotic. Because this ground-breaking approach is not based on standard methodology, it circumvents the need for minimum inhibitory concentration (MIC) measurements and long wait times. We demonstrate the successful development of a rapid microfluidic-based and stress

  15. Evaluation of a Novel Chimeric B Cell Epitope-Based Vaccine against Mastitis Induced by Either Streptococcus agalactiae or Staphylococcus aureus in Mice▿

    Science.gov (United States)

    Xu, Haiyang; Hu, Changmin; Gong, Rui; Chen, Yingyu; Ren, Ningning; Xiao, Ganwen; Xie, Qian; Zhang, Minmin; Liu, Qin; Guo, Aizhen; Chen, Huanchun

    2011-01-01

    To construct a universal vaccine against mastitis induced by either Streptococcus agalactiae or Staphylococcus aureus, the B cell epitopes of the surface immunogenic protein (Sip) from S. agalactiae and clumping factor A (ClfA) from S. aureus were analyzed and predicted. sip-clfA, a novel chimeric B cell epitope-based gene, was obtained by overlap PCR, and then the recombinant Sip-ClfA (rSip-ClfA) was expressed and purified. rSip-ClfA and inactivated S. agalactiae and S. aureus were formulated into different vaccines with mineral oil as the adjuvant and evaluated in mouse models. The rSip-ClfA vaccination induced immunoglobulin G (IgG) titers higher than those seen in groups immunized with inactivated bacteria. Furthermore, the response to rSip-ClfA immunization was characterized as having a dominant IgG1 subtype, whereas both bacterial immunizations produced similar levels of IgG1 and IgG2a. The antiserum capacities for opsonizing adhesion and phagocytosis were significantly greater in the rSip-ClfA immunization group than in the killed-bacterium immunization groups (P aureus via the intramammary route. At 24 h postinfection, the numbers of bacteria recovered from the mammary glands in the rSip-ClfA group were >5-fold lower than those in both inactivated-bacterium groups (P aureus challenges. Thus, the recombinant protein rSip-ClfA would be a promising vaccine candidate against mastitis induced by either S. agalactiae or S. aureus. PMID:21508165

  16. Short communication: Antimicrobial efficacy of intramammary treatment with a novel biphenomycin compound against Staphylococcus aureus, Streptococcus uberis, and Escherichia coli-induced mouse mastitis.

    Science.gov (United States)

    Demon, Dieter; Breyne, Koen; Schiffer, Guido; Meyer, Evelyne

    2013-01-01

    Bovine mastitis undermines udder health, jeopardizes milk production, and entails prohibitive costs, estimated at $2 billion per year in the dairy industry of the United States. Despite intensive research, the dairy industry has not managed to eradicate the 3 major bovine mastitis-inducing pathogens: Staphylococcus aureus, Streptococcus uberis, and Escherichia coli. In this study, the antimicrobial efficacy of a newly formulated biphenomycin compound (AIC102827) was assessed against intramammary Staph. aureus, Strep. uberis, and E. coli infections, using an experimental mouse mastitis model. Based on its effective and protective doses, AIC102827 applied into the mammary gland was most efficient to treat Staph. aureus, but also adequately reduced growth of Strep. uberis or E. coli, indicating its potential as a broad-spectrum candidate to treat staphylococcal, streptococcal, and coliform mastitis in dairy cattle. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  17. Staphylococcus aureus Alpha-Toxin Induces the Formation of Dynamic Tubules Labeled with LC3 within Host Cells in a Rab7 and Rab1b-Dependent Manner

    Directory of Open Access Journals (Sweden)

    María M. López de Armentia

    2017-10-01

    Full Text Available Staphylococcus aureus is a pathogen that causes severe infectious diseases that eventually lead to septic and toxic shock. S. aureus infection is characterized by the production of virulence factors, including enzymes and toxins. After internalization S. aureus resides in a phagosome labeled with Rab7 protein. Here, we show that S. aureus generates tubular structures marked with the small GTPases Rab1b and Rab7 and by the autophagic protein LC3 at early times post-infection. As shown by live cell imaging these tubular structures are highly dynamic, extend, branch and grow in length. We have named them S. aureus induced filaments (Saf. Furthermore, we demonstrate that the formation of these filaments depends on the integrity of microtubules and the activity of the motor protein Kinesin-1 (Kif5B and the Rab-interacting lysosomal protein (RILP. Our group has previously reported that α-hemolysin, a secreted toxin of S. aureus, is responsible of the activation of the autophagic pathway induced by the bacteria. In the present report, we demonstrate that the autophagic protein LC3 is recruited to the membrane of S. aureus induced filaments and that α-hemolysin is the toxin that induces Saf formation. Interestingly, increasing the levels of intracellular cAMP significantly inhibited Saf biogenesis. Remarkably in this report we show the formation of tubular structures that emerge from the S. aureus-containing phagosome and that these tubules generation seems to be required for efficient bacteria replication.

  18. An Important Role of α-Hemolysin in Extracellular Vesicles on the Development of Atopic Dermatitis Induced by Staphylococcus aureus

    OpenAIRE

    Hong, Sung-Wook; Choi, Eun-Byul; Min, Taek-Ki; Kim, Ji-Hyun; Kim, Min-Hye; Jeon, Seong Gyu; Lee, Byung-Jae; Gho, Yong Song; Jee, Young-Koo; Pyun, Bok-Yang; Kim, Yoon-Keun

    2014-01-01

    Skin barrier disruption and dermal inflammation are key phenotypes of atopic dermatitis (AD). Staphylococcus aureus secretes extracellular vesicles (EVs), which are involved in AD pathogenesis. Here, we evaluated the role of EVs-associated α-hemolysin derived from S. aureus in AD pathogenesis. α-hemolysin production from S. aureus was detected using western blot analyses. The cytotoxic activity of α-hemolysin on HaCaT keratinocytes was evaluated by measuring cell viability after treating cell...

  19. Polydatin ameliorates Staphylococcus aureus-induced mastitis in mice via inhibiting TLR2-mediated activation of the p38 MAPK/NF-κB pathway.

    Science.gov (United States)

    Jiang, Kang-Feng; Zhao, Gan; Deng, Gan-Zhen; Wu, Hai-Chong; Yin, Nan-Nan; Chen, Xiu-Ying; Qiu, Chang-Wei; Peng, Xiu-Li

    2017-02-01

    Recent studies show that Polydatin (PD) extracted from the roots of Polygonum cuspidatum Sieb, a widely used traditional Chinese remedies, possesses anti-inflammatory activity in several experimental models. In this study, we investigated the anti-inflammatory effects of PD on Staphylococcus aureus-induced mastitis in mice and elucidated the potential mechanisms. In mice with S aureus-induced mastitis, administration of PD (15, 30, 45 mg/kg, ip) or dexamethasone (Dex, 5 mg/kg, ip) significantly suppressed the infiltration of inflammatory cells, ameliorated the mammary structural damage, and inhibited the activity of myeloperoxidase, a biomarker of neutrophils accumulation. Furthermore, PD treatment dose-dependently decreased the levels of TNF-α, IL-1β, IL-6 and IL-8 in the mammary gland tissues. PD treatment also dose-dependently decreased the expression of TLR2, MyD88, IRAK1, IRAK4 and TRAF6 as well as the phosphorylation of TAK1, MKK3/6, p38 MAPK, IκB-α and NF-κB in the mammary gland tissues. In mouse mammary epithelial cells (mMECs) infected by S aureus in vitro, pretreatment with PD dose-dependently suppressed the upregulated pro-inflammatory cytokines and signaling proteins, and the nuclear translocation of NF-κB p65 and AP-1. A TLR2-neutralizing antibody mimicked PD in its suppression on S aureus-induced upregulation of MyD88, p-p38 and p-p65 levels in mMECs. PD (50, 100 μg/mL) affected neither the growth of S aureus in vitro, nor the viability of mMECs. In conclusion, PD does not exhibit antibacterial activity against S aureus, its therapeutic effects in mouse S aureus-induced mastitis depend on its ability to down-regulate pro-inflammatory cytokine levels via inhibiting TLR2-mediated activation of the p38 MAPK/NF-κB signaling pathway.

  20. Evaluation of a novel chimeric B cell epitope-based vaccine against mastitis induced by either Streptococcus agalactiae or Staphylococcus aureus in mice.

    Science.gov (United States)

    Xu, Haiyang; Hu, Changmin; Gong, Rui; Chen, Yingyu; Ren, Ningning; Xiao, Ganwen; Xie, Qian; Zhang, Minmin; Liu, Qin; Guo, Aizhen; Chen, Huanchun

    2011-06-01

    To construct a universal vaccine against mastitis induced by either Streptococcus agalactiae or Staphylococcus aureus, the B cell epitopes of the surface immunogenic protein (Sip) from S. agalactiae and clumping factor A (ClfA) from S. aureus were analyzed and predicted. sip-clfA, a novel chimeric B cell epitope-based gene, was obtained by overlap PCR, and then the recombinant Sip-ClfA (rSip-ClfA) was expressed and purified. rSip-ClfA and inactivated S. agalactiae and S. aureus were formulated into different vaccines with mineral oil as the adjuvant and evaluated in mouse models. The rSip-ClfA vaccination induced immunoglobulin G (IgG) titers higher than those seen in groups immunized with inactivated bacteria. Furthermore, the response to rSip-ClfA immunization was characterized as having a dominant IgG1 subtype, whereas both bacterial immunizations produced similar levels of IgG1 and IgG2a. The antiserum capacities for opsonizing adhesion and phagocytosis were significantly greater in the rSip-ClfA immunization group than in the killed-bacterium immunization groups (P 5-fold lower than those in both inactivated-bacterium groups (P < 0.01). Histopathological examination of the mammary glands showed that rSip-ClfA immunization provided better protection of mammary gland tissue integrity against both S. agalactiae and S. aureus challenges. Thus, the recombinant protein rSip-ClfA would be a promising vaccine candidate against mastitis induced by either S. agalactiae or S. aureus.

  1. Ex vivo efficacy of gemifloxacin in experimental keratitis induced by methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Marino, Andreana; Blanco, Anna Rita; Ginestra, Giovanna; Nostro, Antonia; Bisignano, Giuseppe

    2016-10-01

    In recent years, the emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains has been observed in ocular infections. Resistance of MRSA to second- and third-generation fluoroquinolones has increased interest in the fourth-generation fluoroquinolones. In this study, the antibacterial activity of gemifloxacin against MRSA ocular isolates in vitro and in a modified ex vivo rabbit keratitis model was investigated. In vitro susceptibility test results indicated that the minimum inhibitory concentrations (MICs) of gemifloxacin were lower than the MICs of other fluoroquinolones, including moxifloxacin (MIC50 range, 0.016-0.032 µg/mL; MIC90 range, 0.047-0.094 µg/mL). Results from the ex vivo keratitis model showed a statistically significant decrease in MRSA counts (0.5-2 log10 CFU/g; P keratitis. In addition, this reproducible, ethical and economic ex vivo infection model can be used as a mechanistically-based alternative to in vivo animal testing, bridging the gap between in vitro and in vivo results. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  2. Mesenchymal stromal cell implantation for stimulation of long bone healing aggravates Staphylococcus aureus induced osteomyelitis.

    Science.gov (United States)

    Seebach, Elisabeth; Holschbach, Jeannine; Buchta, Nicole; Bitsch, Rudi Georg; Kleinschmidt, Kerstin; Richter, Wiltrud

    2015-07-01

    Large bone defects requiring long-term osteosynthetic stabilization or repeated surgeries show a considerable rate of infection. Mesenchymal stromal cells (MSCs) have been successfully used to enhance bone regeneration, but their powerful immunomodulatory effects may impose an enhanced risk for osteomyelitis development. In order to unravel whether implantation of MSCs aggravates a simultaneous bone infection, a hydrogel-supported osteomyelitis ostectomy model was developed in which rats received a femoral bone defect with rigid plate-fixation. After fibrin-assisted transfer of Staphylococcus aureus (SA), effects of MSC implantation on osteomyelitis development were quantified over 3-4 weeks. All SA-infected animals developed an acute local osteomyelitis with significantly increased blood neutrophil count, abscess formation and bone destruction. MSC-treatment of infected defects aggravated osteomyelitis according to a significantly elevated osteomyelitis score and enhanced distal bone loss with spongy alteration of cortical bone architecture. Increased attraction of macrophages, osteoclasts and regulation of pro- and anti-inflammatory mediators were potential MSC actions. Overall trophic actions of MSCs implanted into non-sterile bone defects may enhance an infection and/or exacerbate osteomyelitis. Studies on antibiotic carrier augmentation or antibiotic treatment are warranted to decide whether MSC implantation is a safe and promising therapy for orthopedic implant-stabilized bone defects at high risk for development of infection. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Naja naja atra and Naja nigricollis cardiotoxins induce fusion of Escherichia coli and Staphylococcus aureus membrane-mimicking liposomes.

    Science.gov (United States)

    Kao, Pei-Hsiu; Lin, Shinne-Ren; Hu, Wan-Ping; Chang, Long-Sen

    2012-09-01

    Our previous studies showed that the bactericidal effect of Naja naja atra cardiotoxin 3 (CTX3) and Naja nigricollis toxin γ was associated with their membrane-damaging activity. To elucidate the mechanism responsible for CTX3- and toxin γ-induced membrane permeability, we investigated the interacted mode of CTX3 and toxin γ with model membrane of Escherichia coli (phosphatidylethanolamine (PE)/phosphatidylglycerol (PG), mol/mol, 75/25) and Staphylococcus aureus (PG/cardiolipin, mol/mol, 60/40) in this study. Membrane-damaging activity of toxin γ on PE/PG and PG/cardiolipin vesicles were similar, while CTX3-induced leakage of PG/cardiolipin vesicles was notably higher than that of PE/PG vesicles. Noticeably, fusogenic activity of CTX3 and toxin γ on the phospholipid vesicles correlated positively with their membrane-damaging activity. Unlike toxin γ, CTX3 induced increasingly leakage and fusion of phospholipid vesicles with increased cardiolipin content. Changes in membrane fluidity and lipid packing occurred with the binding of CTX3 and toxin γ with vesicles, reflecting the penetration of toxin molecules into membrane bilayers. Consistent with the finding that PE/PG and PG/cardiolipin vesicles induced differently conformational changes of CTX3 and toxin γ, CTX3 and toxin γ adopted different membrane bound-mode upon absorption onto either PE/PG or PG/cardiolipin vesicles. Taken together, our data indicate that membrane-bound mode and membrane-perturbing effect of CTX3 and toxin γ in concert with targeted membrane compositions determine their fusogenicity and membrane-damaging activity, and suggest a causal relationship between bactericidal activity and fusogenicity of CTX3 and toxin γ. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Commercial biocides induce transfer of prophage Φ13 from human strains of Staphylococcus aureus to livestock CC398

    DEFF Research Database (Denmark)

    Tang, Yuanyue; Nielsen, Lene Nørby; Hvitved, Annemette

    2017-01-01

    Human strains of Staphylococcus aureus commonly carry the bacteriophage ΦSa3 that encodes immune evasion factors. Recently, this prophage has been found in livestock-associated, methicillin resistant S. aureus (MRSA) CC398 strains where it may promote human colonization. Here, we have addressed ...

  5. Abscess formation and alpha-hemolysin induced toxicity in a mouse model of Staphylococcus aureus peritoneal infection.

    Science.gov (United States)

    Rauch, Sabine; DeDent, Andrea C; Kim, Hwan Keun; Bubeck Wardenburg, Juliane; Missiakas, Dominique M; Schneewind, Olaf

    2012-10-01

    Staphylococcus aureus is a frequent cause of skin infection and sepsis in humans. Preclinical vaccine studies with S. aureus have used a mouse model with intraperitoneal challenge and survival determination as a measure for efficacy. To appreciate the selection of protective antigens in this model, we sought to characterize the pathological attributes of S. aureus infection in the peritoneal cavity. Testing C57BL/6J and BALB/c mice, >10(9) CFU of S. aureus Newman were needed to produce a lethal outcome in 90% of animals infected via intraperitoneal injection. Both necropsy and histopathology revealed the presence of intraperitoneal abscesses in the vicinity of inoculation sites. Abscesses were comprised of fibrin as well as collagen deposits and immune cells with staphylococci replicating at the center of these lesions. Animals that succumbed to challenge harbored staphylococci in abscess lesions and in blood. The establishment of lethal infections, but not the development of intraperitoneal abscesses, was dependent on S. aureus expression of alpha-hemolysin (Hla). Active immunization with nontoxigenic Hla(H35L) or passive immunization with neutralizing monoclonal antibodies protected mice against early lethal events associated with intraperitoneal S. aureus infection but did not affect the establishment of abscess lesions. These results characterize a mouse model for the study of intraperitoneal abscess formation by S. aureus, a disease that occurs frequently in humans undergoing continuous ambulatory peritoneal dialysis for end-stage renal disease.

  6. Low Fluid Shear Culture of Staphylococcus Aureus Represses hfq Expression and Induces an Attachment-Independent Biofilm Phenotype

    Science.gov (United States)

    Ott, C. Mark; Castro, S. L.; Nickerson, C. A.; Nelman-Gonzalez, M.

    2011-01-01

    Background: The opportunistic pathogen, Staphylococcus aureus, experiences fluctuations in fluid shear during infection and colonization of a human host. Colonization frequently occurs at mucus membrane sites such as in the gastrointestinal tract where the bacterium may experience low levels of fluid shear. The response of S. aureus to low fluid shear remains unclear. Methods: S. aureus was cultured to stationary phase using Rotating-Wall Vessel (RWV) bioreactors which produce a physiologically relevant low fluid shear environment. The bacterial aggregates that developed in the RWV were evaluated by electron microscopy as well as for antibiotic resistance and other virulence-associated stressors. Genetic expression profiles for the low-shear cultured S. aureus were determined by microarray analysis and quantitative real-time PCR. Results: Planktonic S. aureus cultures in the low-shear environment formed aggregates completely encased in high amounts of extracellular polymeric substances. In addition, these aggregates demonstrated increased antibiotic resistance indicating attachment-independent biofilm formation. Carotenoid production in the low-shear cultured S. aureus was significantly decreased, and these cultures displayed an increased susceptibility to oxidative stress and killing by whole blood. The hfq gene, associated with low-shear growth in Gram negative organisms, was also found to be down-regulated in S. aureus. Conclusions: Collectively, this data suggests that S. aureus decreases virulence characteristics in favor of a biofilm-dwelling colonization phenotype in response to a low fluid shear environment. Furthermore, the identification of an Hfq response to low-shear culture in S. aureus, in addition to the previously reported responses in Gram negative organisms, strongly suggests an evolutionarily conserved response to mechanical stimuli among structurally diverse prokaryotes.

  7. Membrane Destruction and DNA Binding of Staphylococcus aureus Cells Induced by Carvacrol and Its Combined Effect with a Pulsed Electric Field.

    Science.gov (United States)

    Wang, Lang-Hong; Wang, Man-Sheng; Zeng, Xin-An; Zhang, Zhi-Hong; Gong, De-Ming; Huang, Yan-Bo

    2016-08-17

    Carvacrol (5-isopropyl-2-methylphenol, CAR) is an antibacterial ingredient that occurs naturally in the leaves of the plant Origanum vulgare. The antimicrobial mechanism of CAR against Staphylococcus aureus ATCC 43300 was investigated in the study. Analysis of the membrane fatty acids by gas chromatography-mass spectrometry (GC-MS) showed that exposure to CAR at low concentrations induced a marked increase in the level of unbranched fatty acids (from 34.90 ± 1.77% to 62.37 ± 4.26%). Moreover, CAR at higher levels severely damaged the integrity and morphologies of the S. aureus cell membrane. The DNA-binding properties of CAR were also investigated using fluorescence, circular dichroism, molecular modeling, and atomic-force microscopy. The results showed that CAR bound to DNA via the minor-groove mode, mildly perturbed the DNA secondary structure, and induced DNA molecules to be aggregated. Furthermore, a combination of CAR with a pulsed-electric field was found to exhibit strong synergistic effects on S. aureus.

  8. Escherichia coli-derived and Staphylococcus aureus-derived extracellular vesicles induce MUC5AC expression via extracellular signal related kinase 1/2 and p38 mitogen-activated protein kinase in human airway epithelial cells.

    Science.gov (United States)

    Bae, Chang Hoon; Choi, Yoon Seok; Song, Si-Youn; Kim, Yoon-Keun; Kim, Yong-Dae

    2017-01-01

    Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) release extracellular vesicles (EVs). E. coli-derived and S. aureus-derived EVs are associated with neutrophilic respiratory inflammation. In neutrophilic respiratory inflammation of human, expression of mucin is increased in airway epithelial cells and is associated with increased morbidity and mortality of the affected patients. However, no study on the effects of EVs on expression of mucin genes has been reported in airway epithelial cells. Therefore, this study was conducted in order to examine the effects and the brief signaling pathways of E. coli-derived and S. aureus-derived EVs on MUC5AC expression in human airway epithelial cells. In mucin-producing human NCI-H292 airway epithelial cells and primary cultures of normal nasal epithelial cells, the effects and signaling pathways of E. coli-derived and S. aureus-derived EVs on MUC5AC expression were examined using reverse transcription-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with several specific inhibitors and small interfering RNA (siRNA). E. coli-derived and S. aureus-derived EVs induced MUC5AC expression. E. coli-derived and S. aureus-derived EVs significantly activated phosphorylation of extracellular signal related kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) and p38 MAPK. ERK1/2 MAPK inhibitor, p38 MAPK inhibitor, ERK1/2 MAPK siRNA, and p38 MAPK siRNA significantly blocked E. coli-derived and S. aureus-derived EVs induced MUC5AC messenger RNA (mRNA) expression. The results of this study suggest that E. coli-derived and S. aureus-derived EVs induced MUC5AC expression via ERK1/2 and p38 MAPK signaling pathways in human airway epithelial cells. © 2016 ARS-AAOA, LLC.

  9. Evaluation of a Nisin-Eluting Nanofiber Scaffold To Treat Staphylococcus aureus-Induced Skin Infections in Mice

    Science.gov (United States)

    Heunis, Tiaan D. J.; Smith, Carine

    2013-01-01

    Staphylococcus aureus is a virulent pathogen and a major causative agent of superficial and invasive skin and soft tissue infections (SSSTIs). Antibiotic resistance in S. aureus, among other bacterial pathogens, has rapidly increased, and this is placing an enormous burden on the health care sector and has serious implications for infected individuals, especially immunocompromised patients. Alternative treatments thus need to be explored to continue to successfully treat infections caused by S. aureus, including antibiotic-resistant strains of S. aureus. In this study, an antimicrobial nanofiber wound dressing was generated by electrospinning nisin (Nisaplin) into poly(ethylene oxide) and poly(d,l-lactide) (50:50) blend nanofibers. Active nisin diffused from the nanofiber wound dressings for at least 4 days in vitro, as shown by consecutive transfers onto plates seeded with strains of methicillin-resistant S. aureus (MRSA). The nisin-containing nanofiber wound dressings significantly reduced S. aureus Xen 36 bioluminescence in vivo and viable cell numbers in a murine excisional skin infection model. The bacterial burden of wounds treated with nisin-containing nanofiber wound dressings was 4.3 × 102 CFU/wound, whereas wounds treated with control nanofiber wound dressings had 2.2 × 107 CFU/wound on the last day of the trial (day 7). Furthermore, the wound dressings stimulated wound closure of excisional wounds, and no adverse effects were observed by histological analysis. Nisin-containing nanofiber wound dressings have the potential to treat S. aureus skin infections and to potentially accelerate wound healing of excisional wounds. PMID:23733456

  10. Habituation of enterotoxigenic Staphylococcus aureus to Origanum vulgare L. essential oil does not induce direct-tolerance and cross-tolerance to salts and organic acids

    Directory of Open Access Journals (Sweden)

    Adassa Gama Tavares

    2015-09-01

    Full Text Available Enterotoxigenic Staphylococcus aureus strains that were isolated from foods were investigated for their ability to develop direct-tolerance and cross-tolerance to sodium chloride (NaCl, potassium chloride (KCl, lactic acid (LA and acetic acid (AA after habituation in sublethal amounts (1/2 of the minimum inhibitory concentration - 1/2 MIC and 1/4 of the minimum inhibitory concentration - 1/4 MIC of Origanum vulgare L. essential oil (OVEO. The habituation of S. aureus to 1/2 MIC and 1/4 MIC of OVEO did not induce direct-tolerance or cross-tolerance in the tested strains, as assessed by modulation of MIC values. Otherwise, exposing the strains to OVEO at sublethal concentrations maintained or increased the sensitivity of the cells to the tested stressing agents because the MIC values of OVEO, NaCl, KCl, LA and AA against the cells that were previously habituated to OVEO remained the same or decreased when compared with non-habituated cells. These data indicate that OVEO does not have an inductive effect on the acquisition of direct-tolerance or cross-tolerance in the tested enterotoxigenic strains of S. aureus to antimicrobial agents that are typically used in food preservation.

  11. Habituation of enterotoxigenic Staphylococcus aureus to Origanum vulgare L. essential oil does not induce direct-tolerance and cross-tolerance to salts and organic acids.

    Science.gov (United States)

    Tavares, Adassa Gama; Monte, Daniel Farias Marinho do; Albuquerque, Allan Dos Reis; Sampaio, Fábio Correia; Magnani, Marciane; Siqueira Júnior, José Pinto de; Souza, Evandro Leite de

    2015-01-01

    Enterotoxigenic Staphylococcus aureus strains that were isolated from foods were investigated for their ability to develop direct-tolerance and cross-tolerance to sodium chloride (NaCl), potassium chloride (KCl), lactic acid (LA) and acetic acid (AA) after habituation in sublethal amounts (1/2 of the minimum inhibitory concentration - 1/2 MIC and 1/4 of the minimum inhibitory concentration - 1/4 MIC) of Origanum vulgare L. essential oil (OVEO). The habituation of S. aureus to 1/2 MIC and 1/4 MIC of OVEO did not induce direct-tolerance or cross-tolerance in the tested strains, as assessed by modulation of MIC values. Otherwise, exposing the strains to OVEO at sublethal concentrations maintained or increased the sensitivity of the cells to the tested stressing agents because the MIC values of OVEO, NaCl, KCl, LA and AA against the cells that were previously habituated to OVEO remained the same or decreased when compared with non-habituated cells. These data indicate that OVEO does not have an inductive effect on the acquisition of direct-tolerance or cross-tolerance in the tested enterotoxigenic strains of S. aureus to antimicrobial agents that are typically used in food preservation.

  12. Combined antibiotic and free radical trap treatment is effective at combating Staphylococcus-aureus-induced septic arthritis

    Science.gov (United States)

    Sakiniene, Egidija; Collins, L Vincent

    2002-01-01

    Although early antibiotic treatment of patients with septic arthritis eradicates bacteria, joint destruction commonly results from the unregulated host inflammatory responses to infection. The spin trap compound phenyl-N-tert-butyl nitrone (PBN) has been shown to have both anti-inflammatory and antioxidant effects. The aim of this study was to assess the effect of combined systemic administration of PBN and cloxacillin on the development of Staphylococcus aureus arthritis. Three days after Naval Medical Research Institute (NMRI) mice were infected intravenously with S. aureus LS-1, daily treatment was started with cloxacillin alone, PBN alone, or cloxacillin and PBN. Arthritis, weight loss and general condition were evaluated for each mouse, and joints were analyzed histopathologically. Systemic administration of PBN in conjunction with cloxacillin ameliorated the course of experimental S. aureus arthritis, as evidenced by an increased cure rate. Thus, combinatorial antioxidant plus antibiotic anti-inflammatory therapies represent a potentially efficacious approach to the management of septic arthritis. PMID:12010570

  13. The Experimental Study on Anti-bacterial Potency of Various Herbal Eye drops on Staphylococcus aureus induced keratitis

    Directory of Open Access Journals (Sweden)

    Hyeong-sik Seo

    2008-03-01

    Full Text Available Objectives : This experimental study was performed to investigate the effect of herbal eye drops(Sean-tang, Jinpi-san, Tangpo-san, Copitdis Rhizoma on Staphylococcus aureus keratitis. Methods : After administering various herbal eye drops on Staphylococcus aureus, I measured MIC and the size of inhibition zone. MIC was measured by dropping from 20 to 50㎕ according to density. Anti-bacterial potency was measured by the size of inhibition zone with change of volume under2days culture condition. Also continuous anti-bacterial potency of herbal eye drops was measured by the size of inhibition zone according to 2 days and 6 days culture each under the 50㎕condition. Results : 1. MIC on Staphylococcus aureus in Sean-tang, Jinpi-san and Tangpo-san was 100%, 20㎕. 2. MIC on Staphylococcus aureus in Coptidis rhizoma was 10%, 30㎕. 3. MIC on Staphylococcus aureus in Cravit was 0.1%, 50㎕. 4. Under the 2 days culture condition, the size of inhibition zone on Staphylococcus aureus by volume for Sean-tang was 12.0mm in 50㎕, Jinpi-san was 19.0mm in 50㎕, Tangpo-san was 15.0mm in 50㎕, Coptidis rhizoma was 32.7 mm in 50㎕and Cravit was 31mm in 50㎕, Coptidis rhizoma showed the highest anti-bacterial potency. 5. Under the 50㎕condition, the size of inhibition zone on Staphylococcus aureus by 2 and 6 culture days for Sean-tang was 12.0mm, Jinpi-san was 19.0mm, Tangpo-san was 15.0mm, Coptidis rhizoma was 32.7mm and Cravit was 31.0 mm, which showed sameness anti-bacterial potency in 2 days and 6 days. Conclusions : The present author think that the herbal eye drops can be used to cure Staphylococcus aureus keratitis and if further study is performed, the use of the herbal eye drops will be valuable and beneficial in the clinical medicines.

  14. The antimicrobial lysine-peptoid hybrid LP5 inhibits DNA replication and induces the SOS response in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Gottschalk, Sanne; Ifrah, Dan; Lerche, Sandra

    2013-01-01

    the growth of S. aureus without ATP leakage. Instead, LP5 bound DNA and inhibited macromolecular synthesis. The binding to DNA also led to inhibition of DNA gyrase and topoisomerase IV and caused induction of the SOS response. CONCLUSIONS: Our data demonstrate that LP5 may have a dual mode of action against...... S. aureus. At MIC concentrations, LP5 binds DNA and inhibits macromolecular synthesis and growth, whereas at concentrations above the MIC, LP5 targets the bacterial membrane leading to disruption of the membrane. These results add new information about the MOA of a new synthetic AMP and aid...... in the future design of synthetic peptides with increased therapeutic potential....

  15. Treatment of Staphylococcus aureus-induced chronic osteomyelitis with bone-like hydroxyapatite/poly amino acid loaded with rifapentine microspheres

    Science.gov (United States)

    Yan, Ling; Jiang, Dian-Ming; Cao, Zhi-Dong; Wu, Jun; Wang, Xin; Wang, Zheng-Long; Li, Ya-Jun; Yi, Yong-Fen

    2015-01-01

    Purpose The purpose of this study was to investigate the curative effect of bone-like hydroxyapatite/poly amino acid (BHA/PAA) as a carrier for poly(lactic-co-glycolic acid)-coated rifapentine microsphere (RPM) in the treatment of rabbit chronic osteomyelitis induced by Staphylococcus aureus. Methods RPM was prepared through an oil-in-water emulsion solvent evaporation method, and RPM was combined with BHA/PAA to obtain drug-loaded, slow-releasing materials. Twenty-six New Zealand white rabbits were induced to establish the animal model of chronic osteomyelitis. After debridement, the animals were randomly divided into three groups (n=8): the experimental group (with RPM-loaded BHA/PAA), the control group (with BHA/PAA), and the blank group. The RPM-loaded BHA/PAA was evaluated for antibacterial activity, dynamics of drug release, and osteogenic ability through in vitro and in vivo experiments. Results In vitro, RPM-loaded BHA/PAA released the antibiotics slowly, inhibiting the bacterial growth of S. aureus for up to 5 weeks. In vivo, at week 4, the bacterial colony count was significantly lower in the experimental group than in the control and blank groups (Posteomyelitis was cured and the bone defect was repaired in the experimental group, whereas the infection and bone defect persisted in the control and blank groups. Conclusion In vitro and in vivo experiments demonstrated that RPM-loaded BHA/PAA effectively cured S. aureus-induced chronic osteomyelitis. Therefore, BHA/PAA has potential value as a slow-releasing material in clinical setting. Further investigation is needed to determine the optimal dosage for loading rifapentine. PMID:26213463

  16. Treatment of localized abscesses induced by methicillin-resistant Staphylococcus aureus (MRSA) using MRgFUS: First in vivo results

    Science.gov (United States)

    Rieck, Birgit; Curiel, Laura; Mougenot, Charles; Zhang, Kunyan; Pichardo, Samuel

    2012-11-01

    Background. In the present work we study the therapeutic effect of focused ultrasound on localized abscess induced by methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a major nosocomial pathogen in health-care facilities. The people, particularly those who are immunocompromised are prone to develop infectious sites that often are non-responsive to regular treatments. Because of its capability to induce a rise of temperature at a very precise location, the use of focused ultrasound represents a considerable opportunity to propose a new therapy for MRSA-related infections. Methods. A 50μL subcutaneous injection of MRSA strain USA 400 bacteria at a concentration of 7×103/μL was made on the left thigh of BALB/c mice and an abscess of 6±2 mm-length formed after 48hrs. A transducer operating at 3 MHz with a focal length of 50mm and diameter of 32mm was used to treat the abscess. The focal point was positioned 2mm under the skin at the abscess center. Forty-eight hours after injection 4 ultrasound exposures of 9s-each were applied to each abscess under Magnetic Resonance-guidance. Each exposure was followed by a 1 min pause. Real-time estimation of change of temperature was done using a communication toolbox (matMRI) developed in our laboratory. Three experimental groups of 6 animals each were tested: moderate temperature (MT), high temperature (HT) and control. MT and HT groups reached, respectively, 55°C and 65°C at end of exposure. Effectiveness of the treatment was assessed by culturing bacteria of the treated abscess 1 and 4 days after treatment. Spleen samples were cultured to test for septicemia. Results. Macroscopic evaluation of treated abscess indicated a diminution of external size of abscess 1d after treatment. Treatment did not cause open wounds. Bacteria counting 1 day after treatment was 0.7±1.1 × 105, 0.5±0.7 × 105 and 1.1±2.3 × 105 CFU/μl for MT, HT and control groups, respectively; for the 4-day end point, the count was 0.6±0.6

  17. Immunization routes in cattle impact the levels and neutralizing capacity of antibodies induced against S. aureus immune evasion proteins

    NARCIS (Netherlands)

    Boerhout, Eveline; Vrieling, Manouk; Benedictus, Lindert; Daemen, Ineke; Ravesloot, Lars; Rutten, Victor; Nuijten, Piet; van Strijp, Jos; Koets, Ad; Eisenberg, Susanne

    2015-01-01

    Vaccines against S. aureus bovine mastitis are scarce and show limited protection only. All currently available vaccines are applied via the parenteral (usually intramuscular) route. It is unknown, however, whether this route is the most suitable to specifically increase intramammary immunity to

  18. Immunization routes in cattle impact the levels and neutralizing capacity of antibodies induced against S. aureus immune evasion proteins

    NARCIS (Netherlands)

    Boerhout, Eveline; Vrieling, Manouk; Benedictus, Lindert; Daemen, Ineke; Ravesloot, Lars; Rutten, Victor; Nuijten, Piet; Strijp, Van Jos; Koets, Ad; Eisenberg, Susanne

    2015-01-01

    Vaccines against S. aureus bovine mastitis are scarce and show limited protection only. All currently available vaccines are applied via the parenteral (usually intramuscular) route. It is unknown, however, whether this route is the most suitable to specifically increase intramammary immunity to

  19. Study of the humoral immunological response after vaccination with a Staphylococcus aureus biofilm-embedded bacterin in dairy cows: possible role of the exopolysaccharide specific antibody production in the protection from Staphylococcus aureus induced mastitis.

    Science.gov (United States)

    Prenafeta, Antoni; March, Ricard; Foix, Antoni; Casals, Isidre; Costa, Llorenç

    2010-04-15

    The objective of the present study was to analyze an extracellular component from Staphylococcus aureus (S. aureus), which we refer to as slime associated antigenic complex (SAAC), and to investigate the role of SAAC-specific antibody production in protection from S. aureus bovine mastitis. Twelve primiparous gestating cows were randomly assigned to one of the three groups: Group 1 was vaccinated with a S. aureus bacterin with very limited SAAC content; Group 2 received a S. aureus bacterin with high SAAC content and Group 3 served as unvaccinated controls. Animals were vaccinated at 45 days before the expected parturition date and revaccinated 35 days later. All groups were challenged by intramammary infusion with a virulent heterologous strain of S. aureus 23 days after calving. Antibody response against SAAC in serum and in milk, general clinical signs, mastitis score, somatic cell count (SCC) and count of S. aureus in milk were evaluated before and after challenge. Immunization with a high SAAC content in the S. aureus bacterin (Group 2) significantly enhanced antibody titers against SAAC (in serum and milk) and reduced the S. aureus concentration in milk during the post-challenge period compared to Group 1 and Group 3. Moreover, a significant negative correlation was observed between SAAC antibody production on the day of the challenge and the S. aureus count in milk by 1 day after challenge. However, there was no evidence of a difference between vaccinated and control groups with regard to clinical signs of mastitis following the challenge. Nevertheless, the SAAC antibody concentration on the day of the challenge negatively correlated with the mastitis score in quarters infected with S. aureus at 2 days post-challenge. These results indicate that the vaccines did not prevent S. aureus intramammary infection (IMI) after the experimental challenge, but immunization with a S. aureus bacterin with high SAAC content was able to reduce S. aureus multiplication in

  20. Mode of action of Buddleja cordata verbascoside against Staphylococcus aureus.

    Science.gov (United States)

    Avila, J G; de Liverant, J G; Martínez, A; Martínez, G; Muñoz, J L; Arciniegas, A; Romo de Vivar, A

    1999-07-01

    We evaluate the mode of action of verbascoside obtained from Buddleja cordata against Staphylococcus aureus by killing kinetics and incorporation of precursors methods. Verbascoside induced lethal effect on S. aureus, by affecting protein synthesis and inhibiting leucine incorporation.

  1. Focused ultrasound treatment of abscesses induced by methicillin resistant Staphylococcus aureus: Feasibility study in a mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Rieck, Birgit [Thunder Bay Regional Research Institute, Thunder Bay, Ontario P7B6V4 (Canada); Bates, David; Pichardo, Samuel, E-mail: spichard@lakeheadu.ca, E-mail: lcuriel@lakeheadu.ca; Curiel, Laura, E-mail: spichard@lakeheadu.ca, E-mail: lcuriel@lakeheadu.ca [Thunder Bay Regional Research Institute, Thunder Bay, Ontario P7B6V4, Canada and Lakehead University, Thunder Bay, Ontario P7B6V4 (Canada); Zhang, Kunyan [Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Escott, Nicholas [Department of Pathology, Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario P7B 6V4 (Canada); Mougenot, Charles [Philips Healthcare, Ontario L6C 2S3 (Canada)

    2014-06-15

    Purpose: To study the therapeutic effect of focused ultrasound on abscesses induced by methicillin-resistantStaphylococcus aureus (MRSA). MRSA is a major nosocomial pathogen where immunocompromised patients are prone to develop infections that are less and less responsive to regular treatments. Because of its capability to induce a rise of temperature at a very precise location, the use of focused ultrasound represents a considerable opportunity for therapy of localized MRSA-related infections. Methods: 50μl of MRSA strain USA400 bacteria suspension at a concentration of 1.32 ± 0.5 × 10{sup 5} colony forming units (cfu)/μl was injected subcutaneously in the left flank of BALB/c mice. An abscess of 6 ± 2 mm in diameter formed after 48 h. A transducer operating at 3 MHz with a focal length of 50 mm and diameter of 32 mm was used to treat the abscess. The focal point was positioned 2 mm under the skin at the abscess center. Forty-eight hours after injection four ultrasound exposures of 9 s each were applied to each abscess under magnetic resonance imaging guidance. Each exposure was followed by a 1 min pause. These parameters were based on preliminary experiments to ensure repetitive accurate heating of the abscess. Real-time estimation of change of temperature was done using water-proton resonance frequency and a communication toolbox (matMRI) developed inhouse. Three experimental groups of animals each were tested: control, moderate temperature (MT), and high temperature (HT). MT and HT groups reached, respectively, 52.3 ± 5.1 and 63.8 ± 7.5 °C at the end of exposure. Effectiveness of the treatment was assessed by evaluating the bacteria amount of the treated abscess 1 and 4 days after treatment. Myeloperoxidase (MPO) assay evaluating the neutrophil amount was performed to assess the local neutrophil recruitment and the white blood cell count was used to evaluate the systemic inflammatory response after focused ultrasound treatment. Results: Macroscopic

  2. A new preclinical approach for treating chronic osteomyelitis induced by Staphylococcus aureus: in vitro and in vivo study on photodynamic antimicrobial therapy (PAmT).

    Science.gov (United States)

    dos Reis, João Alves; de Carvalho, Fabíola Bastos; Trindade, Renan Ferreira; de Assis, Patrícia Nascimento; de Almeida, Paulo Fernando; Pinheiro, Antônio Luiz Barbosa

    2014-03-01

    Osteomyelitis is an acute or chronic inflammation in the marrow spaces in the superficial or cortical bone, and can be associated with bacterial or fungal infections. Chronic osteomyelitis represents a major health problem due to its difficult treatment and increased morbidity. Photodynamic antimicrobial therapy (PAmT) is a treatment based on a cytotoxic photochemical reaction in which a bright light produced by a laser system and an active photosensitizer absorbed by cells leads to a process of activation that induces a series of metabolic reactions that culminates a bacterial killing. The aim of the present randomized study was to evaluate, by in vitro and in vivo microbiological analysis, the effects of PAmT on tibial surgical bone defects in rats infected by Staphylococcus aureus using bacterial counts carried out immediately and after 30 days after treatment as outcome measure. In the preliminary in vitro study, a diode laser (λ660 nm; 40 mW; ϕ = 0.4 cm(2); 5 or 10 J/cm(2)) and 5, 10, and 15 μg/mL toluidine blue were tested, and the best parameter was chosen for the in vivo study. The concentration of 5 μg/mL was selected to perform the decontamination of S. aureus-infected tibial bone defects in rats. The findings were subjected to statistical analysis. For all PAmTs groups, with the different concentrations, treatment showed significant reductions (p < 0.001) in the amount of bacteria. The in vivo study PAmT group presented a bacterial reduction of 97.4% (p < 0.001). The PAmT using toluidine blue was effective in reducing the number of S. aureus in both in vitro and in vivo studies.

  3. Methicillin-resistant staphylococcus aureus (MRSA) colonization ...

    African Journals Online (AJOL)

    Introduction: methicillin-resistant Staphylococcus aureus (MRSA) has been recognized as important nosocomial pathogens worldwide. S aureus may induce clinically manifested diseases, or the host may remain completely asymptomatic. Methods: a cross-sectional hospital-based study was conducted from October 2012 ...

  4. Thioridazine Induces Major Changes in Global Gene Expression and Cell Wall Composition in Methicillin-Resistant Staphylococcus aureus USA300

    DEFF Research Database (Denmark)

    Thorsing, Mette; Klitgaard, Janne Kudsk; Atilano, Magda L.

    2013-01-01

    and the transcriptomic response of S. aureus to known inhibitors of cell wall synthesis suggests that TDZ disturbs PGN biosynthesis at a stage that precedes transpeptidation by penicillin-binding proteins (PBPs). In support of this notion, dramatic changes in the muropeptide profile of USA300 were observed following...... of peptidoglycan (PGN) synthesis. Furthermore, our microarray analysis demonstrates that TDZ modulates the expression of genes encoding membrane and surface proteins, transporters, and enzymes involved in amino acid biosynthesis. Interestingly, resemblance between the transcriptional profile of TDZ treatment...

  5. Efficacy of Primary Collagen Cross-Linking with Photoactivated Chromophore (PACK-CXL) for the Treatment of Staphylococcus aureus-Induced Corneal Ulcers.

    Science.gov (United States)

    Tal, Kfir; Gal-Or, Orly; Pillar, Shani; Zahavi, Alon; Rock, Oded; Bahar, Irit

    2015-10-01

    To evaluate the efficacy of corneal collagen cross-linking (CXL) with photoactivated riboflavin (PACK-CXL) as primary therapy for Staphylococcus aureus-induced corneal ulcers in a rabbit model. The right eye of 40 rabbits was inoculated with S. aureus to induce formation of central corneal ulcers (day 1). The ulcer was examined on day 5, and rabbits were randomly assigned to 4 groups-group A: no treatment (control); group B: topical antibiotic treatment (cefazolin 50 mg/mL, garamycin 14 mg/mL drops, chloramphenicol 5% ointment every 2 hours); group C: PACK-CXL; group D: PACK-CXL + topical antibiotics. Follow-up by biomicroscopy was performed on day 5 and then every week for 1 month. The main outcome measures included infiltrates or the scar diameter, time to healing, time to full epithelialization, and a change in corneal thickness. After 1 month of treatment, group C ulcers had the smallest mean scar diameter (8.8 mm), followed by groups D (11.2 mm), B (13.0 mm), and A (24.5 mm) (P = 0.011). Group C had the shortest mean healing time (15.5 days), followed by groups D (17.2 days), B (19.7 days), and A (21.8 days). Analysis of relative reduction in the infiltrate size from day 5 yielded better results for groups C (P = 0.039) and D (P = 0.034) than those of group B. We demonstrate a beneficial effect of PACK-CXL as primary treatment, either as stand-alone or as an adjuvant to antimicrobial therapy.

  6. Surface plasmon resonance-induced photoactivation of gold nanoparticles as bactericidal agents against methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Mocan, Lucian; Ilie, Ioana; Matea, Cristian; Tabaran, Flaviu; Kalman, Ersjebet; Iancu, Cornel; Mocan, Teodora

    2014-01-01

    Systemic infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and other bacteria are responsible for millions of deaths worldwide, and much of this mortality is due to the rise of antibiotic-resistant organisms as a result of natural selection. Gold nanoparticles synthesized using the standard wet chemical procedure were photoexcited using an 808 nm 2 W laser diode and further administered to MRSA bacteria. Flow cytometry, transmission electron microscopy, contrast phase microscopy, and fluorescence microscopy combined with immunochemical staining were used to examine the interaction of the photoexcited gold nano-particles with MRSA bacteria. We show here that phonon-phonon interactions following laser photoexcitation of gold nanoparticles exhibit increased MRSA necrotic rates at low concentrations and short incubation times compared with MRSA treated with gold nanoparticles alone. These unique data may represent a step forward in the study of bactericidal effects of various nanomaterials, with applications in biology and medicine.

  7. Cloxacillin control of experimental arthritis induced by SEC(+) Staphylococcus aureus is associated with downmodulation of local and systemic cytokines.

    Science.gov (United States)

    Colavite, Priscila Maria; Ishikawa, Larissa Lumi Watanabe; Zorzella-Pezavento, Sofia Fernanda Gonçalves; Oliveira, Larissa Ragozo Cardoso de; França, Thaís Graziela Donegá; da Rosa, Larissa Camargo; Chiuso-Minicucci, Fernanda; Vieira, Andreia Espíndola; Francisconi, Carolina Fávaro; da Cunha, Maria de Lourdes Ribeiro de Souza; Garlet, Gustavo Pompermaier; Sartori, Alexandrina

    2016-07-01

    Staphylococcus aureus is the most common agent of septic arthritis (SA) that is a severe, rapidly progressive and erosive disease. In this work we investigated the clinical, histopathological and immunological characteristics of the SA triggered by an enterotoxin C producer S. aureus strain. The effect of a β-lactamic antibiotic over disease evolution and cytokine production was also evaluated. After confirmation that ATCC 19095 SEC(+) strain preserved its ability to produce enterotoxin C, this bacteria was used to infect C57BL/6 male mice. Body weight, clinical score and disease prevalence were daily evaluated during 14 days. Cytokine production by splenocytes, cytokine mRNA expression in arthritic lesions, transcription factors mRNA expression in inguinal lymph nodes and histopathological analysis were performed 7 and 14 days after infection. ATCC 19095 SEC(+) strain caused a severe arthritis characterized by weight loss, high clinical scores and a 100% disease prevalence. Histopathological analysis revealed inflammation, pannus formation and bone erosion. Arthritis aggravation was associated with elevated production of pro-inflammatory cytokines, higher local mRNA expression of these cytokines and also higher mRNA expression of T-bet, ROR-γ and GATA-3. Disease control by cloxacillin was associated with decreased production of pro-inflammatory cytokines but not of IL-10. These findings indicate that the ATCC 19095 SEC(+) strain is able to initiate a severe septic arthritis in mice associated with elevated cytokine production that can be, however, controlled by cloxacillin. © 2015 John Wiley & Sons Ltd.

  8. Virulence factors of Staphylococcus aureus induce Erk-MAP kinase activation and c-Fos expression in S9 and 16HBE14o- human airway epithelial cells.

    Science.gov (United States)

    Below, Sabine; Konkel, Anne; Zeeck, Cathrin; Müller, Christian; Kohler, Christian; Engelmann, Susanne; Hildebrandt, Jan-Peter

    2009-03-01

    Part of the innate defense of bronchial epithelia against bacterial colonization is regulated secretion of salt, water, and mucus as well as defensins and cytokines involving MAP kinase activation and alterations in early gene expression. We tested two different types of immortalized human airway epithelial cells (S9, 16HBE14o-) for activation of Erk-type MAP kinases and for expression of c-Fos on treatment with Staphylococcus aureus culture supernatants from the stationary growth phase [optical density (OD)(540 nm) = 10] or with recombinant S. aureus hemolysins A and B (Hla, Hlb). OD10 supernatants activated Erk-type MAP kinases and c-Fos expression in a concentration-dependent manner. Hla induced Erk-type kinase phosphorylation in S9 but not in 16HBE14o- cells. Hlb induced Erk activation in either cell type. Basal and stimulated levels of Erk-type MAP kinase phosphorylation were sensitive to the Mek1 inhibitor PD-98059, indicating that the bacterial products activated the entire signaling cascade that coregulates IL-8 induction and secretion. While c-Fos expression was enhanced by OD10 supernatants, Hla, and Hlb in S9 cells, 16HBE14o- cells responded to OD10 supernatant and Hlb but not to Hla. In S9 cells, PD-98059 suppressed c-Fos upregulation by OD10 supernatant, Hla, or Hlb, indicating that c-Fos expression requires activation of Erk-type MAP kinases. In 16HBE14o- cells, however, c-Fos expression by OD10 supernatant was sensitive to PD-98059, while that induced by Hlb was not. This indicates that ingredients of OD10 supernatants other than Hla or Hlb are activating Erk-type MAP kinases in 16HBE14o- cells and that other intracellular signaling systems apart from Erk-type MAP kinases contribute to Hlb-mediated regulation of c-Fos. Thus interaction of bacterial factors with airway epithelial cells may be highly cell type specific.

  9. Beneficial Effects of Exogenous Melatonin in Acute Staphylococcus aureus and Escherichia coli Infection-Induced Inflammation and Associated Behavioral Response in Mice After Exposure to Short Photoperiod.

    Science.gov (United States)

    Bishayi, Biswadev; Adhikary, Rana; Nandi, Ajeya; Sultana, Sahin

    2016-12-01

    The administration of melatonin during acute bacterial infection was evaluated in this study. Mice pre-exposed to normal photoperiodic (NP), short photoperiodic (SP), and long photoperiodic (LP) day lengths were infected separately with live Staphylococcus aureus (5 × 10 6 cells/ml) or Escherichia coli (2.5 × 10 7 colony-forming units/ml) and treated with melatonin (10 mg/kg body weight). Behavioral studies were performed before bacterial infection and after melatonin administration. In mice pre-exposed to SP, exogenous melatonin administration resulted in better clearance of bacteria from blood and behavioral improvement. Reduced glutathione content and superoxide dismutase activities were increased, with concomitant decrease in lipid peroxidation content and catalase activities in the liver, brain, and spleen after exogenous melatonin administration. The overproduction of tumor necrosis factor-α, interferon-γ, and interleukin-6 during acute bacterial infection in mice exposed to different photoperiods was probably regulated by the administration of exogenous melatonin, by reducing neutrophil recruitment to spleen, expression of inducible nitric oxide synthase and cyclooxygenase-2 in hypothalamus, and C-reactive protein in the serum, and was also associated with improved behavioral response. Photoperiodic variations in inflammatory and oxidative stress markers might be correlated to serum melatonin and corticosterone levels. This study suggests that the administration of melatonin during SP exposure is protective in infection-induced inflammation than NP and LP exposure.

  10. Staphylococcus aureus alpha-toxin induces apoptosis in peripheral blood mononuclear cells : role of endogenous tumour necrosis factor-alpha and the mitochondrial death pathway

    NARCIS (Netherlands)

    Haslinger, Bettina; Strangfeld, Katrin; Peters, Georg; Schulze-Osthoff, Klaus; Sinha, Bhanu

    2003-01-01

    Staphylococcus aureus infections can result in septic and toxic shock with depletion of immune cells and massive cytokine production. Recently, we showed that, in S. aureus-infected Jurkat T cells, alpha-toxin is the major mediator of caspase activation and apoptosis. Here, we investigated the

  11. MF59- and Al(OH)3-Adjuvanted Staphylococcus aureus (4C-Staph) Vaccines Induce Sustained Protective Humoral and Cellular Immune Responses, with a Critical Role for Effector CD4 T Cells at Low Antibody Titers

    Science.gov (United States)

    Monaci, Elisabetta; Mancini, Francesca; Lofano, Giuseppe; Bacconi, Marta; Tavarini, Simona; Sammicheli, Chiara; Arcidiacono, Letizia; Giraldi, Monica; Galletti, Bruno; Rossi Paccani, Silvia; Torre, Antonina; Fontana, Maria Rita; Grandi, Guido; de Gregorio, Ennio; Bensi, Giuliano; Chiarot, Emiliano; Nuti, Sandra; Bagnoli, Fabio; Soldaini, Elisabetta; Bertholet, Sylvie

    2015-01-01

    Staphylococcus aureus (S. aureus) is an important opportunistic pathogen that may cause invasive life-threatening infections, like sepsis and pneumonia. Due to the increasing antibiotic resistance, the development of an effective vaccine against S. aureus is needed. Although a correlate of protection against staphylococcal diseases is not yet established, several findings suggest that both antibodies and CD4 T cells might contribute to optimal immunity. In this study, we show that adjuvanting a multivalent vaccine (4C-Staph) with MF59, an oil-in-water emulsion licensed in human vaccines, further potentiated antigen-specific IgG titers and CD4 T-cell responses compared to alum and conferred protection in the peritonitis model of S. aureus infection. Moreover, we showed that MF59- and alum-adjuvanted 4C-Staph vaccines induced persistent antigen-specific humoral and T-cell responses, and protected mice from infection up to 4 months after immunization. Furthermore, 4C-Staph formulated with MF59 was used to investigate which immune compartment is involved in vaccine-induced protection. Using CD4 T cell-depleted mice or B cell-deficient mice, we demonstrated that both T and B-cell responses contributed to 4C-Staph vaccine-mediated protective immunity. However, the role of CD4 T cells seemed more evident in the presence of low-antibody responses. This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen. PMID:26441955

  12. MF59- and Al(OH3-adjuvanted Staphylococcus aureus (4C-Staph vaccines induce sustained protective humoral and cellular immune responses, with a critical role for effector CD4 T cells at low antibody titers.

    Directory of Open Access Journals (Sweden)

    Elisabetta eMonaci

    2015-09-01

    Full Text Available Staphylococcus aureus (S. aureus is an important opportunistic pathogen that may cause invasive life-threatening infections like sepsis and pneumonia. Due to increasing antibiotic-resistance, the development of an effective vaccine against S. aureus is needed. Although a correlate of protection against staphylococcal diseases is not yet established, several findings suggest that both antibodies and CD4 T cells might contribute to optimal immunity. In this study, we show that adjuvanting a multivalent vaccine (4C-Staph with MF59, an oil-in-water emulsion licensed in human vaccines, further potentiated antigen-specific IgG titers and CD4 T cell responses compared to alum and conferred protection in the peritonitis model of S. aureus infection. Moreover, we showed that MF59- and alum-adjuvanted 4C-Staph vaccines induced persistent antigen-specific humoral and T cell responses, and protected mice from infection up to 4 months after immunization. Furthermore, 4C-Staph formulated with MF59 was used to investigate which immune compartment is involved in vaccine-induced protection. Using CD4 T cell-depleted mice or B cell deficient mice, we demonstrated that both T and B cell responses contributed to 4C-Staph vaccine-mediated protective immunity. However, the role of CD4 T cells seemed more evident in the presence of low antibody responses. This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen.

  13. Staphylococcus aureus and Pregnancy

    Science.gov (United States)

    Staphylococcus aureus (Staph Infection) In every pregnancy, a woman starts out with a 3-5% chance of having a baby with ... from your health care provider. What is a staph infection? Staphylococcus aureus (staph) is a type of ...

  14. A Novel Porcine Model of Septic Shock Induced by Acute Respiratory Distress Syndrome due to Methicillin-resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Shuo Wang

    2017-01-01

    Conclusions: In the present study, we developed a novel porcine model of septic shock induced by ARDS due to severe MRSA pneumonia with characteristic hyperdynamic and hypodynamic phases in 24 h, which mimicked the hemodynamic changing of septic shock in human.

  15. Staphylococcus aureus toxins.

    Science.gov (United States)

    Otto, Michael

    2014-02-01

    Staphylococcus aureus is a dangerous pathogen that causes a variety of severe diseases. The virulence of S. aureus is defined by a large repertoire of virulence factors, among which secreted toxins play a preeminent role. Many S. aureus toxins damage biological membranes, leading to cell death. In particular, S. aureus produces potent hemolysins and leukotoxins. Among the latter, some were recently identified to lyse neutrophils after ingestion, representing an especially powerful weapon against bacterial elimination by innate host defense. Furthermore, S. aureus secretes many factors that inhibit the complement cascade or prevent recognition by host defenses. Several further toxins add to this multi-faceted program of S. aureus to evade elimination in the host. This review will give an overview over S. aureus toxins focusing on recent advances in our understanding of how leukotoxins work in receptor-mediated or receptor-independent fashions. Published by Elsevier Ltd.

  16. Efficacy of linezolid compared to vancomycin in an experimental model of pneumonia induced by methicillin-resistant Staphylococcus aureus in ventilated pigs.

    Science.gov (United States)

    Martinez-Olondris, Pilar; Rigol, Montserrat; Soy, Dolors; Guerrero, Laura; Agusti, Carlos; Quera, Maria Angels; Li Bassi, Gianluigi; Esperatti, Mariano; Luque, Nestor; Liapikou, Manto; Filella, Xavier; Marco, Francesc; de la Bellacasa, Jordi Puig; Torres, Antoni

    2012-01-01

    To assess the efficacy of linezolid compared with vancomycin in an experimental model of pneumonia induced by methicillin-resistant Staphylococcus aureus (MRSA) in ventilated pigs. Forty pigs (30 kg) were intubated and challenged via bronchoscopy with a suspension of 106 colony forming units of MRSA into every lobe. Afterwards, pigs were ventilated up to 96 hours. Twelve hours after bacterial inoculation, the animals were randomized into 4 groups of treatment: group 1, control; group 2, vancomycin twice daily; group 3, continuous infusion of vancomycin; and group 4, linezolid. Clinical and laboratory parameters were monitored throughout the study. Bacterial cultures of bronchoalveolar lavage fluid and lung tissue samples were performed at the end of the study. Measurements of histopathology derangements of lung samples and studies of intrapulmonary drug penetration were performed. A total of 34 animals completed the study. No differences in clinical and laboratory parameters were observed. The percentage of bronchoalveolar lavage fluid and lung tissue samples with positive cultures for MRSA in controls and groups 2, 3, and 4 was respectively 75%, 11%, 11%, and 0% (p < .01); 52%, 9%, 24%, and 2.5% (p < .01). Histopathology studies demonstrated signs of pneumonia in 95%, 69%, 58%, and 57% and signs of severe pneumonia in 48%, 29%, 22%, and 0% of controls and groups 2, 3, and 4, respectively (p < .01). In addition, pharmacokinetics/pharmacodynamics profile in serum and lung tissue showed better results for linezolid compared with both vancomycin treatments. In this animal model of MRSA pneumonia, linezolid showed a better efficacy than vancomycin showed because of a better pharmacokinetics/pharmacodynamics index.

  17. A porcine model of haematogenous brain infectionwith staphylococcus aureus

    DEFF Research Database (Denmark)

    Astrup, Lærke Boye; Agerholm, Jørgen Steen; Nielsen, Ole Lerberg

    2012-01-01

    A PORCINE MODEL OF HAEMATOGENOUS BRAIN INFECTION WITH STAPHYLOCOCCUS AUREUS Astrup Lærke1, Agerholm Jørgen1, Nielsen Ole1, Jensen Henrik1, Leifsson Páll1, Iburg Tine2. 1: Faculty of Health and Medical Sciences, University of Copenhagen, Denmark boye@life.ku.dk 2: National Veterinary Institute......, Uppsala, Sweden Introduction Staphylococcus aureus (S.aureus) is a common cause of sepsis and brain abscesses in man and a frequent cause of porcine pyaemia. Here we present a porcine model of haematogenous S. aureus-induced brain infection. Materials and Methods Four pigs had two intravenous catheters...

  18. Utility of (11)C-methionine and (11)C-donepezil for imaging of Staphylococcus aureus induced osteomyelitis in a juvenile porcine model

    DEFF Research Database (Denmark)

    Afzelius, Pia; Alstrup, Aage Ko; Schønheyder, Henrik C

    2016-01-01

    in the right femoral artery with a porcine strain of Staphylococcus aureus. The sequential scan protocol included Computed Tomography, (11)C-methionine and (11)C-donepezil PET, (99m) Tc-DPD and (111)In-labelled leukocytes scintigraphy, and (18)F-FDG PET. This was followed by necropsy of the pigs and gross...

  19. Host Physiologic Changes Induced by Influenza A Virus Lead to Staphylococcus aureus Biofilm Dispersion and Transition from Asymptomatic Colonization to Invasive Disease

    Directory of Open Access Journals (Sweden)

    Ryan M. Reddinger

    2016-08-01

    Full Text Available Staphylococcus aureus is a ubiquitous opportunistic human pathogen and a major health concern worldwide, causing a wide variety of diseases from mild skin infections to systemic disease. S. aureus is a major source of severe secondary bacterial pneumonia after influenza A virus infection, which causes widespread morbidity and mortality. While the phenomenon of secondary bacterial pneumonia is well established, the mechanisms behind the transition from asymptomatic colonization to invasive staphylococcal disease following viral infection remains unknown. In this report, we have shown that S. aureus biofilms, grown on an upper respiratory epithelial substratum, disperse in response to host physiologic changes related to viral infection, such as febrile range temperatures, exogenous ATP, norepinephrine, and increased glucose. Mice that were colonized with S. aureus and subsequently exposed to these physiologic stimuli or influenza A virus coinfection developed pronounced pneumonia. This study provides novel insight into the transition from colonization to invasive disease, providing a better understanding of the events involved in the pathogenesis of secondary staphylococcal pneumonia.

  20. Exposure to sub-inhibitory concentrations of gentamicin, ciprofloxacin and cefotaxime induces multidrug resistance and reactive oxygen species generation in meticillin-sensitive Staphylococcus aureus.

    Science.gov (United States)

    Bhattacharya, Gargi; Dey, Diganta; Das, Satadal; Banerjee, Abhijit

    2017-06-01

    The role of antibiotics below their MIC in the development of bacterial drug resistance is becoming increasingly important. We investigated the effect of sub-MICs of bactericidal antibiotics on the susceptibility pattern of Staphylococcus aureus and evaluated the role of free radicals. A total of 12 S. aureus strains were recovered from pus samples and their antibiograms determined. The test isolates were treated with sub-MIC levels of tetracycline, gentamicin, ciprofloxacin and cefotaxime. Alterations in their respective breakpoints were observed along with measurements of free radical generation by nitro blue tetrazolium test.Results/Key findings. Gentamicin, ciprofloxacin and cefotaxime exposure significantly altered the breakpoints of exposed isolates against several tested antibiotics and higher levels of free radicals were generated after antibiotic exposure. Our study demonstrates that sub-MIC levels of antimicrobials can lead to resistance and cross-resistance across several classes of antibiotics in wild strains of S. aureus, possibly by free radical production. The molecular mechanisms behind the acquisition of drug resistance at low antibiotic concentrations and the specific target genes of reactive oxygen speciesneed to be explored further.

  1. Genomic analysis of an emerging multiresistant Staphylococcus aureus strain rapidly spreading in cystic fibrosis patients revealed the presence of an antibiotic inducible bacteriophage

    Directory of Open Access Journals (Sweden)

    Boniface Stephanie

    2009-01-01

    Full Text Available Abstract Background Staphylococcus aureus is a major human pathogen responsible for a variety of nosocomial and community-acquired infections. Recent reports show that the prevalence of Methicillin-Resistant S. aureus (MRSA infections in cystic fibrosis (CF patients is increasing. In 2006 in Marseille, France, we have detected an atypical MRSA strain with a specific antibiotic susceptibility profile and a unique growth phenotype. Because of the clinical importance of the spread of such strain among CF patients we decided to sequence the genome of one representative isolate (strain CF-Marseille to compare this to the published genome sequences. We also conducted a retrospective epidemiological analysis on all S. aureus isolated from 2002 to 2007 in CF patients from our institution. Results CF-Marseille is multidrug resistant, has a hetero-Glycopeptide-Intermediate resistance S. aureus phenotype, grows on Cepacia agar with intense orange pigmentation and has a thickened cell wall. Phylogenetic analyses using Complete Genome Hybridization and Multi Locus VNTR Assay showed that CF-Marseille was closely related to strain Mu50, representing vancomycin-resistant S. aureus. Analysis of CF-Marseille shows a similar core genome to that of previously sequenced MRSA strains but with a different genomic organization due to the presence of specific mobile genetic elements i.e. a new SCCmec type IV mosaic cassette that has integrated the pUB110 plasmid, and a new phage closely related to phiETA3. Moreover this phage could be seen by electron microscopy when mobilized with several antibiotics commonly used in CF patients including, tobramycin, ciprofloxacin, cotrimoxazole, or imipenem. Phylogenetic analysis of phenotypically similar h-GISA in our study also suggests that CF patients are colonized by polyclonal populations of MRSA that represents an incredible reservoir for lateral gene transfer. Conclusion In conclusion, we demonstrated the emergence and

  2. Mechanism of activation of human basophils by Staphylococcus aureus Cowan 1.

    OpenAIRE

    Marone, G; Tamburini, M; Giudizi, M G; Biagiotti, R; Almerigogna, F; Romagnani, S

    1987-01-01

    We investigated the capacity of Staphylococcus aureus Cowan 1 and S. aureus Wood 46 to induce histamine release from human basophils in vitro. S. aureus Cowan 1 (10(5) to 10(7)/ml), which synthesizes protein A (Staph A), stimulated the release of histamine from basophils, whereas S. aureus Wood 46 (10(5) to 2 X 10(7)/ml), which does not synthesize Staph A, did not induce histamine secretion. Soluble Staph A (10(-3) to 10 micrograms/ml), but not staphylococcal enterotoxin A, induced histamine ...

  3. Memory Th1 Cells Are Protective in Invasive Staphylococcus aureus Infection.

    LENUS (Irish Health Repository)

    Brown, Aisling F

    2015-01-01

    Mechanisms of protective immunity to Staphylococcus aureus infection in humans remain elusive. While the importance of cellular immunity has been shown in mice, T cell responses in humans have not been characterised. Using a murine model of recurrent S. aureus peritonitis, we demonstrated that prior exposure to S. aureus enhanced IFNγ responses upon subsequent infection, while adoptive transfer of S. aureus antigen-specific Th1 cells was protective in naïve mice. Translating these findings, we found that S. aureus antigen-specific Th1 cells were also significantly expanded during human S. aureus bloodstream infection (BSI). These Th1 cells were CD45RO+, indicative of a memory phenotype. Thus, exposure to S. aureus induces memory Th1 cells in mice and humans, identifying Th1 cells as potential S. aureus vaccine targets. Consequently, we developed a model vaccine comprising staphylococcal clumping factor A, which we demonstrate to be an effective human T cell antigen, combined with the Th1-driving adjuvant CpG. This novel Th1-inducing vaccine conferred significant protection during S. aureus infection in mice. This study notably advances our understanding of S. aureus cellular immunity, and demonstrates for the first time that a correlate of S. aureus protective immunity identified in mice may be relevant in humans.

  4. Memory Th1 Cells Are Protective in Invasive Staphylococcus aureus Infection.

    Directory of Open Access Journals (Sweden)

    Aisling F Brown

    Full Text Available Mechanisms of protective immunity to Staphylococcus aureus infection in humans remain elusive. While the importance of cellular immunity has been shown in mice, T cell responses in humans have not been characterised. Using a murine model of recurrent S. aureus peritonitis, we demonstrated that prior exposure to S. aureus enhanced IFNγ responses upon subsequent infection, while adoptive transfer of S. aureus antigen-specific Th1 cells was protective in naïve mice. Translating these findings, we found that S. aureus antigen-specific Th1 cells were also significantly expanded during human S. aureus bloodstream infection (BSI. These Th1 cells were CD45RO+, indicative of a memory phenotype. Thus, exposure to S. aureus induces memory Th1 cells in mice and humans, identifying Th1 cells as potential S. aureus vaccine targets. Consequently, we developed a model vaccine comprising staphylococcal clumping factor A, which we demonstrate to be an effective human T cell antigen, combined with the Th1-driving adjuvant CpG. This novel Th1-inducing vaccine conferred significant protection during S. aureus infection in mice. This study notably advances our understanding of S. aureus cellular immunity, and demonstrates for the first time that a correlate of S. aureus protective immunity identified in mice may be relevant in humans.

  5. Memory Th1 Cells Are Protective in Invasive Staphylococcus aureus Infection

    Science.gov (United States)

    Lalor, Stephen J.; Leech, John M.; O’Keeffe, Kate M.; Mac Aogáin, Micheál; O’Halloran, Dara P.; Lacey, Keenan A.; Tavakol, Mehri; Hearnden, Claire H.; Fitzgerald-Hughes, Deirdre; Humphreys, Hilary; Fennell, Jérôme P.; van Wamel, Willem J.; Foster, Timothy J.; Geoghegan, Joan A.; Lavelle, Ed C.; Rogers, Thomas R.; McLoughlin, Rachel M.

    2015-01-01

    Mechanisms of protective immunity to Staphylococcus aureus infection in humans remain elusive. While the importance of cellular immunity has been shown in mice, T cell responses in humans have not been characterised. Using a murine model of recurrent S. aureus peritonitis, we demonstrated that prior exposure to S. aureus enhanced IFNγ responses upon subsequent infection, while adoptive transfer of S. aureus antigen-specific Th1 cells was protective in naïve mice. Translating these findings, we found that S. aureus antigen-specific Th1 cells were also significantly expanded during human S. aureus bloodstream infection (BSI). These Th1 cells were CD45RO+, indicative of a memory phenotype. Thus, exposure to S. aureus induces memory Th1 cells in mice and humans, identifying Th1 cells as potential S. aureus vaccine targets. Consequently, we developed a model vaccine comprising staphylococcal clumping factor A, which we demonstrate to be an effective human T cell antigen, combined with the Th1-driving adjuvant CpG. This novel Th1-inducing vaccine conferred significant protection during S. aureus infection in mice. This study notably advances our understanding of S. aureus cellular immunity, and demonstrates for the first time that a correlate of S. aureus protective immunity identified in mice may be relevant in humans. PMID:26539822

  6. The evolution of Staphylococcus aureus

    NARCIS (Netherlands)

    Deurenberg, Ruud H; Stobberingh, Ellen E

    2008-01-01

    A broad variety of infections, ranging from minor infections of the skin to post-operative wound infections can be caused by Staphylococcus aureus. The adaptive power of S. aureus to antibiotics leaded, in the early 1960s, to the emergence of methicillin-resistant S. aureus (MRSA). The cause of

  7. Utility of (11)C-methionine and (11)C-donepezil for imaging of Staphylococcus aureus induced osteomyelitis in a juvenile porcine model

    DEFF Research Database (Denmark)

    Afzelius, Pia; Alstrup, Aage Ko; Schønheyder, Henrik C

    2016-01-01

    The aim of this study was to compare (11)C-methionine and (11)C-donepezil positron emission tomography (PET) with (111)In-labeled leukocyte and (99m) Tc-DPD (Tc-99m 3,3-diphosphono-1,2-propanedicarboxylic acid) single-photon emission computed tomography (SPECT), and (18)F-fluorodeoxyglucose ((18)F...... in the right femoral artery with a porcine strain of Staphylococcus aureus. The sequential scan protocol included Computed Tomography, (11)C-methionine and (11)C-donepezil PET, (99m) Tc-DPD and (111)In-labelled leukocytes scintigraphy, and (18)F-FDG PET. This was followed by necropsy of the pigs and gross......-methionine in 79%, (11)C-donepezil in 58%, and (99m) Tc-DPD in none. Overall, (18)F-FDG PET was superior to (111)In-leukocyte SPECT and (11)C-methionine in marking infectious lesions....

  8. Staphylococcus aureus CC398

    DEFF Research Database (Denmark)

    Price, Lance B.; Stegger, Marc; Hasman, Henrik

    2012-01-01

    Since its discovery in the early 2000s, methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 (CC398) has become a rapidly emerging cause of human infections, most often associated with livestock exposure. We applied whole-genome sequence typing to characterize a diverse collectio...

  9. Antibiotic-mediated selection of quorum-sensing-negative Staphylococcus aureus

    DEFF Research Database (Denmark)

    Paulander, Wilhelm Erik Axel; Varming, Anders Nissen; Bæk, Kristoffer Torbjørn

    2012-01-01

    -acquired S. aureus infections and suggest that the adaptability of S. aureus to antibiotics involves the agr locus. IMPORTANCE: Staphylococcus aureus is the most frequently isolated pathogen in intensive care units and a common cause of nosocomial infections, resulting in a high degree of morbidity......Staphylococcus aureus is a human commensal that at times turns into a serious bacterial pathogen causing life-threatening infections. For the delicate control of virulence, S. aureus employs the agr quorum-sensing system that, via the intracellular effector molecule RNAIII, regulates virulence gene...... increases the agr-mediated fitness cost by inducing the expression of RNAIII. Thus, the extensive use of antibiotics in hospitals may explain why agr-negative variants are frequently isolated from hospital-acquired S. aureus infections but rarely found among community-acquired S. aureus strains. Importantly...

  10. Prophylactic effect of bacteriophages on mice subjected to chemotherapy-induced immunosuppression and bone marrow transplant upon infection with Staphylococcus aureus.

    Science.gov (United States)

    Zimecki, Michał; Artym, Jolanta; Kocieba, Maja; Weber-Dabrowska, Beata; Borysowski, Jan; Górski, Andrzej

    2010-05-01

    Due to the increased resistance of bacteria to antibiotics, phage therapy may be an alternative to treat or prevent suppurative infections in immunocompromised patients. The authors' recent studies indicated that such an approach is particularly beneficial in immunosuppressed mice. A5/L bacteriophages, specific for the Staphylococcus aureus strain L, were tested for their ability to protect CBA mice subjected to myeloablative (busulfan) and immunosuppressive (cyclophosphamide) conditioning followed by a syngeneic bone marrow transplantation (BMT) and infected with a sublethal or lethal dose of bacteria. The application of phages to immunocompromised mice given BMT led to a significant (>90%) reduction in bacterial load in the spleen and liver. Moreover, 72% of such mice attained long-term survival versus 8.2% survival of mice not treated with phages. Analysis of leukocyte number and blood cell type composition revealed that phage application increased the leukocyte numbers and neutrophil content in the circulating blood. Moreover, phage application led to an increased content of the myelocytic cell lineage in the bone marrow. The protective effects of phages in immunosuppressed mice are both direct (bacteriolytic) and indirect (by stimulation of myelopoiesis). The results suggest a potential benefit of phage therapy in immunocompromised patients subjected to bone marrow transplant procedures.

  11. Azoreductase in Staphylococcus aureus.

    Science.gov (United States)

    Zou, Wen; Cerniglia, Carl E; Chen, Huizhong

    2009-01-01

    Azoreductase(s) catalyze a NAD(P)H-dependent reaction in bacteria to metabolize azo dyes to colorless aromatic amines. Azoreductases from bacteria represent a novel family of enzymes with little similarity to other reductases. This unit will describe the current methods for measuring azoreductase from Staphylococcus aureus, which has been suggested to serve as a model strain to study the azo dye degradation by human skin microflora.

  12. "Gesundheit!" sneezing, common colds, allergies, and Staphylococcus aureus dispersion.

    Science.gov (United States)

    Bischoff, Werner E; Wallis, Michelle L; Tucker, Brian K; Reboussin, Beth A; Pfaller, Michael A; Hayden, Frederick G; Sherertz, Robert J

    2006-10-15

    Staphylococcus aureus is among the most important pathogens in today's hospital setting. The effects of sneezing on the airborne dispersal of S. aureus and other bacteria were assessed in 11 healthy nasal S. aureus carriers with experimentally induced rhinovirus colds. Airborne dispersal was studied by volumetric air sampling in 2 chamber sessions with and without histamine-induced sneezing. After 2 days of preexposure measurements, volunteers were inoculated with a rhinovirus and monitored for 14 days. Daily quantitative nasal- and skin-culture samples for bacteria and nasal-culture samples for rhinovirus were obtained, cold symptoms were assessed, and volunteer activities were recorded during sessions. All participants developed a cold. Sneezing caused a 4.7-fold increase in the airborne dispersal of S. aureus, a 1.4-fold increase in coagulase-negative staphylococci (CoNS), and a 3.9-fold increase in other bacteria (P Rhinovirus exposure did not change the frequency of sneezing or airborne dispersal. Having respiratory allergies increased the spread of S. aureus by 3.8-fold during sneezing sessions (P effect of dispersing S. aureus.

  13. Threat of drug resistant Staphylococcus aureus to health in Nepal.

    Science.gov (United States)

    Ansari, Shamshul; Nepal, Hari Prasad; Gautam, Rajendra; Rayamajhi, Nabin; Shrestha, Sony; Upadhyay, Goma; Acharya, Anju; Chapagain, Moti Lal

    2014-03-22

    Staphylococcus aureus is the most commonly isolated organism from the different clinical samples in hospital. The emergence and dissemination of methicillin resistant Staphylococcus aureus (MRSA) and growing resistance to non-beta-lactam antibiotics is making treatment of infections due to this organism increasingly difficult. This study was conducted to determine the frequency of Staphylococcus aureus isolated from different clinical samples, rates of MRSA and full antibiotic susceptibility profiles. Clinical samples were cultured and Staphylococcus aureus was identified using standard microbiological methods recommended by the American Society for Microbiology (ASM). Methicillin resistance was confirmed using cefoxitin and oxacillin disks. Inducible clindamycin resistance was identified using D-zone test. From the processed samples, 306 isolates of Staphylococcus aureus were recovered. All the isolates were susceptible to vancomycin and teicoplanin. Methicillin resistance was observed in 43.1% of isolates while inducible clindamycin resistance in 12.4% of the isolates. The results of our study reveals that rates of resistance to commonly prescribed antibiotics in Staphylococcus aureus clinical isolates is high. In particular, rate of methicillin resistance is alarming, prompting concern on the rational use of antibiotics and vigilant laboratory-based surveillance of resistance rates in Nepal.

  14. Methicillin-resistant Staphylococcus aureus adaptation to human keratinocytes.

    Science.gov (United States)

    Soong, Grace; Paulino, Franklin; Wachtel, Sarah; Parker, Dane; Wickersham, Matthew; Zhang, Dongni; Brown, Armand; Lauren, Christine; Dowd, Margaret; West, Emily; Horst, Basil; Planet, Paul; Prince, Alice

    2015-04-21

    Skin is the most common site of Staphylococcus aureus infection. While most of these infections are self-limited, recurrent infections are common. Keratinocytes and recruited immune cells participate in skin defense against infection. We postulated that S. aureus is able to adapt to the milieu within human keratinocytes to avoid keratinocyte-mediated clearance. From a collection of S. aureus isolated from chronically infected patients with atopic dermatitis, we noted 22% had an agr mutant-like phenotype. Using several models of human skin infection, we demonstrate that toxin-deficient, agr mutants of methicillin-resistant S. aureus (MRSA) USA300 are able to persist within keratinocytes by stimulating autophagy and evading caspase-1 and inflammasome activation. MRSA infection induced keratinocyte autophagy, as evidenced by galectin-8 and LC3 accumulation. Autophagy promoted the degradation of inflammasome components and facilitated staphylococcal survival. The recovery of more than 58% agr or RNAIII mutants (P Soong et al.

  15. Proteinograma e teores de cobre, ferro e zinco no soro sanguíneo de ovelhas da raça Santa Inês com mastite experimental por Staphylococcus aureus Proteinogram and serum concentrations of copper, iron and zinc in Santa Inês ewes with Staphylococcus aureus experimentally induced mastitis

    Directory of Open Access Journals (Sweden)

    Nivaldo de Azevêdo Costa

    2010-05-01

    ório em razão de sua alta correlação com as proteínas especificas. As alterações nas concentrações séricas de Cu, Fe e Zn sugerem a ação de mediadores inflamatórios, estimulados por S. aureus.The aim of the present study was to evaluate the effect of Staphylococcus aureus experimentally induced mastitis on proteinogram and serum concentrations of cupper, iron and zinc levels of Santa Ines primiparous ewes . The right mammary gland of ten healthy ewes was inoculated with 1,0x10(4 UFC/mL of S. aureus. Clinical examination and determination of serum concentrations of proteins by electrophoresis in polyacrylamide gel (SDS-PAGE, cupper, iron and zinc, as well plasma level of fibrinogen were measured before the inoculation (control and 12h, 24h, 36h, 48h, 60h, 72h, 84h, 96h, 108h, 120h, 132h, 168h, 180h, 288h and 336h after bacteria inoculation. All animals experimentally infected presented clinical mastitis and subsequent loss of mammary gland function. The electrophoretogram allowed the identification of 23 proteins with molecular weights (MW ranged from 26.000 to 185.000 daltons (Da including acute-phase proteins, IgG and IgA. A significant increase (P<0,05 in haptoglobin, ceruloplasmin, IgG and IgA concentrations was observed. Antitrypsin and acid glicoprotein concentrations did not alter. The levels of iron and zinc decreased and the cupper concentration increased . A positive correlation between plasma fibrinogen and serum ceruloplasmin (r=0.74, haptoglobin (r=0.62 and IgA (r=0.62 was also identified. Results showed the importance of ceruloplasmin and haptoglobin as acute-phase proteins in ewes with intramammary infections and confirms fibrinogen as an inflammatory marker because its high correlation with specific proteins. The alterations in the serum levels of Cu, Fe and Zn suggest the action of inflammatory mediators triggered by S. aureus.

  16. Cross-Talk between Staphylococcus aureus and Other Staphylococcal Species via the agr Quorum Sensing System

    DEFF Research Database (Denmark)

    Canovas de la Nuez, Jaime; Baldry, Mara; Bojer, Martin S

    2016-01-01

    Staphylococci are associated with both humans and animals. While most are non-pathogenic colonizers, Staphylococcus aureus is an opportunistic pathogen capable of causing severe infections. S. aureus virulence is controlled by the agr quorum sensing system responding to secreted auto-inducing pep...

  17. Proof of Principle for a Real-Time Pathogen Isolation Media Diagnostic: The Use of Laser-Induced Breakdown Spectroscopy to Discriminate Bacterial Pathogens and Antimicrobial-Resistant Staphylococcus aureus Strains Grown on Blood Agar

    Directory of Open Access Journals (Sweden)

    Rosalie A. Multari

    2013-01-01

    Full Text Available Laser-Induced Breakdown Spectroscopy (LIBS is a rapid, in situ, diagnostic technique in which light emissions from a laser plasma formed on the sample are used for analysis allowing automated analysis results to be available in seconds to minutes. This speed of analysis coupled with little or no sample preparation makes LIBS an attractive detection tool. In this study, it is demonstrated that LIBS can be utilized to discriminate both the bacterial species and strains of bacterial colonies grown on blood agar. A discrimination algorithm was created based on multivariate regression analysis of spectral data. The algorithm was deployed on a simulated LIBS instrument system to demonstrate discrimination capability using 6 species. Genetically altered Staphylococcus aureus strains grown on BA, including isogenic sets that differed only by the acquisition of mutations that increase fusidic acid or vancomycin resistance, were also discriminated. The algorithm successfully identified all thirteen cultures used in this study in a time period of 2 minutes. This work provides proof of principle for a LIBS instrumentation system that could be developed for the rapid discrimination of bacterial species and strains demonstrating relatively minor genomic alterations using data collected directly from pathogen isolation media.

  18. Atividade funcional neutrofílica em cabras com mastite induzida experimentalmente por Staphylococcus aureus e suplementadas com vitamina E (acetato DL-a-tocoferol Neutrophilic function activity in goats with mastitis experimentally induced by Staphylococcus aureus and supplemented with vitamin E (acetate DL-a-tocopherol

    Directory of Open Access Journals (Sweden)

    S.T.A. Lopes

    2003-10-01

    Full Text Available Avaliou-se a função neutrofílica em cabras com mastite por Staphylococcus aureus, induzida experimentalmente, suplementadas com vitamina E (acetato DL-a-tocoferol. Foram utilizadas 14 cabras gestantes da raça Saanen, com idades entre 8 e 12 meses e com cultura bacteriológica do leite negativa. Sete cabras receberam 2000UI de vitamina E, via intramuscular, no dia do parto e no sétimo dia pós-parto. As outras sete não foram medicadas. No 10º dia pós-parto, os dois grupos foram inoculados com 300 unidades formadoras de colônias de Staphylococcus aureus, cepa ATCC 25923, diluídas em 10ml de solução fisiológica, na glândula mamária esquerda. A função de neutrófilos sangüíneos foi medida pelo teste nitroazul tetrazólio (NBT, antes da inoculação, no momento da infecção e 12, 24, 48 e 72 horas pós-infecção, quando foi instituído o tratamento intramamário com antimicrobiano, por três dias consecutivos. A colheita final de sangue foi realizada 48 horas após a última aplicação do medicamento. Amostras de sangue para determinação da vitamina E foram colhidas no dia do parto, no momento da infecção, 48 horas pós-infecção e 48 horas pós-tratamento e analisadas por cromatografia líquida de alta performance. Na prova não estimulada do NBT não foram verificadas diferenças entre grupos e entre momentos. Na prova estimulada do NBT (NBT-E houve diferença entre tratamentos às 12 e 72 horas pós-infecção, com valores mais elevados de NBT-E nos animais sem suplementação. Conclui-se que a suplementação com vitamina E reduz o percentual de neutrófilos NBT-E positivos.Neutrophil function in experimentally induced mastitis in goats, inoculated with Staphylococcus aureus supplemented and not supplemented with vitamin E (acetate DL-a-tocopherol was evaluated. Fourteen pregnant Saanen goats, between 8 and 12 months of age all negative in bacteriological milk cultures, were used. Seven goats were treated with 2,000 IU

  19. Utility of (11)C-methionine and (11)C-donepezil for imaging of Staphylococcus aureus induced osteomyelitis in a juvenile porcine model

    DEFF Research Database (Denmark)

    Afzelius, Pia; Alstrup, Aage Ko; Schønheyder, Henrik C

    2016-01-01

    -FDG) PET to improve detection of osteomyelitis. The tracers' diagnostic utility where tested in a juvenile porcine hematogenously induced osteomyelitis model comparable to osteomyelitis in children. Five 8-9 weeks old female domestic pigs were scanned seven days after intra-arterial inoculation...

  20. Cross-Talk between Staphylococcus aureus and Other Staphylococcal Species via the agr Quorum Sensing System

    Directory of Open Access Journals (Sweden)

    Jaime Canovas

    2016-11-01

    Full Text Available Staphylococci are associated with both humans and animals. While most are non-pathogenic colonizers, Staphylococcus aureus is an opportunistic pathogen capable of causing severe infections. S. aureus virulence is controlled by the agr quorum sensing system responding to secreted auto-inducing peptides (AIPs sensed by AgrC, a two component histidine kinase. agr loci are found also in other staphylococcal species and for Staphylococcus epidermidis, the encoded AIP represses expression of agr regulated virulence genes in S. aureus. In this study we aimed to better understand the interaction between staphylococci and S. aureus, and show that this interaction may eventually lead to the identification of new anti-virulence candidates to target S. aureus infections. Here we show that culture supernatants of 37 out of 52 staphylococcal isolates representing 17 different species inhibit S. aureus agr. The dog pathogen, Staphylococcus schleiferi, expressed the most potent inhibitory activity and was active against all four agr classes found in S. aureus. By employing a S. aureus strain encoding a constitutively active AIP receptor we show that the activity is mediated via agr. Subsequent cloning and heterologous expression of the S. schleiferi AIP in S. aureus demonstrated that this molecule was likely responsible for the inhibitory activity, and further proof was provided when pure synthetic S. schleiferi AIP was able to completely abolish agr induction of an S. aureus reporter strain. To assess impact on S. aureus virulence, we co-inoculated S. aureus and S. schleiferi in vivo in the Galleria mellonella wax moth larva, and found that expression of key S. aureus virulence factors was abrogated. Our data show that the S. aureus agr locus is highly responsive to other staphylococcal species suggesting that agr is an inter-species communication system. Based on these results we speculate that interactions between S. aureus and other colonizing staphylococci

  1. Cross-Talk between Staphylococcus aureus and Other Staphylococcal Species via the agr Quorum Sensing System

    Science.gov (United States)

    Canovas, Jaime; Baldry, Mara; Bojer, Martin S.; Andersen, Paal S.; Gless, Bengt H.; Grzeskowiak, Piotr K.; Stegger, Marc; Damborg, Peter; Olsen, Christian A.; Ingmer, Hanne

    2016-01-01

    Staphylococci are associated with both humans and animals. While most are non-pathogenic colonizers, Staphylococcus aureus is an opportunistic pathogen capable of causing severe infections. S. aureus virulence is controlled by the agr quorum sensing system responding to secreted auto-inducing peptides (AIPs) sensed by AgrC, a two component histidine kinase. agr loci are found also in other staphylococcal species and for Staphylococcus epidermidis, the encoded AIP represses expression of agr regulated virulence genes in S. aureus. In this study we aimed to better understand the interaction between staphylococci and S. aureus, and show that this interaction may eventually lead to the identification of new anti-virulence candidates to target S. aureus infections. Here we show that culture supernatants of 37 out of 52 staphylococcal isolates representing 17 different species inhibit S. aureus agr. The dog pathogen, Staphylococcus schleiferi, expressed the most potent inhibitory activity and was active against all four agr classes found in S. aureus. By employing a S. aureus strain encoding a constitutively active AIP receptor we show that the activity is mediated via agr. Subsequent cloning and heterologous expression of the S. schleiferi AIP in S. aureus demonstrated that this molecule was likely responsible for the inhibitory activity, and further proof was provided when pure synthetic S. schleiferi AIP was able to completely abolish agr induction of an S. aureus reporter strain. To assess impact on S. aureus virulence, we co-inoculated S. aureus and S. schleiferi in vivo in the Galleria mellonella wax moth larva, and found that expression of key S. aureus virulence factors was abrogated. Our data show that the S. aureus agr locus is highly responsive to other staphylococcal species suggesting that agr is an inter-species communication system. Based on these results we speculate that interactions between S. aureus and other colonizing staphylococci will significantly

  2. Inhibition of Staphylococcus aureus Invasion into Bovine Mammary Epithelial Cells by Contact with Live Lactobacillus casei

    Science.gov (United States)

    Bouchard, Damien S.; Rault, Lucie; Berkova, Nadia; Le Loir, Yves

    2013-01-01

    Staphylococcus aureus is a major pathogen that is responsible for mastitis in dairy herds. S. aureus mastitis is difficult to treat and prone to recurrence despite antibiotic treatment. The ability of S. aureus to invade bovine mammary epithelial cells (bMEC) is evoked to explain this chronicity. One sustainable alternative to treat or prevent mastitis is the use of lactic acid bacteria (LAB) as mammary probiotics. In this study, we tested the ability of Lactobacillus casei strains to prevent invasion of bMEC by two S. aureus bovine strains, RF122 and Newbould305, which reproducibly induce acute and moderate mastitis, respectively. L. casei strains affected adhesion and/or internalization of S. aureus in a strain-dependent manner. Interestingly, L. casei CIRM-BIA 667 reduced S. aureus Newbould305 and RF122 internalization by 60 to 80%, and this inhibition was confirmed for two other L. casei strains, including one isolated from bovine teat canal. The protective effect occurred without affecting bMEC morphology and viability. Once internalized, the fate of S. aureus was not affected by L. casei. It should be noted that L. casei was internalized at a low rate but survived in bMEC cells with a better efficiency than that of S. aureus RF122. Inhibition of S. aureus adhesion was maintained with heat-killed L. casei, whereas contact between live L. casei and S. aureus or bMEC was required to prevent S. aureus internalization. This first study of the antagonism of LAB toward S. aureus in a mammary context opens avenues for the development of novel control strategies against this major pathogen. PMID:23183972

  3. Thymol inhibits Staphylococcus aureus internalization into bovine mammary epithelial cells by inhibiting NF-κB activation.

    Science.gov (United States)

    Wei, Zhengkai; Zhou, Ershun; Guo, Changming; Fu, Yunhe; Yu, Yuqiang; Li, Yimeng; Yao, Minjun; Zhang, Naisheng; Yang, Zhengtao

    2014-01-01

    Bovine mastitis is one of the most costly and prevalent diseases in the dairy industry and is characterised by inflammatory and infectious processes. Staphylococcus aureus (S. aureus), a Gram-positive organism, is a frequent cause of subclinical, chronic mastitis. Thymol, a monocyclic monoterpene compound isolated from Thymus vulgaris, has been reported to have antibacterial properties. However, the effect of thymol on S. aureus internalization into bovine mammary epithelial cells (bMEC) has not been investigated. In this study, we evaluated the effect of thymol on S. aureus internalization into bMEC, the expression of tracheal antimicrobial peptide (TAP) and β-defensin (BNBD5), and the inhibition of NF-κB activation in bMEC infected with S. aureus. Our results showed that thymol (16-64 μg/ml) could reduce the internalization of S. aureus into bMEC and down-regulate the mRNA expression of TAP and BNBD5 in bMEC infected with S. aureus. In addition, thymol was found to inhibit S. aureus-induced nitric oxide (NO) production in bMEC and suppress S. aureus-induced NF-κB activation in a dose-dependent manner. In conclusion, these results indicated that thymol inhibits S. aureus internalization into bMEC by inhibiting NF-κB activation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Staphylococcus aureus paplitimas hospitalizavimo laikotarpiu

    OpenAIRE

    Maželienė, Žaneta; Kaukėnienė, Renata; Antuševas, Aleksandras; Pavilonis, Alvydas

    2008-01-01

    Objective. To determine the prevalence of Staphylococcus aureus strains among hospitalized patients at the beginning of their hospitalization and during their treatment and the resistance of strains to antibiotics, and to evaluate epidemiologic characteristics of these strains. Patients and methods. Sixty-one patients treated at the Department of Cardiac, Thoracic and Vascular Surgery were examined. Identification of Staphylococcus aureus strains was performed using plasmacoagulase and DNase ...

  5. A secreted bacterial protease tailors the Staphylococcus aureus virulence repertoire to modulate bone remodeling during osteomyelitis

    Science.gov (United States)

    Cassat, James E.; Hammer, Neal D.; Campbell, J. Preston; Benson, Meredith A.; Perrien, Daniel S.; Mrak, Lara N.; Smeltzer, Mark S.; Torres, Victor J.; Skaar, Eric P.

    2013-01-01

    Summary Osteomyelitis is a common manifestation of invasive Staphylococcus aureus infection. Pathogen-induced bone destruction limits antimicrobial penetration to the infectious focus and compromises treatment of osteomyelitis. To investigate mechanisms of S. aureus-induced bone destruction, we developed a murine model of osteomyelitis. Micro-computed tomography of infected femurs revealed that S. aureus triggers profound alterations in bone turnover. The bacterial regulatory locus sae was found to be critical for osteomyelitis pathogenesis, as Sae-regulated factors promote pathologic bone remodeling and intraosseous bacterial survival. Exoproteome analyses revealed the Sae-regulated protease aureolysin as a major determinant of the S. aureus secretome and identified the phenol soluble modulins as aureolysin-degraded, osteolytic peptides that trigger osteoblast cell death and bone destruction. These studies establish a murine model for pathogen-induced bone remodeling, define Sae as critical for osteomyelitis pathogenesis, and identify protease-dependent exoproteome remodeling as a major determinant of the staphylococcal virulence repertoire. PMID:23768499

  6. Increased Susceptibility of Humanized NSG Mice to Panton-Valentine Leukocidin and Staphylococcus aureus Skin Infection.

    Directory of Open Access Journals (Sweden)

    Ching Wen Tseng

    Full Text Available Staphylococcus aureus is a leading cause of skin and soft-tissue infections worldwide. Mice are the most commonly used animals for modeling human staphylococcal infections. However a supra-physiologic S. aureus inoculum is required to establish gross murine skin pathology. Moreover, many staphylococcal factors, including Panton-Valentine leukocidin (PVL elaborated by community-associated methicillin-resistant S. aureus (CA-MRSA, exhibit selective human tropism and cannot be adequately studied in mice. To overcome these deficiencies, we investigated S. aureus infection in non-obese diabetic (NOD/severe combined immune deficiency (SCID/IL2rγnull (NSG mice engrafted with human CD34+ umbilical cord blood cells. These "humanized" NSG mice require one to two log lower inoculum to induce consistent skin lesions compared with control mice, and exhibit larger cutaneous lesions upon infection with PVL+ versus isogenic PVL- S. aureus. Neutrophils appear important for PVL pathology as adoptive transfer of human neutrophils alone to NSG mice was sufficient to induce dermonecrosis following challenge with PVL+ S. aureus but not PVL- S. aureus. PMX53, a human C5aR inhibitor, blocked PVL-induced cellular cytotoxicity in vitro and reduced the size difference of lesions induced by the PVL+ and PVL- S. aureus, but PMX53 also reduced recruitment of neutrophils and exacerbated the infection. Overall, our findings establish humanized mice as an important translational tool for the study of S. aureus infection and provide strong evidence that PVL is a human virulence factor.

  7. Killing of Staphylococcus aureus via Magnetic Hyperthermia Mediated by Magnetotactic Bacteria.

    Science.gov (United States)

    Chen, Changyou; Chen, Linjie; Yi, Yong; Chen, Chuanfang; Wu, Long-Fei; Song, Tao

    2016-02-12

    Staphylococcus aureus is a common hospital and household pathogen. Given the emergence of antibiotic-resistant derivatives of this pathogen resulting from the use of antibiotics as general treatment, development of alternative therapeutic strategies is urgently needed. Here, we assess the feasibility of killing S. aureus cells in vitro and in vivo through magnetic hyperthermia mediated by magnetotactic bacteria that possess magnetic nanocrystals and demonstrate magnetically steered swimming. The S. aureus suspension was added to magnetotactic MO-1 bacteria either directly or after coating with anti-MO-1 polyclonal antibodies. The suspensions were then subjected to an alternating magnetic field (AMF) for 1 h. S. aureus viability was subsequently assessed through conventional plate counting and flow cytometry. We found that approximately 30% of the S. aureus cells mixed with uncoated MO-1 cells were killed after AMF treatment. Moreover, attachment between the magnetotactic bacteria and S. aureus increased the killing efficiency of hyperthermia to more than 50%. Using mouse models, we demonstrated that magnetic hyperthermia mediated by antibody-coated magnetotactic MO-1 bacteria significantly improved wound healing. These results collectively demonstrated the effective eradication of S. aureus both in vitro and in vivo, indicating the potential of magnetotactic bacterium-mediated magnetic hyperthermia as a treatment for S. aureus-induced skin or wound infections. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  8. Subinhibitory concentrations of punicalagin reduces expression of virulence-related exoproteins by Staphylococcus aureus.

    Science.gov (United States)

    Mun, Su-Hyun; Kong, Ryong; Seo, Yun-Soo; Zhou, Tian; Kang, Ok-Hwa; Shin, Dong-Won; Kwon, Dong-Yeul

    2016-11-01

    Staphylococcus aureus produces a number of virulence factors. The major virulence factors exhibited by S aureus include various antigens, enzymes, cytotoxins and exotoxins (e.g. hemolysins, enterotoxins and toxic shock syndrome toxin). In this report, we show the influence of punicalagin on the secretion of exoprotein from S aureus by western blotting, tumor necrosis factor (TNF) release assay and quantitative RT-PCR. When added to S aureus cultures at an OD600 of 0.9, graded subinhibitory concentrations of punicalagin reduced the production of α-toxin, SEA and SEB in methicillin-resistant Staphylococcus aureus in a dose-dependent manner. Consistently, punicalagin reduced TNF-inducing activity by S aureus culture supernatants. Here, the transcriptional level of agr (accessory gene regulator) in S aureus was inhibited by punicalagin, suggesting that the reduced transcription may affect the secretion of exotoxins. These findings suggest that the expression of α-toxin and enterotoxins in S aureus is sensitive to the action of punicalagin, which may be an advantageous candidate in the treatment of toxigenic staphylococcal disease. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Staphylococcus aureus hijacks a skin commensal to intensify its virulence: immunization targeting β-hemolysin and CAMP factor.

    Science.gov (United States)

    Lo, Chih-Wei; Lai, Yiu-Kay; Liu, Yu-Tsueng; Gallo, Richard L; Huang, Chun-Ming

    2011-02-01

    The need for a new anti-Staphylococcus aureus therapy that can effectively cripple bacterial infection, neutralize secretory virulence factors, and lower the risk of creating bacterial resistance is undisputed. Here, we propose what is, to our knowledge, a previously unreported infectious mechanism by which S. aureus may commandeer Propionibacterium acnes, a key member of the human skin microbiome, to spread its invasion and highlight two secretory virulence factors (S. aureus β-hemolysin and P. acnes CAMP (Christie, Atkins, Munch-Peterson) factor) as potential molecular targets for immunotherapy against S. aureus infection. Our data demonstrate that the hemolysis and cytolysis by S. aureus were noticeably augmented when S. aureus was grown with P. acnes. The augmentation was significantly abrogated when the P. acnes CAMP factor was neutralized or β-hemolysin of S. aureus was mutated. In addition, the hemolysis and cytolysis of recombinant β-hemolysin were markedly enhanced by recombinant CAMP factor. Furthermore, P. acnes exacerbated S. aureus-induced skin lesions in vivo. The combination of CAMP factor neutralization and β-hemolysin immunization cooperatively suppressed the skin lesions caused by coinfection of P. acnes and S. aureus. These observations suggest a previously unreported immunotherapy targeting the interaction of S. aureus with a skin commensal.

  10. Metabolic Stress Drives Keratinocyte Defenses against Staphylococcus aureus Infection

    Directory of Open Access Journals (Sweden)

    Matthew Wickersham

    2017-03-01

    Full Text Available Human skin is commonly colonized and infected by Staphylococcus aureus. Exactly how these organisms are sensed by keratinocytes has not been clearly delineated. Using a combination of metabolic and transcriptomic methodologies, we found that S. aureus infection is sensed as a metabolic stress by the hypoxic keratinocytes. This induces HIF1α signaling, which promotes IL-1β production and stimulates aerobic glycolysis to meet the metabolic requirements of infection. We demonstrate that staphylococci capable of glycolysis, including WT and agr mutants, readily induce HIF1α responses. In contrast, Δpyk glycolytic mutants fail to compete with keratinocytes for their metabolic needs. Suppression of glycolysis using 2-DG blocked keratinocyte production of IL-1β in vitro and significantly exacerbated the S. aureus cutaneous infection in a murine model. Our data suggest that S. aureus impose a metabolic stress on keratinocytes that initiates signaling necessary to promote both glycolysis and the proinflammatory response to infection.

  11. Evaluation of a lysostaphin-fusion protein as a dry-cow therapy for Staphylococcus aureus mastitis in dairy cattle

    Science.gov (United States)

    This study evaluated the efficacy of a lysostaphin-fusion protein (Lyso-PTD) as a dry-cow therapy for the treatment of experimentally-induced chronic, subclinical Staphylococcus aureus mastitis. Twenty-two Holstein dairy cows were experimentally infected with Staph. aureus in a single pair of diago...

  12. Involvement of Mitogen-Activated Protein Kinase Pathways in Staphylococcus aureus Invasion of Normal Osteoblasts

    Science.gov (United States)

    Ellington, John K.; Elhofy, Adam; Bost, Kenneth L.; Hudson, Michael C.

    2001-01-01

    Staphylococcus aureus invades osteoblasts and can persist in the intracellular environment. The present study examined the role of osteoblast mitogen-activated protein kinase (MAPK) pathways in bacterial invasion. S. aureus infection of normal human and mouse osteoblasts resulted in an increase in the phosphorylation of the extracellular signal-regulated protein kinases (ERK 1 and 2). This stimulation of ERK 1 and 2 correlated with the time course of S. aureus invasion, and bacterial adherence induced the MAPK pathway. ERK 1 and 2 phosphorylation was time and dose dependent and required active S. aureus gene expression for maximal induction. The nonpathogenic Staphylococcus carnosus was also able to induce ERK 1 and 2 phosphorylation, albeit at lower levels than S. aureus. Phosphorylation of the stress-activated protein kinases was increased in both infected human and mouse osteoblasts; however, the p38 MAPK pathway was not activated in response to S. aureus. Finally, the transcription factor c-Jun, but not Elk-1 or ATF-2, was phosphorylated in response to S. aureus infection. PMID:11500391

  13. [Protein toxins of Staphylococcus aureus].

    Science.gov (United States)

    Shamsutdinov, A F; Tiurin, Iu A

    2014-01-01

    Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented.

  14. Staphylococcus aureus Nasal Carriage among Surgical personnel ...

    African Journals Online (AJOL)

    Introduction: Staphylococcus aureus (S. aureus) is one of the most common causes of both community and hospital acquired bacterial infection. There is strong correlation between S aureus nasal carriage and disease progress. Nasal carriage is high among health care workers. Inappropriate usage of antibiotic may

  15. Nasal Carriage of Staphylococcus aureus and Antibiotic ...

    African Journals Online (AJOL)

    Nasal carriage of Staphylococcus aureus has been demonstrated to be a major risk factor for invasive S. aureus infections in various population including children. The extent of S. aureus carriage in Sierra Leonean children is largely unknown. To determine the prevalence and pattern of antibiotic susceptibility of nasal S.

  16. Staphylococcus aureus transmission : clinical and molecular aspects

    NARCIS (Netherlands)

    Bloemendaal, A.L.A.

    2010-01-01

    Staphylococcus aureus is a major pathogen in nosocomial infections. Up to 30% of UCI related infections are caused by S. aureus. In this thesis we explore both clinical and molecular aspects of patient-to-patient transmission of S. aureus. We performed a European ICU study exploring infection

  17. Vancomycin Sensitivity of Staphylococcus aureus isolates from ...

    African Journals Online (AJOL)

    Methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA), resistant to all antibiotics including Vancomycin, has been reported in Japan, USA, Canada and Brazil. Hence, the main objective of this study was to evaluate the possible presence of Vancomycin resistant or intermediate S.aureus in Karachi. A total of 850 ...

  18. Stress Responses in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Frees, Dorte; Ingmer, Hanne

    2016-01-01

    Staphylococcus aures are prominent members of the normal flora of humans and animals, but are also a major cause of mild and severe infections. To persist and disseminate in the human host, and to survive in environmental settings, such as hospitals, S. aureus have developed a plethora of cellular...

  19. Dysbiosis and Staphylococcus aureus Colonization Drives Inflammation in Atopic Dermatitis.

    Science.gov (United States)

    Kobayashi, Tetsuro; Glatz, Martin; Horiuchi, Keisuke; Kawasaki, Hiroshi; Akiyama, Haruhiko; Kaplan, Daniel H; Kong, Heidi H; Amagai, Masayuki; Nagao, Keisuke

    2015-04-21

    Staphylococcus aureus skin colonization is universal in atopic dermatitis and common in cancer patients treated with epidermal growth factor receptor inhibitors. However, the causal relationship of dysbiosis and eczema has yet to be clarified. Herein, we demonstrate that Adam17(fl/fl)Sox9-(Cre) mice, generated to model ADAM17-deficiency in human, developed eczematous dermatitis with naturally occurring dysbiosis, similar to that observed in atopic dermatitis. Corynebacterium mastitidis, S. aureus, and Corynebacterium bovis sequentially emerged during the onset of eczematous dermatitis, and antibiotics specific for these bacterial species almost completely reversed dysbiosis and eliminated skin inflammation. Whereas S. aureus prominently drove eczema formation, C. bovis induced robust T helper 2 cell responses. Langerhans cells were required for eliciting immune responses against S. aureus inoculation. These results characterize differential contributions of dysbiotic flora during eczema formation, and highlight the microbiota-host immunity axis as a possible target for future therapeutics in eczematous dermatitis. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Expression of virulence factors by Staphylococcus aureus grown in serum.

    Science.gov (United States)

    Oogai, Yuichi; Matsuo, Miki; Hashimoto, Masahito; Kato, Fuminori; Sugai, Motoyuki; Komatsuzawa, Hitoshi

    2011-11-01

    Staphylococcus aureus produces many virulence factors, including toxins, immune-modulatory factors, and exoenzymes. Previous studies involving the analysis of virulence expression were mainly performed by in vitro experiments using bacterial medium. However, when S. aureus infects a host, the bacterial growth conditions are quite different from those in a medium, which may be related to the different expression of virulence factors in the host. In this study, we investigated the expression of virulence factors in S. aureus grown in calf serum. The expression of many virulence factors, including hemolysins, enterotoxins, proteases, and iron acquisition factors, was significantly increased compared with that in bacterial medium. In addition, the expression of RNA III, a global regulon for virulence expression, was significantly increased. This effect was partially restored by the addition of 300 μM FeCl₃ into serum, suggesting that iron depletion is associated with the increased expression of virulence factors in serum. In chemically defined medium without iron, a similar effect was observed. In a mutant with agr inactivated grown in serum, the expression of RNA III, psm, and sec4 was not increased, while other factors were still induced in the mutant, suggesting that another regulatory factor(s) is involved. In addition, we found that serum albumin is a major factor for the capture of free iron to prevent the supply of iron to bacteria grown in serum. These results indicate that S. aureus expresses virulence factors in adaptation to the host environment.

  1. Molecular Basis of Virulence in Staphylococcus aureus Mastitis

    Science.gov (United States)

    Le Maréchal, Caroline; Seyffert, Nubia; Jardin, Julien; Hernandez, David; Jan, Gwenaël; Rault, Lucie; Azevedo, Vasco; François, Patrice; Schrenzel, Jacques; van de Guchte, Maarten; Even, Sergine; Berkova, Nadia; Thiéry, Richard; Fitzgerald, J. Ross

    2011-01-01

    Background S. aureus is one of the main pathogens involved in ruminant mastitis worldwide. The severity of staphylococcal infection is highly variable, ranging from subclinical to gangrenous mastitis. This work represents an in-depth characterization of S. aureus mastitis isolates to identify bacterial factors involved in severity of mastitis infection. Methodology/Principal Findings We employed genomic, transcriptomic and proteomic approaches to comprehensively compare two clonally related S. aureus strains that reproducibly induce severe (strain O11) and milder (strain O46) mastitis in ewes. Variation in the content of mobile genetic elements, iron acquisition and metabolism, transcriptional regulation and exoprotein production was observed. In particular, O11 produced relatively high levels of exoproteins, including toxins and proteases known to be important in virulence. A characteristic we observed in other S. aureus strains isolated from clinical mastitis cases. Conclusions/Significance Our data are consistent with a dose-dependant role of some staphylococcal factors in the hypervirulence of strains isolated from severe mastitis. Mobile genetic elements, transcriptional regulators, exoproteins and iron acquisition pathways constitute good targets for further research to define the underlying mechanisms of mastitis severity. PMID:22096559

  2. Distinct pathogenesis and host responses during infection of C. elegans by P. aeruginosa and S. aureus.

    Directory of Open Access Journals (Sweden)

    Javier E Irazoqui

    2010-07-01

    Full Text Available The genetically tractable model host Caenorhabditis elegans provides a valuable tool to dissect host-microbe interactions in vivo. Pseudomonas aeruginosa and Staphylococcus aureus utilize virulence factors involved in human disease to infect and kill C. elegans. Despite much progress, virtually nothing is known regarding the cytopathology of infection and the proximate causes of nematode death. Using light and electron microscopy, we found that P. aeruginosa infection entails intestinal distention, accumulation of an unidentified extracellular matrix and P. aeruginosa-synthesized outer membrane vesicles in the gut lumen and on the apical surface of intestinal cells, the appearance of abnormal autophagosomes inside intestinal cells, and P. aeruginosa intracellular invasion of C. elegans. Importantly, heat-killed P. aeruginosa fails to elicit a significant host response, suggesting that the C. elegans response to P. aeruginosa is activated either by heat-labile signals or pathogen-induced damage. In contrast, S. aureus infection causes enterocyte effacement, intestinal epithelium destruction, and complete degradation of internal organs. S. aureus activates a strong transcriptional response in C. elegans intestinal epithelial cells, which aids host survival during infection and shares elements with human innate responses. The C. elegans genes induced in response to S. aureus are mostly distinct from those induced by P. aeruginosa. In contrast to P. aeruginosa, heat-killed S. aureus activates a similar response as live S. aureus, which appears to be independent of the single C. elegans Toll-Like Receptor (TLR protein. These data suggest that the host response to S. aureus is possibly mediated by pathogen-associated molecular patterns (PAMPs. Because our data suggest that neither the P. aeruginosa nor the S. aureus-triggered response requires canonical TLR signaling, they imply the existence of unidentified mechanisms for pathogen detection in C

  3. Distinct pathogenesis and host responses during infection of C. elegans by P. aeruginosa and S. aureus.

    Science.gov (United States)

    Irazoqui, Javier E; Troemel, Emily R; Feinbaum, Rhonda L; Luhachack, Lyly G; Cezairliyan, Brent O; Ausubel, Frederick M

    2010-07-01

    The genetically tractable model host Caenorhabditis elegans provides a valuable tool to dissect host-microbe interactions in vivo. Pseudomonas aeruginosa and Staphylococcus aureus utilize virulence factors involved in human disease to infect and kill C. elegans. Despite much progress, virtually nothing is known regarding the cytopathology of infection and the proximate causes of nematode death. Using light and electron microscopy, we found that P. aeruginosa infection entails intestinal distention, accumulation of an unidentified extracellular matrix and P. aeruginosa-synthesized outer membrane vesicles in the gut lumen and on the apical surface of intestinal cells, the appearance of abnormal autophagosomes inside intestinal cells, and P. aeruginosa intracellular invasion of C. elegans. Importantly, heat-killed P. aeruginosa fails to elicit a significant host response, suggesting that the C. elegans response to P. aeruginosa is activated either by heat-labile signals or pathogen-induced damage. In contrast, S. aureus infection causes enterocyte effacement, intestinal epithelium destruction, and complete degradation of internal organs. S. aureus activates a strong transcriptional response in C. elegans intestinal epithelial cells, which aids host survival during infection and shares elements with human innate responses. The C. elegans genes induced in response to S. aureus are mostly distinct from those induced by P. aeruginosa. In contrast to P. aeruginosa, heat-killed S. aureus activates a similar response as live S. aureus, which appears to be independent of the single C. elegans Toll-Like Receptor (TLR) protein. These data suggest that the host response to S. aureus is possibly mediated by pathogen-associated molecular patterns (PAMPs). Because our data suggest that neither the P. aeruginosa nor the S. aureus-triggered response requires canonical TLR signaling, they imply the existence of unidentified mechanisms for pathogen detection in C. elegans, with

  4. Type I signal peptidase and protein secretion in Staphylococcus aureus.

    Science.gov (United States)

    Schallenberger, Mark A; Niessen, Sherry; Shao, Changxia; Fowler, Bruce J; Romesberg, Floyd E

    2012-05-01

    Staphylococcus aureus is an important human pathogen whose virulence relies on the secretion of many different proteins. In general, the secretion of most proteins in S. aureus, as well as other bacteria, is dependent on the type I signal peptidase (SPase)-mediated cleavage of the N-terminal signal peptide that targets a protein to the general secretory pathway. The arylomycins are a class of natural product antibiotics that inhibit SPase, suggesting that they may be useful chemical biology tools for characterizing the secretome. While wild-type S. aureus (NCTC 8325) is naturally resistant to the arylomycins, sensitivity is conferred via a point mutation in its SPase. Here, we use a synthetic arylomycin along with a sensitized strain of S. aureus and multidimensional protein identification technology (MudPIT) mass spectrometry to identify 46 proteins whose extracellular accumulation requires SPase activity. Forty-four possess identifiable Sec-type signal peptides and thus are likely canonically secreted proteins, while four also appear to possess cell wall retention signals. We also identified the soluble C-terminal domains of two transmembrane proteins, lipoteichoic acid synthase, LtaS, and O-acyteltransferase, OatA, both of which appear to have noncanonical, internal SPase cleavage sites. Lastly, we identified three proteins, HtrA, PrsA, and SAOUHSC_01761, whose secretion is induced by arylomycin treatment. In addition to elucidating fundamental aspects of the physiology and pathology of S. aureus, the data suggest that an arylomycin-based therapeutic would reduce virulence while simultaneously eradicating an infection.

  5. Acacetin Protects Mice from Staphylococcus aureus Bloodstream Infection by Inhibiting the Activity of Sortase A

    Directory of Open Access Journals (Sweden)

    Chongwei Bi

    2016-09-01

    Full Text Available Staphylococcus aureus (S. aureus is a major cause of infection in hospitals and communities. Widespread dissemination of multi-drug resistant S. aureus is a serious threat to the health of humans and animals. An anti-virulence strategy has been widely considered as an alternative therapeutic approach. Inhibitors of virulence factors are able to treat S. aureus infections without influencing the growth or viability of bacteria and rarely lead to bacterial resistance. Sortase A (SrtA is a membrane-associated cysteine transpeptidase that catalyzes up to 25 surface proteins that covalently bind to cell wall peptidoglycans. In S. aureus, most of these surface proteins have been identified as important virulence factors that are vital in bacterial pathogenesis. In the present study, we show that acacetin, a natural flavonoid compound, inhibits the activity of SrtA in S. aureus (IC50 = 36.46 ± 4.69 μg/mL, 128 μM which affects the assembly of protein A (SpA to cell walls and reduces the binding of S. aureus to fibrinogen (Fg. The mechanism of the interaction between acacetin and SrtA were preliminarily discussed using molecular dynamics simulations. The results suggested that acacetin adopted a compact conformation binding at the pocket of the SrtA via residues Arg-139 and Lys-140. By performing an animal infection model, we demonstrated that acacetin was able to protect mice from renal abscess formation induced by S. aureus and significantly increased survival rates. Taken together, these findings suggest that acacetin may be a promising candidate for the development of anti-S. aureus drugs.

  6. Farrerol regulates antimicrobial peptide expression and reduces Staphylococcus aureus internalization into bovine mammary epithelial cells.

    Science.gov (United States)

    Yang, Zhengtao; Fu, Yunhe; Liu, Bo; Zhou, Ershun; Liu, Zhicheng; Song, Xiaojing; Li, Depeng; Zhang, Naisheng

    2013-12-01

    Mastitis, defined as inflammation of the mammary gland, is an infectious disease with a major economic influence on dairy industry. Staphylococcus aureus is a common gram-positive pathogen that frequently causes subclinical, chronic infection of the mammary gland in dairy cows. Farrerol, a traditional Chinese medicine isolated from rhododendron, has been shown to have anti-bacterial activity. However, the effect of farrerol on S. aureus infection in mammary epithelium has not been studied in detail. The aim of this study was to investigate the effect of farrerol on the invasion of bovine mammary epithelial cells (bMEC) by S. aureus. The expression of antimicrobial peptide genes by bMEC were assessed in the presence or absence of S. aureus infection. Our results demonstrated that farrerol (4-16 μg/ml) reduced > 55% the internalization of S. aureus into bMEC. We also found that farrerol was able to down-regulate the mRNA expression of tracheal antimicrobial peptide (TAP) and bovine neutrophil β-defensin 5 (BNBD5) in bMEC infected with S. aureus. The Nitric oxide (NO) production of bMEC after S. aureus stimulation was decreased by farrerol treatment. Furthermore, farrerol treatment suppressed S. aureus-induced NF-κB activation in bMEC. These results demonstrated that farrerol modulated TAP and BNBD5 gene expression in mammary gland, enhances bMEC defense against S. aureus infection and could be useful in protection against bovine mastitis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Piperine Plays an Anti-Inflammatory Role in Staphylococcus aureus Endometritis by Inhibiting Activation of NF-κB and MAPK Pathways in Mice

    Directory of Open Access Journals (Sweden)

    Wen-jun Zhai

    2016-01-01

    Full Text Available Endometritis is commonly caused by pathogenic microorganisms, including Staphylococcus aureus (S. aureus. Piperine, which is a natural medicine, has shown a variety of biological activities. To explore the effect and mechanism of piperine on S. aureus endometritis, a mouse model of S. aureus endometritis was successfully established in the present study. Histopathological changes were observed with H&E staining, cytokines were analyzed by ELISA, mRNA was analyzed by qPCR, and proteins were detected by western blot. The results showed that piperine could significantly alleviate inflammatory injury in S. aureus endometritis. The qPCR and ELISA results showed that piperine effectively reduced the S. aureus-induced overexpression of TNF-α, IL-1β, and IL-6 but increased the expression of IL-10. The S. aureus-induced inflammation was related to TLR-2 and TLR-4 because the results showed that their expression was increased in S. aureus infection but then decreased with piperine treatment. To further confirm that piperine caused an anti-inflammatory response by targeting NF-κB and MAPKs, the expression of I-κB, p65, p38, ERK, and JNK was measured. The phosphorylation of I-κB, p65, p38, ERK, and JNK was inhibited by piperine in a dose-dependent manner. All of the results indicated that piperine may be a potential anti-inflammatory drug both in endometritis and in other S. aureus-induced diseases.

  8. Development and identification of fully human scFv-Fcs against Staphylococcus aureus.

    Science.gov (United States)

    Nian, Siji; Wu, Tong; Ye, Yingchun; Wang, Xu; Xu, Wenfeng; Yuan, Qing

    2016-04-29

    Staphylococcus aureus, a gram-positive pathogen, causes many human infections. Methicillin-resistant S. aureus (MRSA) is the most common drug-resistance bacteria. Nearly all MRSA bacteria are resistant to several drugs. Specific antibodies are the main components of the host's humoral immunity, and play a significant role in the process of the host's resistance to bacterial infection. A single-chain variable fragment (scFv) library was constructed using mRNA from the peripheral blood mononuclear cells of S. aureus infected volunteers. After the scFv library DNA was transformed into Escherichia coli TG1, ~1.7 × 10(7) independent clones with full-length scFv inserts. The scFv library was screened by phage display for three rounds using S. aureus as an antigen. The single clones were chosen at random and the scFvs were expressed for enzyme-linked immunosorbent assay (ELISA) assessment. Approximately 50 % of the clones were positive with good binding activity to S. aureus. To improve the stability of scFvs, scFv-fragment crystallizable regions (-Fcs) were constructed and expressed in E. coli DH5α. The expressed scFv-Fcs were purified and identified by western blot. These antibodies were further characterized and analyzed for bioactivity. The results showed that the expression level and folding of scFv-Fcs induced at 25 °C without isopropyl β-D-1-thiogalactopyranoside (IPTG) were higher than that induced at 32 °C with 1.0 mmol/L IPTG. scFv-Fcs had good bioactivity and could specifically bind with S. aureus. scFv-Fcs against S. aureus were successfully constructed and are good candidates for the development of future adjunctive therapy for severe S. aureus infections.

  9. ENTEROTOXIGENIC STAPHYLOCOCCUS AUREUS IN SHEEP RAW MILK

    OpenAIRE

    G. Giacinti; Amatiste, S.; A. Tammaro; D. Sagrafoli; G. Giangolini; R. Rosati

    2011-01-01

    A total of 366 raw milk samples from 30 sheep farms were examined quantitatively for Staphylococcus aureus. Enterotoxin production by strains of Staphylococcus aureus isolated was investigated. S. aureus was detected in 19 farms (63,3%). The ability to synthetise enterotoxins was found in ten strains (52,6%). Production of staphylococcal enterotoxins C (SEC) was recorded in 6 (60%) and production of SEC together with staphylococcal enterotoxin A (SEA) in 4 (40%) staphylococcal isolates. Raw m...

  10. Immunomodulation and Disease Tolerance to Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Zhigang Li

    2015-11-01

    Full Text Available The Gram-positive bacterium Staphylococcus aureus is one of the most frequent pathogens that causes severe morbidity and mortality throughout the world. S. aureus can infect skin and soft tissues or become invasive leading to diseases such as pneumonia, endocarditis, sepsis or toxic shock syndrome. In contrast, S. aureus is also a common commensal microbe and is often part of the human nasal microbiome without causing any apparent disease. In this review, we explore the immunomodulation and disease tolerance mechanisms that promote commensalism to S. aureus.

  11. S. aureus colonization at ICU admission as a risk factor for developing S. aureus ICU pneumonia

    NARCIS (Netherlands)

    Paling, Fleur P|info:eu-repo/dai/nl/413968669; Wolkewitz, Martin; Bode, Lonneke G M; Klein Klouwenberg, Peter M C|info:eu-repo/dai/nl/33706864X; Ong, David S Y; Depuydt, Pieter; de Bus, Liesbet; Sifakis, Frangiscos; Bonten, Marc J M|info:eu-repo/dai/nl/123144337; Kluijtmans, Jan|info:eu-repo/dai/nl/323262139

    OBJECTIVE: To quantify the incidence of intensive care unit (ICU) acquired pneumonia caused by Staphylococcus aureus (S. aureus) and its association with S. aureus colonization at ICU admission. METHODS: This was a post-hoc analysis of two cohort studies in critically ill patients. The primary

  12. Relationship and susceptibility profile of Staphylococcus aureus infection diabetic foot ulcers with Staphylococcus aureus nasal carriage.

    Science.gov (United States)

    Taha, Aza Bahadeen

    2013-03-01

    Staphylococcus aureus is the main cause of diabetic foot infection with the patient's endogenous flora as the principal source. Nasal carriage of S. aureus has been identified as an important risk factor for the acquisition of diabetic foot infections. The study assessment the associations of S. aureus with methicillin resistant S. aureus were isolation from diabetic foot infection and nasal carriage of the same patients and their antibiotic susceptibility profile. Diagnosis of S. aureus and methicillin resistant S. aureus were carried out by using standard procedures. Antibiotic sensitivity profiles were determent by breakpoint dilution method. Out of 222 S. aureus isolation, 139 (62.61%) were isolated from the diabetic foot and 83 (37.39%) from the nasal carriage. Seventy one (30.87%) of the patients were S. aureus infection diabetic foot with nasal carriage. Among diabetic foot infection and nasal carriage patients, 40.85% of S. aureus were considered as methicillin resistant S. aureus. Rifampicin (96.40%) and Levofloxacin (91.44%) were active against S. aureus. Patients at strong risk for methicillin resistant S. aureus nasal carriage and subsequent diabetic foot infection with high resistance to antibiotics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Michael R Yeaman

    2014-09-01

    Full Text Available Recent perspectives forecast a new paradigm for future 3rd generation vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologues found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that 1 afford protective efficacy; 2 target an epitope from one organism that contributes to protective immunity against another; 3 cross-protect against multiple pathogens occupying a common anatomic or immunologic niche; and/or 4 overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre–clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in preclinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3 where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target

  14. Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus

    Science.gov (United States)

    Yeaman, Michael R.; Filler, Scott G.; Schmidt, Clint S.; Ibrahim, Ashraf S.; Edwards, John E.; Hennessey, John P.

    2014-01-01

    Recent perspectives forecast a new paradigm for future “third generation” vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high-priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologs found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that (1) afford protective efficacy; (2) target an epitope from one organism that contributes to protective immunity against another; (3) cross-protect against multiple pathogens occupying a common anatomic or immunological niche; and/or (4) overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre-clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in pre-clinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3) where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target S

  15. Induction of Staphylococcus aureus-specific IgA and agglutination potency in milk of cows by mucosal immunization.

    Science.gov (United States)

    Tempelmans Plat-Sinnige, Marjan J; Verkaik, Nelianne J; van Wamel, Willem J B; de Groot, Nanda; Acton, Dennis S; van Belkum, Alex

    2009-06-19

    Lactating cows were immunized with inactivated Staphylococcus aureus strains and concentrated culture supernatants. Application of a repeated mucosal immunization scheme resulted in significant levels of S. aureus-specific IgA in milk of dairy cows. Average IgA titers against whole cell S. aureus increased during the first 10 weeks of immunization after which a plateau level was reached and maintained during lactation. Immune whey agglutinated both bovine and human S. aureus strains including methicillin-resistant S. aureus (MRSA) strains and recognized extracted S. aureus proteins on Western blot. ELISAs to quantify milk IgA reactive with a number of S. aureus virulence proteins (e.g. enterotoxins, microbial surface component recognizing adhesive matrix molecules (MSCRAMMs) and immune modulating proteins) and cell wall components, demonstrated the polyclonality of the IgA. Correlations observed between agglutination and specific IgA titers for whey and for purified IgA suggested functionality of the induced antibodies. Milk from immunized cows may provide a way of producing potentially therapeutic polyclonal antibodies against S. aureus colonization and infection.

  16. Evaluation of Two New Chromogenic Media, CHROMagar MRSA and S. aureus ID, for Identifying Staphylococcus aureus and Screening Methicillin-Resistant S. aureus

    OpenAIRE

    Hedin, Göran; Fang, Hong

    2005-01-01

    Thirty-nine methicillin-resistant Staphylococcus aureus (MRSA) isolates with diverse genetic backgrounds and two reference strains were correctly identified as S. aureus on CHROMagar MRSA and S. aureus ID media. Growth inhibition on CHROMagar MRSA was noted. A combination of cefoxitin disk and S. aureus ID was found suitable for rapid MRSA screening.

  17. Relative prevalence of methicilline resistant Staphylococcus aureus ...

    African Journals Online (AJOL)

    In our region, although methicillin resistance increased in S. aureus strains, because of the unavailability and the high cost of alternative antibiotics, gentamycin is still suggested as an alternative for treatment of S. aureus infections. These results however indicate that vancomycin seemed to be the only antimicrobial agent ...

  18. Characterization of Staphylococcus aureus nasal colonization rates ...

    African Journals Online (AJOL)

    Carriers of Staphylococcus aureus have an important role in its dissemination. The colonization rates of S. aureus in anterior nose nares from 210 healthy volunteers (70 from the non-hospital adult personnel in the community, 68 from clinical students and 72 from healthcare workers “HCWs” in 6 hospitals) in the eastern ...

  19. METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA ...

    African Journals Online (AJOL)

    Nosocomial infections caused by methicillin-resistant strains of Staphylococcus aureus often pose therapeutic dilemma to the clinicians because of the multi resistant nature of these strains of Staphylococcus aureus. Outbreaks of both nosocomial and community acquired infections are also frequent and difficult to control.

  20. (allium sativum) on staphylococcus aureus conjunctivites

    African Journals Online (AJOL)

    INTRODUCTION. Bacterial conjunctivitis is common usually self-limiting. The most common causative organisms are staphylococcus epidermis and staphylococcus aureus (S. aureus). Bacterial conjunctivitis is rarely sight threatening. However, accurate diagnosis and prompt treatment at the primary level is important as it ...

  1. Nasal Carriage of Methicillin Resistant Staphylococcus aureus ...

    African Journals Online (AJOL)

    BACKGROUND: Staphylococcus aureus is one of the major causes of community and hospital acquired infections. The emergence of methicillin resistant strains of Staphylococcus aureus in the hospitals and the community is a serious health problem. The aim of this study was to determine the nasal carriage and ...

  2. Antimicrobial resistant coagulase positive Staphylococcus aureus ...

    African Journals Online (AJOL)

    Staphylococcus aureus is an Important agent of food poisoning. In many countries, it is the main bacterial organism responsible for diseases caused by exotoxin production and direct invasion with systemic dissemination. In poultry, S. aureus is associated with many clinical syndromes including tenosynovitis, omphalitis, ...

  3. Immunogenicity of toxins during Staphylococcus aureus infection

    NARCIS (Netherlands)

    N.J. Verkaik (Nelianne); O. Dauwalder (Olivier); K. Antri (Kenza); I. Boubekri (Ilhem); C.P. de Vogel (Corné); C. Badiou (Cédric); M. Bes (Michèle); F. Vandenesch (François); M. Tazir (Mohammed); H. Hooijkaas (Herbert); H.A. Verbrugh (Henri); A.F. van Belkum (Alex); J. Etienne (Jerome); G. Lina (Gérard); N. Ramdani-Bouguessa (Nadjia); W.J.B. van Wamel (Willem)

    2010-01-01

    textabstractAB - BACKGROUND: Toxins are important Staphylococcus aureus virulence factors, but little is known about their immunogenicity during infection. Here, additional insight is generated. METHODS: Serum samples from 206 S. aureus-infected patients and 201 hospital-admitted control subjects

  4. Nasal carriage of Meticillin resistance Staphylococcus aureus ...

    African Journals Online (AJOL)

    Gemeda

    BACKGROUND: Staphylococcus aureus is one of the major causes of community and hospital acquired infections. The emergence of methicillin resistant strains of. Staphylococcus aureus in the hospitals and the community is a serious health problem. The aim of this study was to determine the nasal carriage and ...

  5. Antimicrobial resistant coagulase positive Staphylococcus aureus ...

    African Journals Online (AJOL)

    ADEYEYE

    Sokoto Journal of Veterinary Sciences, Volume 11 (Number 1). June, 2013. 51 ... Staphylococcus aureus is an Important agent of food poisoning. In many ..... enterotoxicity of Staphylococcus aureus isolated from the hands and nasal cavities of flight catering employees. Journal of Food. Protection, 11, 1487–1491. Hill JE ...

  6. Prevalence of methicillin resistant Staphylococcus aureus and ...

    African Journals Online (AJOL)

    ... Methicillin Resistant S. aureus (MRSA) in the studied population. Clinical isolates of S. aureus strains were collected from Medical Microbiology Unit of University College Hospital, Ibadan between May and October, 2012. The isolates were confirmed through growth on Mannitol Salt Agar (MSA) and tube coagulase test.

  7. Staphylococcus aureus and healthcare-associated infections

    NARCIS (Netherlands)

    Ekkelenkamp, M.B.|info:eu-repo/dai/nl/304817716

    2011-01-01

    Many medical procedures breach or suppress patients’ natural defences, leaving them vulnerable to infections which would not occur in healthy humans: “healthcare-associated infections”. Healthcare-associated infections caused by the bacterium Staphylococcus aureus (S. aureus) are probably the most

  8. Methicillin-Resistant Staphylococcus aureus Recovered from Healthcare- and Community-Associated Infections in Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed Abdel-Maksoud

    2016-01-01

    Full Text Available Background. Methicillin-resistant Staphylococcus aureus (MRSA has created significant epidemiological, infection-control, and therapeutic management challenges during the past three decades. Aim. To analyze the pattern of resistance of healthcare- and community-associated MRSA in Egypt and the trend of resistance of HA-MRSA over time (2005–2013. Methods. MRSA isolates were recovered from healthcare-associated (HA and community-associated (CA Staphylococcus aureus (S. aureus infections. They were tested against 11 antimicrobial discs and the minimal inhibitory concentration (MIC of vancomycin was determined. Inducible clindamycin resistance (iMLSB was also screened using D-test. Findings. Of 631 S. aureus, MRSA was identified in 343 (76.6% and 21 (11.5% of HA and CA S. aureus isolates, respectively. The proportion of HA-MRSA increased significantly from 48.6% in 2005 to 86.8% in 2013 (p value < 0.001. Multidrug resistance (MDR was observed in 85.8% of HA-MRSA and 48.6% of CA-MRSA. Vancomycin intermediate resistant S. aureus (VISA was detected in 1.2% of HA-MRSA and none was detected in CA-MRSA. Among HA-MRSA strains, 5.3% showed iMLSB compared to 9.5% among CA-MRSA. Conclusion. The upsurge of the prevalence rates of HA-MRSA over time is alarming and urges for an effective infection control strategy and continuous monitoring of antimicrobial use.

  9. Staphylococcus aureus α-toxin-dependent induction of host cell death by membrane-derived vesicles.

    Directory of Open Access Journals (Sweden)

    Bernard Thay

    Full Text Available Staphylococcus aureus causes a wide spectrum of infections in humans, ranging from superficial cutaneous infections, infections in the circum-oral region, to life-threatening bacteremia. It was recently demonstrated that Gram-positive organisms such as S. aureus liberate membrane-derived vesicles (MVs, which analogously to outer membrane vesicles (OMVs of Gram-negative bacteria can play a role in delivering virulence factors to host cells. In the present study we have shown that cholesterol-dependent fusion of S. aureus MVs with the plasma membrane represents a route for delivery of a key virulence factor, α-toxin (α-hemolysin; Hla to human cells. Most S. aureus strains produce this 33-kDa pore-forming protein, which can lyse a wide range of human cells, and induce apoptosis in T-lymphocytes. Our results revealed a tight association of biologically active α-toxin with membrane-derived vesicles isolated from S. aureus strain 8325-4. Concomitantly, α-toxin contributed to HeLa cell cytotoxicity of MVs, and was the main vesicle-associated protein responsible for erythrocyte lysis. In contrast, MVs obtained from an isogenic hla mutant were significantly attenuated with regards to both causing lysis of erythrocytes and death of HeLa cells. This is to our knowledge the first recognition of an S. aureus MV-associated factor contributing to host cell cytotoxicity.

  10. Adenosine derived from Staphylococcus aureus-engulfed macrophages functions as a potent stimulant for the induction of inflammatory cytokines in mast cells

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Kim, Chan-Hee; Ryu, Kyoung-Hwa

    2011-01-01

    In this study, we attempted to isolate novel mast cell-stimulating molecules from Staphylococcus aureus. Water-soluble extract of S. aureus cell lysate strongly induced human interleukin- 8 in human mast cell line-1 and mouse interleukin-6 in mouse bone marrow-derived mast cells. The active...... adenosine receptor blocker, verified that purified adenosine can induce interleukin-8 production via adenosine receptors on mast cells. Moreover, adenosine was purified from S. aureusengulfed RAW264.7 cells, a murine macrophage cell line, used to induce phagocytosis of S. aureus. These results show a novel...

  11. Staphylococcus aureus and hand eczema severity

    DEFF Research Database (Denmark)

    Haslund, P; Bangsgaard, N; Jarløv, J O

    2009-01-01

    BACKGROUND: The role of bacterial infections in hand eczema (HE) remains to be assessed. OBJECTIVES: To determine the prevalence of Staphylococcus aureus in patients with HE compared with controls, and to relate presence of S. aureus, subtypes and toxin production to severity of HE. METHODS......: Bacterial swabs were taken at three different visits from the hand and nose in 50 patients with HE and 50 controls. Staphylococcus aureus was subtyped by spa typing and assigned to clonal complexes (CCs), and isolates were tested for exotoxin-producing S. aureus strains. The Hand Eczema Severity Index...... was used for severity assessment. RESULTS: Staphylococcus aureus was found on the hands in 24 patients with HE and four controls (P

  12. The T Cell Response to Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Barbara M. Bröker

    2016-03-01

    Full Text Available Staphylococcus aureus (S. aureus is a dangerous pathogen and a leading cause of both nosocomial and community acquired bacterial infection worldwide. However, on the other hand, we are all exposed to this bacterium, often within the first hours of life, and usually manage to establish equilibrium and coexist with it. What does the adaptive immune system contribute toward lifelong control of S. aureus? Will it become possible to raise or enhance protective immune memory by vaccination? While in the past the S. aureus-specific antibody response has dominated this discussion, the research community is now coming to appreciate the role that the cellular arm of adaptive immunity, the T cells, plays. There are numerous T cell subsets, each with differing functions, which together have the ability to orchestrate the immune response to S. aureus and hence to tip the balance between protection and pathology. This review summarizes the state of the art in this dynamic field of research.

  13. ENTEROTOXIGENIC STAPHYLOCOCCUS AUREUS IN SHEEP RAW MILK

    Directory of Open Access Journals (Sweden)

    G. Giacinti

    2011-01-01

    Full Text Available A total of 366 raw milk samples from 30 sheep farms were examined quantitatively for Staphylococcus aureus. Enterotoxin production by strains of Staphylococcus aureus isolated was investigated. S. aureus was detected in 19 farms (63,3%. The ability to synthetise enterotoxins was found in ten strains (52,6%. Production of staphylococcal enterotoxins C (SEC was recorded in 6 (60% and production of SEC together with staphylococcal enterotoxin A (SEA in 4 (40% staphylococcal isolates. Raw milk products are vulnerable to contamination by S. aureus. Strategies to reduce the occurrence of S. aureus in bulk milk are of particular importance on farms where milk is used for raw milk products.

  14. Laboratory Mice Are Frequently Colonized with Staphylococcus aureus and Mount a Systemic Immune Response—Note of Caution for In vivo Infection Experiments

    Directory of Open Access Journals (Sweden)

    Silva Holtfreter

    2017-05-01

    Full Text Available Whether mice are an appropriate model for S. aureus infection and vaccination studies is a matter of debate, because they are not considered as natural hosts of S. aureus. We previously identified a mouse-adapted S. aureus strain, which caused infections in laboratory mice. This raised the question whether laboratory mice are commonly colonized with S. aureus and whether this might impact on infection experiments. Publicly available health reports from commercial vendors revealed that S. aureus colonization is rather frequent, with rates as high as 21% among specific-pathogen-free mice. In animal facilities, S. aureus was readily transmitted from parents to offspring, which became persistently colonized. Among 99 murine S. aureus isolates from Charles River Laboratories half belonged to the lineage CC88 (54.5%, followed by CC15, CC5, CC188, and CC8. A comparison of human and murine S. aureus isolates revealed features of host adaptation. In detail, murine strains lacked hlb-converting phages and superantigen-encoding mobile genetic elements, and were frequently ampicillin-sensitive. Moreover, murine CC88 isolates coagulated mouse plasma faster than human CC88 isolates. Importantly, S. aureus colonization clearly primed the murine immune system, inducing a systemic IgG response specific for numerous S. aureus proteins, including several vaccine candidates. Phospholipase C emerged as a promising test antigen for monitoring S. aureus colonization in laboratory mice. In conclusion, laboratory mice are natural hosts of S. aureus and therefore, could provide better infection models than previously assumed. Pre-exposure to the bacteria is a possible confounder in S. aureus infection and vaccination studies and should be monitored.

  15. Operon structure of Staphylococcus aureus.

    Science.gov (United States)

    ten Broeke-Smits, Nicole J P; Pronk, Tessa E; Jongerius, Ilse; Bruning, Oskar; Wittink, Floyd R; Breit, Timo M; van Strijp, Jos A G; Fluit, Ad C; Boel, C H Edwin

    2010-06-01

    In bacteria, gene regulation is one of the fundamental characteristics of survival, colonization and pathogenesis. Operons play a key role in regulating expression of diverse genes involved in metabolism and virulence. However, operon structures in pathogenic bacteria have been determined only by in silico approaches that are dependent on factors such as intergenic distances and terminator/promoter sequences. Knowledge of operon structures is crucial to fully understand the pathophysiology of infections. Presently, transcriptome data obtained from growth curves in a defined medium were used to predict operons in Staphylococcus aureus. This unbiased approach and the use of five highly reproducible biological replicates resulted in 93.5% significantly regulated genes. These data, combined with Pearson's correlation coefficients of the transcriptional profiles, enabled us to accurately compile 93% of the genome in operon structures. A total of 1640 genes of different functional classes were identified in operons. Interestingly, we found several operons containing virulence genes and showed synergistic effects for two complement convertase inhibitors transcribed in one operon. This is the first experimental approach to fully identify operon structures in S. aureus. It forms the basis for further in vitro regulation studies that will profoundly advance the understanding of bacterial pathophysiology in vivo.

  16. Necroptosis Promotes Staphylococcus aureus Clearance by Inhibiting Excessive Inflammatory Signaling

    Directory of Open Access Journals (Sweden)

    Kipyegon Kitur

    2016-08-01

    Full Text Available Staphylococcus aureus triggers inflammation through inflammasome activation and recruitment of neutrophils, responses that are critical for pathogen clearance but are associated with substantial tissue damage. We postulated that necroptosis, cell death mediated by the RIPK1/RIPK3/MLKL pathway, would function to limit pathological inflammation. In models of skin infection or sepsis, Mlkl−/− mice had high bacterial loads, an inability to limit interleukin-1b (IL-1b production, and excessive inflammation. Similarly, mice treated with RIPK1 or RIPK3 inhibitors had increased bacterial loads in a model of sepsis. Ripk3−/− mice exhibited increased staphylococcal clearance and decreased inflammation in skin and systemic infection, due to direct effects of RIPK3 on IL-1b activation and apoptosis. In contrast to Casp1/4−/− mice with defective S. aureus killing, the poor outcomes of Mlkl−/− mice could not be attributed to impaired phagocytic function. We conclude that necroptotic cell death limits the pathological inflammation induced by S. aureus.

  17. Preconditioning with Lipopolysaccharide or Lipoteichoic Acid Protects against Staphylococcus aureus Mammary Infection in Mice

    Directory of Open Access Journals (Sweden)

    Koen Breyne

    2017-07-01

    Full Text Available Staphylococcus aureus is one of the most causative agents of mastitis and is associated with chronic udder infections. The persistency of the pathogen is believed to be the result of an insufficient triggering of local inflammatory signaling. In this study, the preclinical mastitis model was used, aiming to evaluate if lipopolysaccharide (LPS or lipoteichoic acid (LTA preconditioning could aid the host in more effectively clearing or at least limiting a subsequent S. aureus infection. A prototypic Gram-negative virulence factor, i.e., LPS and Gram-positive virulence factor, i.e., LTA were screened whether they were able to boost the local immune compartment. Compared to S. aureus-induced inflammation, both toxins had a remarkable high potency to efficiently induce two novel selected innate immunity biomarkers i.e., lipocalin 2 (LCN2 and chitinase 3-like 1 (CHI3L1. When combining mammary inoculation of LPS or LTA prior to a local S. aureus infection, we were able to modulate the innate immune response, reduce local bacterial loads, and induce either LCN2 or CHI3L1 at 24 h post-infection. Clodronate depletion of mammary macrophages also identified that macrophages contribute only to a limited extend to the LPS/LTA-induced immunomodulation upon S. aureus infection. Based on histological neutrophil influx evaluation, concomitant local cytokine profiles and LCN2/CHI3L1 patterns, the macrophage-independent signaling plays a major role in the LPS- or LTA-pretreated S. aureus-infected mouse mammary gland. Our results highlight the importance of a vigilant microenvironment during the innate immune response of the mammary gland and offer novel insights for new approaches concerning effective immunomodulation against a local bacterial infection.

  18. Identification of a protective B-cell epitope of the Staphylococcus aureus GapC protein by screening a phage-displayed random peptide library.

    Science.gov (United States)

    Wang, Mengyao; Zhai, Lu; Yu, Wei; Wei, Yuhua; Wang, Lizi; Liu, Shuo; Li, Wanyu; Li, Xiaoting; Yu, Simiao; Chen, Xiaoting; Zhang, Hua; Chen, Jing; Feng, Zhenyue; Yu, Liquan; Cui, Yudong

    2018-01-01

    The impact of epidemic Staphylococcus aureus (S. aureus) on public health is increasing. Because of the abuse of antibiotics, the antibiotic resistance of S. aureus is increasing. Thus, there is an urgent need to develop new immunotherapies and immunoprophylaxes. Previous studies showed that the GapC protein of S. aureus, which is a surface protein with high glyceraldehyde 3-phosphate dehydrogenase activity, transferrin binding activity, and other biological activities, is highly conserved. GapC induces an effective humoral immune response in vivo. However, the B-cell epitopes of S. aureus GapC have not been well identified. Here we used the bioinformatics tools to analyze the sequence of GapC, and we generated protective anti-GapC monoclonal antibodies (mAbs). A protective mAb (1F4) showed strong specificity to GapC and the ability to induce macrophages to phagocytose S. aureus. We screened the motif 272GYTEDEIVSSD282, which was recognized by mAb 1F4, using a phage display system. Then, we used site-directed mutagenesis to identify key amino acids in the motif. Residues G272 D276 E277 I278 and V279 formed the core of the 272GYTEDEIVSSD282 motif. In addition, we showed that this epitope peptide induced a protective humoral immune response against S. aureus infection in immunized mice. Our results will be useful for the further study of epitope-based vaccines against S. aureus infection.

  19. Effects of niacin on Staphylococcus aureus internalization into bovine mammary epithelial cells by modulating NF-κB activation.

    Science.gov (United States)

    Wei, Zhengkai; Fu, Yunhe; Zhou, Ershun; Tian, Yuan; Yao, Minjun; Li, Yimeng; Yang, Zhengtao; Cao, Yongguo

    2014-01-01

    Niacin is a precursor of coenzymes NAD and NADP and plays a critical role in electron transfer during the metabolic process. In addition to its nutrimental function, niacin has long been used for the treatment of lipid disorders and cardiovascular disease. However, the effect of niacin on Staphylococcus aureus (S. aureus) internalization into bovine mammary epithelial cells (bMEC) remains unclear. Here we sought to examine the effect of niacin on S. aureus internalization into bovine mammary epithelial cells (bMEC) and to investigate the potential mechanism. In this study, the growth of S. aureus supplemented with niacin (0.5-2 mM) was monitored turbidimetrically at 600 nm for 24 h and cell viability was measured by MTT assay. Gentamicin protection assay was carried out to determine the effect of niacin on S. aureus internalization into bMEC. To determine the potential mechanism, tracheal antimicrobial peptide (TAP) and β-defensin (BNBD5) expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The activation of nuclear factor-kappa B (NF-κB) was determined by Western blotting. The results showed that niacin (0.5-2 mM) did not affect S. aureus growth and bMEC viability, whereas it inhibits S. aureus internalization ranging from 13% to 42% and down-regulated the mRNA expression of TAP and BNBD5 compared to the control group. No exactly relationship was discovered between S. aureus internalization into bMEC and antimicrobial peptide expression, while niacin inhibited S. aureus-induced NF-κB activation in a dose manner. These dates suggest that inhibiting NF-κB activation may be the potential mechanism of niacin on modulating S. aureus internalization into bMEC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Staphylococcus aureus resistente a vancomicina.

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Rodríguez

    2005-12-01

    Full Text Available Objetivo. Revisar la evolución y mecanismos moleculares de la resistencia de Staphylococcus aureus a vancomicina. Fuente de los datos. Se consultó la base de datos MEDLINE y se seleccionaron artículos tipo reportes de caso, estudios bioquímicos, de microscopía electrónica y biología molecular pertinentes. Síntesis. Después de casi 40 años de eficacia ininterrumpida de la vancomicina, en 1997 se reportaron los primeros casos de fracaso terapéutico debido a cepas de Staphylococcus aureus con resistencia intermedia, denominadas VISA (concentración inhibitoria mínima, CIM, 8 a 16 ?g/ml, así como a cepas con resistencia heterogénea hVISA (CIM global = 4 ?g/ml, pero con subpoblaciones VISA, en las cuales la resistencia está mediada por engrosamiento de la pared celular y disminución de su entrecruzamiento, lo que afecta la llegada del antibiótico al blanco principal, los monómeros del peptidoglicano en la membrana plasmática. En 2002 se aisló la primera de las 3 cepas reportadas hasta la fecha con resistencia total al antibiótico, denominadas VRSA (CIM>32 ?g/ml, en las que se encontró el transposón Tn1546 proveniente de Enterococcus spp, responsable del reemplazo de la terminación D-Ala-D-Ala por D-Ala-Dlactato en los precursores de la pared celular con pérdida de la afinidad por el glicopéptido. Conclusiones. La resistencia a vancomicina es una realidad en S. aureus, mediada en el caso de VISA por alteraciones en la pared celular que atrapan el antibiótico antes de llegar al sitio de acción, y en el caso de VRSA, por transferencia desde Enterococcus spp. de genes que llevan a la modificación del blanco molecular.

  1. Exfoliative Toxins of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Michal Bukowski

    2010-05-01

    Full Text Available Staphylococcus aureus is an important pathogen of humans and livestock. It causes a diverse array of diseases, ranging from relatively harmless localized skin infections to life-threatening systemic conditions. Among multiple virulence factors, staphylococci secrete several exotoxins directly associated with particular disease symptoms. These include toxic shock syndrome toxin 1 (TSST-1, enterotoxins, and exfoliative toxins (ETs. The latter are particularly interesting as the sole agents responsible for staphylococcal scalded skin syndrome (SSSS, a disease predominantly affecting infants and characterized by the loss of superficial skin layers, dehydration, and secondary infections. The molecular basis of the clinical symptoms of SSSS is well understood. ETs are serine proteases with high substrate specificity, which selectively recognize and hydrolyze desmosomal proteins in the skin. The fascinating road leading to the discovery of ETs as the agents responsible for SSSS and the characterization of the molecular mechanism of their action, including recent advances in the field, are reviewed in this article.

  2. Complete and SOS-mediated response of Staphylococcus aureus to the antibiotic ciprofloxacin.

    Science.gov (United States)

    Cirz, Ryan T; Jones, Marcus B; Gingles, Neill A; Minogue, Timothy D; Jarrahi, Behnam; Peterson, Scott N; Romesberg, Floyd E

    2007-01-01

    Staphylococcus aureus infections can be difficult to treat due to both multidrug resistance and the organism's remarkable ability to persist in the host. Persistence and the evolution of resistance may be related to several complex regulatory networks, such as the SOS response, which modifies transcription in response to environmental stress. To understand how S. aureus persists during antibiotic therapy and eventually emerges resistant, we characterized its global transcriptional response to ciprofloxacin. We found that ciprofloxacin induces prophage mobilization as well as significant alterations in metabolism, most notably the up-regulation of the tricarboxylic acid cycle. In addition, we found that ciprofloxacin induces the SOS response, which we show, by comparison of a wild-type strain and a non-SOS-inducible lexA mutant strain, includes the derepression of 16 genes. While the SOS response of S. aureus is much more limited than those of Escherichia coli and Bacillus subtilis, it is similar to that of Pseudomonas aeruginosa and includes RecA, LexA, several hypothetical proteins, and a likely error-prone Y family polymerase whose homologs in other bacteria are required for induced mutation. We also examined induced mutation and found that either the inability to derepress the SOS response or the lack of the LexA-regulated polymerase renders S. aureus unable to evolve antibiotic resistance in vitro in response to UV damage. The data suggest that up-regulation of the tricarboxylic acid cycle and induced mutation facilitate S. aureus persistence and evolution of resistance during antibiotic therapy.

  3. Aggravation of bronchial eosinophilia in mice by nasal and bronchial exposure to Staphylococcus aureus enterotoxin B

    NARCIS (Netherlands)

    Hellings, P. W.; Hens, G.; Meyts, I.; Bullens, D.; Vanoirbeek, J.; Gevaert, P.; Jorissen, M.; Ceuppens, J. L.; Bachert, C.

    2006-01-01

    The role of bacterial enterotoxins like Staphylococcus aureus enterotoxin B (SEB) in allergic asthma remains unknown. We used a mouse model of airway allergy to study the effects of nasal or bronchial contact with SEB on bronchial allergic inflammation. The features of allergic asthma were induced

  4. Development of the immune response in pneumonia due to Staphylococcus aureus (part 1

    Directory of Open Access Journals (Sweden)

    A.E. Abaturov

    2017-03-01

    Full Text Available The literature review presents modern data on the pathogen-associated molecular structures of Staphylococcus aureus and its role in the occurrence of pneumonia: activation and modulation of the immune response, oxidative and metabolic stress, apoptosis. Particular attention is paid to the factors of virulence of the pathogen, which can induce an inflammatory process without activating the image-recognition receptors.

  5. A compound magnetic field generating system for targeted killing of Staphylococcus aureus by magnetotactic bacteria in a microfluidic chip

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Linjie; Chen, Changyou [Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); France-China Bio-Mineralization and Nano-Structures Laboratory, Beijing (China); Wang, Pingping; Chen, Chuanfang [Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); France-China Bio-Mineralization and Nano-Structures Laboratory, Beijing (China); Wu, Long-Fei [Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Laboratoire de Chimie Bactérienne, UMR7283, Aix-Marseille University, Institut de Microbiologie de la Méditerranée, CNRS, Marseille (France); Song, Tao, E-mail: songtao@mail.iee.ac.cn [Beijing Key Laboratory of Bioelectromagnetism, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); France-China Bio-Mineralization and Nano-Structures Laboratory, Beijing (China)

    2017-04-01

    A compound magnetic field generating system was built to kill Staphylococcus aureus (S. aureus) by magnetotactic bacteria (MTB) in a microfluidic chip in this paper. The system was consisted of coil pairs, a switch circuit, a control program and controllable electrical sources. It could produce a guiding magnetic field (gMF) of ±1 mT along arbitrary direction in the horizontal plane, a rotating magnetic field (rMF) and a swing magnetic field (sMF, 2 Hz, 10 mT) by controlling the currents. The gMF was used to guide MTB swimming to the S. aureus pool in the microfluidic chip, and then the rMF enhanced the mixture of S. aureus and MTB cells, therefore beneficial to the attachments of them. Finally, the sMF was used to induce the death of S. aureus via MTB. The results showed that MTB could be navigated by the gMF and that 47.1% of S. aureus were killed when exposed to the sMF. It provides a new solution for the targeted treatment of infected diseases and even cancers. - Highlights: • We built a system which generated a compound magnetic field in one device. • The compoud magnetic field includes guiding, rotating and swing magnetic fields. • MTB was guided and S. aureus attached to MTB was killed in the same device.

  6. Staphylococcus aureus α-hemolysin mediates virulence in a murine model of severe pneumonia through activation of the NLRP3 inflammasome.

    Science.gov (United States)

    Kebaier, Chahnaz; Chamberland, Robin R; Allen, Irving C; Gao, Xi; Broglie, Peter M; Hall, Joshua D; Jania, Corey; Doerschuk, Claire M; Tilley, Stephen L; Duncan, Joseph A

    2012-03-01

    Staphylococcus aureus is a dangerous pathogen that can cause necrotizing infections characterized by massive inflammatory responses and tissue destruction. Staphylococcal α-hemolysin is an essential virulence factor in severe S. aureus pneumonia. It activates the nucleotide-binding domain and leucine-rich repeat containing gene family, pyrin domain containing 3 (NLRP3) inflammasome to induce production of interleukin-1β and programmed necrotic cell death. We sought to determine the role of α-hemolysin-mediated activation of NLRP3 in the pathogenesis of S. aureus pneumonia. We show that α-hemolysin activates the NLRP3 inflammasome during S. aureus pneumonia, inducing necrotic pulmonary injury. Moreover, Nlrp3(-/-) mice have less-severe pneumonia. Pulmonary injury induced by isolated α-hemolysin or live S. aureus is independent of interleukin-1β signaling, implicating NLRP3-induced necrosis in the pathogenesis of severe infection. This work demonstrates the exploitation of host inflammatory signaling by S. aureus and suggests the NLRP3 inflammasome as a potential target for pharmacologic interventions in severe S. aureus infections.

  7. Methicillin-resistant Staphylococcus aureus (MRSA)

    Science.gov (United States)

    ... resistant Staphylococcus aureus; Hospital-acquired MRSA (HA-MRSA); Staph - MRSA; Staphylococcal - MRSA ... Most staph germs are spread by skin-to-skin contact (touching). A doctor, nurse, other health care provider, or ...

  8. Community acquired Staphylococcus aureus meningitis in adults

    NARCIS (Netherlands)

    Brouwer, Matthijs C.; Keizerweerd, Gabriella D.; de Gans, Jan; Spanjaard, Lodewijk; van de Beek, Diederik

    2009-01-01

    We present 9 patients with community acquired Staphylococcus aureus meningitis. Foci of infection outside the central nervous system were present in 8 (89%) patients, mostly endocarditis and pneumonia. Cardiorespiratory complications occurred frequently and 6 patients died (67%). Identification and

  9. Misidentification of methicillinresistant Staphylococcus aureus (MRSA)

    African Journals Online (AJOL)

    , Libya using current testing methods. Methods: One hundred and seventy S. aureus isolates previously identified as MRSA were obtained from three hospitals in Tripoli. All isolates were reidentified by culturing on mannitol salt agar, API 20 ...

  10. The intramammary efficacy of first generation cephalosporins against Staphylococcus aureus mastitis in mice.

    Science.gov (United States)

    Demon, Dieter; Ludwig, Carolin; Breyne, Koen; Guédé, David; Dörner, Julia-Charlotte; Froyman, Robrecht; Meyer, Evelyne

    2012-11-09

    Staphylococcus aureus-induced mastitis in cattle causes important financial losses in the dairy industry due to lower yield and bad milk quality. Although S. aureus is susceptible to many antimicrobials in vitro, treatment often fails to cure the infected udder. Hence, comprehensive evaluation of antimicrobials against S. aureus mastitis is desirable to direct treatment strategies. The mouse mastitis model is an elegant tool to evaluate antimicrobials in vivo while circumventing the high costs associated with bovine experiments. An evaluation of the antimicrobial efficacy of the intramammary (imam) applied first generation cephalosporins cefalexin, cefalonium, cefapirin and cefazolin, was performed using the S. aureus mouse mastitis model. In vivo determination of the effective dose 2log(10) (ED(2log10)), ED(4log10), protective dose 50 (PD(50)) and PD(100) in mouse mastitis studies, support that in vitro MIC data of the cephalosporins did not fully concur with the in vivo clinical outcome. Cefazolin was shown to be the most efficacious first generation cephalosporin to treat S. aureus mastitis whereas the MIC data indicate that cefalonium and cefapirin were more active in vitro. Changing the excipient for imam application from mineral oil to miglyol 812 further improved the antimicrobial efficacy of cefazolin, confirming that the excipient can influence the in vivo efficacy. Additionally, statistical analysis of the variation of S. aureus-infected, excipient-treated mice from fourteen studies emphasizes the strength of the mouse mastitis model as a fast, cost-effective and highly reproducible screening tool to assess the efficacy of antimicrobial compounds against intramammary S. aureus infection. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Silkworm Apolipophorin Protein Inhibits Staphylococcus aureus Virulence*

    Science.gov (United States)

    Hanada, Yuichi; Sekimizu, Kazuhisa; Kaito, Chikara

    2011-01-01

    Silkworm hemolymph inhibits hemolysin production by Staphylococcus aureus. We purified a factor in the silkworm hemolymph responsible for this inhibitory activity. The final fraction with the greatest specific activity contained 220- and 74-kDa proteins. Determination of the N-terminal amino acid sequence revealed that the 220- and 74-kDa proteins were apolipophorin I and apolipophorin II, respectively, indicating that the factor was apolipophorin (ApoLp). The purified ApoLp fraction showed decreased expression of S. aureus hla encoding α-hemolysin, hlb encoding β-hemolysin, saeRS, and RNAIII, which activate the expression of these hemolysin genes. Injection of an anti-ApoLp antibody into the hemolymph increased the sensitivity of silkworms to the lethal effect of S. aureus. Hog gastric mucin, a mammalian homologue of ApoLp, decreased the expression of S. aureus hla and hlb. These findings suggest that ApoLp in the silkworm hemolymph inhibits S. aureus virulence and contributes to defense against S. aureus infection and that its activity is conserved in mammalian mucin. PMID:21937431

  12. Receptor mediated agglutination of human spermatozoa by spermagglutinating factor isolated from Staphylococcus aureus.

    Science.gov (United States)

    Kaur, Siftjit; Prabha, Vijay; Sarwal, Abha

    2010-12-01

    We examined spermagglutinating factor isolated from Staphylococcus aureus for evidence of receptor mediated agglutination of human spermatozoa. Binding to spermatozoa by spermagglutinating factor isolated from S. aureus with a high degree of specificity indicates receptor-ligand interaction. To examine this interaction we isolated and purified the ligand and the receptor. To assess receptor mediated agglutination of spermatozoa further we blocked spermagglutination induced by spermagglutinating factor in the presence of receptor. Spermagglutinating factor induced spermagglutination was competitively inhibited by adding purified receptor, indicating that sperm agglutinating factor isolated from S. aureus attaches to specific receptors on human spermatozoa. The spermagglutinating factor receptor was a protein with a molecular weight of approximately 57 kDa. Spermagglutinating factor induced spermagglutination and at higher concentrations had a spermicidal effect, which was inhibited by introducing the receptor. As observed on scanning electron microscopy studies, incubating spermatozoa with spermagglutinating factor showed profound morphological alterations. However, spermatozoa with normal morphology were noted when incubated with spermagglutinating factor in the presence of receptor, indicating that morphological alterations may account for spermatozoa agglutination by spermagglutinating factor. Results suggest that spermagglutinating factor isolated from S. aureus may bind specifically to sperm surface receptor sites before causing spermagglutination. Copyright © 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  13. Antibiotic resistance and biofilm production among the strains of Staphylococcus aureus isolated from pus/wound swab samples in a tertiary care hospital in Nepal.

    Science.gov (United States)

    Belbase, Ankit; Pant, Narayan Dutt; Nepal, Krishus; Neupane, Bibhusan; Baidhya, Rikesh; Baidya, Reena; Lekhak, Binod

    2017-03-23

    The increasing drug resistance along with inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of Staphylococcus aureus are present as the serious problems to the successful treatment of the infections caused by S. aureus. So, the main objectives of this study were to determine the antimicrobial susceptibility patterns along with the rates of inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of S. aureus isolated from pus/wound swab samples. A total of 830 non-repeated pus/wound swab samples were processed using standard microbiological techniques. The colonies grown were identified on the basis of colony morphology, Gram's stain and biochemical tests. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion technique. Detection of inducible clindamycin resistance was performed by D test, while detection of methicillin resistant S. aureus (MRSA) was performed by determination of minimum inhibitory concentration of oxacillin by agar dilution method. Similarly, detection of biofilm formation was performed by microtiter plate method. Strains showing resistance to three or more than three different classes of antibiotics were considered multidrug resistant. Total 76 samples showed the growth of S. aureus, among which 36 (47.4%) contained MRSA and 17 (22.4%) samples were found to have S. aureus showing inducible clindamycin resistance. Among the S. aureus isolated from outpatients, 41.9% were MRSA. Highest rates of susceptibility of S. aureus were seen toward linezolid (100%) and vancomycin (100%). Similarly, S. aureus isolated from 35 (46.1%) samples were found to be biofilm producers. Higher rate of inducible clindamycin resistance was seen among MRSA in comparison to methicillin susceptible S. aureus (MSSA). Similarly, higher rates of multidrug resistance and methicillin resistance were found among biofilm producing strains in comparison to biofilm non

  14. Filaments in curved streamlines: rapid formation of Staphylococcus aureus biofilm streamers

    Science.gov (United States)

    Kim, Minyoung Kevin; Drescher, Knut; Pak, On Shun; Bassler, Bonnie L.; Stone, Howard A.

    2014-06-01

    Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development of S. aureus. We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in flows with curved streamlines to bridge the distances between corners, we developed a mathematical model based on resistive force theory of slender filaments. Understanding physical aspects of biofilm formation of S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen.

  15. Filaments in curved flow: Rapid formation of Staphylococcus aureus biofilm streamers

    Science.gov (United States)

    Kim, Min Young; Drescher, Knut; Pak, On Shun; Bassler, Bonnie L.; Stone, Howard A.

    2014-03-01

    Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development in S. aureus.We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in curved flow to bridge the distances between corners, we developed a mathematical model based on resistive force theory and slender filaments. Understanding physical aspects of biofilm formation in S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen.

  16. Antimicrobial Activity of Punicalagin Against Staphylococcus aureus and Its Effect on Biofilm Formation.

    Science.gov (United States)

    Xu, Yunfeng; Shi, Chao; Wu, Qian; Zheng, Zhiwei; Liu, Peifeng; Li, Guanghui; Peng, Xiaoli; Xia, Xiaodong

    2017-05-01

    Punicalagin, one of the main active compounds in pomegranate peel, has been reported to possess many properties, including antioxidant, antimicrobial, antiviral, and immunosuppressive activities. The aim of this study was to investigate the antibacterial effect of punicalagin against Staphylococcus aureus and possible mode of action. Growth inhibition activity was examined by the agar diffusion method. Then agar dilution method was adopted to determine the minimum inhibitory concentration (MIC). The effects of punicalagin on cell membrane were assessed by measuring potassium efflux. Morphological changes of S. aureus were assessed by scanning and transmission electron microscopy. Crystal violet assay was applied to investigate antibiofilm activity of punicalagin. Punicalagin exhibited good antistaphylococcal effect with an MIC of 0.25 mg/mL. An increase of potassium efflux was observed when cells were treated with punicalagin at 2 × MIC. Punicalagin induced morphological damages to the cell membrane. Moreover, punicalagin exerted a remarkable inhibitory effect on biofilm formation of S. aureus. These findings suggest that punicalagin has antimicrobial and antibiofilm activities against S. aureus and may have potential application to control S. aureus contamination in food industry.

  17. Observations on Arthritis in Broiler Breeder Chickens Experimentally Infected with Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Chang-Qin Gu§, Xue-Ying Hu§, Chang-Qing Xie1, Wan-Po Zhang, De-Hai Wang, Quan Zhou and Guo-Fu Cheng1*

    2013-04-01

    Full Text Available Staphylococcus aureus is the most common cause of bacterial arthritis in broiler breeder chickens. In this study, we established a model of broiler breeder chicken arthritis inoculated with Staph. aureus isolated from a spontaneously occurring bacterial arthritis in chickens. We evaluated the model by bacteriology, serology, pathology, and immunology. The results showed that 2.5 × 109 cfu Staph. aureus injected into the right joint cavity can successfully induce a chicken arthritis model. The majority of the infected chickens suffered lameness and joint swelling at 3 days post-inoculation (DPI. The death peak time was on 7 DPI and the mortality rate was 51.1%. Staph. aureus can be continuously isolated from the blood and left joint synovial fluid of the infected chickens. Lesions found on the infected chickens consisted of swollen joints full of caseous exudates, cartilage injury, and synovial membrane thickening with infiltration of inflammatory cells. The center of the lesion contained many round bacterial cocci. With joint injury aggravation, intra-articular hyaluronic acid gradually decreased, and serum interleukin-6 became significantly higher compared with the control (P<0.01 from 3 DPI. The results indicated that the chicken models of Staph. aureus-mediated arthritis were successful, and can be used to gain a better understanding of the host-bacterium relationship.

  18. Nigribactin, a Novel Siderophore from Vibrio nigripulchritudo, Modulates Staphylococcus aureus Virulence Gene Expression

    Directory of Open Access Journals (Sweden)

    Lone Gram

    2012-11-01

    Full Text Available Staphylococcus aureus is a serious human pathogen that employs a number of virulence factors as part of its pathogenesis. The purpose of the present study was to explore marine bacteria as a source of compounds that modulate virulence gene expression in S. aureus. During the global marine Galathea 3 expedition, a strain collection was established comprising bacteria that express antimicrobial activity against Vibrio anguillarum and/or Staphylococcus aureus. Within this collection we searched colony material, culture supernatants, and cell extracts for virulence modulating activity showing that 68 out of 83 marine bacteria (affiliated with the Vibrionaceae and Pseudoalteromonas sp. influenced expression of S. aureus hla encoding α-hemolysin toxin and/or spa encoding Protein A. The isolate that upon initial screening showed the highest degree of interference (crude ethyl acetate extract was a Vibrio nigripulchritudo. Extraction, purification and structural elucidation revealed a novel siderophore, designated nigribactin, which induces spa transcription. The effect of nigribactin on spa expression is likely to be independent from its siderophore activity, as another potent siderophore, enterobactin, failed to influence S. aureus virulence gene expression. This study shows that marine microorganisms produce compounds with potential use in therapeutic strategies targeting virulence rather than viability of human pathogens.

  19. Bacterial Nitric Oxide Synthase Is Required for the Staphylococcus aureus Response to Heme Stress.

    Science.gov (United States)

    Surdel, Matthew C; Dutter, Brendan F; Sulikowski, Gary A; Skaar, Eric P

    2016-08-12

    Staphylococcus aureus is a pathogen that causes significant morbidity and mortality worldwide. Within the vertebrate host, S. aureus requires heme as a nutrient iron source and as a cofactor for multiple cellular processes. Although required for pathogenesis, excess heme is toxic. S. aureus employs a two-component system, the heme sensor system (HssRS), to sense and protect against heme toxicity. Upon activation, HssRS induces the expression of the heme-regulated transporter (HrtAB), an efflux pump that alleviates heme toxicity. The ability to sense and respond to heme is critical for the pathogenesis of numerous Gram-positive organisms, yet the mechanism of heme sensing remains unknown. Compound '3981 was identified in a high-throughput screen as an activator of staphylococcal HssRS that triggers HssRS independently of heme accumulation. '3981 is toxic to S. aureus; however, derivatives of '3981 were synthesized that lack toxicity while retaining HssRS activation, enabling the interrogation of the heme stress response without confounding toxic effects of the parent molecule. Using '3981 derivatives as probes of the heme stress response, numerous genes required for '3981-induced activation of HssRS were uncovered. Specifically, multiple genes involved in the production of nitric oxide were identified, including the gene encoding bacterial nitric oxide synthase (bNOS). bNOS protects S. aureus from oxidative stress imposed by heme. Taken together, this work identifies bNOS as crucial for the S. aureus heme stress response, providing evidence that nitric oxide synthesis and heme sensing are intertwined.

  20. Staphylococcus aureus Colonization: Modulation of Host Immune Response and Impact on Human Vaccine Design

    Science.gov (United States)

    Brown, Aisling F.; Leech, John M.; Rogers, Thomas R.; McLoughlin, Rachel M.

    2014-01-01

    In apparent contrast to its invasive potential Staphylococcus aureus colonizes the anterior nares of 20–80% of the human population. The relationship between host and microbe appears particularly individualized and colonization status seems somehow predetermined. After decolonization, persistent carriers often become re-colonized with their prior S. aureus strain, whereas non-carriers resist experimental colonization. Efforts to identify factors facilitating colonization have thus far largely focused on the microorganism rather than on the human host. The host responds to S. aureus nasal colonization via local expression of anti-microbial peptides, lipids, and cytokines. Interplay with the co-existing microbiota also influences colonization and immune regulation. Transient or persistent S. aureus colonization induces specific systemic immune responses. Humoral responses are the most studied of these and little is known of cellular responses induced by colonization. Intriguingly, colonized patients who develop bacteremia may have a lower S. aureus-attributable mortality than their non-colonized counterparts. This could imply a staphylococcal-specific immune “priming” or immunomodulation occurring as a consequence of colonization and impacting on the outcome of infection. This has yet to be fully explored. An effective vaccine remains elusive. Anti-S. aureus vaccine strategies may need to drive both humoral and cellular immune responses to confer efficient protection. Understanding the influence of colonization on adaptive response is essential to intelligent vaccine design, and may determine the efficacy of vaccine-mediated immunity. Clinical trials should consider colonization status and the resulting impact of this on individual patient responses. We urgently need an increased appreciation of colonization and its modulation of host immunity. PMID:24409186

  1. The effect of immunoregulation of Streptococcus lactis L16 strain upon Staphylococcus aureus infection.

    Science.gov (United States)

    Wang, Maopeng; Gong, Shengjie; Du, Shouwen; Zhu, Yilong; Rong, Fengjun; Pan, Rongrong; Di, Yang; Li, Chang; Ren, Dayong; Jin, Ningyi

    2017-06-02

    Staphylococcus aureus is an important pathogen that causes various infections in medical facilities. However, resistance to multiple drugs has made this infection difficult to manage. Thus, new therapeutic strategies are urgently needed to solve this worldwide public health problem. The Streptococcus lactis L16 strain was isolated from the fermented hot chili sauce. To explore whether it can be used as a protective agent against S. aureus infection, we designed a mouse model of S. aureus infection to evaluate the therapeutic potency of S. lactis. Mice were grouped into pre-(P) and post-(T) S. aureus infection groups following oral administration of S. lactis L16. The protection and treatment effects were assessed by examining body weight, internal organ weight, serum cytokines and intestinal secretory IgA alternations. Oral administration of the S. lactis L16 strain reduced the loss of body weight in mice post-infection and alleviated infection-induced hepatomegaly. In particular, the PL16 group (protection with L16) showed more effective resistance to S. aureus than the TL16 group (treatment with L16). The level of serum cytokine interferon gamma following oral administration of the L16 strain was remarkably increased during infection, as were interleukin-4 levels during convalescence. The probiotic L16 strain induced more sIgA production than S. aureus. Our data suggest that S. lactis L16 is an effective strain with anti-Staphylococcus activity. By regulating the Th1/Th2 response, S. lactis can effectively reduce lesions from infection, indicating its therapeutic potential in overcoming antibiotic resistance in this mouse infection model that mimics infections observed in humans.

  2. Staphylococcus aureus seroproteomes discriminate ruminant isolates causing mild or severe mastitis

    Science.gov (United States)

    2011-01-01

    Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ewe and mice experimental mastitis. Notably, they reproduced mild (O46) or severe (O11) mastitis in ewes. Ewe sera were used to identify staphylococcal immunoreactive proteins commonly or differentially produced during infections of variable severity and to define core and accessory seroproteomes. Such SERological Proteome Analysis (SERPA) allowed the identification of 89 immunoreactive proteins, of which only 52 (58.4%) were previously identified as immunogenic proteins in other staphylococcal infections. Among the 89 proteins identified, 74 appear to constitute the core seroproteome. Among the 15 remaining proteins defining the accessory seroproteome, 12 were specific for strain O11, 3 were specific for O46. Distribution of one protein specific for each mastitis severity was investigated in ten other strains isolated from subclinical or clinical mastitis. We report here for the first time the identification of staphylococcal immunogenic proteins common or specific to S. aureus strains responsible for mild or severe mastitis. These findings open avenues in S. aureus mastitis studies as some of these proteins, expressed in vivo, are likely to account for the success of S. aureus as a pathogen of the ruminant mammary gland. PMID:21324116

  3. Short communication: Effects of lactose and milk on the expression of biofilm-associated genes in Staphylococcus aureus strains isolated from a dairy cow with mastitis.

    Science.gov (United States)

    Xue, Ting; Chen, Xiaolin; Shang, Fei

    2014-10-01

    Staphylococcus aureus is the main etiological organism responsible for bovine mastitis. The ability of S. aureus to form biofilms plays an important role in the pathogenesis of mastitis. Biofilm formation in S. aureus is associated with the production of polysaccharide intercellular adhesin (PIA) protein and several other proteins. Several environmental factors, including glucose, osmolarity, oleic acid, temperature, and anaerobiosis, have been reported to affect biofilm formation in S. aureus. This study investigated the influence of lactose and milk on the biofilm formation capacity of 2 clinical bovine isolates of S. aureus. We found that lactose increased biofilm formation predominantly by inducing PIA production, whereas milk increased biofilm formation through PIA as well as by increasing the production of other biofilm-associated proteins, which might be mediated by the transcriptional regulators intercellular adhesion regulator (icaR) and repressor of biofilm (rbf). Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Changes in Holstein cow milk and serum proteins during intramammary infection with three different strains of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Robert Claude

    2011-09-01

    Full Text Available Abstract Background Staphylococcus aureus is one of the most prevalent pathogens to cause mastitis in dairy cattle. Intramammary infection of dairy cows with S. aureus is often subclinical, due to the pathogen's ability to evade the innate defense mechanisms, but this can lead to chronic infection. A sub-population of S. aureus, known as small colony variant (SCV, displays atypical phenotypic characteristics, causes persistent infections, and is more resistant to antibiotics than parent strains. Therefore, it was hypothesized that the host immune response will be different for SCV than its parental or typical strains of S. aureus. In this study, the local and systemic immune protein responses to intramammary infection with three strains of S. aureus, including a naturally occurring bovine SCV strain (SCV Heba3231, were characterized. Serum and casein-depleted milk cytokine levels (interleukin-8, interferon-γ, and transforming growth factor-β1, as well as serum haptoglobin concentrations were monitored over time after intramammary infection with each of the three S. aureus strains. Furthermore, comparative proteomics was used to evaluate milk proteome profiles during acute and chronic phases of S. aureus intramammary infection. Results Serum IL-8, IFN-γ, and TGF-β1 responses differed in dairy cows challenged with different strains of S. aureus. Changes in overall serum haptoglobin concentrations were observed for each S. aureus challenge group, but there were no significant differences observed between groups. In casein-depleted milk, strain-specific differences in the host IFN-γ response were observed, but inducible IL-8 and TGF-β1 concentrations were not different between groups. Proteomic analysis of the milk following intramammary infection revealed unique host protein expression profiles that were dependent on the infecting strain as well as phase of infection. Notably, the protein, component-3 of the proteose peptone (CPP3, was

  5. Identification of CD4+ T-cell epitopes on iron-regulated surface determinant B of Staphylococcus aureus.

    Science.gov (United States)

    Yu, Simiao; Zhang, Hua; Yao, Di; Liu, Wei; Wang, Xintong; Chen, Xiaoting; Wei, Yuhua; Zhang, Zhenghai; Wang, Jiannan; Yu, Liquan; Sun, Hunan; Wu, Zhijun; Yu, Yongzhong; Song, Baifen; Ma, Jinzhu; Tong, Chunyu; Cui, Yudong

    2015-12-01

    Iron-regulated surface determinant B (IsdB) of Staphylococcus aureus (S. aureus) is a highly conserved surface protein that can induce protective CD4(+) T-cell immune response. A pivotal role of CD4(+) T-cells in effective immunity against S. aureus infection has been proved, but CD4(+) T-cell epitopes on the S. aureus IsdB have not been well identified. In this study, MHC binding assay was firstly used to predict CD4(+) T-cell epitopes on S. aureus IsdB protein, and six peptides were synthesized to validate the probable epitopes. Two novel IsdB CD4(+) T-cell epitopes, P1 (residues 159-178) and P4 (residues 287-306), were for the first time identified using CD4(+) T-cells obtained from IsdB-immunized C57BL/6 (H-2(b)) and BALB/c (H-2(d)) mice spleen based on cell proliferation and cytokines response. The results showed that P1 and P4 emulsified in Freund's adjuvant (FA) induced much higher cell proliferation compared with PBS emulsified in FA. CD4(+) T-cells stimulated with peptides P1 and P4 secreted significantly higher levels of IFN-γ and IL-17A. However, the level of the cytokine IL-4 almost remained unchanged, suggesting that P1 and P4 preferentially elicited polarized Th1-type responses. In addition, BALB/c mice just respond to P4 not P1, while C57BL/6 mice respond to P1 not P4, implying that epitope P1 and P4 were determined as H-2(b) and H-2(d) restricted epitope, respectively. Taken together, our data may provide an explanation of the IsdB-induced protection against S. aureus and highlight the possibility of developing the epitope-based vaccine against the S. aureus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Evolution of methicillin-resistant Staphylococcus aureus towards increasing resistance

    DEFF Research Database (Denmark)

    Strommenger, Birgit; Bartels, Mette Damkjær; Kurt, Kevin

    2014-01-01

    To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300....

  7. Prevalence of infective endocarditis in patients with Staphylococcus aureus bacteraemia

    DEFF Research Database (Denmark)

    Rasmussen, Rasmus V; Høst, Ulla; Arpi, Magnus

    2011-01-01

    Aims Staphylococcus aureus infective endocarditis (IE) is a critical medical condition associated with a high morbidity and mortality. In the present study, we prospectively evaluated the importance of screening with echocardiography in an unselected S. aureus bacteraemia (SAB) population. Methods...

  8. Staphylococcus aureus pathogenesis in diverse host environments

    Science.gov (United States)

    Balasubramanian, Divya; Harper, Lamia; Shopsin, Bo; Torres, Victor J.

    2017-01-01

    Abstract Staphylococcus aureus is an eminent human pathogen that can colonize the human host and cause severe life-threatening illnesses. This bacterium can reside in and infect a wide range of host tissues, ranging from superficial surfaces like the skin to deeper tissues such as in the gastrointestinal tract, heart and bones. Due to its multifaceted lifestyle, S. aureus uses complex regulatory networks to sense diverse signals that enable it to adapt to different environments and modulate virulence. In this minireview, we explore well-characterized environmental and host cues that S. aureus responds to and describe how this pathogen modulates virulence in response to these signals. Lastly, we highlight therapeutic approaches undertaken by several groups to inhibit both signaling and the cognate regulators that sense and transmit these signals downstream. PMID:28104617

  9. Methicillin-resistant Staphylococcus aureus in minas frescal cheese: evaluation of classic enterotoxin genes, antimicrobial resistance and clonal diversity.

    Science.gov (United States)

    Gonzalez, Alice Gonçalves Martins; Marques, Leila Márcia Peres; Gomes, Marcel da Silva Amorim; Beltrão, Jhonathan Campos do Couto; Pinheiro, Marcos Gabriel; Esper, Luciana Maria Ramires; Paula, Geraldo Renato de; Teixeira, Lenise Arneiro; Aguiar-Alves, Fábio

    2017-12-15

    This study aimed to investigate classical enterotoxin (sea to see) and mecA genes, by polymerase chain reaction and anitimicrobial susceptibility, by disk diffusion test of Staphylococcus aureus isolated from minas frescal cheese (MFC). All methicillin-resistant S. aureus (MRSA) isolates were investigated for the presence of Panton-Valentine leukocidin (PVL) genes and clonal diversity. Thirty-one S. aureus were isolated from four MFC samples. Seven (22.6%) S. aureus carried mecA gene and two of them carried enterotoxin genes seb/sec and sea/seb. Five (16.1%) S. aureus isolates showed induced resistance to clindamycin and nine (29%) were resistant to multiple -antibiotics (MDR), among these, six were MRSA. No MRSA isolates presented the PVL genes. Four MRSA were grouped into three clones and three isolates were not typable by pulsed field gel electrophoresis. MRSA isolates showed, by multilocus sequence typing, sequence types ST1, ST5, ST72 and ST4304 (new ST) and S. aureus protein A (spa type) t127, t568 and t2703. These data suggest that MFC may constitute a risk to the consumer because of its potential for staphylococcal food poisoning; however it might, also, become one of MRSA and MDR strains disseminator, including clones usually found in the hospital environment. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Repurposing the Nonsteroidal Anti-inflammatory Drug Diflunisal as an Osteoprotective, Antivirulence Therapy for Staphylococcus aureus Osteomyelitis.

    Science.gov (United States)

    Hendrix, Andrew S; Spoonmore, Thomas J; Wilde, Aimee D; Putnam, Nicole E; Hammer, Neal D; Snyder, Daniel J; Guelcher, Scott A; Skaar, Eric P; Cassat, James E

    2016-09-01

    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. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  11. A compound magnetic field generating system for targeted killing of Staphylococcus aureus by magnetotactic bacteria in a microfluidic chip

    Science.gov (United States)

    Chen, Linjie; Chen, Changyou; Wang, Pingping; Chen, Chuanfang; Wu, Long-Fei; Song, Tao

    2017-04-01

    A compound magnetic field generating system was built to kill Staphylococcus aureus (S. aureus) by magnetotactic bacteria (MTB) in a microfluidic chip in this paper. The system was consisted of coil pairs, a switch circuit, a control program and controllable electrical sources. It could produce a guiding magnetic field (gMF) of ±1 mT along arbitrary direction in the horizontal plane, a rotating magnetic field (rMF) and a swing magnetic field (sMF, 2 Hz, 10 mT) by controlling the currents. The gMF was used to guide MTB swimming to the S. aureus pool in the microfluidic chip, and then the rMF enhanced the mixture of S. aureus and MTB cells, therefore beneficial to the attachments of them. Finally, the sMF was used to induce the death of S. aureus via MTB. The results showed that MTB could be navigated by the gMF and that 47.1% of S. aureus were killed when exposed to the sMF. It provides a new solution for the targeted treatment of infected diseases and even cancers.

  12. Mastite com lesões sistêmicas por Staphylococus aureus subesp. aureus em coelhos Mastitis with systemic lesions due to Staphylococus aureus subesp. aureus in rabbits

    Directory of Open Access Journals (Sweden)

    Sandra Davi Traverso

    2003-04-01

    Full Text Available Em uma criação composta por 1800 coelhos, 33% das matrizes apresentaram mastite e lesões cutâneas crostosas e purulentas. Estes animais apresentavam-se entre 10 a- 12 meses de idade e em segunda parição. Quinze coelhos afetados foram sacrificados e necropsiados. Na necropsia, além das lesões cutâneas haviam microabscessos em diversos órgãos. Das amostras coletadas isolou-se Staphylococcus aureus subesp. aureus. S. aureus subesp. aureus também foi isolado de "swab" nasal coletado do tratador encarregado de fazer o diagnóstico de gestação nas coelhas. Histologicamente, havia formação de múltiplos abscessos, presença de bactérias gram positivas em vasos sangüíneos e linfáticos, além de êmbolos bacterianos nos tecidos. Nas mamas, observou-se tecido glandular normal associado a abscessos multifocais delimitados.At a commercial rabbitry which was composed of 1800 New Zealand White rabbits, 30% of the does had presented mastitis and purulent cutaneal lesions. The age of the animals ranged from 10 to 12 months and were at the second parturition. At necropsy, microabscesses were observed in several organs. Bacteriological samples collected from affected animals resulted Staphylococcus aureus subesp. aureus.. Additionally, the same agent has been isolated from a nasal swab collected from the person responsible for the pregnancy diagnosis. Histologically, there were multiple abscesses, gram positive bacteria within blood and lymphatic vessels, and bacterial emboli scattered in the tissues. In the mammas, normal glandular tissue associated with multifocal abscesses were observed.

  13. Temporal and stochastic control of Staphylococcus aureus biofilm development.

    Science.gov (United States)

    Moormeier, Derek E; Bose, Jeffrey L; Horswill, Alexander R; Bayles, Kenneth W

    2014-10-14

    Biofilm communities contain distinct microniches that result in metabolic heterogeneity and variability in gene expression. Previously, these niches were visualized within Staphylococcus aureus biofilms by observing differential expression of the cid and lrg operons during tower formation. In the present study, we examined early biofilm development and identified two new stages (designated "multiplication" and "exodus") that were associated with changes in matrix composition and a distinct reorganization of the cells as the biofilm matured. The initial attachment and multiplication stages were shown to be protease sensitive but independent of most cell surface-associated proteins. Interestingly, after 6 h of growth, an exodus of the biofilm population that followed the transition of the biofilm to DNase I sensitivity was demonstrated. Furthermore, disruption of the gene encoding staphylococcal nuclease (nuc) abrogated this exodus event, causing hyperproliferation of the biofilm and disrupting normal tower development. Immediately prior to the exodus event, S. aureus cells carrying a nuc::gfp promoter fusion demonstrated Sae-dependent expression but only in an apparently random subpopulation of cells. In contrast to the existing model for tower development in S. aureus, the results of this study suggest the presence of a Sae-controlled nuclease-mediated exodus of biofilm cells that is required for the development of tower structures. Furthermore, these studies indicate that the differential expression of nuc during biofilm development is subject to stochastic regulatory mechanisms that are independent of the formation of metabolic microniches. Importance: In this study, we provide a novel view of four early stages of biofilm formation by the human pathogen Staphylococcus aureus. We identified an initial nucleoprotein matrix during biofilm development that is DNase I insensitive until a critical point when a nuclease-mediated exodus of the population is induced prior

  14. Expression of Four Methionine Sulfoxide Reductases in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Kuldeep Singh

    2012-01-01

    Full Text Available Staphylococcus aureus possesses three MsrA enzymes (MsrA1, MsrA2, MsrA3 that reduce the S-epimer of methionine sulfoxide (MetO and an MsrB enzyme that reduces R-MetO. The four msr genes are expressed from three different promoters. The msrA1/msrB genes are coexpressed. To determine the expression pattern of msr genes, three independent reporter strains were constructed where msr promoter was cloned in front of a promoterless lacZ and the resulting construct was integrated in the chromosome. Using these strains, it was determined that the msrA1/B expression is significantly higher in S. aureus compared to msrA2 or msrA3. Expression of msrA1/B was highest during stationary phase growth, but the expression of msrA2 and msrA3 was highest during the early to midexponential growth phase. Expression of msrA1/B was induced by oxacillin and the expression of msrA3 was upregulated by salt. Expression of msrA2 remained unchanged under all tested conditions.

  15. Plasmid-determined heavy metal resistances in Staphylococcus aureus

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, A.; Schottel, J.; Silver, S.

    1976-01-01

    Plasmid PI258 of S. aureus has separate genes determining resistance to cadmium and to mercury and the organomercurial phenylmercury acetate. Mercury(ial) resistance is due to the inducible synthesis of a mercury volatilization system. Hg/sup 2 +/ and mercury in phenylmercury acetate is enzymatically reduced to Hg/sup 0/, which is insoluble in water and highly volatile. PI258 differs from most enteric or pseudomonad plasmids which have been studied which determine resistance only to inorganic Hg/sup 2 +/. Cadmium resistance has been found only with staph plasmids. Cadmium resistance is constitutive and is associated with a lower accumulation of cadmium by the plasmid-bearing resistant cells. Cadmium accumulation by sensitive cells is energy-dependent and has those characteristics usually associated with a transmembrane active transport system. There is a specific interrelationship between cadmium accumulation and manganese accumulation and retention. Cd/sup 2 +/ competitively inhibits the uptake of Mn/sup 2 +/ and accelerates the loss of intracellular Mn/sup 2 +/ by the sensitive but has no effect on the resistant S. aureus. Under similar conditions there is no differential effect of Cd/sup 2 +/ on Mg/sup 2 +/, Zn/sup 2 +/, Co/sup 2 +/ or Rb/sup +/ accumulation or exchange between the sensitive and the resistant strains.

  16. Glucose Augments Killing Efficiency of Daptomycin Challenged Staphylococcus aureus Persisters.

    Directory of Open Access Journals (Sweden)

    Marcel Prax

    Full Text Available Treatment of Staphylococcus aureus in stationary growth phase with high doses of the antibiotic daptomycin (DAP eradicates the vast majority of the culture and leaves persister cells behind. Despite resting in a drug-tolerant and dormant state, persister cells exhibit metabolic activity which might be exploited for their elimination. We here report that the addition of glucose to S. aureus persisters treated with DAP increased killing by up to five-fold within one hour. This glucose-DAP effect also occurred with strains less sensitive to the drug. The underlying mechanism is independent of the proton motive force and was not observed with non-metabolizable 2-deoxy-glucose. Our results are consistent with two hypotheses on the glucose-DAP interplay. The first is based upon glucose-induced carbohydrate transport proteins that may influence DAP and the second suggests that glucose may trigger the release or activity of cell-lytic proteins to augment DAP's mode of action.

  17. HPLC-MS/MS targeted metabolic profiling reveals distinct metabolic profiles from Staphylococcus aureus small-colony variants.

    Science.gov (United States)

    Wang, Chen; Zhu, Jiangjiang

    2017-08-15

    Staphylococcus aureus is a world-wide health threat due to its prevalence and possible resistance to antibiotic treatment. A variety reasons can contribute to S. aureus antibiotic resistance and one group of phenotypes that may be discovered from S. aureus is named small-colony variants (SCVs). This study focused on applying a HPLC-MS/MS based targeted metabolic profiling approach to detect a set of metabolites that are dysregulated during S. aureus SCVs formation. Over one hundred and eighty metabolites were confidently detected and their difference between S. aureus SCVs and wild type control groups was compared via univariate and multivariate statistical analyses. Twenty metabolites, including 3',5'-cyclic AMP, tyrosine and adenine were identified as SCV specific metabolic features in comparison to the control group. Metabolic profile differences between individually isolated SCV were also observed and compared. Principal component analyses demonstrated clear metabolic profile differentiation between wild type control to SCVs. Metabolic pathway impact analysis also identified multiple metabolic pathways, including alanine, aspartate and glutamate metabolism, glycine, serine and threonine metabolism, that were significantly impacted during SCV formation. To the best of our knowledge, our study is the very first report to detect a large set of altered metabolites induced by S. aureus SCV formation. We believe our method can be used in combination with genomic, transcriptomic and proteomic approaches to achieve a better understanding of the unique physiological and metabolic changes during S. aureus SCV formation, and to assist the potential future development of targeted treatment for S. aureus SCV infections. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. The Inflammasome and the Epidermal Growth Factor Receptor (EGFR Are Involved in the Staphylococcus aureus-Mediated Induction of IL-1alpha and IL-1beta in Human Keratinocytes.

    Directory of Open Access Journals (Sweden)

    Maren Simanski

    Full Text Available Staphylococcus (S. aureus is an important pathogen causing various infections including those of the skin. Keratinocytes are able to sense invading S. aureus and to initiate a fast defense reaction by the rapid release of innate defense mediators such as antimicrobial peptides and cytokines. There is increasing evidence that the cytokines IL-1alpha and IL-1beta, which both signal through the IL-1 receptor, play an important role in cutaneous defense against S. aureus. The aim of this study was to gain more insight into the underlying mechanisms leading to the S. aureus-induced IL-1alpha and IL-1beta expression in keratinocytes. Infection of human primary keratinocytes with S. aureus led to the induction of gene expression and protein secretion of IL-1alpha and IL-1beta. Full S. aureus-induced IL-1 protein release required the inflammasome components caspase-1 and ASC (apoptosis-associated speck-like protein containing a CARD whereas gene induction of IL-1alpha and IL-beta by S. aureus was not dependent on caspase-1 and ASC. Since patients receiving anti-cancer therapy by inhibition of the epidermal growth factor receptor (EGFR often suffer from skin infections caused by S. aureus we additionally evaluated whether the EGFR pathway may be involved in the IL-1alpha and IL-1beta induction by S. aureus. Inactivation of the EGFR with a blocking antibody decreased the S. aureus-mediated IL-1alpha and IL-1beta induction in primary keratinocytes. Moreover, the use of siRNA experiments revealed that ADAM17 (A Disintegrin and A Metalloprotease 17, a metalloproteinase known to mediate the shedding and release of EGFR ligands, was required for full induction of IL-1alpha and IL-1beta in keratinocytes infected with S. aureus. A failure of keratinocytes to adequately upregulate IL-1alpha and IL-1beta may promote S. aureus skin infections.

  19. Antibiotic resistant Staphylococcus aureus in Abia State of Nigeria ...

    African Journals Online (AJOL)

    A total of 70 ear and nasal swab samples collected from 35 persons, 16-hospital population and 19 non-hospital population was examined for presence of Staphylococcus aureus. Eighty percent of the population studied were found to be carriers of S. aureus. Of the 28 positive cases, 35.7% were carriers of S. aureus. in ...

  20. Nasal carriage of methicillin-resistant Staphylococcus aureus by ...

    African Journals Online (AJOL)

    Strains of Staphylococcus aureus were isolated from the anterior nares of healthy pupils and their antibiotic susceptibility patterns were determined. 116 isolates of Staphylococcus aureus (100%) were biochemically characterized as coagulase positive S. aureus. Susceptibility profile of the isolates revealed that 15(14.85%) ...

  1. 21 CFR 866.3700 - Staphylococcus aureus serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Staphylococcus aureus serological reagents. 866... Staphylococcus aureus serological reagents. (a) Identification. Staphylococcus aureus serological reagents are... diagnosis of disease caused by this bacterium belonging to the genus Staphylococcus and provides...

  2. 9 CFR 113.115 - Staphylococcus Aureus Bacterin-Toxoid.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Staphylococcus Aureus Bacterin-Toxoid... REQUIREMENTS Inactivated Bacterial Products § 113.115 Staphylococcus Aureus Bacterin-Toxoid. Staphylococcus... Staphylococcus aureus which has been inactivated and is nontoxic. Each serial of biological product containing...

  3. Immunological role of nasal staphylococcus aureus carriage in ...

    African Journals Online (AJOL)

    raoul

    2008-10-30

    Oct 30, 2008 ... Nasal carriage of staphylococcus aureus (S. aureus) exerts immunomodulatory effects in patients with atopic dermatitis and it may contribute to airway inflammation and allergic response in patients with allergic rhinitis. We investigated the frequency of nasal S. aureus carriage in patients with perennial ...

  4. The sensitivity status of community-acquired Staphylococcus aureus ...

    African Journals Online (AJOL)

    Community acquired Staphylococcus aureus was isolated from various infectious sites in two private laboratories in Kano-city, Nigeria. A total of 247 (11%) Staphylococcu aureus isolates were recovered from all infectious sites except cerebro-spinal fluid. The least Staphylococcus aureus isolates were found in urine ...

  5. Antibiotic resistance of Staphylococcus aureus isolated from fresh ...

    African Journals Online (AJOL)

    Three Hundred and Sixty fresh cow milk samples were collected from settled Fulani herds in Kaduna State and examined for S. aureus and their antibiotic resistance. Fifty five samples (15.3%) were positive for S. aureus. The occurrence of S. aureus was statistically significant (P<0.005) based on locations. Statistical ...

  6. Four-component Staphylococcus aureus vaccine 4C-staph enhances Fcγ receptor expression in neutrophils and monocytes and mitigates S. aureus infection in neutropenic mice.

    Science.gov (United States)

    Torre, Antonina; Bacconi, Marta; Sammicheli, Chiara; Galletti, Bruno; Laera, Donatello; Fontana, Maria Rita; Grandi, Guido; De Gregorio, Ennio; Bagnoli, Fabio; Nuti, Sandra; Bertholet, Sylvie; Bensi, Giuliano

    2015-08-01

    Staphylococcus aureus is a human bacterial pathogen causing a variety of diseases. The occurrence of multidrug-resistant strains of Staphylococcus aureus underlines the need for a vaccine. Defining immune correlates of protection may support the design of an effective vaccine. We used a murine Staphylococcus aureus infection model, in which bacteria were inoculated in an air pouch generated on the back of the animal. Analysis of the air-pouch content in mice immunized or not with an adjuvanted multiantigen vaccine formulation, four-component S. aureus vaccine (4C-Staph), prior to infection allowed us to measure bacteria, cytokines, and 4C-Staph-specific antibodies and to analyze host immune cells recruited to the infection site. Immunization with 4C-Staph resulted in accumulation of antigen-specific antibodies in the pouch and mitigated the infection. Neutrophils were the most abundant cells in the pouch, and they showed the upregulation of Fcγ receptor (FcγR) following immunization with 4C-Staph. Reduction of the infection was also obtained in mice immunized with 4C-Staph and depleted of neutrophils; these mice showed an increase in monocytes and macrophages. Upregulation of the FcγR and the presence of antigen-specific antibodies induced by immunization with 4C-Staph may contribute to increase bacterial opsonophagocytosis. Protection in neutropenic mice indicated that an effective vaccine could activate alternative protection mechanisms compensating for neutropenia, a condition often occurring in S. aureus-infected patients. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. Staphylococcus aureus entrance into the dairy chain: Tracking S. aureus from dairy cow to cheese

    Directory of Open Access Journals (Sweden)

    Judith Kümmel

    2016-10-01

    Full Text Available Staphylococcus aureus is one of the most important contagious mastitis pathogens in dairy cattle. Due to its zoonotic potential, control of S. aureus is not only of great economic importance in the dairy industry but also a significant public health concern. The aim of this study was to decipher the potential of bovine udder associated S. aureus as reservoir for S. aureus contamination in dairy production and processing. From 18 farms, delivering their milk to an alpine dairy plant for the production of smeared semi-hard and hard cheese. 1176 quarter milk (QM samples of all cows in lactation (n = 294 and representative samples form bulk tank milk (BTM of all farms were surveyed for coagulase positive (CPS and coagulase negative Staphylococci (CNS. Furthermore, samples from different steps of the cheese manufacturing process were tested for CPS and CNS. As revealed by chemometric-assisted FTIR spectroscopy and molecular subtyping (spa typing and multi locus sequence typing, dairy cattle represent indeed an important, yet underreported, entrance point of S. aureus into the dairy chain. Our data clearly show that certain S. aureus subtypes are present in primary production as well as in the cheese processing at the dairy plant. However, although a considerable diversity of S. aureus subtypes was observed in QM and BTM at the farms, only certain S. aureus subtypes were able to enter and persist in the cheese manufacturing at the dairy plant and could be isolated from cheese until day fourteen of ripening. Farm strains belonging to the FTIR cluster B1 and B3, which show genetic characteristics (t2953, ST8, enterotoxin profile: sea/sed/sej of the recently described S. aureus genotype B, most successfully contaminated the cheese production at the dairy plant. Thus our study fosters the hypothesis that genotype B S. aureus represent a specific challenge in control of S. aureus in the dairy chain that requires effective clearance strategies and hygienic

  8. Staphylococcus aureus Entrance into the Dairy Chain: Tracking S. aureus from Dairy Cow to Cheese

    Science.gov (United States)

    Kümmel, Judith; Stessl, Beatrix; Gonano, Monika; Walcher, Georg; Bereuter, Othmar; Fricker, Martina; Grunert, Tom; Wagner, Martin; Ehling-Schulz, Monika

    2016-01-01

    Staphylococcus aureus is one of the most important contagious mastitis pathogens in dairy cattle. Due to its zoonotic potential, control of S. aureus is not only of great economic importance in the dairy industry but also a significant public health concern. The aim of this study was to decipher the potential of bovine udder associated S. aureus as reservoir for S. aureus contamination in dairy production and processing. From 18 farms, delivering their milk to an alpine dairy plant for the production of smeared semi-hard and hard cheese. one thousand hundred seventy six one thousand hundred seventy six quarter milk (QM) samples of all cows in lactation (n = 294) and representative samples form bulk tank milk (BTM) of all farms were surveyed for coagulase positive (CPS) and coagulase negative Staphylococci (CNS). Furthermore, samples from different steps of the cheese manufacturing process were tested for CPS and CNS. As revealed by chemometric-assisted FTIR spectroscopy and molecular subtyping (spa typing and multi locus sequence typing), dairy cattle represent indeed an important, yet underreported, entrance point of S. aureus into the dairy chain. Our data clearly show that certain S. aureus subtypes are present in primary production as well as in the cheese processing at the dairy plant. However, although a considerable diversity of S. aureus subtypes was observed in QM and BTM at the farms, only certain S. aureus subtypes were able to enter and persist in the cheese manufacturing at the dairy plant and could be isolated from cheese until day 14 of ripening. Farm strains belonging to the FTIR cluster B1 and B3, which show genetic characteristics (t2953, ST8, enterotoxin profile: sea/sed/sej) of the recently described S. aureus genotype B, most successfully contaminated the cheese production at the dairy plant. Thus, our study fosters the hypothesis that genotype B S. aureus represent a specific challenge in control of S. aureus in the dairy chain that requires

  9. Antibiograms of Staphylococcus Aureus and Pseudomonas ...

    African Journals Online (AJOL)

    While there was no bacterial growth after 48hrs incubation recorded for group one, only 5(13.9%) samples yielded growth of Staphylococcus aureus for group two with 31(86.1%) yielding no bacterial growth. All group three samples yielded profuse growth of which 11(36.7%) yielded Pseudomonas aeruginosa and ...

  10. Staphylococcus aureus resistente a la meticilina (SARM)

    Centers for Disease Control (CDC) Podcasts

    2007-10-22

    Datos importantes sobre las infecciones por SARM en Estados Unidos, en las escuelas y los entornos médicos. (Title: Methicillin-resistant Staphylococcus aureus (MRSA)Created: 10/2007).  Created: 10/22/2007 by National Center for Preparedness, Detection, and Control of Infectious Diseases.   Date Released: 11/9/2007.

  11. Human Staphylococcus aureus lineages among Zoological Park ...

    African Journals Online (AJOL)

    Clones were defined by Multilocus Sequence Typing (MLST), spa type and Pulsed-Field Gel Electrophoresis (PFGE). Seven S. aureus isolates were recovered from four animals and one from an employee. All were mecA, mecC and tst–negative, whereas, one carried the PVL genes and was isolated from an infected ...

  12. Profiling the surfacome of Staphylococcus aureus

    NARCIS (Netherlands)

    Dreisbach, Annette; Hempel, Kristina; Buist, Girbe; Hecker, Michael; Becher, Doerte; van Dijl, Jan Maarten

    Staphylococcus aureus is a widespread opportunistic pathogen that can cause a wide variety of life-threatening diseases. Especially for the colonization of human tissues and the development of invasiveness, surface-exposed proteins are of major importance. In the present studies, we optimized a

  13. Resistance patterns of Staphylococcus aureus and Pseudomonas ...

    African Journals Online (AJOL)

    Two hundred (200) strains of S. aureus and P. aeruginosa were isolated from clinical samples collected from patients in Murtala Muhammad Specialist Hospital and Infectious Diseases Hospital, Kano. The confirmed isolates were tested for resistance to quinolones by the agar disk diffusion susceptibility test and the agar ...

  14. Methicillin-resistant Staphylococcus aureus transmission

    DEFF Research Database (Denmark)

    Andersen, Leif Percival; Nielsen, Xiaohui

    2015-01-01

    INTRODUCTION: Even though methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infections, it may often be difficult to evaluate the exact route of transmission. METHODS: In this study, we describe four cases of nosocomial transmission of MRSA in a hospital with a low...

  15. Staphylococcus aureus spa type t437

    DEFF Research Database (Denmark)

    Glasner, C; Pluister, G; Westh, H

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) belonging to the multilocus sequence type clonal complex 59 (MLST CC59) is the predominant community-associated MRSA clone in Asia. This clone, which is primarily linked with the spa type t437, has so far only been reported in low numbers among...

  16. Antibiotic susceptibility of Staphylococcus aureus in suppurative ...

    African Journals Online (AJOL)

    Background: Staphylococcus aureus, a mainly acquired hospital infection is responsible for many suppurative lesions and has demonstrated the ability of developing resistance to many antimicrobial agents leading to life threatening infections and long hospital stay. Objective: To determined the prevalence and antibiotic ...

  17. Polyclonal antibodies production against Staphylococcus aureus ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-02-01

    Feb 1, 2010 ... The main aim of this project is to produce polyclonal antibodies directed against the Staphylococcus aureus protein A and their use to appreciate bacteriological analysis of milk quality. In this context, an immunization produce was set up to test and detect in a batch of animals the convenient responder to.

  18. Meticillineresistente Staphylococcus aureus (MRSA) in de gemeenschap

    NARCIS (Netherlands)

    Vonk, A. G.; Vandenbroucke-Grauls, C. M. J. E.

    2007-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) infections have been confined to healthcare centres for decades. However, MRSA infections are increasingly seen in young healthy individuals with no exposure to healthcare centres. These community-acquired MRSA (CA-MRSA) strains differ from

  19. Staphylococcus aureus infections; Lead by the nose

    NARCIS (Netherlands)

    H.F.L. Wertheim (Heiman)

    2005-01-01

    textabstractAn overview and the latest insights regarding S. aureus nasal carriage, associated risks of developing infections and possible preventive measures, will be given in Chapter 2. Since mupirocin efficacy studies in preventing nosocomial infections have only been performed in surgical and

  20. Microbial population of Staphyloccous aureus from inanimate ...

    African Journals Online (AJOL)

    High frequency of S. aureus was observed in toilet seat with perecentage distribution of 78%, followed by floor with percentage distribution of 70% and locker with percentage distribution of 65% and the lowest frequency occurence was observed in switch with percentage distribution of 30%. Frequency occurrence of S.

  1. Aureolib - a proteome signature library: towards an understanding of staphylococcus aureus pathophysiology.

    Directory of Open Access Journals (Sweden)

    Stephan Fuchs

    Full Text Available Gel-based proteomics is a powerful approach to study the physiology of Staphylococcus aureus under various growth restricting conditions. We analyzed 679 protein spots from a reference 2-dimensional gel of cytosolic proteins of S. aureus COL by mass spectrometry resulting in 521 different proteins. 4,692 time dependent protein synthesis profiles were generated by exposing S. aureus to nine infection-related stress and starvation stimuli (H2O2, diamide, paraquat, NO, fermentation, nitrate respiration, heat shock, puromycin, mupirocin. These expression profiles are stored in an online resource called Aureolib (http://www.aureolib.de. Moreover, information on target genes of 75 regulators and regulatory elements were included in the database. Cross-comparisons of this extensive data collection of protein synthesis profiles using the tools implemented in Aureolib lead to the identification of stress and starvation specific marker proteins. Altogether, 226 protein synthesis profiles showed induction ratios of 2.5-fold or higher under at least one of the tested conditions with 157 protein synthesis profiles specifically induced in response to a single stimulus. The respective proteins might serve as marker proteins for the corresponding stimulus. By contrast, proteins whose synthesis was increased or repressed in response to more than four stimuli are rather exceptional. The only protein that was induced by six stimuli is the universal stress protein SACOL1759. Most strikingly, cluster analyses of synthesis profiles of proteins differentially synthesized under at least one condition revealed only in rare cases a grouping that correlated with known regulon structures. The most prominent examples are the GapR, Rex, and CtsR regulon. In contrast, protein synthesis profiles of proteins belonging to the CodY and σ(B regulon are widely distributed. In summary, Aureolib is by far the most comprehensive protein expression database for S. aureus and provides

  2. Host response signature to Staphylococcus aureus alpha-hemolysin implicates pulmonary Th17 response.

    Science.gov (United States)

    Frank, Karen M; Zhou, Tong; Moreno-Vinasco, Liliana; Hollett, Brian; Garcia, Joe G N; Bubeck Wardenburg, Juliane

    2012-09-01

    Staphylococcus aureus pneumonia causes significant morbidity and mortality. Alpha-hemolysin (Hla), a pore-forming cytotoxin of S. aureus, has been identified through animal models of pneumonia as a critical virulence factor that induces lung injury. In spite of considerable molecular knowledge of how this cytotoxin injures the host, the precise host response to Hla in the context of infection remains poorly understood. We employed whole-genome expression profiling of infected lungs to define the host response to wild-type S. aureus compared with the response to an Hla-deficient isogenic mutant in experimental pneumonia. These data provide a complete expression profile at 4 and at 24 h postinfection, revealing a unique response to the toxin-expressing strain. Gene ontogeny analysis revealed significant differences in the extracellular matrix and cardiomyopathy pathways, both of which govern cellular interactions in the tissue microenvironment. Evaluation of individual transcript responses to Hla-secreting staphylococci was notable for upregulation of host cytokine and chemokine genes, including the p19 subunit of interleukin-23. Consistent with this observation, the cellular immune response to infection was characterized by a prominent Th17 response to the wild-type pathogen. These findings define specific host mRNA responses to Hla-producing S. aureus, coupling the pulmonary Th17 response to the secretion of this cytotoxin. Expression profiling to define the host response to a single virulence factor proved to be a valuable tool in identifying pathways for further investigation in S. aureus pneumonia. This approach may be broadly applicable to the study of bacterial toxins, defining host pathways that can be targeted to mitigate toxin-induced disease.

  3. Prevalence of Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA) in the oral cavity.

    Science.gov (United States)

    Koukos, Georgios; Sakellari, Dimitra; Arsenakis, Minas; Tsalikis, Lazaros; Slini, Theodora; Konstantinidis, Antonios

    2015-09-01

    To assess the prevalence of Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA) in plaque and tongue samples from systemically healthy subjects with periodontal health, gingivitis or chronic periodontitis. After screening 720 potentially eligible subjects, 154 systemically healthy participants were ultimately enrolled in the current study. Subgingival samples were taken from the first molars and the tongue and analyzed for the presence of S. aureus and MRSA by polymerase chain reaction (PCR), using primers and conditions previously described in the literature. In addition, samples were taken from deep periodontal pockets of chronic periodontitis patients. Statistical analysis was performed by applying non-parametric tests (Kruskal-Wallis for clinical parameters, and z-test with Bonferroni corrections for distributions of assessed parameters). All comparisons were set at the 0.05 significance level. S. aureus was detected in 18% of all participants and in 10% of the samples tested. No significant differences were found in its distribution among the three investigated groups (z-test for proportions with Bonferroni corrections, p>0.05). The mecA gene was not present in any of the S. aureus found. S. aureus can be found in the oral environment regardless of the periodontal conditions and therefore should be considered as a member of the transient flora not participating in periodontal pathology. Subgingival sites and tongue surfaces seem to be an unusual habitat of MRSA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Transcriptomic and metabolic responses of Staphylococcus aureus exposed to supra-physiological temperatures

    Directory of Open Access Journals (Sweden)

    Proctor Richard A

    2009-04-01

    Full Text Available Abstract Background Previous evaluation by different molecular and physiological assays of Staphylococcus aureus (S. aureus responses to heat shock exposure yielded a still fragmentary view of the mechanisms determining bacterial survival or death at supra-physiological temperatures. This study analyzed diverse facets of S. aureus heat-shock adjustment by recording global transcriptomic and metabolic responses of bacterial cultures shifted for 10 min from 37°C to a sub-lethal (43°C or eventually lethal (48°C temperature. A relevant metabolic model of the combined action of specific stress response mechanisms with more general, energy-regulating metabolic pathways in heat-shocked S. aureus is presented. Results While S. aureus cultures shifted to 43°C or left at 37°C showed marginal differences in growth and survival rates, bacterial cultures exposed to 48°C showed a rapid growth arrest followed by a subsequent decline in viable counts. The most substantial heat shock-induced changes at both 43°C and 48°C occurred in transcript levels of HrcA- and CtsR-regulated genes, encoding classical chaperones DnaK and GroESL, and some Hsp100/Clp ATPases components, respectively. Other metabolic pathways up-regulated by S. aureus exposure at 48°C included genes encoding several enzymes coping with oxidative stress, and DNA damage, or/and impaired osmotic balance. Some major components of the pentose phosphate cycle and gluconeogenesis were also up-regulated, which reflected depletion of free glucose by bacterial cultures grown in Mueller-Hinton broth prior to heat shock. In contrast, most purine- and pyrimidine-synthesis pathway components and amino acyl-tRNA synthetases were down-regulated at 48°C, as well as arginine deiminase and major fermentative pathway components, such as alcohol, lactate and formate dehydrogenases. Despite the heat-induced, increased requirements for ATP-dependent macromolecular repair mechanisms combined with declining

  5. Intracellular activity of clinical concentrations of phenothiazines including thioridiazine against phagocytosed Staphylococcus aureus.

    Science.gov (United States)

    Ordway, Diane; Viveiros, Miguel; Leandro, Clara; Arroz, Maria Jorge; Amaral, Leonard

    2002-07-01

    The effect of thioridazine (TZ) was studied on the killing activity of human peripheral blood monocyte derived macrophages (HPBMDM) and of human macrophage cell line THP-1 at extracellular concentrations below those achievable clinically. These macrophages have nominal killing activity against bacteria and therefore, would not influence any activity that the compounds may have against intracellular localised Staphylococcus aureus. The results indicated that whereas TZ has an in vitro minimum inhibitory concentration (MIC) against the strains of S. aureus of 18, 0.1 mg/l of TZ in the medium completely inhibits the growth of S. aureus that has been phagocytosed by macrophages. The latter concentration was non-toxic to macrophages, did not cause cellular expression of activation marker CD69 nor induction of CD3+ T cell production of IFN-gamma, but blocked cellular proliferation and down-regulated the production of T cell-derived cytokines (IFN-gamma, IL-5). These results suggest that TZ induces intracellular bactericidal activities independent of the capacity to generate Type 1 responses against S. aureus.

  6. Environment-Mediated Accumulation of Diacyl Lipoproteins over Their Triacyl Counterparts in Staphylococcus aureus

    Science.gov (United States)

    Kurokawa, Kenji; Kim, Min-Su; Ichikawa, Rie; Ryu, Kyoung-Hwa; Dohmae, Naoshi

    2012-01-01

    Bacterial lipoproteins are believed to exist in only one specific lipid-modified structure, such as the diacyl form or the triacyl form, in each bacterium. In the case of Staphylococcus aureus, recent extensive matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry analysis revealed that S. aureus lipoproteins exist in the α-aminoacylated triacyl form. Here, we discovered conditions that induce the accumulation of diacyl lipoproteins that lack α-aminoacylation in S. aureus. The accumulation of diacyl lipoproteins required a combination of conditions, including acidic pH and a post-logarithmic-growth phase. High temperatures and high salt concentrations additively accelerated the accumulation of the diacyl lipoprotein form. Following a post-logarithmic-growth phase where S. aureus MW2 cells were grown at pH 6, SitC lipoprotein was found almost exclusively in its diacyl structure rather than in its triacyl structure. This is the first report showing that the environment mediates lipid-modified structural alterations of bacterial lipoproteins. PMID:22467779

  7. Staphylococcus aureus Infection Reduces Nutrition Uptake and Nucleotide Biosynthesis in a Human Airway Epithelial Cell Line

    Directory of Open Access Journals (Sweden)

    Philipp Gierok

    2016-11-01

    Full Text Available The Gram positive opportunistic human pathogen Staphylococcus aureus induces a variety of diseases including pneumonia. S. aureus is the second most isolated pathogen in cystic fibrosis patients and accounts for a large proportion of nosocomial pneumonia. Inside the lung, the human airway epithelium is the first line in defence with regard to microbial recognition and clearance as well as regulation of the immune response. The metabolic host response is, however, yet unknown. To address the question of whether the infection alters the metabolome and metabolic activity of airway epithelial cells, we used a metabolomics approach. The nutrition uptake by the human airway epithelial cell line A549 was monitored over time by proton magnetic resonance spectroscopy (1H-NMR and the intracellular metabolic fingerprints were investigated by gas chromatography and high performance liquid chromatography (GC-MS and (HPLC-MS. To test the metabolic activity of the host cells, glutamine analogues and labelled precursors were applied after the infection. We found that A549 cells restrict uptake of essential nutrients from the medium after S. aureus infection. Moreover, the infection led to a shutdown of the purine and pyrimidine synthesis in the A549 host cell, whereas other metabolic routes such as the hexosamine biosynthesis pathway remained active. In summary, our data show that the infection with S. aureus negatively affects growth, alters the metabolic composition and specifically impacts the de novo nucleotide biosynthesis in this human airway epithelial cell model.

  8. Induction of type I interferon signaling determines the relative pathogenicity of Staphylococcus aureus strains.

    Directory of Open Access Journals (Sweden)

    Dane Parker

    2014-02-01

    Full Text Available The tremendous success of S. aureus as a human pathogen has been explained primarily by its array of virulence factors that enable the organism to evade host immunity. Perhaps equally important, but less well understood, is the importance of the intensity of the host response in determining the extent of pathology induced by S. aureus infection, particularly in the pathogenesis of pneumonia. We compared the pathogenesis of infection caused by two phylogenetically and epidemiologically distinct strains of S. aureus whose behavior in humans has been well characterized. Induction of the type I IFN cascade by strain 502A, due to a NOD2-IRF5 pathway, was the major factor in causing severe pneumonia and death in a murine model of pneumonia and was associated with autolysis and release of peptidogylcan. In contrast to USA300, 502A was readily eliminated from epithelial surfaces in vitro. Nonetheless, 502A caused significantly increased tissue damage due to the organisms that were able to invade systemically and trigger type I IFN responses, and this was ameliorated in Ifnar⁻/⁻ mice. The success of USA300 to cause invasive infection appears to depend upon its resistance to eradication from epithelial surfaces, but not production of specific toxins. Our studies illustrate the important and highly variable role of type I IFN signaling within a species and suggest that targeted immunomodulation of specific innate immune signaling cascades may be useful to prevent the excessive morbidity associated with S. aureus pneumonia.

  9. Bacterial Cytological Profiling (BCP as a Rapid and Accurate Antimicrobial Susceptibility Testing Method for Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    D.T. Quach

    2016-02-01

    Full Text Available Successful treatment of bacterial infections requires the timely administration of appropriate antimicrobial therapy. The failure to initiate the correct therapy in a timely fashion results in poor clinical outcomes, longer hospital stays, and higher medical costs. Current approaches to antibiotic susceptibility testing of cultured pathogens have key limitations ranging from long run times to dependence on prior knowledge of genetic mechanisms of resistance. We have developed a rapid antimicrobial susceptibility assay for Staphylococcus aureus based on bacterial cytological profiling (BCP, which uses quantitative fluorescence microscopy to measure antibiotic induced changes in cellular architecture. BCP discriminated between methicillin-susceptible (MSSA and -resistant (MRSA clinical isolates of S. aureus (n = 71 within 1–2 h with 100% accuracy. Similarly, BCP correctly distinguished daptomycin susceptible (DS from daptomycin non-susceptible (DNS S. aureus strains (n = 20 within 30 min. Among MRSA isolates, BCP further identified two classes of strains that differ in their susceptibility to specific combinations of beta-lactam antibiotics. BCP provides a rapid and flexible alternative to gene-based susceptibility testing methods for S. aureus, and should be readily adaptable to different antibiotics and bacterial species as new mechanisms of resistance or multidrug-resistant pathogens evolve and appear in mainstream clinical practice.

  10. Inhibition of endothelial interleukin-8 production and neutrophil transmigration by Staphylococcus aureus beta-hemolysin.

    Science.gov (United States)

    Tajima, Akiko; Iwase, Tadayuki; Shinji, Hitomi; Seki, Keiko; Mizunoe, Yoshimitsu

    2009-01-01

    Neutrophils play a crucial role in the host response to infection with Staphylococcus aureus, which is a major human pathogen capable of causing life-threatening disease. Interleukin-8 (IL-8) is a potent chemoattractant and activator of neutrophils. We previously reported that S. aureus secretes a factor that suppresses IL-8 production by human endothelial cells. Here we isolated an inhibitor of IL-8 production from the supernatant and identified it as staphylococcal beta-hemolysin. Beta-hemolysin reduced IL-8 production without cytotoxicity to endothelial cells. Pretreatment with beta-hemolysin decreased the expression of both IL-8 mRNA and protein induced by tumor necrosis factor alpha (TNF-alpha). Migration of neutrophils across TNF-alpha-activated endothelium was also inhibited by beta-hemolysin. In contrast, beta-hemolysin had no effect on intercellular adhesive molecule 1 expression in activated endothelial cells. These results showed that beta-hemolysin produced by S. aureus interferes with inflammatory signaling in endothelial cells and may help S. aureus evade the host immune response.

  11. Galectin-3 Is a Target for Proteases Involved in the Virulence of Staphylococcus aureus.

    Science.gov (United States)

    Elmwall, Jonas; Kwiecinski, Jakub; Na, Manli; Ali, Abukar Ahmed; Osla, Veronica; Shaw, Lindsey N; Wang, Wanzhong; Sävman, Karin; Josefsson, Elisabet; Bylund, Johan; Jin, Tao; Welin, Amanda; Karlsson, Anna

    2017-07-01

    Staphylococcus aureus is a major cause of skin and soft tissue infection. The bacterium expresses four major proteases that are emerging as virulence factors: aureolysin (Aur), V8 protease (SspA), staphopain A (ScpA), and staphopain B (SspB). We hypothesized that human galectin-3, a β-galactoside-binding lectin involved in immune regulation and antimicrobial defense, is a target for these proteases and that proteolysis of galectin-3 is a novel immune evasion mechanism. Indeed, supernatants from laboratory strains and clinical isolates of S. aureus caused galectin-3 degradation. Similar proteolytic capacities were found in Staphylococcus epidermidis isolates but not in Staphylococcus saprophyticus Galectin-3-induced activation of the neutrophil NADPH oxidase was abrogated by bacterium-derived proteolysis of galectin-3, and SspB was identified as the major protease responsible. The impact of galectin-3 and protease expression on S. aureus virulence was studied in a murine skin infection model. In galectin-3+/+ mice, SspB-expressing S. aureus caused larger lesions and resulted in higher bacterial loads than protease-lacking bacteria. No such difference in bacterial load or lesion size was detected in galectin-3-/- mice, which overall showed smaller lesion sizes than the galectin-3+/+ animals. In conclusion, the staphylococcal protease SspB inactivates galectin-3, abrogating its stimulation of oxygen radical production in human neutrophils and increasing tissue damage during skin infection. Copyright © 2017 American Society for Microbiology.

  12. Response of methicillin-resistant Staphylococcus aureus to amicoumacin A.

    Directory of Open Access Journals (Sweden)

    Amrita Lama

    Full Text Available Amicoumacin A exhibits strong antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA, hence we sought to uncover its mechanism of action. Genome-wide transcriptome analysis of S. aureus COL in response to amicoumacin A showed alteration in transcription of genes specifying several cellular processes including cell envelope turnover, cross-membrane transport, virulence, metabolism, and general stress response. The most highly induced gene was lrgA, encoding an antiholin-like product, which is induced in cells undergoing a collapse of Δψ. Consistent with the notion that LrgA modulates murein hydrolase activity, COL grown in the presence of amicoumacin A showed reduced autolysis, which was primarily caused by lower hydrolase activity. To gain further insight into the mechanism of action of amicoumacin A, a whole genome comparison of wild-type COL and amicoumacin A-resistant mutants isolated by a serial passage method was carried out. Single point mutations generating codon substitutions were uncovered in ksgA (encoding RNA dimethyltransferase, fusA (elongation factor G, dnaG (primase, lacD (tagatose 1,6-bisphosphate aldolase, and SACOL0611 (a putative glycosyl transferase. The codon substitutions in EF-G that cause amicoumacin A resistance and fusidic acid resistance reside in separate domains and do not bring about cross resistance. Taken together, these results suggest that amicoumacin A might cause perturbation of the cell membrane and lead to energy dissipation. Decreased rates of cellular metabolism including protein synthesis and DNA replication in resistant strains might allow cells to compensate for membrane dysfunction and thus increase cell survivability.

  13. Sub-Inhibitory Concentrations of Rifampicin Strongly Stimulated Biofilm Production inS. aureus.

    Science.gov (United States)

    Lima-E-Silva, Agostinho Alves; Silva-Filho, Renato Geraldo; Fernandes, Henry Marcel Zalona; Saramago, Carmen Soares Meirelles; Viana, Alice Slotfeldt; Souza, Maria José; Nogueira, Eduardo Matos

    2017-01-01

    Staphylococcus aureus is an important pathogen and a frequent cause of infections associated with biofilm production in implantable medical devices. Biofilm production can be induced by sub-inhibitory concentrations (sub-MICs) of certain antibiotics, but few studies have researched this occurrence in S. aureus . In this study, we investigated the effect of sub-MICs of rifampicin and minocycline on biofilm production by five clinical and five non-clinical S. aureus isolates. Microtiter Plate assay and Congo Red Agar Test were used to analyze the biofilm production. The biofilm composition was evaluated by the detachment assay with sodium metaperiodate and proteinase K. Rifampicin sub-MICs induced very high biofilm formation in seven isolates that were non-producers in Tryptic Soy Broth. In one producer isolate, the biofilm formation level was not affected by sub-MICs of this drug. Sub-MICs of minocycline did not induce biofilm production in all isolates tested and in two producer isolates, instead, MIC/2 and MIC/4 inhibited biofilm production. The results of the drugs in combination were similar to those with rifampicin alone. The biofilm matrix was identified as polysaccharide, except for one producer isolate, classified as proteinaceous. Polysaccharide biofilm producer isolates, when grown on Congo Red Agar without sucrose, but with sub-MICs of rifampicin, showed results in agreement with those obtained in Microtiter Plate Test. The high biofilm production induced by sub-MICs of rifampicin has potential clinical relevance, because this is one of the drugs commonly used in the impregnation of catheters. In addition, it is used adjunctively to treat certain S. aureus infections.

  14. Performance of vancomycin and teicoplanin disk diffusion test in isogenic vancomycin non-susceptible Staphylococcus aureus.

    Science.gov (United States)

    Wongthong, Sujintana; Dutchanutouch, Karnjana; Namsaengkang, Viladda; Chanawong, Aroonwadee; Wilailuckana, Chotechana; Lulitanond, Aroonlug

    2015-02-19

    Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) is currently problematic. Although the population analysis profile with area under the curve (PAP-AUC) is the gold standard for detecting hVISA strains, this method is time consuming. This study aimed to induce vancomycin non-susceptible Staphylococcus aureus isolates in methicillin-resistant S. aureus (MRSA) and to determine the performance of the vancomycin and teicoplanin disk diffusion test for screening of induced and natural vancomycin non-susceptible isolates. Vancomycin resistance was induced in vitro in methicillin-resistant S. aureus by serial passage in media with increasing vancomycin concentrations. All test isolates were confirmed for their susceptibility to vancomycin by using a PAP-AUC method. The performance of the vancomycin and teicoplanin disk diffusion test for detecting both induced and natural hVISA/VISA isolates was analyzed using the MedCal program version 10.2.0. The induction test revealed that 42 of 78 MRSA isolates (53.8%) became hVISA and/or VISA. Using 10, 15, 20, 30 µg vancomycin disks and a 30 µg teicoplanin disk, the highest performance (88.9%) for hVISA/VISA detection (71.1%), sensitivity, 100% specificity, 100% positive predictive value, and 75% negative predictive value) was obtained when a 20 µg vancomycin disk was used at 1.0 McFarland inoculum for a 24-hour incubation. The results indicated that using a 20 µg vancomycin disk and bacterial inoculum of 1.0 McFarland is simple to perform and provides a primary result for hVISA/VISA screening within 24 hours.

  15. Staphylokinase Control of Staphylococcus aureus Biofilm Formation and Detachment Through Host Plasminogen Activation.

    Science.gov (United States)

    Kwiecinski, Jakub; Peetermans, Marijke; Liesenborghs, Laurens; Na, Manli; Björnsdottir, Halla; Zhu, Xuefeng; Jacobsson, Gunnar; Johansson, Bengt R; Geoghegan, Joan A; Foster, Timothy J; Josefsson, Elisabet; Bylund, Johan; Verhamme, Peter; Jin, Tao

    2016-01-01

    Staphylococcus aureus biofilms, a leading cause of persistent infections, are highly resistant to immune defenses and antimicrobial therapies. In the present study, we investigated the contribution of fibrin and staphylokinase (Sak) to biofilm formation. In both clinical S. aureus isolates and laboratory strains, high Sak-producing strains formed less biofilm than strains that lacked Sak, suggesting that Sak prevents biofilm formation. In addition, Sak induced detachment of mature biofilms. This effect depended on plasminogen activation by Sak. Host-derived fibrin, the main substrate cleaved by Sak-activated plasminogen, was a major component of biofilm matrix, and dissolution of this fibrin scaffold greatly increased susceptibility of biofilms to antibiotics and neutrophil phagocytosis. Sak also attenuated biofilm-associated catheter infections in mouse models. In conclusion, our results reveal a novel role for Sak-induced plasminogen activation that prevents S. aureus biofilm formation and induces detachment of existing biofilms through proteolytic cleavage of biofilm matrix components. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  16. α-Hemolysin enhances Staphylococcus aureus internalization and survival within mast cells by modulating the expression of β1 integrin.

    Science.gov (United States)

    Goldmann, Oliver; Tuchscherr, Lorena; Rohde, Manfred; Medina, Eva

    2016-06-01

    Mast cells (MCs) are important sentinels of the host defence against invading pathogens. We previously reported that Staphylococcus aureus evaded the extracellular antimicrobial activities of MCs by promoting its internalization within these cells via β1 integrins. Here, we investigated the molecular mechanisms governing this process. We found that S. aureus responded to the antimicrobial mediators released by MCs by up-regulating the expression of α-hemolysin (Hla), fibronectin-binding protein A and several regulatory systems. We also found that S. aureus induced the up-regulation of β1 integrin expression on MCs and that this effect was mediated by Hla-ADAM10 (a disintegrin and metalloproteinase 10) interaction. Thus, deletion of Hla or inhibition of Hla-ADAM10 interaction significantly impaired S. aureus internalization within MCs. Furthermore, purified Hla but not the inactive HlaH35L induced up-regulation of β1 integrin expression in MCs in a dose-dependent manner. Our data support a model in which S. aureus counter-reacts the extracellular microbicidal mechanisms of MCs by increasing expression of fibronectin-binding proteins and by inducing Hla-ADAM10-mediated up-regulation of β1 integrin in MCs. The up-regulation of bacterial fibronectin-binding proteins, concomitantly with the increased expression of its receptor β1 integrin on the MCs, resulted in enhanced S. aureus internalization through the binding of fibronectin-binding proteins to integrin β1 via fibronectin. © 2016 John Wiley & Sons Ltd.

  17. Antimicrobial susceptibility patterns and characterization of clinical isolates of Staphylococcus aureus in KwaZulu-Natal province, South Africa

    Directory of Open Access Journals (Sweden)

    Lin Johnson

    2006-07-01

    Full Text Available Abstract Background Antimicrobial resistance of Staphylococcus aureus especially methicillin-resistant S. aureus (MRSA continues to be a problem for clinicians worldwide. However, few data on the antibiotic susceptibility patterns of S. aureus isolates in South Africa have been reported and the prevalence of MRSA in the KwaZulu-Natal (KZN province is unknown. In addition, information on the characterization of S. aureus in this province is unavailable. This study investigated the susceptibility pattern of 227 S. aureus isolates from the KZN province, South Africa. In addition, characterization of methicillin-sensitive S. aureus (MSSA and MRSA are reported in this survey. Methods The in-vitro activities of 20 antibiotics against 227 consecutive non-duplicate S. aureus isolates from clinical samples in KZN province, South Africa were determined by the disk-diffusion technique. Isolates resistant to oxacillin and mupirocin were confirmed by PCR detection of the mecA and mup genes respectively. PCR-RFLP of the coagulase gene was employed in the characterization of MSSA and MRSA. Results All the isolates were susceptible to vancomycin, teicoplanin and fusidic acid, and 26.9% of isolates studied were confirmed as MRSA. More than 80% of MRSA were resistant to at least four classes of antibiotics and isolates grouped in antibiotype 8 appears to be widespread in the province. The MSSA were also susceptible to streptomycin, neomycin and minocycline, while less than 1% was resistant to chloramphenicol, ciprofloxacin, rifampicin and mupirocin. The inducible MLSB phenotype was detected in 10.8% of MSSA and 82% of MRSA respectively, and one MSSA and one MRSA exhibited high-level resistance to mupirocin. There was good correlation between antibiotyping and PCR-RFLP of the coagulase gene in the characterization of MRSA in antibiotypes 1, 5 and 12. Conclusion In view of the high resistance rates of MRSA to gentamicin, erythromycin, clindamycin, rifampicin and

  18. Stilbenes reduce Staphylococcus aureus hemolysis, biofilm formation, and virulence.

    Science.gov (United States)

    Lee, Kayeon; Lee, Jin-Hyung; Ryu, Shi Yong; Cho, Moo Hwan; Lee, Jintae

    2014-09-01

    Stilbenoids have a broad range of beneficial health effects. On the other hand, the emergence of antibiotic-resistant Staphylococcus aureus presents a worldwide problem that requires new antibiotics or nonantibiotic strategies. S. aureus produces α-hemolysin (a pore-forming cytotoxin) that has been implicated in the pathogenesis of sepsis and pneumonia. Furthermore, the biofilms formed by S. aureus constitute a mechanism of antimicrobial resistance. In this study, we investigated the hemolytic and antibiofilm activities of 10 stilbene-related compounds against S. aureus. trans-Stilbene and resveratrol at 10 μg/mL were found to markedly inhibit human blood hemolysis by S. aureus, and trans-stilbene also inhibited S. aureus biofilm formation without affecting its bacterial growth. Furthermore, trans-stilbene and resveratrol attenuated S. aureus virulence in vivo in the nematode Caenorhabditis elegans, which is normally killed by S. aureus. Transcriptional analysis showed that trans-stilbene repressed the α-hemolysin hla gene and the intercellular adhesion locus (icaA and icaD) in S. aureus, and this finding was in line with observed reductions in virulence and biofilm formation. In addition, vitisin B, a stilbenoid tetramer, at 1 μg/mL was observed to significantly inhibit human blood hemolysis by S. aureus.

  19. Staphylococcus aureus shifts towards commensalism in response to Corynebacterium species

    Directory of Open Access Journals (Sweden)

    Matthew M Ramsey

    2016-08-01

    Full Text Available Staphylococcus aureus–human interactions result in a continuum of outcomes from commensalism to pathogenesis. S. aureus is a clinically important pathogen that asymptomatically colonizes ~25% of humans as a member of the nostril and skin microbiota, where it resides with other bacteria including commensal Corynebacterium species. Commensal Corynebacterium spp. are also positively correlated with S. aureus in chronic polymicrobial diabetic foot infections, distinct from acute monomicrobial S. aureus infections. Recent work by our lab and others indicates that microbe-microbe interactions between S. aureus and human skin/nasal commensals, including Corynebacterium species, affect S. aureus behavior and fitness. Thus, we hypothesized that S. aureus interactions with Corynebacterium spp. diminish S. aureus virulence. We tested this by assaying for changes in S. aureus gene expression during in vitro mono- versus coculture with Corynebacterium striatum, a common skin and nasal commensal. We observed a broad shift in S. aureus gene transcription during in vitro growth with C. striatum, including increased transcription of genes known to exhibit increased expression during human nasal colonization and decreased transcription of virulence genes. S. aureus uses several regulatory pathways to transition between commensal and pathogenic states. One of these, the quorum signal accessory gene regulator (agr system, was strongly inhibited in response to Corynebacterium spp. Phenotypically, S. aureus exposed to C. striatum exhibited increased adhesion to epithelial cells, reflecting a commensal state, and decreased hemolysin activity, reflecting an attenuation of virulence. Consistent with this, S. aureus displayed diminished fitness in experimental in vivo coinfection with C. striatum when compared to monoinfection. These data support a model in which S. aureus shifts from virulence towards a commensal state when exposed to commensal Corynebacterium species.

  20. Staphylococcus aureus Shifts toward Commensalism in Response to Corynebacterium Species

    Science.gov (United States)

    Ramsey, Matthew M.; Freire, Marcelo O.; Gabrilska, Rebecca A.; Rumbaugh, Kendra P.; Lemon, Katherine P.

    2016-01-01

    Staphylococcus aureus–human interactions result in a continuum of outcomes from commensalism to pathogenesis. S. aureus is a clinically important pathogen that asymptomatically colonizes ~25% of humans as a member of the nostril and skin microbiota, where it resides with other bacteria including commensal Corynebacterium species. Commensal Corynebacterium spp. are also positively correlated with S. aureus in chronic polymicrobial diabetic foot infections, distinct from acute monomicrobial S. aureus infections. Recent work by our lab and others indicates that microbe–microbe interactions between S. aureus and human skin/nasal commensals, including Corynebacterium species, affect S. aureus behavior and fitness. Thus, we hypothesized that S. aureus interactions with Corynebacterium spp. diminish S. aureus virulence. We tested this by assaying for changes in S. aureus gene expression during in vitro mono- versus coculture with Corynebacterium striatum, a common skin and nasal commensal. We observed a broad shift in S. aureus gene transcription during in vitro growth with C. striatum, including increased transcription of genes known to exhibit increased expression during human nasal colonization and decreased transcription of virulence genes. S. aureus uses several regulatory pathways to transition between commensal and pathogenic states. One of these, the quorum signal accessory gene regulator (agr) system, was strongly inhibited in response to Corynebacterium spp. Phenotypically, S. aureus exposed to C. striatum exhibited increased adhesion to epithelial cells, reflecting a commensal state, and decreased hemolysin activity, reflecting an attenuation of virulence. Consistent with this, S. aureus displayed diminished fitness in experimental in vivo coinfection with C. striatum when compared to monoinfection. These data support a model in which S. aureus shifts from virulence toward a commensal state when exposed to commensal Corynebacterium species. PMID:27582729

  1. Meticillin-resistant Staphylococcus aureus (MRSA)

    DEFF Research Database (Denmark)

    Stefani, Stefania; Chung, Doo Ryeon; Lindsay, Jodi A

    2012-01-01

    decisions with regard to harmonisation of typing methods. A stratified, three-level organisation of testing laboratories was proposed: local; regional; and national. The functions of, and testing methodology used by, each laboratory were defined. The group consensus was to recommend spa and staphylococcal......This article reviews recent findings on the global epidemiology of healthcare-acquired/associated (HA), community-acquired/associated (CA) and livestock-associated (LA) meticillin-resistant Staphylococcus aureus (MRSA) and aims to reach a consensus regarding the harmonisation of typing methods...... health. Continuous efforts to understand the changing epidemiology of S. aureus infection in humans and animals are therefore necessary, not only for appropriate antimicrobial treatment and effective infection control but also to monitor the evolution of the species. The group made several consensus...

  2. Linezolid limits burden of methicillin-resistant Staphylococcus aureus in biofilm of tracheal tubes.

    Science.gov (United States)

    Fernández-Barat, Laia; Ferrer, Miquel; Sierra, Josep Maria; Soy, Dolors; Guerrero, Laura; Vila, Jordi; Li Bassi, Gianluigi; Cortadellas, Núria; Martínez-Olondris, Pilar; Rigol, Montserrat; Esperatti, Mariano; Luque, Néstor; Saucedo, Lina María; Agustí, Carlos; Torres, Antoni

    2012-08-01

    To evaluate the effects of systemic treatment with linezolid compared with vancomycin on biofilm formation in mechanically ventilated pigs with severe methicillin-resistant Staphylococcus aureus-induced pneumonia. Prospective randomized animal study. Departments of Pneumology, Microbiology, and Pharmacy of the Hospital Clínic, Barcelona, and Scientific and Technological Services of the University of Barcelona. We prospectively analyzed 70 endotracheal tube samples. Endotracheal tubes were obtained from pigs either untreated (controls, n=20), or treated with vancomycin (n=32) or linezolid (n=18). The endotracheal tubes were obtained from a previous randomized study in tracheally intubated pigs with methicillin-resistant Staphylococcus aureus severe pneumonia, and mechanically ventilated for 69±16 hrs. Distal and medial hemisections of the endotracheal tube were assessed to quantify methicillin-resistant Staphylococcus aureus burden, antibiotic biofilm concentration by high-performance liquid chromatography or bioassay, and biofilm thickness through scanning electron microscopy. We found a trend toward a significant variation in biofilm methicillin-resistant Staphylococcus aureus burden (log colony-forming unit/mL) among groups (p=.057), and the lowest bacterial burden was found in endotracheal tubes treated with linezolid (1.98±1.68) in comparison with untreated endotracheal tubes (3.72±2.20, p=.045) or those treated with vancomycin (2.97±2.43, p=.286). Biofilm linezolid concentration was 19-fold above the linezolid minimum inhibitory concentration, whereas biofilm vancomycin concentration (1.60±0.91 µg/mL) was consistently below or close to the vancomycin minimum inhibitory concentration. Biofilm was thicker in the vancomycin group (p=.077). Systemic treatment with linezolid limits endotracheal tube biofilm development and methicillin-resistant Staphylococcus aureus burden. The potential clinical usefulness of linezolid in decreasing the risk of biofilm

  3. Structural rationale for the modulation of abscess formation by Staphylococcus aureus capsular polysaccharides.

    Science.gov (United States)

    Tzianabos, A O; Wang, J Y; Lee, J C

    2001-07-31

    Staphylococcus aureus is a medically important bacterial pathogen that is a common cause of superficial and deep-seated abscesses in humans. Most S. aureus isolates produce either a serotype 5 or 8 capsular polysaccharide (CP) that has been shown to enhance bacterial virulence. We investigated the role of S. aureus CPs in modulating abscess formation in an experimental animal model of intraabdominal infection. Structural studies of CP8 revealed that it has a zwitterionic charge motif conferred by the negatively charged carboxyl group of N-acetylmannosaminuronic acid and free amino groups available on partially N-acetylated fucosamine residues. We report that purified CP5 and CP8 facilitated intraabdominal abscess formation in animals when given i.p. with a sterile cecal contents adjuvant. Chemical modifications that neutralized the positively or negatively charged groups on CP8 abrogated its ability to provoke abscesses. Rats prophylactically treated with CP8 s.c. were protected against abscess formation induced by homologous or heterologous zwitterionic polysaccharides. Likewise, treatment with CP8 protected against challenge with viable S. aureus strains PS80 (a capsule type 8 strain) or COL (a methicillin-resistant capsule type 5 strain). Purified CP8 was a potent activator of rat and human CD4(+) T cells in vitro. When transferred to naive rats, these activated T cells modulated the development of intraabdominal abscess formation. These results provide a structure/function rationale for abscess formation by S. aureus and expand the sphere of encapsulated organisms that interact directly with T cells to regulate this host response to bacterial infection.

  4. Identification of Staphylococcus aureus infection by aptamers directly radiolabeled with technetium-99m.

    Science.gov (United States)

    dos Santos, Sara Roberta; Rodrigues Corrêa, Cristiane; Branco de Barros, André Luís; Serakides, Rogéria; Fernandes, Simone Odília; Cardoso, Valbert Nascimento; de Andrade, Antero Silva Ribeiro

    2015-03-01

    Aptamers are oligonucleotides that have high affinity and specificity for their molecular targets which are emerging as a new class of molecules for radiopharmaceuticals development. In this study, aptamers selected to Staphylococcus aureus were evaluated for bacterial infection identification. Anti S. aureus aptamers were labeled with (99m)Tc by the direct method. The radiolabel yield and complex stability were assessed by thin-layer chromatography (TLC). Three groups of Swiss mice containing 6 animals each were used. The first group was infected intramuscularly in the right thigh with S. aureus. The second group was infected in the same way with C. albicans and the third group was injected with zymosan to induce aseptic inflammation. After 24 h, radiolabeled aptamers (22.2 MBq) were injected by the tail vein. The mice were euthanized 4 h post injection and tissue sample activities measured in a gamma counter. The (99m)Tc labeled aptamers were stable in saline, plasma and cystein excess. Radiolabeled aptamers showed increased uptake in the kidneys for all groups indicating a main renal excretion, which is consistent with the hydrophilic nature and small size of aptamers. The radiopharmaceutical showed rapid blood clearance indicated by a reduced dose (% ID/g) in the blood. The biodistribution showed that aptamers were able to identify the infection foci caused by S. aureus displaying a target/non-target ratio of 4.0±0.5. This ratio for mice infected with C. albicans was 2.0±0.4 while for mice with aseptic inflammation was 1.2±0.2. Histology confirmed the presence of infection in groups 1 and 2, and inflammation in group 3. The biodistibution study demonstrated a statistically higher uptake in the S. aureus foci relative to inflammation and C. albicans infected areas. These results highlight the potential of aptamers labeled directly with (99m)Tc for bacterial infection diagnosis by scintigraphy. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Novel Treatment of Staphylococcus aureus Device-Related Infections Using Fibrinolytic Agents.

    Science.gov (United States)

    Hogan, S; O'Gara, J P; O'Neill, E

    2018-02-01

    Staphylococcal infections involving biofilms represent a significant challenge in the treatment of patients with device-related infections. Staphylococcus aureus biofilms have been shown to be SaeRS regulated and dependent on the coagulase-catalyzed conversion of fibrinogen into fibrin on surfaces coated with human plasma. Here we investigated the treatment of staphylococcal biofilm device-related infections by digesting the fibrin biofilm matrix with and without existing antimicrobials. The fibrinolytic agents plasmin, streptokinase, and nattokinase, and TrypLE, a recombinant trypsin-like protease, were used to digest and treat S. aureus biofilms grown in vitro using in vivo-like static biofilm assays with and without antimicrobials. Cytotoxicity, the potential to induce a cytokine response in whole human blood, and the risk of induction of tolerance to fibrinolytic agents were investigated. A rat model of intravascular catheter infection was established to investigate the efficacy of selected fibrinolytic agents in vivo Under biomimetic conditions, the fibrinolytic agents effectively dispersed established S. aureus biofilms and, in combination with common antistaphylococcal antimicrobials, effectively killed bacterial cells being released from the biofilm. These fibrinolytic agents were not cytotoxic and did not affect the host immune response. The rat model of infection successfully demonstrated the activity of the selected fibrinolytic agents alone and in combination with antimicrobials on established biofilms in vivo TrypLE and nattokinase most successfully removed adherent cells from plasma-coated surfaces and significantly improved the efficacy of existing antimicrobials against S. aureus biofilms in vitro and in vivo These biofilm dispersal agents represent a viable future treatment option for S. aureus device-related infections. Copyright © 2018 American Society for Microbiology.

  6. Exploring the contribution of efflux on the resistance to fluoroquinolones in clinical isolates of Staphylococcus aureus

    LENUS (Irish Health Repository)

    Costa, Sofia SANTOS

    2011-10-27

    Abstract Background Antimicrobial resistance mediated by efflux systems is still poorly characterized in Staphylococcus aureus, despite the description of several efflux pumps (EPs) for this bacterium. In this work we used several methodologies to characterize the efflux activity of 52 S. aureus isolates resistant to ciprofloxacin collected in a hospital in Lisbon, Portugal, in order to understand the role played by these systems in the resistance to fluoroquinolones. Results Augmented efflux activity was detected in 12 out of 52 isolates and correlated with increased resistance to fluoroquinolones. Addition of efflux inhibitors did not result in the full reversion of the fluoroquinolone resistance phenotype, yet it implied a significant decrease in the resistance levels, regardless of the type(s) of mutation(s) found in the quinolone-resistance determining region of grlA and gyrA genes, which accounted for the remaining resistance that was not efflux-mediated. Expression analysis of the genes coding for the main efflux pumps revealed increased expression only in the presence of inducing agents. Moreover, it showed that not only different substrates can trigger expression of different EP genes, but also that the same substrate can promote a variable response, according to its concentration. We also found isolates belonging to the same clonal type that showed different responses towards drug exposure, thus evidencing that highly related clinical isolates may diverge in the efflux-mediated response to noxious agents. The data gathered by real-time fluorometric and RT-qPCR assays suggest that S. aureus clinical isolates may be primed to efflux antimicrobial compounds. Conclusions The results obtained in this work do not exclude the importance of mutations in resistance to fluoroquinolones in S. aureus, yet they underline the contribution of efflux systems for the emergence of high-level resistance. All together, the results presented in this study show the potential

  7. Mechanisms of Gentamicin Resistance in Staphylococcus aureus

    Science.gov (United States)

    Dowding, J. E.

    1977-01-01

    Three clinical isolates of Staphylococcus aureus resistant to gentamicin and other aminoglycosides have been examined for antibiotic modifying enzymes. The strains contain a number of these enzymes, most of them similar to those commonly found in aminoglycoside-resistant gram-negative strains. All three strains (and a transductant derived from one of them) contain two enzymes mediating gentamicin resistance, an aminoglycoside 6′-N-acetyltransferase and a novel enzyme, gentamicin phosphotransferase. PMID:836013

  8. [Staphylococcus aureus in bulk milk samples].

    Science.gov (United States)

    Benda, P; Vyletĕlová, M

    1995-07-01

    In the years 1993-1994 the occurrence of Staphylococcus aureus was investigated in bulk milk samples in the area where a Baby Food Factory at Zábreh in Moravia is located, and in Bruntál, Zlín and Policka districts. Evaluation of the results was based on ECC Directive 92/46, while the dynamics of S. aureus presence was followed for the whole period of observation as well as in the particular seasons. A total of 4,485 samples was processed. Out of these, 50.7% contained less than 100 CFU/ml of S. aureus, 41.4% contained 100-500 CFU/ml, 6.73% 500-2,000 CFU/ml and 1.14% contained more than 2,000 CFU/ml (Fig. 1). The samples were divided into three categories: private new-established farms, cooperative and State-owned enterprises in the area of the Zábĕh Factory and others (Zlín, Bruntál and Policka districts). There were highly significant differences in the content of staphylococci (P = 0.01%) between the three categories of samples. Ninety-eight percent of samples from private farms, 96% samples from the Zábreh Factory area and 85% of the other samples comply with the regulation EEC 92/64 (Tab. I) for raw cow's milk for the manufacture of products "made with raw milk" whose manufacturing process does not involve any heat treatment (Fig. 2). The occurrence of S. aureus in the Zábreh Factory area shows an expressive seasonal dynamics (P = 0.005%) with maximum values in winter months (December-March) and minimum values in summer months (July-October)-Fig. 3. The same relationship can be seen on more extensive data files for the particular producers (Fig. 4).(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Effects of vitamin D and its metabolites on cell viability and Staphylococcus aureus invasion in bovine mammary epithelial cells

    DEFF Research Database (Denmark)

    Yue, Yuan; Hymøller, Lone; Jensen, Søren Krogh

    2017-01-01

    Vitamin D has been found have various biological effects that may be potent in preventing bovine mastitis. Two forms of vitamin D, vitamin D2 (D2) and vitamin D3 (D3), can be hydroxylated to functional metabolites in cattle. The objectives of the present study were to investigate the effects of D2......-treated with 25(OH)D2 reduced S. aureus adhesion while pre-treatment with 25(OH)D3 inhibited S. aureus invasion, but neither of the compounds attenuated the S. aureus-induced gene expression reduction. In conclusion, the present study showed that D2 compounds have comparable effects on cell proliferation...... and bacterial invasion to their D3 analogues in vitro, suggesting that D2 and its metabolites may also be effective in the defense against bacterial infection....

  10. In vitro bactericidal efficacy of atmospheric-pressure plasma jet on titanium-based implant infected with Staphylococcus aureus

    Science.gov (United States)

    Park, Young-Ouk; Lee, Chang-Min; Kim, Myung-Sun; Jung, Sang-Chul; Yang, Seong-Won; Kook, Min-Suk; Kim, Byung-Hoon

    2017-01-01

    Staphylococcus aureus is a representative of gram-positive bacteria that causes skin infection, respiratory diseases, and burned tissue infections. The aim of this study was to evaluate the sterilizing efficiency of an atmospheric-pressure plasma jet (APPJ) on S. aureus adhered on a titanium surface. During the APPJ sterilization, the plasma gases used were Ar, Ar+N2, and Ar+O2. With increasing APPJ treatment time, the viability of S. aureus decreased. The addition of O2 gas to Ar gas resulted in a higher sterilizing efficiency than the addition of other groups. Plasma exposure induced bacterial oxidative stress, and it was confirmed that the cell membrane was seriously damaged by the production of reactive oxygen species. Our finding suggests that the APPJ is an effective tool for clinical antimicrobial therapy.

  11. SpA, ClfA, and FnbA Genetic Variations Lead to Staphaurex Test-Negative Phenotypes in Bovine Mastitis Staphylococcus aureus Isolates▿

    Science.gov (United States)

    Stutz, Katrin; Stephan, Roger; Tasara, Taurai

    2011-01-01

    Staphylococcus aureus encodes many proteins that act as virulence factors, leading to a variety of diseases, including mastitis in cows. Among these virulence factors, SpA, ClfA, ClfB, FnbA, and FnbB are important for the ability of S. aureus to adhere to and invade host cells as well as to evade host immune responses. The interaction between these S. aureus surface proteins and human immunoglobulin G and fibrinogen that are coupled to latex particles is utilized to induce latex agglutination reactions, which are used widely in diagnostic kits for confirmation of presumptive S. aureus isolates. In this study, the Staphaurex latex agglutination test was performed on a collection of confirmed bovine mastitis S. aureus isolates. Notably, 54% (43/79 isolates) of these isolates exhibited latex agglutination-negative phenotypes (Staphaurex-negative result). To gain insights into the reasons for the high frequency of Staphaurex-negative bovine mastitis S. aureus isolates, the spa, clfA, clfB, fnbA, and fnbB genes were examined. Specific genetic changes in spa, clfA, and fnbA, as well as a loss of fnbB, which may impair SpA, ClfA, FnbA, and FnbB functions in latex agglutination reactions, were detected in Staphaurex-negative S. aureus isolates. The genetic changes included a premature stop codon in the spa gene, leading to a truncated SpA protein that is unable to participate in S. aureus cell-mediated agglutination of latex particles. In addition, clfA and fnbA genetic polymorphisms were detected that were linked to ClfA and FnbA amino acid changes that may significantly reduce fibrinogen-binding activity. The genetic variations in these S. aureus isolates might also have implications for their bovine mastitis virulence capacity. PMID:21147952

  12. Staphylococcus aureus sigma B-dependent emergence of small-colony variants and biofilm production following exposure to Pseudomonas aeruginosa 4-hydroxy-2-heptylquinoline-N-oxide

    Directory of Open Access Journals (Sweden)

    Michaud Sophie

    2010-01-01

    Full Text Available Abstract Background Staphylococcus aureus and Pseudomonas aeruginosa are often found together in the airways of cystic fibrosis (CF patients. It was previously shown that the P. aeruginosa exoproduct 4-hydroxy-2-heptylquinoline-N-oxide (HQNO suppresses the growth of S. aureus and provokes the emergence of small-colony variants (SCVs. The presence of S. aureus SCVs as well as biofilms have both been associated with chronic infections in CF. Results We demonstrated that HQNO stimulates S. aureus to form a biofilm in association with the formation of SCVs. The emergence of SCVs and biofilm production under HQNO exposure was shown to be dependent on the activity of the stress- and colonization-related alternative sigma factor B (SigB. Analysis of gene expression revealed that exposure of a prototypical S. aureus strain to HQNO activates SigB, which was leading to an increase in the expression of the fibronectin-binding protein A and the biofilm-associated sarA genes. Conversely, the quorum sensing accessory gene regulator (agr system and the α-hemolysin gene were repressed by HQNO. Experiments using culture supernatants from P. aeruginosa PAO1 and a double chamber co-culture model confirmed that P. aeruginosa stimulates biofilm formation and activates SigB in a S. aureus strain isolated from a CF patient. Furthermore, the supernatant from P. aeruginosa mutants unable to produce HQNO induced the production of biofilms by S. aureus to a lesser extent than the wild-type strain only in a S. aureus SigB-functional background. Conclusions These results suggest that S. aureus responds to HQNO from P. aeruginosa by forming SCVs and biofilms through SigB activation, a phenomenon that may contribute to the establishment of chronic infections in CF patients.

  13. [Change in drug resistance of Staphylococcus aureus].

    Science.gov (United States)

    Lin, Yan; Liu, Yan; Luo, Yan-Ping; Liu, Chang-Ting

    2013-11-01

    To analyze the change in drug resistance of Staphylococcus aureus (SAU) in the PLA general hospital from January 2008 to December 2012, and to provide solid evidence to support the rational use of antibiotics for clinical applications. The SAU strains isolated from clinical samples in the hospital were collected and subjected to the Kirby-Bauer disk diffusion test. The results were assessed based on the 2002 American National Committee for Clinical Laboratory Standards (NCCLS) guidelines. SAU strains were mainly isolated from sputum, urine, blood and wound excreta and distributed in penology, neurology wards, orthopedics and surgery ICU wards. Except for glycopeptide drugs, methicillin-resistant Staphylococcus aureus (MRSA) had a higher drug resistance rate than those of the other drugs and had significantly more resistance than methicillin-sensitive Staphylococcus aureus (MSSA) (P resistance, we discovered a gradual increase in drug resistance to fourteen test drugs during the last five years. Drug resistance rate of SAU stayed at a higher level over the last five years; moreover, the detection ratio of MRSA keeps rising year by year. It is crucial for physicians to use antibiotics rationally and monitor the change in drug resistance in a dynamic way.

  14. Immunopathogenesis of Staphylococcus aureus pulmonary infection

    Science.gov (United States)

    Parker, Dane; Prince, Alice

    2013-01-01

    Staphylococcus aureus is a common human pathogen highly evolved as both a component of the commensal flora and as a major cause of invasive infection. Severe respiratory infection due to staphylococci has been increasing due to the prevalence of more virulent USA300 CA-MRSA strains in the general population. The ability of S. aureus to adapt to the milieu of the respiratory tract has facilitated its emergence as a respiratory pathogen. Its metabolic versatility, the ability to scavenge iron, coordinate gene expression, and the horizontal acquisition of useful genetic elements have all contributed to its success as a component of the respiratory flora, in hospitalized patients, as a complication of influenza and in normal hosts. The expression of surface adhesins facilitates its persistence in the airways. In addition, the highly sophisticated interactions of the multiple S. aureus virulence factors, particularly the α-hemolysin and protein A, with diverse immune effectors in the lung such as ADAM10, TNFR1, EGFR, immunoglobulin, and complement all contribute to the pathogenesis of staphylococcal pneumonia. PMID:22037948

  15. Antimicrobial efficacy of Syzygium antisepticum plant extract against Staphylococcus aureus and methicillin-resistant S. aureus and its application potential with cooked chicken.

    Science.gov (United States)

    Yuan, Wenqian; Yuk, Hyun-Gyun

    2018-06-01

    For the past decades, there has been a growing demand for natural antimicrobials in the food industry. Plant extracts have attracted strong research interests due to their wide-spectrum antimicrobial activities, but only a limited number have been investigated thoroughly. The present study aimed at identifying a novel anti-staphylococcal plant extract, to validate its activity in a food model, and to investigate on its composition and antimicrobial mechanism. Four plant extracts were evaluated against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in vitro, with Syzygium antisepticum leaf extract showing the strongest antimicrobial activity (MIC = 0.125 mg/mL). Relatively high total phenolic content (276.3 mg GAE/g extract) and antioxidant activities (90.2-138.0 mg TE/g extract) were measured in S. antisepticum extract. Food validation study revealed that higher extract concentration (32 mg/mL) was able to inhibit or reduce staphylococcal growth in cooked chicken, but caused color change on meat surface. By GC-MS, β-caryophyllene (12.76 area%) was identified as the dominant volatile compound in extract. Both crude extract and pure β-caryophyllene induced membrane damages in S. aureus. These results suggested good anti-staphylococcal properties of S. antisepticum plant extract, identified its major volatile composition and its membrane-damaging antimicrobial mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Comparison of the BBL CHROMagar Staph aureus agar medium to conventional media for detection of Staphylococcus aureus in respiratory samples.

    Science.gov (United States)

    Flayhart, Diane; Lema, Clara; Borek, Anita; Carroll, Karen C

    2004-08-01

    Screening for Staphylococcus aureus has become routine in certain patient populations. This study is the first clinical evaluation of the BBL CHROMagar Staph aureus agar (CSA) medium (BD Diagnostics, Sparks, Md.) for detection of S. aureus in nasal surveillance cultures and in respiratory samples from cystic fibrosis (CF) patients. S. aureus colonies appear mauve on CSA. Other organisms are inhibited or produce a distinctly different colony color. S. aureus was identified from all media by slide coagulase, exogenous DNase, and mannitol fermentation assays. Susceptibility testing was performed using the agar dilution method. A total of 679 samples were evaluated. All samples were inoculated onto CSA. Nasal surveillance cultures were inoculated onto sheep blood agar (SBA) (BD Diagnostics), and samples from CF patients were inoculated onto mannitol salt agar (MSA) (BD Diagnostics). Of the 679 samples cultured, 200 organisms produced a mauve color on CSA (suspicious for S. aureus) and 180 were positive for S. aureus on SBA or MSA. Of 200 CSA-positive samples 191 were identified as S. aureus. Nine mauve colonies were slide coagulase negative and were subsequently identified as Staphylococcus lugdunensis (one), Staphylococcus epidermidis (three), Staphylococcus haemolyticus (one), and Corynebacterium species (four). CSA improved the ability to detect S. aureus by recovering 12 S. aureus isolates missed by conventional media. Of the 192 S. aureus isolates recovered, 122 were methicillin susceptible and 70 were methicillin resistant. Overall, the sensitivity and specificity of CSA in this study were 99.5 and 98%, respectively. There was no difference in the performance of the slide coagulase test or in susceptibility testing performed on S. aureus recovered from CSA compared to SBA or MSA. Our data support the use of CSA in place of standard culture media for detection of S. aureus in heavily contaminated respiratory samples.

  17. Factors determining Staphylococcus aureus susceptibility to photoantimicrobial chemotherapy: RsbU activity, staphyloxanthin level and membrane fluidity.

    Directory of Open Access Journals (Sweden)

    Monika Kossakowska-Zwierucho

    2016-07-01

    Full Text Available Photoantimicrobial chemotherapy (PACT constitutes a particular type of stress condition, in which bacterial cells induce a pleiotropic and as yet unexplored effect. In light of this, the key master regulators are of putative significance to the overall phototoxic outcome. In Staphylococcus aureus, the alternative sigma factor σB controls the expression of genes involved in the response to environmental stress. We show that aberration of any sigB operon genes in S. aureus USA300 isogenic mutants causes a pronounced sensitization (>5 log10 reduction in CFU drop to PACT with selected photosensitizers, namely protoporphyrin diarginate, zinc phthalocyanine and rose bengal. This effect is partly due to aberration-coupled staphyloxanthin synthesis inhibition. We identified frequent mutations in RsbU, a σB activator, in PACT-vulnerable clinical isolates of S. aureus, resulting in σB activity impairment. Locations of significant changes in protein structure (IS256 insertion, early STOP codon occurrence, substitutions A230T and A276D were shown in a theoretical model of S. aureus RsbU. As a phenotypic hallmark of PACT-vulnerable S. aureus strains, we observed an increased fluidity of bacterial cell membrane, which is a result of staphyloxanthin content and other yet unidentified factors. Our research indicates σB as a promising target of adjunctive antimicrobial therapy and suggests that enhanced cell membrane fluidity may be an adjuvant strategy in photoantimicrobial chemotherapy.

  18. Redox sensing by a Rex-family repressor is involved in the regulation of anaerobic gene expression in Staphylococcus aureus.

    Science.gov (United States)

    Pagels, Martin; Fuchs, Stephan; Pané-Farré, Jan; Kohler, Christian; Menschner, Leonhard; Hecker, Michael; McNamarra, Peter J; Bauer, Mikael C; von Wachenfeldt, Claes; Liebeke, Manuel; Lalk, Michael; Sander, Gunnar; von Eiff, Christof; Proctor, Richard A; Engelmann, Susanne

    2010-06-01

    An alignment of upstream regions of anaerobically induced genes in Staphylococcus aureus revealed the presence of an inverted repeat, corresponding to Rex binding sites in Streptomyces coelicolor. Gel shift experiments of selected upstream regions demonstrated that the redox-sensing regulator Rex of S. aureus binds to this inverted repeat. The binding sequence--TTGTGAAW(4)TTCACAA--is highly conserved in S. aureus. Rex binding to this sequence leads to the repression of genes located downstream. The binding activity of Rex is enhanced by NAD+ while NADH, which competes with NAD+ for Rex binding, decreases the activity of Rex. The impact of Rex on global protein synthesis and on the activity of fermentation pathways under aerobic and anaerobic conditions was analysed by using a rex-deficient strain. A direct regulatory effect of Rex on the expression of pathways that lead to anaerobic NAD+ regeneration, such as lactate, formate and ethanol formation, nitrate respiration, and ATP synthesis, is verified. Rex can be considered a central regulator of anaerobic metabolism in S. aureus. Since the activity of lactate dehydrogenase enables S. aureus to resist NO stress and thus the innate immune response, our data suggest that deactivation of Rex is a prerequisite for this phenomenon.

  19. Colonization of epidermal tissue by Staphylococcus aureus produces localized hypoxia and stimulates secretion of antioxidant and caspase-14 proteins

    Energy Technology Data Exchange (ETDEWEB)

    Lone , Abdul G.; Atci, Erhan; Renslow, Ryan S.; Beyenal, Haluk; Noh, S.; Fransson, B.; Abu-Lail, Nehal; Park, Jeong-Jin; Gang, David R.; Call, Douglas R.

    2015-08-31

    A partial-thickness epidermal explant model was colonized with GFP-expressing S. aureus and the pattern of S. aureus biofilm growth was characterized using electron and confocal laser scanning microscopy. Oxygen concentration in explants was quantified using microelectrodes. The relative effective diffusivity and porosity of the epidermis were determined using magnetic resonance imaging, while hydrogen peroxide (H2O2) concentration in explant media was measured by using microelectrodes. Secreted proteins were identified and quantified using MSE mass spectrometry. We found that S. aureus biofilm grows predominantly in sebum-rich areas around hair follicles and associated skin folds. Dissolved oxygen was selectively depleted (2-3 fold) in these locations, but the relative effective diffusivity and porosity did not change between colonized and control epidermis. Histological analysis revealed keratinocyte damage across all the layers of colonized epidermis after four days of culture. The colonized explants released significantly (P< 0.01) more anti-oxidant proteins of both epidermal and S. aureus origin, consistent with elevated H2O2 concentration found in the media from the colonized explants (P< 0.001). Caspase-14 was also elevated significantly in media from infected explants. While H2O2 induces primary keratinocyte differentiation, caspase-14 is required for terminal keratinocyte differentiation and desquamation. These results are consistent with a localized biological impact from S. aureus in response to colonization of the skin surface.

  20. Magnetic nanoparticle targeted hyperthermia of cutaneous Staphylococcus aureus infection

    Science.gov (United States)

    Kim, Min-Ho; Yamayoshi, Itsukyo; Mathew, Steven; Liln, Hubert; Nayfach, Joseph; Simon, Scott I.

    2013-01-01

    The incidence of wound infections that do not adequately respond to standard-of-care antimicrobial treatment has been increasing. To address this challenge, a novel antimicrobial magnetic thermotherapy platform has been developed in which a high-amplitude, high-frequency, alternating magnetic field (AMF) is used to rapidly heat magnetic nanoparticles that are bound to Staphylococcus aureus (S. aureus). The antimicrobial efficacy of this platform was evaluated in the treatment of both an in vitro culture model of S. aureus biofilm and a mouse model of cutaneous S. aureus infection. We demonstrated that an antibody-targeted magnetic nanoparticle bound to S. aureus was effective at thermally inactivating S. aureus and achieving accelerated wound healing without causing tissue injury. PMID:23149904

  1. Staphylococcus aureus nasal carriage in hemodialysis centers of Fez, Morocco

    OpenAIRE

    Idrissa Diawara; Khadija Bekhti; Driss Elhabchi; Rachid Saile; Naima Elmdaghri; Mohammed Timinouni; Mohamed Elazhari

    2014-01-01

    Background and objectives Staphylococcus aureus (S. aureus) nasal carriage may be responsible for some serious infections in hemodialyzed patients. The main target of this study was to estimate the prevalence of S. aureus nasal carriage in hemodialysis outpatients and medical staff in hemodialysis centers specifically in Fez region. The second target is to identify the risks of colonization, resistance pattern of isolates and their virulence toxin genes. Patients and Methods Nasal swab specim...

  2. Adenosine derived from Staphylococcus aureus-engulfed macrophages functions as a potent stimulant for the induction of inflammatory cytokines in mast cells

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Kim, Chan-Hee; Ryu, Kyoung-Hwa

    2011-01-01

    In this study, we attempted to isolate novel mast cell-stimulating molecules from Staphylococcus aureus. Water-soluble extract of S. aureus cell lysate strongly induced human interleukin- 8 in human mast cell line-1 and mouse interleukin-6 in mouse bone marrow-derived mast cells. The active...... adenosine receptor blocker, verified that purified adenosine can induce interleukin-8 production via adenosine receptors on mast cells. Moreover, adenosine was purified from S. aureusengulfed RAW264.7 cells, a murine macrophage cell line, used to induce phagocytosis of S. aureus. These results show a novel...... view of the source of exogenous adenosine in vivo and provide a mechanistic link between inflammatory disease and bacterial infection....

  3. Penetration of antibiotics through Staphylococcus aureus and Staphylococcus epidermidis biofilms

    National Research Council Canada - National Science Library

    Singh, Rachna; Ray, Pallab; Das, Anindita; Sharma, Meera

    2010-01-01

    This study was carried out to elucidate the role of reduced antibiotic penetration in the resistance of Staphylococcus aureus and Staphylococcus epidermidis biofilms to different antibiotics. The biofilms...

  4. Comparison of five tests for identification of Staphylococcus aureus from clinical samples

    NARCIS (Netherlands)

    A. Luijendijk (Ad); A.F. van Belkum (Alex); J.A.J.W. Kluytmans (Jan); H.A. Verbrugh (Henri)

    1996-01-01

    textabstractFive different laboratory tests for the identification of Staphylococcus aureus were compared. Analyses of 271 presumptive S. aureus strains, supplemented with 59 well-defined methicillin-resistant S. aureus (MRSA) isolates, were performed. Only the

  5. Factors involved in the early pathogenesis of bovine Staphylococcus aureus mastitis with emphasis on bacterial adhesion and invasion. A review.

    Science.gov (United States)

    Kerro Dego, O; van Dijk, J E; Nederbragt, H

    2002-12-01

    Staphylococcus aureus is the most important and prevalent contagious mammary pathogen; it causes clinical and subclinical intramammary infection with serious economic loss and herd management problems in dairy cows. In vitro studies have shown that Staphylococcus aureus adheres to mammary epithelial cells and extracellular matrix components and invades into mammary epithelial as well as other mammary cells. Staphylococcus aureus strains from intramammary infection produce several cell surface-associated and extracellular secretory products. The exact pathogenic roles of most of the products and their effects on adhesion and invasion are not well evaluated. It is also known that mammary epithelial cell-associated molecules and extracellular matrix components interact with S. aureus during the pathogenesis of mastitis, but their roles on adhesion and invasion have not been characterized. The adhesion of S. aureus to epithelial cells may involve non-specific physicochemical interactions and/or specific interactions between bacterial cell-associated ligands and host cell surface receptors. In vitro adhesion depends on the S. aureus strain, the growth phase of the bacteria, the growth medium and the origin of the epithelial cells. Adhesion is hypothesized to be a prerequisite and crucial early step for mammary gland infection. Staphylococcus aureus invades mammary epithelial cells. It also invades other cells such as endothelial cells and fibroblasts. Bacteria are found enclosed in membrane bound vacuoles in the cytoplasm of mammary epithelial cells. Recent observations indicate that S. aureus escapes from the phagosome into the cytoplasm and induces apoptosis. The invasion into mammary epithelial cells may occur through an endocytic process that requires involvement of elements of the cytoskeleton or by direct binding of bacteria to epithelial cells through a process mediated by specific receptors that needs de novo protein synthesis by both cells. Thus, the recurrent

  6. Differential induction of inflammatory cytokines and reactive oxygen species in murine peritoneal macrophages and resident fresh bone marrow cells by acute staphylococcus aureus infection: contribution of toll-like receptor 2 (TLR2).

    Science.gov (United States)

    Nandi, Ajeya; Dey, Somrita; Biswas, Julie; Jaiswal, Pooja; Naaz, Shamreen; Yasmin, Tamima; Bishayi, Biswadev

    2015-02-01

    Among the known Toll-like receptors (TLRs), Toll-like receptor 2 (TLR2) is a key sensor for detecting Staphylococcus aureus invasion. But the function of TLR2 during S. aureus infection in different cell populations is unclear. Two different cell subtypes were chosen to study the interaction of S. aureus with TLR2 because macrophages are extremely different from one compartment to another and their capacity to respond to live bacteria or bacterial products differs from one site to another. The contribution of TLR2 to the host innate response against acute live S. aureus infection and heat-killed S. aureus (HKSA) using anti-TLR2 antibody in murine peritoneal macrophages and resident fresh bone marrow cells has been investigated here. TLR2 blocking before infection induces the release of interleukin (IL)-10 by macrophages thereby inhibiting excessive production of oxidants by activating antioxidant enzymes. TLR2-blocked peritoneal macrophages showed impaired release of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and IL-6 in response to both live and heat-killed S. aureus infection except bone marrow cells. TLR2-mediated free radical production and killing of S. aureus were modulated by TLR2 blocking in peritoneal macrophages and resident bone marrow cells. This study supported that S. aureus persists in resident bone marrow cells in a state of quiescence.

  7. Staphylococcus aureus biofilm formation at the physiologic glucose concentration depends on the S. aureus lineage

    NARCIS (Netherlands)

    Croes, Sander; Deurenberg, Ruud H; Boumans, Marie-Louise L; Beisser, Patrick S; Neef, Cees; Stobberingh, Ellen E

    2009-01-01

    BACKGROUND: Since bacteria embedded in biofilms are far more difficult to eradicate than planktonic infections, it would be useful to know whether certain Staphylococcus aureus lineages are especially involved in strong biofilm formation. For this reason, in vitro biofilm formation of 228 clinical

  8. α-cyperone alleviates lung cell injury caused by Staphylococcus aureus via attenuation of α-hemolysin expression.

    Science.gov (United States)

    Luo, Mingjing; Qiu, Jiazhang; Zhang, Yu; Wang, Jianfeng; Dong, Jing; Li, Hongen; Leng, Bingfeng; Zhang, Qian; Dai, Xiaohan; Niu, Xiaodi; Zhao, Shuhua; Deng, Xuming

    2012-08-01

    In this study, we aimed to evaluate the effect of α- cyperone on S. aureus. We used a hemolysin test to examine the hemolytic activity in supernatants of S. aureus cultured with increasing concentrations of α- cyperone. In addition, we evaluated the production of α- hemolysin (Hla) by Western blotting. Real-time RT-PCR was performed to test the expression of hla (the gene encoding Hla) and agr (accessory gene regulator). Furthermore, we investigated the protective effect of α- cyperone on Hla-induced injury of A549 lung cells by live/ dead and cytotoxicity assays. We showed that in the presence of subinhibitory concentrations of α-cyperone, Hla production was markedly inhibited. Moreover, α- cyperone protected lung cells from Hla-induced injury. These findings indicate that α-cyperone is a promising inhibitor of Hla production by S. aureus and protects lung cells from this bacterium. Thus, α-cyperone may provide the basis for a new strategy to combat S. aureus pneumonia.

  9. Community-acquired methicillin-resistant Staphylococcus aureus carriage rate and antimicrobial susceptibility in a tertiary center, Iran.

    Science.gov (United States)

    Shokouhi, Shervin; Darazam, Ilad Alavi; Zamanian, Mohammad-Hossein

    2017-01-01

    This study was aimed to determine frequency and antimicrobial susceptibility of Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) among colonized patients in outpatient status. A total of 2000 nasal nares specimens were collected and inoculated on mannitol salt agar. MRSAs were identified based on mannitol positivity and coagulase test followed by cefoxitin disc diffusion test. Antimicrobial susceptibility of MRSA isolates was performed by E-test method for vancomycin and doxycycline as well as disc diffusion method for sulfamethoxazole-trimethoprim (SMX-TMP), erythromycin, linezolid, and clindamycin. D-test was performed for detection of inducible resistance to clindamycin. Overall, nasal carrier rate of S. aureus and CA-MRSA was estimated 22% and 1.25%, respectively. Out of the 440 S. aureus isolates, 25 isolates were MRSA. All were susceptible to vancomycin and linezolid, and susceptibility rates to SMX-TMP, erythromycin, levofloxacin, doxycycline, and clindamycin were 68%, 44%, 48%, 40% and 44%, respectively; furthermore, 28.5% of resistant isolates to erythromycin had inducible resistance to clindamycin. It seems susceptibility to clindamycin and SMX-TMP, recommended agents for empirical treatment of suspected CA-MRSA, are not promising. Vancomycin and linezolid are effective and reliable antibiotics for the treatment of S. aureus infections.

  10. Community-acquired methicillin-resistant Staphylococcus aureus carriage rate and antimicrobial susceptibility in a tertiary center, Iran

    Directory of Open Access Journals (Sweden)

    Shervin Shokouhi

    2017-01-01

    Full Text Available Background: This study was aimed to determine frequency and antimicrobial susceptibility of Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA among colonized patients in outpatient status. Materials and Methods: A total of 2000 nasal nares specimens were collected and inoculated on mannitol salt agar. MRSAs were identified based on mannitol positivity and coagulase test followed by cefoxitin disc diffusion test. Antimicrobial susceptibility of MRSA isolates was performed by E-test method for vancomycin and doxycycline as well as disc diffusion method for sulfamethoxazole-trimethoprim (SMX-TMP, erythromycin, linezolid, and clindamycin. D-test was performed for detection of inducible resistance to clindamycin. Results: Overall, nasal carrier rate of S. aureus and CA-MRSA was estimated 22% and 1.25%, respectively. Out of the 440 S. aureus isolates, 25 isolates were MRSA. All were susceptible to vancomycin and linezolid, and susceptibility rates to SMX-TMP, erythromycin, levofloxacin, doxycycline, and clindamycin were 68%, 44%, 48%, 40% and 44%, respectively; furthermore, 28.5% of resistant isolates to erythromycin had inducible resistance to clindamycin. Conclusion: It seems susceptibility to clindamycin and SMX-TMP, recommended agents for empirical treatment of suspected CA-MRSA, are not promising. Vancomycin and linezolid are effective and reliable antibiotics for the treatment of S. aureus infections.

  11. In vitro antimicrobial effects and mechanism of atmospheric-pressure He/O2 plasma jet on Staphylococcus aureus biofilm

    Science.gov (United States)

    Xu, Zimu; Shen, Jie; Cheng, Cheng; Hu, Shuheng; Lan, Yan; Chu, Paul K.

    2017-03-01

    The antimicrobial effects and associated mechanism of inactivation of Staphylococcus aureus (S. aureus) NCTC-8325 biofilms induced by a He/O2 atmospheric-pressure plasma jet (APPJ) are investigated in vitro. According to CFU (colony forming units) counting and the resazurin-based assay, the 10 min He/O2 (0.5%) APPJ treatment produces the optimal inactivation efficacy (>5 log10 ml-1) against the S. aureus biofilm and 5% of the bacteria enter a viable but non-culturable (VBNC) state. Meanwhile, 94% of the bacteria suffer from membrane damage according to SYTO 9/PI counterstaining. Scanning electron microscopy (SEM) reveals that plasma exposure erodes the extracellular polymeric substances (EPS) and then the cellular structure. The H2DCFDA-stained biofilms show larger concentrations of intracellular reactive oxygen species (ROS) in membrane-intact bacteria with increasing plasma dose. The admixture of oxygen in the working gas highly contributes to the deactivation efficacy of the APPJ against S. aureus and the plasma-induced endogenous ROS may work together with the discharge-generated ROS to continuously damage the bacterial membrane structure leading to deactivation of the biofilm microbes.

  12. Staphylococcus aureus: resistance pattern and risk factors

    Directory of Open Access Journals (Sweden)

    Mohammad Naghavi-Behzad

    2015-03-01

    Full Text Available Introduction: Methicillin resistant Staphylococcus aureus (MRSA has emerged as a nosocomial pathogen of major worldwide importance and is an increasingly frequent cause of community-acquired infections. In this study, different risk factors and MRSA resistance pattern were investigated. Methods: In a 24 months period, all of the patients who were confined to bed in the surgery ward were included in the study. Then they were assessed to find out as if they had MRSA infection when hospitalized and once when they were discharged. Almost 48 h after admission, when patients were discharged, social and medical histories were acquired. Acquired samples were examined. Results: During the present study of 475 patients, 108 patients (22.8% had S. aureus. About frequency of antibiotic resistance among collected S. aureus colonies, erythromycin resistance, was the most frequent antibiotic resistance, also resistance to vancomycin was 0.4% that was the least. Only hospitalization duration had statistically significant correlation with antibiotic resistance, also resistance to erythromycin had statistically significant relation with history of surgery and alcohol consumption. Of all 34 MRSA species, 22 (64.7% samples were resistant to erythromycin, 17 (50.0% resistant to cefoxitin, 5 (14.7% resistant to mupirocin, 1 (2.9% resistant to vancomycin and 1 (2.9% resistant to linezolid. Conclusion: The results of the current study show that among hospitalized patients, there is resistance against methicillin. Since based on results of the study there is resistance against oxacillin and erythromycin in most cases, administering appropriate antibiotics have an important role in minimizing the resistance burden among bacterial species.

  13. Curcumin Reverse Methicillin Resistance in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Su-Hyun Mun

    2014-11-01

    Full Text Available Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM. We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD600 of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD and sodium azide (NaN3 were reduced to 94% and 55%, respectively. When peptidoglycan (PGN from S. aureus was combined with curcumin, PGN (0–125 μg/mL gradually blocked the antibacterial activity of curcumin (125 μg/mL; however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was

  14. Cytoplasmic peptidoglycan intermediate levels in Staphylococcus aureus.

    Science.gov (United States)

    Vemula, Harika; Ayon, Navid J; Gutheil, William G

    2016-02-01

    Intracellular cytoplasmic peptidoglycan (PG) intermediate levels were determined in Staphylococcus aureus during log-phase growth in enriched media. Levels of UDP-linked intermediates were quantitatively determined using ion pairing LC-MS/MS in negative mode, and amine intermediates were quantitatively determined stereospecifically as their Marfey's reagent derivatives in positive mode. Levels of UDP-linked intermediates in S. aureus varied from 1.4 μM for UDP-GlcNAc-Enolpyruvyate to 1200 μM for UDP-MurNAc. Levels of amine intermediates (L-Ala, D-Ala, D-Ala-D-Ala, L-Glu, D-Glu, and L-Lys) varied over a range of from 860 μM for D-Ala-D-Ala to 30-260 mM for the others. Total PG was determined from the D-Glu content of isolated PG, and used to estimate the rate of PG synthesis (in terms of cytoplasmic metabolite flux) as 690 μM/min. The total UDP-linked intermediates pool (2490 μM) is therefore sufficient to sustain growth for 3.6 min. Comparison of UDP-linked metabolite levels with published pathway enzyme characteristics demonstrates that enzymes on the UDP-branch range from >80% saturation for MurA, Z, and C, to <5% saturation for MurB. Metabolite levels were compared with literature values for Escherichia coli, with the major difference in UDP-intermediates being the level of UDP-MurNAc, which was high in S. aureus (1200 μM) and low in E. coli (45 μM). Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  15. Crystal structure of Staphylococcus aureus Cas9

    OpenAIRE

    Nishimasu, Hiroshi; Cong, Le; Yan, Winston X.; Ran, F. Ann; Zetsche, Bernd; Li, Yinqing; Kurabayashi, Arisa; Ishitani, Ryuichiro; Zhang, Feng; Nureki, Osamu

    2015-01-01

    The RNA-guided DNA endonuclease Cas9 cleaves double-stranded DNA targets with a protospacer adjacent motif (PAM) and complementarity to the guide RNA. Recently, we harnessed Staphylococcus aureus Cas9 (SaCas9), which is significantly smaller than Streptococcus pyogenes Cas9 (SpCas9), to facilitate efficient in vivo genome editing. Here, we report the crystal structures of SaCas9 in complex with a single guide RNA (sgRNA) and its double-stranded DNA targets, containing the 5′-TTGAAT-3′ PAM and...

  16. Subinhibitory Concentrations of Thymol Reduce Enterotoxins A and B and α-Hemolysin Production in Staphylococcus aureus Isolates

    Science.gov (United States)

    Xiang, Hua; Feng, Haihua; Jiang, Youshuai; Xia, Lijie; Dong, Jing; Lu, Jing; Yu, Lu; Deng, Xuming

    2010-01-01

    Background Targeting bacterial virulence factors is now gaining interest as an alternative strategy to develop new types of anti-infective agents. It has been shown that thymol, when used at low concentrations, can inhibit the TSST-1 secretion in Staphylococcus aureus. However, there are no data on the effect of thymol on the production of other exotoxins (e.g., α-hemolysin and enterotoxins) by S. aureus. Methodology/Principal Findings Secretion of α-hemolysin, SEA and SEB in both methicillin-sensitive and methicillin-resistant S. aureus isolates cultured with graded subinhibitory concentrations of thymol was detected by immunoblot analysis. Hemolysin and tumor necrosis factor (TNF) release assays were performed to elucidate the biological relevance of changes in α-hemolysin, SEA and SEB secretion induced by thymol. In addition, the influence of thymol on the transcription of hla, sea, and seb (the genes encoding α-hemolysin, SEA and SEB, respectively) was analyzed by quantitative RT-PCR. Thymol inhibited transcription of hla, sea and seb in S. aureus, resulting in a reduction of α-hemolysin, SEA and SEB secretion and, thus, a reduction in hemolytic and TNF-inducing activities. Conclusions/Significance Subinhibitory concentrations of thymol decreased the production of α-hemolysin, SEA and SEB in both MSSA and MRSA in a dose-dependent manner. These data suggest that thymol may be useful for the treatment of S. aureus infections when used in combination with β-lactams and glycopeptide antibiotics, which induce expression of α-hemolysin and enterotoxins at subinhibitory concentrations. Furthermore, the structure of thymol may potentially be used as a basic structure for development of drugs aimed against these bacterial virulence factors. PMID:20305813

  17. Subinhibitory concentrations of thymol reduce enterotoxins A and B and alpha-hemolysin production in Staphylococcus aureus isolates.

    Science.gov (United States)

    Qiu, Jiazhang; Wang, Dacheng; Xiang, Hua; Feng, Haihua; Jiang, Youshuai; Xia, Lijie; Dong, Jing; Lu, Jing; Yu, Lu; Deng, Xuming

    2010-03-17

    Targeting bacterial virulence factors is now gaining interest as an alternative strategy to develop new types of anti-infective agents. It has been shown that thymol, when used at low concentrations, can inhibit the TSST-1 secretion in Staphylococcus aureus. However, there are no data on the effect of thymol on the production of other exotoxins (e.g., alpha-hemolysin and enterotoxins) by S. aureus. Secretion of alpha-hemolysin, SEA and SEB in both methicillin-sensitive and methicillin-resistant S. aureus isolates cultured with graded subinhibitory concentrations of thymol was detected by immunoblot analysis. Hemolysin and tumor necrosis factor (TNF) release assays were performed to elucidate the biological relevance of changes in alpha-hemolysin, SEA and SEB secretion induced by thymol. In addition, the influence of thymol on the transcription of hla, sea, and seb (the genes encoding alpha-hemolysin, SEA and SEB, respectively) was analyzed by quantitative RT-PCR. Thymol inhibited transcription of hla, sea and seb in S. aureus, resulting in a reduction of alpha-hemolysin, SEA and SEB secretion and, thus, a reduction in hemolytic and TNF-inducing activities. Subinhibitory concentrations of thymol decreased the production of alpha-hemolysin, SEA and SEB in both MSSA and MRSA in a dose-dependent manner. These data suggest that thymol may be useful for the treatment of S. aureus infections when used in combination with beta-lactams and glycopeptide antibiotics, which induce expression of alpha-hemolysin and enterotoxins at subinhibitory concentrations. Furthermore, the structure of thymol may potentially be used as a basic structure for development of drugs aimed against these bacterial virulence factors.

  18. Subinhibitory concentrations of thymol reduce enterotoxins A and B and alpha-hemolysin production in Staphylococcus aureus isolates.

    Directory of Open Access Journals (Sweden)

    Jiazhang Qiu

    Full Text Available BACKGROUND: Targeting bacterial virulence factors is now gaining interest as an alternative strategy to develop new types of anti-infective agents. It has been shown that thymol, when used at low concentrations, can inhibit the TSST-1 secretion in Staphylococcus aureus. However, there are no data on the effect of thymol on the production of other exotoxins (e.g., alpha-hemolysin and enterotoxins by S. aureus. METHODOLOGY/PRINCIPAL FINDINGS: Secretion of alpha-hemolysin, SEA and SEB in both methicillin-sensitive and methicillin-resistant S. aureus isolates cultured with graded subinhibitory concentrations of thymol was detected by immunoblot analysis. Hemolysin and tumor necrosis factor (TNF release assays were performed to elucidate the biological relevance of changes in alpha-hemolysin, SEA and SEB secretion induced by thymol. In addition, the influence of thymol on the transcription of hla, sea, and seb (the genes encoding alpha-hemolysin, SEA and SEB, respectively was analyzed by quantitative RT-PCR. Thymol inhibited transcription of hla, sea and seb in S. aureus, resulting in a reduction of alpha-hemolysin, SEA and SEB secretion and, thus, a reduction in hemolytic and TNF-inducing activities. CONCLUSIONS/SIGNIFICANCE: Subinhibitory concentrations of thymol decreased the production of alpha-hemolysin, SEA and SEB in both MSSA and MRSA in a dose-dependent manner. These data suggest that thymol may be useful for the treatment of S. aureus infections when used in combination with beta-lactams and glycopeptide antibiotics, which induce expression of alpha-hemolysin and enterotoxins at subinhibitory concentrations. Furthermore, the structure of thymol may potentially be used as a basic structure for development of drugs aimed against these bacterial virulence factors.

  19. A cohort study of the Copenhagen CF Centre eradication strategy against Staphylococcus aureus in patients with CF

    DEFF Research Database (Denmark)

    Dalbøge, Christina Schjellerup; Pressler, Tacjana; Høiby, Niels

    2013-01-01

    Staphylococcus aureus is an important pathogen in CF. Centre prevalence of intermittent colonization and chronic S. aureus infections and the effectiveness of an anti-S. aureus eradication strategy was assessed.......Staphylococcus aureus is an important pathogen in CF. Centre prevalence of intermittent colonization and chronic S. aureus infections and the effectiveness of an anti-S. aureus eradication strategy was assessed....

  20. Staphylococcus aureus bacteriuria as a prognosticator for outcome of Staphylococcus aureus bacteremia: a case-control study

    Directory of Open Access Journals (Sweden)

    Weinstein Robert A

    2010-07-01

    Full Text Available Abstract Background When Staphylococcus aureus is isolated in urine, it is thought to usually represent hematogenous spread. Because such spread might have special clinical significance, we evaluated predictors and outcomes of S. aureus bacteriuria among patients with S. aureus bacteremia. Methods A case-control study was performed at John H. Stroger Jr. Hospital of Cook County among adult inpatients during January 2002-December 2006. Cases and controls had positive and negative urine cultures, respectively, for S. aureus, within 72 hours of positive blood culture for S. aureus. Controls were sampled randomly in a 1:4 ratio. Univariate and multivariable logistic regression analyses were done. Results Overall, 59% of patients were African-American, 12% died, 56% of infections had community-onset infections, and 58% were infected with methicillin-susceptible S. aureus (MSSA. Among 61 cases and 247 controls, predictors of S. aureus bacteriuria on multivariate analysis were urological surgery (OR = 3.4, p = 0.06 and genitourinary infection (OR = 9.2, p = 0.002. Among patients who died, there were significantly more patients with bacteriuria than among patients who survived (39% vs. 17%; p = 0.002. In multiple Cox regression analysis, death risks in bacteremic patients were bacteriuria (hazard ratio 2.9, CI 1.4-5.9, p = 0.004, bladder catheter use (2.0, 1.0-4.0, p = 0.06, and Charlson score (1.1, 1.1-1.3, p = 0.02. Neither length of stay nor methicillin-resistant Staphylococcus aureus (MRSA infection was a predictor of S. aureus bacteriuria or death. Conclusions Among patients with S. aureus bacteremia, those with S. aureus bacteriuria had 3-fold higher mortality than those without bacteriuria, even after adjustment for comorbidities. Bacteriuria may identify patients with more severe bacteremia, who are at risk of worse outcomes.

  1. Nasal carriage of Staphylococcus aureus among healthy adults.

    Science.gov (United States)

    Choi, Chong Seng; Yin, Chow Suet; Bakar, Afra Abu; Sakewi, Zamberi; Naing, Nyi Nyi; Jamal, Farida; Othman, Norlijah

    2006-12-01

    Data on the carriage rate and antibiotic sensitivity pattern of Staphylococcus aureus strains prevalent in the community are not available for many developing countries including Malaysia. To estimate the extent of community S. aureus transmission, in particular methicillin-resistant S. aureus (MRSA), the prevalence of S. aureus nasal colonization in a population of healthy adults was determined. Factors associated with S. aureus nasal carriage and antibiotic sensitivity patterns of the isolates were also analyzed. A cross-sectional study involving 346 adults was conducted. Nasal swabs were examined for the presence of S. aureus. Epidemiological information concerning risk factors for nasal carriage was also obtained. Antibiotic susceptibility testing was performed using the disk diffusion method according to the National Committee for Clinical Laboratory Standards guidelines. MRSA strains isolated were further subjected to pulse-field gel electrophoresis analysis. The prevalence of S. aureus nasal carriage was 23.4%. The findings also revealed that ex-smokers (95% confidence interval [CI] 1.08-6.32, p=0.033) and oral contraceptive users (95% CI 1.12-21.67, p=0.035) were more likely to harbor S. aureus. One person was colonized with MRSA, which was different from the hospital strain. MRSA nasal colonization was found to be low outside of the health care environment. Smokers and oral contraceptive users have high nasal carrier rates.

  2. Beta Lactamase production by Staphylococcus aureus from children ...

    African Journals Online (AJOL)

    Isolates of Staphylococcus aureus from children aged 5 years and below with sporadic diarrhoea were tested for their ability to produce beta-lactamase enzyme. Of the 95 isolates tested 79 (83.2%) were beta-lactamase-producing strains. The study confirms that majority of clinical isolates of S. aureus from diarrhoeic ...

  3. Staphylococcus aureus strategies to evade the host acquired immune response.

    Science.gov (United States)

    Goldmann, Oliver; Medina, Eva

    2017-09-15

    Staphylococcus aureus poses a significant public-health problem. Infection caused by S. aureus can manifest as acute or long-lasting persistent diseases that are often refractory to antibiotic and are associated with significant morbidity and mortality. To develop more effective strategies for preventing or treating these infections, it is crucial to understand why the immune response is incapable to eradicate the bacterium. When S. aureus first infect the host, there is a robust activation of the host innate immune responses. Generally, S. aureus can survive this initial interaction due to the expression of a wide array of virulence factors that interfere with the host innate immune defenses. After this initial interaction the acquired immune response is the arm of the host defenses that will try to clear the pathogen. However, S. aureus is capable of maintaining infection in the host even in the presence of a robust antigen-specific immune response. Thus, understanding the mechanisms underlying the ability of S. aureus to escape immune surveillance by the acquired immune response will help uncover potentially important targets for the development of immune-based adjunctive therapies and more efficient vaccines. There are several lines of evidence that lead us to believe that S. aureus can directly or indirectly disable the acquired immune response. This review will discuss the different immune evasion strategies used by S. aureus to modulate the different components of the acquired immune defenses. Copyright © 2017 Elsevier GmbH. All rights reserved.

  4. Intercenter reproducibility of binary typing for Staphylococcus aureus

    NARCIS (Netherlands)

    van Leeuwen, Willem B.; Snoeijers, Sandor; van der Werken-Libregts, Christel; Tuip, Anita; van der Zee, Anneke; Egberink, Diane; de Proost, Monique; Bik, Elisabeth; Lunter, Bjorn; Kluytmans, Jan; Gits, Etty; van Duyn, Inge; Heck, Max; van der Zwaluw, Kim; Wannet, Wim; Noordhoek, Gerda T.; Mulder, Sije; Renders, Nicole; Boers, Miranda; Zaat, Sebastiaan; van der Riet, Daniëlle; Kooistra, Mirjam; Talens, Adriaan; Dijkshoorn, Lenie; van der Reyden, Tanny; Veenendaal, Dick; Bakker, Nancy; Cookson, Barry; Lynch, Alisson; Witte, Wolfgang; Cuny, Christa; Blanc, Dominique; Vernez, Isabelle; Hryniewicz, Waleria; Fiett, Janusz; Struelens, Marc; Deplano, Ariane; Landegent, Jim; Verbrugh, Henri A.; van Belkum, Alex

    2002-01-01

    The reproducibility of the binary typing (BT) protocol developed for epidemiological typing of Staphylococcus aureus was analyzed in a biphasic multicenter study. In a Dutch multicenter pilot study, 10 genetically unique isolates of methicillin-resistant S. aureus (MRSA) were characterized by the BT

  5. Duplex Identification of Staphylococcus aureus by Aptamer and Gold Nanoparticles.

    Science.gov (United States)

    Chang, Tianjun; Wang, Libo; Zhao, Kexu; Ge, Yu; He, Meng; Li, Gang

    2016-06-01

    Staphylococcus aureus is the top common pathogen causing infections and food poisoning. Identification of S. aureus is crucial for the disease diagnosis and regulation of food hygiene. Herein, we report an aptamer-AuNPs based method for duplex identification of S. aureus. Using AuNPs as an indicator, SA23, an aptamer against S. aureus, can well identify its target from Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa. Furthermore, we find citrate-coated AuNPs can strongly bind to S. aureus, but not bind to Salmonella enterica and Proteus mirabilis, which leads to different color changes in salt solution. This colorimetric response is capable of distinguishing S. aureus from S. enteritidis and P. mirabilis. Thus, using the aptasensor and AuNPs together, S. aureus can be accurately identified from the common pathogens. This duplex identification system is a promising platform for simple visual identification of S. aureus. Additionally, in the aptasensing process, bacteria are incubated with aptamers and then be removed before the aptamers adding to AuNPs, which may avoid the interactions between bacteria and AuNPs. This strategy can be potentially applied in principle to detect other cells by AuNPs-based aptasensors.

  6. Heterogeneity of the humoral immune response following Staphylococcus aureus bacteremia

    NARCIS (Netherlands)

    N.J. Verkaik (Nelianne); H.A.M. Boelens (Hélène); C.P. de Vogel (Corné); M. Tavakol (Mehri); L.G.M. Bode (Lonneke); H.A. Verbrugh (Henri); A.F. van Belkum (Alex); W.J.B. van Wamel (Willem)

    2010-01-01

    textabstractExpanding knowledge on the humoral immune response in Staphylococcus aureus-infected patients is a mandatory step in the development of vaccines and immunotherapies. Here, we present novel insights into the antibody responses following S. aureus bacteremia. Fifteen bacteremic patients

  7. Detection of some virulence factors in Staphylococcus aureus ...

    African Journals Online (AJOL)

    pathogens that can cause mastitis, Staphylococcus aureus is probably the most lethal agent because it causes chronic and deep infection in the mammary glands that is extremely difficult to be cured. The present study was to detect some of the virulence factors in the S. aureus isolated from 360 mastitis milk samples in ...

  8. Staphylococcus aureus from the German general population is highly diverse

    NARCIS (Netherlands)

    Becker, Karsten; Schaumburg, Frieder; Fegeler, Christian; Friedrich, Alexander W.; Kock, Robin

    Objectives: This prospective cohort study evaluates colonization dynamics and molecular characteristics of methicillin-susceptible and - resistant Staphylococcus aureus (MSSA/MRSA) in a German general population. Methods: Nasal swabs of 1878 non-hospitalized adults were screened for S. aureus.

  9. Invasive Staphylococcus aureus infection in an African adolescent ...

    African Journals Online (AJOL)

    Staphylococcus aureus remains an important cause of mortality, in the community and health care set-ups. S. aureus strains with genes encoding lethal toxins and culture negative sepsis augment the diagnostic challenge in resource limited settings. With a growing rate of resistance to the causative bacteria and atypical ...

  10. Staphylococcus aureus bacteraemia in children: a formidable foe

    African Journals Online (AJOL)

    Staphylococcus aureus remains one of the most common causes of bacteraemia in children. In order to evade and overcome the immune responses of its host and any antimicrobial therapies aimed at destroying it, this organism, through various mechanisms, continues to evolve. Staphylococcus aureus bacteraemia is a ...

  11. Identification of the ClpX Regulon in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Jelsbak, Lotte; Thomsen, Line Elnif; Ingmer, Hanne

    Staphyloccous aureus is a major human pathogen capable of causing a wide spectrum of infections ranging from superficial wound infections to life-threatening endocarditis and toxic shock syndrome. Essential for S. aureus virulence is a large number of cell-surface-associated proteins and secreted...

  12. Nasal carriage of multi-drug resistant Staphylococcus aureus in ...

    African Journals Online (AJOL)

    Background: Nasal Staphylococcus aureus is a major source of community and hospital associated staphylococcal infections. This study determined the prevalence of nasal S. aureus isolates and investigated their antimicrobial resistance profile in healthy volunteers. Methods: Nasal specimens of healthy volunteers in ...

  13. Detection and identification of Staphylococcus aureus in raw milk by ...

    African Journals Online (AJOL)

    Staphylococcus aureus causes foodborne diseases if consumed in contaminated milk products. Rapid detection and characterization of foodborne pathogen S. aureus is crucial for epidemiological investigations and food safety surveillance. It is still a challenge to detect and identify bacterial pathogens quickly and ...

  14. Toxins and adhesion factors associated with Staphylococcus aureus ...

    African Journals Online (AJOL)

    Staphylococcus aureus is a causative agent of acute and infectious diarrhoea. In Africa, there is no sufficient information on the virulence and the degree of factors produced by its diarrhoea-isolated strains. Clinical features and virulence factors produced by S. aureus isolated from diarrhoeal-patients admitted at the ...

  15. Staphylococcus aureus ST398 from slaughter pigs in northeast China

    NARCIS (Netherlands)

    Yan, Xiaomei; Yu, Xiaojie; Tao, Xiaoxia; Zhang, Jianfeng; Zhang, Binghua; Dong, Rui; Xue, Chengyu; Grundmann, Hajo; Zhang, Jianzhong

    To describe the prevalence and population structure of Staphylococcus aureus bacteria that colonize pigs at slaughterhouses in northeastern China, nose swabs were collected from pigs in two slaughterhouses in Harbin, Heilongjiang Province, China in 2009.S. aureus isolates were characterized by

  16. Prevalence of Methicillin-Resistant Staphylococcus aureus among ...

    African Journals Online (AJOL)

    Purpose: To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in apparently healthy ... Keywords: Methicillin-resistant Staphylococcus aureus, Nasal swabs, Multidrug resistance, Rational chemotherapy .... Figure 2: Antibiotic resistance profile of the MRSA isolates. Key: AM-amoxicillin ...

  17. Pneumonia and new methicillin-resistant Staphylococcus aureus clone.

    NARCIS (Netherlands)

    Garnier, Fabien; Tristan, Anne; François, Bruno; Etienne, Jerome; Delage-Corre, Manuella; Martin, Christian; Liassine, Nadia; Wannet, Wim; Denis, François; Ploy, Marie-Cécile

    2006-01-01

    Necrotizing pneumonia caused by Staphylococcus aureus strains carrying the Panton-Valentin leukocidin gene is a newly described disease entity. We report a new fatal case of necrotizing pneumonia. An S. aureus strain with an agr1 allele and of a new sequence type 377 was recovered, representing a

  18. Nasal carriage of methicilli-resistant staphylococcus aureus with ...

    African Journals Online (AJOL)

    Staphylococcus aureus isolates were collected from anterior nares of fifty healthy adults in Zaria and their antibiotic susceptibility patterns determined. Seventy-two percent (72%) of the isolates were methicillin-resistant S. aureus, while 20% were methicillin-susceptible. The isolates were generally resistant to multiple ...

  19. Prevalence of Methicillin–Resistant Staphylococcus aureus (MRSA ...

    African Journals Online (AJOL)

    Staphylococcus aureus is a major bacterial pathogen that causes different community and hospital-acquired infections. Over time, strains of S. aureus have become resistant to different antibiotics including penicillinase-resistant penicillins. Having data on the local antimicrobial susceptibility pattern of this pathogen is ...

  20. Detection of some virulence factors in Staphylococcus aureus ...

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... present study was to detect some of the virulence factors in the S. aureus isolated from 360 mastitis milk samples in ... Key words: Bovine mastitis, Staphylococcus aureus, virulence factors, polymerase chain reaction (PCR), Iran. INTRODUCTION ..... staphylococcal hemolysins. Zentralbl Bakteriol Orig A.

  1. Virulence potential of Staphylococcus aureus isolates from Buruli ulcer patients

    NARCIS (Netherlands)

    Amissah, Nana Ama; Chlebowicz, Monika A.; Ablordey, Anthony; Tetteh, Caitlin S.; Prah, Isaac; van der Werf, Tjip S.; Friedrich, Alex W.; van Dijl, Jan Maarten; Stienstra, Ymkje; Rossen, John W.

    Buruli ulcer (BU) is a necrotizing infection of the skin and subcutaneous tissue caused by Mycobacterium ulcerans. BU wounds may also be colonized with other microorganisms including Staphylococcus aureus. This study aimed to characterize the virulence factors of S. aureus isolated from BU patients.

  2. Staphylococcus aureus in mastitic crossbreed cows and its ...

    African Journals Online (AJOL)

    and its associated risk factors in Addis Ababa City,. Ethiopia ... and wide spread livestock diseases (Mohammed Ahmed et al., 2004). Mastitis .... Legesse Garedew et al.,. Table 2: Risk factors associated with the occurrence of Staphylococcus aureus in mastitic cows. Risk factor. Total animals S. aureus positives. X2 p-value.

  3. Daya Hambat Ekstrak Aloe Vera terhadap pertumbuhan Staphylococcus Aureus

    OpenAIRE

    Rahmat, drg.Sp,Pros

    2011-01-01

    Dari hasil penelitian , maka dapat disimpulkan bahwa ekstrak Aloe Vera dapat menghambat pertumbuhan bakteri Stafhylococcus aureus, dan kadar hambat minimal ekstrak Aloe Vera adalah pada konsentrasi 25%. Tujuan Penelitan Ini adalah untuk mengetahui efektifitas ekstrak Aloe vera dalam menghambat pertumbuhan bakteri Stafhylococcus aureus dan daya hambat menimal, (DHM) terhadap pertumbuhan bakteri tersebut. Metode yang digunakan adalah pertumbuhan ekstrak Aloe vera, penegnceran ekstrak , pemur...

  4. Maternal-neonatal outcome with Staphylococcus aureus rectovaginal colonization.

    Science.gov (United States)

    Ghanim, Nibal; Alchyib, Omrou; Morrish, Donald; Tompkins, David; Julliard, Kell; Visconti, Ernest; Hoskins, Iffath A

    2011-01-01

    To estimate prevalence of rectovaginal colonization by Staphylococcus aureus among pregnant women with group B streptococcus (GBS) screening results and its association with maternal and infant outcomes. Cultures that detected both group B streptococcus (GBS) and S. aureus were obtained at > or = 35 weeks of gestation. Computerized database search and chart review determined invasive neonatal infection and maternal outcomes at the time of delivery through 6 months postpartum. A total of 6,626 GBS screening cultures met study criteria, and 769 (11.6%) GBS isolates and 67 (1.0%) S. aureus were identified. No maternal S. aureus-related outcomes were found. The rate of maternal methicillin-resistant S. aureus colonization was 0.1% (7 in 6,626). GBS-positive patients were twice as likely to be colonized with methicillin-susceptible S. aureus than GBS-negative patients. GBS-positive culture rates differed significantly by primary language: Spanish 10.0%, English 13.7%, Russian 26.9%, Cantonese 13.2%, Mandarin 11.5%, Arabic 15.9%, and other 17.8%. In our population, S. aureus colonization percentage (1.0%) was lower than the 7.5-8.2% reported by other medical centers, as was overall GBS carriage rate. S. aureus did not predispose to maternal or infant morbidity or mortality up to 6 months postpartum.

  5. Carriage of Staphylococcus aureus on armpits of secondary school ...

    African Journals Online (AJOL)

    A study of carriage of Staphylococcus aureus on armpits and factors affecting it was carried out on 50 students from Community Secondary School, Oroworokwu, Port Harcourt and 50 University of Port Harcourt students. Samples were inoculated onto mannitol salt agar plates and coagulate positive S. aureus isolates were ...

  6. Assessment of virulence diversity of methicillin-resistant Staphylococcus aureus strains with a Drosophila melanogaster infection model

    Directory of Open Access Journals (Sweden)

    Wu Kaiyu

    2012-11-01

    Full Text Available Abstract Background Staphylococcus aureus strains with distinct genetic backgrounds have shown different virulence in animal models as well as associations with different clinical outcomes, such as causing infection in the hospital or the community. With S. aureus strains carrying diverse genetic backgrounds that have been demonstrated by gene typing and genomic sequences, it is difficult to compare these strains using mammalian models. Invertebrate host models provide a useful alternative approach for studying bacterial pathogenesis in mammals since they have conserved innate immune systems of biological defense. Here, we employed Drosophila melanogaster as a host model for studying the virulence of S. aureus strains. Results Community-associated methicillin-resistant S. aureus (CA-MRSA strains USA300, USA400 and CMRSA2 were more virulent than a hospital-associated (HA-MRSA strain (CMRSA6 and a colonization strain (M92 in the D. melanogaster model. These results correlate with bacterial virulence in the Caenorhabditis elegans host model as well as human clinical data. Moreover, MRSA killing activities in the D. melanogaster model are associated with bacterial replication within the flies. Different MRSA strains induced similar host responses in D. melanogaster, but demonstrated differential expression of common bacterial virulence factors, which may account for the different killing activities in the model. In addition, hemolysin α, an important virulence factor produced by S. aureus in human infections is postulated to play a role in the fly killing. Conclusions Our results demonstrate that the D. melanogaster model is potentially useful for studying S. aureus pathogenicity. Different MRSA strains demonstrated diverse virulence in the D. melanogaster model, which may be the result of differing expression of bacterial virulence factors in vivo.

  7. Nasal carriage of methicillin resistant Staphylococcus aureus among health care workers at a tertiary care hospital in Western Nepal.

    Science.gov (United States)

    Khanal, Rita; Sah, Prakash; Lamichhane, Pramila; Lamsal, Apsana; Upadhaya, Sweety; Pahwa, Vijay Kumar

    2015-01-01

    Staphylococcus aureus is a frequent cause of infections in both the community and hospital. Methicillin-resistant Staphylococcus aureus continues to be an important nosocomial pathogen and infections are often difficult to manage due to its resistance to multiple antibiotics. Healthcare workers are important source of nosocomial transmission of MRSA. This study aimed to determine the nasal carriage rate of S. aureus and MRSA among healthcare workers at Universal College of Medical Sciences and Teaching Hospital, Nepal and to determine antibiotic susceptibility pattern of the isolates. A cross-sectional study involving 204 healthcare workers was conducted. Nasal swabs were collected and cultured on Mannitol salt agar. Mannitol fermenting colonies which were gram positive cocci, catalase positive and coagulase positive were identified as S. aureus. Antibiotic susceptibility test was performed by modified Kirby-Bauer disc diffusion method. Methicillin resistance was detected using cefoxitin disc diffusion method. Of 204 healthcare workers, 32 (15.7 %) were nasal carriers of S. aureus and among them 7 (21.9 %) were carrier of MRSA. Overall nasal carriage rate of MRSA was 3.4 % (7/204). Highest MRSA nasal carriage rate of 7.8 % (4/51) was found among nurses. Healthcare workers of both surgical wards and operating room accounted for 28.6 % (2/7) of MRSA carriers each. Among MRSA isolates inducible clindamycin resistance was observed in 66.7 % (2/3) of erythromycin resistant isolates. High nasal carriage of S. aureus and MRSA among healthcare workers (especially in surgery ward and operating room) necessitates improved infection control measures to be employed to control MRSA transmission in our setting.

  8. Selective biosensing of Staphylococcus aureus using chitosan quantum dots

    Science.gov (United States)

    Abdelhamid, Hani Nasser; Wu, Hui-Fen

    2018-01-01

    Selective biosensing of Staphylococcus aureus (S. aureus) using chitosan modified quantum dots (CTS@CdS QDs) in the presence of hydrogen peroxide is reported. The method is based on the intrinsic positive catalase activity of S. aureus. CTS@CdS quantum dots provide high dispersion in aqueous media with high fluorescence emission. Staphylococcus aureus causes a selective quenching of the fluorescence emission of CTS@CdS QDs in the presence of H2O2 compared to other pathogens such as Escherichia coli and Pseudomonas aeruginosa. The intrinsic enzymatic character of S. aureus (catalase positive) offers selective and fast biosensing. The present method is highly selective for positive catalase species and requires no expensive reagents such as antibodies, aptamers or microbeads. It could be extended for other species that are positive catalase.

  9. Staphylococcus aureus vs. Osteoblast: Relationship and Consequences in Osteomyelitis

    Science.gov (United States)

    Josse, Jérôme; Velard, Frédéric; Gangloff, Sophie C.

    2015-01-01

    Bone cells, namely osteoblasts and osteoclasts work in concert and are responsible for bone extracellular matrix formation and resorption. This homeostasis is, in part, altered during infections by Staphylococcus aureus through the induction of various responses from the osteoblasts. This includes the over-production of chemokines, cytokines and growth factors, thus suggesting a role for these cells in both innate and adaptive immunity. S. aureus decreases the activity and viability of osteoblasts, by induction of apoptosis-dependent and independent mechanisms. The tight relationship between osteoclasts and osteoblasts is also modulated by S. aureus infection. The present review provides a survey of the relevant literature discussing the important aspects of S. aureus and osteoblast interaction as well as the ability for antimicrobial peptides to kill intra-osteoblastic S. aureus, hence emphasizing the necessity for new anti-infectious therapeutics. PMID:26636047

  10. Characterization of methicillin-resistant Staphylococcus aureus Sequence Type 398

    DEFF Research Database (Denmark)

    Christiansen, Mette Theilgaard

    . aureus and methicillin-resistant Staphylococcus aureus (MRSA) have been associated with hospitals, but during the past decades MRSA has emerged in the community and now a new branch of MRSA has been found in association with livestock (LA-MRSA). A specific lineage (multilocus sequence type 398 (ST398......Staphylococcus aureus is an opportunistic pathogen that colonizes the nares and skin surfaces of several animal species, including man. S. aureus can cause a wide variety of infections ranging from superficial soft tissue and skin infections to severe and deadly systemic infections. Traditionally S...... for LA-MRSA ST398 survival on porcine skin and nasal epithelium ex vivo were identified. These genes could represent targets for de-colonization, which could help prevent further spread and adaption of LA-MRSA ST398. Manuscript III describes the construction of the S. aureus VirulenceFinder database...

  11. Rapid Identification of Staphylococcus aureus Directly from Bactec Blood Culture Broth by the BinaxNOW S. aureus Test

    OpenAIRE

    Qian, Qinfang; Eichelberger, Karen; Kirby, James E.

    2014-01-01

    The BinaxNOW Staphylococcus aureus testing showed sensitivity, specificity, and positive and negative predicative values of 97.6%, 100%, 100%, and 98.4%, respectively, for identification of S. aureus from Bactec blood culture broth. Importantly, the test performed equally well on aerobic and anaerobic culture broth.

  12. Nasal Staphylococcus aureus and methicillin-resistant Staphylococcus aureus carriage among college student athletes in northern Taiwan

    Directory of Open Access Journals (Sweden)

    Hong-Kai Wang

    2017-08-01

    Full Text Available Of 259 college students in northern Taiwan surveyed, nasal carriage rate of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA was 22.4% and 1.54%, respectively and no significant difference was found between athlete students and non-athlete students. Three of four MRSA isolates belonged to sequence type 59, the endemic community clone.

  13. Low-shear modelled microgravity alters expression of virulence determinants of Staphylococcus aureus

    Science.gov (United States)

    Rosado, Helena; Doyle, Marie; Hinds, Jason; Taylor, Peter W.

    2010-02-01

    Microbiological monitoring of air and surfaces within the ISS indicate that bacteria of the genus Staphylococcus are found with high frequency. Staphylococcus aureus, an opportunistic pathogen with the capacity to cause severe debilitating infection, constitutes a significant proportion of these isolates. Experiments conducted during short-term flight suggest that growth in microgravity leads to increases in bacterial antibiotic resistance and to cell wall changes. Growth under low-shear modelled microgravity (LSMMG) indicated that a reduced gravitational field acts as an environmental signal for expression of enhanced bacterial virulence in gram-negative pathogens. We therefore examined the effect of simulated microgravity on parameters of antibiotic susceptibility and virulence in methicillin-susceptible S. aureus isolates RF1, RF6 and RF11; these strains were grown in a high aspect ratio vessel under LSMMG and compared with cells grown under normal gravity (NG). There were no significant differences in antibiotic susceptibility of staphylococci grown under LSMMG compared to NG. LSMMG-induced reductions in synthesis of the pigment staphyloxanthin and the major virulence determinant α-toxin were noted. Significant changes in global gene expression were identified by DNA microarray analysis; with isolate RF6, the expression of hla and genes of the regulatory system saeR/saeS were reduced approximately two-fold. These data provide strong evidence that growth of S. aureus under modelled microgravity leads to a reduction in expression of virulence determinants.

  14. Evolution in Fast Forward: a Potential Role for Mutators in Accelerating Staphylococcus aureus Pathoadaptation

    Science.gov (United States)

    Canfield, Gregory S.; Schwingel, Johanna M.; Foley, Matthew H.; Vore, Kelly L.; Boonanantanasarn, Kanitsak; Gill, Ann L.; Sutton, Mark D.

    2013-01-01

    Pathogen evolution and subsequent phenotypic heterogeneity during chronic infection are proposed to enhance Staphylococcus aureus survival during human infection. We tested this theory by genetically and phenotypically characterizing strains with mutations constructed in the mismatch repair (MMR) and oxidized guanine (GO) system, termed mutators, which exhibit increased spontaneous-mutation frequencies. Analysis of these mutators revealed not only strain-dependent increases in the spontaneous-mutation frequency but also shifts in mutational type and hot spots consistent with loss of GO or MMR functions. Although the GO and MMR systems are relied upon in some bacterial species to prevent reactive oxygen species-induced DNA damage, no deficit in hydrogen peroxide sensitivity was found when either of these DNA repair pathways was lost in S. aureus. To gain insight into the contribution of increased mutation supply to S. aureus pathoadaptation, we measured the rate of α-hemolysin and staphyloxanthin inactivation during serial passage. Detection of increased rates of α-hemolysin and staphyloxanthin inactivation in GO and MMR mutants suggests that these strains are capable of modifying virulence phenotypes implicated in mediating infection. Accelerated derivation of altered virulence phenotypes, combined with the absence of increased ROS sensitivity, highlights the potential of mutators to drive pathoadaptation in the host and serve as catalysts for persistent infections. PMID:23204459

  15. [Antibiotic susceptibility of community-acquired strains ofstaphylococcus aureus in Nouakchott Region (Mauritania)].

    Science.gov (United States)

    Salem, Mohamed Lemine Ould; Ghaber, Sidi Mohamed; Baba, Sidi El Wafi Ould; Maouloud, Mohamed Mahmoud Ould

    2016-01-01

    Staphilococcus aureus is a leading pathogen for humans causing a variety of infections such as skin, urinary tract and lung infections as well as sepsis. This study aims to evaluate the susceptibility of community-acquired strains of Staphylococcus aureus, isolated from various pathological products, compared with major antibiotics used in Nouakchott Region (Mauritania). We conducted a retrospective study of 281 strains of Staphylococcus aureus strains isolated from various pathological products from non-hospitalized patients in the National referral hospital laboratory and in two private laboratories in the city of Nouakchott between January 2014 and August 2015. Antibiotic sensitivity was determined by disk diffusion method using agar containing Mueller-Hinton medium according to CA-SFM's recommendations. The resistance rate to penicillin G was high (96-100%). Community-acquired MRSA rate was between 25 and 26% in suppurations, 34.3% in urine cultures and 28% in sperm cultures. Macrolide -Lincosamyne-streptogramins (MLS) resistance, giving rise to the phenotype MLSb inducible, was found in 6% of urinary strains and 27% of strains isolated from suppurations. The activity of aminoglycosides was variable, amikacin was active against all strains. Cotrimoxazole activity was low (77% had resistance) and no vancomycin resistance was reported. The activity of penicillin G against Staphylococcus aureusstrains isolated in Nouakchott region is almost zero and community-acquired MRSA rate is high, accounting for 34%. This could be explained by uncontrolled use of these molecules in our country.

  16. Antibacterial photodynamic therapy on Staphylococcus aureus and Pseudomonas aeruginosa in-vitro.

    Science.gov (United States)

    Thakuri, P S; Joshi, R; Basnet, S; Pandey, S; Taujale, S D; Mishra, N

    2011-12-01

    Photodynamic therapy (PDT) involves the use of drugs or dyes known as photosensitizers, and light source which induces cell death by the production of cytotoxic reactive oxygen species (ROS). This principle of cell death can be utilized to kill bacteria in vitro. We propose the use of blue light emitting diodes (LEDs) and Riboflavin as the light source and photosensitizer for in vitro killing of Staphylococcus aureus and Pseudomonas aeruginosa. Circularly arranged 65-blue LED array was designed as the light source to fit exactly over 7cm culture plate. Riboflavin having non-toxic properties and nucleic acid specificity was used as a photosensitizer. Clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa were used in our study. Effect of PDT on viability on these species of bacteria was compared with control samples that included: control untreated, control treated with light only and control treated with riboflavin only. Statistical analysis was done using one-way ANOVA test. PDT against Pseudomonas aeruginosa and Staphylococcus aureus was significantly (p blue LEDs and Riboflavin in PDT against these bacterial species has been successfully demonstrated in-vitro. Therefore, PDT has promising applications in the process of treating superficial wound infections.

  17. Is methicillin-resistant Staphylococcus aureus involved in community acquired skin and soft tissue infections?: Experience from a tertiary care centre in Mumbai

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    R S Phakade

    2012-01-01

    Full Text Available Background: To improve the empiric antimicrobial therapy of community-acquired (CA skin and soft tissue infections (SSTIs, it is necessary to generate data on the current spectrum and susceptibility profile of associated bacteria. CA methicillin-resistant Staphylococcus aureus (CA MRSA is increasingly being reported in SSTIs in India and globally. Aims: The present study was undertaken to determine the bacterial profile of CA-SSTIs, to know the contribution of MRSA in these infections, to determine inducible clindamycin resistance in S. aureus and to compare the resistance patterns of isolates from hospital-acquired (HA SSTIs. Materials and Methods: Eight hundred and twenty patients with CA SSTIs were prospectively studied. Pus samples were cultured and antimicrobial susceptibility pattern determined. Inducible clindamycin resistance was detected by D-test. Laboratory records were analyzed retrospectively to generate data on HA SSTIs. Results: 619 isolates were recovered in CA-SSTIs, of which S. aureus (73% and Streptococci (12% were the most common. Pseudomonas aeruginosa (28% and Acinetobacter spp (18% were the predominant HA-SSTI pathogens. Susceptibility of CA S. aureus to antibiotics tested was, penicillin (6%, co-trimoxazole (20%, ciprofloxacin (37%, cefazolin (100%, erythromycin (84%, clindamycin (97%, gentamicin (94% and fusidic acid (95%. No MRSA was found in CA SSTIs whereas 45% of HA S. aureus strains were methicillin-resistant. HA strains demonstrated significantly higher resistance as compared to their CA counterparts (P<0.001. D test was positive in 22% of CA S. aureus tested. Conclusions: In CA SSTIs, methicillin-susceptible S. aureus is the predominant pathogen. Penicillinase-resistant penicillins, clindamycin and erythromycin in that order can be used as suitable antimicrobials for empiric therapy. D test should be carried out routinely. No CA MRSA was detected in the present series.

  18. Staphylococcus aureus nasal carriage and patterns of antibiotic resistance in bacterial isolates from patients and staff in a dialysis center of southeast Iran.

    Science.gov (United States)

    Tashakori, Mahnaz; Mohseni Moghadam, Fateme; Ziasheikholeslami, Nazanin; Jafarpour, Parvin; Behsoun, Maryam; Hadavi, Maryam; Gomreei, Mohammadhossein

    2014-04-01

    Staphylococcus aureus is an important infection in hemodialysis patients. We studied the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) and its antibiotic resistance pattern in patients receiving hemodialysis as well as in dialysis unit staff. From June to September 2012, we evaluated 74 cases including 61 patients on hemodialysis and 13 dialysis unit staff. Nasal swabs were taken from all cases and were cultured on a blood medium agar. We identified S. aureus based on conventional laboratory methods. For antimicrobial resistance patterns, we used disk diffusion method. Oxacillin MIC, oxacillin and cefoxcitin disk diffusion methods were used for detection of MRSA. Disk approximation test (D-test) was applied for the frequency of erythromycin induced clindamycin resistance. S. aureus carrier state was determined in 12 of the 61 patients on hemodialysis (19.67%) and 5 of the 13 dialysis unit staffs (38.46%). In hemodialyzed patients, MRSA and MSSA carrier of S. aureus were 6.56% and 13.11%, respectively. All nasal carriage states in studied staffs were MSSA. All isolated S. aureus were found to be sensitive to vancomycin, teicoplanin, and rifampin. However, reduced sensitivity of MRSA isolates to other antibiotics was noted. Resistance frequencies to tested antibiotic was as follows: cefteriaxone and penicillin (100%), tetracycline and doxycilin (75%), gentamicin, cloxacillin, and cefazolin (50%), ciprofloxacin, trimethoprim-sulfamethoxazol, erythromycin, and clindamycin (25%). The resistance rate of isolated MSSA against tested antibiotics was lower than isolated MRSA. Inducible clindamycin resistance was shown in 25% of identified MRSA strains. S. aureus nasal carrier state was lower than former reports from other parts of Iran. The antibiotic resistance patterns also differed, perhaps due to different pattern of administering antibiotics at our hospital. Screening of these patients should be noted as a health priority and

  19. Influence of ciprofloxacin and vancomycin on mutation rate and transposition of IS256 in Staphylococcus aureus.

    Science.gov (United States)

    Nagel, Michael; Reuter, Tina; Jansen, Andrea; Szekat, Christiane; Bierbaum, Gabriele

    2011-03-01

    In Staphylococcus aureus, the development of intermediate resistance to vancomycin is due to an accumulation of mutations. To elucidate the mechanisms involved here, a standard laboratory strain (S. aureus HG001) and a clinical MRSA mutator strain (S. aureus SA1450/94, which is characterized by a spontaneous insertion of IS256 into the gene of the mismatch repair enzyme MutS) were incubated at subinhibitory concentrations of ciprofloxacin and vancomycin. Ciprofloxacin increased the mutation rates of both strains, but this effect was inhibited when the SOS response was blocked by the presence of a non-cleavable variant of the LexA repressor. In the presence of vancomycin, the mutation rate was slightly elevated in the mutator strain, and this increase also depended on the strain's ability to induce the SOS response. Furthermore, treatment with subinhibitory concentrations of both antibiotics resulted in an activation of transposition frequency of the insertion element IS256 in S. aureus HG001. Transposition was dependent on the presence of a functional transposase, and the activation of transposition depended on the presence of the functional phosphatase RsbU, which activates SigB transcription activity. An in silico analysis indicated a putative antisense sigma B promoter sequence within the transposase gene. Scrambling of this promoter resulted in an about 20-fold activation of transposition activity of IS256. These data indicate that sigma B is involved in the regulation of IS256 activity by generation of an antisense RNA. Copyright © 2010 Elsevier GmbH. All rights reserved.

  20. Opsonic and protective properties of antibodies raised to conjugate vaccines targeting six Staphylococcus aureus antigens.

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    Clarissa Pozzi

    Full Text Available Staphylococcus aureus is a major cause of nosocomial and community-acquired infections for which a vaccine is greatly desired. Antigens found on the S. aureus outer surface include the capsular polysaccharides (CP of serotype 5 (CP5 or 8 (CP8 and/or a second antigen, a β-(1→6-polymer of N-acetyl-D-glucosamine (PNAG. Antibodies specific for either CP or PNAG antigens have excellent in vitro opsonic killing activity (OPKA, but when mixed together have potent interference in OPKA and murine protection. To ascertain if this interference could be abrogated by using a synthetic non-acetylated oligosaccharide fragment of PNAG, 9GlcNH(2, in place of chemically partially deacetylated PNAG, three conjugate vaccines consisting of 9GlcNH(2 conjugated to a non-toxic mutant of alpha-hemolysin (Hla H35L, CP5 conjugated to clumping factor B (ClfB, or CP8 conjugated to iron-surface determinant B (IsdB were used separately to immunize rabbits. Opsonic antibodies mediating killing of multiple S. aureus strains were elicited for all three vaccines and showed carbohydrate antigen-specific reductions in the tissue bacterial burdens in animal models of S. aureus skin abscesses, pneumonia, and nasal colonization. Carrier-protein specific immunity was also shown to be effective in reducing bacterial levels in infected lungs and in nasal colonization. However, use of synthetic 9GlcNH(2 to induce antibody to PNAG did not overcome the interference in OPKA engendered when these were combined with antibody to either CP5 or CP8. Whereas each individual vaccine showed efficacy, combining antisera to CP antigens and PNAG still abrogated individual OPKA activities, indicating difficulty in achieving a multi-valent vaccine targeting both the CP and PNAG antigens.

  1. Ascorbic acid augments colony spreading by reducing biofilm formation of methicillin-resistantStaphylococcus aureus.

    Science.gov (United States)

    Ali Mirani, Zulfiqar; Khan, Muhammad Naseem; Siddiqui, Anila; Khan, Fouzia; Aziz, Mubashir; Naz, Shagufta; Ahmed, Ayaz; Khan, Seema Ismat

    2018-02-01

    Staphylococcus aureus is a Gram-positive pathogen, well known for its resistance and versatile lifestyle. Under unfavourable conditions, it adapts biofilm mode of growth. For staphylococcal biofilm formation, production of extracellular polymeric substances (EPS) is a pre-requisite, which is regulated by ica operon-encoded enzymes. This study was designed to know the impact of ascorbic acid on biofilm formation and colony spreading processes of S. aureus and MRSA. The isolates of methicillin-resistant S. aureus (MRSA) used in present study, were recovered from different food samples. Various selective and differential media were used for identification and confirmation of S. aureus . Agar dilution method was used for determination of oxacillin and ascorbic acid resistance level. MRSA isolates were re-confirmed by E-test and by amplification of mecA gene. Tube methods and Congo-Red agar were used to study biofilm formation processes. Gene expression studies were carried on real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The results revealed the presence of mecA gene belonging to SCC mecA type IV along with agr type II in the isolates. In vitro studies showed the sub-inhibitory concentration of oxacillin induced biofilm production. However, addition of sub-inhibitory dose of ascorbic acid was found to inhibit EPS production, biofilm formation and augment colony spreading on soft agar plates. The inhibition of biofilm formation and augmentation of colony spreading observed with ascorbic acid alone or in combination with oxacillin. Moreover, gene expression studies showed that ascorbic acid increases agr expression and decreases icaA gene expression. The present study concluded that ascorbic acid inhibits biofilm formation, promotes colony spreading and increases agr gene expression in MRSA.

  2. Generation of a vancomycin-intermediate Staphylococcus aureus (VISA) strain by two amino acid exchanges in VraS.

    Science.gov (United States)

    Berscheid, Anne; François, Patrice; Strittmatter, Axel; Gottschalk, Gerhard; Schrenzel, Jacques; Sass, Peter; Bierbaum, Gabriele

    2014-12-01

    Staphylococcus aureus is a notorious bacterial pathogen and antibiotic-resistant isolates complicate current treatment strategies. We characterized S. aureus VC40, a laboratory mutant that shows full resistance to glycopeptides (vancomycin and teicoplanin MICs ≥32 mg/L) and daptomycin (MIC = 4 mg/L), to gain deeper insights into the underlying resistance mechanisms. Genomics and transcriptomics were performed to characterize changes that might contribute to development of resistance. The mutations in vraS were reconstituted into a closely related parental background. In addition, antimicrobial susceptibility testing, growth analyses, transmission electron microscopy, lysostaphin-induced lysis and autolysis assays were performed to characterize the phenotype of resistant strains. Genome sequencing of strain VC40 revealed 79 mutations in 75 gene loci including genes encoding the histidine kinases VraS and WalK that control cell envelope-related processes. Transcriptomics indicated the increased expression of their respective regulons. Although not reaching the measured MIC for VC40, reconstitution of the L114S and D242G exchanges in VraS(VC40) into the susceptible parental background (S. aureus NCTC 8325) resulted in increased resistance to glycopeptides and daptomycin. The expression of VraS(VC40) led to increased transcription of the cell wall stress stimulon, a thickened cell wall, a decreased growth rate, reduced autolytic activity and increased resistance to lysostaphin-induced lysis in the generated mutant. We show that a double mutation of a single gene locus, namely vraS, is sufficient to convert the vancomycin-susceptible strain S. aureus NCTC 8325 into a vancomycin-intermediate S. aureus. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Staphylococcus aureus alpha-hemolysin activates the NLRP3-inflammasome in human and mouse monocytic cells.

    Directory of Open Access Journals (Sweden)

    Robin R Craven

    Full Text Available Community Acquired Methicillin Resistant Staphylococcus aureus (CA-MRSA causes severe necrotizing infections of the skin, soft tissues, and lungs. Staphylococcal alpha-hemolysin is an essential virulence factor in mouse models of CA-MRSA necrotizing pneumonia. S. aureus alpha-hemolysin has long been known to induce inflammatory signaling and cell death in host organisms, however the mechanism underlying these signaling events were not well understood. Using highly purified recombinant alpha-hemolysin, we now demonstrate that alpha-hemolysin activates the Nucleotide-binding domain and leucine-rich repeat containing gene family, pyrin domain containing 3 protein (NLRP3-inflammasome, a host inflammatory signaling complex involved in responses to pathogens and endogenous danger signals. Non-cytolytic mutant alpha-hemolysin molecules fail to elicit NLRP3-inflammasome signaling, demonstrating that the responses are not due to non-specific activation of this innate immune signaling system by bacterially derived proteins. In monocyte-derived cells from humans and mice, inflammasome assembly in response to alpha-hemolysin results in activation of the cysteine proteinase, caspase-1. We also show that inflammasome activation by alpha-hemolysin works in conjunction with signaling by other CA-MRSA-derived Pathogen Associated Molecular Patterns (PAMPs to induce secretion of pro-inflammatory cytokines IL-1beta and IL-18. Additionally, alpha-hemolysin induces cell death in these cells through an NLRP3-dependent program of cellular necrosis, resulting in the release of endogenous pro-inflammatory molecules, like the chromatin-associated protein, High-mobility group box 1 (HMGB1. These studies link the activity of a major S. aureus virulence factor to a specific host signaling pathway. The cellular events linked to inflammasome activity have clear relevance to the disease processes associated with CA-MRSA including tissue necrosis and inflammation.

  4. Staphylococcus aureus α-Hemolysin Activates the NLRP3-Inflammasome in Human and Mouse Monocytic Cells

    Science.gov (United States)

    Craven, Robin R.; Gao, Xi; Allen, Irving C.; Gris, Denis; Wardenburg, Juliane Bubeck; McElvania-TeKippe, Erin; Ting, Jenny P.; Duncan, Joseph A.

    2009-01-01

    Community Acquired Methicillin Resistant Staphylococcus aureus (CA-MRSA) causes severe necrotizing infections of the skin, soft tissues, and lungs. Staphylococcal α-hemolysin is an essential virulence factor in mouse models of CA-MRSA necrotizing pneumonia. S. aureus α-hemolysin has long been known to induce inflammatory signaling and cell death in host organisms, however the mechanism underlying these signaling events were not well understood. Using highly purified recombinant α-hemolysin, we now demonstrate that α-hemolysin activates the Nucleotide-binding domain and leucine-rich repeat containing gene family, pyrin domain containing 3 protein (NLRP3)-inflammasome, a host inflammatory signaling complex involved in responses to pathogens and endogenous danger signals. Non-cytolytic mutant α-hemolysin molecules fail to elicit NLRP3-inflammasome signaling, demonstrating that the responses are not due to non-specific activation of this innate immune signaling system by bacterially derived proteins. In monocyte-derived cells from humans and mice, inflammasome assembly in response to α-hemolysin results in activation of the cysteine proteinase, caspase-1. We also show that inflammasome activation by α-hemolysin works in conjunction with signaling by other CA-MRSA-derived Pathogen Associated Molecular Patterns (PAMPs) to induce secretion of pro-inflammatory cytokines IL-1β and IL-18. Additionally, α-hemolysin induces cell death in these cells through an NLRP3-dependent program of cellular necrosis, resulting in the release of endogenous pro-inflammatory molecules, like the chromatin-associated protein, High-mobility group box 1 (HMGB1). These studies link the activity of a major S. aureus virulence factor to a specific host signaling pathway. The cellular events linked to inflammasome activity have clear relevance to the disease processes associated with CA-MRSA including tissue necrosis and inflammation. PMID:19826485

  5. Staphylococcus aureus alpha-hemolysin activates the NLRP3-inflammasome in human and mouse monocytic cells.

    Science.gov (United States)

    Craven, Robin R; Gao, Xi; Allen, Irving C; Gris, Denis; Bubeck Wardenburg, Juliane; McElvania-Tekippe, Erin; Ting, Jenny P; Duncan, Joseph A

    2009-10-14

    Community Acquired Methicillin Resistant Staphylococcus aureus (CA-MRSA) causes severe necrotizing infections of the skin, soft tissues, and lungs. Staphylococcal alpha-hemolysin is an essential virulence factor in mouse models of CA-MRSA necrotizing pneumonia. S. aureus alpha-hemolysin has long been known to induce inflammatory signaling and cell death in host organisms, however the mechanism underlying these signaling events were not well understood. Using highly purified recombinant alpha-hemolysin, we now demonstrate that alpha-hemolysin activates the Nucleotide-binding domain and leucine-rich repeat containing gene family, pyrin domain containing 3 protein (NLRP3)-inflammasome, a host inflammatory signaling complex involved in responses to pathogens and endogenous danger signals. Non-cytolytic mutant alpha-hemolysin molecules fail to elicit NLRP3-inflammasome signaling, demonstrating that the responses are not due to non-specific activation of this innate immune signaling system by bacterially derived proteins. In monocyte-derived cells from humans and mice, inflammasome assembly in response to alpha-hemolysin results in activation of the cysteine proteinase, caspase-1. We also show that inflammasome activation by alpha-hemolysin works in conjunction with signaling by other CA-MRSA-derived Pathogen Associated Molecular Patterns (PAMPs) to induce secretion of pro-inflammatory cytokines IL-1beta and IL-18. Additionally, alpha-hemolysin induces cell death in these cells through an NLRP3-dependent program of cellular necrosis, resulting in the release of endogenous pro-inflammatory molecules, like the chromatin-associated protein, High-mobility group box 1 (HMGB1). These studies link the activity of a major S. aureus virulence factor to a specific host signaling pathway. The cellular events linked to inflammasome activity have clear relevance to the disease processes associated with CA-MRSA including tissue necrosis and inflammation.

  6. Human Sperm Interaction with Staphylococcus aureus: A Molecular Approach

    Directory of Open Access Journals (Sweden)

    Sonia Gupta

    2012-01-01

    Full Text Available Sperm immobilization factor (SIF causing 100% immobilization of spermatozoa isolated from Staphylococcus aureus when characterized using LC-MS (Liquid chromatography-mass spectrometry showed that this 20 kDa protein had peptide sequence similarity with hsp-70 protein. It was found to completely (100% inhibit Mg++ ATPase activity of spermatozoa at concentration of 100 μg mL−1. Sperm samples treated with SIF also showed reduction in calcium ionophore-induced acrosome reaction as compared to control samples (treated with calcium ionophore alone. Binding studies of FITC labelled SIF with spermatozoa using fluorescent microscopy showed binding of SIF to the surface of spermatozoa indicating the presence of SIF binding receptor. The receptor was extracted by 3M NaCl and purified by gel permeation chromatography. Characterization of the receptor by MALDI-TOF (Matrix-assisted laser desorption ionization-time of flight indicated that the receptor shared sequence similarity with MHC class II antigen. A calorimetric study showed that the receptor moiety on spermatozoa was specific for the purified ligand as binding of the receptor to ligand was enthalpically (−11.9 kJ mole−1 as well as entropically (21.53 J mole−1 K−1 favored resulting in the Gibb's free energy of −18.57 kJ mole−1.

  7. Staphylococcus aureus carriage in selected kindergartens in Klang Valley.

    Science.gov (United States)

    Mohamed, N A; Ramli, S; Amin, N N Z; Sulaiman, W S W; Isahak, I; Jamaluddin, T Z M T; Salleh, N M

    2016-04-01

    Nasal colonisation of S. aureus in healthy children was 18% to 30%. One to three percent of them were colonised by Methicillin-resistant Staphlycoccus aureus (MRSA). Although MRSA infection has become increasingly reported, population-based S. aureus and MRSA colonisation estimates are lacking. The main objective of this study was to determine the prevalence of S. aureus carriage among children. Nasal samples for S. aureus culture were obtained from 250 children from three kindergartens in the Klang Valley, after consent was obtained from the children and their parents. Swabs were transported in Stuart medium, and inoculated on mannitol-salt agar within four hours of collection. Identification and disk diffusion test were done according to guidelines. Polymerase chain reaction was done on MRSA isolates for the presence of mecA and lukS/FPV genes. Overall prevalence of S. aureus and MRSA carriage were 19.2% (48/250) and 1.6% (4/250) respectively. mecA gene was present in all isolates, 50% isolates carried Panton-Valentine leucocidin (PVL) gene. Sccmec type I was found in 2 isolates and the remaining isolates has Sccmec type V. The prevalence of S. aureus and MRSA carriage were similar to other studies. However, risk of contracting severe infection might be higher due to presence of PVL gene in half of the MRSA isolates.

  8. Staphylococcus aureus infections following knee and hip prosthesis insertion procedures.

    Science.gov (United States)

    Arduino, Jean Marie; Kaye, Keith S; Reed, Shelby D; Peter, Senaka A; Sexton, Daniel J; Chen, Luke F; Hardy, N Chantelle; Tong, Steven Yc; Smugar, Steven S; Fowler, Vance G; Anderson, Deverick J

    2015-01-01

    Staphylococcus aureus is the most common and most important pathogen following knee and hip arthroplasty procedures. Understanding the epidemiology of invasive S. aureus infections is important to quantify this serious complication. This nested retrospective cohort analysis included adult patients who had undergone insertion of knee or hip prostheses with clean or clean-contaminated wound class at 11 hospitals between 2003-2006. Invasive S. aureus infections, non-superficial incisional surgical site infections (SSIs) and blood stream infections (BSIs), were prospectively identified following each procedure. Prevalence rates, per 100 procedures, were estimated. 13,719 prosthetic knee (62%) and hip (38%) insertion procedures were performed. Of 92 invasive S. aureus infections identified, SSIs were more common (80%) than SSI and BSI (10%) or BSI alone (10%). The rate of invasive S. aureus infection/100 procedures was 0.57 [95% CI: 0.43-0.73] for knee insertion and 0.83 [95% CI: 0.61-1.08] for hip insertion. More than half (53%) were methicillin-resistant. Median time-to-onset of infection was 34 and 26 days for knee and hip insertion, respectively. Infection was associated with higher National Healthcare Safety Network risk index (p ≤ 0.0001). Post-operative invasive S. aureus infections were rare, but difficult-to-treat methicillin-resistant infections were relatively common. Optimizing preventative efforts may greatly reduce the healthcare burden associated with S. aureus infections.

  9. Epic Immune Battles of History: Neutrophils vs. Staphylococcus aureus

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    Fermin E. Guerra

    2017-06-01

    Full Text Available Neutrophils are the most abundant leukocytes in human blood and the first line of defense after bacteria have breached the epithelial barriers. After migration to a site of infection, neutrophils engage and expose invading microorganisms to antimicrobial peptides and proteins, as well as reactive oxygen species, as part of their bactericidal arsenal. Ideally, neutrophils ingest bacteria to prevent damage to surrounding cells and tissues, kill invading microorganisms with antimicrobial mechanisms, undergo programmed cell death to minimize inflammation, and are cleared away by macrophages. Staphylococcus aureus (S. aureus is a prevalent Gram-positive bacterium that is a common commensal and causes a wide range of diseases from skin infections to endocarditis. Since its discovery, S. aureus has been a formidable neutrophil foe that has challenged the efficacy of this professional assassin. Indeed, proper clearance of S. aureus by neutrophils is essential to positive infection outcome, and S. aureus has developed mechanisms to evade neutrophil killing. Herein, we will review mechanisms used by S. aureus to modulate and evade neutrophil bactericidal mechanisms including priming, activation, chemotaxis, production of reactive oxygen species, and resolution of infection. We will also highlight how S. aureus uses sensory/regulatory systems to tailor production of virulence factors specifically to the triggering signal, e.g., neutrophils and defensins. To conclude, we will provide an overview of therapeutic approaches that may potentially enhance neutrophil antimicrobial functions.

  10. Silver nanoparticles for the inhibition of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Ortiz-Gila

    2015-01-01

    Full Text Available Existe un gran ecosistema microbiano en la cavidad oral donde Staphylococcus aureus ( S. aureus se puede encontrar, causando patologías orales tales como quelitis angular, las paperas y la mucositis estafilocócica. Estas enfermedades producidas por S. aureus en la cavidad oral son consecuencia de los factores de virulencia, toxinas y multiresistencia a los antibióticos, lo que contribuye a la infección. La colonización en la cavidad oral por S. aureus en pacientes sanos es de 24% a 36%. Sin embargo, la incidencia aumenta a 48% en pacientes con prótesis debido a la formación de biofilms en la superficie de las dentaduras postizas. Actualmente, no existe ningún tratamiento para infecciones orales sin el uso de antibióticos. Investigaciones recientes indican que las nanopartículas de plata (AgNPs son un material o estrategia para eliminar S. aureus debido a su efecto antibacteriano. Sin embargo, el mecanismo del efecto inhibidor de los iones de Ag sobre S. aureus es sólo parcialmente conocida y muy poco se ha informado. Por lo tanto, el propósito de la presente revisión sistemática es determinar las estrategias y retos de la utilización de biomateriales antimicrobianos con AgNPs frente a las infecciones orales de S. aureus.

  11. [Eradication of Staphylococcus aureus in carrier patients undergoing joint arthroplasty].

    Science.gov (United States)

    Barbero Allende, José M; Romanyk Cabrera, Juan; Montero Ruiz, Eduardo; Vallés Purroy, Alfonso; Melgar Molero, Virginia; Agudo López, Rosa; Gete García, Luis; López Álvarez, Joaquín

    2015-02-01

    Prosthetic joint infection (PJI) is a complication with serious repercussions and its main cause is Staphylococcus aureus. The purpose of this study is to determine whether decolonization of S.aureus carriers helps to reduce the incidence of PJI by S.aureus. An S.aureus screening test was performed on nasal carriers in patients undergoing knee or hip arthroplasty between January and December 2011. Patients with a positive test were treated with intranasal mupirocin and chlorhexidine soap 5 days. The incidence of PJI was compared with patients undergoing the same surgery between January and December 2010. A total of 393 joint replacements were performed in 391 patients from the control group, with 416 joint replacements being performed in the intervention group. Colonization study was performed in 382 patients (91.8%), of which 102 were positive (26.7%) and treated. There was 2 PJI due S.aureus compared with 9 in the control group (0.5% vs 2.3%, odds ratio [OR]: 0.2, 95% confidence interval [CI]: 0.4 to 2.3, P=.04). In our study, the detection of colonization and eradication of S.aureus carriers achieved a significant decrease in PJI due to S.aureus compared to a historical group. Copyright © 2013 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  12. The changing epidemiology of Staphylococcus aureus bloodstream infection

    DEFF Research Database (Denmark)

    Laupland, K.B.; Lyytikäinen, O.; Søgaard, Mette

    2013-01-01

    Clin Microbiol Infect ABSTRACT: Although the epidemiology of Staphylococcus aureus bloodstream infection (BSI) has been changing, international comparisons are lacking. We sought to determine the incidence of S. aureus BSI and assess trends over time and by region. Population-based surveillance...... episodes of S. aureus BSI were identified. The overall annual incidence rate for S. aureus BSI was 26.1 per 100 000 population, and those for methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) were 24.2 and 1.9 per 100 000, respectively. Although the overall incidence...... of community-onset MSSA BSI (15.0 per 100 000) was relatively similar across regions, the incidence rates of hospital-onset MSSA (9.2 per 100 000), community-onset MRSA (1.0 per 100 000) and hospital-onset MRSA (0.8 per 100 000) BSI varied substantially. Whereas the overall incidence of S. aureus BSI did...

  13. Epic Immune Battles of History: Neutrophils vs. Staphylococcus aureus

    Science.gov (United States)

    Guerra, Fermin E.; Borgogna, Timothy R.; Patel, Delisha M.; Sward, Eli W.; Voyich, Jovanka M.

    2017-01-01

    Neutrophils are the most abundant leukocytes in human blood and the first line of defense after bacteria have breached the epithelial barriers. After migration to a site of infection, neutrophils engage and expose invading microorganisms to antimicrobial peptides and proteins, as well as reactive oxygen species, as part of their bactericidal arsenal. Ideally, neutrophils ingest bacteria to prevent damage to surrounding cells and tissues, kill invading microorganisms with antimicrobial mechanisms, undergo programmed cell death to minimize inflammation, and are cleared away by macrophages. Staphylococcus aureus (S. aureus) is a prevalent Gram-positive bacterium that is a common commensal and causes a wide range of diseases from skin infections to endocarditis. Since its discovery, S. aureus has been a formidable neutrophil foe that has challenged the efficacy of this professional assassin. Indeed, proper clearance of S. aureus by neutrophils is essential to positive infection outcome, and S. aureus has developed mechanisms to evade neutrophil killing. Herein, we will review mechanisms used by S. aureus to modulate and evade neutrophil bactericidal mechanisms including priming, activation, chemotaxis, production of reactive oxygen species, and resolution of infection. We will also highlight how S. aureus uses sensory/regulatory systems to tailor production of virulence factors specifically to the triggering signal, e.g., neutrophils and defensins. To conclude, we will provide an overview of therapeutic approaches that may potentially enhance neutrophil antimicrobial functions. PMID:28713774

  14. Disruption of Methicillin-resistant Staphylococcus aureus Biofilms with Enzymatic Therapeutics

    Science.gov (United States)

    2015-04-29

    NAVAL MEDICAL RESEARCH UNIT SAN ANTONIO Disruption of Methicillin-resistant Staphylococcus aureus Biofilms with Enzymatic...Methicillin-resistant Staphylococcus aureus MSSA Methicillin-sensitive Staphylococcus aureus OD Optical density PBS Phosphate-buffered saline SEM... Staphylococcus aureus biofilm model that mimics wound-like conditions and employ this model to evaluate the anti-biofilm activity of four enzymatic compounds

  15. Clinical significance of Staphylococcus aureus bacteriuria in a nationwide study of adults with S. aureus bacteraemia.

    Science.gov (United States)

    Asgeirsson, Hilmir; Kristjansson, Mar; Kristinsson, Karl G; Gudlaugsson, Olafur

    2012-01-01

    To evaluate the clinical significance of Staphylococcus aureus bacteriuria (SABU) in adults with S. aureus bacteraemia (SAB). All individuals ≥18 years old diagnosed with SAB in Iceland between December 1st 2003 and November 30th 2008 were retrospectively identified. Data was collected from medical records. Concomitant SABU was defined as growth of S. aureus in a urine sample taken within 24 h of the index blood culture. SABU was seen in 27 of 166 (16.3%) SAB patients having urine cultured before administration of antibiotics, but after excluding those with SAB of urinary tract origin SABU was seen in 16 of 152 (10.5%). In this latter cohort SABU was independently associated with having endocarditis (RR 6.68; 95% CI 1.53-17.3) and admission to intensive-care unit (RR 2.84; 95% CI 1.25-4.44), while for having complicated SAB the RR was 1.56 (95% CI 0.96-1.80). No correlation was seen with mortality or relapse rates. SABU appears to be secondary to SAB in some cases while it is the primary infection causing SAB in others. In patients with SAB of non-urinary tract origin SABU should probably be regarded as distant haematogenous seeding and a marker of deep tissue dissemination, thus affecting general management and treatment duration. Copyright © 2011 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  16. Staphylococcus aureus Central Nervous System Infections in Children.

    Science.gov (United States)

    Vallejo, Jesus G; Cain, Alexandra N; Mason, Edward O; Kaplan, Sheldon L; Hultén, Kristina G

    2017-10-01

    Central nervous system (CNS) infections caused by Staphylococcus aureus are uncommon in pediatric patients. We review the epidemiology, clinical features and treatment in 68 patients with a S. aureus CNS infection evaluated at Texas Children's Hospital. Cases of CNS infection in children with positive cerebrospinal fluid cultures or spinal epidural abscess (SEA) for S. aureus at Texas Children's Hospital from 2001 to 2013 were reviewed. Seventy cases of S. aureus CNS infection occurred in 68 patients. Forty-nine cases (70%) were secondary to a CNS device, 5 (7.1%) were postoperative meningitis, 9 (12.8%) were hematogenous meningitis and 7 (10%) were SEAs. Forty-seven (67.2%) were caused by methicillin-sensitive S. aureus (MSSA) and 23 (32.8%) by methicillin-resistant S. aureus (MRSA). Community-acquired infections were more often caused by MRSA that was clone USA300/pvl. Most patients were treated with nafcillin (MSSA) or vancomycin (MRSA) with or without rifampin. Among patients with MRSA infection, 50% had a serum vancomycin trough obtained with the median level being 10.6 μg/mL (range: 5.4-15.7 μg/mL). Only 1 death was associated with S. aureus infection. The epidemiology of invasive of S. aureus infections continues to evolve with MSSA accounting for most of the infections in this series. The majority of cases were associated with neurosurgical procedures; however, hematogenous S. aureus meningitis and SEA occurred as community-acquired infections in patients without predisposing factors. Patients with MRSA CNS infections had a favorable response to vancomycin, but the beneficial effect of combination therapy or targeting vancomycin trough concentrations of 15-20 μg/mL remains unclear.

  17. A Split Staphylococcus aureus Cas9 as a Compact Genome-Editing Tool in Plants

    OpenAIRE

    Kaya, Hidetaka; Ishibashi, Kazuhiro; Toki, Seiichi

    2017-01-01

    Split-protein methods?where a protein is split into two inactive fragments that must re-assemble to form an active protein?can be used to regulate the activity of a given protein and reduce the size of gene transcription units. Here, we show that a Staphylococcus aureus Cas9 (SaCas9) can be split, and that split-SaCas9 expressed from Agrobacterium can induce targeted mutagenesis in Nicotiana benthamiana. Since SaCas9 is smaller than the more commonly used Cas9 derived from Streptococcus pyoge...

  18. Acute phase proteins in bovine milk in an experimental model of Staphylococcus aureus subclinical mastitis

    DEFF Research Database (Denmark)

    Eckersall, P D; Young, F J; Nolan, A M

    2006-01-01

    The objectives were to establish the origin of 2 acute phase proteins in milk during subclinical bovine mastitis and to characterize the relationship between those proteins in milk and blood. Haptoglobin (Hp) and mammary-associated serum amyloid A (M-SAA3) appear in milk during mastitis, whereas Hp...... and serum amyloid A increase in serum during mastitis. The concentrations of these proteins were determined in an experimental model using a field strain of Staphylococcus aureus to induce subclinical mastitis in dairy cows. The expression of mRNA coding for these proteins was assessed and the presence of M...

  19. Evaluation of a lysostaphin-fusion protein as a dry-cow therapy for Staphylococcus aureus mastitis in dairy cattle.

    Science.gov (United States)

    Hoernig, K J; Donovan, D M; Pithua, P; Williams, F; Middleton, J R

    2016-06-01

    This study evaluated the efficacy of a recombinant lysostaphin fused to a protein transduction domain (rLYS-PTD) as a dry-cow therapy for the treatment of experimentally induced chronic, subclinical Staphylococcus aureus mastitis. Twenty-two Holstein dairy cows were experimentally infected with Staph. aureus in a single pair of diagonal mammary quarters approximately 45d before dry off. Staphylococcus aureus-infected mammary quarters of cows were randomly assigned to 1 of 2 treatment groups at dry off: (1) 279mg of rLYS-PTD in 50mL of vehicle (n=11 cows; 22 quarters) or (2) 50mL of vehicle solution (n=11 cows; 22 quarters) by intramammary infusion. All cows were followed for 30d postpartum to determine cure rates using bacteriologic culture, somatic cell counts, and clinical mastitis scores. No cures were recorded in either the treatment or control groups. Milk somatic cell count, bacterial colony counts, and mastitis scores did not significantly differ between treatment groups. In conclusion, rLYS-PTD was not an effective dry-cow therapeutic for chronic, subclinical Staph. aureus mastitis at the tested dose and formulation. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Evaluation of the effects of Extremely Low Frequency (ELF Pulsed Electromagnetic Fields (PEMF on survival of the bacterium Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Ahmed Istiaque

    2013-12-01

    In summary, the growth rate of the irradiated S. aureus bacteria is affected by radiation of particular parameters, thus revealing resonant effects induced by the applied radiation. The decreased CFU values in all irradiated samples compared to control samples (non-exposed were observed. Findings provide important insight towards selecting the optimal parameters of ELF PEMF for possible treatment of infected tissue and thus, wound healing promotion.

  1. Methicillin-resistant Staphylococcus aureus in a finger felon.

    Science.gov (United States)

    Connolly, B; Johnstone, F; Gerlinger, T; Puttler, E

    2000-01-01

    Methicillin-resistant Staphylococcus aureus is an increasingly prevalent nosocomial pathogen that presents therapeutic challenges. We report an incidence of methicillin-resistant S aureus in a felon. The biochemical and clinical characteristics of methicillin-resistant S aureus are reviewed. The alarming increase of this organism in various types of infections demands the attention of all surgeons and emphasizes the importance of early surgical drainage and culture of pus in all cases of infection. (J Hand Surg 2000; 25A:173-175. Copyright 2000 by the American Society for Surgery of the Hand.).

  2. Bovine Staphylococcus aureus: Subtyping, evolution, and zoonotic transfer.

    Science.gov (United States)

    Boss, R; Cosandey, A; Luini, M; Artursson, K; Bardiau, M; Breitenwieser, F; Hehenberger, E; Lam, Th; Mansfeld, M; Michel, A; Mösslacher, G; Naskova, J; Nelson, S; Podpečan, O; Raemy, A; Ryan, E; Salat, O; Zangerl, P; Steiner, A; Graber, H U

    2016-01-01

    Staphylococcus aureus is globally one of the most important pathogens causing contagious mastitis in cattle. Previous studies using ribosomal spacer (RS)-PCR, however, demonstrated in Swiss cows that Staph. aureus isolated from bovine intramammary infections are genetically heterogeneous, with Staph. aureus genotype B (GTB) and GTC being the most prominent genotypes. Furthermore, Staph. aureus GTB was found to be contagious, whereas Staph. aureus GTC and all the remaining genotypes were involved in individual cow disease. In addition to RS-PCR, other methods for subtyping Staph. aureus are known, including spa typing and multilocus sequence typing (MLST). They are based on sequencing the spa and various housekeeping genes, respectively. The aim of the present study was to compare the 3 analytic methods using 456 strains of Staph. aureus isolated from milk of bovine intramammary infections and bulk tanks obtained from 12 European countries. Furthermore, the phylogeny of animal Staph. aureus was inferred and the zoonotic transfer of Staph. aureus between cattle and humans was studied. The analyzed strains could be grouped into 6 genotypic clusters, with CLB, CLC, and CLR being the most prominent ones. Comparing the 3 subtyping methods, RS-PCR showed the highest resolution, followed by spa typing and MLST. We found associations among the methods but in many cases they were unsatisfactory except for CLB and CLC. Cluster CLB was positive for clonal complex (CC)8 in 99% of the cases and typically positive for t2953; it is the cattle-adapted form of CC8. Cluster CLC was always positive for tbl 2645 and typically positive for CC705. For CLR and the remaining subtypes, links among the 3 methods were generally poor. Bovine Staph. aureus is highly clonal and a few clones predominate. Animal Staph. aureus always evolve from human strains, such that every human strain may be the ancestor of a novel animal-adapted strain. The zoonotic transfer of IMI- and milk-associated strains

  3. Staphylococcus aureus and the ecology of the nasal microbiome

    DEFF Research Database (Denmark)

    Liu, Cindy M; Price, Lance B; Hungate, Bruce A

    2015-01-01

    The human microbiome can play a key role in host susceptibility to pathogens, including in the nasal cavity, a site favored by Staphylococcus aureus. However, what determines our resident nasal microbiota-the host or the environment-and can interactions among nasal bacteria determine S. aureus...... colonization? Our study of 46 monozygotic and 43 dizygotic twin pairs revealed that nasal microbiota is an environmentally derived trait, but the host's sex and genetics significantly influence nasal bacterial density. Although specific taxa, including lactic acid bacteria, can determine S. aureus colonization...

  4. The Effect of Essential Oils on Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Seda Ozdikmenli

    2014-05-01

    Full Text Available Diseases caused by Staphylococcus aureus are widespread through the world in spite of developing technology. S. aureus is an important pathogen causing food intoxications besides hospital infections by its antibiotic resistant strains. Nowadays, there has been worldwide increasing concern on usage of natural products to control microorganisms. One of these natural products is essential oils. They are produced from plants especially from spices and composed of many components and volatiles. This review summarizes informative literature on essential oils and their mode of antimicrobial action. In addition, current knowledge on in vitro researches on antibacterial activity of essential oils and food applications to control S. aureus has been discussed.

  5. Staphylococcus aureus 'Down Under': contemporary epidemiology of S. aureus in Australia, New Zealand, and the South West Pacific.

    Science.gov (United States)

    Williamson, D A; Coombs, G W; Nimmo, G R

    2014-07-01

    The clinical and molecular epidemiology of Staphylococcus aureus disease has changed considerably over the past two decades, particularly with the emergence and spread of community-associated methicillin-resistant S. aureus (CA-MRSA) clones. Indeed, some of the first global descriptions of CA-MRSA were from remote indigenous communities in Western Australia, and from Pacific Peoples in New Zealand. The epidemiology of S. aureus infections in the South West Pacific has several unique features, largely because of the relative geographical isolation and unique indigenous communities residing in this region. In particular, a number of distinct CA-MRSA clones circulate in Australia and New Zealand, such as sequence type (ST) 93 methicillin-resistant S. aureus (MRSA) (Queensland clone) and clonal complex 75 S. aureus (Staphylococcus argenteus) in Australia, and ST30 MRSA (Southwest Pacific clone) in New Zealand. In addition, there is a disproportionate burden of S. aureus disease in indigenous paediatric populations, particularly in remote Aboriginal communities in Australia, and in Pacific Peoples and Maori in New Zealand. In this review, we provide a contemporary overview of the clinical and molecular epidemiology of S. aureus disease in the South West Pacific region, with a particular focus on features distinct to this region. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

  6. Staphylococcus aureus intestinal colonization is associated with increased frequency of S. aureus on skin of hospitalized patients

    Directory of Open Access Journals (Sweden)

    Donskey Curtis J

    2007-09-01

    Full Text Available Abstract Background Intestinal colonization by Staphylococcus aureus among hospitalized patients has been associated with increased risk of staphylococcal infection and could potentially contribute to transmission. We hypothesized that S. aureus intestinal colonization is associated with increased frequency of S. aureus on patients' skin and nearby environmental surfaces. Methods Selected inpatients were cultured weekly for S. aureus from stool, nares, skin (groin and axilla, and environmental surfaces (bed rail and bedside table. Investigator's hands were cultured after contacting the patients' skin and the environmental surfaces. Results Of 71 subjects, 32 (45.1% had negative nares and stool cultures, 23 (32.4% had positive nares and stool cultures, 13 (18.3% were nares carriers only, and 3 (4.2% were stool carriers only. Of the 39 patients with S. aureus carriage, 30 (76.9% had methicillin-resistant isolates. In comparison to nares colonization only, nares and intestinal colonization was associated with increased frequency of positive skin cultures (41% versus 77%; p = 0.001 and trends toward increased environmental contamination (45% versus 62%; p = 0.188 and acquisition on investigator's hands (36% versus 60%; p = 0.057. Patients with negative nares and stool cultures had low frequency of S. aureus on skin and the environment (4.8% and 11.3%, respectively. Conclusion We found that hospitalized patients with S. aureus nares and/or stool carriage frequently had S. aureus on their skin and on nearby environmental surfaces. S. aureus intestinal colonization was associated with increased frequency of positive skin cultures, which could potentially facilitate staphylococcal infections and nosocomial transmission.

  7. Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection.

    Directory of Open Access Journals (Sweden)

    Nathan B Pincus

    Full Text Available The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a "post-antibiotic era", the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA, in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

  8. Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection.

    Science.gov (United States)

    Pincus, Nathan B; Reckhow, Jensen D; Saleem, Danial; Jammeh, Momodou L; Datta, Sandip K; Myles, Ian A

    2015-01-01

    The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a "post-antibiotic era", the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA), in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

  9. Local Epidermal Growth Factor Receptor Signaling Mediates the Systemic Pathogenic Effects of Staphylococcus aureus Toxic Shock Syndrome.

    Directory of Open Access Journals (Sweden)

    Laura M Breshears

    Full Text Available Secreted factors of Staphylococcus aureus can activate host signaling from the epidermal growth factor receptor (EGFR. The superantigen toxic shock syndrome toxin-1 (TSST-1 contributes to mucosal cytokine production through a disintegrin and metalloproteinase (ADAM-mediated shedding of EGFR ligands and subsequent EGFR activation. The secreted hemolysin, α-toxin, can also induce EGFR signaling and directly interacts with ADAM10, a sheddase of EGFR ligands. The current work explores the role of EGFR signaling in menstrual toxic shock syndrome (mTSS, a disease mediated by TSST-1. The data presented show that TSST-1 and α-toxin induce ADAM- and EGFR-dependent cytokine production from human vaginal epithelial cells. TSST-1 and α-toxin also induce cytokine production from an ex vivo porcine vaginal mucosa (PVM model. EGFR signaling is responsible for the majority of IL-8 production from PVM in response to secreted toxins and live S. aureus. Finally, data are presented demonstrating that inhibition of EGFR signaling with the EGFR-specific tyrosine kinase inhibitor AG1478 significantly increases survival in a rabbit model of mTSS. These data indicate that EGFR signaling is critical for progression of an S. aureus exotoxin-mediated disease and may represent an attractive host target for therapeutics.

  10. Macrophage Bactericidal Activities against Staphylococcus aureus Are Enhanced In Vivo by Selenium Supplementation in a Dose-Dependent Manner.

    Science.gov (United States)

    Aribi, Mourad; Meziane, Warda; Habi, Salim; Boulatika, Yasser; Marchandin, Hélène; Aymeric, Jean-Luc

    2015-01-01

    Dietary selenium is of fundamental importance to maintain optimal immune function and enhance immunity during infection. To this end, we examined the effect of selenium on macrophage bactericidal activities against Staphylococcus aureus. Assays were performed in golden Syrian hamsters and peritoneal macrophages cultured with S. aureus and different concentrations of selenium. Infected and selenium-supplemented animals have significantly decreased levels of serum nitric oxide (NO) production when compared with infected but non-selenium-supplemented animals at day 7 post-infection (p selenium induced a significant decrease in macrophage NO production, but significant increase in hydrogen peroxide (H2O2) levels (respectively, p = 0.009, p selenium; the optimal macrophage activity levels were reached at 20 ng/mL. The concentration of 5 ng/mL of selenium induced a significant decrease in the bacterial arginase activity but a significant increase in the macrophage arginase activity. The dose of 20 ng/mL selenium induced a significant decrease of bacterial growth (p Selenium acts in a dose-dependent manner on macrophage activation, phagocytosis and bacterial killing suggesting that inadequate doses may cause a loss of macrophage bactericidal activities and that selenium supplementation could enhance the in vivo control of immune response to S. aureus.

  11. Genome-Wide Analysis of Ruminant Staphylococcus aureus Reveals Diversification of the Core Genome▿ †

    OpenAIRE

    Ben Zakour, Nouri L; Sturdevant, Daniel E.; Even, Sergine; Guinane, Caitriona M.; Barbey, Corinne; Alves, Priscila D.; Cochet, Marie-Françoise; Gautier, Michel; Otto, Michael; Fitzgerald, J. Ross; Le Loir, Yves

    2008-01-01

    Staphylococcus aureus causes disease in humans and a wide array of animals. Of note, S. aureus mastitis of ruminants, including cows, sheep, and goats, results in major economic losses worldwide. Extensive variation in genome content exists among S. aureus pathogenic clones. However, the genomic variation among S. aureus strains infecting different animal species has not been well examined. To investigate variation in the genome content of human and ruminant S. aureus, we carried out whole-ge...

  12. Daptomycin-Nonsusceptible, Vancomycin-Intermediate, Methicillin-Resistant Staphylococcus aureus Endocarditis

    Directory of Open Access Journals (Sweden)

    Ryan Yu

    2012-01-01

    Full Text Available Due to the emergence of Staphylococcus aureus with reduced vancomycin susceptibility, newer antibiotics, including daptomycin, have been used to treat methicillin-resistant S aureus infections. Daptomycin is a cyclic lipopeptide that is approved to treat S aureus bacteremia and right-sided endocarditis, and reports of S aureus with reduced susceptibility to daptomycin are infrequent. To our knowledge, the present report describes the first Canadian case of daptomycin-nonsusceptible, vancomycin-intermediate S aureus infection.

  13. Inducible Clindamycin Resistance among Staphylococci Isolated from Burn Patients

    Directory of Open Access Journals (Sweden)

    KS Ghenghesh

    2009-01-01

    Full Text Available Clindamycin has been used successfully to treat pneumonia and soft-tissue infections caused by methicillin-resistant Staphylococcus aureus. However, inducible clindamycin resistance has been described as a cause of treatment failure of such infections. A total of 159 staphylococcal isolates from different clinical specimens from burn patients in Tripoli Burn Center were tested for inducible clindamycin resistance by the disk-diffusion induction test. Inducible clindamycin resistance was detected in 66.2% of 65 methicillin-resistant S. aureus isolates and in none of 55 methicillin-sensitiveS. aureus, 10 methicillin-resistant coagulase negative staphylococci and 29 methicllin-sensitive coagulase negative staphylococci isolates. In our setting, clindamycin can be used for the treatmentof infections due to staphylococci, but we recommend that staphylococci isolates, particularly methicillin-resistant S. aureus, are tested by the D-test before treatment.

  14. Toxicity test and bacteriophage typing of Staphylococcus aureus ...

    African Journals Online (AJOL)

    , however, the prevalence of phage group III and α-haemolytic strains of S. aureus calls for concern since these groups have frequently been implicated in food borne diseases. Effective hazard analysis critical control point (HACCP) evaluation ...

  15. The Pre - Eminence of Staphylococcus Aureus as The Causative ...

    African Journals Online (AJOL)

    Specimens were collected for culture and sensitivity before commencement of antibiotic therapy. The major isolated organism was Staphylococcus aureus. Others were Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris Proteus rettgerri, Alkaligenes faecalis, Acinetobacter calcoaceticus ...

  16. A Closer Look at the Transcriptome of Staphylococcus aureus

    NARCIS (Netherlands)

    Smits, N.J.P.

    2012-01-01

    Tight regulation of genes upon changing environments is important in establishing and maintaining infections by pathogens. In Staphylococcus aureus, gene expression and particularly controlled expression of various groups of genes dependent on growth and environmental conditions is essential for

  17. Multilocus sequence typing of Staphylococcus aureus with DNA array technology

    NARCIS (Netherlands)

    W.B. van Leeuwen (Willem); C. Jay (Corinne); S.V. Snijders (Susan); N. Durin (Nathalia); B. Lacroix (Bruno); H.A. Verbrugh (Henri); M.C. Enright (Mark); A. Troesch (Alain); A.F. van Belkum (Alex)

    2003-01-01

    textabstractA newly developed oligonucleotide array suited for multilocus sequence typing (MLST) of Staphylococcus aureus strains was analyzed with two strain collections in a two-center study. MLST allele identification for the first strain collection fully agreed with

  18. Sensibilité aux antibiotiques des souches de staphylococcus aureus ...

    African Journals Online (AJOL)

    Sensibilité aux antibiotiques des souches de staphylococcus aureus communautaires dans la région de Nouakchott (Mauritanie). Mohamed Lemine Ould Salem, Sidi Mohamed Ghaber, Sidi El Wafi Ould Baba, Mohamed Mahmoud Ould Maouloud ...

  19. Host- and tissue-specific pathogenic traits of Staphylococcus aureus.

    NARCIS (Netherlands)

    W.B. van Leeuwen (Willem); D.C. Melles (Damian); A. Alaidan (Alwaleed); M. Al-Ahdal (Mohammed); H.A.M. Boelens (Hélène); S.V. Snijders (Susan); H.F.L. Wertheim (Heiman); E. van Duijkeren (Engeline); J.K. Peeters (Justine); P.J. van der Spek (Peter); R.F.J. Gorkink (Raymond); G. Simons (Guus); H.A. Verbrugh (Henri); A.F. van Belkum (Alex)

    2005-01-01

    textabstractComparative genomics were used to assess genetic differences between Staphylococcus aureus strains derived from infected animals versus colonized or infected humans. A total of 77 veterinary isolates were genetically characterized by high-throughput amplified fragment length polymorphism

  20. Left-sided native valve Staphylococcus aureus endocarditis

    NARCIS (Netherlands)

    Slabbekoorn, M.; Horlings, H. M.; van der Meer, J. T. M.; Windhausen, A.; Van der Sloot, J. A. P.; Lagrand, W. K.

    2010-01-01

    Despite improved diagnostic tools and expanded treatment options, left-sided native valve endocarditis caused by Staphylococcus aureus infection remains a serious and destructive disease. The high morbidity and mortality, however, can be reduced by early recognition, correct diagnosis, and

  1. Improving Diagnosis and Treatment of Staphylococcus aureus Infections : Experimental Studies

    NARCIS (Netherlands)

    S. van den Berg (Sanne)

    2015-01-01

    markdownabstract__Abstract__ Staphylococcus aureus is an opportunistic pathogen that causes a variety of infections, ranging from mild skin infections like furuncles and impetigo, to severe, lifethreatening infections including endocarditis, osteomyelitis and pneumonia. Invasive infections are

  2. Prevalence and risk factors for Staphylococcus aureus and ...

    African Journals Online (AJOL)

    2015-09-05

    Sep 5, 2015 ... Materials and Methods: Nasal samples were taken from anterior nares ..... 3599 preoperative nasal cultures for a year and found 16.6% .... methicillin‑resistant and methicillin‑susceptible Staphylococcus aureus in nursing.

  3. Staphylococcus aureus and the ecology of the nasal microbiome

    Science.gov (United States)

    Liu, Cindy M.; Price, Lance B.; Hungate, Bruce A.; Abraham, Alison G.; Larsen, Lisbeth A.; Christensen, Kaare; Stegger, Marc; Skov, Robert; Andersen, Paal Skytt

    2015-01-01

    The human microbiome can play a key role in host susceptibility to pathogens, including in the nasal cavity, a site favored by Staphylococcus aureus. However, what determines our resident nasal microbiota—the host or the environment—and can interactions among nasal bacteria determine S. aureus colonization? Our study of 46 monozygotic and 43 dizygotic twin pairs revealed that nasal microbiota is an environmentally derived trait, but the host’s sex and genetics significantly influence nasal bacterial density. Although specific taxa, including lactic acid bacteria, can determine S. aureus colonization, their negative interactions depend on thresholds of absolute abundance. These findings demonstrate that nasal microbiota is not fixed by host genetics and opens the possibility that nasal microbiota may be manipulated to prevent or eliminate S. aureus colonization. PMID:26601194

  4. Truncated Autoinducing Peptide Conjugates Selectively Recognize and Kill Staphylococcus aureus.

    Science.gov (United States)

    Tsuchikama, Kyoji; Shimamoto, Yasuhiro; Anami, Yasuaki

    2017-06-09

    The accessory gene regulator (agr) of Staphylococcus aureus coordinates various pathogenic events and is recognized as a promising therapeutic target for virulence control. S. aureus utilizes autoinducing peptides (AIPs), cyclic-peptide signaling molecules, to mediate the agr system. Despite the high potency of synthetic AIP analogues in agr inhibition, the potential of AIP molecules as a delivery vehicle for antibacterial agents remains unexplored. Herein, we report that truncated AIP scaffolds can be fused with fluorophore and cytotoxic photosensitizer molecules without compromising their high agr inhibitory activity, binding affinity to the receptor AgrC, or cell specificity. Strikingly, a photosensitizer-AIP conjugate exhibited 16-fold greater efficacy in a S. aureus cell-killing assay than a nontargeting analogue. These findings highlight the potential of truncated AIP conjugates as useful chemical tools for in-depth biological studies and as effective anti-S. aureus agents.

  5. Simple method for correct enumeration of Staphylococcus aureus

    DEFF Research Database (Denmark)

    Haaber, J.; Cohn, M. T.; Petersen, A.

    2016-01-01

    culture. When grown in such liquid cultures, the human pathogen Staphylococcus aureus is characterized by its aggregation of single cells into clusters of variable size. Here, we show that aggregation during growth in the laboratory standard medium tryptic soy broth (TSB) is common among clinical...... and laboratory S. aureus isolates and that aggregation may introduce significant bias when applying standard enumeration methods on S. aureus growing in laboratory batch cultures. We provide a simple and efficient sonication procedure, which can be applied prior to optical density measurements to give...... an accurate estimate of cellular numbers in liquid cultures of S. aureus regardless of the aggregation level of the given strain. We further show that the sonication procedure is applicable for accurate determination of cell numbers using agar plate counting of aggregating strains....

  6. Antibiotic sensitivity pattern of Staphylococcus aureus from clinical

    African Journals Online (AJOL)

    raoul

    2011-01-26

    Jan 26, 2011 ... Erythromycin, Chloramphenicol, Cotrimoxazole, Tetracycline, Penicillin, Ciprofloxacin, Ofloxacin, Levofloxacin, Ceftriaxone, Amoxycillin and vancomycin were 92.4% .... Kirmany N, Tuazon CV, Alling D. Carriage of Staphylococcus aureus among patients receiving allergy injections. Ann allergy. 1980;.

  7. IL-21 Is Increased in Nasal Polyposis and after Stimulation with Staphylococcus aureus Enterotoxin B.

    Science.gov (United States)

    Calus, Lien; Derycke, Lara; Dullaers, Melissa; Van Zele, Thibaut; De Ruyck, Natalie; Pérez-Novo, Claudina; Holtappels, Gabriele; De Vos, Geert; Lambrecht, Bart N; Bachert, Claus; Gevaert, Philippe

    2017-01-01

    Chronic rhinosinusitis with nasal polyposis (CRSwNP) is an inflammatory disease associated with lymphoid aggregates and local IgE production related to Staphylococcus aureus enterotoxins. T-follicular helper cells and their effector cytokine interleukin (IL)-21 play an important role in germinal center proliferation. IL-21 was determined on the mRNA level by qPCR in nasal tissue of 3 groups of patients: control (n = 17), chronic rhinosinusitis without nasal polyposis (CRSsNP; n = 23), and CRSwNP (n = 35). The expression of IL-21 by CD4+ T cells was analyzed in tissue at baseline and after 24-h stimulation of tissue fragments with S. aureus enterotoxin B (SEB) using flow cytometry. Finally, human nasal IL-21+CXCR5+CD4+ T cells were isolated and coincubated with human blood naive B cells to investigate their functionality. IL-21 mRNA expression was increased in the CRSwNP group (p B-cell lymphoma-6 and B-lymphocyte-induced maturation protein-1 were upregulated in CRSwNP versus CRSsNP. Furthermore, SEB was able to increase IL-21 mRNA expression significantly (p B cells. IL-21- and IL-21-producing CD4+ T cells were increased in CRSwNP. In addition, SEB induced an increase in IL-21 and IL-21+CD4+ T cells, suggesting that S. aureus can modulate the function of Tfh cells in nasal polyps. We speculate that T-follicular helper cells and IL-21 are important in the pathophysiology of CRSwNP. © 2017 S. Karger AG, Basel.

  8. Detection of Macrolide, Lincosamide and Streptogramin Resistance among Methicillin Resistant Staphylococcus aureus (MRSA in Mumbai

    Directory of Open Access Journals (Sweden)

    Arunagiri Subramanian

    2015-01-01

    Full Text Available Background: The increase in incidence of Methicillin Resistant Staphyloccocus aureus (MRSA and its extraordinary potential to develop antimicrobial resistance has highlighted the need for better agents to treat such infections. This has led to a renewed interest in use of new drugs for treatment with clindamycin and quinuprsitin-dalfopristin being the preferred choice for treatment. Aim & Objectives: This study was undertaken to detect the prevalence of MacrolideLincosamide-Streptogramin (MLS resistance among clinical isolates of MRSA.Material and Methods:Two hundred and thirty clinical isolates of S. aureus were subjected to routine antibiotic susceptibility testing including cefoxitin, erythromycin and quinupristindalfopristin. Inducible resistance to clindamycin was tested by 'D' test as per Clinical and Laboratory Standards Institute (CLSI guidelines. Results: Out of all S. aureus isolates, 93.91% were identified as MRSA. In the disc diffusion testing, 81.5% of isolates showed erythromycin resistance. Among these, the prevalence of constitutive (cMLS , inducible (iMLS b b and MS-phenotype were 35.80%, 31.82% and 32.39% respectively by the D-test method. 77.8% of isolates were resistant to quinupristin-dalfopristin and the Minimum Inhibitory Concentration (MIC ranged from 4–32 µg/ml. 89.20% of isolates were resistant to both quinupristin-dalfopristin and erythromycin of which 35.03%, 35.67% and 29.30% belonged to iMLS , cMLS and MS phenotype respectively. Conclusion: The emergence of quinupristindalfopristin resistance and MLS phenotypes brings b about the need for the simple and reliable D-test in routine diagnosis and further susceptibility testing for proper antimicrobial therapy.

  9. Combined multiplex loop-mediated isothermal amplification with lateral flow assay to detect sea and seb genes of enterotoxic Staphylococcus aureus.

    Science.gov (United States)

    Yin, H Y; Fang, T J; Wen, H W

    2016-07-01

    Staphylococcal enterotoxins (SEs) are the most common cause of food poisoning worldwide and can induce symptoms, such as diarrhoea, vomiting and abdominal cramping. Thus, the aim of this study is to develop a multiplex loop-mediated isothermal amplification combined with a lateral flow assay (m-LAMP/LFA) to simultaneously detect the sea and seb genes of Staphylococcus aureus. The amplicons of the sea gene were labelled with digoxigenin (Dig) and biotin while those of seb gene were labelled with fluorescein isothiocyanate (FITC) and biotin. These amplicons were detected using a multiplex LFA with NeutrAvidin-tagged gold nanoparticles as the detection reagent. After optimization, the detection limit of this assay was 10(2)  CFU ml(-1) Staph. aureus, which was one tenth that of a multiplex PCR. This assay did not exhibit any cross-reactivity in detecting other enterotoxic Staph. aureus strains or other food pathogens. After 6 h of enrichment, this developed assay detected 1 CFU ml(-1) of Staph. aureus in milk, apple juice, cheese and rice. The developed m-LAMP/LFA method does not require expensive equipment and can be completely implemented within an 8-h workday. Therefore, this method can provide an effective means of quickly screening staphylococcal enterotoxin A- and/or staphylococcal enterotoxin B-producing Staph. aureus in food samples. Staphylococcus aureus is one of the major foodborne pathogens worldwide, and its staphylococcal enterotoxin A and B are strongly associated with food poisoning. This work developed a multiplex loop-mediated isothermal amplification combined with a lateral flow assay (m-LAMP/LFA) to simultaneously detect the sea and seb genes of Staph. aureus in food samples. The assay has good specificity and sensitivity with ease-of-use features, making it ideal for on-site detection. © 2016 The Society for Applied Microbiology.

  10. Methicillin-resistant Staphylococcus aureus in a neonatal alpaca

    OpenAIRE

    Stull, Jason W.; Kenney, Daniel G.; Slavić, Durda; Weese, J Scott

    2012-01-01

    A 6-hour-old alpaca was presented for evaluation of respiratory difficulty. As part of routine surveillance, methicillin-resistant Staphylococcus aureus (MRSA) was identified from a nasal swab taken upon admission to the hospital. No signs of MRSA infection were noted. The MRSA strain recovered was a human epidemic clone that has been associated with horses. Methicillin-resistant S. aureus colonization can occur in camelids, and the potential animal and public health risks require consideration.

  11. Membrane damage elicits an immunomodulatory program in Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Ahmed S Attia

    2010-03-01

    Full Text Available The Staphylococcus aureus HrtAB system is a hemin-regulated ABC transporter composed of an ATPase (HrtA and a permease (HrtB that protect S. aureus against hemin toxicity. S. aureus strains lacking hrtA exhibit liver-specific hyper-virulence and upon hemin exposure over-express and secrete immunomodulatory factors that interfere with neutrophil recruitment to the site of infection. It has been proposed that heme accumulation in strains lacking hrtAB is the signal which triggers S. aureus to elaborate this anti-neutrophil response. However, we report here that S. aureus strains expressing catalytically inactive HrtA do not elaborate the same secreted protein profile. This result indicates that the physical absence of HrtA is responsible for the increased expression of immunomodulatory factors, whereas deficiencies in the ATPase activity of HrtA do not contribute to this process. Furthermore, HrtB expression in strains lacking hrtA decreases membrane integrity consistent with dysregulated permease function. Based on these findings, we propose a model whereby hemin-mediated over-expression of HrtB in the absence of HrtA damages the staphylococcal membrane through pore formation. In turn, S. aureus senses this membrane damage, triggering the increased expression of immunomodulatory factors. In support of this model, wildtype S. aureus treated with anti-staphylococcal channel-forming peptides produce a secreted protein profile that mimics the effect of treating DeltahrtA with hemin. These results suggest that S. aureus senses membrane damage and elaborates a gene expression program that protects the organism from the innate immune response of the host.

  12. Staphylococcus aureus nasal carriage in hemodialysis centers of Fez, Morocco.

    Science.gov (United States)

    Diawara, Idrissa; Bekhti, Khadija; Elhabchi, Driss; Saile, Rachid; Elmdaghri, Naima; Timinouni, Mohammed; Elazhari, Mohamed

    2014-06-01

    Staphylococcus aureus (S. aureus) nasal carriage may be responsible for some serious infections in hemodialyzed patients. The main target of this study was to estimate the prevalence of S. aureus nasal carriage in hemodialysis outpatients and medical staff in hemodialysis centers specifically in Fez region. The second target is to identify the risks of colonization, resistance pattern of isolates and their virulence toxin genes. Nasal swab specimens were obtained from 143 hemodialyzed outpatients and 32 medical staff from January to June 2012. Each participant completed a short questionnaire. Nasal carriage of S. aureus was demographically related (age, gender, hemodialysis duration), comorbidity (diabetes, malignancy) and exposure to health care (dialysis staff, hospitalization). PCR (Polymerase Chain Reaction) were used on all the isolates in the research of twelve staphylococcal enterotoxins genes. Also the PCR was used to investigate on the three factors epidermal cell differentiation inhibitors; three exfoliatin toxins; two leukotoxins; the toxic shock syndrome toxin-1 and the hemolysin beta genes. Nasal screening revealed 38.16%, 50% and 18.75% S. aureus carries in chronic, acute hemodialysis patients and medical staff, respectively. Only young participants were likely to be S. aureus carries (p = 0.002). But there were no gender differences between the isolate carriers and non-carriers or some comorbidity factors such as viral hepatitis B and C, HIV (Human Immunodeficiency Virus) infections, diabetes, chronic smoking, recent hospitalization or antibiotic therapy. Out of all isolates, only one (1.61%) was methicillin-resistant and Twenty-one (33.87%) had at least two virulence toxin genes. Knowledge and monitoring of antibiotic resistance profile and virulence of S. aureus carriage are essential in the treatment of infections generated by this pathogen, as well as in the control of clonal dissemination and prevent the spread of S. aureus resistance.

  13. Piperine, a Phytochemical Potentiator of Ciprofloxacin against Staphylococcus aureus

    Science.gov (United States)

    Khan, Inshad Ali; Mirza, Zahid Mehmood; Kumar, Ashwani; Verma, Vijeshwar; Qazi, Ghulam Nabi

    2006-01-01

    Piperine, a trans-trans isomer of 1-piperoyl-piperidine, in combination with ciprofloxacin markedly reduced the MICs and mutation prevention concentration of ciprofloxacin for Staphylococcus aureus, including methicillin-resistant S. aureus. The enhanced accumulation and decreased efflux of ethidium bromide in the wild-type and mutant (CIPr-1) strains in the presence of piperine suggest its involvement in the inhibition of bacterial efflux pumps. PMID:16436753

  14. An Improved Medium for Growing Staphylococcus aureus Biofilm

    Science.gov (United States)

    2012-04-19

    Branch, US Army Dental and Trauma Research Detachment, Institute of Surgical Research, Fort Sam Houston, TX 78234, United States a b s t r a c ta r t...hlgC), are up regulated Journal of Microbiological Methods 90 (2012) 115–118 ⁎ Corresponding author at: 3650 Chambers Pass, Bldg 3610, US Army Dental ...aureus biofilm formation in real time, we used overnight green fluores cent protein (GFP) tagged clinical isolate S. aureus UAMS 1 (University of

  15. Biochemical characters and antibiotic susceptibility of Staphylococcus aureus isolates

    OpenAIRE

    Subhankari Prasad Chakraborty; Santanu Kar Mahapatra; Somenath Roy

    2011-01-01

    Objective: To observe the biochemical characters and antibiotic susceptibility of isolated Staphylococcus aureus (S. auerus) strains against some conventional and traditional antibiotics. Methods: Thirty post operative pathogenic isolated S. aureus strains were used in this study. Bacterial culture was done in Mueller-Hinton broth at 37 °C. Characters of these strains were determined by traditional biochemical tests such as hydrolysis test of gelatin, urea, galactose, starch and protein, a...

  16. Staphylococcus aureus in the community: colonization versus infection.

    Directory of Open Access Journals (Sweden)

    Maureen Miller

    Full Text Available BACKGROUND: Antibiotic-resistant Staphylococcus aureus infections have increased dramatically in the community, yet S. aureus nasal colonization has remained stable. The objectives of this study were to determine if S. aureus colonization is a useful proxy measure to study disease transmission and infection in community settings, and to identify potential community reservoirs. METHODOLOGY/PRINCIPAL FINDINGS: Randomly selected households in Northern Manhattan, completed a structured social network questionnaire and provided nasal swabs that were typed by pulsed field gel electrophoresis to identify S. aureus colonizing strains. The main outcome measures were: 1 colonization with S. aureus; and 2 recent serious skin infection. Risk factor analyses were conducted at both the individual and the household levels; logistic regression models identified independent risks for household colonization and infection. RESULTS: 321 surveyed households contained 914 members. The S. aureus prevalence was 25% and MRSA was 0.4%. More than 40% of households were colonized. Recent antibiotic use was the only significant correlate for household colonization (p = .002. Seventy-eight (24% households reported serious skin infection. In contrast with colonization, five of the six risk factors that increased the risk of skin infection in the household at the univariate level remained independently significant in multivariable analysis: international travel, sports participation, surgery, antibiotic use and towel sharing. S. aureus colonization was not significantly associated with serious skin infection in any analysis. Among multiperson households with more than one person colonized, 50% carried the same strain. CONCLUSIONS/SIGNIFICANCE: The lack of association between S. aureus nasal colonization and serious skin infection underscores the need to explore alternative venues or body sites that may be crucial to transmission. Moreover, the magnitude of colonization and

  17. Glucose Augments Killing Efficiency of Daptomycin Challenged Staphylococcus aureus Persisters

    OpenAIRE

    Prax, Marcel; Mechler, Lukas; Weidenmaier, Christopher; Bertram, Ralph

    2016-01-01

    Treatment of Staphylococcus aureus in stationary growth phase with high doses of the antibiotic daptomycin (DAP) eradicates the vast majority of the culture and leaves persister cells behind. Despite resting in a drug-tolerant and dormant state, persister cells exhibit metabolic activity which might be exploited for their elimination. We here report that the addition of glucose to S. aureus persisters treated with DAP increased killing by up to five-fold within one hour. This glucose-DAP effe...

  18. Staphylococcus aureus Redirects Central Metabolism to Increase Iron Availability

    OpenAIRE

    Stauff, Devin L; Pishchany, Gleb; Whitwell, Corbin W; Torres, Victor J; Skaar, Eric P; Friedman, David J.

    2006-01-01

    Staphylococcus aureus pathogenesis is significantly influenced by the iron status of the host. However, the regulatory impact of host iron sources on S. aureus gene expression remains unknown. In this study, we combine multivariable difference gel electrophoresis and mass spectrometry with multivariate statistical analyses to systematically cluster cellular protein response across distinct iron-exposure conditions. Quadruplicate samples were simultaneously analyzed for alterations in protein ...

  19. Molecular dynamics of Staphylococcus aureus nasal carriage in Hajj pilgrims.

    Science.gov (United States)

    Verhoeven, P O; Gautret, P; Haddar, C H; Benkouiten, S; Gagnaire, J; Belhouchat, K; Grattard, F; Charrel, R; Pozzetto, B; Drali, T; Lucht, F; Brouqui, P; Memish, Z A; Berthelot, P; Botelho-Nevers, E

    2015-07-01

    During the 2012 Hajj season, the risk of acquisition of Staphylococcus aureus nasal carriage in a cohort of French pilgrims was 22.8%, and was statistically associated with the acquisition of viral respiratory pathogens (p 0.03). The carriage of S. aureus belonging to the emerging clonal complex 398 significantly increased following the pilgrimage (p < 0.05). Copyright © 2015 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  20. Nickel allergy and relationship with Staphylococcus aureus in atopic dermatitis.

    Science.gov (United States)

    Bogdali, Anna M; Anna, Bogdali M; Grazyna, Antoszczyk; Wojciech, Dyga; Aleksander, Obtulowicz; Anna, Bialecka; Andrzej, Kasprowicz; Zofia, Magnowska; Krystyna, Obtulowicz

    2016-01-01

    The increase of nickel air pollution is supposed to frequent side effects of nickel action related to virulence potential of Staphylococcus aureus in patients with nickel allergy in atopic dermatitis. The goal was to investigate the relationship between nickel allergy and infection by S. aureus in atopic dermatitis. Nickel allergy was confirmed in atopic patients and excluded in healthy volunteers using patch testing. Infection by S. aureus was tested in atopic patients and healthy volunteers by use of API Staph system. The specific IgE for staphylococcal enterotoxin A and B were measured. Secretion of IFN-g, IL-2, IL-13 by PBMC under nickel sulfate and the enterotoxins A and B stimulations were studied with ELISpot. We found the increased number of infections by S. aureus in atopic patients with nickel allergy in comparison to atopic patients and healthy volunteers without nickel allergy. The elevated secretion of IL-2 under nickel sulfate stimulation in vitro was exclusively found in atopic patients with nickel allergy infected by S. aureus. Our data suggest that nickel allergy and infection by S. aureus are linked in atopic dermatitis. Copyright © 2015 Elsevier GmbH. All rights reserved.

  1. Prevalence of nasal portal of Staphylococcus aureus in disabled children.

    Directory of Open Access Journals (Sweden)

    Clotilde Molin

    2016-06-01

    Full Text Available Introduction: Colonization of the nasal mucosa by Staphylococcus aureus set a carrier state. Which is recognized as a potential source of infection and a high risk factor for subsequent invasive infections. The prevalence of nasal carriage of this germ in disabled children in Paraguay is not known, thus contributing to the knowledge of their frequency and evaluate the profile of sensitivity to common antimicrobials was conducted this study, from May to July 2015.  Objective: to determine the prevalence of Staphylococcus aureus nasal carriage and profile of antimicrobial resistance in disabled children. Materials and Methods: A descriptive cross-sectional study in which 80 nasal swabs of children, who attended the service laboratory of SENADIS (Secretaria Nacional por los Derechos Humanos de las Personas con Discapacidad. The identification and sensitivity of germ was accomplished by conventional testing.  Results: 80 pediatric patients, 46 boys and 34 girls. 18 isolates of Staphylococcus aureus were obtained, corresponding to a prevalence of 22,5%. Susceptibility testing indicated that 14 strains were MSSA (Methicillin – Sensitive Staphylococcus aureus and 4 RMSA ( Methicillin- resistant Staphylococcus aureus. Conclusion: The prevalence of Staphylococcus aureus in a population with its own characteristics provides valuable data for the epidemiology, reflecting the need for continued vigilance and take steps to reduce associated infections. The detection of RMAR evidences their progress; it is important to evaluate the empirical treatment to primary care.

  2. Resistance to Antimicrobials Mediated by Efflux Pumps in Staphylococcus aureus

    Science.gov (United States)

    Costa, Sofia S.; Junqueira, Elisabete; Palma, Cláudia; Viveiros, Miguel; Melo-Cristino, José; Amaral, Leonard; Couto, Isabel

    2013-01-01

    Resistance mediated by efflux has been recognized in Staphylococcus aureus in the last few decades, although its clinical relevance has only been recognized recently. The existence of only a few studies on the individual and overall contribution of efflux to resistance phenotypes associated with the need of well-established methods to assess efflux activity in clinical isolates contributes greatly to the lack of solid knowledge of this mechanism in S. aureus. This study aims to provide information on approaches useful to the assessment and characterization of efflux activity, as well as contributing to our understanding of the role of efflux to phenotypes of antibiotic resistance and biocide tolerance in S. aureus clinical isolates. The results described show that efflux is an important contributor to fluoroquinolone resistance in S. aureus and suggest it as a major mechanism in the early stages of resistance development. We also show that efflux plays an important role on the reduced susceptibility to biocides in S. aureus, strengthening the importance of this long neglected resistance mechanism to the persistence and proliferation of antibiotic/biocide-resistant S. aureus in the hospital environment. PMID:27029294

  3. Macrophage Bactericidal Activities against Staphylococcus aureus Are Enhanced In Vivo by Selenium Supplementation in a Dose-Dependent Manner.

    Directory of Open Access Journals (Sweden)

    Mourad Aribi

    Full Text Available Dietary selenium is of fundamental importance to maintain optimal immune function and enhance immunity during infection. To this end, we examined the effect of selenium on macrophage bactericidal activities against Staphylococcus aureus.Assays were performed in golden Syrian hamsters and peritoneal macrophages cultured with S. aureus and different concentrations of selenium.Infected and selenium-supplemented animals have significantly decreased levels of serum nitric oxide (NO production when compared with infected but non-selenium-supplemented animals at day 7 post-infection (p < 0.05. A low dose of 5 ng/mL selenium induced a significant decrease in macrophage NO production, but significant increase in hydrogen peroxide (H2O2 levels (respectively, p = 0.009, p < 0.001. The NO production and H2O2 levels were significantly increased with increasing concentrations of selenium; the optimal macrophage activity levels were reached at 20 ng/mL. The concentration of 5 ng/mL of selenium induced a significant decrease in the bacterial arginase activity but a significant increase in the macrophage arginase activity. The dose of 20 ng/mL selenium induced a significant decrease of bacterial growth (p < 0.0001 and a significant increase in macrophage phagocytic activity, NO production/arginase balance and S. aureus killing (for all comparisons, p < 0.001.Selenium acts in a dose-dependent manner on macrophage activation, phagocytosis and bacterial killing suggesting that inadequate doses may cause a loss of macrophage bactericidal activities and that selenium supplementation could enhance the in vivo control of immune response to S. aureus.

  4. Efficacy profile of a bivalent Staphylococcus aureus glycoconjugated vaccine in adults on hemodialysis: Phase III randomized study.

    Science.gov (United States)

    Fattom, Ali; Matalon, Albert; Buerkert, John; Taylor, Kimberly; Damaso, Silvia; Boutriau, Dominique

    2015-01-01

    In a previous study in end-stage renal disease (ESRD) hemodialysis patients, a single dose of Staphylococcus aureus type 5 and 8 capsular polysaccharides (T5/T8) conjugated to nontoxic recombinant Pseudomonas aeruginosa exotoxin A investigational vaccine showed no efficacy against S. aureus bacteremia 1 year post-vaccination, but a trend for efficacy was observed over the first 40 weeks post-vaccination. Vaccine efficacy (VE) of 2 vaccine doses was therefore evaluated. In a double-blind trial 3359 ESRD patients were randomized (1:1) to receive vaccine or placebo at week 0 and 35. VE in preventing S. aureus bacteremia was assessed between 3-35 weeks and 3-60 weeks post-dose-1. Anti-T5 and anti-T8 antibodies were measured. Serious adverse events (SAEs) were recorded for 42 days post-vaccination and deaths until study end. No significant difference in the incidence of S. aureus bacteremia was observed between vaccine and placebo groups between weeks 3-35 weeks post-dose 1 (VE -23%, 95%CI: -98;23, p = 0.39) or at 3-60 weeks post-dose-1 (VE -8%, 95%CI: -57;26, p = 0.70). Day 42 geometric mean antibody concentrations were 272.4 μg/ml and 242.0 μg/ml (T5 and T8, respectively) in vaccinees. SAEs were reported by 24%/25.3% of vaccinees/placebo recipients. These data do not show a protective effect of either 1 or 2 vaccine doses against S. aureus bacteremia in ESRD patients. The vaccine induced a robust immune response and had an acceptable safety profile. Further investigation suggested possible suboptimal vaccine quality (manufacturing) and a need to expand the antigen composition of the vaccine. This study is registered at www.clinicaltrials.gov NCT00071214.

  5. The agr inhibitors solonamide B and analogues alter immune responses to Staphylococccus aureus but do not exhibit adverse effects on immune cell functions

    DEFF Research Database (Denmark)

    Baldry, Mara; Kitir, Betül; Frøkiær, Hanne

    2016-01-01

    Staphylococcus aureus infections are becoming increasingly difficult to treat due to antibiotic resistance with the community-associated methicillin-resistant S. aureus (CA-MRSA) strains such as USA300 being of particular concern. The inhibition of bacterial virulence has been proposed...... with concomitant repression of surface-expressed adhesins. Solonamide B, a non-ribosomal depsipeptide of marine bacterial origin, was recently identified as a putative anti-virulence compound that markedly reduced expression of α-hemolysin and phenol-soluble modulins. To further strengthen solonamide anti...... with agr, while immune cell activity and integrity is generally not affected. Furthermore, treatment of S. aureus with selected solonamides was found to only marginally influence the interaction with fibronectin and biofilm formation, thus addressing the concern that application of compounds inducing...

  6. Staphylococcus aureus α-hemolysin promotes platelet-neutrophil aggregate formation.

    Science.gov (United States)

    Parimon, Tanyalak; Li, Zhi; Bolz, Devin D; McIndoo, Eric R; Bayer, Clifford R; Stevens, Dennis L; Bryant, Amy E

    2013-09-01

    Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) causes severe hemorrhagic necrotizing pneumonia associated with high mortality. Exotoxins have been implicated in the pathogenesis of this infection; however, the cellular mechanisms responsible remain largely undefined. Because platelet-neutrophil aggregates (PNAs) can dysregulate inflammatory responses and contribute to tissue destruction, we investigated whether exotoxins from MRSA could stimulate formation of PNAs in human whole blood. Strong PNA formation was stimulated by toxins from stationary phase but not log phase CA-MRSA, and α-hemolysin was singularly identified as the mediator of this activity. MRSA exotoxins also caused neutrophil (polymorphonuclear leukocyte) activation, as measured by increased CD11b expression, although platelet binding was not driven by this mechanism; rather, α-hemolysin-induced PNA formation was solely platelet P-selectin dependent. These findings suggest a role for S. aureus α-hemolysin-induced PNA formation in alveolar capillary destruction in hemorrhagic/necrotizing pneumonia caused by CA-MRSA and offer novel targets for intervention.

  7. ANTISTAPHYBASE: database of antimicrobial peptides (AMPs) and essential oils (EOs) against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus.

    Science.gov (United States)

    Zouhir, Abdelmajid; Taieb, Malek; Lamine, Mohamed Ashraf; Cherif, Ammar; Jridi, Taoufik; Mahjoubi, Basma; Mbarek, Sarra; Fliss, Ismail; Nefzi, Adel; Sebei, Khaled; Ben Hamida, Jeannette

    2017-03-01

    Staphylococcus aureus and methicillin-resistant S. aureus are major pathogens. The antimicrobial peptides and essential oils (EOs) display narrow- or broad-spectrum activity against bacteria including these strains. A centralized resource, such as a database, designed specifically for anti-S. aureus/anti-methicillin-resistant S. aureus antimicrobial peptides and EOs is therefore needed to facilitate the comprehensive investigation of their structure/activity associations and combinations. The database ANTISTAPHYBASE is created to facilitate access to important information on antimicrobial peptides and essential peptides against methicillin-resistant S. aureus and S. aureus. At the moment, the database contains 596 sequences of antimicrobial peptides produced by diverse organisms and 287 essential oil records. It permits a quick and easy search of peptides based on their activity as well as their general, physicochemical properties and literature data. These data are very useful to perform further bioinformatic or chemometric analysis and would certainly be useful for the development of new drugs for medical use. The ANTISTAPHYBASE database is freely available at: https://www.antistaphybase.com/ .

  8. Disruption of the sigS gene attenuates the local innate immune response to Staphylococcus aureus in a mouse mastitis model.

    Science.gov (United States)

    Peton, Vincent; Breyne, Koen; Rault, Lucie; Demeyere, Kristel; Berkova, Nadia; Meyer, Evelyne; Even, Sergine; Le Loir, Yves

    2016-04-15

    Staphylococcus aureus (S. aureus) is a major pathogen involved in ruminant mastitis and present worldwide. Clinical signs of S. aureus mastitis vary considerably and are largely dependent on strain-specific factors. A comparison of two S. aureus strains that reproducibly induced either severe (O11) or mild (O46) mastitis in ewes revealed that the transcriptional regulator sigS was mutated in O46 (Le Maréchal et al., 2011. PLoS One. 6 (11) e27354. doi:10.1371/journal.pone.0027354). In the present paper, we analysed the sigS sequence in 18 other S. aureus strains isolated from goat or ewe mastitis and found a 4-bp deletion similar to that of the O46 sigS gene in three strains associated with subclinical ewe mastitis. This sigS gene was disrupted in strain O11 (O11ΔsigS), so our aim was to investigate its involvement in the severity of infections in the context of mastitis. The wild type (wt) and mutant strains were then characterized in vitro to determine the involvement of sigS in the response S. aureus under various stress conditions, and assess its influence on the cytotoxicity of the pathogen, its invasive capacity and biofilm formation. The strains were compared in vivo in an experimental mouse mastitis model in which clinical signs and cytokine production were evaluated at 24h post-infection. While no significant differences in the effect on bacterial growth between O11 and O11ΔsigS were observed either in vitro or in vivo, a significantly weaker in vivo production of interleukin (IL)-1α, IL-1β, and Tumor Necrosis Factor (TNF)-α was measured in the mammary glands infected with the mutant strain, suggesting that infection with O11ΔsigS induced an attenuated local innate immune response. These results suggest an impact of sigS disruption on S. aureus pathogenesis in a ruminant mastitis context. This disruption is probably involved in, and may partly explain, the milder symptoms previously observed in S. aureus O46-induced mastitis in ewes. Copyright

  9. Predictors of Mortality in Staphylococcus aureus Bacteremia

    Science.gov (United States)

    Jensen, Slade O.; Vaska, Vikram L.; Espedido, Björn A.; Paterson, David L.; Gosbell, Iain B.

    2012-01-01

    Summary: Staphylococcus aureus bacteremia (SAB) is an important infection with an incidence rate ranging from 20 to 50 cases/100,000 population per year. Between 10% and 30% of these patients will die from SAB. Comparatively, this accounts for a greater number of deaths than for AIDS, tuberculosis, and viral hepatitis combined. Multiple factors influence outcomes for SAB patients. The most consistent predictor of mortality is age, with older patients being twice as likely to die. Except for the presence of comorbidities, the impacts of other host factors, including gender, ethnicity, socioeconomic status, and immune status, are unclear. Pathogen-host interactions, especially the presence of shock and the source of SAB, are strong predictors of outcomes. Although antibiotic resistance may be associated with increased mortality, questions remain as to whether this reflects pathogen-specific factors or poorer responses to antibiotic therapy, namely, vancomycin. Optimal management relies on starting appropriate antibiotics in a timely fashion, resulting in improved outcomes for certain patient subgroups. The roles of surgery and infectious disease consultations require further study. Although the rate of mortality from SAB is declining, it remains high. Future international collaborative studies are required to tease out the relative contributions of various factors to mortality, which would enable the optimization of SAB management and patient outcomes. PMID:22491776

  10. [Dispersal of Staphylococcus aureus from nasal carriers].

    Science.gov (United States)

    Iskandar, Aline; Nguyen, Ngan; Kolmos, Hans Jørn

    2009-02-02

    Staphylococcus aureus (Sa) is an important cause of hospital-acquired infections, and nasal carriage of Sa is common among health care workers. This study was designed to measure the airborne dispersal of Sa and other bacteria from such carriers and to investigate whether the use of cap, gown, gloves, and mask could reduce this dispersal. A total of 13 nasal Sa carriers were identified among 63 persons screened for Sa nasal carriage. The volunteers were studied for airborne dispersal of Sa in four different situations: quiet breathing, movements of the arms, whispering and loud talking. These activities were performed with and without gown, gloves, mask and cap upon street clothes. The study showed that the highest number of Sa and bacteria in total was dispersed into the air when the volunteers were moving and wearing only their street clothes. The dispersal of Sa into the air was reduced into a minimum by wearing cap, gown and gloves, and no further significant decrease was achieved by wearing a mask. This applied for all volunteers except for one, who had to wear a mask in order to reduce his dispersal of Sa to a minimum. The total dispersal of bacteria was significantly reduced by wearing cap, gown and gloves; however, to reduce this dispersal to a minimum, volunteers also had to wear a mask. Our study supports the rational basis that gown, cap, gloves and mask should be used not only in the operating theatre, but also while e.g. inserting central venous catheters.

  11. Antibiotic Resistance Profiling of Staphylococcus aureus Isolated from Clinical Specimens in a Tertiary Hospital from 2010 to 2012

    Directory of Open Access Journals (Sweden)

    Alain C. Juayang

    2014-01-01

    Full Text Available MRSA infection can affect a wide array of individuals that may lead to treatment failure. Also, the infection has the potential to spread from one area to another particularly health care facilities or communities eventually causing minor outbreaks. With this premise, the study aimed to describe MRSA infections using the hospital-based data of a tertiary hospital in Bacolod City, Philippines, from 2010 to 2012. Specifically, this study aimed to evaluate the antimicrobial resistance of S. aureus isolated from clinical specimens and to put emphasis on the prevalence of MRSA and Inducible Clindamycin Resistance. A total of 94 cases from 2010 to 2012 were diagnosed to have S. aureus infection using conventional bacteriologic methods. From these cases, 38 (40.6% were identified as MRSA and 37 (39.4% were inducible clindamycin resistant. Wounds and abscesses were considered to be the most common specimens with MRSA infections having 71.05% while blood was the least with 5.3%. For drug susceptibility, out of the 94 S. aureus cases, including MRSA, 100% were susceptible to linezolid making it the drug of choice for this study. It was then followed by tetracycline having a mean susceptibility of 95%;, while penicillin G was ineffective with 94 cases having 0% susceptibility.

  12. Staphylococcus aureus small colony variants in diabetic foot infections

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    Estrella Cervantes-García

    2015-03-01

    Full Text Available Background: Staphylococcus aureus (S. aureus is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA. A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs. Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods: A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results: We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions: The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections.

  13. Staphylococcus aureus small colony variants in diabetic foot infections.

    Science.gov (United States)

    Cervantes-García, Estrella; García-Gonzalez, Rafael; Reyes-Torres, Angélica; Resendiz-Albor, Aldo Arturo; Salazar-Schettino, Paz María

    2015-01-01

    Background : Staphylococcus aureus (S. aureus) is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA). A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs). Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods : A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results : We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions : The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections.

  14. Staphylococcus aureus from the German general population is highly diverse.

    Science.gov (United States)

    Becker, Karsten; Schaumburg, Frieder; Fegeler, Christian; Friedrich, Alexander W; Köck, Robin

    2017-01-01

    This prospective cohort study evaluates colonization dynamics and molecular characteristics of methicillin-susceptible and - resistant Staphylococcus aureus (MSSA/MRSA) in a German general population. Nasal swabs of 1878 non-hospitalized adults were screened for S. aureus. Participants were screened thrice in intervals of 6-8 months. Isolates were characterized by spa and agr typing, mecA and mecC possession, respectively, and PCRs targeting virulence factors. 40.9% of all participants carried S. aureus at least once while 0.7% of the participants carried MRSA (mainly spa t011). MSSA isolates (n=1359) were associated with 331 different spa types; t084 (7.7%), t091 (6.1%) and t012 (71, 5.2%) were predominant. Of 206 participants carrying S. aureus at all three sampling time points, 14.1% carried the same spa type continuously; 5.3% carried different spa types with similar repeat patterns, but 80.6% carried S. aureus with unrelated spa types. MSSA isolates frequently harboured genes encoding enterotoxins (sec: 16.6%, seg: 63.1%, sei: 64.5%) and toxic shock syndrome toxin (tst: 17.5%), but rarely Panton-Valentine leukocidin (lukS-PV/lukF-PV: 0.2%). MSSA colonizing human nares in the community are clonally highly diverse. Among those constantly carrying S. aureus, clonal lineages changed over time. The proportion of persistent S. aureus carriers was lower than reported elsewhere. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Catalase expression is modulated by vancomycin and ciprofloxacin and influences the formation of free radicals in Staphylococcus aureus cultures

    DEFF Research Database (Denmark)

    Wang, Ying; Hougaard, Anni Bygvrå; Paulander, Wilhelm Erik Axel

    2015-01-01

    was detected in broth medium without bacterial cells present and it was mitigated by iron chelation or by addition of catalase, which catalyzes the decomposition of hydrogen peroxide to water and oxygen. This suggests that the signal originates from hydroxyl radicals formed by the Fenton reaction, in which...... compared to the level seen with untreated bacterial cells. However, S. aureus cells express catalase, and the antibiotic-mediated increase in hydroxyl radical formation was correlated with reduced katA expression and catalase activity in the presence of either antibiotic. Therefore, our results show...... that in S. aureus, bactericidal antibiotics modulate catalase expression, which in turn influences the formation of free radicals in the surrounding broth medium. If similar regulation is found in other bacterial species, it might explain why bactericidal antibiotics are perceived as inducing formation...

  16. Staphylococcus aureus effect of different factors on mammary gland infection with staphylococcus aureus bacteria

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    Jurčevič Alen

    2004-01-01

    Full Text Available The objective of our investigation was to determine how certain factors (the environment, treatment, prevention, animal affect udder infection with Staphylococcus aureurs (S. aureus bacteria. A questionnaire investigated the effect of different factors on the frequency of infection with S. aureus bacteria. We established that prevention, treatment on the basis of results of bacteriological examinations and antibiograms, and the elimination of the negative influence of the environment, form a basis for reducing the frequency of udder infections. We verified the questionannire results with the variant analysis method and established that the effect of the environment significantly digresses from the other factors (prevention treatment and diagnosis, animal. Our results show that the breeder, with good prevention and good treatment of mastitis, often disregards the effects of the barn and the environment in which the cows are maintained. Poor barn conditions have a negative effect on cow resistance and at the same time enable the existence and multiplication of pathogenic species of bacteria. In addition to the maintenance conditions, one must not forget prevention and therapy of mammary gland inflammation, either. On the grounds of our previous investigations (Pengov et al., 2000, we recommend for the therapy of mammary gland inflammation the use of a combination of amoxicillin and clavulonic acid, and as prevention of mammary gland inflammation the use of an udder ointment.

  17. Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) at ambient freshwater beaches

    Science.gov (United States)

    Fogarty, Lisa R.; Haack, Sheridan K.; Johnson, Heather E.; Brennan, Angela K.; Isaacs, Natasha M.; Spencer, Chelsea

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) are a threat to human health worldwide, and although detected at marine beaches, they have been largely unstudied at freshwater beaches. Genes indicating S. aureus (SA; femA) and methicillin resistance (mecA) were detected at 11 and 12 of 13 US Great Lakes beaches and in 18% or 27% of 287 recreational water samples, respectively. Eight beaches had mecA + femA (potential MRSA) detections. During an intensive study, higher bather numbers, staphylococci concentrations, and femA detections were found in samples collected after noon than before noon. Local population density, beach cloud cover, and beach wave height were significantly correlated with SA or MRSA detection frequency. The Panton-Valentine leukocidin gene, associated with community-acquired MRSA, was detected in 12 out of 27 potential MRSA samples. The femA gene was detected less frequently at beaches that met US enterococci criteria or EU enterococci ‘excellent’ recreational water quality, but was not related to Escherichia coli-defined criteria. Escherichia coli is often the only indicator used to determine water quality at US beaches, given the economic and healthcare burden that can be associated with infections caused by SA and MRSA, monitoring of recreational waters for non-fecal bacteria such as staphylococci and/or SA may be warranted.

  18. Concomitant Staphylococcus aureus bacteriuria is associated with complicated S. aureus bacteremia.

    Science.gov (United States)

    Pulcini, Céline; Matta, Matta; Mondain, Véronique; Gaudart, Alice; Girard-Pipau, Fernand; Mainardi, Jean-Luc; Dellamonica, Pierre

    2009-10-01

    To identify factors associated with complicated Staphylococcus aureus bacteremia (SAB) in adults. Prospective observational multicenter study during 2 years in Nice University Hospital and during 6 months in the Hôpital Européen Georges Pompidou, Paris, including all adult inpatients with SAB assessed by an Infectious Diseases (ID) specialist. We included 104 SAB (79 in Nice and 25 in Paris), of which 45 were complicated, including 18 endocarditis and 23 bone and joint infections. A concomitant urine sample was performed in 65% of the cases, showing S. aureus bacteriuria 23/68 (34%) times. Blood cultures were drawn 48-96h after an appropriate antibiotic therapy had been started in 70 of the 104 cases (67%) and were positive in 28 cases (40%). The 3 following factors were found to be associated with complicated SAB in univariate analysis: community acquisition (56% vs 26%, P=0.002), concomitant bacteriuria (47% vs 19%, P=0.016) and persistent bacteremia (55% vs 26%, P=0.016). This last factor was associated with endocarditis, but not with other complications such as bone and joint infections.

  19. NH125 kills methicillin-resistant Staphylococcus aureus persisters by lipid bilayer disruption.

    Science.gov (United States)

    Kim, Wooseong; Fricke, Nico; Conery, Annie L; Fuchs, Beth Burgwyn; Rajamuthiah, Rajmohan; Jayamani, Elamparithi; Vlahovska, Petia M; Ausubel, Frederick M; Mylonakis, Eleftherios

    2016-01-01

    NH125, a known WalK inhibitor kills MRSA persisters. However, its precise mode of action is still unknown. The mode of action of NH125 was investigated by comparing its spectrum of antimicrobial activity and its effects on membrane permeability and giant unilamellar vesicles (GUVs) with walrycin B, a WalR inhibitor and benzyldimethylhexadecylammonium chloride (16-BAC), a cationic surfactant. NH125 killed persister cells of a variety of Staphylococcus aureus strains. Similar to 16-BAC, NH125 killed MRSA persisters by inducing rapid membrane permeabilization and caused the rupture of GUVs, whereas walrycin B did not kill MRSA persisters or induce membrane permeabilization and did not affect GUVs. NH125 kills MRSA persisters by interacting with and disrupting membranes in a detergent-like manner.

  20. Staphylococcus aureus: nuevos y antiguos antimicrobianos Staphylococcus aureus: new and old antimicrobial agents

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    B. Perazzi

    2010-09-01

    Full Text Available El objetivo del trabajo fue evaluar la sensibilidad a antiguos y nuevos antimicrobianos de aislamientos de Staphylococcus aureus resistentes a la oxacilina, de origen hospitalario (SAOR-H y adquiridos en la comunidad (SAOR-AC, y también en aislamientos sensibles a la oxacilina (SAOS. Se estudió en forma prospectiva la concentración inhibitoria mínima a diversos antimicrobianos en 118 aislamientos consecutivos por dilución seriada en agar según las indicaciones del CLSI. En los aislamientos de SAOR sin resistencia acompañante se determinó la presencia de los genes mec A, leucocidina de Panton Valentine (LPV y γ-hemolisina por PCR, y del cassette SCC mec por PCR múltiple. De los 118 aislamientos estudiados, 44 fueron SAOR-H, 16 SAOR-AC y 58 SAOS. Los aislamientos de SAOR-H presentaron resistencia simultánea a eritromicina, clindamicina, gentamicina, ciprofloxacina, levofloxacina y moxifloxacina, y todos fueron sensibles a tigeciclina (TIG, vancomicina, teicoplanina y linezolid (LZD. Los aislamientos de SAOR-AC fueron resistentes solamente a OXA y sensibles a todos los antimicrobianos ensayados. En todos ellos se detectaron los genes mec A, LPV, γ-hemolisina y el cassette SCC mec IV. En SAOS y en SAOR-AC todos los antimicrobianos no ß-lactámicos ensayados presentaron excelente actividad in vitro, mientras que en SAOR-H sólo los antiguos antimicrobianos como glucopéptidos, doxiciclina, rifampicina y trimetoprima-sulfametoxazol presentaron buena actividad in vitro, al igual que LZD y TIG entre los nuevos antimicrobianos. El fenotipo de SAOR sin resistencia acompañante fue altamente predictivo de SAOR-AC, ya que fue confirmado por presentar el cassette SCC mec IV.The objective of the study was to evaluate the susceptibility to old and new antimicrobial agents against hospital-acquired oxacillin-resistant Staphylococcus aureus (HA-ORSA, community-acquired oxacillin-resistant S. aureus (CA-ORSA, and oxacillin-susceptible S. aureus (OSSA

  1. Immunisation With Immunodominant Linear B Cell Epitopes Vaccine of Manganese Transport Protein C Confers Protection against Staphylococcus aureus Infection.

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    Hui-Jie Yang

    Full Text Available Vaccination strategies for Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA infections have attracted much research attention. Recent efforts have been made to select manganese transport protein C, or manganese binding surface lipoprotein C (MntC, which is a metal ion associated with pathogen nutrition uptake, as potential candidates for an S. aureus vaccine. Although protective humoral immune responses to MntC are well-characterised, much less is known about detailed MntC-specific B cell epitope mapping and particularly epitope vaccines, which are less-time consuming and more convenient. In this study, we generated a recombinant protein rMntC which induced strong antibody response when used for immunisation with CFA/IFA adjuvant. On the basis of the results, linear B cell epitopes within MntC were finely mapped using a series of overlapping synthetic peptides. Further studies indicate that MntC113-136, MntC209-232, and MntC263-286 might be the original linear B-cell immune dominant epitope of MntC, furthermore, three-dimensional (3-d crystal structure results indicate that the three immunodominant epitopes were displayed on the surface of the MntC antigen. On the basis of immunodominant MntC113-136, MntC209-232, and MntC263-286 peptides, the epitope vaccine for S. aureus induces a high antibody level which is biased to TH2 and provides effective immune protection and strong opsonophagocytic killing activity in vitro against MRSA infection. In summary, the study provides strong proof of the optimisation of MRSA B cell epitope vaccine designs and their use, which was based on the MntC antigen in the development of an MRSA vaccine.

  2. Femtosecond laser surface texturing of titanium as a method to reduce the adhesion of Staphylococcus aureus and biofilm formation

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Alexandre [Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bordeaux University, Institute of Chemistry & Biology of Membranes & Nanoobjects (CBMN UMR 5248, CNRS), European Institute of Chemistry and Biology, 2 Rue Robert Escarpit, 33607 Pessac (France); Elie, Anne-Marie [Bordeaux University, CBMN UMR 5248, CNRS, Bordeaux Science Agro, 1 Rue du G. de Gaulle, 33170 Gradignan (France); Plawinski, Laurent [Bordeaux University, Institute of Chemistry & Biology of Membranes & Nanoobjects (CBMN UMR 5248, CNRS), European Institute of Chemistry and Biology, 2 Rue Robert Escarpit, 33607 Pessac (France); Serro, Ana Paula [Instituto Superior Técnico, Universidade de Lisboa, CQE-Centro de Química Estrutural, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal); Botelho do Rego, Ana Maria [Instituto Superior Técnico, Universidade de Lisboa, CQFM-Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology - IN, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal); Almeida, Amélia [Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Urdaci, Maria C. [Bordeaux University, CBMN UMR 5248, CNRS, Bordeaux Science Agro, 1 Rue du G. de Gaulle, 33170 Gradignan (France); Durrieu, Marie-Christine [Bordeaux University, Institute of Chemistry & Biology of Membranes & Nanoobjects (CBMN UMR 5248, CNRS), European Institute of Chemistry and Biology, 2 Rue Robert Escarpit, 33607 Pessac (France); Vilar, Rui, E-mail: rui.vilar@tecnico.ulisboa.pt [Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2016-01-01

    Graphical abstract: - Highlights: • The short-term adhesion of Staphylococcus aureus onto femtosecond laser textured surfaces of titanium was investigated. • The laser textured surfaces consist of laser-induced periodic surface structures (LIPSS) and nanopillars. • The laser treatment enhances the hydrophilicity and the surface free energy of the material. • The laser treatment reduces significantly the adhesion of S. aureus and biofilm formation. • Femtosecond laser surface texturing of titanium is a simple and promising method for endowing dental and orthopedic implants with antibacterial properties. - Abstract: The aim of the present work was to investigate the possibility of using femtosecond laser surface texturing as a method to reduce the colonization of Grade 2 Titanium alloy surfaces by Staphylococcus aureus and the subsequent formation of biofilm. The laser treatments were carried out with a Yb:KYW chirped-pulse-regenerative amplification laser system with a central wavelength of 1030 nm and a pulse duration of 500 fs. Two types of surface textures, consisting of laser-induced periodic surface structures (LIPSS) and nanopillars, were produced. The topography, chemical composition and phase constitution of these surfaces were investigated by atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. Surface wettability was assessed by the sessile drop method using water and diiodomethane as testing liquids. The response of S. aureus put into contact with the laser treated surfaces in controlled conditions was investigated by epifluorescence microscopy and scanning electron microscopy 48 h after cell seeding. The results achieved show that the laser treatment reduces significantly the bacterial adhesion to the surface as well as biofilm formation as compared to a reference polished surfaces and suggest that femtosecond laser texturing is a simple and promising method

  3. Photothermal killing of Staphylococcus aureus using antibody-targeted gold nanoparticles.

    Science.gov (United States)

    Millenbaugh, Nancy J; Baskin, Jonathan B; DeSilva, Mauris N; Elliott, W Rowe; Glickman, Randolph D

    2015-01-01

    The continued emergence of multidrug resistant bacterial infections and the decline in discovery of new antibiotics are major challenges for health care throughout the world. This situation has heightened the need for novel antimicrobial therapies as alternatives to traditional antibiotics. The combination of metallic nanoparticles and laser exposure has been proposed as a strategy to induce physical damage to bacteria, regardless of antibiotic sensitivity. The purpose of this study was to test the antibacterial effect of antibody-targeted gold nanoparticles combined with pulsed laser irradiation. Gold nanoparticles conjugated to antibodies specific to Staphylococcus aureus peptidoglycan were incubated with suspensions of methicillin-resistant and methicillin-sensitive S. aureus (MRSA and MSSA). Bacterial suspensions were then exposed to 8 ns pulsed laser irradiation at a wavelength of 532 nm and fluences ranging from 1 to 5 J/cm(2). Viability of the bacteria following laser exposure was determined using colony forming unit assays. Scanning electron microscopy was used to confirm the binding of nanoparticles to bacteria and the presence of cellular damage. The laser-activated nanoparticle treatment reduced the surviving population to 31% of control in the MSSA population, while the survival in the MRSA population was reduced to 58% of control. Significant decreases in bacterial viability occurred when the laser fluence exceeded 1 J/cm(2), and this effect was linear from 0 to 5 J/cm(2) (r (2)=0.97). Significantly less bactericidal effect was observed for nonfunctionalized nanoparticles or functionalized nanoparticles without laser activation. Laser-activated nanoparticles targeted to S. aureus surface antigens significantly reduced the percentage of viable organisms and represents a promising new treatment modality that could be used either alone or as an adjunct to existing, conventional antibiotic therapy.

  4. Enzymatic degradation of in vitro Staphylococcus aureus biofilms supplemented with human plasma.

    Science.gov (United States)

    Watters, Chase M; Burton, Tarea; Kirui, Dickson K; Millenbaugh, Nancy J

    2016-01-01

    Enzymatic debridement is a therapeutic strategy used clinically to remove necrotic tissue from wounds. Some of the enzymes utilized for debridement have been tested against bacterial pathogens, but the effectiveness of these agents in dispersing clinically relevant biofilms has not been fully characterized. Here, we developed an in vitro Staphylococcus aureus biofilm model that mimics wound-like conditions and employed this model to investigate the antibiofilm activity of four enzymatic compounds. Human plasma at concentrations of 0%-50% was supplemented into growth media and used to evaluate biofilm biomass accumulation over 24 hours and 48 hours in one methicillin-sensitive and five methicillin-resistant strains of S. aureus. Supplementation of media with 10% human plasma resulted in the most robust biofilms in all six strains. The enzymes α-amylase, bromelain, lysostaphin, and papain were then tested against S. aureus biofilms cultured in 10% human plasma. Quantification of biofilms after 2 hours and 24 hours of treatment using the crystal violet assay revealed that lysostaphin decreased biomass by up to 76%, whereas α-amylase, bromelain, and papain reduced biomass by up to 97%, 98%, and 98%, respectively. Scanning electron microscopy confirmed that the dispersal agents detached the biofilm exopolysaccharide matrix and bacteria from the growth surface. Lysostaphin caused less visible dispersal of the biofilms, but unlike the other enzymes, induced morphological changes indicative of bacterial cell damage. Overall, our results indicate that use of enzymes may be an effective means of eradicating biofilms and a promising strategy to improve treatment of multidrug-resistant bacterial infections.

  5. Enzymatic degradation of in vitro Staphylococcus aureus biofilms supplemented with human plasma

    Directory of Open Access Journals (Sweden)

    Watters CM

    2016-04-01

    Full Text Available Chase M Watters,1,2 Tarea Burton,1 Dickson K Kirui,1 Nancy J Millenbaugh1 1Maxillofacial Injury and Disease Department, Naval Medical Research Unit San Antonio, Joint Base San Antonio-Fort Sam Houston, TX, USA; 2Wound Infections Department, Naval Medical Research Center, Silver Spring, MD, USA Abstract: Enzymatic debridement is a therapeutic strategy used clinically to remove necrotic tissue from wounds. Some of the enzymes utilized for debridement have been tested against bacterial pathogens, but the effectiveness of these agents in dispersing clinically relevant biofilms has not been fully characterized. Here, we developed an in vitro Staphylococcus aureus biofilm model that mimics wound-like conditions and employed this model to investigate the antibiofilm activity of four enzymatic compounds. Human plasma at concentrations of 0%–50% was supplemented into growth media and used to evaluate biofilm biomass accumulation over 24 hours and 48 hours in one methicillin-sensitive and five methicillin-resistant strains of S. aureus. Supplementation of media with 10% human plasma resulted in the most robust biofilms in all six strains. The enzymes α-amylase, bromelain, lysostaphin, and papain were then tested against S. aureus biofilms cultured in 10% human plasma. Quantification of biofilms after 2 hours and 24 hours of treatment using the crystal violet assay revealed that lysostaphin decreased biomass by up to 76%, whereas a-amylase, bromelain, and papain reduced biomass by up to 97%, 98%, and 98%, respectively. Scanning electron microscopy confirmed that the dispersal agents detached the biofilm exopolysaccharide matrix and bacteria from the growth surface. Lysostaphin caused less visible dispersal of the biofilms, but unlike the other enzymes, induced morphological changes indicative of bacterial cell damage. Overall, our results indicate that use of enzymes may be an effective means of eradicating biofilms and a promising strategy to improve

  6. Misidentification of methicillin-resistant Staphylococcus aureus (MRSA in hospitals in Tripoli, Libya

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    Mohamed O. Ahmed

    2010-11-01

    Full Text Available Background: Methicillin-resistant Staphylococcus aureus (MRSA is a nosocomial (hospital-acquired pathogen of exceptional concern. It is responsible for life-threatening infections in both the hospital and the community. Aims: To determine the frequency of MRSA misidentification in hospitals in Tripoli, Libya using current testing methods. Methods: One hundred and seventy S. aureus isolates previously identified as MRSA were obtained from three hospitals in Tripoli. All isolates were reidentified by culturing on mannitol salt agar, API 20 Staph System and retested for resistance to methicillin using the cefoxitin disk diffusion susceptibility test and PBP2a. D-tests and vancomycin E-tests (Van-E-tests were also performed for vancomycin-resistant isolates. Results: Of the 170 isolates examined, 86 (51% were confirmed as MRSA (i.e. 49% were misidentified as MRSA. Fifteen (17% of the confirmed MRSA strains exhibited inducible clindamycin resistance. Of the 86 confirmed MRSA isolates, 13 (15% were resistant to mupirocin, 53 (62% were resistant to ciprofloxacin, 41 (48% were resistant to trimethoprim-sulfamethoxazole, and none were resistant to linezolid. Although disc-diffusion testing indicated that 23 (27% of the isolates were resistant to vancomycin, none of the isolates were vancomycin-resistant by Van-E-test. Conclusions: Misidentification of nosocomial S. aureus as MRSA is a serious problem in Libyan hospitals. There is an urgent need for the proper training of microbiology laboratory technicians in standard antimicrobial susceptibility procedures and the implementation of quality control programs in microbiology laboratories of Libyan hospitals.

  7. First report of sasX-positive methicillin-resistant Staphylococcus aureus in Japan.

    Science.gov (United States)

    Nakaminami, Hidemasa; Ito, Teruyo; Han, Xiao; Ito, Ayumu; Matsuo, Miki; Uehara, Yuki; Baba, Tadashi; Hiramatsu, Keiichi; Noguchi, Norihisa

    2017-09-01

    SasX is a known virulence factor of Staphylococcus aureus involved in colonisation and immune evasion of the bacterium. The sasX gene, which is located on the ϕSPβ prophage, is frequently found in the sequence type (ST) 239 S. aureus lineage, which is the predominant healthcare-associated clone in Asian countries. In Japan, ST239 clones have rarely been identified, and sasX-positive strains have not been reported to date. Here, we report the first identification of 18 sasX-positive methicillin-resistant S. aureus (MRSA) strains in Japanese hospitals between 2009 and 2011. All sasX-positive isolates belonged to an ST239-staphylococcal cassette chromosome mec type III (ST239-III) lineage. However, we were unable to identify additional sasX-positive MRSA strains from 2012 to 2016, indicating that the small epidemic of sasX-positive isolates observed in this study was temporary. The sequence surrounding sasX in the strain TOHH628 lacked 51 genes that encode phage packaging and structural proteins, and no bacteriophage was induced by mitomycin C. Additionally, in the TOHH628 strain, the region (64.6 kb) containing sasX showed high identity to the ϕSPβ-like element (71.3 kb) of the Taiwanese MRSA strain Z172. The data strongly suggest that the present sasX-positive isolates found in Japanese hospitals were transmitted incidentally from other countries. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Effect of whole Staphylococcus aureus and mode of immunization on bovine opsonizing antibodies to capsule.

    Science.gov (United States)

    Guidry, A J; O'Brien, C N; Oliver, S P; Dowlen, H H; Douglass, L W

    1994-10-01

    Exopolysaccharide capsule is a major virulence factor of Staphylococcus aureus because it inhibits neutrophil recognition of antibodies to highly antigenic S. aureus cell wall. To circumvent this inhibition, two modes of immunization were tested for ability to induce anticapsular opsonins. Cows were immunized at drying off and boosted on d 14 and 28 by injection of Smith diffuse S. aureus plus dextran sulfate in the area of the supramammary lymph node or intramammarily. In cows immunized in the area of the supramammary lymph node, IgG1 and IgG2 sera antibody titers to capsule increased and remained elevated to the end of the study, 120 d postcalving. The IgM titers increased during the dry period but declined to preimmunization levels at calving. Response of serum IgG1 and IgM to intramammary immunization was similar to that with supramammary lymph node immunization, but more delayed and lower in magnitude. Antibodies of all four isotypes, IgG1, IgG2, IgA, and IgM, increased in dry secretions following immunization via lymph node. In cows immunized in the lymph node, IgG1 antibodies remained elevated throughout the study, but IgG2 antibodies dropped to baseline 15 d postcalving. In cows immunized intramammarily, only IgA antibodies increased significantly in lacteal secretions and remained elevated throughout the study. Immunization of cows in the lymph node during the dry period enhanced the ability of dry secretions and colostrum to support phagocytosis.

  9. Misidentification of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals in Tripoli, Libya

    Science.gov (United States)

    Ahmed, Mohamed O.; Abuzweda, Abdulbaset R.; Alghazali, Mohamed H.; Elramalli, Asma K.; Amri, Samira G.; Aghila, Ezzeddin Sh.; Abouzeed, Yousef M.

    2010-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial (hospital-acquired) pathogen of exceptional concern. It is responsible for life-threatening infections in both the hospital and the community. Aims To determine the frequency of MRSA misidentification in hospitals in Tripoli, Libya using current testing methods. Methods One hundred and seventy S. aureus isolates previously identified as MRSA were obtained from three hospitals in Tripoli. All isolates were reidentified by culturing on mannitol salt agar, API 20 Staph System and retested for resistance to methicillin using the cefoxitin disk diffusion susceptibility test and PBP2a. D-tests and vancomycin E-tests (Van-E-tests) were also performed for vancomycin-resistant isolates. Results Of the 170 isolates examined, 86 (51%) were confirmed as MRSA (i.e. 49% were misidentified as MRSA). Fifteen (17%) of the confirmed MRSA strains exhibited inducible clindamycin resistance. Of the 86 confirmed MRSA isolates, 13 (15%) were resistant to mupirocin, 53 (62%) were resistant to ciprofloxacin, 41 (48%) were resistant to trimethoprim-sulfamethoxazole, and none were resistant to linezolid. Although disc-diffusion testing indicated that 23 (27%) of the isolates were resistant to vancomycin, none of the isolates were vancomycin-resistant by Van-E-test. Conclusions Misidentification of nosocomial S. aureus as MRSA is a serious problem in Libyan hospitals. There is an urgent need for the proper training of microbiology laboratory technicians in standard antimicrobial susceptibility procedures and the implementation of quality control programs in microbiology laboratories of Libyan hospitals. PMID:21483574

  10. Radioimmunoassays for protein A of Staphylococcus aureus

    Energy Technology Data Exchange (ETDEWEB)

    Langone, J.J.; Das, C.; Bennett, D.; Terman, D.S. (Baylor Univ., Houston, TX (USA). Coll. of Medicine)

    1983-10-14

    Radioimmunoassays have been developed that can detect nanogram amounts of protein A (SpA), a product generated by Staphylococcus aureus that binds selectively to the Fc region of IgG from most mammalian species. Competition assays for fluid phase SpA utilize antibodies produced in chickens, /sup 125/I-labeled SpA as the tracer molecule, and either F(ab')/sub 2/ fragments of rabbit IgG anti-chicken IgG or 40% ammonium sulfate as the precipitating agent to separate antigen-antibody complexes from free antigen. The double antibody assay could be carried out in serum from species that form only soluble complexes with SpA (e.g., rabbit), that react poorly with SpA (e.g., rat) or under appropriate conditions in serum from species (e.g., dog) that show high reactivity with SpA and form precipitating complexes. Chicken antibodies prepared by affinity chromatography on SpA-Sepharose and labeled with /sup 125/I were used in a direct binding assay for SpA present either on the cell wall of Cowan strain I or Wood 46 bacteria, in insoluble complexes prepared from SpA and whole serum or purified IgG, or in C1q binding complexes that were formed by passage of serum from normal or tumor bearing humans or dogs over SpA-collodion charcoal. Since both types of assays could detect SpA even in the presence of serum or IgG, they offer advantages over other techniques in which the SpA-Fc interaction may interfere.

  11. Occurrence and distribution of Staphylococcus aureus lineages among zoo animals

    DEFF Research Database (Denmark)

    Gongora, Carmen Espinosa; Chrobak, Dorota; Moodley, Arshnee

    2012-01-01

    The current knowledge of the occurrence and diversity of Staphylococcus aureus in animals is largely biased in favour MRSA and domestic animals. In order to generate novel information on the ecology and population structure of this bacterial species in the animal kingdom, we investigated the occu...... MSSA belonging to fourteen spa types, including three novel spa types. MLST revealed the occurrence of seven STs. The study of the ecology of commensal S. aureus in captive wild animals revealed that ST133 has a broader host range than previously thought.......The current knowledge of the occurrence and diversity of Staphylococcus aureus in animals is largely biased in favour MRSA and domestic animals. In order to generate novel information on the ecology and population structure of this bacterial species in the animal kingdom, we investigated...... the occurrence and genotypic diversity of S. aureus in a range of animal species kept at the Copenhagen Zoo. We sampled 146 animals belonging to 25 mammalian species and 21 reptiles belonging to six species. A total of 59 S. aureus isolates were found in 10 of the 25 mammalian species tested. All isolates were...

  12. Role of nasal carriage of Staphylococcus aureus in chronic urticaria

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    Ashimav Deb Sharma

    2012-01-01

    Full Text Available Aim: To evaluate the role of nasal carriage of Staphylococcus aureus in patients suffering from chronic urticaria. Method: All total 82 patients were included for this study. Study group comprised 57 patients with chronic urticaria and the control group comprised 25 healthy volunteers. Nasal swab specimens were taken from all the 82 patients for bacterial culture and antimicrobial sensitivity. Patients with chronic urticaria who had positive growth for S. aureus were treated with sensitive antimicrobial agent. Nasal swab specimens were taken again from all the patients who received antimicrobial therapy to ensure complete eradication of S. aureus. All patients were followed up for a period of 6 weeks after the treatment. Urticarial activity was measured with the help of urticarial activity score. Results: S. aureus was detected in swab specimens from the nasal cavity in 32 patients in the study group and 7 patients in the control group. In the study group, after the antimicrobial treatment, 9 patients (28.12% had complete recovery from urticaria during the follow-up period; 4 patients (12.5% showed partial recovery from urticaria while the remaining patients (59.37% continued to suffer from urticaria. Conclusion: This study showed that nasal carriage of S. aureus can act as an etiological factor in chronic urticaria.

  13. Prevalence of Salmonella and Staphylococcus aureus in chorizo and longaniza

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    Refugio Torres-Vitela

    2011-12-01

    Full Text Available Epidemiological research in developed and developing countries, had found meat products as the principal cause for foodbourne diseases. In addition, Salmonella and Staphyococcus aureus are well known pathogens for their mayor impact in public health. The objective for the present study consisted on determinate the sanitary quality from chorizo and longaniza samples from several butcheries in Guadalajara, Jalisco, Mexico. Samples of chorizo (50 and longaniza (50 were obtained from different points in Guadalajara metropolis. Presence of Salmonella and recounts for S. aureus were tested in 25 g samples. Procedure was followed according Mexican NOM 145-SSA1-1995 methods. In chorizo, 18 samples were positive to Salmonella. The count of S. aureus showed a mean of 24,600 UFC/g. On the other hand, 24 samples of longaniza were positive to Salmonella spp. In this case, the mean of S. aureus was 7,800 UFC/g. The serotypes of Salmonella spp were: Derby (30%, Adelaile (17%, Azteca (15%, Infantis (15%, Muenster(10% y Anatum (13 %. The high positivity of Salmonella spp. and S. aureus is a potential hazard to consumers.

  14. The Bicomponent Pore-Forming Leucocidins of Staphylococcus aureus

    Science.gov (United States)

    Alonzo, Francis

    2014-01-01

    SUMMARY The ability to produce water-soluble proteins with the capacity to oligomerize and form pores within cellular lipid bilayers is a trait conserved among nearly all forms of life, including humans, single-celled eukaryotes, and numerous bacterial species. In bacteria, some of the most notable pore-forming molecules are protein toxins that interact with mammalian cell membranes to promote lysis, deliver effectors, and modulate cellular homeostasis. Of the bacterial species capable of producing pore-forming toxic molecules, the Gram-positive pathogen Staphylococcus aureus is one of the most notorious. S. aureus can produce seven different pore-forming protein toxins, all of which are believed to play a unique role in promoting the ability of the organism to cause disease in humans and other mammals. The most diverse of these pore-forming toxins, in terms of both functional activity and global representation within S. aureus clinical isolates, are the bicomponent leucocidins. From the first description of their activity on host immune cells over 100 years ago to the detailed investigations of their biochemical function today, the leucocidins remain at the forefront of S. aureus pathogenesis research initiatives. Study of their mode of action is of immediate interest in the realm of therapeutic agent design as well as for studies of bacterial pathogenesis. This review provides an updated perspective on our understanding of the S. aureus leucocidins and their function, specificity, and potential as therapeutic targets. PMID:24847020

  15. Virulence potential of Staphylococcus aureus isolates from Buruli ulcer patients.

    Science.gov (United States)

    Amissah, Nana Ama; Chlebowicz, Monika A; Ablordey, Anthony; Tetteh, Caitlin S; Prah, Isaac; van der Werf, Tjip S; Friedrich, Alex W; van Dijl, Jan Maarten; Stienstra, Ymkje; Rossen, John W

    2017-06-01

    Buruli ulcer (BU) is a necrotizing infection of the skin and subcutaneous tissue caused by Mycobacterium ulcerans. BU wounds may also be colonized with other microorganisms including Staphylococcus aureus. This study aimed to characterize the virulence factors of S. aureus isolated from BU patients. Previously sequenced genomes of 21 S. aureus isolates from BU patients were screened for the presence of virulence genes. The results show that all S. aureus isolates harbored on their core genomes genes for known virulence factors like α-hemolysin, and the α- and β-phenol soluble modulins. Besides the core genome virulence genes, mobile genetic elements (MGEs), i.e. prophages, genomic islands, pathogenicity islands and a Staphylococcal cassette chromosome (SCC) were found to carry different combinations of virulence factors, among them genes that are known to encode factors that promote immune evasion, superantigens and Panton-Valentine Leucocidin. The present observations imply that the S. aureus isolates from BU patients harbor a diverse repertoire of virulence genes that may enhance bacterial survival and persistence in the wound environment and potentially contribute to delayed wound healing. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  16. A systematic review of animal models for Staphylococcus aureus osteomyelitis

    Science.gov (United States)

    Reizner, W.; Hunter, J.G.; O’Malley, N.T.; Southgate, R.D.; Schwarz, E.M.; Kates, S.L.

    2015-01-01

    Staphylococcus aureus (S. aureus) osteomyelitis is a significant complication for orthopaedic patients undergoing surgery, particularly with fracture fixation and arthroplasty. Given the difficulty in studying S. aureus infections in human subjects, animal models serve an integral role in exploring the pathogenesis of osteomyelitis, and aid in determining the efficacy of prophylactic and therapeutic treatments. Animal models should mimic the clinical scenarios seen in patients as closely as possible to permit the experimental results to be translated to the corresponding clinical care. To help understand existing animal models of S. aureus, we conducted a systematic search of PubMed & Ovid MEDLINE to identify in vivo animal experiments that have investigated the management of S. aureus osteomyelitis in the context of fractures and metallic implants. In this review, experimental studies are categorized by animal species and are further classified by the setting of the infection. Study methods are summarized and the relevant advantages and disadvantages of each species and model are discussed. While no ideal animal model exists, the understanding of a model’s strengths and limitations should assist clinicians and researchers to appropriately select an animal model to translate the conclusions to the clinical setting. PMID:24668594

  17. Frequency of methicillin resistant Staphylococcus aureus in health care

    Directory of Open Access Journals (Sweden)

    Somayeh Rahimi-Alang

    2011-03-01

    Full Text Available Background: Methicillin resistant Staphylococcus aureus (MRSA is one of the most important pathogen in hospitals. Healthcare personnel are the main source of nosocomial infections and identification and control of MRSA carriers can reduce incidence of infections. The aim of this study was to determine the prevalence of MRSA and their antibiotic susceptibility profile among healthcare workers in Gorgan.Materials and Method: 333 healthcare workers were participated in this cross-sectional study in 2009. Samples were taken with sterile cotton swabs from both anterior nares and hands. Swabs were plated immediately on to the mannitol salt agar. Suspected colonies were confirmed as S. aureus by Gram staining, catalase, coagulase and DNase tests. Minimum inhibition concentration by micro dilution broth method was used to determine methicillin resistant strains. Antimicrobial susceptibility to other antibiotics was performed according to NCCLS guidelines by disc diffusion method.Result: Frequency of S.aureus and MRSA carriers among healthcare workers was 24% and 3% respectively. The highest rate of S. aureus and MRSA carriers were observed in operating room staff. Resistance to penicillin was seen in 97.5% of isolates and all strains were sensitive to vancomycin.Conclusions: Frequency of S. aureus and MRSA in healthcare workers was median and rather low respectively. Continual monitoring and control of carriers can reduce distribution of this organism and their infections

  18. Prevalence of Staphylococcus aureus in Shrimps in Tehran during 2013

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Soltan Dallal

    2016-02-01

    Full Text Available Background During fishing and transport, preservation and quality of fish products are importantas well as storage to prevent the growth of pathogenic and toxin producing bacteria.Staphylococcus aureus is one of the most common causes of sea food-borne diseases worldwidedue to contamination of food by preformed enterotoxins. The aim of this study was to compare theprevalence and contamination of S. aureus in marine and farmed shrimps in Tehran fishery center.Methods: A total of 300 samples, including 150 marine, 150 farmed shrimps were selected duringSeptember 2013 to December 2014. Isolation and identification of S. aureus from isolated sampleswere carried out according to conventional methods, and antibiotic susceptibility test wasperformed by modified Kirby-Bauer disc diffusion method.Results: The results of this study showed that 30% of marine and 20% off armed shrimps werecontaminated with S. aureus. The highest resistance was observed with penicillin and ampicillin,whereas 100% were sensitive to vancomycin, clindamycin, ciprofloxacin, and rifampin.Conclusions: Due to relatively high contamination of shrimp by S. aureus more attention shouldbe given during processing and manufacturing.

  19. Staphylococcus aureus isolated from tonsillectomized adult patients with recurrent tonsillitis.

    Science.gov (United States)

    Katkowska, Marta; Garbacz, Katarzyna; Stromkowski, Józef

    2017-01-01

    The aim of this study was to analyze the prevalence and antibiotic resistance of Staphylococcus aureus strains from 118 tonsillectomized adults due to recurrent tonsillitis (RT). The study included strains isolated from the tonsillar surface prior to tonsillectomy, recovered from the tonsillar core at the time of surgery, and from the posterior throat 2-4 weeks after the procedure. Susceptibility of isolates to 19 antibiotics was tested in line with the Clinical and Laboratory Standards Institute recommendations. Irrespective of the stage, the most commonly isolated bacteria were gram-positive cocci, and among them S. aureus. The tonsillar core was the most common site of S. aureus isolation (30.5%), followed by the tonsillar surface (10.8%) and the posterior pharynx (5.9%). This difference turned out to be statistically significant (p Staphylococcus aureus seems to be the most common pathogen isolated from patients tonsillectomized due to RT. Staphylococcal isolates associated with RT are present mostly within the tonsillar core and susceptible to most antibiotics. They are typically isolated from patients between 21 and 30 years of age. Tonsillectomy results in less frequent isolation of S. aureus strains. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  20. Antibacterial Action of Curcumin against Staphylococcus aureus: A Brief Review

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    Sin-Yeang Teow

    2016-01-01

    Full Text Available Curcumin, the major constituent of Curcuma longa L. (Zingiberaceae family or turmeric, commonly used for cooking in Asian cuisine, is known to possess a broad range of pharmacological properties at relatively nontoxic doses. Curcumin is found to be effective against Staphylococcus aureus (S. aureus. As demonstrated by in vitro experiment, curcumin exerts even more potent effects when used in combination with various other antibacterial agents. Hence, curcumin which is a natural product derived from plant is believed to have profound medicinal benefits and could be potentially developed into a naturally derived antibiotic in the future. However, there are several noteworthy challenges in the development of curcumin as a medicine. S. aureus infections, particularly those caused by the multidrug-resistant strains, have emerged as a global health issue and urgent action is needed. This review focuses on the antibacterial activities of curcumin against both methicillin-sensitive S. aureus (MSSA and methicillin-resistant S. aureus (MRSA. We also attempt to highlight the potential challenges in the effort of developing curcumin into a therapeutic antibacterial agent.

  1. Prevalence of Staphylococcus aureus in Shrimps in Tehran during 2013

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Soltan Dallal

    2015-12-01

    Full Text Available Background During fishing and transport, preservation and quality of fish products are importantas well as storage to prevent the growth of pathogenic and toxin producing bacteria.Staphylococcus aureus is one of the most common causes of sea food-borne diseases worldwidedue to contamination of food by preformed enterotoxins. The aim of this study was to compare theprevalence and contamination of S. aureus in marine and farmed shrimps in Tehran fishery center.Methods: A total of 300 samples, including 150 marine, 150 farmed shrimps were selected duringSeptember 2013 to December 2013. Isolation and identification of S. aureus from isolated sampleswere carried out according to conventional methods, and antibiotic susceptibility test wasperformed by modified Kirby-Bauer disc diffusion methodResults: The results of this study showed that 30% of marine and 20% off armed shrimps werecontaminated with S. aureus. The highest resistance was observed with penicillin and ampicillin,whereas 100% were sensitive to vancomycin, clindamycin, ciprofloxacin, and rifampin.Conclusions: Due to relatively high contamination of shrimp by S. aureus more attention shouldbe given during processing and manufacturing.

  2. Utility of (11)C-methionine and (11)C-donepezil for imaging of Staphylococcus aureus induced osteomyelitis in a juvenile porcine model: comparison to autologous (111)In-labelled leukocytes, (99m) Tc-DPD, and (18)F-FDG

    DEFF Research Database (Denmark)

    Afzelius, Pia; Alstrup, Aage K.O.; Schønheyder, Henrik C

    2016-01-01

    The aim of this study was to compare (11)C-methionine and (11)C-donepezil positron emission tomography (PET) with (111)In-labeled leukocyte and (99m) Tc-DPD (Tc-99m 3,3-diphosphono-1,2-propanedicarboxylic acid) single-photon emission computed tomography (SPECT), and (18)F-fluorodeoxyglucose ((18)F...... in the right femoral artery with a porcine strain of Staphylococcus aureus. The sequential scan protocol included Computed Tomography, (11)C-methionine and (11)C-donepezil PET, (99m) Tc-DPD and (111)In-labelled leukocytes scintigraphy, and (18)F-FDG PET. This was followed by necropsy of the pigs and gross......-methionine in 79%, (11)C-donepezil in 58%, and (99m) Tc-DPD in none. Overall, (18)F-FDG PET was superior to (111)In-leukocyte SPECT and (11)C-methionine in marking infectious lesions....

  3. Antimicrobial resistance of Staphylococcus aureus isolates from dairy cows and genetic diversity of resistant isolates

    Science.gov (United States)

    Staphylococcus aureus is a frequent and major contagious mastitis bacterial pathogen. The antibiotic treatment cure rates vary considerably from 4% to 92%. Staphylococcus aureus readily becomes resistant to antibiotics, resulting in persistent noncurable intramammary infection that usually results i...

  4. Mupirocin prophylaxis against nosocomial Staphylococcus aureus infections in nonsurgical patients: a randomized study

    NARCIS (Netherlands)

    M.C. Vos (Margreet); A. Ott (Alewijn); A. Voss (Andreas); J.A.J.W. Kluytmans (Jan); C.M.J.E. Vandenbroucke-Grauls (Christina); M.H.M. Meester (Marlene); P.H.J. van Keulen (Peter); H.A. Verbrugh (Henri); H.F.L. Wertheim (Heiman)

    2004-01-01

    textabstractBACKGROUND: Staphylococcus aureus nasal carriage is a major risk factor for nosocomial S. aureus infection. Studies show that intranasal mupirocin can prevent nosocomial surgical site infections. No data are available on the efficacy of mupirocin in nonsurgical

  5. Molecular and mathematical epidemiology of Staphylococcus aureus and Streptococcus uberis mastitis in dairy herds

    NARCIS (Netherlands)

    Zadoks, Ruth Nicolet

    2002-01-01

    Mastitis is the most common and costly production disease affecting dairy cows. Staphylococcus aureus and Streptococcus uberis are two major mastitis-causing pathogens. Staphylococcus aureus is traditionally classified as contagious pathogen, while Streptococcus uberis is classified as environmental

  6. Staphylococcus aureus strains in primiparous and multiparous cows in six herds with a high prevalence of Staph. aureus intramammary infections.

    Science.gov (United States)

    Tenhagen, Bernd-Alois; Scheibe, Nicole; Zucker, Bert-Andree; Köster, Gudrun; Heuwieser, Wolfgang

    2007-11-01

    The proportion of different strains of Staphylococcus aureus was tested in four groups of lactating dairy cows in six herds with a high overall prevalence of Staph. aureus using random amplified polymorphic DNA PCR. Group 1 included primiparous cows in early lactation (250 days in milk). Groups 3 and 4 were multiparous cows in the respective stages of lactation. Eight cows from each group on each farm were tested. Overall quarter prevalence of Staph. aureus ranged from 23.4 to 32.0% in the herds. Of the 130 isolates included in the analysis 86.9% were high prevalence strains (more than three isolates per herd), while 13.1% were strains that were only identified in one or two samples. Low prevalence strains were found in all six herds. The proportion of low prevalence strains was higher in multiparous than in primiparous cows (odds ratio, OR 4.4, 1.2-16.6). It is concluded that low prevalence Staph. aureus strains are common even in herds with a high prevalence of Staph. aureus and that their frequency is lower in primiparous cows than in older cows.

  7. Antibiotic Combinations with Daptomycin for Treatment of Staphylococcus aureus Infections

    Directory of Open Access Journals (Sweden)

    Kristina Nadrah

    2011-01-01

    Full Text Available Daptomycin is a lipopeptide antibiotic with a unique mechanism of action on Gram-positive bacteria. It is approved for treatment of skin and soft-tissue infections with Gram-positive bacteria, bacteraemia and right-sided infective endocarditis caused by Staphylococcus aureus. Diminishing susceptibility of S. aureus to daptomycin during treatment of complicated infections and clinical failure have been described. Combinations of daptomycin with other antibiotics including gentamicin, rifampin, beta-lactams, trimethoprim/sulfamethoxazole (TMP-SMX, or clarithromycin present a new approach for therapy. In vitro and animal studies have shown that such combinations may, in some cases, be superior to daptomycin monotherapy. In this paper we focus on the antibiotic combinations for complicated S. aureus infections.

  8. Staphylococcus aureus biofilms: recent developments in biofilm dispersal.

    Science.gov (United States)

    Lister, Jessica L; Horswill, Alexander R

    2014-01-01

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and represents a significant burden on the healthcare system. S. aureus attachment to medical implants and host tissue, and the establishment of a mature biofilm, play an important role in the persistence of chronic infections. The formation of a biofilm, and encasement of cells in a polymer-based matrix, decreases the susceptibility to antimicrobials and immune defenses, making these infections difficult to eradicate. During infection, dispersal of cells from the biofilm can result in spread to secondary sites and worsening of the infection. In this review, we discuss the current understanding of the pathways behind biofilm dispersal in S. aureus, with a focus on enzymatic and newly described broad-spectrum dispersal mechanisms. Additionally, we explore potential applications of dispersal in the treatment of biofilm-mediated infections.

  9. Staphylococcus aureus Transcriptome Architecture

    DEFF Research Database (Denmark)

    Mäder, Ulrike; Nicolas, Pierre; Depke, Maren

    2016-01-01

    antisense RNAs not co-transcribed with other genes were found. Promoter analysis and comparison with Bacillus subtilis links the small number of antisense RNAs to a less profound impact of alternative sigma factors in S. aureus. Furthermore, we revealed that Rho-dependent transcription termination....... aureus HG001, a derivative of strain NCTC 8325, across experimental conditions ranging from optimal growth in vitro to intracellular growth in host cells. These data establish an extensive repertoire of transcription units and non-coding RNAs, a classification of 1412 promoters according...... to their dependence on the RNA polymerase sigma factors SigA or SigB, and allow identification of new potential targets for several known transcription factors. In particular, this study revealed a relatively low abundance of antisense RNAs in S. aureus, where they overlap only 6% of the coding genes, and only 19...

  10. Biochemical Characterization of Lysine Auxotrophs of Staphylococcus aureus1

    Science.gov (United States)

    Barnes, Isabel J.; Bondi, Amedeo; Moat, Albert G.

    1969-01-01

    Lysine biosynthesis in Staphylococcus aureus has been studied by use of a series of lysine auxotrophs. The strains were isolated after chemical mutagenesis. The majority of these mutant strains were classified according to the enzymatic step found to be deficient. Specific enzyme assays as well as nutritional tests were used to group the organisms. The enzymes included were dihydrodipicolinate synthetase, dihydrodipicolinate reductase, diaminopimelate epimerase, and diaminopimelate decarboxylase. The accumulation of diaminopimelate in certain mutants and the demonstration of dihydrodipicolinate synthetase and reductase provide the first detailed evidence that S. aureus utilizes the diaminopimelate pathway for lysine biosynthesis. A cell-free system was used to study the regulation of these enzymes with the exception of diaminopimelate epimerase. Lysine repressed all of the enzymes tested. The repression appeared to be coordinate in nature. The data presented provide suggestive evidence that the lysine biosynthetic region in S. aureus constitutes an operon. PMID:5802602

  11. Pesquisa de Staphylococcus aureus em leite a ser pasteurizado Staphylococcus aureus in milk before pasteurinzing

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    Donald Wilson

    1977-03-01

    Full Text Available Estuda-se a contaminação por S. aureus do leite a ser pasteurizado, demonstrando que está altamente contaminado. São discutidas as conseqüências que a contaminação pode ter e conclui-se serem necessárias medidas urgentes para alterar a estrutura epidemiológica da "linha de leite".The present paper is a study on Staphylococcal contamination of milk before pasteurizing. Gross contamination is shown, and possible consequences are discussed. That measures intended to alter the epidemiologic structure of the so called milk line are necessary and urgent, is the final conclusion of the paper.

  12. Highly sensitive detection of Staphylococcus aureus directly from patient blood.

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    Padmapriya P Banada

    Full Text Available Rapid detection of bloodstream infections (BSIs can be lifesaving. We investigated the sample processing and assay parameters necessary for highly-sensitive detection of bloodstream bacteria, using Staphylococcus aureus as a model pathogen and an automated fluidic sample processing-polymerase chain reaction (PCR platform as a model diagnostic system.We compared a short 128 bp amplicon hemi-nested PCR and a relatively shorter 79 bp amplicon nested PCR targeting the S. aureus nuc and sodA genes, respectively. The sodA nested assay showed an enhanced limit of detection (LOD of 5 genomic copies per reaction or 10 colony forming units (CFU per ml blood over 50 copies per reaction or 50 CFU/ml for the nuc assay. To establish optimal extraction protocols, we investigated the relative abundance of the bacteria in different components of the blood (white blood cells (WBCs, plasma or whole blood, using the above assays. The blood samples were obtained from the patients who were culture positive for S. aureus. Whole blood resulted in maximum PCR positives with sodA assay (90% positive as opposed to cell-associated bacteria (in WBCs (71% samples positive or free bacterial DNA in plasma (62.5% samples positive. Both the assays were further tested for direct detection of S. aureus in patient whole blood samples that were contemporaneous culture positive. S. aureus was detected in 40/45 of culture-positive patients (sensitivity 89%, 95% CI 0.75-0.96 and 0/59 negative controls with the sodA assay (specificity 100%, 95% CI 0.92-1.We have demonstrated a highly sensitive two-hour assay for detection of sepsis causing bacteria like S. aureus directly in 1 ml of whole blood, without the need for blood culture.

  13. Effect of lactic acid bacteria on growth of Staphylococcus aureus.

    Science.gov (United States)

    Kao, C T; Frazier, W C

    1966-03-01

    Cultures of lactic acid bacteria, mostly from foods, were tested for their effect on the growth of Staphylococcus aureus in Trypticase Soy Broth (BBL). Some of the effectors, e.g., Streptococcus faecalis, S. faecium, Lactobacillus lactis, L. brevis, and Leuconostoc mesenteroides, stimulated growth of S. aureus during early hours of growth, especially at higher temperatures of incubation, but most cultures were inhibitory, and some (S. faecium and L. mesenteroides) were even killing by the time of attainment of the maximal phase of growth of the Staphylococcus. Low-temperature meat lactobacilli and Leuconostoc dextranicum inhibited S. aureus at 10, 15, 20, and 25 C throughout its growth. Streptococcus faecalis var. liquefaciens inhibited at these temperatures and at 30 and 37 C, as well. When the ratio of effectors to staphylococci in the inoculum was 100:1, the three enterococci, the meat Lactobacillus, and L. dextranicum prevented the attainment of 5 x 10(6) staphylococci per milliliter at 15 C, and all but the meat Lactobacillus did so at 22 C. A ratio of 1:1 accomplished similar results at 15 C, except that S. aureus was only delayed for 12 hr by S. faecalis. A ratio of 1:100 usually was ineffective. In general, the more effector bacteria there were in the inoculum, the greater was the overall inhibition (or stimulation) of S. aureus. Inhibition was most effective at 10 or 15 C, less so at 20 or 25 C, and least at 30 or 37 C, whereas stimulation during early growth was greater at the higher temperatures. Results with different strains of the effectors and with two strains of S. aureus were similar, for the most part.

  14. New epidemiology of Staphylococcus aureus infection in Asia.

    Science.gov (United States)

    Chen, C-J; Huang, Y-C

    2014-07-01

    Not only is Asia the most populous region in the world, but inappropriate therapy, including self-medication with over-the-counter antimicrobial agents, is a common response to infectious diseases. The high antibiotic selective pressure among the overcrowded inhabitants creates an environment that is suitable for the rapid development and efficient spread of numerous multidrug-resistant pathogens. Indeed, Asia is among the regions with the highest prevalence rates of healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-associated methicillin-resistant S. aureus (CA-MRSA) in the world. Most hospitals in Asia are endemic for multidrug-resistant methicillin-resistant S. aureus (MRSA), with an estimated proportion from 28% (in Hong Kong and Indonesia) to >70% (in Korea) among all clinical S. aureus isolates in the early 2010s. Isolates with reduced susceptibility or a high level of resistance to glycopeptides have also been increasingly identified in the past few years. In contrast, the proportion of MRSA among community-associated S. aureus infections in Asian countries varies markedly, from 35%. Two pandemic HA-MRSA clones, namely multilocus sequence type (ST) 239 and ST5, are disseminated internationally in Asia, whereas the molecular epidemiology of CA-MRSA in Asia is characterized by clonal heterogeneity, similar to that in Europe. In this review, the epidemiology of S. aureus in both healthcare facilities and communities in Asia is addressed, with an emphasis on the prevalence, clonal structure and antibiotic resistant profiles of the MRSA strains. The novel MRSA strains from livestock animals have been considered to constitute a public health threat in western countries. The emerging livestock-associated MRSA strains in Asia are also included in this review. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

  15. UJI BIOAKTIVITAS FORBAZOL E TERHADAP HAMBATAN PERTUMBUHAN PADA STAPHYLOCOCCUS AUREUS

    Directory of Open Access Journals (Sweden)

    Ni Putu Ristiati

    2015-05-01

    Full Text Available Forbazol E dapat disintesis dari 1-(p-tosil pirol-2-karbonil klorida dan fenasil amonium klorida dengan rendeman cukup tinggi melalui empat tahap reaksi yaitu : pertama, reaksi penggabungan; kedua, siklodehidrasi; ketiga,hidrolisis; dan keempat, klorinasi. Staphylococcus aureus merupakan bakteri gram positif. Untuk itu perlu diteliti : (a forbazol E dapat menghambat pertumbuhan S. aureus ; (b konsentrasi forbazol E 75 mg/L akan menimbulkan hambatan pertumbuhan S. aureus lebih tinggi dari konsentrasi 37,5 mg/L. Penelitian eksperimental ini menggunakan rancangan the randomized- posttest-only control group design dan melibatkan 9 sampel pada kelompok kontrol, 9 sampel pada kelompok perlakuan I dan 9 sampel pada perlakuan II. Data yang diperoleh dianalisis dengan menggunakan uji anova pada taraf signifikansi 5%. Hasil penelitian membuktikan forbazol E dapat menghambat pertumbuhan, pemberian  forbazol E pada  pada kelompok perlakuan II dengan konsentrasi 75 mg/L menimbulkan    hambatan     pertumbuhan    S. aureus lebih    tinggi dibandingkan dengan kelompok perlakuan I dengan konsentrasi 37,5 mg/L (p<0,05, uji lanjutan dengan uji beda nyata terkecil (BNT pada taraf  signifikansi  5% diperoleh  bahwa  hambatan  pertumbuhan S. aureus pada kelompok perlakuan II (75 mg/L berbeda bermakna dengan kelompok perlakuan I (37,5 mg/L (p<0,05. Bertolak dari pembahasan di atas dapat disimpulkan bahwa bioaktivitas forbazol E dapat menghambat pertumbuhan   S. aureus.

  16. Methicillin and vancomycin resistant S. aureus in hospitalized patients

    Directory of Open Access Journals (Sweden)

    Poonam Sood Loomba

    2010-01-01

    Full Text Available S. aureus is the major bacterial cause of skin, soft tissue and bone infections, and one of the commonest causes of healthcare-associated bacteremia. Hospital-associated methicillin-resistant S. aureus (MRSA carriage is associated with an increased risk of infection, morbidity and mortality. Screening of high-risk patients at the time of hospital admission and decolonization has proved to be an important factor in an effort to reduce nosocomial transmission. The electronic database Pub Med was searched for all the articles on "Establishment of MRSA and the emergence of vancomycin-resistant S. aureus (VRSA." The search included case reports, case series and reviews. All the articles were cross-referenced to search for any more available articles. A total of 88 references were obtained. The studies showed a steady increase in the number of vancomycin-intermediate and vancomycin-resistant S. aureus. Extensive use of vancomycin creates a selective pressure that favors the outgrowth of rare, vancomycin-resistant clones leading to heterogenous vancomycin intermediate S. aureus hVISA clones, and eventually, with continued exposure, to a uniform population of vancomycin-intermediate S. aureus (VISA clones. However, the criteria for identifying hVISA strains have not been standardized, complicating any determination of their clinical significance and role in treatment failures. The spread of MRSA from the hospital to the community, coupled with the emergence of VISA and VRSA, has become major concern among healthcare providers. Infection-control measures, reliable laboratory screening for resistance, appropriate antibiotic prescribing practices and avoidance of blanket treatment can prevent long-term emergence of resistance.

  17. Synthetic LPETG-containing peptide incorporation in the Staphylococcus aureus cell-wall in a sortase A- and growth phase-dependent manner.

    Directory of Open Access Journals (Sweden)

    Silvie Hansenová Maňásková

    Full Text Available The majority of Staphylococcus aureus virulence- and colonization-associated surface proteins contain a pentapeptide recognition motif (LPXTG. This motif can be recognized and cleaved by sortase A (SrtA which is a membrane-bound transpeptidase. After cleavage these proteins are covalently incorporated into the peptidoglycan. Therefore, SrtA plays a key role in S. aureus virulence. We aimed to generate a substrate mimicking this SrtA recognition motif for several purposes: to incorporate this substrate into the S. aureus cell-wall in a SrtA-dependent manner, to characterize this incorporation and to determine the effect of substrate incorporation on the incorporation of native SrtA-dependent cell-surface-associated proteins. We synthesized substrate containing the specific LPXTG motif, LPETG. As a negative control we used a scrambled version of this substrate, EGTLP and a S. aureus srtA knockout strain. Both substrates contained a fluorescence label for detection by FACScan and fluorescence microscope. A spreading assay and a competitive Luminex assay were used to determine the effect of substrate treatment on native LPXTG containing proteins deposition in the bacterial cell-wall. We demonstrate a SrtA-dependent covalent incorporation of the LPETG-containing substrate in wild type S. aureus strains and several other Gram-positive bacterial species. LPETG-containing substrate incorporation in S. aureus was growth phase-dependent and peaked at the stationary phase. This incorporation negatively correlated with srtA mRNA expression. Exogenous addition of the artificial substrate did not result in a decreased expression of native SrtA substrates (e.g. clumping factor A/B and protein A nor induced a srtA knockout phenotype.

  18. Study of Gentamicin Effect on Staphylococcus Aureus in the Presence of Electromagnetic Field

    Directory of Open Access Journals (Sweden)

    Asghar Tanomand

    2008-06-01

    Full Text Available Introduction:  Nowadays  the  medical,  therapeutic  and  pharmacological  application  of  magnetic  fields  (MF  and  its  biological  effect  has  raised  question  about  the  safety  of  MF.  This  study  aimed  at  scrutinizing the effect of static MF on the resistance of S. aureus to antibiotic.  Materials and Methods: This prospective, case–control study was conducted to evaluate the effect of  low intensity (0.5 mT static MF on the growth rate and the antibiotic resistance of S. aureus sensitive to  gentamicin. The studied bacterium is a nosocomial type and the growth rate was calculated by colony  counting to understand the effect of MF on it. In the next stage, the rate of bacterial growth along with  the different concentration of antibiotic was studied and the Minimum Inhibitory Concentration (MIC  and Minimum Bactericidal Concentration (MBC were determined.  Results: It is concluded that the 0.5 mT MF didn't affect the growth rate of S. aureus after 24 and 48 hours.  The 0.5 mT MF induced a 50 percent decline of MIC and MBC of gentamicin after a 48 hour incubation (MIC  = 4 6g /cc, MBC = 8 6g /cc in the case group vs. MIC = 8 6g /cc, MBC = 16 6g /cc in the control group.  Conclusion: Low–intensity MF didn't affect the bacterial growth rate. However, the bactericidal effects  of gentamicin were greater in the presence of MF. It is possible to apply the static MF for enhancing the  effect of antibiotic on S. aureus.

  19. Evaluation of metabolism of azo dyes and their effects on Staphylococcus aureus metabolome.

    Science.gov (United States)

    Sun, Jinchun; Jin, Jinshan; Beger, Richard D; Cerniglia, Carl E; Chen, Huizhong

    2017-10-01

    Dyes containing one or more azo linkages are widely applied in cosmetics, tattooing, food and drinks, pharmaceuticals, printing inks, plastics, leather, as well as paper industries. Previously we reported that bacteria living on human skin have the ability to reduce some azo dyes to aromatic amines, which raises potential safety concerns regarding human dermal exposure to azo dyes such as those in tattoo ink and cosmetic colorant formulations. To comprehensively investigate azo dye-induced toxicity by skin bacteria activation, it is very critical to understand the mechanism of metabolism of the azo dyes at the systems biology level. In this study, an LC/MS-based metabolomics approach was employed to globally investigate metabolism of azo dyes by Staphylococcus aureus as well as their effects on the metabolome of the bacterium. Growth of S. aureus in the presence of Sudan III or Orange II was not affected during the incubation period. Metabolomics results showed that Sudan III was metabolized to 4-(phenyldiazenyl) aniline (48%), 1-[(4-aminophenyl) diazenyl]-2-naphthol (4%) and eicosenoic acid Sudan III (0.9%). These findings indicated that the azo bond close to naphthalene group of Sudan III was preferentially cleaved compared with the other azo bond. The metabolite from Orange II was identified as 4-aminobenzene sulfonic acid (35%). A much higher amount of Orange II (~90×) was detected in the cell pellets from the active viable cells compared with those from boiled cells incubated with the same concentration of Orange II. This finding suggests that Orange II was primarily transported into the S. aureus cells for metabolism, instead of the theory that the azo dye metabolism occurs extracellularly. In addition, the metabolomics results showed that Sudan III affected energy pathways of the S. aureus cells, while Orange II had less noticeable effects on the cells. In summary, this study provided novel information regarding azo dye metabolism by the skin bacterium, the

  20. Brain infection following experimental Staphylococcus aureus sepsis in pigs

    DEFF Research Database (Denmark)

    Astrup, Lærke Boye; Iburg, Tine Moesgaard; Nielsen, Ole Lerberg

    2010-01-01

    Introduction: Sepsis is a major problem in humans and both the incidence and mortality is increasing. Multiple microabcesses can be found in the brain of septic patients. Staphylococcus aureus is one of the most common causes of sepsis and brain abscesses. S. aureus is also a frequent cause...... pigs were kept as controls. The pigs were euthanized in groups of four at either 6, 12, 24 or 48 h post infection. The brain was collected from all the animals and examined histologically. Results: All the inoculated pigs developed sepsis and 7 out of 12 animals had microabscesses in the prosencephalon...

  1. Staphylococcus aureus sternal osteomyelitis: a rare cause of chest pain

    Directory of Open Access Journals (Sweden)

    Kaur M

    2015-10-01

    Full Text Available Chest pain is a common presenting symptom with a broad differential. Life-threatening cardiac and pulmonary etiologies of chest pain should be evaluated first. However, it is critical to perform a thorough assessment for other sources of chest pain in order to limit morbidity and mortality from less common causes. We present a rare case of a previously healthy 45 year old man who presented with focal, substernal, reproducible chest pain and Staphylococcus aureus bacteremia who was later found to have primary Staphylococcus aureus sternal osteomyelitis.

  2. Beta-Hemolysin Promotes Skin Colonization by Staphylococcus aureus

    OpenAIRE

    Katayama, Yuki; Baba, Tadashi; Sekine, Miwa; Fukuda, Minoru; Hiramatsu, Keiichi

    2013-01-01

    Colonization by Staphylococcus aureus is a characteristic feature of several inflammatory skin diseases and is often followed by epidermal damage and invasive infection. In this study, we investigated the mechanism of skin colonization by a virulent community-acquired methicillin-resistant S. aureus (CA-MRSA) strain, MW2, using a murine ear colonization model. MW2 does not produce a hemolytic toxin, beta-hemolysin (Hlb), due to integration of a prophage, ϕSa3mw, inside the toxin gene (hlb). H...

  3. Staphylococcus aureus still colonizes the untreated neonatal umbilicus.

    Science.gov (United States)

    Watkinson, M; Dyas, A

    1992-06-01

    Two different neonatal umbilical cord treatment regimens were studied prospectively. Although a greater proportion of cords had separated by the seventh day in those babies not treated with topical antiseptics (47% vs. 26%), there was a significant excess (53% vs. 30%) of umbilical colonization by Staphylococcus aureus compared to those neonates whose cords were treated with alcohol wipes and hexachlorophane powder. The main purpose of treating cords is to prevent significant S. aureus colonization, and therefore current proposals to stop antiseptic treatment of umbilical cords should be disregarded.

  4. Response of Staphylococcus Aureus to a Spaceflight Analogue

    Science.gov (United States)

    Castro, S. L.; Ott, C. M.

    2010-01-01

    The decreased gravity of the spaceflight environment creates quiescent, low fluid shear conditions. This environment can impart considerable effects on the physiology of microorganisms as well as their interactions with potential hosts. Using the rotating wall vessel (RWV), as a spaceflight analogue, the consequence of low fluid shear culture on microbial pathogenesis has provided a better understanding of the risks to the astronaut crew from infectious microorganisms. While the outcome of low fluid shear culture has been investigated for several bacterial pathogens, little has been done to understand how this environmental factor affects Staphylococcus aureus. S. aureus is an opportunistic human pathogen which presents a high level of infection risk to the crew, as it has been isolated from both the space shuttle and International Space Station. Given that approximately forty percent of the population are carriers of the bacteria, eradication of this organism from in flight environments is impractical. These reasons have lead to us to assess the response of S. aureus to a reduced fluid shear environment. Culture in the RWV demonstrated that S. aureus grown under the low-shear condition had lower cell concentrations after 10 hours when compared to the control culture. Furthermore, the low-shear cultured bacteria displayed a reduction in carotenoid production, pigments responsible for their yellow/gold coloration. When exposed to various environmental stressors, post low-shear culture, a decrease in the ability to survive oxidative assault was observed compared to control cultures. The low fluid shear environment also resulted in a decrease in hemolysin secretion, a staphylococcal toxin responsible for red blood cell lysis. When challenged by the immune components present in human whole blood, low-shear cultured S. aureus demonstrated significantly reduced survival rates as compared to the control culture. Assays to determine the duration of these alterations

  5. Staphylococcus aureus CcpA affects biofilm formation

    OpenAIRE

    Seidl, K.; Goerke, C; Wolz, C; Mack, D; Berger-Bächi, B; Bischoff, M

    2008-01-01

    Biofilm formation in Staphylococcus aureus under in vitro growth conditions is generally promoted by high concentrations of sugar and/or salts. The addition of glucose to routinely used complex growth media triggered biofilm formation in S. aureus strain SA113. Deletion of ccpA, coding for the catabolite control protein A (CcpA), which regulates gene expression in response to the carbon source, abolished the capacity of SA113 to form a biofilm under static and flow conditions, while still all...

  6. Staphylococcus aureus and Lipopolysaccharide Modulate Gene Expressions of Drug Transporters in Mouse Mammary Epithelial Cells Correlation to Inflammatory Biomarkers.

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    Yagmur Yagdiran

    Full Text Available Inflammation in the mammary gland (mastitis is the most common disease in dairy herds worldwide, often caused by the pathogens Staphylococcus aureus (S. aureus and Escherichia coli (E. coli. Little is known about the effects of mastitis on drug transporters and the impact on transporter-mediated excretion of drugs into milk. We used murine mammary epithelial HC11 cells, after lactogenic differentiation into a secreting phenotype, and studied gene expressions of ABC- and SLC- transporters after treatment of cells with S. aureus and lipopolysaccharide, an endotoxin secreted by E. coli. The studied transporters were Bcrp, Mdr1, Mrp1, Oatp1a5, Octn1 and Oct1. In addition, Csn2, the gene encoding β-casein, was analyzed. As biomarkers of the inflammatory response, gene expressions of the cytokines Il6 and Tnfα and the chemokine Cxcl2 were determined. Our results show that S. aureus and LPS treatment of cells, at non-cytotoxic concentrations, induced an up-regulation of Mdr1 and of the inflammatory biomarkers, except that Tnfα was not affected by lipopolysaccharide. By simple regression analysis we could demonstrate statistically significant positive correlations between each of the transporters with each of the inflammatory biomarkers in cells treated with S. aureus. The coefficients of determination (R2 were 0.7-0.9 for all but one correlation. After treatment of cells with lipopolysaccharide, statistically significant correlations were only found between Mdr1 and the two parameters Cxcl2 and Il6. The expression of Csn2 was up-regulated in cells treated with S. aureus, indicating that the secretory function of the cells was not impaired. The strong correlation in gene expressions between transporters and inflammatory biomarkers may suggest a co-regulation and that the transporters have a role in the transport of cytokines and chemokines. Our results demonstrate that transporters in mammary cells can be affected by infection, which may have an

  7. Vancomycin intermediate-resistant Staphylococcus aureus (VISA) isolated from a patient who never received vancomycin treatment.

    Science.gov (United States)

    Zhu, Xuhui; Liu, Cailin; Gao, Sui; Lu, Yanfang; Chen, Zhongju; Sun, Ziyong

    2015-04-01

    With the abuse of antibiotics, the methicillin-resistant Staphylococcus aureus (MRSA) strain became prevalent. Furthermore, Staphylococcus aureus with a character of vancomycin intermediate-resistance (VISA) has been found globally since the first report in Japan. The main objectives of this study were to report a case of VISA isolated from a Chinese patient who had never undergone Vancomycin treatment, and to determine its molecular character. A total of 9 strains were recovered from a patient during the therapeutic process. Antimicrobial susceptibility testing was performed to determine their antibiotic susceptibility patterns. To detect the VISA strain's molecular epidemiological features, growth and morphological characters, we used multilocus sequence typing, autolysis assay and transmission electric microscope tests. Pulsed-field gel electrophoresis (PFGE) was performed to characterize the heterogeneities of all isolates. One isolate was found to exhibit vancomycin intermediated-resistant with MIC of 8 μg/ml. It was ST239-T030-agr-1, had thickened cell wall, and displayed a slower growth rate and reduced susceptibility to Triton X-100-induced autolysis than other strains. All 9 strains exhibited the same PFGE pattern. This is the first report of VISA found in central China from a patient who had never received vancomycin treatment. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Bactericidal Effect of a Photoresponsive Carbon Monoxide-Releasing Nonwoven against Staphylococcus aureus Biofilms

    Science.gov (United States)

    Klinger-Strobel, Mareike; Gläser, Steve; Makarewicz, Oliwia; Wyrwa, Ralf; Weisser, Jürgen

    2016-01-01

    Staphylococcus aureus is a leading pathogen in skin and skin structure infections, including surgical and traumatic infections that are associated with biofilm formation. Because biofilm formation is accompanied by high phenotypic resistance of the embedded bacteria, they are almost impossible to eradicate by conventional antibiotics. Therefore, alternative therapeutic strategies are of high interest. We generated nanostructured hybrid nonwovens via the electrospinning of a photoresponsive carbon monoxide (CO)-releasing molecule [CORM-1, Mn2(CO)10] and the polymer polylactide. This nonwoven showed a CO-induced antimicrobial activity that was sufficient to reduce the biofilm-embedded bacteria by 70% after photostimulation at 405 nm. The released CO increased the concentration of reactive oxygen species (ROS) in the biofilms, suggesting that in addition to inhibiting the electron transport chain, ROS might play a role in the antimicrobial activity of CORMs on S. aureus. The nonwoven showed increased cytotoxicity on eukaryotic cells after longer exposure, most probably due to the released lactic acid, that might be acceptable for local and short-time treatments. Therefore, CO-releasing nonwovens might be a promising local antimicrobial therapy against biofilm-associated skin wound infections. PMID:27114272

  9. SarT, a Repressor of α-Hemolysin in Staphylococcus aureus

    Science.gov (United States)

    Schmidt, Katherine A.; Manna, Adhar C.; Gill, Steven; Cheung, Ambrose L.

    2001-01-01

    In searching the Staphylococcus aureus genome, we found several homologs to SarA. One of these genes, sarT, codes for a basic protein with 118 residues and a predicted molecular size of 16,096 Da. Northern blot analysis revealed that the expression of sarT was repressed by sarA and agr. An insertion sarT mutant generated in S. aureus RN6390 and 8325-4 backgrounds revealed minimal effect on the expression of sarR and sarA. The RNAIII level was notably increased in the sarT mutant, particularly in postexponential-phase cells, while the augmentative effect on RNAII was less. SarT repressed the expression of α-hemolysin, as determined by Northern blotting, Western blotting, and a rabbit erythrocyte hemolytic assay. This repression was relieved upon complementation. Similar to agr and sarA mutants, which predictably displayed a reduction in hla expression, the agr sarT mutant exhibited a lower level of hla transcription than the sarT mutant. In contrast, hla transcription was enhanced in the sarA sarT mutant compared with the single sarA mutant. Collectively, these results indicated that the sarA locus, contrary to the regulatory action of agr, induced α-hemolysin production by repressing sarT, a repressor of hla transcription. PMID:11447147

  10. Interactions of methicillin resistant Staphylococcus aureus USA300 and Pseudomonas aeruginosa in polymicrobial wound infection.

    Directory of Open Access Journals (Sweden)

    Irena Pastar

    Full Text Available Understanding the pathology resulting from Staphylococcus aureus and Pseudomonas aeruginosa polymicrobial wound infections is of great importance due to their ubiquitous nature, increasing prevalence, growing resistance to antimicrobial agents, and ability to delay healing. Methicillin-resistant S. aureus USA300 is the leading cause of community-associated bacterial infections resulting in increased morbidity and mortality. We utilized a well-established porcine partial thickness wound healing model to study the synergistic effects of USA300 and P. aeruginosa on wound healing. Wound re-epithelialization was significantly delayed by mixed-species biofilms through suppression of keratinocyte growth factor 1. Pseudomonas showed an inhibitory effect on USA300 growth in vitro while both species co-existed in cutaneous wounds in vivo. Polymicrobial wound infection in the presence of P. aeruginosa resulted in induced expression of USA300 virulence factors Panton-Valentine leukocidin and α-hemolysin. These results provide evidence for the interaction of bacterial species within mixed-species biofilms in vivo and for the first time, the contribution of virulence factors to the severity of polymicrobial wound infections.

  11. Staphylococcus aureus hemolysin A disrupts cell-matrix adhesions in human airway epithelial cells.

    Science.gov (United States)

    Hermann, Ina; Räth, Susann; Ziesemer, Sabine; Volksdorf, Thomas; Dress, Regine J; Gutjahr, Melanie; Müller, Christian; Beule, Achim G; Hildebrandt, Jan-Peter

    2015-01-01

    Treatment of primary or immortalized human airway epithelial cells (16HBE14o-, S9) or alveolar cancer cells (A549) with recombinant hemolysin A (rHla), a major virulence-associated factor of Staphylococcus aureus, induces alterations in cell shape and formation of paracellular gaps in the cell layer. Semiquantitative Western blotting using extracts of freshly isolated airway tissue (nasal epithelium) or 16HBE14o- model cells revealed that phosphorylation levels of focal adhesion kinase (Fak) and paxillin were altered upon treatment of tissue or cells with rHla. Immune fluorescence analyses showed that rHla treatment of 16HBE14o- cells results in losses of vinculin and paxillin from focal contacts and a net reduction in the number of focal contacts. The actin cytoskeleton was strongly remodeled. We concluded that treatment of cells with rHla activates Fak signaling, which accelerates focal contact turnover and prevents newly formed focal contacts (focal complexes) from maturation to focal adhesions. The inability of rHla-treated cells to form stable focal adhesions may be one factor that contributes to gap formation in the cell layer. In vivo, such changes may disturb the defensive barrier function of the airway epithelium and may facilitate lung infections by S. aureus.

  12. Effects of Staphylococcus aureus-hemolysin A on calcium signalling in immortalized human airway epithelial cells.

    Science.gov (United States)

    Eichstaedt, Stefanie; Gäbler, Karoline; Below, Sabine; Müller, Christian; Kohler, Christian; Engelmann, Susanne; Hildebrandt, Petra; Völker, Uwe; Hecker, Michael; Hildebrandt, Jan-Peter

    2009-02-01

    Part of the innate defence of bronchial epithelia against bacterial colonization is secretion of salt and water which generally depends on coordinated actions of receptor-mediated cAMP- and calcium signalling. The hypothesis that Staphylococcus aureus-virulence factors interfere with endogenous signals in host cells was tested by measuring agonist-mediated changes in [Ca(2+)](i) in S9 cells upon pre-incubation with bacterial secretory products. S9 cells responded to mAChR-activation with calcium release from intracellular stores and capacitative calcium influx. Treatment of cells with culture supernatants of S. aureus (COL) or with recombinant alpha-hemolysin (Hla) resulted in time- and concentration-dependent changes in [Ca(2+)](i). High concentrations of Hla (2000 ng/ml) resulted in elevations in [Ca(2+)](i) elicited by accelerated calcium influx. A general Hla-mediated permeabilization of S9 cell membranes to small molecules, however, did not occur. Lower concentrations of Hla (200 ng/ml) induced a reduction in [Ca(2+)](i)-levels during the sustained plateau phase of receptor-mediated calcium signalling which was abolished by pre-incubation of cells with carboxyeosin, an inhibitor of the plasma membrane calcium-ATPase. This indicates that low concentrations of Hla change calcium signalling by accelerating pump-driven extrusion of Ca(2+) ions. In vivo, such a mechanism may result in attenuation of calcium-mediated cellular defence functions and facilitation of bacterial adherence to the bronchial epithelium.

  13. Bactericidal Effect of a Photoresponsive Carbon Monoxide-Releasing Nonwoven against Staphylococcus aureus Biofilms.

    Science.gov (United States)

    Klinger-Strobel, Mareike; Gläser, Steve; Makarewicz, Oliwia; Wyrwa, Ralf; Weisser, Jürgen; Pletz, Mathias W; Schiller, Alexander

    2016-07-01

    Staphylococcus aureus is a leading pathogen in skin and skin structure infections, including surgical and traumatic infections that are associated with biofilm formation. Because biofilm formation