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2. Contributors

Author

Abdollah, Maha R.A., primary, Ahmad, Mir Hilal, additional, Alcover-Sanchez, Berta, additional, Alfaro Rodríguez, Alfonso, additional, Ali, Marwa A., additional, Alkadhi, Karim A., additional, Auburger, Georg, additional, Banerjee, Meheli, additional, Baums, Christoph G., additional, Belan, Daria V., additional, Bleeser, Tom, additional, Bobrovskaya, Larisa, additional, Bolay, Hayrunnisa, additional, Brandenburg, Joline E., additional, Budni, Josiane, additional, Burnsed, Jennifer, additional, Cadiz, Antonio, additional, Carlin, Katherine, additional, Chavez-Valdez, Raul, additional, Chen, Win Ning, additional, Coq, Jacques-Olivier, additional, Crocker, Stephen J., additional, Cubelos, Beatriz, additional, Darshini, I.S., additional, de Buhr, Nicole, additional, Debatisse, Justine, additional, Deng, Isaac, additional, Deprest, Jan, additional, Devroe, Sarah, additional, dos Santos, Maria Laura Cecconi, additional, Doszyn, Olga, additional, Dulski, Tomasz, additional, Eker, Omer Faruk, additional, Ekimova, Irina V., additional, Falquetto, Barbara, additional, Fernández, Ana, additional, Fogarty, Matthew J., additional, Fouda, Abdelrahman Y., additional, Gandía, Luis, additional, García, Antonio G., additional, González Maciel, Angélica, additional, Grandgirard, Denis, additional, Grayson, Bernadette E., additional, Greenberg, David A., additional, Gulyaeva, Natalia, additional, Gupta, Sangeetha, additional, Gürer, Bora, additional, Guzmán-Quevedo, Omar, additional, Gyamfi, Daniel, additional, Hamimi, Sarah, additional, He, Junqiu, additional, Hong, Sung-Ha, additional, Ida, Hiroyuki, additional, Jantrapirom, Salinee, additional, Jantzie, Lauren L., additional, Kadzhaya, Mykola, additional, Kanungo, Jyotshna, additional, Kaur, Ginpreet, additional, Keller, Gabriela Serafim, additional, Kelliny, Sally, additional, Kokiko-Cochran, Olga N., additional, Komoltsev, Ilia, additional, Kumar, P. Pramod, additional, Lacerda, Diego Cabral, additional, Lambert, Geoffrey A., additional, Lapshina, Ksenia V., additional, Largent-Milnes, Tally M., additional, Le, Ngoc Dung, additional, Leib, Stephen L., additional, Levine, Aidan A., additional, Li, Lulin, additional, Liktor-Busa, Erika, additional, Liu, Fang, additional, Liu, Sufang, additional, Luo, Jian, additional, Manhães-de-Castro, Raul, additional, McBride, Devin W., additional, Medeiros, Eduarda Behenck, additional, Meurer, Marita, additional, Miller, Brandon A., additional, Mondal, Amal Chandra, additional, Moreira, Thiago S., additional, Narayanan, S. Priya, additional, Nguyen, Andy, additional, Panteleichuk, Andrii, additional, Paricio, Nuria, additional, Pastukhov, Yuri F., additional, Patel, Vinood B., additional, Pedachenko, Eugene, additional, Perouansky, Misha, additional, Petriv, Taras, additional, Piccolo, Luca Lo, additional, Prashanth, K.V. Harish, additional, Preedy, Victor R., additional, Puig, Cristina, additional, Rajendram, Rajkumar, additional, Ramasamy, Ramalakshmi, additional, Ramasamy, Santhamani, additional, Ramirez-Lee, Manuel Alejandro, additional, Ray, Trenton J., additional, Rempel, Lisienny Campoli Tono, additional, Renz, Miriam, additional, Rex, Steffen, additional, Reynoso Robles, Rafael, additional, Ricci, Susanna, additional, Rieger, Sandra, additional, Robinson, Shenandoah, additional, Romero Velázquez, Rosa María, additional, Rümmler, Robert, additional, Sanz, Francisco José, additional, Savosko, Serhii, additional, Sedky, Nada K., additional, Sen, Nesli-Ece, additional, Shaikh, Mohd. Farooq, additional, Shan, Shengshuai, additional, Sharma, Uma, additional, Shmeleva, Anna, additional, Sieck, Gary C., additional, Siegert, Pascal, additional, Smith, Allie M., additional, Smith, Phillip P., additional, Solana-Manrique, Cristina, additional, Soulas, Emmanuelle Canet, additional, Subba, Rhea, additional, Subbian, Selvakumar, additional, Takakura, Ana C., additional, Talpos, John C., additional, Tam, Kin Yip, additional, Tao, Feng, additional, Tapp, Zoe, additional, Thawkar, Baban S, additional, Tolba, Mai F., additional, Toscano, Ana Elisa, additional, Tsuji, Masahiro, additional, Valenzuela, Ignacio, additional, Van de Velde, Marc, additional, Van der Veeken, Lennart, additional, Velíšek, Libor, additional, Velíšková, Jana, additional, Visco, Diego Bulcão, additional, Vita, Sydney M., additional, von Köckritz-Blickwede, Maren, additional, Vuralli, Doga, additional, Walters, Jennifer L., additional, Wassarman, David A., additional, Wateau, Océane, additional, Yamaguchi, Masamitsu, additional, Yoshida, Hideki, additional, Zhou, Xin-Fu, additional, and Zmorzynska, Justyna, additional

Published
2023
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4. Neutrophil extracellular traps in CSF and serum of dogs with steroid-responsive meningitis-arteritis

Author

Wohlsein, Jan Christian, primary, Meurer, Marita, additional, Mörgelin, Matthias, additional, Nessler, Jasmin Nicole, additional, Flegel, Thomas, additional, Schenk, Henning Christian, additional, Jurina, Konrad, additional, Rentmeister, Kai, additional, Fischer, Andrea, additional, Gödde, Thomas, additional, Baumgärtner, Wolfgang, additional, von Köckritz-Blickwede, Maren, additional, and Tipold, Andrea, additional

Published
2024
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6. Alteration of cholesterol content and oxygen level in intestinal organoids after infection with Staphylococcus aureus

Author

Mergani, AhmedElmontaser, primary, Meurer, Marita, additional, Wiebe, Elena, additional, Dümmer, Katrin, additional, Wirz, Katrin, additional, Lehmann, Judith, additional, Brogden, Graham, additional, Schenke, Maren, additional, Künnemann, Katrin, additional, Naim, Hassan Y., additional, Grassl, Guntram A., additional, von Köckritz‐Blickwede, Maren, additional, and Seeger, Bettina, additional

Published
2023
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11. Mycobacterium tuberculosis PE/ PPE proteins enhance the production of reactive oxygen species and formation of neutrophil extracellular traps.

Author

García-Bengoa, Maria, Meurer, Marita, Stehr, Matthias, Elamin, Ayssar A., Singh, Mahavir, Oehlmann, Wulf, Morgelin, Matthias, and von Köckritz-Blickwede, Maren

Subjects
MYCOBACTERIA, MYCOBACTERIUM tuberculosis, REACTIVE oxygen species, CONFOCAL fluorescence microscopy, NEUTROPHILS, PERSONAL protective equipment, OXYGEN consumption
Abstract

Introduction: Neutrophil granulocytes predominate in the lungs of patients infected with Mycobacterium tuberculosis (Mtb) in earlier stages of the disease. During infection, neutrophils release neutrophil extracellular traps (NETs), an antimicrobial mechanism by which a DNA-backbone spiked with antimicrobial components traps the mycobacteria. However, the specific mycobacterial factors driving NET formation remain unclear. Proteins from the proline-glutamic acid (PE)/proline-proline-glutamic acid (PPE) family are critical to Mtb pathophysiology and virulence. Methods: Here, we investigated NET induction by PE18, PPE26, and PE31 in primary human blood-derived neutrophils. Neutrophils were stimulated with the respective proteins for 3h, and NET formation was subsequently assessed using confocal fluorescence microscopy. Intracellular ROS levels and cell necrosis were estimated by flow cytometry. Additionally, the influence of phorbol-12-myristate-13-acetate (PMA), a known NADPH oxidase enhancer, on NET formation was examined. Neutrophil integrity following incubation with the PE/PPE proteins was evaluated using transmission electron microscopy. Results: For the first time, we report that stimulation of primary human blood-derived neutrophils with Mtb proteins PE18, PPE26, and PE31 resulted in the formation of NETs, which correlated with an increase in intracellular ROS levels. Notably, the presence of PMA further amplified this effect. Following incubation with the PE/PPE proteins, neutrophils were found to remain viable and structurally intact, as verified through transmission electron microscopy, indicating the occurrence of vital NET formation. Discussion: These findings offer valuable insights that contribute to a better understanding of host-pathogen interactions during Mtb infection. Moreover, they underscore the significance of these particular Mtb antigens in triggering NET formation, representing a distinctive and previously unrecognized function of PE/PPE antigens. [ABSTRACT FROM AUTHOR]

Published
2023
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12. Companion Animals in Zoonoses Research – Ethical Considerations.

Author

Persson, Kirsten, Schulz, Claudia, Deckers, Jan, Pilchová, Veronika, Wirz, Katrin, Hartnack, Sonja, Meurer, Marita, Richter, Armina, Wystub, Paula, van Herten, Joost, von Köckritz-Blickwede, Maren, Fossati, Paola, and Kunzmann, Peter

Subjects
PETS, LABORATORY animals, VETERINARY medicine, BIOETHICS, ZOONOSES
Abstract

Non-human animals are commonly classified according to their "role", such as "livestock", "wild" or "companion" animals. But what if those classifications overlap? This article presents a report of the retreat week "ZooCan – Zoonoses of companion animals as case study for animal ethics" at the University of Veterinary Medicine Hannover, Germany, in November 2022. The workshop included participants from different European countries with interdisciplinary backgrounds (animal law, bioethics, epidemiology, philosophy, biology and veterinary medicine). We address ethically relevant issues that emerge when companion animals are used as research animals, particularly in zoonoses research. The outcomes of the multi-disciplinary approach are used to i) define criteria to classify "companion" and "research" animals, ii) provide guidance to overcome the challenges with classificational overlaps, iii) give insights into cutting-edge zoonoses research with an example of SARS-CoV-2 in cats, and iv) discuss animal ethics approaches with regard to classifications. [ABSTRACT FROM AUTHOR]

Published
2023
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13. Insights Into Immunothrombotic Mechanisms in Acute Stroke due to Vaccine-Induced Immune Thrombotic Thrombocytopenia

Author

de Buhr, Nicole, primary, Baumann, Tristan, additional, Werlein, Christopher, additional, Fingerhut, Leonie, additional, Imker, Rabea, additional, Meurer, Marita, additional, Götz, Friedrich, additional, Bronzlik, Paul, additional, Kühnel, Mark P., additional, Jonigk, Danny D., additional, Ernst, Johanna, additional, Leotescu, Andrei, additional, Gabriel, Maria M., additional, Worthmann, Hans, additional, Lichtinghagen, Ralf, additional, Tiede, Andreas, additional, von Köckritz-Blickwede, Maren, additional, Falk, Christine S., additional, Weissenborn, Karin, additional, Schuppner, Ramona, additional, and Grosse, Gerrit M., additional

Published
2022
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16. Development of Quality Control Ranges for Biocide Susceptibility Testing

Author

Schug, Angela R., Scholtzek, Anissa D., Turnidge, John, Meurer, Marita, Schwarz, Stefan, Feßler, Andrea T., and The Biocide Susceptibility Study Group

Subjects
Staphylococcus aureus, octenidine, Enterococcus hirae, 600 Technik, Medizin, angewandte Wissenschaften::630 Landwirtschaft::630 Landwirtschaft und verwandte Bereiche, 500 Naturwissenschaften und Mathematik::570 Biowissenschaften, Biologie::579 Mikroorganismen, Pilze, Algen, Pseudomonas aeruginosa, chlorhexidine, Escherichia coli, benzalkonium chloride, polyhexanide
Abstract

Every laboratory test needs validation by quality controls. For biocide susceptibility testing (BST), neither quality control (QC) strains nor QC ranges applicable to these strains are currently available. As QC strains, four well-defined laboratory reference strains (Staphylococcus aureus ATCC® 6538, Enterococcus hirae ATCC® 10541, Escherichia coli ATCC® 10536 and Pseudomonas aeruginosa ATCC® 15442), which have been used previously for biocide efficacy testing, were selected. In an interlaboratory trial with eleven participating laboratories, BST QC ranges should be developed for the aforementioned four strains and the four biocides benzalkonium chloride, chlorhexidine, octenidine and polyhexanide. The performance of three different lots of tryptic soy broth was explored using the broth microdilution method and the data were subsequently evaluated using the RangeFinder software. As a result, QC ranges were defined for all reference strain–biocide combinations, except for P. aeruginosa ATCC® 15442 with the two biocides chlorhexidine and polyhexanide. The development of the latter two QC ranges was not possible, due to the limited solubility of the biocides in the test range required for P. aeruginosa ATCC® 15442. The newly developed QC ranges comprise three to five dilution steps. The establishment of QC ranges will contribute to the validation of BST in the future.

Published
2022
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19. Additional file 8 of In vivo oxygen measurement in cerebrospinal fluid of pigs to determine physiologic and pathophysiologic oxygen values during CNS infections

Author

de Buhr, Nicole, Martens, Alexander, Meurer, Marita, Bonilla, Marta C., Söbbeler, Franz, Twele, Lara, Neudeck, Stephan, Wendt, Michael, Beineke, Andreas, Kästner, Sabine, and von Köckritz-Blickwede, Maren

Subjects
fluids and secretions, integumentary system, animal diseases
Abstract

Additional file 8. Table S6. Reisolation of the challenge strain from piglets after intravenous challenge with S. suis serotype 2.

Published
2021
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21. Additional file 6 of In vivo oxygen measurement in cerebrospinal fluid of pigs to determine physiologic and pathophysiologic oxygen values during CNS infections

Author

de Buhr, Nicole, Martens, Alexander, Meurer, Marita, Bonilla, Marta C., Söbbeler, Franz, Twele, Lara, Neudeck, Stephan, Wendt, Michael, Beineke, Andreas, Kästner, Sabine, and von Köckritz-Blickwede, Maren

Abstract

Additional file 6. Table S4. Analysis of various measurement cut-off's from all data in Fig 4d.

Published
2021
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22. Additional file 7 of In vivo oxygen measurement in cerebrospinal fluid of pigs to determine physiologic and pathophysiologic oxygen values during CNS infections

Author

de Buhr, Nicole, Martens, Alexander, Meurer, Marita, Bonilla, Marta C., Söbbeler, Franz, Twele, Lara, Neudeck, Stephan, Wendt, Michael, Beineke, Andreas, Kästner, Sabine, and von Köckritz-Blickwede, Maren

Subjects
inorganic chemicals, cardiovascular system, respiratory system, circulatory and respiratory physiology
Abstract

Additional file 7. Table S5. Individual pO2 values in CSF and blood and mean values per group.

Published
2021
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25. LPS Primes Brain Responsiveness to High Mobility Group Box-1 Protein

Author

Peek, Verena, primary, Harden, Lois M., additional, Damm, Jelena, additional, Aslani, Ferial, additional, Leisengang, Stephan, additional, Roth, Joachim, additional, Gerstberger, Rüdiger, additional, Meurer, Marita, additional, von Köckritz-Blickwede, Maren, additional, Schulz, Sabine, additional, Spengler, Bernhard, additional, and Rummel, Christoph, additional

Published
2021
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26. Antimicrobial Susceptibility Testing of Antimicrobial Peptides Requires New and Standardized Testing Structures

Author

Meurer, Marita, primary, O’Neil, Deborah A., additional, Lovie, Emma, additional, Simpson, Laura, additional, Torres, Marcelo D. T., additional, de la Fuente-Nunez, Cesar, additional, Angeles-Boza, Alfredo M., additional, Kleinsorgen, Christin, additional, Mercer, Derry K., additional, and von Köckritz-Blickwede, Maren, additional

Published
2021
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27. Comparing Cathelicidin Susceptibility of the Meningitis Pathogens Streptococcus suis and Escherichia coli in Culture Medium in Contrast to Porcine or Human Cerebrospinal Fluid

Author

Meurer, Marita, de Buhr, Nicole, Unger, Linn Meret, Bonilla, Marta C., Seele, Jana, Nau, Roland, Baums, Christoph G., Gutsmann, Thomas, Schwarz, Stefan, and von Köckritz-Blickwede, Maren

Subjects
Microbiology (medical), MIC, AMP, LL-37, PR-39, Streptococcus suis, Escherichia coli, cerebrospinal fluid (CSF), PR-39, Streptococcus suis, ddc:570, Escherichia coli, LL-37, cerebrospinal fluid (CSF), MIC, equipment and supplies, Microbiology, Original Research, AMP
Abstract

Host defense peptides or antimicrobial peptides (AMPs), e.g., cathelicidins, have recently been discussed as a potential new treatment option against bacterial infections. To test the efficacy of AMPs, standardized methods that closely mimic the physiological conditions at the site of infection are still needed. The aim of our study was to test the meningitis-causing bacteria Streptococcus suis and Escherichia coli for their susceptibility to cathelicidins in culture medium versus cerebrospinal fluid (CSF). Susceptibility testing was performed in analogy to the broth microdilution method described by the Clinical and Laboratory Standard Institute (CLSI) to determine minimum inhibitory concentrations (MICs) of antimicrobial agents. MICs were determined using cation-adjusted Mueller–Hinton broth (CA-MHB), lysogeny broth (LB), Roswell Park Memorial Institute medium (RPMI) or Dulbecco’s Modified Eagle’s Medium (DMEM) (the latter two supplemented with 5% CA-MHB or blood) and compared with MICs obtained in porcine or human CSF. Our data showed that MICs obtained in CA-MHB as recommended by CLSI do not reflect the MICs obtained in the physiological body fluid CSF. However, the MICs of clinical isolates of S. suis tested in RPMI medium supplemented with CA-MHB, were similar to those of the same strains tested in CSF. In contrast, the MICs in the human CSF for the tested E. coli K1 strain were higher compared to the RPMI medium and showed even higher values than in CA-MHB. This highlights the need for susceptibility testing of AMPs in a medium that closely mimics the clinically relevant conditions.

Published
2020

28. Analysis of Porcine Pro- and Anti-Inflammatory Cytokine Induction by S. suis In Vivo and In Vitro

Author

Hohnstein, Florian S., Meurer, Marita, de Buhr, Nicole, von Köckritz-Blickwede, Maren, Baums, Christoph G., Alber, Gottfried, and Schütze, Nicole

Subjects
pig, bacterial killing, S. suis, whole-blood model, PBMC, monocytes, interleukin-6, interleukin-10, tumor necrosis factor-alpha, lcsh:R, lcsh:Medicine, Article, ddc:570, pbmc, s. suis
Abstract

Weaning piglets are susceptible to the invasive Streptococcus (S.) suis infection, which can result in septicemia. The aim of this study was to investigate the cytokine profile induced upon S. suis infection of blood, to determine the cellular sources of those cytokines, and to study the potential effects of the induced cytokines on bacterial killing. We measured TNF-&alpha, IL-6, IFN-&gamma, IL-17A and IL-10 after an experimental intravenous infection with S. suis serotype 2 in vivo, and analyzed whole blood, peripheral blood mononuclear cells (PBMC) and separated leukocytes to identify the cytokine-producing cell type(s). In addition, we used a reconstituted whole blood assay to investigate the effect of TNF-&alpha, on bacterial killing in the presence of different S. suis-specific IgG levels. An increase in IL-6 and IL-10, but not in IFN-&gamma, or IL-17A, was observed in two of three piglets with pronounced bacteremia 16 to 20 h after infection, but not in piglets with controlled bacteremia. Our results confirmed previous findings that S. suis induces TNF-&alpha, and IL-6 and could demonstrate that TNF-&alpha, is produced by monocytes in vitro. We further found that IL-10 induction resulted in reduced secretion of TNF-&alpha, and IL-6. Rapid induction of TNF-&alpha, was, however, not crucial for in vitro bacterial killing, not even in the absence of specific IgG.

Published
2020

31. Role of Bacterial and Host DNases on Host-Pathogen Interaction during Streptococcus suis Meningitis

Author

Meurer, Marita, primary, Öhlmann, Sophie, additional, Bonilla, Marta C., additional, Valentin-Weigand, Peter, additional, Beineke, Andreas, additional, Hennig-Pauka, Isabel, additional, Schwerk, Christian, additional, Schroten, Horst, additional, Baums, Christoph G., additional, Köckritz-Blickwede, Maren von, additional, and de Buhr, Nicole, additional

Published
2020
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32. Comparing Cathelicidin Susceptibility of the Meningitis Pathogens Streptococcus suis and Escherichia coli in Culture Medium in Contrast to Porcine or Human Cerebrospinal Fluid

Author

Meurer, Marita, de Buhr, Nicole, Unger, Linn Meret, Bonilla, Marta C., Seele, Jana, Nau, Roland, Baums, Christoph G., Gutsmann, Thomas, Schwarz, Stefan, von Köckritz-Blickwede, Maren, Meurer, Marita, de Buhr, Nicole, Unger, Linn Meret, Bonilla, Marta C., Seele, Jana, Nau, Roland, Baums, Christoph G., Gutsmann, Thomas, Schwarz, Stefan, and von Köckritz-Blickwede, Maren

Abstract

Host defense peptides or antimicrobial peptides (AMPs), e.g., cathelicidins, have recently been discussed as a potential new treatment option against bacterial infections. To test the efficacy of AMPs, standardized methods that closely mimic the physiological conditions at the site of infection are still needed. The aim of our study was to test the meningitis-causing bacteria Streptococcus suis and Escherichia coli for their susceptibility to cathelicidins in culture medium versus cerebrospinal fluid (CSF). Susceptibility testing was performed in analogy to the broth microdilution method described by the Clinical and Laboratory Standard Institute (CLSI) to determine minimum inhibitory concentrations (MICs) of antimicrobial agents. MICs were determined using cation-adjusted Mueller–Hinton broth (CA-MHB), lysogeny broth (LB), Roswell Park Memorial Institute medium (RPMI) or Dulbecco’s Modified Eagle’s Medium (DMEM) (the latter two supplemented with 5% CA-MHB or blood) and compared with MICs obtained in porcine or human CSF. Our data showed that MICs obtained in CA-MHB as recommended by CLSI do not reflect the MICs obtained in the physiological body fluid CSF. However, the MICs of clinical isolates of S. suis tested in RPMI medium supplemented with CA-MHB, were similar to those of the same strains tested in CSF. In contrast, the MICs in the human CSF for the tested E. coli K1 strain were higher compared to the RPMI medium and showed even higher values than in CA-MHB. This highlights the need for susceptibility testing of AMPs in a medium that closely mimics the clinically relevant conditions.

Published
2019

33. Development and evaluation of a broth macrodilution method to determine the biocide susceptibility of bacteria

Author

Feßler, Andrea T., primary, Schug, Angela R., additional, Geber, Franziska, additional, Scholtzek, Anissa D., additional, Merle, Roswitha, additional, Brombach, Julian, additional, Hensel, Vivian, additional, Meurer, Marita, additional, Michael, Geovana Brenner, additional, Reinhardt, Mario, additional, Speck, Stephanie, additional, Truyen, Uwe, additional, and Schwarz, Stefan, additional

Published
2018
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34. IgM cleavage by Streptococcus suis reduces IgM bound to the bacterial surface and is a novel complement evasion mechanism

Author

Rungelrath, Viktoria, primary, Weiße, Christine, additional, Schütze, Nicole, additional, Müller, Uwe, additional, Meurer, Marita, additional, Rohde, Manfred, additional, Seele, Jana, additional, Valentin-Weigand, Peter, additional, Kirschfink, Michael, additional, Beineke, Andreas, additional, Schrödl, Wieland, additional, Bergmann, René, additional, and Baums, Christoph Georg, additional

Published
2018
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35. IgM cleavage by Streptococcus suisreduces IgM bound to the bacterial surface and is a novel complement evasion mechanism

Author

Rungelrath, Viktoria, Weiße, Christine, Schütze, Nicole, Müller, Uwe, Meurer, Marita, Rohde, Manfred, Seele, Jana, Valentin-Weigand, Peter, Kirschfink, Michael, Beineke, Andreas, Schrödl, Wieland, Bergmann, René, and Baums, Christoph Georg

Abstract

ABSTRACTStreptococcus suis(S. suis) causes meningitis, arthritis and endocarditis in piglets. The aim of this study was to characterize the IgM degrading enzyme of S. suis(IdeSsuis) and to investigate the role of IgM cleavage in evasion of the classical complement pathway and pathogenesis. Targeted mutagenesis of a cysteine in the putative active center of IdeSsuisabrogated IgM cleavage completely. In contrast to wt rIdeSsuis, point mutated rIdeSsuis_C195S did not reduce complement-mediated hemolysis indicating that complement inhibition by rIdeSsuisdepends on the IgM proteolytic activity. A S. suismutant expressing IdeSsuis_C195S did not reduce IgM labeling, whereas the wt and complemented mutant showed less IgM F(ab’)2 and IgM Fc antigen on the surface. IgM cleavage increased survival of S. suisin porcine blood ex vivoand mediated complement evasion as demonstrated by blood survival and C3 deposition assays including the comparative addition of rIdeSsuisand rIdeSsuis_C195S. However, experimental infection of piglets disclosed no significant differences in virulence between S. suiswt and isogenic mutants without IgM cleavage activity. This work revealed for the first time in vivolabeling of S. suiswith IgM in the cerebrospinal fluid of piglets with meningitis. In conclusion, this study classifies IdeSsuisas a cysteine protease and emphasizes the role of IgM cleavage for bacterial survival in porcine blood and complement evasion though IgM cleavage is not crucial for the pathogenesis of serotype 2 meningitis.

Published
2018
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36. Development of Quality Control Ranges for Biocide Susceptibility Testing.

Author

Schug AR, Scholtzek AD, Turnidge J, Meurer M, Schwarz S, Feßler AT, and The Biocide Susceptibility Study Group

Abstract

Every laboratory test needs validation by quality controls. For biocide susceptibility testing (BST), neither quality control (QC) strains nor QC ranges applicable to these strains are currently available. As QC strains, four well-defined laboratory reference strains ( Staphylococcus aureus ATCC ® 6538, Enterococcus hirae ATCC ® 10541, Escherichia coli ATCC ® 10536 and Pseudomonas aeruginosa ATCC ® 15442), which have been used previously for biocide efficacy testing, were selected. In an interlaboratory trial with eleven participating laboratories, BST QC ranges should be developed for the aforementioned four strains and the four biocides benzalkonium chloride, chlorhexidine, octenidine and polyhexanide. The performance of three different lots of tryptic soy broth was explored using the broth microdilution method and the data were subsequently evaluated using the RangeFinder software. As a result, QC ranges were defined for all reference strain-biocide combinations, except for P. aeruginosa ATCC ® 15442 with the two biocides chlorhexidine and polyhexanide. The development of the latter two QC ranges was not possible, due to the limited solubility of the biocides in the test range required for P. aeruginosa ATCC ® 15442. The newly developed QC ranges comprise three to five dilution steps. The establishment of QC ranges will contribute to the validation of BST in the future.

Published
2022
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