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inactivation of the soda gene of streptococcus suis type 2 encoding superoxide dismutase leads to reduced virulence to mice.superoxide dismutase (sod) is a virulence factor of certain pathogenic bacteria by diminishing the effect of oxidative burst of phagocytic cells. earlier reports indicated the presence of manganese-cofactored sod in streptococcus suis type 2 (ss2). however, the biological role of sod and its coding sequence in ss2 has not yet been characterized. the ssu1356-orf of a clinical ss2 strain zj081101 encodes a protein of 201 amino acids with 81-88% identity to soda of other streptococcus spp. a sod de ...201222424868
identification of candidate susceptibility and resistance genes of mice infected with streptococcus suis type 2.streptococcus suis type 2 (ss2) is an important swine pathogen and zoonosis agent. a/j mice are significantly more susceptible than c57bl/6 (b6) mice to ss2 infection, but the genetic basis is largely unknown. here, alterations in gene expression in ss2 (strain ha9801)-infected mice were identified using illumina mouse beadchips. microarray analysis revealed 3,692 genes differentially expressed in peritoneal macrophages between a/j and b6 mice due to ss2 infection. between ss2-infected a/j and c ...201222384161
severe cochlear inflammation and vestibular syndrome in an experimental model of streptococcus suis infection in mice.hearing impairment is a common and frequently permanent sequel of streptococcus suis meningitis in humans. nevertheless, mechanisms underlying the development of cochlear damage have not been addressed so far. in the present work, we characterized a mouse model of suppurative labyrinthitis and meningitis induced by a systemic infection with s. suis and studied the impact of the injected bacterial dosage on the progression of such inflammatory events. we observed that high infection doses of bact ...201222382820
population-based study of streptococcus suis infection in humans in phayao province in northern thailand.streptococcus suis infection in humans has received increasing worldwide recognition.201222363601
fisher scientific award lecture - the capsular polysaccharides of group b streptococcus and streptococcus suis differently modulate bacterial interactions with dendritic cells.infections with encapsulated bacteria cause serious clinical problems. besides being poorly immunogenic, the bacterial capsular polysaccharide (cps) cloaks antigenic proteins, allowing bacterial evasion of the host immune system. despite the clinical significance of bacterial cps and its suggested role in the pathogenesis of the infection, the mechanisms underlying innate and, critically, adaptive immune responses to encapsulated bacteria have not been fully elucidated. as such, we became intere ...201222356626
virulence factors involved in the pathogenesis of the infection caused by the swine pathogen and zoonotic agent streptococcus suis.streptococcus suis is a major swine pathogen responsible for important economic losses to the swine industry worldwide. it is also an emerging zoonotic agent of meningitis and streptococcal toxic shock-like syndrome. since the recent recognition of the high prevalence of s. suis human disease in southeast and east asia, the interest of the scientific community in this pathogen has significantly increased. in the last few years, as a direct consequence of these intensified research efforts, large ...201222324994
[expression, purification and protective antigen analysis of cell wall protein mrp of streptococcus suis type 2].to amplify the mrp gene of streptococcus suis type 2 05zyh33, express it in e.coli bl21 in order to acquire high purity recombinant protein mrp, then evaluate the protective antigen of recombinant protein mrp.201222304764
streptococcus suis ii immunoassay based on thorny gold nanoparticles and surface enhanced raman scattering.an immunoassay based on surface enhanced raman scattering (sers) spectroscopy was developed to detect muramidase released protein (mrp) antibody against streptococcus suis ii (ss2) utilizing thorny gold nanoparticles (taunps) as sers substrates. initially, taunps with multi-branches were prepared by the seed-mediated growth method in the absence of templates and surfactants, facilitating p-mercaptobenzoic acid (pmba) conjugation covalently onto the taunps through s-au bonds. the obtained immuno- ...201222282767
streptococcus suis, an emerging drug-resistant animal and human pathogen.streptococcus suis, a major porcine pathogen, has been receiving growing attention not only for its role in severe and increasingly reported infections in humans, but also for its involvement in drug resistance. recent studies and the analysis of sequenced genomes have been providing important insights into the s. suis resistome, and have resulted in the identification of resistance determinants for tetracyclines, macrolides, aminoglycosides, chloramphenicol, antifolate drugs, streptothricin, an ...201122275909
polar invasion and translocation of neisseria meningitidis and streptococcus suis in a novel human model of the blood-cerebrospinal fluid barrier.acute bacterial meningitis is a life-threatening disease in humans. discussed as entry sites for pathogens into the brain are the blood-brain and the blood-cerebrospinal fluid barrier (bcsfb). although human brain microvascular endothelial cells (hbmec) constitute a well established human in vitro model for the blood-brain barrier, until now no reliable human system presenting the bcsfb has been developed. here, we describe for the first time a functional human bcsfb model based on human choroid ...201222253884
characterization and functional analysis of atl, a novel gene encoding autolysin in streptococcus suis.streptococcus suis serotype 2 (s. suis 2) is an important swine and human pathogen responsible for septicemia and meningitis. a novel gene, designated atl and encoding a major autolysin of s. suis 2 virulent strain ha9801, was identified and characterized in this study. the atl protein contains 1,025 amino acids with a predicted molecular mass of 113 kda and has a conserved n-acetylmuramoyl-l-alanine amidase domain. recombinant atl was expressed in escherichia coli, and its bacteriolytic and fib ...201222228730
homologous whole bacterin vaccination is not able to reduce streptococcus suis serotype 9 strain 7997 transmission among pigs or colonization.streptococcus suis (s. suis) is an important porcine pathogen worldwide, and antibiotics are often applied to treat or prevent clinical signs. vaccination could be an alternative measure to reduce the abundant use of antimicrobials. the aim of this study was to determine the effect of vaccination with homologues whole bacterin vaccine containing s. suis serotype 9 strain 7997 on transmission of this serotype among pigs and on mucosal colonization. caesarean derived, colostrum deprived pigs (n=50 ...201122210137
functional definition of luxs, an autoinducer-2 (ai-2) synthase and its role in full virulence of streptococcus suis serotype 2.quorum sensing is a widespread chemical communication in response to fluctuation of bacterial population density, and has been implicated into bacterial biofilm formation and regulation of expression of virulence factors. the luxs gene product, s-ribosylhomocysteinase, catalizes the last committed step in biosynthetic pathway of autoinducer 2 (ai-2), a signaling molecule for inter-species quorum sensing. we found a luxs homologue in 05zyh33, an epidemic strain of streptococcus suis serotype 2 (s ...201122203565
streptococcus suis: a potential risk factor for salivary gland tumors. 201122180174
lineage and virulence of streptococcus suis serotype 2 isolates from north america.we performed multilocus sequence typing of 64 north american streptococcus suis serotype 2 porcine isolates. strains were sequence type (st) 28 (51%), st25 (44%), and st1 (5%). we identified nonrandom associations between sts and expression of the virulence markers suilysin (sly), muramidase-relased protein (mrp), and extracellular factor (ef). expression of pili encoded by the srtf and srtg pilus clusters was also nonrandomly associated with sts. st1 strains were sly+ ef+ mrp+ srtf pilus+ srtg ...201122172538
Bacterial pathogens associated with lung lesions in slaughter pigs from 125 herds.Relationships between macroscopic lesions and Polymerase Chain Reaction (PCR) detection of Mycoplasma hyopneumoniae (Mhp), Pasteurella multocida (Pm), Actinobacillus pleuropneumoniae (App), Haemophilus parasuis (Hps) and Streptococcus suis (Ssuis) of the lungs of 3731 slaughter pigs from 125 herds were assessed in France. Pneumonia and pleuritis were the most frequent lesions (69.3% and 15% of the lungs, respectively). Mhp, Pm, App, Ssuis and Hps were detected in 69.3%, 36.9%, 20.7%, 6.4% and 0. ...201122133708
streptococcus suis capsular polysaccharide inhibits phagocytosis through destabilization of lipid microdomains and prevents lactosylceramide-dependent recognition.streptococcus suis type 2 is a major swine pathogen and a zoonotic agent, causing meningitis both in swine and humans. s. suis infects the host through the respiratory route, reaches the bloodstream and persists until breaching into the central nervous system. the capsular polysaccharide (cps) of s. suis type 2 is considered a key virulence factor of the bacteria. though cps allows s. suis to adhere to the membrane of cells of the immune system, it provides protection against phagocytosis. in fa ...201122124659
characterization of the streptococcus suis xers recombinase and its unconventional cleavage of the difsl site.xerc and xerd are members of the tyrosine recombinase family and mediate site-specific recombination that contributes to the stability of circular chromosomes in bacteria by resolving plasmid multimers and chromosome dimers to monomers prior to cell division. homologues of xerc/xerd genes have been found in many bacteria, and in the lactococci and streptococci, a single recombinase called xers can perform the functions of xerc and xerd. the xers gene of streptococcus suis was cloned, overexpress ...201122092814
genetic analysis of the capsular polysaccharide synthesis locus in 15 streptococcus suis serotypes.the capsular polysaccharide (cps) synthesis locus of 13 streptococcus suis serotypes (serotype 1, 3, 4, 5, 7, 8, 9, 10, 14, 19, 23, 25 and 1/2) was sequenced and compared with that of serotype 2 and 16. the cps synthesis locus of these 15 serotypes falls into two genetic groups. the locus is located on the chromosome between orfz and aroa. all the translated proteins in the cps synthesis locus were clustered into 127 homology groups using the tribemcl algorithm. the general organization of the l ...201122092812
Genetic and virulence characterization of Streptococcus suis type 2 isolates from swine in the provinces of Zhejiang and Henan, China.This study was aimed to examine the genetic characteristics of 44 Streptococcus suis type 2 (SS2) isolates and the virulence attributes of 23 representative isolates. Multilocus sequence typing revealed five sequence types (ST1, ST7, ST28, ST86, and ST162) with 19 isolates assigned to ST7 (43.2%), 14 to ST1 (31.8%), and 9 to ST28 (20.5%). PCR typing of the pilus gene clusters classified the isolates into three types: A (72.7%), B (22.7%), and N (4.5%). All isolates of pilus types A and N were as ...201122083785
the role of toll-like receptors in the pathogenesis of streptococcus suis.streptococcus suis is an important agent of swine and human meningitis. sequence type (st) 7 emerged in china and was responsible for the human epidemic caused by s. suis in 2005. the virulence of s. suis st7 is greater than the wild type pathogenic s. suis, st1; however, the mechanisms for this increased pathogenicity are unknown. the aim of this study was to determine the role of different toll-like receptors (tlrs) involved in regulating the host response to the s. suis infection and to specu ...201122055206
comparative genomic analysis of streptococcus suis reveals significant genomic diversity among different serotypes.streptococcus suis (s. suis) is a major swine pathogen and an emerging zoonotic agent. serotypes 1, 2, 3, 7, 9, 14 and 1/2 are the most prevalent serotypes of this pathogen. however, almost all studies were carried out on serotype 2 strains. therefore, characterization of genomic features of other serotypes will be required to better understand their virulence potential and phylogenetic relationships among different serotypes.201122026465
microbial ecology of swine farms and prrs vaccine vaccination strategies.the present study investigated the microbial ecology and vaccination strategies against porcine reproductive and respiratory syndrome (prrs) in field condition. four representative farms with a history of prrs were included in this study. over the almost 3-year period, the average detection rate was 68.9%, making prrsv the first most frequently detected virus, followed by porcine circovirus type 2 (pcv2) (64.2%), pseudorabies virus (prv) (11.03%) and classical swine fever virus (csfv) (4.41%). s ...201122014373
Application of a bacteriophage lysin to disrupt biofilms formed by the animal pathogen Streptococcus suis.Bacterial biofilms are crucial to the pathogenesis of many important infections and are difficult to eradicate. Streptococcus suis is an important pathogen of pigs, and here the biofilm-forming ability of 32 strains of this species was determined. Significant biofilms were completely formed by 10 of the strains after 60 h of incubation, with exopolysaccharide production in the biofilm significantly higher than that in the corresponding planktonic cultures. S. suis strain SS2-4 formed a dense bio ...201121984241
Comparative genomics study of multi-drug-resistance mechanisms in the antibiotic-resistant Streptococcus suis R61 strain.Streptococcus suis infections are a serious problem for both humans and pigs worldwide. The emergence and increasing prevalence of antibiotic-resistant S. suis strains pose significant clinical and societal challenges.201121966396
Large-scale identification of bacteria-host crosstalk by affinity chromatography: capturing the interactions of Streptococcus suis proteins with host cells.Protein-protein interactions between bacteria and their hosts are responsible for all types of infection processes. The investigation of the bacteria-host crosstalk can provide a comprehensive understanding of the pathogenesis of bacterial disease. Despite scattered efforts in this field, a systematic identification of interactions between host and bacterial proteins remains unavailable. Here, we develop ACSP (affinity chromatography-based surface proteomics), which combines affinity chromatogra ...201121942651
Fluoroquinolone efflux in Streptococcus suis is mediated by SatAB and not by SmrA.Streptococcus suis is an emerging zoonotic pathogen. With the lack of an effective vaccine, antibiotics remain the main tool to fight infections caused by this pathogen. We have previously observed a reserpine-sensitive fluoroquinolone (FQ) efflux phenotype in this species. Here, SatAB and SmrA, two pumps belonging to the ATP binding cassette (ABC) and the major facilitator superfamily (MFS), respectively, have been analyzed in the fluoroquinolone-resistant clinical isolate BB1013. Genes encodin ...201121930876
the novel virulence-related gene stp of streptococcus suis serotype 9 strain contributes to a significant reduction in mouse mortality.streptococcus suis is an important swine pathogen responsible for a diverse range of diseases. s. suis serotype 2 (ss2) and s. suis serotype 9 (ss9) are the prevalent serotypes in diseased chinese pigs. little is known about ss9 virulence factors. two strains, gz0565 and sh040917, were isolated from a diseased pig and a healthy pig, respectively. suppression subtractive hybridization (ssh) was used to identify ss9 virulence genes associated with pathogenicity. we identified 30 gene fragments uni ...201121924346
immunoproteomic assay of secreted proteins of streptococcus suis serotype 9 with convalescent sera from pigs.streptococcus suis is an important pathogen of pigs. in china, in addition to s. suis serotype 2, s. suis serotype 9 (ss9) is also a prevalent serotype. there is no vaccine available for ss9. an immunoproteome-based approach was developed to identify ss9 immunogenic proteins for vaccine development. secreted proteins extracted from ss9 strain gz0565 were screened by two-dimensional western blotting using convalescent sera from pigs. protein spots were excised from preparative gels and were ident ...201121909833
identification of a novel streptococcal adhesin p (sadp) protein recognizing galactosyl-α1-4-galactose-containing glycoconjugates: convergent evolution of bacterial pathogens to binding of the same host receptor.bacterial adhesion is often a prerequisite for infection, and host cell surface carbohydrates play a major role as adhesion receptors. streptococci are a leading cause of infectious diseases. however, only few carbohydrate-specific streptococcal adhesins are known. streptococcus suis is an important pig pathogen and a zoonotic agent causing meningitis in pigs and humans. in this study, we have identified an adhesin that mediates the binding of s. suis to galactosyl-α1-4-galactose (galα1-4gal)-co ...201121908601
sepsis and spontaneous bacterial peritonitis in thailand. 201121890062
critical role for streptococcus suis cell wall modifications and suilysin in resistance to complement-dependent killing by dendritic cells.streptococcus suis is an emerging zoonotic agent of septicemia and meningitis. knowledge on host immune responses toward s. suis and strategies used by this pathogen for subversion of these responses is scarce. here, s. suis modulation of dendritic cell (dc) functions were assessed for the first time. using s. suis knockout mutants in capsular polysaccharide (cps) expression, it was shown that cps blocks dc phagocytosis and impairs cytokine release by hindering cell wall components. mutants impa ...201121849289
sspep contributes to the virulence of streptococcus suis.streptococcus suis serotype 2 (ss2) is a zoonotic pathogen responsible for a spectrum of disease in pigs and that can be transmitted to humans with fatal consequences. despite the socioeconomic importance of this infection, the pathogenesis of ss2 is poorly understood. the protein sspep (05ssu0153) has been characterized as an extracellular protein. a deletion mutant of the gene encoding sspep showed significantly decreased virulence in the pig infection model. three groups challenged with diffe ...201121839825
lgt processing is an essential step in streptococcus suis lipoprotein mediated innate immune activation.background: streptococcus suis causes invasive infections in pigs and occasionally in humans. the host innate immune system plays a major role in counteracting s. suis infections. the main components of s. suis able to activate the innate immune system likely include cell wall constituents that may be released during growth or after cell wall integrity loss, however characterization of these components is still limited. methology/principal findings: a concentrated very potent innate immunity act ...201121811583
troa of streptococcus suis is required for manganese acquisition and full virulence.streptococcus suis causes infections in pigs and occasionally in humans resulting in manifestations as meningitis, sepsis, arthritis and septic shock. for survival within the host, s. suis requires numerous nutrients including trace metals. little is known about the specific proteins involved in metal scavenging in s. suis. in this study we evaluated the role of the putative high affinity metal binding lipoprotein troa in metal acquisition and virulence. a mutant strain deficient in the expressi ...201121784944
streptococcus suis meningitis with bilateral sensorineural hearing loss.streptococcus suis infection is an emerging zoonosis in asia. the most common disease manifestation is meningitis, which is often associated with hearing loss and cochleovestibular signs. s. suis infection in humans mainly occurs among risk groups that have frequent exposure to pigs or raw pork. here, we report a case of s. suis meningitis in a 67-yr-old pig carcass handler, who presented with dizziness and sensorineural hearing loss followed by headaches. gram-positive diplococci were isolated ...201121779197
loss of capsule among streptococcus suis isolates from porcine endocarditis and its biological significance.streptococcus suis, particularly serotype 2, is a pathogen of both pigs and humans associated with a wide range of diseases, including meningitis, septicemia and endocarditis. among the genes in the capsular polysaccharide biosynthesis (cps) locus, cps2j exists only in the serotype 2 and 1/2 strains; therefore, cps2j-positive strains are suspected to have capsules of serotype 2 or 1/2. coagglutination using anti-serotype 1 and anti-serotype 2 sera and/or transmission electron microscopy analysis ...201121778266
real-time pcr for detection of streptococcus suis serotype 2 in cerebrospinal fluid of human patients with meningitis.streptococcus suis serotype 2 is an emerging zoonotic pathogen and is the main cause of acute bacterial meningitis in adult patients in vietnam. we developed an internally controlled real-time pcr for detection of s. suis serotype 2 in cerebrospinal fluid (csf) samples targeted at the cps2j gene. sensitivity and specificity in culture-confirmed clinical samples were 100%. the pcr detected s. suis serotype 2 infection in 101 of 238 (42.4%) prospectively collected csf samples, of which 55 (23%) we ...201121767702
evaluation of the immunogenicity and the protective efficacy of a novel identified immunogenic protein, sspepo, of streptococcus suis serotype 2.streptococcus suis serotype 2 (s. suis 2) is an important porcine and human pathogen. some proteins secreted by s. suis 2 are thought to play important roles in the pathogenesis of this organism and in its induced immune response. sspepo has been previously identified as a secretary immunogenic protein using immunoproteomic techniques. in this study, we confirmed that the sequence of this protein is highly conserved in s. suis 2 and compared it with its homologues in other pathogens. to test the ...201121767591
Amoeba Host Model for Evaluation of Streptococcus suis Virulence.The Gram-positive bacterium Streptococcus suis is a major swine pathogen worldwide that causes meningitis, septicemia, and endocarditis. In this study, we demonstrate that the amoeba Dictyostelium discoideum can be a relevant alternative system to study the virulence of S. suis.201121742906
genetic diversity of streptococcus suis isolates as determined by comparative genome hybridization.streptococcus suis is a zoonotic pathogen that causes infections in young piglets. s. suis is a heterogeneous species. thirty-three different capsular serotypes have been described, that differ in virulence between as well as within serotypes.201121736719
microbiological identification and analysis of swine tonsils collected from carcasses at slaughter.the primary objective of this 7-month study was to determine the prevalence of porcine pathogens of the tonsil of the soft palate of swine at slaughter. additional objectives were to determine if sampling the carcasses of normal or abnormal hogs provided different microbiological profiles and if the slaughter plant provides a feasible sampling frame and environment for detecting and monitoring important pathogens in tonsils that have health implications for both swine and humans. a total of 395 ...201121731180
[expression, purification and activity assay of streptococcus suis serotype 2 cell wall protein ssu1664.]aim: to amplify the ssu1664 gene from streptococcus suis serotype 2 strain 05zy, to express the gene in e.coli, and to evaluate the activities of the recombinant protein. methods: ssu1664 gene was amplified by pcr using primers according to 05zy genome sequences and cloned into the expression vector. the recombinant protein was purified by affinity chromatography and its immunogen activities were tested by western blot and elisa. results: ssu1664 gene could solublely express in e.coli bl21(de3). ...201121722528
a novel "open-form" structure of sortasec from streptococcus suis. 201121721048
the cps locus of streptococcus suis serotype 16: development of a serotype-specific pcr assay.streptococcus suis serotype 16 can infect pigs and humans. we describe the identification and the characterization of the capsular polysaccharides synthesis locus of s. suis serotype 16. using pcr primers flanking the capsular polysaccharides synthesis locus, a 30,101-bp fragment was amplified. twenty-nine open reading frames related to transcriptional regulation, glycosyl transfer, oligosaccharide repeat unit polymerization, polysaccharide transport, sialic acid synthesis and modification were ...201121715110
pre-absorbed immunoproteomics: a novel method for the detection of streptococcus suis surface proteins.streptococcus suis serotype 2 (ss2) is a zoonotic pathogen that can cause infections in pigs and humans. bacterial surface proteins are often investigated as potential vaccine candidates and biomarkers of virulence. in this study, a novel method for identifying bacterial surface proteins is presented, which combines immunoproteomic and immunoserologic techniques. critical to the success of this new method is an improved procedure for generating two-dimensional electrophoresis gel profiles of s. ...201121713002
in vitro transcriptome analysis of porcine choroid plexus epithelial cells in response to streptococcus suis: release of pro-inflammatory cytokines and chemokines.the gram-positive zoonotic bacterium streptococcus suis (s. suis) is responsible for a wide range of diseases including meningitis in pigs and humans. the blood-cerebrospinal fluid (csf) barrier is constituted by the epithelial cells of the choroid plexus, which execute barrier function also after bacteria have entered the central nervous system (cns). we show that the bacterial capsule, a major virulence factor, strongly attenuates adhesion of s. suis to the apical side of porcine choroid plexu ...201121683799
role of a type iv-like secretion system of streptococcus suis 2 in the development of streptococcal toxic shock syndrome.streptococcus suis serotype 2 (s. suis 2) has evolved into a highly invasive pathogen that was found to be the cause of 2 large-scale outbreaks of streptococcus toxic shock syndrome (stss) in china. however, the mechanism of action of this non-group a streptococcal (gas) s. suis-caused stss is still unknown. previously, we identified a unique pathogenicity island (pai) designated 89k that is specific to the stss-causing epidemic strains of s. suis 2. in this study, we further report a functional ...201121673039
a large scale comparative genomic analysis reveals insertion sites for newly acquired genomic islands in bacterial genomes.abstract:201121672261
characterization of porcine dendritic cell response to streptococcus suis.abstract: streptococcus suis is a major swine pathogen and important zoonotic agent causing mainly septicemia and meningitis. however, the mechanisms involved in host innate and adaptive immune responses toward s. suis as well as the mechanisms used by s. suis to subvert these responses are unknown. here, and for the first time, the ability of s. suis to interact with bone marrow-derived swine dendritic cells (dcs) was evaluated. in addition, the role of s. suis capsular polysaccharide in modula ...201121635729
decreased mortality of weaned pigs with streptococcus suis with the use of in-water potassium penicillin g.this study evaluated the efficacy of potassium penicillin g in drinking water of weaned pigs to reduce mortality and spread of infection caused by streptococcus suis. a total of 896 18-day-old weaned pigs were randomly assigned to either treatment with potassium penicillin g in-water (treated), or no treatment (control). the outcomes analyzed were total mortality, mortality due to s. suis, and overall counts of s. suis colonies. the risk of mortality due to s. suis and total mortality were signi ...201121629419
neua o-acetylesterase activity is specific for cmp-activated o-acetyl sialic acid in streptococcus suis serotype 2.several bacteria causing meningitis, such as escherichia coli k1, streptococcus suis, neisseria meningitidis, and group b streptococci (gbs), produce sialic acid (neu5ac)-containing capsular polysaccharide (cps). biosynthesis of the neu5ac-containing cps requires cmp-neu5ac as substrate, which is synthesized by cmp-neu5ac synthetase from ctp and neu5ac. in e. coli or gbs, the neua protein encoded by the neua gene has been known encoding a bifunctional enzyme that possesses both cmp-neu5ac synthe ...201121624352
functional analysis of luxs in streptococcus suis reveals a key role in biofilm formation and virulence.streptococcus suis (ss) is an important pathogen of pigs, responsible for diverse diseases in swine and human. luxs has been reported to play critical roles in both regulating various behaviors and interspecies quorum sensing in a large spectrum of bacteria. in this study, the luxs deletion mutant of ss was constructed using homologous recombination and its biofilm formation, hemolytic activity, cell adherence, virulence and expression of virulence factors were evaluated. compared to the parenta ...201121621932
insight into the interaction of metal ions with troa from streptococcus suis.the scavenging ability of sufficient divalent metal ions is pivotal for pathogenic bacteria to survive in the host. atp-binding cassette (abc)-type metal transporters provide a considerable amount of different transition metals for bacterial growth. troa is a substrate binding protein for uptake of multiple metal ions. however, the function and structure of the troa homologue from the epidemic streptococcus suis isolates (sstroa) have not been characterized.201121611125
[construction and in vitro assay of the sortase bcd geneknock-out mutant of streptococcus suis 2].streptococcus suis 2 is an emerging zoonotic pathogen responsible for a wide range of life-threatening diseases in pigs and humans. in this study, we investigated the functionality of one of streptococcus suis 2 sortases, known as the srtbcd.201121604553
understanding streptococcus suis serotype 2 infection in pigs through a transcriptional approach.abstract: background: streptococcus suis serotype 2 (s. suis 2) is an important pathogen of pigs. s suis 2 infections have high mortality rates and are characterized by meningitis, septicemia and pneumonia. s. suis 2 is also an emerging zoonotic agent and can infect humans that are exposed to pigs or their by-products. to increase our knowledge of the pathogenesis of meningitis, septicemia and pneumonia in pigs caused by s. suis 2, we profiled the response of peripheral blood mononuclear cells ( ...201121599948
transcellular migration of neutrophil granulocytes through the blood-cerebrospinal fluid barrier after infection with streptococcus suis.abstract: background: a critical point during the course of bacterial meningitis is the excessive influx of polymorphnuclear neutrophils (pmns) from the blood into the brain. both paracellular and transcellular routes of leukocyte transmigration through the blood-brain barrier have been described in cns diseases so far. thus, we investigated the mechanism of pmn transmigration through the blood-csf barrier under inflammatory conditions. methods: in an "inverted" transwell culture model of the bl ...201121592385
enzymatic characterization of isocitrate dehydrogenase from an emerging zoonotic pathogen streptococcus suis.streptococcus suis, a gram-positive coccus, is an emerging zoonotic pathogen for both humans and pigs, but little is known about the properties of its metabolic enzymes. isocitrate dehydrogenase (idh) is a key regulatory enzyme in the citric acid cycle that catalyzes the oxidative decarboxylation of isocitrate yielding α-ketoglutarate and nad(p)h. here, we report the overexpression and enzymatic characterization of idh from s.suis serotype 2 chinese highly virulent strain 05zyh33 (ssidh). the mo ...201121586311
complete genome sequence of streptococcus suis serotype 3 strain st3.streptococcus suis is a zoonotic pathogen, causing economic loss in swine industry, and is also a threat to human health. to date, the mechanism of pathogenisis is not fully understood. here, we report the complete genome sequence of s. suis strain st3 of serotype 3, which provides opportunities to reveal genetic basis of infection of s. suis non-serotype 2 strains.201121572001
meningitis, sepsis and endocarditis among workers occupationally exposed to pigs.background: workers exposed to pigs can develop meningitis, sepsis or endocarditis due to infection with streptococcus suis transmitted from pigs to man. aims: to estimate the risk of these diseases. methods: we used the occupational hospitalization register (ohr) which holds information about occupation and hospital treatments for all adults in denmark. a dynamic population of male workers exposed to pigs was identified every year from 1995 to 2006 by occupational and industrial groups. first h ...201121562074
expression of plectasin in pichia pastoris and its characterization as a new antimicrobial peptide against staphyloccocus and streptococcus.recombinant plectasin, the first fungus defensin, was expressed in pichia pastoris and purified, and its physical, chemical and antimicrobial characteristics were studied. following a 120h induction of recombinant yeast, the amount of total secreted protein reached 748.63μg/ml. the percentage of recombinant plectasin was estimated to be 71.79% of the total protein. after purification with a sephadex g-25 column and rp-hplc, the identity of plectasin was verified by maldi-tof ms. plectasin exhibi ...201121558006
probing genomic diversity and evolution of streptococcus suis serotype 2 by nimblegen tiling arrays.abstract: background: our previous studies revealed that a new disease form of streptococcal toxic shock syndrome (stss) is associated with specific streptococcus suis serotype 2 (ss2) strains. to achieve a better understanding of the pathogenicity and evolution of ss2 at the whole-genome level, comparative genomic analysis of 18 ss2 strains, selected on the basis of virulence and geographic origin, was performed using nimblegen tiling arrays. results: our results demonstrate that ss2 isolates h ...201121554741
the pathogenicity island-like dna segment associated with chinese outbreak strain of streptococcus suis serotype 2 is absent in the united states isolates.to determine if the 2005 chinese outbreak strain of streptococcus suis is circulating in the united states, three different pcr primer-pairs derived from the nucleotide sequences surrounding and internal to the unique pathogenicity island -like dna segment of the chinese outbreak strain (strain 05zyh33) were used to screen 290 swine isolates of s. suis obtained from different locations. the first primer pair amplified an approximately 1000-bp fragment from 47 (16%) of the united states isolates ...201121537402
genotypic profile of streptococcus suis serotype 2 and clinical features of infection in humans, thailand.to examine associations between clinical features of streptococcus suis serotype 2 infections in humans in thailand and genotypic profiles of isolates, we conducted a retrospective study during 2006-2008. of 165 patients for whom bacterial cultures of blood, cerebrospinal fluid, or both were positive for s. suis serotype 2, the major multilocus sequence types (sts) found were st1 (62.4%) and st104 (25.5%); the latter is unique to thailand. clinical features were examined for 158 patients. infect ...201121529392
diversity and virulence factors of streptococcus suis. 201121498962
influence of a pig respiratory disease on the pharmacokinetic behaviour of amoxicillin after oral ad libitum administration in medicated feed.the pharmacokinetic properties of amoxicillin in healthy and respiratory-diseased pigs were studied, after ad libitum administration of medicated feed. in addition, amoxicillin dose linearity and drug penetration into respiratory tract tissues were evaluated in diseased animals. the respiratory disease involves porcine reproductive and respiratory syndrome virus and bacterial agents such as pasteurella multocida, bordetella bronchiseptica and streptococcus suis. typical clinical signs and gross ...201121492192
magnetic properties and structural characterization of iron oxide nanoparticles formed by streptococcus suis dpr and four mutants.streptococcus suis dpr belongs to the dps family of bacterial and archaeal proteins that oxidize fe(2+) to fe(3+) to protect microorganisms from oxidative damage. the oxidized iron is subsequently deposited as ferrihydrite inside a protein cavity, resulting in the formation of an iron core. the size and the magnetic properties of the iron core have attracted considerable attention for nanotechnological applications in recent years. here, the magnetic and structural properties of the iron core in ...201121487937
[purification and biological activities analysis of streptococcus suis serotype 2 suilysin.]aim: to explore the purification methods of wild-type and recombinant suilysin and to evaluate their biological activities. methods: wild-type suilysin was purified by ammonium sulfate precipitation, anion-exchange chromatography and hydrophobic chromatography in turn, while recombinant suilysin was first refolded and purified by immobilized metal ion affinity chromatography, and further purified by thiopropyl sepharose 6b. the biological activities were evaluated by hemolysis test, cytotoxicity ...201121481309
identification of genes and genomic islands correlated with high pathogenicity in streptococcus suis using whole genome tiling microarrays.streptococcus suis is an important zoonotic pathogen that can cause meningitis and sepsis in both pigs and humans. infections in humans have been sporadic worldwide but two severe outbreaks occurred in china in recent years, while infections in pigs are a major problem in the swine industry. some s. suis strains are more pathogenic than others with 2 sequence types (st), st1 and st7, being well recognized as highly pathogenic. we analyzed 31 isolates from 23 serotypes and 25 sts by nimblegen til ...201121479213
streptococcus suis causes septic arthritis and bacteremia: phenotypic characterization and molecular confirmation.streptococcus suis is a swine pathogen that causes meningitis, septicemia, pneumonia, and endocarditis. the first case of human s. suis infection was reported in denmark in 1968, and since then, this infection with has been reported in many countries, especially in southeast asia because of the high density of pigs in this region. we report the case of a patient with septic arthritis and bacteremia caused by s. suis. cases in which s. suis is isolated from the joint fluid are very rare, and to t ...201121474987
[acute streptococcus suis meningitis in a pig breeder.] 201121474211
slaughterhouse pigs are a major reservoir of streptococcus suis serotype 2 capable of causing human infection in southern vietnam.streptococcus suis is a pathogen of major economic significance to the swine industry and is increasingly recognized as an emerging zoonotic agent in asia. in vietnam, s. suis is the leading cause of bacterial meningitis in adult humans. zoonotic transmission is most frequently associated with serotype 2 strains and occupational exposure to pigs or consumption of infected pork. to gain insight into the role of pigs for human consumption as a reservoir for zoonotic infection in southern vietnam, ...201121464930
plasma concentrations resulting from florfenicol preparations given to pigs in their drinking water.florfenicol administered through the drinking water has been recommended as a metaphylactic antibacterial drug to control outbreaks of respiratory diseases in pigs caused by strains of actinobacillus pleuropneumoniae and pasteurella multocida, yet it is difficult to pinpoint in practice when the drug is given metaphylactically or therapeutically. further, pigs are likely to reject florfenicol-medicated water, and plasma concentrations of the drug are likely to be marginal for diseases caused by ...201121454858
acute-phase proteins: as diagnostic tool.the varied reactions of the host to infection, inflammation, or trauma are collectively known as the acute-phase response and encompass a wide range of pathophysiological responses such as pyrexia, leukocytosis, hormone alterations, and muscle protein depletion combining to minimize tissue damage while enhancing the repair process. the mechanism for stimulation of hepatic production of acute-phase proteins is by proinflammatory cytokines. the functions of positive acute-phase proteins (app) are ...201121430962
toll-like receptor 2 is partially involved in the activation of murine astrocytes by streptococcus suis, an important zoonotic agent of meningitis.the murine astrocyte response to virulent streptococcus suis, a swine and an emerging human meningitis-causing pathogen, is reported. albeit astrocytes do not internalize s. suis, all s. suis strains studied enhanced toll-like receptor (tlr)2 expression and the production of pro-inflammatory cytokines and inducible nitric oxide synthase. cell wall components and hemolysin (suilysin) are shown to be mainly responsible for cell activation. astrocytes from tlr2 knockout mice presented a partial but ...201121429596
optimal combinations of acute phase proteins for detecting infectious disease in pigs.abstract: the acute phase protein (app) response is an early systemic sign of disease, detected as substantial changes in app serum concentrations and most disease states involving inflammatory reactions give rise to app responses. to obtain a detailed picture of the general utility of porcine apps to detect any disease with an inflammatory component seven porcine apps were analysed in serum sampled at regular intervals in six different experimental challenge groups of pigs, including three bact ...201121414190
risk factors of streptococcus suis infection in vietnam. a case-control study.streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across south east asia and the most common cause of acute bacterial meningitis in adults in vietnam. little is known of the risk factors underlying the disease.201121408132
complete genome sequence of streptococcus suis serotype 14 strain js14.streptococcus suis is an important zoonotic agent leading to a variety of diseases in swine and can be transmitted to human beings upon close contact. here, we report the complete genome sequence of s. suis serotype 14 strain js14 which was isolated from a diseased pig in jiangsu province, china.201121398551
epidemiological characteristics of pulmonary pneumocystosis and concurrent infections in pigs in jeju island, korea.epidemiological characteristics of swine pulmonary pneumocystis (p.) carinii and concurrent infections were surveyed on jeju island, korea, within a designated period in 172 pigs submitted from 54 farms to the department of veterinary medicine, jeju national university. the submitted cases were evaluated by histopathology, immunohistochemistry, pcr/rt-pcr, and bacteriology. p. carinii infection was confirmed in 39 (22.7%) of the 172 pigs. histopathologically, the lungs had moderate to severe lym ...201121368558
the sspa subtilisin-like protease of streptococcus suis triggers a pro-inflammatory response in macrophages through a non-proteolytic mechanism.streptococcus suis is a major swine pathogen worldwide that causes meningitis, septicemia, arthritis, and endocarditis. using animal models, a surface-associated subtilisin-like protease (sspa) has recently been shown to be an important virulence factor for s. suis. in this study, we hypothesized that the s. suis sspa subtilisin-like protease may modulate cytokine secretion by macrophages thus contributing to the pathogenic process of meningitis.201121362190
role of glucose and ccpa in capsule expression and virulence of streptococcus suis.streptococcus suis is one of the most important pathogens in pigs and is also an emerging zoonotic agent. after crossing the epithelial barrier, s. suis causes bacteraemia, resulting in meningitis, endocarditis and bronchopneumonia. since the host environment seems to be an important regulatory component for virulence, we related expression of virulence determinants of s. suis to glucose availability during growth and to the sugar metabolism regulator catabolite control protein a (ccpa). we foun ...201121349980
incidence and presence of virulence factors of streptococcus suis infection in slaughtered pigs from chiang mai, thailand.this study was designed to determine the incidence of streptococcus suis infection in slaughtered pigs raised in industrial facility and backyard system in chiang mai city, thailand. a total of 90 tonsils and submaxillary salivary gland/lymph node samples from slaughtered pigs raised in industrial facility and 122 samples from slaughtered pigs raised in backyard system were collected. isolation and identification of s. suis were conducted using standard bacteriological methods. farm management a ...201021329323
parasitic bronchitis causes problems in cattle.parasitic bronchitis (lungworm, husk) in cattle lead poisoning in cattle associated with bonfire ash deaths of ewes associated with faulty administration of boluses streptococcus suis associated with respiratory and nervous disease in pigs blackhead and mycoplasmosis causing losses in turkeys these are among matters discussed in the veterinary laboratories agency's (vla's) disease surveillance report for october.201021262710
increase in the prevalence of johne's disease in sheep in scotland.increased prevalence of johne's disease in sheep; abomasal damage in young cattle due to ostertagiosis; parasitic gastroenteritis in young sheep due to nematodirus, teladorsagia and chabertia species; streptococcus suis serotype 2 associated with a range of clinical signs in pigs; respiratory cryptosporidiosis confirmed in wild red grouse. these are among matters discussed in the disease surveillance report for october 2010 from sac consulting: veterinary services (sac c vs).201121257530
microarray analyses of thp-1 cells infected with streptococcus suis serotype 2.streptococcus suis serotype 2 (s. suis 2) is a pathogen responsible for several diseases in both pigs and humans. to gain more insight into the pathogenesis of this organism, an oligonucleotide (oligo)-based microarray was used to investigate gene expression changes in human monocytic cells (thp-1) in response to exposure to s. suis 2 strain sc19. a total of 328 differentially expressed genes were identified. these differentially expressed genes belonged to a variety of functional categories, in ...201021255946
gi-type t4ss-mediated horizontal transfer of the 89k pathogenicity island in epidemic streptococcus suis serotype 2.pathogenicity islands (pais), a distinct type of genomic island (gi), play important roles in the rapid adaptation and increased virulence of pathogens. 89k is a newly identified pai in epidemic streptococcus suis isolates that are related to the two recent large-scale outbreaks of human infection in china. however, its mechanism of evolution and contribution to the epidemic spread of s. suis 2 remain unknown. in this study, the potential for mobilization of 89k was evaluated, and its putative t ...201121244532
preparation and pharmacokinetics of ceftiofur sodium liposomes in cows.the objective of this study was to prepare ceftiofur sodium liposomes and assess their physical properties, stability, antibacterial effects, and pharmacokinetics. these liposomes appeared as a milky, light yellow suspension with encapsulation efficiency at 57.2 ± 1.17%, and there were no significant changes in all estimated indexes at 4 °c for 90 days. the minimum inhibitory concentrations of liposomes were all 1/4th that of ceftiofur sodium against streptococcus suis, staphylococcus aureus, es ...201121219342
the antimicrobial resistance patterns and associated determinants in streptococcus suis isolated from humans in southern vietnam, 1997-2008.streptococcus suis is an emerging zoonotic pathogen and is the leading cause of bacterial meningitis in adults in vietnam. systematic data on the antimicrobial susceptibility profiles of s. suis strains isolated from human cases are lacking. we studied antimicrobial resistance and associated resistance determinants in s. suis isolated from patients with meningitis in southern vietnam.201121208459
induction of protective immune response against streptococcus suis serotype 2 infection by the surface antigen hp0245.streptococcus suis serotype 2 (ss2) is an emerging zoonotic pathogen. prevention and control of the diseases caused by ss2 bacteria are hampered by the lack of effective vaccines. we report that an in vivo-induced protein hp0245 was located at the cell surface of ss2. the extracellular peptide of hp0245 was produced in escherichia coli bl21 (de3). its immunogenicity was compared with ss2 bacterin. like ss2 bacterin, protein hp0245(ec) formulated in aluminum hydroxide adjuvant provided 100% prote ...201121204934
reduced virulence is an important characteristic of biofilm infection of streptococcus suis.streptococcus suis 2 (ss2) is a zoonotic pathogen that can participate in biofilm formation to survive in hostile environments. in this study, virulent ss2 strains ha9801 and zy05719 displayed increased biofilm formation compared with ss2 avirulent strain t15. in addition, a 58% reduction in adherence to hep-2 cells was observed for ha9801 biofilm cells, compared with ha9801 planktonic cells. the 50% lethal dose (ld(50) ) of biofilm cells was 40-fold greater than that of planktonic cells. quanti ...201121204925
crystal structure of cytotoxin protein suilysin from streptococcus suis.cholesterol-dependent cytolysins (cdc) are pore forming toxins. a prototype of the cdc family members is perfringolysin o (pfo), which directly binds to the cell membrane enriched in cholesterol, causing cell lysis. however, an exception of this general observation is intermedilysin (ily) of streptococcus intermedius, which requires human cd59 as a receptor in addition to cholesterol for its hemolytic activity. a possible explanation of this functional difference is the conformational variation ...201021204001
distribution of capsular serotypes and virulence markers of streptococcus suis isolated from pigs with polyserositis in korea.the objective of this study was to determine the capsular serotypes and potential virulence factors of streptococcus suis isolated from pigs with polyserositis. among the 24 isolates evaluated, serotype 3 [7 (29%) of the isolates] and serotype 4 [5 (21%)] were the most common. the isolates were also studied for the presence of the genes mrp, epf, and sly, which encode muramidase-released protein (mrp), extracellular factor (ef), and suilysin (sly), respectively. of the 24 isolates, 8 carried mrp ...201021197232
endocarditis-associated brain lesions in slaughter pigs.left-sided valvular endocarditis (lsve) is a common finding in slaughter pigs. the lesion is often associated with renal thromboembolism, but information on embolization to other organs is sparse. this study focuses on the presence and type of endocarditis-associated brain lesions (eabls). the brains of 20 slaughter pigs with spontaneously arising lsve and 11 controls were examined by sectioning half of a formalin-fixed brain into 4mm slices for histological examination. the aetiology of the end ...201021168147
contribution of the rgg transcription regulator to metabolism and virulence of streptococcus suis serotype 2.the rgg-like regulators, a family of transcription factors commonly found in many gram-positive bacteria, play multiple roles, especially in the control of pathogen virulence. here, we report an rgg homologue from a chinese isolate, 05zyh33, of streptococcus suis serotype 2 (ss2). deletion of the rgg gene in ss2 increased its adhesion to hep-2 cells and hemolytic activity in vitro. significantly, inactivation of the rgg gene attenuated ss2 virulence in an experimental piglet infection model. usi ...201021149588
the minor pilin subunit sgp2 is necessary for assembly of the pilus encoded by the srtg cluster of streptococcus suis.gram-positive pili are composed of covalently bound pilin subunits whose assembly is mediated via a pilus-specific sortase(s). major subunits constitute the pilus backbone and are therefore essential for pilus formation. minor subunits are also incorporated into the pilus, but they are considered to be dispensable for backbone formation. the srtg cluster is one of the putative pilus gene clusters identified in the major swine pathogen streptococcus suis. it consists of one sortase gene (srtg) an ...201021148736
streptococcus suis infection induces to bacterial accumulation in the kidney.although a streptococcus suis infection was recently expanded, the study of s. suis has not had enough attention. in this study, bacterial kinetics of s. suis were investigated for seven days of infection in a mouse model. survival rates showed that 5.0 × 10(7) cfu ml(-1) of s. suis infection caused death in 30% of mice subjects. streptococcal kinetics from 10(4) to 10(7) cfu ml(-1) were detected in the brain, kidney, lung, spleen and urine two days post-infection and still detected in both kidn ...201021134439
htps, a novel immunogenic cell surface-exposed protein of streptococcus suis, confers protection in mice.streptococcal histidine triad protein was identified recently as a cell surface-associated protein family. five members of this family (phta, phtb, phtd, phte and htpa), derived from streptococcus pneumoniae and streptococcus pyogenes, have been shown as antigens that confer protection to the host on infection. in this report, a gene sequence highly homologous to htpa and phtd (designated htps, the histidine triad protein of streptococcus suis) was identified from s. suis 2 chinese strain 05zyh3 ...201021133988
different genetic elements carrying the tet(w) gene in two human clinical isolates of streptococcus suis.the genetic support for tet(w), an emerging tetracycline resistance determinant, was studied in two strains of streptococcus suis, ssca and ssud, both isolated in italy from patients with meningitis. two completely different tet(w)-carrying genetic elements, sharing only a tet(w)-containing segment barely larger than the gene, were found in the two strains. the one from strain ssca was nontransferable, and aside from an erm(b)-containing insertion, it closely resembled a genomic island recently ...201021115784
trigger factor of streptococcus suis is involved in stress tolerance and virulence.streptococcus suis serotype 2 is an important zoonotic pathogen that causes serious diseases such as meningitis, septicemia, endocarditis, arthritis and septic shock in pigs and humans. little is known about the regulation of virulence gene expression in s. suis serotype 2. in this study, we cloned and deleted the entire tig gene from the chromosome of s. suis serotype 2 sc21 strain, and constructed a mutant strain (δtig) and a complementation strain (cδtig). the results demonstrated that the ti ...201021093574
histologic and bacteriologic findings in valvular endocarditis of slaughter-age pigs.endocarditis lesions from 117 slaughter pigs were examined pathologically and etiologically in addition to 90 control hearts with cardiac valves. lesions were located on the valves; however, the lesions had extended to the walls in 21 cases (18%). lesions predominated on the mitral valve (59%). a total of 28 cases, from which no growth was obtained or a contamination flora was grown, were screened by fluorescence in situ hybridization (fish) for bacteria (general bacterial probe) and probes spec ...201021088176
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