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Biofilm-related infections occur quite frequently in hospital settings and require rapid diagnostic identification as they are recalcitrant to antibiotic therapy and make special treatment necessary. One of the standard microbiological in vitro tests is the crystal violet test. It indirectly determines the amount of biofilm by measuring the optical density (OD) of the crystal violet-stained biofilm matrix and cells. However, this test is quite time-consuming, as it requires bacterial cultivation up to several days. In this study, we correlate fast Raman spectroscopic read-out of clinical Staphylococcus aureus isolates from 47 patients with different disease background with their biofilm-forming characteristics. Included were low (OD < 10), medium (OD ≥ 10 and ≤20), and high (OD > 20) biofilm performers as determined by the crystal violet test. Raman spectroscopic analysis of the bacteria revealed most spectral differences between high and low biofilm performers in the fingerprint region between 750 and 1150 cm−1. Using partial least square regression (PLSR) analysis on the Raman spectra involving the three categories of biofilm formation, it was possible to obtain a slight linear correlation of the Raman spectra with the biofilm OD values. The PLSR loading coefficient highlighted spectral differences between high and low biofilm performers for Raman bands that represent nucleic acids, carbohydrates, and proteins. Our results point to a possible application of Raman spectroscopy as a fast prediction tool for biofilm formation of bacterial strains directly after isolation from the infected patient. This could help clinicians make timely and adapted therapeutic decision in future.
Christina Ebert; Lorena Tuchscherr; Nancy Unger; Christine Pöllath; Frederike Gladigau; Jürgen Popp; Bettina Löffler; Ute Neugebauer. Correlation of crystal violet biofilm test results of Staphylococcus aureus clinical isolates with Raman spectroscopic read‐out. Journal of Raman Spectroscopy 2021, 1 .
AMA StyleChristina Ebert, Lorena Tuchscherr, Nancy Unger, Christine Pöllath, Frederike Gladigau, Jürgen Popp, Bettina Löffler, Ute Neugebauer. Correlation of crystal violet biofilm test results of Staphylococcus aureus clinical isolates with Raman spectroscopic read‐out. Journal of Raman Spectroscopy. 2021; ():1.
Chicago/Turabian StyleChristina Ebert; Lorena Tuchscherr; Nancy Unger; Christine Pöllath; Frederike Gladigau; Jürgen Popp; Bettina Löffler; Ute Neugebauer. 2021. "Correlation of crystal violet biofilm test results of Staphylococcus aureus clinical isolates with Raman spectroscopic read‐out." Journal of Raman Spectroscopy , no. : 1.
Staphylococcus aureus is an opportunistic and versatile pathogen that can cause several diseases, which range from acute and destructive, to chronic and difficult-to-treat infections
Bettina Löffler; Lorena Tuchscherr. Staphylococcus aureus Toxins: Promoter or Handicap during Infection? Toxins 2021, 13, 287 .
AMA StyleBettina Löffler, Lorena Tuchscherr. Staphylococcus aureus Toxins: Promoter or Handicap during Infection? Toxins. 2021; 13 (4):287.
Chicago/Turabian StyleBettina Löffler; Lorena Tuchscherr. 2021. "Staphylococcus aureus Toxins: Promoter or Handicap during Infection?" Toxins 13, no. 4: 287.
A large proportion of clinical S. aureus isolates that carry an inactive Agr system are associated with persistent infection that is difficult to treat. Once S. aureus is inside the bloodstream, it can cross the endothelial barrier and invade almost every organ in the human body. Endothelial cells can either be lysed by this pathogen or they serve as a niche for its intracellular long-term survival. Following phagocytosis, several vesicles such as phagosomes and autophagosomes, target intracellular S. aureus for elimination. S. aureus can escape from these vesicles into the host cytoplasm through the activation of phenol-soluble modulins (PSMs) αβ. Thereafter, it replicates and lyses the host cell to disseminate to adjacent tissues. Herein we demonstrate that staphylococcal strains which lack the expression of PSMs employ an alternative pathway to better persist within endothelial cells. The intracellular survival of S. aureus is associated with the co-localization of the autophagy marker LC3. In cell culture infection models, we found that the absence of psmαβ decreased the host cell lysis and increased staphylococcal long-term survival. This study explains the positive selection of agr-negative strains that lack the expression of psmαβ in chronic infection due to their advantage in surviving and evading the clearance system of the host.
Anke Siegmund; Muhammad Awais Afzal; Felix Tetzlaff; Daniela Keinhörster; Fabio Gratani; Kerstin Paprotka; Martin Westermann; Sandor Nietzsche; Christiane Wolz; Martin Fraunholz; Christian A. Hübner; Bettina Löffler; Lorena Tuchscherr. Intracellular persistence of Staphylococcus aureus in endothelial cells is promoted by the absence of phenol-soluble modulins. Virulence 2021, 12, 1186 -1198.
AMA StyleAnke Siegmund, Muhammad Awais Afzal, Felix Tetzlaff, Daniela Keinhörster, Fabio Gratani, Kerstin Paprotka, Martin Westermann, Sandor Nietzsche, Christiane Wolz, Martin Fraunholz, Christian A. Hübner, Bettina Löffler, Lorena Tuchscherr. Intracellular persistence of Staphylococcus aureus in endothelial cells is promoted by the absence of phenol-soluble modulins. Virulence. 2021; 12 (1):1186-1198.
Chicago/Turabian StyleAnke Siegmund; Muhammad Awais Afzal; Felix Tetzlaff; Daniela Keinhörster; Fabio Gratani; Kerstin Paprotka; Martin Westermann; Sandor Nietzsche; Christiane Wolz; Martin Fraunholz; Christian A. Hübner; Bettina Löffler; Lorena Tuchscherr. 2021. "Intracellular persistence of Staphylococcus aureus in endothelial cells is promoted by the absence of phenol-soluble modulins." Virulence 12, no. 1: 1186-1198.
Staphylococcus aureus is able to survive within host cells by switching its phenotype to the small-colony variant (SCV) phenotype. The emergence of SCVs is associated with the development of persistent infections, which may be both chronic and recurrent. This slow-growing subpopulation of S. aureus forms small colonies on solid-medium agar, is induced within host cells, presents a non-homogenous genetic background, has reduced expression of virulence factors and presents a variable phenotype (stable or unstable). While virtually all SCVs isolated from clinical specimens can revert to the parental state with rapid growth, the stable SCVs recovered in clinical specimens have been found to contain specific mutations in metabolic pathways. In contrast, other non-stable SCVs are originated from regulatory mechanisms involving global regulators (e.g., sigB, sarA, and agr) or other non-defined mutations. One major characteristic of SCVs was the observation that SCVs were recovered from five patients with infections that could persist for decades. In these five cases, the SCVs had defects in electron transport. This linked persistent infections with SCVs. The term “persistent infection” is a clinical term wherein bacteria remain in the host for prolonged periods of time, sometimes with recurrent infection, despite apparently active antibiotics. These terms were described in vitro where bacteria remain viable in liquid culture medium in the presence of antibiotics. These bacteria are called “persisters”. While SCVs can be persisters in liquid culture, not all persisters are SCVs. One mechanism associated with the metabolically variant SCVs is the reduced production of virulence factors. SCVs have consistently shown reduced levels of RNAIII, a product of the accessory gene regulatory (agrBDCA) locus that controls a quorum-sensing system and regulates the expression of a large number of virulence genes. Reduced Agr acitivity is associated with enhanced survival of SCVs within host cells. In this review, we examine the impact of the SCVs with altered metabolic pathways on agr, and we draw distinctions with other types of SCVs that emerge within mammalian cells with prolonged infection.
Lorena Tuchscherr; Bettina Löffler; Richard A. Proctor. Persistence of Staphylococcus aureus: Multiple Metabolic Pathways Impact the Expression of Virulence Factors in Small-Colony Variants (SCVs). Frontiers in Microbiology 2020, 11, 1028 .
AMA StyleLorena Tuchscherr, Bettina Löffler, Richard A. Proctor. Persistence of Staphylococcus aureus: Multiple Metabolic Pathways Impact the Expression of Virulence Factors in Small-Colony Variants (SCVs). Frontiers in Microbiology. 2020; 11 ():1028.
Chicago/Turabian StyleLorena Tuchscherr; Bettina Löffler; Richard A. Proctor. 2020. "Persistence of Staphylococcus aureus: Multiple Metabolic Pathways Impact the Expression of Virulence Factors in Small-Colony Variants (SCVs)." Frontiers in Microbiology 11, no. : 1028.
Massive neutrophil infiltration is an early key event in infectious inflammation, accompanied by chemotactic leukotriene (LT)B4 generation. LTB4 biosynthesis is mediated by 5-lipoxygenase (5-LOX), but which pathogenic factors cause 5-LOX activation during bacterial infections is elusive. Here, we reveal staphylococcal exotoxins as 5-LOX activators. Conditioned medium of wild-type Staphylococcus aureus but not of exotoxin-deficient strains induced 5-LOX activation in transfected HEK293 cells. Two different staphylococcal exotoxins mimicked the effects of S. aureus-conditioned medium: (1) the pore-forming toxin α-hemolysin and (2) amphipathic α-helical phenol-soluble modulin (PSM) peptides. Interestingly, in human neutrophils, 5-LOX activation was exclusively evoked by PSMs, which was prevented by the selective FPR2/ALX receptor antagonist WRW4. 5-LOX activation by PSMs was confirmed in vivo as LT formation in infected paws of mice was impaired in response to PSM-deficient S. aureus. Conclusively, exotoxins from S. aureus are potent pathogenic factors that activate 5-LOX and induce LT formation in neutrophils.
Erik Romp; Vandana Arakandy; Jana Fischer; Christiane Wolz; Anke Siegmund; Bettina Löffler; Lorena Tuchscherr; Oliver Werz; Ulrike Garscha. Exotoxins from Staphylococcus aureus activate 5-lipoxygenase and induce leukotriene biosynthesis. Cellular and Molecular Life Sciences 2019, 77, 3841 -3858.
AMA StyleErik Romp, Vandana Arakandy, Jana Fischer, Christiane Wolz, Anke Siegmund, Bettina Löffler, Lorena Tuchscherr, Oliver Werz, Ulrike Garscha. Exotoxins from Staphylococcus aureus activate 5-lipoxygenase and induce leukotriene biosynthesis. Cellular and Molecular Life Sciences. 2019; 77 (19):3841-3858.
Chicago/Turabian StyleErik Romp; Vandana Arakandy; Jana Fischer; Christiane Wolz; Anke Siegmund; Bettina Löffler; Lorena Tuchscherr; Oliver Werz; Ulrike Garscha. 2019. "Exotoxins from Staphylococcus aureus activate 5-lipoxygenase and induce leukotriene biosynthesis." Cellular and Molecular Life Sciences 77, no. 19: 3841-3858.
Staphylococcus aureus has acquired resistance to antibiotics since their first use. The S. aureus protein NorA, an efflux pump belonging to the major facilitator superfamily (MFS), contributes to resistance to fluoroquinolones (e.g., ciprofloxacin), biocides, dyes, quaternary ammonium compounds, and antiseptics. Different compounds have been identified as potential efflux pump inhibitors (EPIs) of NorA that result in increased intracellular concentration of antibiotics, restoring their antibacterial activity and cell susceptibility. However, none of the currently known EPIs have been approved for clinical use, probably due to their toxicity profiles. In the present study, we screened approved drugs for possible efflux pump inhibition. By screening a compound library of approximately 1200 different drugs, we identified nilotinib, a tyrosine kinase inhibitor, as showing the best efflux pump inhibitory activity, with a fractional inhibitory concentration index of 0.1875, indicating synergism with ciprofloxacin, and a minimum effective concentration as low as 0.195 μM. Moreover, at 0.39 μM, nilotinib, in combination with 8 μg/mL of ciprofloxacin, led to a significant reduction in biofilm formation and preformed mature biofilms. This is the first description of an approved drug that can be used as an efflux pump inhibitor and to reduce biofilms formation at clinically achievable concentrations.
Saskia Zimmermann; Mareike Klinger-Strobel; Jürgen A. Bohnert; Sindy Wendler; Jürgen Rödel; Mathias W. Pletz; Bettina Löffler; Lorena Tuchscherr. Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation. Frontiers in Microbiology 2019, 10, 2762 .
AMA StyleSaskia Zimmermann, Mareike Klinger-Strobel, Jürgen A. Bohnert, Sindy Wendler, Jürgen Rödel, Mathias W. Pletz, Bettina Löffler, Lorena Tuchscherr. Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation. Frontiers in Microbiology. 2019; 10 ():2762.
Chicago/Turabian StyleSaskia Zimmermann; Mareike Klinger-Strobel; Jürgen A. Bohnert; Sindy Wendler; Jürgen Rödel; Mathias W. Pletz; Bettina Löffler; Lorena Tuchscherr. 2019. "Clinically Approved Drugs Inhibit the Staphylococcus aureus Multidrug NorA Efflux Pump and Reduce Biofilm Formation." Frontiers in Microbiology 10, no. : 2762.
Staphylococcus aureus colonizes epithelial surfaces, but it can also cause severe infections. The aim of this work was to investigate whether bacterial virulence correlates with defined types of tissue infections. For this, we collected 10–12 clinical S. aureus strains each from nasal colonization, and from patients with endoprosthesis infection, hematogenous osteomyelitis, and sepsis. All strains were characterized by genotypic analysis, and by the expression of virulence factors. The host–pathogen interaction was studied through several functional assays in osteoblast cultures. Additionally, selected strains were tested in a murine sepsis/osteomyelitis model. We did not find characteristic bacterial features for the defined infection types; rather, a wide range in all strain collections regarding cytotoxicity and invasiveness was observed. Interestingly, all strains were able to persist and to form small colony variants (SCVs). However, the low-cytotoxicity strains survived in higher numbers, and were less efficiently cleared by the host than the highly cytotoxic strains. In summary, our results indicate that not only destructive, but also low-cytotoxicity strains are able to induce infections. The low-cytotoxicity strains can successfully survive, and are less efficiently cleared from the host than the highly cytotoxic strains, which represent a source for chronic infections. The understanding of this interplay/evolution between the host and the pathogen during infection, with specific attention towards low-cytotoxicity isolates, will help to optimize treatment strategies for invasive and therapy-refractory infection courses.
Lorena Tuchscherr; Christine Pöllath; Anke Siegmund; Stefanie Deinhardt-Emmer; Verena Hoerr; Carl-Magnus Svensson; Marc Thilo Figge; Stefan Monecke; Bettina Löffler. Clinical S. aureus Isolates Vary in Their Virulence to Promote Adaptation to the Host. Toxins 2019, 11, 135 .
AMA StyleLorena Tuchscherr, Christine Pöllath, Anke Siegmund, Stefanie Deinhardt-Emmer, Verena Hoerr, Carl-Magnus Svensson, Marc Thilo Figge, Stefan Monecke, Bettina Löffler. Clinical S. aureus Isolates Vary in Their Virulence to Promote Adaptation to the Host. Toxins. 2019; 11 (3):135.
Chicago/Turabian StyleLorena Tuchscherr; Christine Pöllath; Anke Siegmund; Stefanie Deinhardt-Emmer; Verena Hoerr; Carl-Magnus Svensson; Marc Thilo Figge; Stefan Monecke; Bettina Löffler. 2019. "Clinical S. aureus Isolates Vary in Their Virulence to Promote Adaptation to the Host." Toxins 11, no. 3: 135.
Staphylococcus aureus is the most frequent pathogen causing diabetic foot infections. Here, we investigated the degree of bacterial virulence required to establish invasive tissue infections in diabetic organisms. Staphylococcal isolates from diabetic and non-diabetic foot ulcers were tested for their virulence in in vitro functional assays of host cell invasion and cytotoxicity. Isolates from diabetes mellitus type I/II patients exhibited less virulence than isolates from non-diabetic patients, but were nevertheless able to establish severe infections. In some cases, non-invasive isolates were detected deep within diabetic wounds, even though the strains were non-pathogenic in cell culture models. Testing of defined isolates in murine footpad injection models revealed that both low- and high-virulent bacterial strains persisted in higher numbers in diabetic compared to non-diabetic hosts, suggesting that hyperglycemia favors bacterial survival. Additionally, the bacterial load was higher in NOD mice, which have a compromised immune system, compared to C57Bl/6 mice. Our results reveal that high as well as low-virulent staphylococcal strains are able to cause soft tissue infections and to persist in diabetic humans and mice, suggesting a reason for the frequent and endangering infections in patients with diabetes.
Lorena Tuchscherr; èva Korpos; Hélène Van De Vyver; Clais Findeisen; Salome Kherkheulidze; Anke Siegmund; Stefanie Deinhardt-Emmer; Olaf Bach; Martin Rindert; Alexander Mellmann; Cord Sunderkötter; Georg Peters; Lydia Sorokin; Bettina Löffler. Staphylococcus aureus requires less virulence to establish an infection in diabetic hosts. International Journal of Medical Microbiology 2018, 308, 761 -769.
AMA StyleLorena Tuchscherr, èva Korpos, Hélène Van De Vyver, Clais Findeisen, Salome Kherkheulidze, Anke Siegmund, Stefanie Deinhardt-Emmer, Olaf Bach, Martin Rindert, Alexander Mellmann, Cord Sunderkötter, Georg Peters, Lydia Sorokin, Bettina Löffler. Staphylococcus aureus requires less virulence to establish an infection in diabetic hosts. International Journal of Medical Microbiology. 2018; 308 (7):761-769.
Chicago/Turabian StyleLorena Tuchscherr; èva Korpos; Hélène Van De Vyver; Clais Findeisen; Salome Kherkheulidze; Anke Siegmund; Stefanie Deinhardt-Emmer; Olaf Bach; Martin Rindert; Alexander Mellmann; Cord Sunderkötter; Georg Peters; Lydia Sorokin; Bettina Löffler. 2018. "Staphylococcus aureus requires less virulence to establish an infection in diabetic hosts." International Journal of Medical Microbiology 308, no. 7: 761-769.
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
Jennifer Geraci; Svetlana Neubauer; Christine Pöllath; Uwe Hansen; Fabio Rizzo; Christoph Krafft; Martin Westermann; Muzaffar Hussain; Georg Peters; Mathias W. Pletz; Bettina Löffler; Oliwia Makarewicz; Lorena Tuchscherr. Author Correction: The Staphylococcus aureus extracellular matrix protein (Emp) has a fibrous structure and binds to different extracellular matrices. Scientific Reports 2018, 8, 8396 .
AMA StyleJennifer Geraci, Svetlana Neubauer, Christine Pöllath, Uwe Hansen, Fabio Rizzo, Christoph Krafft, Martin Westermann, Muzaffar Hussain, Georg Peters, Mathias W. Pletz, Bettina Löffler, Oliwia Makarewicz, Lorena Tuchscherr. Author Correction: The Staphylococcus aureus extracellular matrix protein (Emp) has a fibrous structure and binds to different extracellular matrices. Scientific Reports. 2018; 8 (1):8396.
Chicago/Turabian StyleJennifer Geraci; Svetlana Neubauer; Christine Pöllath; Uwe Hansen; Fabio Rizzo; Christoph Krafft; Martin Westermann; Muzaffar Hussain; Georg Peters; Mathias W. Pletz; Bettina Löffler; Oliwia Makarewicz; Lorena Tuchscherr. 2018. "Author Correction: The Staphylococcus aureus extracellular matrix protein (Emp) has a fibrous structure and binds to different extracellular matrices." Scientific Reports 8, no. 1: 8396.
The extracellular matrix protein Emp of Staphylococcus aureus is a secreted adhesin that mediates interactions between the bacterial surface and extracellular host structures. However, its structure and role in staphylococcal pathogenesis remain unknown. Using multidisciplinary approaches, including circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy, transmission electron (TEM) and immunogold transmission electron microscopy, functional ELISA assays and in silico techniques, we characterized the Emp protein. We demonstrated that Emp and its truncated forms bind to suprastructures in human skin, cartilage or bone, among which binding activity seems to be higher for skin compounds. The binding domain is located in the C-terminal part of the protein. CD spectroscopy revealed high contents of β-sheets (39.58%) and natively disordered structures (41.2%), and TEM suggested a fibrous structure consisting of Emp polymers. The N-terminus seems to be essential for polymerization. Due to the uncommonly high histidine content, we suggest that Emp represents a novel type of histidine-rich protein sharing structural similarities to leucine-rich repeats proteins as predicted by the I-TASSER algorithm. These new findings suggest a role of Emp in infections of deeper tissue and open new possibilities for the development of novel therapeutic strategies.
Jennifer Geraci; Svetlana Neubauer; Christine Pöllath; Uwe Hansen; Fabio Rizzo; Christoph Krafft; Martin Westermann; Muzaffar Hussain; Georg Peters; Mathias W. Pletz; Bettina Löffler; Oliwia Makarewicz; Lorena Tuchscherr. The Staphylococcus aureus extracellular matrix protein (Emp) has a fibrous structure and binds to different extracellular matrices. Scientific Reports 2017, 7, 1 -14.
AMA StyleJennifer Geraci, Svetlana Neubauer, Christine Pöllath, Uwe Hansen, Fabio Rizzo, Christoph Krafft, Martin Westermann, Muzaffar Hussain, Georg Peters, Mathias W. Pletz, Bettina Löffler, Oliwia Makarewicz, Lorena Tuchscherr. The Staphylococcus aureus extracellular matrix protein (Emp) has a fibrous structure and binds to different extracellular matrices. Scientific Reports. 2017; 7 (1):1-14.
Chicago/Turabian StyleJennifer Geraci; Svetlana Neubauer; Christine Pöllath; Uwe Hansen; Fabio Rizzo; Christoph Krafft; Martin Westermann; Muzaffar Hussain; Georg Peters; Mathias W. Pletz; Bettina Löffler; Oliwia Makarewicz; Lorena Tuchscherr. 2017. "The Staphylococcus aureus extracellular matrix protein (Emp) has a fibrous structure and binds to different extracellular matrices." Scientific Reports 7, no. 1: 1-14.
Staphylococcus aureus is a major pathogen causing bone infections that can become chronic and difficult to treat. Recently, we described the mechanism employed by S. aureus to switch to small colony variants (SCVs) and trigger intracellular bacterial persistence through the global stress regulator SigB. Here, we studied the role of SigB in the formation of chronic osteomyelitis. We used a murine hematogenous osteomyelitis model, where the mice were infected via the tail vein and subsequently developed chronic osteomyelitis. Mice were infected with S. aureus LS1, LS1ΔsigB and LS1ΔsigB complemented and kidney and bone tissues were analyzed six weeks after infection. S. aureus LS1ΔsigB formed a high rate of abscesses in kidneys, but the bacterial loads and the weight loss of the animals were lower in comparison with animals infected with the wild type and the complemented strain, indicating a more rapid and efficient bacterial clearing by the host immune system. Moreover, the sigB-mutant was not able to form SCV phenotypes either in kidney or in bone tissue. Our results demonstrate that staphylococcal SigB is important to avoid bacterial elimination by the host immune response, establish a bone infection and mediate bacterial adaptation (SCV-formation) for persistent infections
Lorena Tuchscherr; Jennifer Geraci; Bettina Löffler. Staphylococcus aureus Regulator Sigma B is Important to Develop Chronic Infections in Hematogenous Murine Osteomyelitis Model. Pathogens 2017, 6, 31 .
AMA StyleLorena Tuchscherr, Jennifer Geraci, Bettina Löffler. Staphylococcus aureus Regulator Sigma B is Important to Develop Chronic Infections in Hematogenous Murine Osteomyelitis Model. Pathogens. 2017; 6 (3):31.
Chicago/Turabian StyleLorena Tuchscherr; Jennifer Geraci; Bettina Löffler. 2017. "Staphylococcus aureus Regulator Sigma B is Important to Develop Chronic Infections in Hematogenous Murine Osteomyelitis Model." Pathogens 6, no. 3: 31.
Host cell invasion is a major feature of Staphylococcus aureus and contributes to infection development. The intracellular metabolically active bacteria can induce host cell activation and death but they can also persist for long time periods. In this study a comparative analysis was performed of different well-characterized S. aureus strains in their interaction with a variety of host cell types. Staphylococcus aureus (strains 6850, USA300, LS1, SH1000, Cowan1) invasion was compared in different human cell types (epithelial and endothelial cells, keratinocytes, fibroblasts, osteoblasts). The number of intracellular bacteria was determined, cell inflammation was investigated, as well as cell death and phagosomal escape of bacteria. To explain strain-dependent differences in the secretome, a proteomic approach was used. Barrier cells took up high amounts of bacteria and were killed by aggressive strains. These strains expressed high levels of toxins, and possessed the ability to escape from phagolysosomes. Osteoblasts and keratinocytes ingested less bacteria, and were not killed, even though the primary osteoblasts were strongly activated by S. aureus. In all cell types S. aureus was able to persist. Strong differences in uptake, cytotoxicity, and inflammatory response were observed between primary cells and their corresponding cell lines, demonstrating that cell lines reflect only partially the functions and physiology of primary cells. This study provides a contribution for a better understanding of the pathomechanisms of S. aureus infections. The proteomic data provide important basic knowledge on strains commonly used in the analysis of S. aureus-host cell interaction.
M. Strobel; H. Pförtner; L. Tuchscherr; Uwe Völker; F. Schmidt; N. Kramko; H.-J. Schnittler; M.J. Fraunholz; B. Löffler; G. Peters; S. Niemann. Post-invasion events after infection with Staphylococcus aureus are strongly dependent on both the host cell type and the infecting S. aureus strain. Clinical Microbiology and Infection 2016, 22, 799 -809.
AMA StyleM. Strobel, H. Pförtner, L. Tuchscherr, Uwe Völker, F. Schmidt, N. Kramko, H.-J. Schnittler, M.J. Fraunholz, B. Löffler, G. Peters, S. Niemann. Post-invasion events after infection with Staphylococcus aureus are strongly dependent on both the host cell type and the infecting S. aureus strain. Clinical Microbiology and Infection. 2016; 22 (9):799-809.
Chicago/Turabian StyleM. Strobel; H. Pförtner; L. Tuchscherr; Uwe Völker; F. Schmidt; N. Kramko; H.-J. Schnittler; M.J. Fraunholz; B. Löffler; G. Peters; S. Niemann. 2016. "Post-invasion events after infection with Staphylococcus aureus are strongly dependent on both the host cell type and the infecting S. aureus strain." Clinical Microbiology and Infection 22, no. 9: 799-809.
Objectives Staphylococcus aureus osteomyelitis often develops to chronicity despite antimicrobial treatments that have been found to be susceptible in in vitro tests. The complex infection strategies of S. aureus, including host cell invasion and intracellular persistence via the formation of dynamic small colony variant (SCV) phenotypes, could be responsible for therapy-refractory infection courses. Methods To analyse the efficacy of antibiotics in the acute and chronic stage of bone infections, we established long-term in vitro and in vivo osteomyelitis models. Antibiotics that were tested include β-lactams, fluoroquinolones, vancomycin, linezolid, daptomycin, fosfomycin, gentamicin, rifampicin and clindamycin. Results Cell culture infection experiments revealed that all tested antibiotics reduced bacterial numbers within infected osteoblasts when treatment was started immediately, whereas some antibiotics lost their activity against intracellular persisting bacteria. Only rifampicin almost cleared infected osteoblasts in the acute and chronic stages. Furthermore, we detected that low concentrations of gentamicin, moxifloxacin and clindamycin enhanced the formation of SCVs, and these could promote chronic infections. Next, we treated a murine osteomyelitis model in the acute and chronic stages. Only rifampicin significantly reduced the bacterial load of bones in the acute phase, whereas cefuroxime and gentamicin were less effective and gentamicin strongly induced SCV formation. During chronicity none of the antimicrobial compounds tested showed a beneficial effect on bone deformation or reduced the numbers of persisting bacteria. Conclusions In all infection models rifampicin was most effective at reducing bacterial loads. In the chronic stage, particularly in the in vivo model, many tested compounds lost activity against persisting bacteria and some antibiotics even induced SCV formation.
Lorena Tuchscherr; Carolin Kreis; Verena Hoerr; L. Flint; Marie Hachmeister; J E Geraci; Sibylle Bremerstreck; Michael Kiehntopf; Eva Medina; M. Kribus; Michael J Raschke; M W Pletz; G J Peters; Bettina Loffler. Staphylococcus aureusdevelops increased resistance to antibiotics by forming dynamic small colony variants during chronic osteomyelitis. Journal of Antimicrobial Chemotherapy 2015, 71, 438 -448.
AMA StyleLorena Tuchscherr, Carolin Kreis, Verena Hoerr, L. Flint, Marie Hachmeister, J E Geraci, Sibylle Bremerstreck, Michael Kiehntopf, Eva Medina, M. Kribus, Michael J Raschke, M W Pletz, G J Peters, Bettina Loffler. Staphylococcus aureusdevelops increased resistance to antibiotics by forming dynamic small colony variants during chronic osteomyelitis. Journal of Antimicrobial Chemotherapy. 2015; 71 (2):438-448.
Chicago/Turabian StyleLorena Tuchscherr; Carolin Kreis; Verena Hoerr; L. Flint; Marie Hachmeister; J E Geraci; Sibylle Bremerstreck; Michael Kiehntopf; Eva Medina; M. Kribus; Michael J Raschke; M W Pletz; G J Peters; Bettina Loffler. 2015. "Staphylococcus aureusdevelops increased resistance to antibiotics by forming dynamic small colony variants during chronic osteomyelitis." Journal of Antimicrobial Chemotherapy 71, no. 2: 438-448.
Staphylococcus aureus is an important pathogen of severe invasive tissue infection, e.g. osteomyelitis that can develop to chronicity and become extremely difficult to treat. Recent research revealed that S. aureus can dynamically switch to small colony variants (SCVs) that are adapted bacterial phenotypes for long-term persistence. The underlying mechanisms of the bacterial switching and adaptation process are largely dependent on an intact Sigma B regulon. As SigB is known as a transcription factor that modulates the stress response of several Gram-positive bacteria, it is most likely required by the bacteria to cope with the intracellular stress conditions. Here, we demonstrate in a long-term infection model of human osteoblasts that S. aureus continuously upregulated the expression of SigB during intracellular persistence. The increased SigB expression was accompanied by upregulation of adhesins and downregulation of toxins, which are characteristics for SCV phenotypes. These data further stress the role of SigB during chronic infections that could be a novel target for preventive or therapeutic measures to avoid chronic infections.
Lorena Tuchscherr; Bettina Löffler. Staphylococcus aureus dynamically adapts global regulators and virulence factor expression in the course from acute to chronic infection. Current Genetics 2015, 62, 15 -17.
AMA StyleLorena Tuchscherr, Bettina Löffler. Staphylococcus aureus dynamically adapts global regulators and virulence factor expression in the course from acute to chronic infection. Current Genetics. 2015; 62 (1):15-17.
Chicago/Turabian StyleLorena Tuchscherr; Bettina Löffler. 2015. "Staphylococcus aureus dynamically adapts global regulators and virulence factor expression in the course from acute to chronic infection." Current Genetics 62, no. 1: 15-17.