Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Molecular typing of Streptococcus suis strains isolated from diseased and healthy pigs between 1996-2016
Louise Prüfer, T. ; Rohde, Judith ; Verspohl, Jutta ; Rohde, Manfred ; Greeff, Astrid De; Willenborg, Jörg ; Valentin-Weigand, Peter - \ 2019
PLoS ONE 14 (2019)1. - ISSN 1932-6203

Streptococcus suis is an economically important pathogen of pigs as well as a zoonotic cause of human disease. Serotyping is used for further characterization of isolates; some serotypes seem to be more virulent and more widely spread than others. This study characterizes a collection of German field isolates of Streptococcus suis from pigs dating from 1996 to 2016 with respect to capsular genes (cps) specific for individual serotypes and pathotype by multiplex PCR and relates results to the clinical background of these isolates. The most prominent finding was the reduction in prevalence of serotype-2/serotype-1/2 among invasive isolates during this sampling period, which might be attributed to widely implemented autogenous vaccination programs in swine against serotype 2 in Germany. In diseased pigs (systemically ill; respiratory disease) isolates of serotype-1/serotype-14, serotype-2/serotype-1/2, serotype 3 to 5 and 7 to 9 were most frequent while in carrier isolates a greater variety of cps types was found. Serotype-1/serotype-14 seemed to be preferentially located in joints, serotype 4 and serotype 3 in the central nervous system, respectively. The virulence associated extracellular protein factor was almost exclusively associated with invasive serotype-1/serotype-14 and serotype-2/serotype-1/2 isolates. In contrast, lung isolates of serotype-2/serotype-1/2 mainly harbored the gene for muramidase-released protein. Serotype 4 and serotype 9 isolates from clinically diseased pigs most frequently carried the muramidase-released protein gene and the suilysin gene. When examined by transmission electron microscopy all but one of the isolates which were non-typable by molecular and serological methods showed various amounts of capsular material indicating potentially new serotypes among these isolates. Given the variety of cps types/serotypes detected in pigs, not only veterinarians but also medical doctors should consider other serotypes than just serotype 2 when investigating potential human cases of Streptococcus suis infection.

The effects of probiotics in pigs on host responses and microbiota composition and their putative role to prevent Escherichia colli.
Greeff, A. de; Vastenhouw, S.A. ; Cornelissen, J.B.W.J. ; Bossers, A. ; Harders, F.L. ; Rebel, J.M.J. - \ 2018
LPS challenge in jonge biggen : VDI-12: effect voerinterventie op biggen
Greeff, Astrid de; Allaart, Janneke ; Bruijn, Carlijn de; Schokker, Dirkjan ; Roubos, Petra ; Winkelman-Goedhart, Hélène ; Vastenhouw, Stéphanie ; Ruuls, Lisette ; Rebel, Johanna ; Smits, Mari - \ 2016
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1009) - 21
biggen - maatregel op voedingsgebied - adequate immuniteit - diergezondheid - lipopolysacchariden - varkenshouderij - dierhouderij - immunologie - piglets - nutritional intervention - immune competence - animal health - lipopolysaccharides - pig farming - animal husbandry - immunology
FlpS, the FNR-like protein of streptococcus suis is an essential, oxygen-sensing activator of the arginine deiminase system
Willenborg, Jörg ; Koczula, Anna ; Fulde, Marcus ; Greeff, Astrid de; Beineke, Andreas ; Eisenreich, Wolfgang ; Huber, Claudia ; Seitz, Maren ; Valentin-Weigand, Peter ; Goethe, Ralph - \ 2016
Pathogens 5 (2016)3. - ISSN 2076-0817
Arginine deiminase system - FNR-like protein - Streptococcus suis

Streptococcus (S.) suis is a zoonotic pathogen causing septicemia and meningitis in pigs and humans. During infection S. suis must metabolically adapt to extremely diverse environments of the host. CcpA and the FNR family of bacterial transcriptional regulators are important for metabolic gene regulation in various bacteria. The role of CcpA in S. suis is well defined, but the function of the FNR-like protein of S. suis, FlpS, is yet unknown. Transcriptome analyses of wild-type S. suis and a flpS mutant strain suggested that FlpS is involved in the regulation of the central carbon, arginine degradation and nucleotide metabolism. However, isotopologue profiling revealed no substantial changes in the core carbon and amino acid de novo biosynthesis. FlpS was essential for the induction of the arcABC operon of the arginine degrading pathway under aerobic and anaerobic conditions. The arcABC-inducing activity of FlpS could be associated with the level of free oxygen in the culture medium. FlpS was necessary for arcABC-dependent intracellular bacterial survival but redundant in a mice infection model. Based on these results, we propose that the core function of S. suis FlpS is the oxygen-dependent activation of the arginine deiminase system.

Simultaneous Quantification and Differentiation of Streptococcus suis Serotypes 2 and 9 by Quantitative Real-time PCR, Evaluated in Tonsillar and Nasal Samples of Pigs
Dekker, Niels ; Daemen, Ineke ; Verstappen, K.M. ; Greeff, A. de; Smith, H.E. ; Duim, Birgitta - \ 2016
Pathogens 5 (2016)3. - ISSN 2076-0817
Abstract Invasive Streptococcus suis (S. suis) infections in pigs are often associated with serotypes 2 and 9. Mucosal sites of healthy pigs can be colonized with these serotypes, often multiple serotypes per pig. To unravel the contribution of these serotypes in pathogenesis and epidemiology, simultaneous quantification of serotypes is needed. A quantitative real-time PCR (qPCR) targeting cps2J (serotypes 2 and 1/2) and cps9H (serotype 9) was evaluated with nasal and tonsillar samples from S. suis exposed pigs. qPCR specifically detected serotypes in all pig samples. The serotypes loads in pig samples estimated by qPCR showed, except for serotype 9 in tonsillar samples (correlation coefficient = 0.25), moderate to strong correlation with loads detected by culture (correlation coefficient > 0.65), and also in pigs exposed to both serotypes (correlation coefficient > 0.75). This qPCR is suitable for simultaneous differentiation and quantification of important S. suis serotypes
Supplementation of piglets with nutrient-dense complex milk replacer improves intestinal development and microbial fermentation
Greeff, A. de; Resink, J.W. ; Hees, H.M.J. van; Ruuls, L. ; Klaassen, G.J. ; Rouwers, S.M.G. ; Stockhofe-Zurwieden, N. - \ 2016
Journal of Animal Science 94 (2016)3. - ISSN 0021-8812 - p. 1012 - 1019.
Circular intestinal growth - Gene expression - Gut health - Nutrient-dense complex milk replacer - Pig

Weaning of piglets causes stress due to environmental, behavioral, and nutritional stressors and can lead to postweaning diarrhea and impaired gut development. The diet changes experienced during weaning require extensive adaptation of the digestive system. A well-developed piglet that had creep-feed experience before weaning performs better after weaning. In the current study, the effect of providing sow-fed piglets with a supplemental nutrient-dense complex milk replacer (NDM) on gut development and growth performance was studied. Litters of sows with similar parities (3.6 ± 0.8) and similar numbers of live born piglets (13.5 ± 0.3) were assigned to 1 of 2 groups: 1 group of piglets had ad libitum access to NDM from Day 2 through 21 after birth, whereas the other group was used as controls. Nutrient-dense complex milk replacer–fed piglets were shown to be significantly heavier after 21 d of supplementation compared with the control piglets. At Day 21, 3 piglets from each litter were euthanized for morphological and functional analyses of the intestinal tract. The small intestines of NDM-fed piglets had significantly higher weights (g) as well as significantly higher relative weight:length ratios (g//cm) compared with the small intestines of control piglets (P <0.05). Morphometric analysis demonstrated that villi length and numbers of goblet cells did not differ between groups. However, NDM-fed piglets had deeper crypts (P <0.001) and an increased expression of the cell-proliferation marker proliferating cell nuclear antigen in crypts (P <0.05), suggesting higher cell-proliferation rates. The gene encoding IGF- 1 showed a tendency to higher gene expression in the jejunum from NDM-fed piglets (P = 0.07) compared with the jejunum from control piglets, suggesting that IGF-1 might be involved in the regulation of cell proliferation and intestinal growth. Finally, as a result of dietary fiber in NDM, piglets showed significantly increased concentrations of metabolic fermentation products. This suggests differences in metabolic activity in the colon between treatment groups. In conclusion, providing sow-fed piglets with NDM before weaning stimulates intestinal proliferation, leading to increased circular growth. Nutrient-dense complex milk replacer supplementation might, therefore, help piglets through the transition period at weaning by increased BW and increased capacity for uptake of nutrients.

Pneumococcal colonization and invasive disease studied in a porcine model
Greeff, Astrid de; Selm, Saskia van; Buys, Herma ; Harders-Westerveen, José F. ; Tunjungputri, Rahajeng N. ; Mast, Quirijn de; Ven, Andre J. van der; Stockhofe-Zurwieden, Norbert ; Jonge, Marien I. de; Smith, Hilde E. - \ 2016
BMC Microbiology 16 (2016)1. - ISSN 1471-2180
Animal model - Colonization - Pigs - Streptococcus pneumoniae

Background: Streptococcus pneumoniae, a Gram-positive bacterium carried in the human nasopharynx, is an important human pathogen causing mild diseases such as otitis media and sinusitis as well as severe diseases including pneumonia, meningitis and sepsis. There is a strong resemblance between the anatomy, immunology and physiology of the pig and human species. Furthermore, there are striking similarities between S. suis pathogenesis in piglets and S. pneumoniae pathogenesis in humans. Therefore, we investigated the use of piglets as a model for pneumococcal colonization and invasive disease. Results: Intravenous inoculation of piglets with an invasive pneumococcal isolate led to bacteraemia during 5 days, showing clear bacterial replication in the first two days. Bacteraemia was frequently associated with fever and septic arthritis. Moreover, intranasal inoculation of piglets with a nasopharyngeal isolate led to colonization for at least six consecutive days. Conclusions: This demonstrates that central aspects of human pneumococcal infections can be modelled in piglets enabling the use of this model for studies on colonization and transmission but also on development of vaccines and host-directed therapies. Moreover this is the first example of an animal model inducing high levels of pneumococcal septic arthritis.

Invasive pneumococcal disease leads to activation and hyperreactivity of platelets
Tunjungputri, Rahajeng N. ; Jonge, Marien I. de; Greeff, Astrid de; Selm, Saskia van; Buys-Bergen, Herma ; Harders-Westerveen, Jose F. ; Stockhofe-Zurwieden, Norbert ; Urbanus, Rolf T. ; Groot, Phillip G. De; Smith, Hilde E. ; Ven, Andre J. van der; Mast, Quirijn de - \ 2016
Thrombosis Research 144 (2016). - ISSN 0049-3848 - p. 123 - 126.
Infection - Myocardial infarction - Platelet activation - Platelets - Pneumonia - Streptococcus pneumoniae

Using a novel porcine model of intravenous Streptococcus pneumoniae infection, we showed that invasive pneumococcal infections induce marked platelet activation and hyperreactivity. This may contribute to the vascular complications seen in pneumococcal infection.

Rapid detection of Streptococcus uberis in raw milk by loop-mediated isothermal amplification
Cornelissen, J.B.W.J. ; Greeff, A. De; Heuvelink, A.E. ; Swarts, M. ; Smith, H.E. ; Wal, F.J. Van der - \ 2016
Journal of Dairy Science 99 (2016)6. - ISSN 0022-0302 - p. 4270 - 4281.
Loop-mediated isothermal amplification (LAMP) - Mastitis - Raw milk - Streptococcus uberis

A loop-mediated isothermal amplification (LAMP) method to detect Streptococcus uberis in raw milk was developed and evaluated. Three genes (sodA, pauA, cpn60) were assessed for their suitability as targets in LAMP. The analytical sensitivity was 120, 120, and 12 fg per assay for the sodA, pauA, and cpn60 assays, respectively, with a detectable signal within 8 min for the highest concentration (12 ng/assay) and ∼60 min for the lowest concentrations. The LAMP assays correctly identified 7 Strep. uberis strains among a set of 83 mastitis pathogens. To enable DNA isolation from raw milk, a new method was used in which a pretreatment with a cocktail of lysing enzymes was performed before an established procedure. This method resulted in an analytical sensitivity of 48 cfu/assay for the sodA LAMP assay using raw milk spiked with Strep. uberis, corresponding to 2.4 × 104 cfu/mL milk. For raw milk samples from cows experimentally infected with Strep. uberis, results of enumeration were largely reflected by results of LAMP. Evaluation of the sodA LAMP assay with 100 raw milk field samples, of which 50 were Strep. uberis culture-negative and 50 Strep. uberis culture-positive, showed that the assay had a diagnostic sensitivity of 96.0% and a diagnostic specificity of 96.0%. In conclusion, the described LAMP assay may offer a simple alternative for convenient and sensitive detection of S. uberis in raw milk, provided a compatible rapid DNA isolation procedure is available.

Increased fat and polyunsaturated fatty acid content in sow gestation diet has no effect on gene expression in progeny during the first 7 days of life
Greeff, Astrid de; Bikker, P. ; Smit-Heinsbroek, A. ; Bruininx, E. ; Zwolschen, H. ; Fijten, H.P.D. ; Zetteler, P. ; Vastenhouw, S.A. ; Smits, M.A. ; Rebel, J.M.J. - \ 2016
Journal of Animal Physiology and Animal Nutrition 100 (2016)1. - ISSN 0931-2439 - p. 127 - 135.
The ‘developmental origins of health and disease’ hypothesis proposes not only that we are what we eat, but also that we could be what our parents ate. Here, we aimed to improve health and performance of young piglets via maternal diets based on the hypothesis that maternal nutritional interventions change metabolic programming in piglets, reflected by differential gene expression early in life. Therefore, sows were fed either a regular diet, based on barley, wheat and wheat by-products, sugar beet pulp, palm oil and oilseed meal, or a high-fat (HF) diet consisting of the regular diet supplemented with an additional amount of 3.5% soybean oil and 1% fish oil at the expense of palm oil and wheat. Performance results, physiological parameters and gene expression in liver of piglets and blood of piglets and sows at day 7 after farrowing from both diet groups were compared. The HF diet tended to enhance growth rate of the offspring in the first week of life. No significant differences in gene expression in liver tissue and blood could be detected between the two groups, neither with whole-genome microarray analysis, nor with gene specific qPCR analysis. In this study, the feeding of a high-fat diet with increased amounts of polyunsaturated fatty acid (PUFA) to gestating sows under practical farm settings did not induce significant changes in gene expression in sows and offspring.
Host-pathogen interaction at the intestinal mucosa correlates with zoonotic potential of Streptococcus suis
Ferrando, Maria Laura ; Greeff, Astrid De; Rooijen, W.J.M. Van; Stockhofe-Zurwieden, Norbert ; Nielsen, Jens ; Wichgers Schreur, P.J. ; Pannekoek, Yvonne ; Heuvelink, Annet ; Ende, Arie Van Der; Smith, Hilde ; Schultsz, Constance - \ 2015
The Journal of Infectious Diseases 212 (2015)1. - ISSN 0022-1899 - p. 95 - 105.
clonal complex - intestinal translocation - piglets. - serotype - Streptococcus suis - tight junctions - zoonotic infections

Streptococcus suis has emerged as an important cause of bacterial meningitis in adults. The ingestion of undercooked pork is a risk factor for human S. suis serotype 2 (SS2) infection. Here we provide experimental evidence indicating that the gastrointestinal tract is an entry site of SS2 infection. Methods. We developed a noninvasive in vivo model to study oral SS2 infection in piglets.We compared in vitro interaction of S. suis with human and porcine intestinal epithelial cells (IEC). Results. Two out of 15 piglets showed clinical symptoms compatible with S. suis infection 24-48 hours after ingestion of SS2. SS2 was detected in mesenteric lymph nodes of 40% of challenged piglets. SS2 strains isolated from patients showed significantly higher adhesion to human IEC compared to invasive strains isolated from pigs. In contrast, invasive SS9 strains showed significantly higher adhesion to porcine IEC. Translocation across human IEC, which occurred predominately via a paracellular route, was significantly associated with clonal complex 1, the predominant zoonotic genotype. Adhesion and translocation were dependent on capsular polysaccharide production. Conclusions. SS2 should be considered a food-borne pathogen. S. suis interaction with human and pig IEC correlates with S. suis serotype and genotype, which can explain the zoonotic potential of SS2.

Effect of maternal antibiotic intervention in sows on gut development and microbiota in offspring : report of Feed4Foodure, VDI-2: 2013/2014
Greeff, A. de; Schokker, D. ; Roubos, P. ; Ramaekers, P. ; Peet-Schwering, C.M.C. van der; Bikker, P. ; Vastenhouw, S.A. ; Bree, F.M. de; Bossers, A. ; Harders, F.L. ; Smits, M.A. ; Rebel, J.M.J. - \ 2015
Wageningen : Wageningen UR Livestock Research (Livestock Research report 892) - 48
zeugen - antibiotica - microbiële besmetting - biggen - maatregel op voedingsgebied - varkenshouderij - diergezondheid - dierenwelzijn - veehouderij - sows - antibiotics - microbial contamination - piglets - nutritional intervention - pig farming - animal health - animal welfare - livestock farming
A significant contribution to microbial colonization of piglets comes from the sow: via vertical transmission of vaginal flora during birth and transmission of mucosal immune memory and flora by feaces, colostrum and milk. In this study we determine the effect of an maternal nutritional intervention with an antibiotic on early microbial colonization of piglets. We used antibiotic treatment as a harsh intervention to investigate the hypothesis that the microbial composition in sows, may have an effect on the early microbial colonization of piglets.
Latest developments on Streptococcus suis: an emerging zoonotic pathogen: part 1
Segura, M. ; Zheng, H. ; Greeff, A. de; Gao, G.F. ; Grenier, D. ; Jiang, Y. ; Chengping, L. ; Maskell, D. ; Oishi, K. ; Okura, M. ; Osawa, R. ; Schultsz, C. ; Schwerk, C. ; Sekizaki, T. ; Smith, H. ; Srimanote, P. ; Takamatsu, D. ; Tang, J. ; Tenenbaum, T. ; Tharavichitkul, P. ; Hoa, N.T. ; Valentin-Weigand, P. ; Wells, J.M. ; Wertheim, H. ; Zhu, B. ; Xu, J. ; Gottschalk, M. - \ 2014
Future Microbiology 9 (2014)4. - ISSN 1746-0913 - p. 441 - 444.
serotype-2 - thailand - infection - diversity
The first international workshop on Streptococcus suis, which is an important swine pathogen and emerging zoonotic agent, took place in Beijing, jointly organized by the Faculty of Veterinary Medicine, University of Montreal, Canada and the National Institute for Communicable Disease Control and Prevention, China CDC. The aim of the meeting was to gather together, for the first time, more than 80 researchers working on S. suis, from countries including China, Canada, Japan, The Netherlands, Germany, Thailand, the UK and Vietnam. This article, the first of a two-part report on this First International Workshop, reviews current aspects of the epidemiology and population genomics of S. suis, covers public health concerns and discusses questions about S. suis serotyping and molecular diagnostics.
A naturally occurring nucleotide polymorphism in the orf2/folc promoter is associated with Streptococcus suis virulence
Greeff, A. de; Buys, H. ; Wells, J.M. ; Smith, H.E. - \ 2014
BMC Microbiology 14 (2014)1. - ISSN 1471-2180
germ-free pigs - serotype-2 - strains - identification - cytokine - pathogen - suilysin - release - type-2 - cells
Streptococcus suis is a major problem in the swine industry causing meningitis, arthritis and pericarditis in piglets. Pathogenesis of S. suis is poorly understood. We previously showed that introduction of a 3 kb genomic fragment from virulent serotype 2 strain 10 into a weakly virulent serotype 2 strain S735, generated a hypervirulent isolate. The 3 kb genomic fragment contained two complete open reading frames (ORF) in an operon-structure of which one ORF showed similarity to folylpolyglutamate synthetase, whereas the function of the second ORF could not be predicted based on database searches for protein similarity.
Host response and microbiota composition after Lactobacillus administration: pig as model for human
Greeff, A. de; Schokker, D. ; Bree, F.M. de; Bossers, A. ; Vastenhouw, S.A. ; Harders, F.L. ; Kleerebezem, M. ; Wells, J.M. ; Smits, M.A. ; Rebel, J.M.J. - \ 2014
In: Book of abstracts of the 65th Annual Meeting of the European Association of Animal Science. - Wageningen Academic Publishers - ISBN 9789086862481 - p. 297 - 297.
Effects of maternal nutrition on immune competence and microbiota composition of piglets
Greeff, A. de; Vastenhouw, S.A. ; Bikker, P. ; Bossers, A. ; Bree, F.M. de; Schokker, D. ; Roubos-van den Hil, P.J. ; Ramaekers, P. ; Smits, M.A. ; Rebel, J.M.J. - \ 2014
In: Book of abstracts of the 65th Annual Meeting of the European Association for Animal Production. - Wageningen Academic Publishers - ISBN 9789086862481 - p. 125 - 125.
Control of Competence for DNA Transformation in Streptococcus suis by Genetically Transferable Pherotypes
Zaccaria, E. ; Baarlen, P. van; Greeff, A. de; Morrison, D.A. ; Smith, H. ; Wells, J.M. - \ 2014
PLoS ONE 9 (2014)6. - ISSN 1932-6203 - 8 p.
horizontal gene-transfer - bacterial transformation - haemophilus-influenzae - peptide pheromone - pneumoniae - thermophilus - activation - expression - regulator - system
Here we show that S. suis, a major bacterial pathogen of pigs and emerging pathogen in humans responds to a peptide pheromone by developing competence for DNA transformation. This species does not fall within any of the phylogenetic clusters of streptococci previously shown to regulate competence via peptide pheromones suggesting that more species of streptococci may be naturally competent. Induction of competence was dependent on ComX, a sigma factor that controls the streptococcal late competence regulon, extracellular addition of a comX-inducing peptide (XIP), and ComR, a regulator of comX. XIP was identified as an N-terminally truncated variant of ComS. Different comS alleles are present among strains of S. suis. These comS alleles are not functionally equivalent and appear to operate in conjuction with a cognate ComR to regulate comX through a conserved comR-box promoter. We demonstrate that these ‘pherotypes’ can be genetically transferred between strains, suggesting that similar approaches might be used to control competence induction in other lactic acid bacteria that lack ComR/ComS homologues but possess comX and the late competence regulon. The approaches described in this paper to identify and optimize peptide-induced competence may also assist other researchers wishing to identify natural competence in other bacteria. Harnessing natural competence is expected to accelerate genetic research on this and other important streptococcal pathogens and to allow high-throughput mutation approaches to be implemented, opening up new avenues for research.
The Ccpa regulon of Streptococcus suis reveals novel insights into the regulation of the streptococcal central carbon metabolism by binding of CcpA to two distinct binding motifs.
Willenborg, J. ; Greeff, A. de; Jarek, M. ; Valentin-Weigand, P. ; Goethe, R. - \ 2014
Molecular Microbiology 92 (2014)1. - ISSN 0950-382X - p. 61 - 83.
sugar phosphotransferase system - bacillus-subtilis - catabolite repression - virulence - bacteria - phosphoenolpyruvate - expression - pathogen - hpr - phosphocarrier
Streptococcus suis (S.¿suis) is a neglected zoonotic streptococcus causing fatal diseases in humans and in pigs. The transcriptional regulator CcpA (catabolite control protein A) is involved in the metabolic adaptation to different carbohydrate sources and virulence of S.¿suis and other pathogenic streptococci. In this study, we determined the DNA binding characteristics of CcpA and identified the CcpA regulon during growth of S.¿suis. Electrophoretic mobility shift analyses showed promiscuous DNA binding of CcpA to cognate cre sites in vitro. In contrast, sequencing of immunoprecipitated chromatin revealed two specific consensus motifs, a pseudo-palindromic cre motif (WWGAAARCGYTTTCWW) and a novel cre2 motif (TTTTYHWDHHWWTTTY), within the regulatory elements of the genes directly controlled by CcpA. Via these elements CcpA regulates expression of genes involved in carbohydrate uptake and conversion, and in addition in important metabolic pathways of the central carbon metabolism, like glycolysis, mixed-acid fermentation, and the fragmentary TCA cycle. Furthermore, our analyses provide evidence that CcpA regulates the genes of the central carbon metabolism by binding either the pseudo-palindromic cre motif or the cre2 motif in a HPr(Ser)~P independent conformation.
Latest developments on Streptococcus suis: an emerging zoonotic pathogen: part 2
Segura, M. ; Zheng, H. ; Greeff, A. de; Gao, G.F. ; Gremier, D. ; Jiang, Y. ; Chengping, L. ; Maskell, D. ; Oishi, K. ; Okura, M. ; Osawa, R. ; Schultsz, C. ; Schwerk, C. ; Sekizaki, T. ; Smith, H. ; Srimanote, P. ; Takamatsu, D. ; Tang, J. ; Tenenbaum, T. ; Tharavichitkul, P. ; Hoa, N.T. ; Valentin-Weigand, P. ; Wells, J.M. ; Wertheim, H. ; Zhu, B. ; Xu, J. ; Gottschalk, M. - \ 2014
Future Microbiology 9 (2014)5. - ISSN 1746-0913 - p. 587 - 591.
cerebrospinal fluid barrier - plexus epithelial-cells - in-vitro - bacterial interactions - swine pathogen - serotype-2 - infection - diversity - virulence - release
This second and final chapter of the report on the First International Workshop on Streptococcus suis follows on from Part 1, published in the April 2014, volume 9, issue 4 of Future Microbiology. S. suis is a swine pathogen and a zoonotic agent afflicting people in close contact with infected pigs or pork meat. Although sporadic cases of human infections had been reported worldwide, deadly S. suis outbreaks emerged in Asia. The severity of the disease underscores the lack of knowledge on the virulence and zoonotic evolution of this human-infecting agent. The pathogenesis of the infection, interactions with host cells and new avenues for treatments were among the topics discussed during the First International Workshop on S. suis (China 2013).
Carbohydrate Availability Regulates Virulence Gene Expression in Streptococcus suis
Ferrando, M.L. ; Baarlen, P. van; Orrù, G. ; Piga, R. ; Bongers, R.S. ; Wels, M. ; Greeff, A. de; Smith, H. ; Wells, J.M. - \ 2014
PLoS ONE 9 (2014)3. - ISSN 1932-6203 - 16 p.
group-a streptococcus - fibronectin-binding protein - bacillus-subtilis - glycogen-metabolism - escherichia-coli - epithelial-cells - mouse intestine - molecular characterization - hyaluronan concentration - catabolite repression
Streptococcus suis is a major bacterial pathogen of young pigs causing worldwide economic problems for the pig industry. S. suis is also an emerging pathogen of humans. Colonization of porcine oropharynx by S. suis is considered to be a high risk factor for invasive disease. In the oropharyngeal cavity, where glucose is rapidly absorbed but dietary a-glucans persist, there is a profound effect of carbohydrate availability on the expression of virulence genes. Nineteen predicted or confirmed S. suis virulence genes that promote adhesion to and invasion of epithelial cells were expressed at higher levels when S. suis was supplied with the a-glucan starch/pullulan compared to glucose as the single carbon source. Additionally the production of suilysin, a toxin that damages epithelial cells, was increased more than ten-fold when glucose levels were low and S. suis was growing on pullulan. Based on biochemical, bioinformatics and in vitro and in vivo gene expression studies, we developed a biological model that postulates the effect of carbon catabolite repression on expression of virulence genes in the mucosa, organs and blood. This research increases our understanding of S. suis virulence mechanisms and has important implications for the design of future control strategies including the development of anti-infective strategies by modulating animal feed composition
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