Christof von Eiff

Publications of Christof von Eiff

• Catheter Colonization and Abscess Formation Due to Staphylococcus epidermidis with Normal and Small-Colony-Variant Phenotype Is Mouse Strain Dependent.

  Authors: Gunnar Sander, Tina Börner, André Kriegeskorte, Christof von Eiff, Karsten Becker, Esther Mahabir

  PloS one. 01/2012; 7(5):e36602.

  Coagulase-negative staphylococci (CoNS) form a thick, multilayered biofilm on foreign bodies and are a major cause of nosocomial implant-associated infections. Although foreign body infection modelsCoagulase-negative staphylococci (CoNS) form a thick, multilayered biofilm on foreign bodies and are a major cause of nosocomial implant-associated infections. Although foreign body infection models are well-established, limited in vivo data are available for CoNS with small-colony-variant (SCV) phenotype described as causative agents in implant-associated infections. Therefore, we investigated the impact of the Staphylococcus epidermidis phenotype on colonization of implanted PVC catheters and abscess formation in three different mouse strains. Following introduction of a catheter subcutaneously in each flank of 8- to 12-week-old inbred C57BL/6JCrl (B6J), outbred Crl:CD1(ICR) (CD-1), and inbred BALB/cAnNCrl (BALB/c) male mice, doses of S. epidermidis O-47 wild type, its hemB mutant with stable SCV phenotype, or its complemented mutant at concentrations of 10(6) to 10(9) colony forming units (CFUs) were gently spread onto each catheter. On day 7, mice were sacrificed and the size of the abscesses as well as bacterial colonization was determined. A total of 11,500 CFUs of the complemented mutant adhered to the catheter in BALB/c followed by 9,960 CFUs and 9,900 CFUs from S. epidermidis wild type in BALB/c and CD-1, respectively. SCV colonization was highest in CD-1 with 9,500 CFUs, whereas SCVs were not detected in B6J. The minimum dose that led to colonization or abscess formation in all mouse strains was 10(7) or 10(8) CFUs of the normal phenotype, respectively. A minimum dose of 10(8) or 10(9) CFU of the hemB mutant with stable SCV phenotype led to colonization only or abscess formation, respectively. The largest abscesses were detected in BALB/c inoculated with wild type bacteria or SCV (64 mm(2) vs. 28 mm(2)). Our results indicate that colonization and abscess formation by different phenotypes of S. epidermidis in a foreign body infection model is most effective in inbred BALB/c followed by outbred CD-1 and inbred B6J mice.

• In vitro activity against Staphylococcus aureus of a novel antimicrobial agent, PRF-119, a recombinant chimeric bacteriophage endolysin.

  Authors: Evgeny A Idelevich, Christof von Eiff, Alexander W Friedrich, Domenico Iannelli, Guoqing Xia, Georg Peters, Andreas Peschel, Ingrid Wanninger, Karsten Becker

  Antimicrobial agents and chemotherapy. 09/2011; 55(9):4416-9.

  Antistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolatesAntistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolates were 0.098 μg/ml and 0.391 μg/ml, respectively (range, 0.024 to 0.780 μg/ml). Both the MIC(50) and MIC(90) values of 776 methicillin-resistant S. aureus isolates were 0.391 μg/ml (range, 0.024 to 1.563 μg/ml). All 192 clinical isolates of coagulase-negative staphylococci exhibited MIC values of >50 μg/ml. In conclusion, PRF-119 exhibited very good activity specifically against S. aureus.

• Functional assessment of a promoter polymorphism in S100B, a putative risk variant for bipolar disorder.

  Authors: Elif Dagdan, Derek W Morris, Matthew Campbell, Matthew Hill, Matthias Rothermundt, Florian Kästner, Christa Hohoff, Christof von Eiff, Petra Krakowitzky, Michael Gill, Patrick McKeon, Siobhan Roche

  American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. 06/2011; 156B(6):691-9.

  Calcium-binding protein S100B has been implicated in the pathology of bipolar affective disorder (BPAD) and schizophrenia (SZ). S100B protein levels are elevated in serum of patients with bothCalcium-binding protein S100B has been implicated in the pathology of bipolar affective disorder (BPAD) and schizophrenia (SZ). S100B protein levels are elevated in serum of patients with both disorders compared to controls. We previously reported genetic association of a SNP in the promoter of S100B, rs3788266, with a psychotic form of BPAD. To test for genotypic effects of rs3788266 in vivo, S100B serum protein levels were measured in 350 Irish and German subjects of known S100B genotype. The functional effect of rs3788266 on S100B promoter activity was studied using the luciferase reporter system in U373MG glioblastoma and SH-SY5Y neuroblastoma cell lines. Allelic effects of rs3788266 on protein complex formation at the S100B promoter were investigated by an electrophoretic mobility shift assay. Higher mean serum S100B levels were associated with the risk G allele of rs3788266 in BPAD cases (P = 0.0001), unaffected relatives of BPAD cases (P < 0.0001) and unrelated controls (P < 0.0001). Consistent with the in vivo findings, luciferase gene expression was significantly increased in the presence of the G allele compared to the A allele in SH-SY5Y (P = <0.0001), and in U373MG (P = <0.0008) cell lines. The binding affinity of both SH-SY5Y and U373MG protein complexes for the S100B promoter was significantly stronger in the presence of G allele compared to the A allele promoter fragments. These data support rs3788266 as a functional promoter variant in the S100B gene where the presence of the G allele promotes increased gene expression and is associated with increased serum levels of the protein.

• Small colony variants of Staphylococcus aureus reveal distinct protein profiles.

  Authors: André Kriegeskorte, Simone König, Gunnar Sander, Alexander Pirkl, Esther Mahabir, Richard A Proctor, Christof von Eiff, Georg Peters, Karsten Becker

  Proteomics. 06/2011; 11(12):2476-90.

  Small-colony variants (SCVs) of Staphylococcus aureus represent a slow-growing subpopulation causing chronic and relapsing infections due to their physiological adaptation on an intracellularSmall-colony variants (SCVs) of Staphylococcus aureus represent a slow-growing subpopulation causing chronic and relapsing infections due to their physiological adaptation on an intracellular lifestyle. In this first proteomic study on physiological changes associated with a natural, clinically derived SCV, its proteomic profile was investigated in comparison to corresponding isogenic strains displaying normal (clinical wild-type strain, complemented hemB mutant and spontaneous revertant of the clinical SCV) and SCV phenotypes (hemB mutant and gentamicin-induced SCV). Applying an ultra-high resolution chromatography and high mass accuracy MS(E) -based label-free relative and absolute protein quantification approach, the whole cytoplasmic proteome of this strain sextet was investigated in a growth phase-controlled manner covering early-exponential, late-exponential and stationary phases. Of 1019 cytoplasmic proteins identified, 154 were found to be differently regulated between strains. All SCV phenotypes showed down-regulation of the tricarboxylic acid (TCA) cycle-related proteins and of a protein cluster involved in purine/pyrimidine and folate metabolism. In contrast to hemB mutant and gentamicin-induced SCVs, the clinically derived SCVs showed no prominent up-regulation of glycolytic proteins. The spontaneous switch into the normal phenotype resulted in up-regulation of TCA cycle-related parts, while oxidative stress-related proteins were down-regulated. However, the natural revertant from the clinical SCV retained also dominant protein features of the clinical SCV phenotype. In conclusion, physiological changes between normal and SCV S. aureus phenotypes are more complex than reflected by defined electron transport chain-interrupting mutants and their complemented counterparts.

• Genomic and proteomic characterization of Staphylococcus aureus mastitis isolates of bovine origin.

  Authors: Carmen Wolf, Harald Kusch, Stefan Monecke, Dirk Albrecht, Silva Holtfreter, Christof von Eiff, Wolfram Petzl, Pascal Rainard, Barbara M Bröker, Susanne Engelmann

  Proteomics. 06/2011; 11(12):2491-502.

  Staphylococcus aureus colonizes and infects humans as well as animals. In the present study, 17 S. aureus strains isolated from cows suffering from mastitis were characterized. The well-establishedStaphylococcus aureus colonizes and infects humans as well as animals. In the present study, 17 S. aureus strains isolated from cows suffering from mastitis were characterized. The well-established multilocus sequence typing (MLST) technique and a diagnostic microarray covering 185 S. aureus virulence and resistance genes were used for genetic and epidemiological analyses. Virulence gene expression studies were performed by analyzing the extracellular protein pattern of each isolate on 2-D gels. By this way, a pronounced heterogeneity of the extracellular proteome between the bovine isolates has been observed which was attributed to genome plasticity and variation of gene expression. Merely 12 proteins were expressed in at least 80% of the isolates, i.e. Atl, Aur, GlpQ, Hla, LtaS, Nuc, PdhB, SAB0846, SAB2176, SAB0566, SspA, and SspB forming the core exoproteome. Fifteen extracellular proteins were highly variably expressed and only present in less than 20% of the isolates. This includes the serine proteases SplB, C, and F, and the superantigens SEC-bov, SEL and TSST-1. Compared to human isolates we identified at least six proteins with significantly different expression frequencies. While SAB0846 was expressed more frequently in bovine isolates, LytM, EbpS, Spa, Geh, and LukL1 were seen less frequently in these isolates.

• Intra- and extracellular activities of dicloxacillin and linezolid against a clinical Staphylococcus aureus strain with a small-colony-variant phenotype in an in vitro model of THP-1 macrophages and an in vivo mouse peritonitis model.

  Authors: Anne Sandberg, Sandrine Lemaire, Françoise Van Bambeke, Paul M Tulkens, Diarmaid Hughes, Christof von Eiff, Niels Frimodt-Møller

  Antimicrobial agents and chemotherapy. 01/2011; 55(4):1443-52.

  The small-colony-variant (SCV) phenotype of Staphylococcus aureus has been associated with difficult-to-treat infections, reduced antimicrobial susceptibility, and intracellular persistence. ThisThe small-colony-variant (SCV) phenotype of Staphylococcus aureus has been associated with difficult-to-treat infections, reduced antimicrobial susceptibility, and intracellular persistence. This study represents a detailed intra- and extracellular investigation of a clinical wild-type (WT) S. aureus strain and its counterpart with an SCV phenotype both in vitro and in vivo, using the THP-1 cell line model and the mouse peritonitis model, respectively. Bacteria of both phenotypes infected the mouse peritoneum intra- and extracellularly. The SCV phenotype was less virulent and showed distinct bacterial clearance, a reduced multiplication capacity, and a reduced internalization ability. However, some of the SCV-infected mice were still culture positive up to 96 h postinfection, and bacteria of this phenotype could spread to the mouse kidney and furthermore revert to the more virulent WT phenotype in both the mouse peritoneum and kidney. The SCV phenotype is therefore, despite reduced virulence, an important player in S. aureus pathogenesis. In the THP-1 cell line model, both dicloxacillin (DCX) and linezolid (LZD) reduced the intracellular inocula of bacteria of both phenotypes by approximately 1 to 1.5 log(10) in vitro, while DCX was considerably more effective against extracellular bacteria. In the mouse peritonitis model, DCX and LZD were also able to control both intra- and extracellular infections caused by either phenotype. Treatment with a single dose of DCX and LZD was, however, insufficient to clear the SCVs in the kidneys, and the risk of recurrent infection remained. This stresses the importance of an optimal dosing of the antibiotic when SCVs are present.

• The matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)-based protein peaks of 4448 and 5302 Da are not associated with the presence of Panton-Valentine leukocidin.

  Authors: Florian Szabados, Karsten Becker, Christof von Eiff, Martin Kaase, Sören Gatermann

  International journal of medical microbiology : IJMM. 01/2011; 301(1):58-63.

  The Panton-Valentine leukocidin (PVL) of Staphylococcus aureus plays an important role in the pathogenesis of necrotizing pneumonia and recurrent skin and soft tissue infections. The gene encodingThe Panton-Valentine leukocidin (PVL) of Staphylococcus aureus plays an important role in the pathogenesis of necrotizing pneumonia and recurrent skin and soft tissue infections. The gene encoding for PVL, lukS/F-PV, is distributed by prophages and can thus spread between isolates. Molecular methods have normally been used to identify lukS/F-PV-positive strains. Recently, however, a matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)-based method has been described to identify PVL-positive S. aureus strains. The aim of this study was thus to investigate the association of distinct MALDI-TOF MS peaks to the toxin profile in molecularly characterized methicillin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) strains harbouring lukS/F-PV. In contrast to the previous results, the MALDI-TOF MS peaks were detected in all 104 recently described molecularly divergent MRSA irrespective of the presence of PVL. Our result indicates that these described peaks seem to be independent of the presence of PVL.

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• Population structure of Staphylococcus aureus from remote African Babongo Pygmies.

  Authors: Frieder Schaumburg, Robin Köck, Alexander W Friedrich, Solange Soulanoudjingar, Ulysse Ateba Ngoa, Christof von Eiff, Saadou Issifou, Peter G Kremsner, Mathias Herrmann, Georg Peters, Karsten Becker

  PLoS neglected tropical diseases. 01/2011; 5(5):e1150.

  Pandemic community-acquired methicillin-resistant Staphylococcus aureus isolates (CA-MRSA) predominantly encode the Panton-Valentine leukocidin (PVL), which can be associated with severe infections.Pandemic community-acquired methicillin-resistant Staphylococcus aureus isolates (CA-MRSA) predominantly encode the Panton-Valentine leukocidin (PVL), which can be associated with severe infections. Reports from non-indigenous Sub-Saharan African populations revealed a high prevalence of PVL-positive isolates. The objective of our study was to investigate the S. aureus carriage among a remote indigenous African population and to determine the molecular characteristics of the isolates, particularly those that were PVL-positive. Nasal S. aureus carriage and risk factors of colonization were systematically assessed in remote Gabonese Babongo Pygmies. Susceptibility to antibiotics, possession of toxin-encoding genes (i.e., PVL, enterotoxins, and exfoliative toxins), S. aureus protein A (spa) types and multi-locus sequence types (MLST) were determined for each isolate. The carriage rate was 33%. No MRSA was detected, 61.8% of the isolates were susceptible to penicillin. Genes encoding PVL (55.9%), enterotoxin B (20.6%), exfoliative toxin D (11.7%) and the epidermal cell differentiation inhibitor B (11.7%) were highly prevalent. Thirteen spa types were detected and were associated with 10 STs predominated by ST15, ST30, ST72, ST80, and ST88. The high prevalence of PVL-positive isolates among Babongo Pygmies demands our attention as PVL can be associated with necrotinzing infection and may increase the risk of severe infections in remote Pygmy populations. Many S. aureus isolates from Babongo Pygmies and pandemic CA-MRSA-clones have a common genetic background. Surveillance is needed to control the development of resistance to antibiotic drugs and to assess the impact of the high prevalence of PVL in indigenous populations.

• Staphylococcus aureus small-colony variants are adapted phenotypes for intracellular persistence.

  Authors: Lorena Tuchscherr, Vanessa Heitmann, Muzaffar Hussain, Dorothee Viemann, Johannes Roth, Christof von Eiff, Georg Peters, Karsten Becker, Bettina Löffler

  The Journal of infectious diseases. 10/2010; 202(7):1031-40.

  Staphylococcus aureus is an important human pathogen of endovascular diseases, which can take a chronic course with a high relapse rate despite antimicrobial treatment. Thus far, persistent andStaphylococcus aureus is an important human pathogen of endovascular diseases, which can take a chronic course with a high relapse rate despite antimicrobial treatment. Thus far, persistent and antibiotic-refractory infections have been largely associated with a subpopulation of S. aureus, the small-colony variants (SCVs). In this work, we used endothelial cells to investigate infection with the highly virulent wild-type isolate (6850), 2 stable isogenic SCV phenotypes (hemB mutant IIb13 and JB1), and the complemented mutant. All strains were highly invasive in endothelial cells but largely differed in host response induction. Microarray analysis showed that wild-type phenotypes up-regulated a large number of endothelial genes (including genes involved in innate immunity), whereas the SCVs did not cause these dramatic changes. The inflammatory response and cytotoxicity were strongest shortly after infection and largely decreased within the following days, which was accompanied by a fast elimination of intracellular wild-type bacteria. By contrast, SCVs survived within endothelial cells at high numbers. S. aureus intracellular persistence via the development of an adapted subpopulation of SCVs most likely represents an important strategy of S. aureus to hide within the host cells, which could be a reservoir for chronic infections.

• Candida albicans and its metabolite gliotoxin inhibit platelet function via interaction with thiols.

  Authors: Anne Bertling, Silke Niemann, Andreas Uekötter, Wolfgang Fegeler, Cornelia Lass-Flörl, Christof von Eiff, Beate E Kehrel

  Thrombosis and haemostasis. 08/2010; 104(2):270-8.

  Platelets bind to Candida albicans, the major cause of candidiasis. But in contrast to other microorganisms the fungus does not aggregate platelets. Gliotoxin (GT), which possesses immunosuppressivePlatelets bind to Candida albicans, the major cause of candidiasis. But in contrast to other microorganisms the fungus does not aggregate platelets. Gliotoxin (GT), which possesses immunosuppressive properties, is produced by various fungi, including the opportunistic pathogens Aspergillus fumigatus and C. albicans . Its mode of action involves the formation of mixed disulfides with host proteins. Disulfide exchanges play an important role in platelet activation. Therefore, the effect of C. albicans and GT on platelet function was tested. C. albicans yeast cells (5,000-10,000 cells/microl) and GT, in pathophysiologically relevant concentrations (0.05-0.5 microM), inhibited platelet fibrinogen binding, anti gp IIb/IIIa antibody PAC-1 binding, aggregation and procoagulant activity in a dose-dependent manner. Alpha granule release, measured via CD62P surface expression, was not affected. Addition of reduced glutathione partially counteracted the effect of C. albicans and GT on platelet fibrinogen binding and platelet aggregation. The C. albicans metabolite GT features antithrombotic properties in addition to its immunosuppressive functions. Since treatment with reduced glutathione partially counteracted the inhibitory effect of C. albicans yeast cells and GT on platelet fibrinogen binding, the antithrombotic activity is likely to depend on the disulfide bridge of this mycotoxin. GT production by C. albicans could contribute to its survival in the blood stream during vascular infections. The knowledge of the underlying mechanisms of the antithrombotic properties might help to treat fungal infections as well as thrombosis.

• Reduction of periprosthetic infection with silver-coated megaprostheses in patients with bone sarcoma.

  Authors: Jendrik Hardes, Christof von Eiff, Arne Streitbuerger, Maurice Balke, Tymoteus Budny, Marcel P Henrichs, Gregor Hauschild, Helmut Ahrens

  Journal of surgical oncology. 04/2010; 101(5):389-95.

  The placement of megaprostheses in patients with bone sarcoma is associated with high rates of infection, despite prophylactic antibiotic administration. In individual cases, secondary amputation isThe placement of megaprostheses in patients with bone sarcoma is associated with high rates of infection, despite prophylactic antibiotic administration. In individual cases, secondary amputation is unavoidable in the effort to cure infection. The infection rate in 51 patients with sarcoma (proximal femur, n = 22; proximal tibia, n = 29) who underwent placement of a silver-coated megaprosthesis was assessed prospectively over a 5-year period, along with the treatment administered for infection. The infection rate was compared with the data for 74 patients in whom an uncoated titanium megaprosthesis (proximal femur, n = 33; proximal tibia, n = 41) was implanted. The infection rate was substantially reduced from 17.6% in the titanium to 5.9% in the silver group. Whereas 38.5% of patients in the titanium group ultimately had to undergo amputation when periprosthetic infection developed, these mutilating surgical procedures were not necessary in the study group. The use of silver-coated prostheses reduced the infection rate in the medium term. In addition, less aggressive treatment of infection was possible in the group with silver-coated prostheses. Further studies with longer term follow-up periods and larger numbers of patients are warranted in order to confirm these encouraging results.

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

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

  Molecular microbiology. 03/2010; 76(5):1142-61.

  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.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.

• Identification of differentially expressed small non-protein-coding RNAs in Staphylococcus aureus displaying both the normal and the small-colony variant phenotype.

  Authors: Luay F Abu-Qatouseh, Suresh V Chinni, Jochen Seggewiss, Richard A Proctor, Jürgen Brosius, Timofey S Rozhdestvensky, Georg Peters, Christof von Eiff, Karsten Becker

  Journal of molecular medicine (Berlin, Germany). 02/2010; 88(6):565-75.

  The emerging interest in RNA research is due to the discovery that bacterial non-protein-coding RNAs (npcRNAs; often referred to as "non-coding RNAs") are central regulatory molecules. While singleThe emerging interest in RNA research is due to the discovery that bacterial non-protein-coding RNAs (npcRNAs; often referred to as "non-coding RNAs") are central regulatory molecules. While single npcRNAs have been described in Staphylococcus aureus, mostly based on computational-based approaches, experimental data on npcRNAs and their impact on the formation of different phenotypes of S. aureus are missing. Consequently, two specialized cDNA libraries were constructed from total RNA collected from different growth phases of an isogenic clinical strain pair of S. aureus displaying both the normal and the small-colony variant phenotype. Overall, 142 candidates for novel npcRNAs were identified and their expression analyzed by Northern blot assays. Of these, the presence of 18 novel npcRNAs in S. aureus was experimentally confirmed. In fact, growth phase-specific regulation was detected for almost all of the novel npcRNAs, with different npcRNA expression patterns detectable for both phenotypes. Of particular interest, S. aureus phenotype-specific expression of four novel npcRNAs was documented. Thus, the presence of differentially expressed npcRNAs in S. aureus may help to understand the phenotypic variation and its associated pathogenicity.

• A poke into the diversity and associations within human anterior nare microbial communities.

  Authors: Melissa L Wos-Oxley, Iris Plumeier, Christof von Eiff, Stefan Taudien, Matthias Platzer, Ramiro Vilchez-Vargas, Karsten Becker, Dietmar H Pieper

  The ISME journal. 02/2010; 4(7):839-51.

  The anterior nares are the major reservoir for Staphylococcus aureus in humans, where nasal carriage has a crucial function as a source for invasive infections. Despite various investigations onThe anterior nares are the major reservoir for Staphylococcus aureus in humans, where nasal carriage has a crucial function as a source for invasive infections. Despite various investigations on aerobic community members based on traditional cultivation methods, little is known on the overall microbial composition and complex in situ interactions, but such knowledge is highly warranted for effective S. aureus control strategies. As assessed using advanced culture-independent approaches, this study provides a comprehensive survey of the anterior nare bacterial community of 40 individuals. Previously undiscovered co-colonization patterns and natural variations in species composition were revealed and provide insights for future intervention strategies for the control of health-care- and community-associated S. aureus infections.

• Activation of hypoxia inducible factor 1 is a general phenomenon in infections with human pathogens.

  Authors: Nadine Werth, Christiane Beerlage, Christian Rosenberger, Amir S Yazdi, Markus Edelmann, Amro Amr, Wanja Bernhardt, Christof von Eiff, Karsten Becker, Andrea Schäfer, Andreas Peschel, Volkhard A J Kempf

  PloS one. 01/2010; 5(7):e11576.

  Hypoxia inducible factor (HIF)-1 is the key transcriptional factor involved in the adaptation process of cells and organisms to hypoxia. Recent findings suggest that HIF-1 plays also a crucial roleHypoxia inducible factor (HIF)-1 is the key transcriptional factor involved in the adaptation process of cells and organisms to hypoxia. Recent findings suggest that HIF-1 plays also a crucial role in inflammatory and infectious diseases. Using patient skin biopsies, cell culture and murine infection models, HIF-1 activation was determined by immunohistochemistry, immunoblotting and reporter gene assays and was linked to cellular oxygen consumption. The course of a S. aureus peritonitis was determined upon pharmacological HIF-1 inhibition. Activation of HIF-1 was detectable (i) in all ex vivo in biopsies of patients suffering from skin infections, (ii) in vitro using cell culture infection models and (iii) in vivo using murine intravenous and peritoneal S. aureus infection models. HIF-1 activation by human pathogens was induced by oxygen-dependent mechanisms. Small colony variants (SCVs) of S. aureus known to cause chronic infections did not result in cellular hypoxia nor in HIF-1 activation. Pharmaceutical inhibition of HIF-1 activation resulted in increased survival rates of mice suffering from a S. aureus peritonitis. Activation of HIF-1 is a general phenomenon in infections with human pathogenic bacteria, viruses, fungi and protozoa. HIF-1-regulated pathways might be an attractive target to modulate the course of life-threatening infections.

• Immunomodulation of Nasal Epithelial Cells by Staphylococcus aureus-Derived Serine Proteases.

  Authors: Claudia Rudack, Florian Sachse, Nils Albert, Karsten Becker, Christof von Eiff

  Journal of immunology (Baltimore, Md. : 1950). 11/2009;

  The impact of Staphylococcus aureus in the pathogenesis of chronic rhinosinusitis is not well understood. Therefore, we investigated primary human nasal epithelial cell cultures for their ability toThe impact of Staphylococcus aureus in the pathogenesis of chronic rhinosinusitis is not well understood. Therefore, we investigated primary human nasal epithelial cell cultures for their ability to produce IL-8, growth-related oncogene-alpha, and IL-6 via stimulation with trypsin and culture supernatants of different S. aureus strains and phenotypes. Inhibition of cytokine synthesis was performed using a glucocorticoid, a serine protease inhibitor, and a cysteine protease inhibitor. Finally, signal transduction pathways were analyzed by quantifying phosphorylated forms of MAPKs (PI3K, ERK, and p38) and DNA-binding assays that quantified NF-kappaB and its inhibition using BAY11-7085. In vitro studies showed that the induction of IL-8, growth-related oncogene-alpha, and IL-6 by S. aureus culture supernatants was significantly inhibited by the serine protease inhibitor. In contrast, steroids and the cysteine protease inhibitor had little effect. Activation of NF-kappaB was observed after cell treatment with trypsin and bacterial supernatants, and was inhibited by BAY11-7085 and the serine protease inhibitor. S. aureus serine proteases were identified to modulate chemokine synthesis and activate NF-kappaB in nasal epithelial cells, and may therefore be relevant for the pathophysiology of chronic rhinosinusitis.

• Vancomycin and Daptomycin Pharmacodynamics Differ Against a Site-Directed Staphylococcus epidermidis Mutant Displaying the Small Colony Variant Phenotype.

  Authors: Marina Wu, Christof von Eiff, Nahed Al Laham, Brian T Tsuji

  Antimicrobial agents and chemotherapy. 07/2009;

  Catheter-related bloodstream infections due to slow-growing Staphylococcus epidermidis small colony variants (SCVs) are extremely difficult-to-treat. Daptomycin and vancomycin pharmacodynamics wereCatheter-related bloodstream infections due to slow-growing Staphylococcus epidermidis small colony variants (SCVs) are extremely difficult-to-treat. Daptomycin and vancomycin pharmacodynamics were evaluated against a site directed hemB mutant of S. epidermidis displaying the SCV phenotype and compared to the parental strain. Maximal effect decreased by 7.7-fold for vancomycin and 1.5-fold for daptomycin against the SCV mutant which was well characterized by a hill type mathematical model (R(2) >0.97).

• Daptomycin pharmacodynamics against Staphylococcus aureus hemB mutants displaying the small colony variant phenotype.

  Authors: Damir Begic, Christof von Eiff, Brian T Tsuji

  The Journal of antimicrobial chemotherapy. 06/2009; 63(5):977-81.

  OBJECTIVES: Staphylococcus aureus small colony variants (SCVs) are slow-growing morphological variants associated with persistent infections. While vancomycin activity has been shown to be attenuatedOBJECTIVES: Staphylococcus aureus small colony variants (SCVs) are slow-growing morphological variants associated with persistent infections. While vancomycin activity has been shown to be attenuated against SCVs of S. aureus, few data exist regarding daptomycin. The objective was to evaluate the pharmacodynamics of daptomycin against defined S. aureus mutants displaying the SCV phenotype. METHODS: Two S. aureus hemB mutants (Ia48 and III33) displaying the SCV phenotype and their parental strains (COL and Newman) were evaluated. Time-kill experiments were performed using a starting inoculum of 10(6) cfu/mL at 0, 0.25, 0.5, 1, 2, 4, 8, 16, 32 and 64 times the MIC. Samples were obtained at 0, 1, 2, 4, 6, 8 and 24 h, plated and incubated to determine colony counts. A Hill-type pharmacodynamic mathematical model was fitted to the data to characterize the effect. RESULTS: Bactericidal activity for daptomycin was achieved and occurred in a concentration-dependent manner against both hemB mutants and their parental strains. Against strains with normal phenotype, bactericidal activity was achieved rapidly, within 2 h at concentrations > or =16 times the MIC, while against SCVs, bactericidal activity was achieved within 6 h at concentrations > or =16 times the MIC. Against both hemB mutants, daptomycin maintained bactericidal activity at 24 h, with similar profiles of killing activity when compared with their parental strains. CONCLUSIONS: Daptomycin achieved bactericidal activity against S. aureus hemB mutants and parenteral isolates. Daptomycin represents a potential therapeutic option for infections caused by S. aureus strains displaying the SCV phenotype and additional studies are warranted.

• Capsule Expression and Genotypic Differences Among Staphylococcus aureus Isolates from Patients with Chronic or Acute Osteomyelitis.

  Authors: Santiago M Lattar, Lorena P N Tuchscherr, Roberto L Caccuri, Daniela Centrón, Karsten Becker, Claudio A Alonso, Claudia Barberis, Graciela Miranda, Fernanda R Buzzola, Christof von Eiff, Daniel O Sordelli

  Infection and immunity. 04/2009;

  There is ample evidence that S. aureus capsule polysaccharide (CP) promotes virulence. Loss of capsule expression, however, may lead to S. aureus persistence in the chronically infected host. ThisThere is ample evidence that S. aureus capsule polysaccharide (CP) promotes virulence. Loss of capsule expression, however, may lead to S. aureus persistence in the chronically infected host. This study was conducted to determine the relative prevalence of non-encapsulated S. aureus in patients with chronic and acute osteomyelitis. Only 76/118 (64%) S. aureus isolates from patients with osteomyelitis expressed CP whereas all 50 isolates from blood cultures of patients with infections other than osteoarticular expressed CP (P=0.0001). A significantly higher prevalence of non-encapsulated S. aureus was found in patients with chronic (53%) compared with those with acute osteomyelitis (21%) (P=0.0046). S. aureus isolates obtained from multiple specimens from five of six patients with chronic osteomyelitis exhibited phenotypic [expression of CP, alpha-hemolysin, beta-hemolysin, slime and small-colony variant (SCV) phenotype] and/or genotypic (PFGE and spa typing) differences. Non-encapsulated S. aureus was recovered from at least one specimen from each chronic patient. Fourteen isolates obtained from two patients with acute osteomyelitis were indistinguishable from each other within each group and all produced CP5. In conclusion, we demonstrated that non-encapsulated S. aureus are more frequently isolated from patients with chronic osteomyelitis, compared with those with acute osteomyelitis, suggesting that loss of CP expression may be advantageous to S. aureus during chronic infection. Our findings in multiple S. aureus isolates from individual patients allowed us to suggest that selection of non-encapsulated S. aureus may have likely occurred in the patient during long term bone infection.

• Risk variants in the S100B gene predict elevated S100B serum concentrations in healthy individuals.

  Authors: Christa Hohoff, Gerald Ponath, Christine M Freitag, Florian Kästner, Petra Krakowitzky, Katharina Domschke, Katja Koelkebeck, Frank Kipp, Christof von Eiff, Jürgen Deckert, Matthias Rothermundt

  American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. 04/2009;

  Several lines of evidence suggest an important role of the S100B protein and its coding gene in different neuropathological and psychiatric disorders like dementia, bipolar affective disorders andSeveral lines of evidence suggest an important role of the S100B protein and its coding gene in different neuropathological and psychiatric disorders like dementia, bipolar affective disorders and schizophrenia. To clarify whether a direct link exists between gene and gene product, that is, whether S100B variants directly modulate S100B serum concentration, 196 healthy individuals were assessed for S100B serum concentrations and genotyped for five potentially functional S100B SNPs. Functional variants of the serotonergic genes 5-HT1A and 5-HTT possibly modulating S100B serum levels were also studied. Further, publicly available human postmortem gene expression data were re-analyzed to elucidate the impact of S100B, 5-HT1A and 5-HTT SNPs on frontal cortex S100B mRNA expression. Several S100B SNPs, particularly rs9722, and the S100B haplotype T-G-G-A (including rs2186358-rs11542311-rs2300403-rs9722) were associated with elevated S100B serum concentrations (Bonferroni corrected P < 0.05). Of these, rs11542311 was also associated with S100B mRNA expression directly (Bonferroni corrected P = 0.05) and within haplotype G-A-T-C (rs11542311-rs2839356-rs9984765-rs881827; P = 0.004), again with the G-allele increasing S100B expression. Our results suggest an important role of S100B SNPs on S100B serum concentrations and S100B mRNA expression. It hereby links recent evidence for both, the impact of S100B gene variation on various neurological or psychiatric disorders like dementia, bipolar affective disorders and schizophrenia and the strong relation between S100B serum levels and these disorders. (c) 2009 Wiley-Liss, Inc.