Science.gov

Sample records for pathogen streptococcus suis

  1. Streptococcus suis infection

    PubMed Central

    Feng, Youjun; Zhang, Huimin; Wu, Zuowei; Wang, Shihua; Cao, Min; Hu, Dan; Wang, Changjun

    2014-01-01

    Streptococcus suis (S. suis) is a family of pathogenic gram-positive bacterial strains that represents a primary health problem in the swine industry worldwide. S. suis is also an emerging zoonotic pathogen that causes severe human infections clinically featuring with varied diseases/syndromes (such as meningitis, septicemia, and arthritis). Over the past few decades, continued efforts have made significant progress toward better understanding this zoonotic infectious entity, contributing in part to the elucidation of the molecular mechanism underlying its high pathogenicity. This review is aimed at presenting an updated overview of this pathogen from the perspective of molecular epidemiology, clinical diagnosis and typing, virulence mechanism, and protective antigens contributing to its zoonosis. PMID:24667807

  2. Isolation, Characterization and Biological Properties of Membrane Vesicles Produced by the Swine Pathogen Streptococcus suis

    PubMed Central

    Haas, Bruno; Grenier, Daniel

    2015-01-01

    Streptococcus suis, more particularly serotype 2, is a major swine pathogen and an emerging zoonotic agent worldwide that mainly causes meningitis, septicemia, endocarditis, and pneumonia. Although several potential virulence factors produced by S. suis have been identified in the last decade, the pathogenesis of S. suis infections is still not fully understood. In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material. A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors. Biological assays confirmed that S. suis MVs possess active subtilisin-like protease (SspA) and DNase (SsnA). S. suis MVs degraded neutrophil extracellular traps, a property that may contribute to the ability of the bacterium to escape the host defense response. MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier. The present study brought evidence that S. suis MVs may play a role as a virulence factor in the pathogenesis of S. suis infections, and given their composition be an excellent candidate for vaccine development. PMID:26110524

  3. Isolation, Characterization and Biological Properties of Membrane Vesicles Produced by the Swine Pathogen Streptococcus suis.

    PubMed

    Haas, Bruno; Grenier, Daniel

    2015-01-01

    Streptococcus suis, more particularly serotype 2, is a major swine pathogen and an emerging zoonotic agent worldwide that mainly causes meningitis, septicemia, endocarditis, and pneumonia. Although several potential virulence factors produced by S. suis have been identified in the last decade, the pathogenesis of S. suis infections is still not fully understood. In the present study, we showed that S. suis produces membrane vesicles (MVs) that range in diameter from 13 to 130 nm and that appear to be coated by capsular material. A proteomic analysis of the MVs revealed that they contain 46 proteins, 9 of which are considered as proven or suspected virulence factors. Biological assays confirmed that S. suis MVs possess active subtilisin-like protease (SspA) and DNase (SsnA). S. suis MVs degraded neutrophil extracellular traps, a property that may contribute to the ability of the bacterium to escape the host defense response. MVs also activated the nuclear factor-kappa B (NF-κB) signaling pathway in both monocytes and macrophages, inducing the secretion of pro-inflammatory cytokines, which may in turn contribute to increase the permeability of the blood brain barrier. The present study brought evidence that S. suis MVs may play a role as a virulence factor in the pathogenesis of S. suis infections, and given their composition be an excellent candidate for vaccine development.

  4. A hypothetical model of host-pathogen interaction of Streptococcus suis in the gastro-intestinal tract

    PubMed Central

    Ferrando, Maria Laura; Schultsz, Constance

    2016-01-01

    ABSTRACT Streptococcus suis (SS) is a zoonotic pathogen that can cause systemic infection in pigs and humans. The ingestion of contaminated pig meat is a well-established risk factor for zoonotic S. suis disease. In our studies, we provide experimental evidence that S. suis is capable to translocate across the host gastro-intestinal tract (GIT) using in vivo and in vitro models. Hence, S. suis should be considered an emerging foodborne pathogen. In this addendum, we give an overview of the complex interactions between S. suis and host-intestinal mucosa which depends on the host origin, the serotype and genotype of S. suis, as well as the presence and expression of virulence factors involved in host-pathogen interaction. Finally, we propose a hypothetical model of S. suis interaction with the host-GIT taking in account differences in conditions between the porcine and human host. PMID:26900998

  5. Experimental infection of specific pathogen free piglets with French strains of Streptococcus suis capsular type 2.

    PubMed Central

    Berthelot-Hérault, F; Cariolet, R; Labbé, A; Gottschalk, M; Cardinal, J Y; Kobisch, M

    2001-01-01

    A standardized model of Streptococcus suis type 2 infection in specific-pathogen-free piglets, housed in high-security barns, was used to compare the virulence of 3 French field strains of S. suis serotype 2 isolated from tonsils of a healthy pig (strain 65) or from diseased pigs (meningitis, strain 166', or septicemia, strain 24). In one of the 2 trials, 7-week-old pigs, in 3 groups of 8, were inoculated intravenously with 2 x 10(8) colony-forming units of S. suis type 2. In each group, 1 uninfected animal was a sentinel. Eight animals were also used as negative control group. The experiment was repeated under similar conditions with strains 65 and 166'. Virulence differed markedly among these S. suis strains when clinical signs, zootechnical performances, lesions, and bacteriological data were analyzed. Strain 65 did not induce clinical signs in inoculated pigs. In contrast, pigs infected with the other 2 strains exhibited clinical signs and typical lesions of S. suis type 2 infections. Differences in virulence were also observed between the 2 virulent strains. Sentinel animals exhibited the same manifestations as those recorded in inoculated piglets. Results were similar in the second trial, indicating that under the present experimental conditions, results were reproducible. The standardized conditions described in this study could be a useful tool to further study about the S. suis infection. PMID:11480526

  6. Antimicrobial activity of nisin against the swine pathogen Streptococcus suis and its synergistic interaction with antibiotics.

    PubMed

    Lebel, Geneviève; Piché, Fanny; Frenette, Michel; Gottschalk, Marcelo; Grenier, Daniel

    2013-12-01

    Streptococcus suis serotype 2 is known to cause severe infections in pigs, including meningitis, endocarditis and pneumonia. Furthermore, this bacterium is considered an emerging zoonotic agent. Recently, increased antibiotic resistance in S. suis has been reported worldwide. The objective of this study was to evaluate the potential of nisin, a bacteriocin of the lantibiotic class, as an antibacterial agent against the pathogen S. suis serotype 2. In addition, the synergistic activity of nisin in combination with conventional antibiotics was assessed. Using a plate assay, the nisin-producing strain Lactococcus lactis ATCC 11454 proved to be capable of inhibiting the growth of S. suis (n=18) belonging to either sequence type (ST)1, ST25, or ST28. In a microdilution broth assay, the minimum inhibitory concentration (MIC) of purified nisin ranged between 1.25 and 5 μg/mL while the minimum bactericidal concentration (MBC) was between 5 and 10 μg/mL toward S. suis. The use of a capsule-deficient mutant of S. suis indicated that the presence of this polysaccharidic structure has no marked impact on susceptibility to nisin. Following treatment of S. suis with nisin, transmission electron microscopy observations revealed lysis of bacteria resulting from breakdown of the cell membrane. A time-killing curve showed a rapid bactericidal activity of nisin. Lastly, synergistic effects of nisin were observed in combination with several antibiotics, including penicillin, amoxicillin, tetracycline, streptomycin and ceftiofur. This study brought clear evidence supporting the potential of nisin for the prevention and treatment of S. suis infections in pigs.

  7. Deregulated balance of omega-6 and omega-3 polyunsaturated fatty acids following infection by the zoonotic pathogen Streptococcus suis.

    PubMed

    Lachance, Claude; Segura, Mariela; Dominguez-Punaro, Maria C; Wojewodka, Gabriella; De Sanctis, Juan B; Radzioch, Danuta; Gottschalk, Marcelo

    2014-05-01

    Streptococcus suis is an important swine pathogen and an emergent zoonotic pathogen. Excessive inflammation caused by S. suis is responsible for early high mortality in septic shock-like syndrome cases. Polyunsaturated fatty acids (PUFAs) may contribute to regulating inflammatory processes. This study shows that mouse infection by S. suis is accompanied by an increase of arachidonic acid, a proinflammatory omega-6 (ω-6) PUFA, and by a decrease of docosahexaenoic acid, an anti-inflammatory ω-3 PUFA. Macrophages infected with S. suis showed activation of mitogen-activated protein kinase pathways and cyclooxygenase-2 upregulation. Fenretinide, a synthetic vitamin A analog, reduced in vitro expression of inflammatory mediators. Pretreatment of mice with fenretinide significantly improved their survival by reducing systemic proinflammatory cytokines during the acute phase of an S. suis infection. These findings indicate a beneficial effect of fenretinide in diminishing the expression of inflammation and improving survival during an acute infection by a virulent S. suis strain.

  8. Deregulated Balance of Omega-6 and Omega-3 Polyunsaturated Fatty Acids following Infection by the Zoonotic Pathogen Streptococcus suis

    PubMed Central

    Lachance, Claude; Segura, Mariela; Dominguez-Punaro, Maria C.; Wojewodka, Gabriella; De Sanctis, Juan B.; Radzioch, Danuta

    2014-01-01

    Streptococcus suis is an important swine pathogen and an emergent zoonotic pathogen. Excessive inflammation caused by S. suis is responsible for early high mortality in septic shock-like syndrome cases. Polyunsaturated fatty acids (PUFAs) may contribute to regulating inflammatory processes. This study shows that mouse infection by S. suis is accompanied by an increase of arachidonic acid, a proinflammatory omega-6 (ω-6) PUFA, and by a decrease of docosahexaenoic acid, an anti-inflammatory ω-3 PUFA. Macrophages infected with S. suis showed activation of mitogen-activated protein kinase pathways and cyclooxygenase-2 upregulation. Fenretinide, a synthetic vitamin A analog, reduced in vitro expression of inflammatory mediators. Pretreatment of mice with fenretinide significantly improved their survival by reducing systemic proinflammatory cytokines during the acute phase of an S. suis infection. These findings indicate a beneficial effect of fenretinide in diminishing the expression of inflammation and improving survival during an acute infection by a virulent S. suis strain. PMID:24549326

  9. Candidate proteomic biomarkers for three genogroups of the swine pathogen Streptococcus suis serotype 2.

    PubMed

    Atanassov, Christo; Bonifait, Laetitia; Perivier, Marylise; Gottschalk, Marcelo; Grenier, Daniel

    2015-04-04

    Streptococcus suis, more specifically serotype 2, is a major swine pathogen and an emerging zoonotic agent that causes severe infections such as meningitis, endocarditis, and septicemia. In this study, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI) was used to investigate the protein expression profiles of 45 strains of S. suis serotype 2 that had previously been clustered by multilocus sequence typing (MLST) into three sequence types (ST1, ST25, and ST28) (n = 15 for each ST). The SELDI data were analyzed using the univariate Mann-Whitney and Kruskal-Wallis tests and multivariate statistical methods (heatmap/hierarchical clustering). The heatmap identified 136 cell proteins, and hierarchical clustering provided a 100% correct classification of all fifteen ST1 and ST25 strains and thirteen of the fifteen ST28 strains (87% correct). The univariate statistical analyses of the SELDI protein expression profiles identified nine significant proteins that discriminated the strains of the three STs of S. suis. Of these proteins, two were overexpressed in ST1 (5958 Da and 10249 Da), four in ST25 (5989 Da, 6646 Da, 7421 Da, and 9825 Da), and three in ST28 (4516 Da, 7833 Da, and 9342 Da). Two of the proteins associated with the ST28 strains (p4516 and p9342) were purified and were identified as a putative ABC transporter and a nucleoid-DNA-binding protein, respectively. SELDI analysis of 45 strains of S. suis allowed to identify nine statistically significant proteins that can be specifically correlated with either ST1, ST25 or ST28. The possible involvement of the overexpressed proteins in the pathology of S. suis infections will require further investigation.

  10. Morin Attenuates Streptococcus suis Pathogenicity in Mice by Neutralizing Suilysin Activity

    PubMed Central

    Li, Gen; Lu, Gejin; Qi, Zhimin; Li, Hongen; Wang, Lin; Wang, Yanhui; Liu, Bowen; Niu, Xiaodi; Deng, Xuming; Wang, Jianfeng

    2017-01-01

    Streptococcus suis, a Gram-positive pathogen, is widely recognized as an important agent of swine infection, and it is also known to cause a variety of zoonoses, such as meningitis, polyarthritis and pneumonia. Suilysin (SLY), an extracellular pore-forming toxin that belongs to the cholesterol-dependent cytolysin family, is an essential virulence factor of S. suis capsular type 2 (SS2). Here, we found that morin hydrate (morin), a natural flavonoid that lacks anti-SS2 activity, inhibits the hemolytic activity of SLY, protects J774 cells from SS2-induced injury and protects mice from SS2 infection. Further, by molecular modeling and mutational analysis, we found that morin binds to the “stem” domain 2 in SLY and hinders its transformation from the monomer form to the oligomer form, which causes the loss of SLY activity. Our study demonstrates that morin hinders the cell lysis activity of SLY through a novel mechanism of interrupting the heptamer formation. These findings may lead to the development of promising therapeutic candidates for the treatment of SS2 infections. PMID:28373868

  11. Characterization of a Streptococcus suis tet(O/W/32/O)-Carrying Element Transferable to Major Streptococcal Pathogens

    PubMed Central

    Palmieri, Claudio; Magi, Gloria; Mingoia, Marina; Bagnarelli, Patrizia; Ripa, Sandro; Varaldo, Pietro E.

    2012-01-01

    Mosaic tetracycline resistance determinants are a recently discovered class of hybrids of ribosomal protection tet genes. They may show different patterns of mosaicism, but their final size has remained unaltered. Initially thought to be confined to a small group of anaerobic bacteria, mosaic tet genes were then found to be widespread. In the genus Streptococcus, a mosaic tet gene [tet(O/W/32/O)] was first discovered in Streptococcus suis, an emerging drug-resistant pig and human pathogen. In this study, we report the molecular characterization of a tet(O/W/32/O) gene-carrying mobile element from an S. suis isolate. tet(O/W/32/O) was detected, in tandem with tet(40), in a circular 14,741-bp genetic element (39.1% G+C; 17 open reading frames [ORFs] identified). The novel element, which we designated 15K, also carried the macrolide resistance determinant erm(B) and an aminoglycoside resistance four-gene cluster including aadE (streptomycin) and aphA (kanamycin). 15K appeared to be an unstable genetic element that, in the absence of recombinases, is capable of undergoing spontaneous excision under standard growth conditions. In the integrated form, 15K was found inside a 54,879-bp integrative and conjugative element (ICE) (50.5% G+C; 55 ORFs), which we designated ICESsu32457. An ∼1.3-kb segment that apparently served as the att site for excision of the unstable 15K element was identified. The novel ICE was transferable at high frequency to recipients from pathogenic Streptococcus species (S. suis, Streptococcus pyogenes, Streptococcus pneumoniae, and Streptococcus agalactiae), suggesting that the multiresistance 15K element can successfully spread within streptococcal populations. PMID:22710115

  12. Genomic signatures of human and animal disease in the zoonotic pathogen Streptococcus suis.

    PubMed

    Weinert, Lucy A; Chaudhuri, Roy R; Wang, Jinhong; Peters, Sarah E; Corander, Jukka; Jombart, Thibaut; Baig, Abiyad; Howell, Kate J; Vehkala, Minna; Välimäki, Niko; Harris, David; Chieu, Tran Thi Bich; Van Vinh Chau, Nguyen; Campbell, James; Schultsz, Constance; Parkhill, Julian; Bentley, Stephen D; Langford, Paul R; Rycroft, Andrew N; Wren, Brendan W; Farrar, Jeremy; Baker, Stephen; Hoa, Ngo Thi; Holden, Matthew T G; Tucker, Alexander W; Maskell, Duncan J

    2015-03-31

    Streptococcus suis causes disease in pigs worldwide and is increasingly implicated in zoonotic disease in East and South-East Asia. To understand the genetic basis of disease in S. suis, we study the genomes of 375 isolates with detailed clinical phenotypes from pigs and humans from the United Kingdom and Vietnam. Here, we show that isolates associated with disease contain substantially fewer genes than non-clinical isolates, but are more likely to encode virulence factors. Human disease isolates are limited to a single-virulent population, originating in the 1920, s when pig production was intensified, but no consistent genomic differences between pig and human isolates are observed. There is little geographical clustering of different S. suis subpopulations, and the bacterium undergoes high rates of recombination, implying that an increase in virulence anywhere in the world could have a global impact over a short timescale.

  13. Use of Antibiotics and Antimicrobial Resistance in Veterinary Medicine as Exemplified by the Swine Pathogen Streptococcus suis.

    PubMed

    Seitz, Maren; Valentin-Weigand, Peter; Willenborg, Jörg

    2016-01-01

    Use of antimicrobial agents in veterinary medicine is essential to control infectious diseases, thereby keeping animals healthy and animal products safe for the consumer. On the other hand, development and spread of antimicrobial resistance is of major concern for public health. Streptococcus (S.) suis reflects a typical bacterial pathogen in modern swine production due to its facultative pathogenic nature and wide spread in the pig population. Thus, in the present review we focus on certain current aspects and problems related to antimicrobial use and resistance in S. suis as a paradigm for a bacterial pathogen affecting swine husbandry worldwide. The review includes (i) general aspects of antimicrobial use and resistance in veterinary medicine with emphasis on swine, (ii) genetic resistance mechanisms of S. suis known to contribute to bacterial survival under antibiotic selection pressure, and (iii) possible other factors which may contribute to problems in antimicrobial therapy of S. suis infections, such as bacterial persister cell formation, biofilm production, and co-infections. The latter shows that we hardly understand the complexity of factors affecting the success of antimicrobial treatment of (porcine) infectious diseases and underlines the need for further research in this field.

  14. Molecular Basis of Resistance to Selected Antimicrobial Agents in the Emerging Zoonotic Pathogen Streptococcus suis

    PubMed Central

    Gurung, Mamata; Tamang, Migma Dorji; Moon, Dong Chan; Kim, Su-Ran; Jeong, Jin-Ha; Jang, Geum-Chan; Jung, Suk-Chan; Park, Yong-Ho

    2015-01-01

    Characterization of 227 Streptococcus suis strains isolated from pigs during 2010 to 2013 showed high levels of resistance to clindamycin (95.6%), tilmicosin (94.7%), tylosin (93.8%), oxytetracycline (89.4%), chlortetracycline (86.8%), tiamulin (72.7%), neomycin (70.0%), enrofloxacin (56.4%), penicillin (56.4%), ceftiofur (55.9%), and gentamicin (55.1%). Resistance to tetracyclines, macrolides, aminoglycosides, and fluoroquinolone was attributed to the tet gene, erm(B), erm(C), mph(C), and mef(A) and/or mef(E) genes, aph(3′)-IIIa and aac(6′)-Ie-aph(2″)-Ia genes, and single point mutations in the quinolone resistance-determining region of ParC and GyrA, respectively. PMID:25903569

  15. Molecular Basis of Resistance to Selected Antimicrobial Agents in the Emerging Zoonotic Pathogen Streptococcus suis.

    PubMed

    Gurung, Mamata; Tamang, Migma Dorji; Moon, Dong Chan; Kim, Su-Ran; Jeong, Jin-Ha; Jang, Geum-Chan; Jung, Suk-Chan; Park, Yong-Ho; Lim, Suk-Kyung

    2015-07-01

    Characterization of 227 Streptococcus suis strains isolated from pigs during 2010 to 2013 showed high levels of resistance to clindamycin (95.6%), tilmicosin (94.7%), tylosin (93.8%), oxytetracycline (89.4%), chlortetracycline (86.8%), tiamulin (72.7%), neomycin (70.0%), enrofloxacin (56.4%), penicillin (56.4%), ceftiofur (55.9%), and gentamicin (55.1%). Resistance to tetracyclines, macrolides, aminoglycosides, and fluoroquinolone was attributed to the tet gene, erm(B), erm(C), mph(C), and mef(A) and/or mef(E) genes, aph(3')-IIIa and aac(6')-Ie-aph(2″)-Ia genes, and single point mutations in the quinolone resistance-determining region of ParC and GyrA, respectively.

  16. Deletion of ssnA Attenuates the Pathogenicity of Streptococcus suis and Confers Protection against Serovar 2 Strain Challenge

    PubMed Central

    Li, Miao; Cai, Ru-Jian; Li, Chun-Ling; Song, Shuai; Li, Yan; Jiang, Zhi-Yong; Yang, Dong-Xia

    2017-01-01

    Streptococcus suis serotype 2 (SS2) is a major porcine and human pathogen which causes arthritis, meningitis, and septicemia. Streptococcus suis nuclease A (SsnA) is a recently discovered deoxyribonuclease (DNase), which has been demonstrated to contribute to escape killing in neutrophil extracellular traps (NETs). To further determine the effects of ssnA on virulence, the ssnA deletion mutant (ΔssnA) and its complemented strain (C-ΔssnA) were constructed. The ability of ΔssnA mutant to interact with human laryngeal epithelial cell (Hep-2) was evaluated and it exhibited dramatically decreased ability to adhere to and invade Hep-2 cells. This mutation was found to exhibit significant attenuation of virulence when evaluated in CD1 mice, suggesting ssnA plays a critical role in the pathogenesis of SS2. Finally, we found that immunization with the ΔssnA mutant triggered both antibody responses and cell-mediated immunity, and conferred 80% protection against virulent SS2 challenge in mice. Taken together, our results suggest that ΔssnA represents an attractive candidate for designing an attenuated live vaccine against SS2. PMID:28081204

  17. Agents of the "suis-ide diseases" of swine: Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis.

    PubMed Central

    MacInnes, J I; Desrosiers, R

    1999-01-01

    In recent years, Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis have emerged as important pathogens of swine, particularly in high health status herds. Their association with a wide range of serious clinical conditions and has given rise to the moniker "suis-ide diseases." These organisms are early colonizers and, for that reason, are difficult to control by management procedures such as segregated early weaning. Vaccination, serodiagnostic testing, and even serotyping are complicated by the presence of multiple serotypes, cross-reactive antigens, and the absence of clear markers for virulence. In this review, we discuss our current understanding of the pathogenesis, epidemiology, and management of the causative agents of the "suis-ide diseases" of swine. Images Figure 1. Figure 2. Figure 3. PMID:10369563

  18. Streptococcus suis, an important pig pathogen and emerging zoonotic agent—an update on the worldwide distribution based on serotyping and sequence typing

    PubMed Central

    Goyette-Desjardins, Guillaume; Auger, Jean-Philippe; Xu, Jianguo; Segura, Mariela; Gottschalk, Marcelo

    2014-01-01

    Streptococcus suis is an important pathogen causing economic problems in the pig industry. Moreover, it is a zoonotic agent causing severe infections to people in close contact with infected pigs or pork-derived products. Although considered sporadic in the past, human S. suis infections have been reported during the last 45 years, with two large outbreaks recorded in China. In fact, the number of reported human cases has significantly increased in recent years. In this review, we present the worldwide distribution of serotypes and sequence types (STs), as determined by multilocus sequence typing, for pigs (between 2002 and 2013) and humans (between 1968 and 2013). The methods employed for S. suis identification and typing, the current epidemiological knowledge regarding serotypes and STs and the zoonotic potential of S. suis are discussed. Increased awareness of S. suis in both human and veterinary diagnostic laboratories and further establishment of typing methods will contribute to our knowledge of this pathogen, especially in regions where complete and/or recent data is lacking. More research is required to understand differences in virulence that occur among S. suis strains and if these differences can be associated with specific serotypes or STs. PMID:26038745

  19. Suicin 90-1330 from a nonvirulent strain of Streptococcus suis: a nisin-related lantibiotic active on gram-positive swine pathogens.

    PubMed

    LeBel, Geneviève; Vaillancourt, Katy; Frenette, Michel; Gottschalk, Marcelo; Grenier, Daniel

    2014-09-01

    Streptococcus suis serotype 2 is known to cause severe infections (meningitis, endocarditis, and septicemia) in pigs and is considered an emerging zoonotic agent. Antibiotics have long been used in the swine industry for disease treatment/prevention and growth promoters. This pattern of utilization resulted in the spread of antibiotic resistance in S. suis worldwide. Interestingly, pigs may harbor S. suis in their tonsils without developing diseases, while North American strains belonging to the sequence type 28 (ST28) are nonvirulent in animal models. Consequently, the aim of this study was to purify and characterize a bacteriocin produced by a nonvirulent strain of S. suis serotype 2, with a view to a potential therapeutic and preventive application. S. suis 90-1330 belonging to ST28 and previously shown to be nonvirulent in an animal model exhibited antibacterial activity toward all S. suis pathogenic isolates tested. The bacteriocin produced by this strain was purified to homogeneity by cationic exchange and reversed-phase fast protein liquid chromatography. Given its properties (molecular mass of <4 kDa, heat, pH and protease stability, and the presence of modified amino acids), the bacteriocin, named suicin 90-1330, belongs to the lantibiotic class. Using a DNA-binding fluorophore, the bacteriocin was found to possess a membrane permeabilization activity. When tested on other swine pathogens, the suicin showed activity against Staphylococcus hyicus and Staphylococcus aureus, whereas it was inactive against all Gram-negative bacteria tested. Amino acid sequencing of the purified bacteriocin showed homology (90.9% identity) with nisin U produced by Streptococcus uberis. The putative gene cluster involved in suicin production was amplified by PCR and sequence analysis revealed the presence of 11 open reading frames, including the structural gene and those required for the modification of amino acids, export, regulation, and immunity. Further studies will

  20. Suicin 90-1330 from a Nonvirulent Strain of Streptococcus suis: a Nisin-Related Lantibiotic Active on Gram-Positive Swine Pathogens

    PubMed Central

    LeBel, Geneviève; Vaillancourt, Katy; Frenette, Michel; Gottschalk, Marcelo

    2014-01-01

    Streptococcus suis serotype 2 is known to cause severe infections (meningitis, endocarditis, and septicemia) in pigs and is considered an emerging zoonotic agent. Antibiotics have long been used in the swine industry for disease treatment/prevention and growth promoters. This pattern of utilization resulted in the spread of antibiotic resistance in S. suis worldwide. Interestingly, pigs may harbor S. suis in their tonsils without developing diseases, while North American strains belonging to the sequence type 28 (ST28) are nonvirulent in animal models. Consequently, the aim of this study was to purify and characterize a bacteriocin produced by a nonvirulent strain of S. suis serotype 2, with a view to a potential therapeutic and preventive application. S. suis 90-1330 belonging to ST28 and previously shown to be nonvirulent in an animal model exhibited antibacterial activity toward all S. suis pathogenic isolates tested. The bacteriocin produced by this strain was purified to homogeneity by cationic exchange and reversed-phase fast protein liquid chromatography. Given its properties (molecular mass of <4 kDa, heat, pH and protease stability, and the presence of modified amino acids), the bacteriocin, named suicin 90-1330, belongs to the lantibiotic class. Using a DNA-binding fluorophore, the bacteriocin was found to possess a membrane permeabilization activity. When tested on other swine pathogens, the suicin showed activity against Staphylococcus hyicus and Staphylococcus aureus, whereas it was inactive against all Gram-negative bacteria tested. Amino acid sequencing of the purified bacteriocin showed homology (90.9% identity) with nisin U produced by Streptococcus uberis. The putative gene cluster involved in suicin production was amplified by PCR and sequence analysis revealed the presence of 11 open reading frames, including the structural gene and those required for the modification of amino acids, export, regulation, and immunity. Further studies will

  1. Detection of Streptococcus suis in Bioaerosols of Swine Confinement Buildings

    PubMed Central

    Bonifait, Laetitia; Veillette, Marc; Létourneau, Valérie; Grenier, Daniel

    2014-01-01

    Streptococcus suis is an important swine pathogen that can cause septicemia, meningitis, and pneumonia. Also recognized as an emerging zoonotic agent, it is responsible for outbreaks of human infections in Asian countries. Serotype 2 is the predominant isolate from diseased animals and humans. The aerosolization of S. suis in the air of swine confinement buildings (SCB) was studied. The presence of S. suis in bioaerosols was monitored in SCB where cases of infection had been reported and in healthy SCB without reported infections. Using a quantitative-PCR (qPCR) method, we determined the total number of bacteria (1 × 108 to 2 × 108 airborne/m3), total number of S. suis bacteria (4 × 105 to 10 × 105 airborne/m3), and number of S. suis serotype 2 and 1/2 bacteria (1 × 103 to 30 × 103 airborne/m3) present in the air. S. suis serotypes 2 and 1/2 were detected in the air of all growing/finishing SCB that had documented cases of S. suis infection and in 50% of healthy SCB. The total number of bacteria and total numbers of S. suis and S. suis serotype 2 and 1/2 bacteria were monitored in one positive SCB during a 5-week period, and it was shown that the aerosolized S. suis serotypes 2 and 1/2 remain airborne for a prolonged period. When the effect of aerosolization on S. suis was observed, the percentage of intact S. suis bacteria (showing cell membrane integrity) in the air might have been up to 13%. Finally S. suis was found in nasal swabs from 14 out of 21 healthy finishing-SCB workers, suggesting significant exposure to the pathogen. This report provides a better understanding of the aerosolization, prevalence, and persistence of S. suis in SCB. PMID:24632262

  2. Detection of Streptococcus suis in bioaerosols of swine confinement buildings.

    PubMed

    Bonifait, Laetitia; Veillette, Marc; Létourneau, Valérie; Grenier, Daniel; Duchaine, Caroline

    2014-06-01

    Streptococcus suis is an important swine pathogen that can cause septicemia, meningitis, and pneumonia. Also recognized as an emerging zoonotic agent, it is responsible for outbreaks of human infections in Asian countries. Serotype 2 is the predominant isolate from diseased animals and humans. The aerosolization of S. suis in the air of swine confinement buildings (SCB) was studied. The presence of S. suis in bioaerosols was monitored in SCB where cases of infection had been reported and in healthy SCB without reported infections. Using a quantitative-PCR (qPCR) method, we determined the total number of bacteria (1 × 10(8) to 2 × 10(8) airborne/m(3)), total number of S. suis bacteria (4 × 10(5) to 10 × 10(5) airborne/m(3)), and number of S. suis serotype 2 and 1/2 bacteria (1 × 10(3) to 30 × 10(3) airborne/m(3)) present in the air. S. suis serotypes 2 and 1/2 were detected in the air of all growing/finishing SCB that had documented cases of S. suis infection and in 50% of healthy SCB. The total number of bacteria and total numbers of S. suis and S. suis serotype 2 and 1/2 bacteria were monitored in one positive SCB during a 5-week period, and it was shown that the aerosolized S. suis serotypes 2 and 1/2 remain airborne for a prolonged period. When the effect of aerosolization on S. suis was observed, the percentage of intact S. suis bacteria (showing cell membrane integrity) in the air might have been up to 13%. Finally S. suis was found in nasal swabs from 14 out of 21 healthy finishing-SCB workers, suggesting significant exposure to the pathogen. This report provides a better understanding of the aerosolization, prevalence, and persistence of S. suis in SCB.

  3. Draft Genome Sequence of Hypervirulent and Vaccine Candidate Streptococcus suis Strain SC19

    PubMed Central

    Teng, Lin; Dong, Xingxing; Zhou, Yang; Li, Zhiwei; Deng, Limei; Chen, Huanchun; Wang, Xiaohong

    2017-01-01

    ABSTRACT Streptococcus suis, a zoonotic bacterium found primarily in pigs, has been recognized recently as an emerging pathogen of humans. Herein, we describe the genome of Streptococcus suis strain SC19, a hypervirulent and vaccine candidate strain isolated from a pig amid the 2005 outbreak in China. PMID:28104658

  4. Carbohydrate Availability Regulates Virulence Gene Expression in Streptococcus suis

    PubMed Central

    Ferrando, M. Laura; van Baarlen, Peter; Orrù, Germano; Piga, Rosaria; Bongers, Roger S.; Wels, Michiel; De Greeff, Astrid; Smith, Hilde E.; Wells, Jerry M.

    2014-01-01

    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 α-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 α-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. PMID:24642967

  5. Genetic analysis of Streptococcus suis isolates from wild rabbits.

    PubMed

    Sánchez del Rey, V; Fernández-Garayzábal, J F; Briones, V; Iriso, A; Domínguez, L; Gottschalk, M; Vela, A I

    2013-08-30

    This work aims to investigate the presence of Streptococcus suis in wild rabbits. A total of 65 S. suis isolates were recovered from 33.3% of the wild rabbits examined. Most isolates (86.2%) belong to genotype cps9. These isolates were further characterized by pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and virulence genotyping. Overall, S. suis exhibited a low genetic diversity. Only 5 genetic profiles were obtained by PFGE and most isolates (71.4%) were included in two pulsotypes that were also widely distributed among the wild rabbit population. MLST analysis assigned all cps9 isolates into three new singlestones (ST216, ST217 and ST284), which were not genetically related to the European ST87 and Spanish ST61 widespread swine clones, indicating a different genetic background for the S. suis isolates from wild rabbits and pigs. Wild rabbit isolates exhibited the genotype mrp-/epf-/sly-, different from those showed by most of the swine S. suis isolates of the ST87 and ST61 clones. None of the S. suis isolated from wild rabbits exhibited the genotype cps2/mrp+/epf+/sly+ associated with human infections. These results indicate that S. suis isolates from wild rabbits are not genetically related with prevalent clones usually associated with infections in pigs or humans in Europe and do not exhibit either their virulence genotypes. Therefore, although wild rabbits could represent an unknown reservoir of this pathogen, they could not represent a potential risk for pigs or humans.

  6. Vaccine development for protection against systemic infections with Streptococcus suis and Haemophilus parasuis in swine

    USDA-ARS?s Scientific Manuscript database

    Both Streptococcus suis and Haemophilus parasuis are important invasive bacterial pathogens of swine, commonly causing meningitis, arthritis, polyserositis, and septicemia. Due to the presence of many serotypes and high genotypic variability, efficacious vaccines are not readily available. We are us...

  7. A novel endolysin disrupts Streptococcus suis with high efficiency.

    PubMed

    Ji, Wenhui; Huang, Qingqing; Sun, Liang; Wang, Hengan; Yan, Yaxian; Sun, Jianhe

    2015-12-01

    Streptococcus suis serotype 2 (S. suis 2) is a zoonotic pathogen that exhibits high-level resistance and multi-drug resistance to classic antibiotics and causes serious human casualties and heavy economic losses in the swine industry worldwide. Therefore, alternative therapies or novel antibacterial agents need to be developed to combat this pathogen. A novel endolysin derived from the S. suis temperate phage phi7917, termed Ly7917, was identified, which had broad lytic activity against S. suis type 1, 2, 7 and 9. Ly7917 consisted of an N-terminal cysteine, histidine-dependent amidohydrolases/peptidase catalytic domain and C-terminal SH3b cell wall binding domain. The endolysin maintained activity at high pH and its catalytic activity could be improved by addition of 10 μM 1.5 mM Ca(2+). In animal studies, 90% of BALB/c mice challenged with typical virulent strain HA9801 of S. suis 2 were protected by Ly7917 treatment. The bacterial load in the blood of HA9801-challenged mice was efficiently reduced almost 50% by Ly7917 while that of penicillin-G-treated mice kept almost unchanged. Our data suggest that Ly7917 may be an alternative therapeutic agent for infections caused by virulent S. suis strains.

  8. Characterisation of Streptococcus suis isolates from wild boars (Sus scrofa).

    PubMed

    Sánchez del Rey, Verónica; Fernández-Garayzábal, José F; Mentaberre, Gregorio; Briones, Víctor; Lavín, Santiago; Domínguez, Lucas; Gottschalk, Marcelo; Vela, Ana Isabel

    2014-06-01

    Wild boar are widely distributed throughout the Iberian Peninsula and can carry potentially virulent strains of Streptococcus suis. The objective of this study was to determine the prevalence of S. suis in wild boars from two large geographical regions of Spain. Serotypes 1, 2, 7 and 9 identified were further genetically characterised by virulence-associated genotyping, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) to determine the population structure of S. suis carried by these animals. Streptococcus suis was isolated from 39.1% of the wild boars examined: serotype 9 was the most frequently isolated (12.5%), followed by serotype 1 (2.5%). Serotype 2 was rarely isolated (0.3%). Eighteen additional serotypes were identified indicating wide diversity of this pathogen within the wild boar population. This heterogeneity was confirmed by PFGE and MLST analyses and the majority of isolates exhibited the virulence-associated genotype mrp-/epf-/sly-. The results of this study highlight that the carriage of S. suis by wild boars is commonplace. However, MLST data indicate that these isolates are not related to prevalent clonal complexes ST1, ST16, ST61 and ST87 typically associated with infection of pigs or humans in Europe. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Establishment of a Cre recombinase based mutagenesis protocol for markerless gene deletion in Streptococcus suis.

    PubMed

    Koczula, A; Willenborg, J; Bertram, R; Takamatsu, D; Valentin-Weigand, P; Goethe, R

    2014-12-01

    The lack of knowledge about pathogenicity mechanisms of Streptococcus (S.) suis is, at least partially, attributed to limited methods for its genetic manipulation. Here, we established a Cre-lox based recombination system for markerless gene deletions in S. suis serotype 2 with high selective pressure and without undesired side effects. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Effects of Suilysin on Streptococcus suis-Induced Platelet Aggregation

    PubMed Central

    Zhang, Shengwei; Wang, Junping; Chen, Shaolong; Yin, Jiye; Pan, Zhiyuan; Liu, Keke; Li, Lin; Zheng, Yuling; Yuan, Yuan; Jiang, Yongqiang

    2016-01-01

    Blood platelets play important roles during pathological thrombocytopenia in streptococcal toxic shock syndrome (STSS). Streptococcus suis (S. suis) an emerging human pathogen, can cause STSS similarly to S. pyogenes. However, S. suis interactions with platelets are poorly understood. Here, we found that suilysin (SLY), different from other bacterial cholesterol-dependent cytolysins (CDCs), was the sole stimulus that induced platelet aggregation. Furthermore, the inside-out activation of GPIIb/IIIa of platelets mediated SLY-induced platelet aggregation. This process was triggered by Ca2+ influx that depend on the pore forming on platelets by SLY. Additionally, although SLY induced α-granule release occurred via the MLCK-dependent pathway, PLC-β-IP3/DAG-MLCK and Rho-ROCK-MLCK signaling were not involved in SLY-induced platelet aggregation. Interestingly, the pore dependent Ca2+ influx was also found to participate in the induction of platelet aggregation with pneumolysin (PLY) and streptolysin O (SLO), two other CDCs. It is possible that the CDC-mediated platelet aggregation we observed in S. suis is a similar response mechanism to that used by a wide range of bacteria. These findings might lead to the discovery of potential therapeutic targets for S. suis-associated STSS. PMID:27800304

  11. Streptococcus suis, an Important Cause of Adult Bacterial Meningitis in Northern Vietnam

    PubMed Central

    Wertheim, Heiman F. L.; Nguyen, Huyen Nguyen; Taylor, Walter; Lien, Trinh Thi Minh; Ngo, Hoa Thi; Nguyen, Thai Quoc; Nguyen, Bich Ngoc Thi; Nguyen, Ha Hong; Nguyen, Ha Minh; Nguyen, Cap Trung; Dao, Trinh Tuyet; Nguyen, Trung Vu; Fox, Annette; Farrar, Jeremy; Schultsz, Constance; Nguyen, Hien Duc; Nguyen, Kinh Van; Horby, Peter

    2009-01-01

    Background Streptococcus suis can cause severe systemic infection in adults exposed to infected pigs or after consumption of undercooked pig products. S. suis is often misdiagnosed, due to lack of awareness and improper testing. Here we report the first fifty cases diagnosed with S. suis infection in northern Viet Nam. Methodology/Principal Findings In 2007, diagnostics for S. suis were set up at a national hospital in Hanoi. That year there were 43 S. suis positive cerebrospinal fluid samples, of which S. suis could be cultured in 32 cases and 11 cases were only positive by PCR. Seven patients were blood culture positive for S. suis but CSF culture and PCR negative; making a total of 50 patients with laboratory confirmed S. suis infection in 2007. The number of S. suis cases peaked during the warmer months. Conclusions/Significance S. suis was commonly diagnosed as a cause of bacterial meningitis in adults in northern Viet Nam. In countries where there is intense and widespread exposure of humans to pigs, S. suis can be an important human pathogen. PMID:19543404

  12. Formate-tetrahydrofolate ligase is involved in the virulence of Streptococcus suis serotype 2.

    PubMed

    Zheng, Chengkun; Xu, Jiali; Shi, Guolin; Zhao, Xigong; Ren, Sujing; Li, Jinquan; Chen, Huanchun; Bei, Weicheng

    2016-09-01

    Streptococcus suis is an emerging zoonotic pathogen that causes severe infections in pigs and humans. However, the pathogenesis of S. suis remains unclear. The present study targeted a putative virulence-associated factor (fhs, encoding the formate-tetrahydrofolate ligase) of S. suis. To investigate the role of fhs in the virulence potential of S. suis serotype 2, an fhs deletion mutant (Δfhs) and the corresponding complementation strain (CΔfhs) were generated. The Δfhs mutant displayed similar growth compared to that of the wild-type and complementation strains. Using murine and pig infection models, we demonstrated for the first time that the formate-tetrahydrofolate ligase is required for the full virulence of S. suis 2. Our findings provide a new insight into the pathogenesis of S. suis 2.

  13. [Type 2 Streptococcus suis (R-Streptococci) as pathogens of occupational diseases. Report of a case and a review of the literature].

    PubMed

    Köhler, W; Queisser, H; Kunter, E; Sawitzki, R; Frach, G

    1989-03-01

    Report on the second human case of a Streptococcus suis type 2 (group R streptococci) infection in the GDR. The patient, a 33-year-old butcher, fell ill with an acute meningitis and an initial myocarditis. Group R streptococci were isolated from cerebrospinal fluid and blood. The patient was treated with penicillin G, ampicillin and gentamicin, followed by trimethoprim-sulfamerazine. Both, meningitis and myocarditis disappeared and the patient recovered completely. The disease was recognized as an occupational disease. Review of the literature. Since 1968 108 cases of human S.suis type 2 infections were described, mostly as meningitis. In most of the cases a close contact to pigs could be confirmed.

  14. Expression and immunological evaluation of elongation factor Tu of Streptococcus suis serotype 2.

    PubMed

    Xia, X J; Wang, L; Cheng, L K; Shen, Z Q; Li, S G; Wang, J L

    2017-03-01

    Streptococcus suis serotype 2 (SS2) is considered as a major pathogen that causes sepsis and meningitis in piglets and humans, but knowledge of its antigenic proteins remains limited so far. The surface-related proteins of pathogens often play significant roles in bacterium-host interactions and infection. Here, we obtained the elongation factor Tu (EF-Tu) gene of Streptococcus suis and constructed the recombinant expression plasmid successfully. The target recombinant plasmid was then expressed in Escherichia coli and the immuno-protection of the recombinant protein was subsequently evaluated as well. The EF-Tu gene of Streptococcus suis is 1197 bp in length, encodes 398 amino acids. The target recombinant EF-Tu (rEF-Tu) protein can recognize the antiserum of Streptococcus suis and can provoke obvious humoral immune responses in rabbits and conferred protection to rabbits against Streptococcus suis ear-vein challenge, implying that the EF-Tu may be used as an attractive candidate antigen for a component of subunit vaccine.

  15. Prophage lysin Ply30 protects mice from Streptococcus suis and Streptococcus equi subsp. zooepidemicus infections.

    PubMed

    Tang, Fang; Li, Dezhi; Wang, Haojin; Ma, Zhe; Lu, Chengping; Dai, Jianjun

    2015-11-01

    Streptococcus suis and Streptococcus equi subsp. zooepidemicus are capable of infecting humans and various animals, causing significant problems for the worldwide swine industry. As antibiotic resistance has increased, lysosomal enzymes encoded by phages have shown potential for use against pathogenic bacteria. In this study, a novel bacteriophage lysin, Ply30, encoded by the S. suis prophage phi30c, was recombinantly expressed and purified. Ply30 showed high bacteriolysis activity on S. suis and S. equi subsp. zooepidemicus in vitro. The ratio of the optical density at 600 nm (OD600) with treatment versus the OD600 with no treatment for most tested S. suis and S. equi subsp. zooepidemicus strains decreased from 1 to <0.3 and <0.5, respectively, within 1 h. The results of plate viability assays showed that treated bacteria suffered a 1- to 2-log decrease in CFU within 1 h. The optimal concentration of Ply30 was 50 μg/ml, and the optimal pH was 7. Moreover, Ply30 maintained high activity over a wide pH range (pH 6 to 10). The MICs of Ply30 against Streptococcus strains ranged from 16 to 512 μg/ml. In vivo, a 2-mg dose of Ply30 protected 90% (9/10 mice) of mice from infection with S. equi subsp. zooepidemicus and 80% (8/10 mice) of mice from infection with S. suis. Seven days after lysin Ply30 treatment, bacterial loads were significantly decreased in all tested organs and blood compared with those at 1 h postinfection without Ply30 treatment. Ply30 showed in vitro and in vivo antimicrobial efficiency and protected mice against two kinds of bacterial infections, indicating that Ply30 may be an effective therapeutic against streptococci. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. Isolation of Streptococcus suis from 2 lambs with a history of lameness

    PubMed Central

    Muckle, Anne; López, Alfonso; Gottschalk, Marcelo; López-Méndez, Carlos; Giles, Jan; Lund, Lorraine; Saab, Matthew

    2014-01-01

    Streptococcus suis was isolated postmortem from 2 lambs with a history of lameness. Identity of S. suis was confirmed by species-specific polymerase chain reaction (PCR) and by 16S rRNA gene sequencing. One isolate was untypable by serotyping and non-encapsulated, while the other isolate was serotype 33. The lambs had come from the same farm, and there was no evidence of contact between the lambs and pigs. Although the natural niche for S. suis is considered to be the pig, a wide range of host species may be affected by this pathogen. PMID:25320381

  17. Isolation of Streptococcus suis from 2 lambs with a history of lameness.

    PubMed

    Muckle, Anne; López, Alfonso; Gottschalk, Marcelo; López-Méndez, Carlos; Giles, Jan; Lund, Lorraine; Saab, Matthew

    2014-10-01

    Streptococcus suis was isolated postmortem from 2 lambs with a history of lameness. Identity of S. suis was confirmed by species-specific polymerase chain reaction (PCR) and by 16S rRNA gene sequencing. One isolate was untypable by serotyping and non-encapsulated, while the other isolate was serotype 33. The lambs had come from the same farm, and there was no evidence of contact between the lambs and pigs. Although the natural niche for S. suis is considered to be the pig, a wide range of host species may be affected by this pathogen.

  18. FATAL CASE OF STREPTOCOCCUS SUIS INFECTION IN A YOUNG WILD BOAR (SUS SCROFA) FROM SOUTHWESTERN SPAIN.

    PubMed

    Risco, David; Fernández-Llario, Pedro; Cuesta, Jesús M; García-Jiménez, Waldo L; Gonçalves, Pilar; Martínez, Remigio; García, Alfredo; Rosales, Rubén; Gómez, Luis; de Mendoza, Javier Hermoso

    2015-06-01

    Streptococcus suis is a recognized pathogen that may cause important diseases in pigs and humans. This microorganism has been repeatedly isolated from wild boar (Sus scrofa). However, its health implications for this wild species are still unknown. This article reports a detailed description of a fatal case of septicemia by S. suis affecting a young wild boar. The affected animal, about 15 days old, was found near death and exhibiting neurologic signs at a wild boar estate in southwestern Spain. Postmortem examination showed generalized congestion, brain hemorrhages and lobular pneumonia. Histopathological evaluation demonstrated the presence of meningitis and encephalitis with marked congestion and suppurative bronchopneumonia. Streptococcus suis serotype 2 isolates exhibiting important virulence factors (extracellular factor, muramidase-released protein, and suylisin) were isolated from the affected animal. This study confirms the presence of potentially virulent and zoonotic strains of S. suis in wild boar from Spain.

  19. Impact of serotype and sequence type on the preferential aerosolization of Streptococcus suis.

    PubMed

    Gauthier-Levesque, Léa; Bonifait, Laetitia; Turgeon, Nathalie; Veillette, Marc; Perrott, Phillipa; Grenier, Daniel; Duchaine, Caroline

    2016-05-14

    Streptococcus suis is a swine pathogen that causes pneumonia, septicemia and meningitis. It is also an important zoonotic agent responsible of several outbreaks in China. S. suis strains are classified into 35 serotypes based on the composition of their polysaccharide capsule. S. suis serotype 2 causes the majority of severe infections in pigs and in human, and can be further subdivided into sequence types (STs) based on multilocus sequence typing. The ST1 is associated with highly virulent strains. In North America, the strains most commonly isolated belong to ST25 and ST28, which are respectively moderately and weakly virulent in a mouse model. The presence of S. suis bioaerosols in the air of swine confinement buildings has been previously demonstrated. The aim of this study was to better understand the aerosolization behaviour of S. suis by investigating the preferential aerosolization of various strains of S. suis, belonging to different serotypes or STs, using in-house developed environmental chamber and bubble-burst nebulizer. qPCR technology was used to analyze the ratio of S. suis strains. The results suggest that the highly virulent serotype 2 ST1 strains are preferentially aerosolized and that the S. suis preferential aerosolization is a strain-dependent process. These observations will need to be confirmed using a larger number of strains. This study is a proof of concept and increases our knowledge on the potential aerosol transmission of S. suis.

  20. Draft genome sequences of nine Streptococcus suis strains isolated in the United States

    USDA-ARS?s Scientific Manuscript database

    Streptococcus suis is a swine pathogen responsible for economic losses to the pig industry worldwide. Additionally, it is a zoonotic agent that can cause severe infections in those in close contact with infected pigs and/or who consume uncooked or undercooked pork products. Here, we report nine draf...

  1. Effect of Licochalcone A on Growth and Properties of Streptococcus suis

    PubMed Central

    Liu, Peng; Lv, Qingyu; Zeng, Xiaotao; jiang, Hua; Wang, Yanzi; Zheng, Xin; Zheng, Yuling; Li, Jianchun; Zhou, Xuyu; Jiang, Yongqiang

    2013-01-01

    Streptococcus suis (S.suis) is an important emerging worldwide pig pathogen and zoonotic agent with rapid evolution of virulence and drug resistance. In this study, we wanted to investigate the effect of licochalcone A on growth and properties of Streptococcus suis. The antimicrobial activity of licochalcone A was tested by growth inhibition assay and the minimal inhibitory concentrations (MICs) also were determined. The effect of licochalcone A on S.suis biofilm formation was characterized by crystal violet staining. The effect of licochalcone A on suilysin secretion was evaluated by titration of hemolytic activity. To understand the antimicrobial effect, gene expression profile of S.suis treated by licochalcone A was analyzed by DNA microarray. Our results demonstrated that licochalcone A showed antimicrobial activity on S.suis with MICs of 4 µg/ml for S.suis serotype 2 strains and 8 µg/ml for S.suis serotype 7 strains. Biofilm formation was inhibited by 30–40% in the presence of licochalcone A (3 µg/ml) and suilysin secretion was also significantly inhibited in the presence of licochalcone A (1.5 µg/ml). The gene expression profile of S.suis in the presence of licochalcone A showed that 132 genes were differentially regulated, and we analyzed the regulated genes in the aspect of the bacterial cell cycle control. Among the deregulated genes, the genes responsible for the mass doubling was increased expression, but the genes responsible for DNA replication and cell division were inhibited the expression. So, we think the regulation of the cell cycle genes might provide a mechanistic understanding of licochalcone A mediated antimicrobial effect against S.suis. PMID:23935843

  2. Suicin 3908, a new lantibiotic produced by a strain of Streptococcus suis serotype 2 isolated from a healthy carrier pig.

    PubMed

    Vaillancourt, Katy; LeBel, Geneviève; Frenette, Michel; Gottschalk, Marcelo; Grenier, Daniel

    2015-01-01

    While Streptococcus suis serotype 2 is known to cause severe infections in pigs, it can also be isolated from the tonsils of healthy animals that do not develop infections. We hypothesized that S. suis strains in healthy carrier pigs may have the ability to produce bacteriocins, which may contribute to preventing infections by pathogenic S. suis strains. Two of ten S. suis serotype 2 strains isolated from healthy carrier pigs exhibited antibacterial activity against pathogenic S. suis isolates. The bacteriocin produced by S. suis 3908 was purified to homogeneity using a three-step procedure: ammonium sulfate precipitation, cationic exchange HPLC, and reversed-phase HPLC. The bacteriocin, called suicin 3908, had a low molecular mass; was resistant to heat, pH, and protease treatments; and possessed membrane permeabilization activity. Additive effects were obtained when suicin 3908 was used in combination with penicillin G or amoxicillin. The amino acid sequence of suicin 3908 suggested that it is lantibiotic-related and made it possible to identify a bacteriocin locus in the genome of S. suis D12. The putative gene cluster involved in suicin production by S. suis 3908 was amplified by PCR, and the sequence analysis revealed the presence of nine open reading frames (ORFs), including the structural gene and those required for the modification of amino acids, export, regulation, and immunity. Suicin 3908, which is encoded by the suiA gene, exhibited approximately 50% identity with bovicin HJ50 (Streptococcus bovis), thermophilin 1277 (Streptococcus thermophilus), and macedovicin (Streptococcus macedonicus). Given that S. suis 3908 cannot cause infections in animal models, that it is susceptible to conventional antibiotics, and that it produces a bacteriocin with antibacterial activity against all pathogenic S. suis strains tested, it could potentially be used to prevent infections and to reduce antibiotic use by the swine industry.

  3. Suicin 3908, a New Lantibiotic Produced by a Strain of Streptococcus suis Serotype 2 Isolated from a Healthy Carrier Pig

    PubMed Central

    Vaillancourt, Katy; LeBel, Geneviève; Frenette, Michel; Gottschalk, Marcelo; Grenier, Daniel

    2015-01-01

    While Streptococcus suis serotype 2 is known to cause severe infections in pigs, it can also be isolated from the tonsils of healthy animals that do not develop infections. We hypothesized that S. suis strains in healthy carrier pigs may have the ability to produce bacteriocins, which may contribute to preventing infections by pathogenic S. suis strains. Two of ten S. suis serotype 2 strains isolated from healthy carrier pigs exhibited antibacterial activity against pathogenic S. suis isolates. The bacteriocin produced by S. suis 3908 was purified to homogeneity using a three-step procedure: ammonium sulfate precipitation, cationic exchange HPLC, and reversed-phase HPLC. The bacteriocin, called suicin 3908, had a low molecular mass; was resistant to heat, pH, and protease treatments; and possessed membrane permeabilization activity. Additive effects were obtained when suicin 3908 was used in combination with penicillin G or amoxicillin. The amino acid sequence of suicin 3908 suggested that it is lantibiotic-related and made it possible to identify a bacteriocin locus in the genome of S. suis D12. The putative gene cluster involved in suicin production by S. suis 3908 was amplified by PCR, and the sequence analysis revealed the presence of nine open reading frames (ORFs), including the structural gene and those required for the modification of amino acids, export, regulation, and immunity. Suicin 3908, which is encoded by the suiA gene, exhibited approximately 50% identity with bovicin HJ50 (Streptococcus bovis), thermophilin 1277 (Streptococcus thermophilus), and macedovicin (Streptococcus macedonicus). Given that S. suis 3908 cannot cause infections in animal models, that it is susceptible to conventional antibiotics, and that it produces a bacteriocin with antibacterial activity against all pathogenic S. suis strains tested, it could potentially be used to prevent infections and to reduce antibiotic use by the swine industry. PMID:25659110

  4. Streptococcus suis Sequence Type 7 Outbreak, Sichuan, China

    PubMed Central

    Ye, Changyun; Zhu, Xiaoping; Jing, Huaiqi; Du, Huamao; Segura, Mariela; Zheng, Han; Kan, Biao; Wang, Lili; Bai, Xuemei; Zhou, Yongyun; Cui, Zhigang; Zhang, Shouying; Jin, Dong; Sun, Na; Luo, Xia; Zhang, Ji; Gong, Zhaolong; Wang, Xin; Wang, Lei; Sun, Hui; Li, Zhenjun; Sun, Qiangzheng; Liu, Honglu; Dong, Boqing; Ke, Changwen; Yuan, Hui; Wang, Hua; Tian, Kecheng; Wang, Yu; Gottschalk, Marcelo

    2006-01-01

    An outbreak of Streptococcus suis serotype 2 emerged in the summer of 2005 in Sichuan Province, and sporadic infections occurred in 4 additional provinces of China. In total, 99 S. suis strains were isolated and analyzed in this study: 88 isolates from human patients and 11 from diseased pigs. We defined 98 of 99 isolates as pulse type I by using pulsed-field gel electrophoresis analysis of SmaI-digested chromosomal DNA. Furthermore, multilocus sequence typing classified 97 of 98 members of the pulse type I in the same sequence type (ST), ST-7. Isolates of ST-7 were more toxic to peripheral blood mononuclear cells than ST-1 strains. S. suis ST-7, the causative agent, was a single-locus variant of ST-1 with increased virulence. These findings strongly suggest that ST-7 is an emerging, highly virulent S. suis clone that caused the largest S. suis outbreak ever described. PMID:16965698

  5. The Phage Lysin PlySs2 Decolonizes Streptococcus suis from Murine Intranasal Mucosa

    PubMed Central

    Gilmer, Daniel B.; Schmitz, Jonathan E.; Thandar, Mya; Euler, Chad W.; Fischetti, Vincent A.

    2017-01-01

    Streptococcus suis infects pigs worldwide and may be zoonotically transmitted to humans with a mortality rate of up to 20%. S. suis has been shown to develop in vitro resistance to the two leading drugs of choice, penicillin and gentamicin. Because of this, we have pursued an alternative therapy to treat these pathogens using bacteriophage lysins. The bacteriophage lysin PlySs2 is derived from an S. suis phage and displays potent lytic activity against most strains of that species including serotypes 2 and 9. At 64 μg/ml, PlySs2 reduced multiple serotypes of S. suis by 5 to 6-logs within 1 hour in vitro and exhibited a minimum inhibitory concentration (MIC) of 32 μg/ml for a S. suis serotype 2 strain and 64 μg/ml for a serotype 9 strain. Using a single 0.1-mg dose, the colonizing S. suis serotype 9 strain was reduced from the murine intranasal mucosa by >4 logs; a 0.1-mg dose of gentamicin reduced S. suis by <3-logs. A combination of 0.05 mg PlySs2 + 0.05 mg gentamicin reduced S. suis by >5-logs. While resistance to gentamicin was induced after systematically increasing levels of gentamicin in an S. suis culture, the same protocol resulted in no observable resistance to PlySs2. Thus, PlySs2 has both broad and high killing activity against multiple serotypes and strains of S. suis, making it a possible tool in the control and prevention of S. suis infections in pigs and humans. PMID:28046082

  6. Real-time PCR for detection of Streptococcus suis serotype 2 in cerebrospinal fluid of human patients with meningitis

    PubMed Central

    Nga, Tran Vu Thieu; Nghia, Ho Dang Trung; Tu, Le Thi Phuong; Diep, To Song; Mai, Nguyen Thi Hoang; Chau, Tran Thi Hong; Sinh, Dinh Xuan; Phu, Nguyen Hoan; Nga, Tran Thi Thu; Chau, Nguyen Van Vinh; Campbell, James; Hoa, Ngo Thi; Chinh, Nguyen Tran; Hien, Tran Tinh; Farrar, Jeremy; Schultsz, Constance

    2011-01-01

    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%) were culture positive. Culture-negative but PCR-positive CSF samples were significantly associated with the use of antimicrobial agents before admission. S. suis serotype 2 infection was more common than infections with Streptococcus pneumoniae and Neisseria meningitidis combined. Our results strikingly illustrate the additional diagnostic value of PCR in patients who are pretreated with antimicrobial agents and demonstrate the extremely high prevalence of S. suis infections among Vietnamese adult patients with bacterial meningitis. PMID:21767702

  7. Sub-MIC Tylosin Inhibits Streptococcus suis Biofilm Formation and Results in Differential Protein Expression

    PubMed Central

    Wang, Shuai; Yang, Yanbei; Zhao, Yulin; Zhao, Honghai; Bai, Jingwen; Chen, Jianqing; Zhou, Yonghui; Wang, Chang; Li, Yanhua

    2016-01-01

    Streptococcus suis (S.suis) is an important zoonotic pathogen that causes severe diseases in humans and pigs. Biofilms of S. suis can induce persistent infections that are difficult to treat. In this study, the effect of tylosin on biofilm formation of S. suis was investigated. 1/2 minimal inhibitory concentration (MIC) and 1/4 MIC of tylosin were shown to inhibit S. suis biofilm formation in vitro. By using the iTRAQ strategy, we compared the protein expression profiles of S. suis grown with sub-MIC tylosin treatment and with no treatment. A total of 1501 proteins were identified by iTRAQ. Ninety-six differentially expressed proteins were identified (Ratio > ±1.5, p < 0.05). Several metabolism proteins (such as phosphoglycerate kinase) and surface proteins (such as ABC transporter proteins) were found to be involved in biofilm formation. Our results indicated that S. suis metabolic regulation, cell surface proteins, and virulence proteins appear to be of importance in biofilm growth with sub-MIC tylosin treatment. Thus, our data revealed the rough regulation of biofilm formation that may provide a foundation for future research into mechanisms and targets. PMID:27065957

  8. Sub-MIC Tylosin Inhibits Streptococcus suis Biofilm Formation and Results in Differential Protein Expression.

    PubMed

    Wang, Shuai; Yang, Yanbei; Zhao, Yulin; Zhao, Honghai; Bai, Jingwen; Chen, Jianqing; Zhou, Yonghui; Wang, Chang; Li, Yanhua

    2016-01-01

    Streptococcus suis (S.suis) is an important zoonotic pathogen that causes severe diseases in humans and pigs. Biofilms of S. suis can induce persistent infections that are difficult to treat. In this study, the effect of tylosin on biofilm formation of S. suis was investigated. 1/2 minimal inhibitory concentration (MIC) and 1/4 MIC of tylosin were shown to inhibit S. suis biofilm formation in vitro. By using the iTRAQ strategy, we compared the protein expression profiles of S. suis grown with sub-MIC tylosin treatment and with no treatment. A total of 1501 proteins were identified by iTRAQ. Ninety-six differentially expressed proteins were identified (Ratio > ±1.5, p < 0.05). Several metabolism proteins (such as phosphoglycerate kinase) and surface proteins (such as ABC transporter proteins) were found to be involved in biofilm formation. Our results indicated that S. suis metabolic regulation, cell surface proteins, and virulence proteins appear to be of importance in biofilm growth with sub-MIC tylosin treatment. Thus, our data revealed the rough regulation of biofilm formation that may provide a foundation for future research into mechanisms and targets.

  9. Emodin affects biofilm formation and expression of virulence factors in Streptococcus suis ATCC700794.

    PubMed

    Yang, Yan-Bei; Wang, Shuai; Wang, Chang; Huang, Quan-Yong; Bai, Jing-Wen; Chen, Jian-Qing; Chen, Xue-Ying; Li, Yan-Hua

    2015-12-01

    Streptococcus suis (S. suis) is a swine pathogen and also a zoonotic agent. In this study, the effects of subinhibitory concentrations (sub-MICs) of emodin on biofilm formation by S. suis ATCC700794 were evaluated. As quantified by crystal violet staining, biofilm formation by S. suis ATCC700794 was dose-dependently decreased after growth with 1/2 MIC, 1/4 MIC, or 1/8 MIC of emodin. By scanning electron microscopy, the structural architecture of the S. suis ATCC700794 biofilms was examined following growth in culture medium supplemented with 1/2 MIC, 1/4 MIC, 1/8 MIC, or 1/16 MIC of emodin. Scanning electron microscopy analysis revealed the potential effect of emodin on biofilm formation by S. suis ATCC700794. The expression of luxS gene and virulence genes in S. suis ATCC700794 was investigated by quantitative RT-PCR. It was found that sub-MICs of emodin significantly decreased the expression of gapdh, sly, fbps, ef, and luxS. However, it was found that sub-MICs of emodin significantly increased the expression of cps2J, mrp, and gdh. These findings showed that sub-MICs of emodin could cause the difference in the expression level of the virulence genes.

  10. Immune-responsiveness of CD4+ T cells during Streptococcus suis serotype 2 infection

    PubMed Central

    Lecours, Marie-Pier; Letendre, Corinne; Clarke, Damian; Lemire, Paul; Galbas, Tristan; Benoit-Biancamano, Marie-Odile; Thibodeau, Jacques; Gottschalk, Marcelo; Segura, Mariela

    2016-01-01

    The pathogenesis of Streptococcus suis infection, a major swine and human pathogen, is only partially understood and knowledge on the host adaptive immune response is critically scarce. Yet, S. suis virulence factors, particularly its capsular polysaccharide (CPS), enable this bacterium to modulate dendritic cell (DC) functions and potentially impair the immune response. This study aimed to evaluate modulation of T cell activation during S. suis infection and the role of DCs in this response. S. suis-stimulated total mouse splenocytes readily produced TNF-α, IL-6, IFN-γ, CCL3, CXCL9, and IL-10. Ex vivo and in vivo analyses revealed the involvement of CD4+ T cells and a Th1 response. Nevertheless, during S. suis infection, levels of the Th1-derived cytokines TNF-α and IFN-γ were very low. A transient splenic depletion of CD4+ T cells and a poor memory response were also observed. Moreover, CD4+ T cells secreted IL-10 and failed to up-regulate optimal levels of CD40L and CD69 in coculture with DCs. The CPS hampered release of several T cell-derived cytokines in vitro. Finally, a correlation was established between severe clinical signs of S. suis disease and impaired antibody responses. Altogether, these results suggest S. suis interferes with the adaptive immune response. PMID:27905502

  11. [Bilateral sensorineural hearing impairment due to Streptococcus suis meningitis 20 days after swine bite].

    PubMed

    Mori, Kousuke; Ishii, Nobuyuki; Mochizuki, Hitoshi; Taniguchi, Akitoshi; Shiomi, Kazutaka; Nakazato, Masamitsu

    2013-01-01

    Streptococcus suis (S. suis) is a zoonotic pathogen in pigs, which can be transmitted to humans by close contact. Meningitis is the most common clinical manifestations of S. suis infection and hearing impairment is a frequent complication. The risk of S. suis meningitis is higher in people who work in the swine industry. The patient was a 53-year-old woman working in the swine industry, who developed headache and fever 20 days after a swine bite. She was diagnosed as meningitis and S. suis was detected in the cerebrospinal fluid. We treated her with ceftriaxone, vancomycin, and dexamethasone, and signs of meningeal irritation diminished three days after admission. However, bilateral sensorineural hearing impairment occurred on the ninth day after admission. We added methylprednisolone (500 mg, 2 days) but moderate hearing impairment remained on the left. Antibiotic therapy should be considered for wounds of people involved in the swine industry for preventing S. suis infection.When S. suis meningitis occurs, symptoms of hearing impairment must be monitored carefully.

  12. Sialic acid-dependent interactions between influenza viruses and Streptococcus suis affect the infection of porcine tracheal cells.

    PubMed

    Wu, Nai-Huei; Meng, Fandan; Seitz, Maren; Valentin-Weigand, Peter; Herrler, Georg

    2015-09-01

    Bacterial co-infections are a major complication in influenza-virus-induced disease in both humans and animals. Either of the pathogens may induce a host response that affects the infection by the other pathogen. A unique feature in the co-infection by swine influenza viruses (SIV) and Streptococcus suis serotype 2 is the direct interaction between the two pathogens. It is mediated by the haemagglutinin of SIV that recognizes the α2,6-linked sialic acid present in the capsular polysaccharide of Streptococcus suis. In the present study, this interaction was demonstrated for SIV of both H1N1 and H3N2 subtypes as well as for human influenza viruses that recognize α2,6-linked sialic acid. Binding of SIV to Streptococcus suis resulted in co-sedimentation of virus with bacteria during low-speed centrifugation. Viruses bound to bacteria retained infectivity but induced only tiny plaques compared with control virus. Infection of porcine tracheal cells by SIV facilitated adherence of Streptococcus suis, which was evident by co-staining of bacterial and viral antigen. Sialic-acid-dependent binding of Streptococcus suis was already detectable after incubation for 30 min. By contrast, bacterial co-infection had a negative effect on the replication of SIV as indicated by lower virus titres in the supernatant and a delay in the kinetics of virus release.

  13. Population Structure and Antimicrobial Resistance Profiles of Streptococcus suis Serotype 2 Sequence Type 25 Strains

    PubMed Central

    Athey, Taryn B. T.; Teatero, Sarah; Takamatsu, Daisuke; Wasserscheid, Jessica; Dewar, Ken; Gottschalk, Marcelo; Fittipaldi, Nahuel

    2016-01-01

    Strains of serotype 2 Streptococcus suis are responsible for swine and human infections. Different serotype 2 genetic backgrounds have been defined using multilocus sequence typing (MLST). However, little is known about the genetic diversity within each MLST sequence type (ST). Here, we used whole-genome sequencing to test the hypothesis that S. suis serotype 2 strains of the ST25 lineage are genetically heterogeneous. We evaluated 51 serotype 2 ST25 S. suis strains isolated from diseased pigs and humans in Canada, the United States of America, and Thailand. Whole-genome sequencing revealed numerous large-scale rearrangements in the ST25 genome, compared to the genomes of ST1 and ST28 S. suis strains, which result, among other changes, in disruption of a pilus island locus. We report that recombination and lateral gene transfer contribute to ST25 genetic diversity. Phylogenetic analysis identified two main and distinct Thai and North American clades grouping most strains investigated. These clades also possessed distinct patterns of antimicrobial resistance genes, which correlated with acquisition of different integrative and conjugative elements (ICEs). Some of these ICEs were found to be integrated at a recombination hot spot, previously identified as the site of integration of the 89K pathogenicity island in serotype 2 ST7 S. suis strains. Our results highlight the limitations of MLST for phylogenetic analysis of S. suis, and the importance of lateral gene transfer and recombination as drivers of diversity in this swine pathogen and zoonotic agent. PMID:26954687

  14. Identification and characterization of the chromosomal yefM-yoeB toxin-antitoxin system of Streptococcus suis

    PubMed Central

    Zheng, Chengkun; Xu, Jiali; Ren, Sujing; Li, Jinquan; Xia, Miaomiao; Chen, Huanchun; Bei, Weicheng

    2015-01-01

    Toxin-antitoxin (TA) systems are widely prevalent in the genomes of bacteria and archaea. These modules have been identified in Escherichia coli and various other bacteria. However, their presence in the genome of Streptococcus suis, an important zoonotic pathogen, has received little attention. In this study, we describe the identification and characterization of a type II TA system, comprising the chromosomal yefM-yoeB locus of S. suis. The yefM-yoeB locus is present in the genome of most serotypes of S. suis. Overproduction of S. suis YoeB toxin inhibited the growth of E. coli, and the toxicity of S. suis YoeB could be alleviated by the antitoxin YefM from S. suis and Streptococcus pneumoniae, but not by E. coli YefM. More importantly, introduction of the S. suis yefM-yoeB system into E. coli could affect cell growth. In a murine infection model, deletion of the yefM-yoeB locus had no effect on the virulence of S. suis serotype 2. Collectively, our data suggested that the yefM-yoeB locus of S. suis is an active TA system without the involvement of virulence. PMID:26272287

  15. Characterization of multi-drug tolerant persister cells in Streptococcus suis

    PubMed Central

    2014-01-01

    Background Persister cells constitute a subpopulation of dormant cells within a microbial population which are genetically identical but phenotypically different to regular cells. Notably, persister cells show an elevated tolerance to antimicrobial agents. Thus, they are considered to represent a microbial ‘bet-hedging’ strategy and are of particular importance in pathogenic bacteria. Results We studied the ability of the zoonotic pathogen Streptococcus (S.) suis to form multi-drug tolerant variants and identified persister cells dependent on the initial bacterial growth phase. We observed lower numbers of persisters in exponential phase cultures than in stationary growth phase populations. S. suis persister cells showed a high tolerance to a variety of antibiotics, and the phenotype was not inherited as tested with four passages of S. suis populations. Furthermore, we provide evidence that the persister phenotype is related to expression of genes involved in general metabolic pathways since we found higher numbers of persister cells in a mutant strain defective in the catabolic arginine deiminase system as compared to its parental wild type strain. Finally, we observed persister cell formation also in other S. suis strains and pathogenic streptococcal species. Conclusions Taken together, this is the first study that reports multi-drug tolerant persister cells in the zoonotic pathogen S. suis. PMID:24885389

  16. Characterization of multi-drug tolerant persister cells in Streptococcus suis.

    PubMed

    Willenborg, Jörg; Willms, Daniela; Bertram, Ralph; Goethe, Ralph; Valentin-Weigand, Peter

    2014-05-12

    Persister cells constitute a subpopulation of dormant cells within a microbial population which are genetically identical but phenotypically different to regular cells. Notably, persister cells show an elevated tolerance to antimicrobial agents. Thus, they are considered to represent a microbial 'bet-hedging' strategy and are of particular importance in pathogenic bacteria. We studied the ability of the zoonotic pathogen Streptococcus (S.) suis to form multi-drug tolerant variants and identified persister cells dependent on the initial bacterial growth phase. We observed lower numbers of persisters in exponential phase cultures than in stationary growth phase populations. S. suis persister cells showed a high tolerance to a variety of antibiotics, and the phenotype was not inherited as tested with four passages of S. suis populations. Furthermore, we provide evidence that the persister phenotype is related to expression of genes involved in general metabolic pathways since we found higher numbers of persister cells in a mutant strain defective in the catabolic arginine deiminase system as compared to its parental wild type strain. Finally, we observed persister cell formation also in other S. suis strains and pathogenic streptococcal species. Taken together, this is the first study that reports multi-drug tolerant persister cells in the zoonotic pathogen S. suis.

  17. Understanding Streptococcus suis serotype 2 infection in pigs through a transcriptional approach

    PubMed Central

    2011-01-01

    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 (PBMC), brain and lung tissues to infection with S. suis 2 strain SC19 using the Affymetrix Porcine Genome Array. Results A total of 3,002 differentially expressed transcripts were identified in the three tissues, including 417 unique genes in brain, 210 in lung and 213 in PBMC. These genes showed differential expression (DE) patterns on analysis by visualization and integrated discovery (DAVID). The DE genes involved in the immune response included genes related to the inflammatory response (CD163), the innate immune response (TLR2, TLR4, MYD88, TIRAP), cell adhesion (CD34, SELE, SELL, SELP, ICAM-1, ICAM-2, VCAM-1), antigen processing and presentation (MHC protein complex) and angiogenesis (VEGF), together with genes encoding cytokines (interleukins). Five selected genes were validated by qRT-PCR analysis. Conclusions We studied the response to infection with S. suis 2 strain SC19 by microarray analysis. Our findings confirmed some genes identified in previous studies and discovered numerous additional genes that potentially function in S. suis 2 infections in vivo. This new information will form the foundation of future investigations into the pathogenesis of S. suis. PMID:21599948

  18. Streptococcus suis meningitis with bilateral sensorineural hearing loss.

    PubMed

    Huh, Hee Jae; Park, Kyoung-Jin; Jang, Ja-Hyun; Lee, Mina; Lee, Jang Ho; Ahn, Yoon Hee; Kang, Cheol-In; Ki, Chang-Seok; Lee, Nam Yong

    2011-07-01

    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 from cerebrospinal fluid (CSF) and blood cultures and showed gray-white colonies with α-hemolysis. S. suis was identified from CSF and blood cultures by using a Vitek 2 system (bioMérieux, France), API 20 STREP (bioMérieux), and performing 16S rRNA and tuf gene sequencing. Even after receiving antibiotic treatment, patients with S. suis infection frequently show complications such as hearing impairment and vestibular dysfunction. To the best of our knowledge, this is the first case of S. suis meningitis in Korea. Prevention through public health surveillance is recommended, especially for individuals who have occupational exposures to swine and raw pork.

  19. The CodY regulator is essential for virulence in Streptococcus suis serotype 2

    PubMed Central

    Feng, Liping; Zhu, Jiawen; Chang, Haitao; Gao, Xiaoping; Gao, Cheng; Wei, Xiaofeng; Yuan, Fangyan; Bei, Weicheng

    2016-01-01

    The main role of CodY, a global regulatory protein in most low G + C gram-positive bacteria, is in transcriptional repression. To study the functions of CodY in Streptococcus suis serotype 2 (S. suis 2), a mutant codY clone named ∆codY was constructed to explore the phenotypic variation between ∆codY and the wild-type strain. The result showed that the codY mutation significantly inhibited cell growth, adherence and invasion ability of S. suis 2 to HEp-2 cells. The codY mutation led to decreased binding of the pathogen to the host cells, easier clearance by RAW264.7 macrophages and decreased growth ability in fresh blood of Cavia porcellus. The codY mutation also attenuated the virulence of S. suis 2 in BALB/c mice. Morphological analysis revealed that the codY mutation decreased the thickness of the capsule of S. suis 2 and changed the surface structures analylized by SDS-PAGE. Finally, the codY mutation altered the expressions of many virulence related genes, including sialic acid synthesis genes, leading to a decreased sialic acid content in capsule. Overall, mutation of codY modulated bacterial virulence by affecting the growth and colonization of S. suis 2, and at least via regulating sialic acid synthesis and capsule thickness. PMID:26883762

  20. Case report: two human Streptococcus suis infections in Borneo, Sabah, Malaysia.

    PubMed

    Rajahram, Giri Shan; Hameed, Ahneez Abdul; Menon, Jayaram; William, Timothy; Tambyah, Paul Anantharajah; Yeo, Tsin Wen

    2017-03-04

    Streptococcus Suis (S.suis) is increasingly being recognised as a potentially preventable emerging zoonotic infection in humans with a global distribution. It is a major cause of meningitis especially among those in contact with pigs and has also been associated with a toxic shock syndrome. We report the first two human cases from Sabah, Borneo, Malaysia which expands the global reach of this important pathogen. Here, we illustrate their epidemiological risk factors, clinical presentation and resulting sequelae of both patients. The continued public health threat of zoonotic infections such as S.suis, highlights the need for accurate epidemiological surveillance, regulation of pig farming, slaughtering and continued advocacy of best practices for pork preparation and consumption.

  1. Antimicrobial susceptibility of Streptococcus suis isolated from clinically healthy swine in Brazil

    PubMed Central

    Soares, Taíssa Cook Siqueira; Paes, Antonio Carlos; Megid, Jane; Ribolla, Paulo Eduardo Martins; Paduan, Karina dos Santos; Gottschalk, Marcelo

    2014-01-01

    Streptococcus suis is an important pathogen in the swine industry. This study is the first to report on the antimicrobial susceptibility of S. suis isolated from clinically healthy pigs in Brazil; the fourth major pork producer in the world. The antimicrobial susceptibility of 260 strains was determined by disc diffusion method. Strains were commonly susceptible to ceftiofur, cephalexin, chloramphenicol, and florfenicol, with more than 80% of the strains being susceptible to these antimicrobials. A high frequency of resistance to some of the antimicrobial agents was demonstrated, with resistance being most common to sulfa-trimethoprim (100%), tetracycline (97.69%), clindamycin (84.61%), norfloxacin (76.92%), and ciprofloxacin (61.15%). A high percentage of multidrug resistant strains (99.61%) were also found. The results of this study indicate that ceftiofur, cephalexin, and florfenicol are the antimicrobials of choice for empirical control of the infections caused by S. suis. PMID:24688177

  2. Evaluation of a ceftiofur-washed whole cell Streptococcus suis bacterin in pigs

    PubMed Central

    2004-01-01

    Abstract The efficacy of currently available washed whole cell Streptococcus suis bacterins is generally poor. We developed and tested the efficacy of a novel ceftiofur-washed whole cell bacterin. Sixty-six, 2-week-old specific pathogen free (SPF) pigs were randomly divided into 5 groups. Three groups were vaccinated 28 and 14 d prior to challenge. The 3 ceftiofur-washed whole cell bacterins each contained 1 of 3 different adjuvants (Montanide ISA 25, Montanide ISA 50, and Saponin). Pigs exhibiting severe central nervous system disease or severe joint swelling and lameness were euthanized immediately and necropsied. All remaining pigs were necropsied at 14 d post inoculation. The ceftiofur-washed whole cell S. suis bacterin with Montanide ISA 50 adjuvant significantly (P < 0.05) reduced bacteremia, meningitis, pneumonia, and mortality associated with S. suis challenge. Further work on this novel approach to bacterin production is warranted. PMID:15352553

  3. Streptococcus suis infection in swine. A sixteen month study.

    PubMed Central

    Higgins, R; Gottschalk, M; Mittal, K R; Beaudoin, M

    1990-01-01

    A total of 349 isolates of Streptococcus suis retrieved from different tissues from diseased pigs were examined in this study. Only 48% of them could be categorized as one of serotypes 1 to 8 and 1/2. Among typable isolates, serotype 2 was the most prevalent (23%), followed by serotype 3 (10%). The majority of all isolates originated from lungs, meninges/brain, and multiple tissues. Forty-one percent of typable isolates and 33% of untypable isolates were retrieved in pure culture. Other isolates were found in conjunction with Pasteurella multocida, Escherichia coli, Actinobacillus pleuropneumoniae, Actinomyces pyogenes, and other streptococci. Typable S. suis isolates were more frequently isolated from pigs between five and ten weeks of age, while untypable isolates were mostly found in animals aged more than 24 weeks. No obvious monthly and/or seasonal variation of the prevalence of isolation of S. suis could be detected. PMID:2306668

  4. Transcriptomic Analysis Reveals Selective Metabolic Adaptation of Streptococcus suis to Porcine Blood and Cerebrospinal Fluid

    PubMed Central

    Koczula, Anna; Jarek, Michael; Visscher, Christian; Valentin-Weigand, Peter; Goethe, Ralph; Willenborg, Jörg

    2017-01-01

    Streptococcus suis is a zoonotic pathogen that can cause severe pathologies such as septicemia and meningitis in its natural porcine host as well as in humans. Establishment of disease requires not only virulence of the infecting strain but also an appropriate metabolic activity of the pathogen in its host environment. However, it is yet largely unknown how the streptococcal metabolism adapts to the different host niches encountered during infection. Our previous isotopologue profiling studies on S. suis grown in porcine blood and cerebrospinal fluid (CSF) revealed conserved activities of central carbon metabolism in both body fluids. On the other hand, they suggested differences in the de novo amino acid biosynthesis. This prompted us to further dissect S. suis adaptation to porcine blood and CSF by RNA deep sequencing (RNA-seq). In blood, the majority of differentially expressed genes were associated with transport of alternative carbohydrate sources and the carbohydrate metabolism (pentose phosphate pathway, glycogen metabolism). In CSF, predominantly genes involved in the biosynthesis of branched-chain and aromatic amino acids were differentially expressed. Especially, isoleucine biosynthesis seems to be of major importance for S. suis in CSF because several related biosynthetic genes were more highly expressed. In conclusion, our data revealed niche-specific metabolic gene activity which emphasizes a selective adaptation of S. suis to host environments. PMID:28212285

  5. Transcriptomic Analysis Reveals Selective Metabolic Adaptation of Streptococcus suis to Porcine Blood and Cerebrospinal Fluid.

    PubMed

    Koczula, Anna; Jarek, Michael; Visscher, Christian; Valentin-Weigand, Peter; Goethe, Ralph; Willenborg, Jörg

    2017-02-15

    Streptococcus suis is a zoonotic pathogen that can cause severe pathologies such as septicemia and meningitis in its natural porcine host as well as in humans. Establishment of disease requires not only virulence of the infecting strain but also an appropriate metabolic activity of the pathogen in its host environment. However, it is yet largely unknown how the streptococcal metabolism adapts to the different host niches encountered during infection. Our previous isotopologue profiling studies on S. suis grown in porcine blood and cerebrospinal fluid (CSF) revealed conserved activities of central carbon metabolism in both body fluids. On the other hand, they suggested differences in the de novo amino acid biosynthesis. This prompted us to further dissect S. suis adaptation to porcine blood and CSF by RNA deep sequencing (RNA-seq). In blood, the majority of differentially expressed genes were associated with transport of alternative carbohydrate sources and the carbohydrate metabolism (pentose phosphate pathway, glycogen metabolism). In CSF, predominantly genes involved in the biosynthesis of branched-chain and aromatic amino acids were differentially expressed. Especially, isoleucine biosynthesis seems to be of major importance for S. suis in CSF because several related biosynthetic genes were more highly expressed. In conclusion, our data revealed niche-specific metabolic gene activity which emphasizes a selective adaptation of S. suis to host environments.

  6. Identification and characterization of inosine 5-monophosphate dehydrogenase in Streptococcus suis type 2.

    PubMed

    Zhang, Xue-han; He, Kong-wang; Duan, Zhi-tao; Zhou, Jun-ming; Yu, Zheng-yu; Ni, Yan-xiu; Lu, Cheng-ping

    2009-11-01

    Streptococcus suis type 2 is a swine pathogen responsible for diverse diseases. Although many virulent factors have been identified and studied, relatively little is known about the pathogenic mechanisms of type 2. The aim of the study was to identify and understand the characterization of Inosine 5-monophosphate dehydrogenase (IMPDH). A 957-bp gene, impdh, was identified in the virulent S. suis serotype 2 (SS2), and analysis of the predicted IMPDH sequence revealed IMP dehydrogenase/GMP reductase domain. The gene encoding for the IMPDH of S. suis was cloned and sequenced. The DNA sequence contained an open reading frame encoding for a 318 amino acid polypeptide exhibiting 23% sequence identity with the IMPDH from Streptococcus pyogenes (YP281355) and Streptococcus pneumoniae (ZP00404150). Using the pET(32) expression plasmid, the impdh gene was inducibly overexpressed in Escherichia coli to produce IMPDH with a hexahistidyl N-terminus to permit its purification. The (His)6 IMPDH protein was found to possess functional IMPDH enzymatic activity after the purification. The impdh-knockout SS2 mutant ( Delta IMPDH) constructed in this study was slower in growth and one pH unit higher than SS2-H after 6 h of culturing, and found to be attenuated in mouse models of infection for 2.5 times and not be capable of causing death in porcine models of infection in contrast with the parent SS2-H.

  7. Role of Capsule and Suilysin in Mucosal Infection of Complement-Deficient Mice with Streptococcus suis

    PubMed Central

    Seitz, Maren; Beineke, Andreas; Singpiel, Alena; Willenborg, Jörg; Dutow, Pavel; Goethe, Ralph; Valentin-Weigand, Peter; Klos, Andreas

    2014-01-01

    Virulent Streptococcus suis serotype 2 strains are invasive extracellular bacteria causing septicemia and meningitis in piglets and humans. One objective of this study was to elucidate the function of complement in innate immune defense against S. suis. Experimental infection of wild-type (WT) and C3−/− mice demonstrated for the first time that the complement system protects naive mice against invasive mucosal S. suis infection. S. suis WT but not an unencapsulated mutant caused mortality associated with meningitis and other pathologies in C3−/− mice. The capsule contributed also substantially to colonization of the upper respiratory tract. Experimental infection of C3−/− mice with a suilysin mutant indicated that suilysin expression facilitated an early disease onset and the pathogenesis of meningitis. Flow cytometric analysis revealed C3 antigen deposition on the surface of ca. 40% of S. suis WT bacteria after opsonization with naive WT mouse serum, although to a significantly lower intensity than on the unencapsulated mutant. Ex vivo multiplication in murine WT and C3−/− blood depended on capsule but not suilysin expression. Interestingly, S. suis invasion of inner organs was also detectable in C5aR−/− mice, suggesting that chemotaxis and activation of immune cells via the anaphylatoxin receptor C5aR is, in addition to opsonization, a further important function of the complement system in defense against mucosal S. suis infection. In conclusion, we unequivocally demonstrate here the importance of complement against mucosal S. suis serotype 2 infection and that the capsule of this pathogen is also involved in escape from complement-independent immunity. PMID:24686060

  8. Role of capsule and suilysin in mucosal infection of complement-deficient mice with Streptococcus suis.

    PubMed

    Seitz, Maren; Beineke, Andreas; Singpiel, Alena; Willenborg, Jörg; Dutow, Pavel; Goethe, Ralph; Valentin-Weigand, Peter; Klos, Andreas; Baums, Christoph G

    2014-06-01

    Virulent Streptococcus suis serotype 2 strains are invasive extracellular bacteria causing septicemia and meningitis in piglets and humans. One objective of this study was to elucidate the function of complement in innate immune defense against S. suis. Experimental infection of wild-type (WT) and C3(-/-) mice demonstrated for the first time that the complement system protects naive mice against invasive mucosal S. suis infection. S. suis WT but not an unencapsulated mutant caused mortality associated with meningitis and other pathologies in C3(-/-) mice. The capsule contributed also substantially to colonization of the upper respiratory tract. Experimental infection of C3(-/-) mice with a suilysin mutant indicated that suilysin expression facilitated an early disease onset and the pathogenesis of meningitis. Flow cytometric analysis revealed C3 antigen deposition on the surface of ca. 40% of S. suis WT bacteria after opsonization with naive WT mouse serum, although to a significantly lower intensity than on the unencapsulated mutant. Ex vivo multiplication in murine WT and C3(-/-) blood depended on capsule but not suilysin expression. Interestingly, S. suis invasion of inner organs was also detectable in C5aR(-/-) mice, suggesting that chemotaxis and activation of immune cells via the anaphylatoxin receptor C5aR is, in addition to opsonization, a further important function of the complement system in defense against mucosal S. suis infection. In conclusion, we unequivocally demonstrate here the importance of complement against mucosal S. suis serotype 2 infection and that the capsule of this pathogen is also involved in escape from complement-independent immunity.

  9. First Report of the Multiresistance Gene cfr in Streptococcus suis

    PubMed Central

    Wang, Yang; Li, Dexi; Song, Li; Liu, Yang; He, Tao; Liu, Hebing; Wu, Congming

    2013-01-01

    The multiresistance gene cfr was identified for the first time in streptococci, namely, in porcine Streptococcus suis isolate S10. The cfr gene was detected on the ∼100-kb plasmid pStrcfr, where it was bracketed by two copies of the novel insertion sequence ISEnfa5, located in the same orientation. The detection of a cfr- and ISEnfa5-containing amplicon by inverse PCR suggests that ISEnfa5 may play a role in the dissemination of cfr. PMID:23733472

  10. Identification of a Novel Virulence Determinant with Serum Opacification Activity in Streptococcus suis

    PubMed Central

    Baums, Christoph G.; Kaim, Ute; Fulde, Marcus; Ramachandran, Girish; Goethe, Ralph; Valentin-Weigand, Peter

    2006-01-01

    Streptococcus suis serotype 2 is a porcine and human pathogen with adhesive and invasive properties. In other streptococci, large surface-associated proteins (>100 kDa) of the MSCRAMM family (microbial surface components recognizing adhesive matrix molecules) are key players in interactions with host tissue. In this study, we identified a novel opacity factor of S. suis (OFS) with structural homology to members of the MSCRAMM family. The N-terminal region of OFS is homologous to the respective regions of fibronectin-binding protein A (FnBA) of Streptococcus dysgalactiae and the serum opacity factor (SOF) of Streptococcus pyogenes. Similar to these two proteins, the N-terminal domain of OFS opacified horse serum. Serum opacification activity was detectable in sodium dodecyl sulfate extracts of wild-type S. suis but not in extracts of isogenic ofs knockout mutants. Heterologous expression of OFS in Lactococcus lactis demonstrated that a high level of expression of OFS is sufficient to provide surface-associated serum opacification activity. Furthermore, serum opacification could be inhibited by an antiserum against recombinant OFS. The C-terminal repetitive sequence elements of OFS differed significantly from the respective repeat regions of FnBA and SOF as well as from the consensus sequence of the fibronectin-binding repeats of MSCRAMMs. Accordingly, fibronectin binding was not detectable in recombinant OFS. To investigate the putative function of OFS in the pathogenesis of invasive S. suis diseases, piglets were experimentally infected with an isogenic mutant strain in which the ofs gene had been knocked out by an in-frame deletion. The mutant was severely attenuated in virulence but not in colonization, demonstrating that OFS represents a novel virulence determinant of S. suis. PMID:17057090

  11. Impact of a Food Safety Campaign on Streptococcus suis Infection in Humans in Thailand.

    PubMed

    Takeuchi, Dan; Kerdsin, Anusak; Akeda, Yukihiro; Chiranairadul, Piphat; Loetthong, Phacharaphan; Tanburawong, Nutchada; Areeratana, Prasanee; Puangmali, Panarat; Khamisara, Kasean; Pinyo, Wirasinee; Anukul, Rapeepun; Samerchea, Sutit; Lekhalula, Punpong; Nakayama, Tatsuya; Yamamoto, Kouji; Hirose, Masayo; Hamada, Shigeyuki; Dejsirilert, Surang; Oishi, Kazunori

    2017-06-01

    AbstractStreptococcus suis is an important zoonotic pathogen in swine and humans that causes sepsis and meningitis. Our previous study in Thailand showed that the prevalence of S. suis infection in humans, especially in northern areas of Thailand, and the transmission of the pathogen occurred mainly through the consumption of traditional raw pork products. Considering the high incidence proportion and mortality rate of the disease as an important public health problem, we implemented a food safety campaign in the Phayao Province in northern Thailand in 2011. We evaluated the effects of a food safety campaign by comparing the sociodemographic, clinical, and bacteriological characteristics of cases before and after the campaign. The follow-up study showed a marked decrease of the incidence proportion in the first 2 years, indicating the effectiveness of the campaign. In the third year, however, the incidence proportion slightly increased again, indicating the existence of deep-rooted cultural behaviors and the necessity of continuous public health intervention. Furthermore, epidemiological analysis of the cases made it possible to estimate the infectivity of the pathogen via the oral route of infection. In the present study, we showed the effectiveness of the food safety campaign for controlling the S. suis infection, and we present a role model public health intervention for prevalent areas affected by S. suis infection in humans.

  12. The pathogenesis of the meningitis caused by Streptococcus suis: the unresolved questions.

    PubMed

    Gottschalk, M; Segura, M

    2000-10-01

    Streptococcus suis is one of the most important swine pathogens world-wide. Among the serotypes described, type 2 is the serotype most frequently associated with disease. Despite increasing research in recent years, knowledge of virulence factors and the pathogenesis of the infection remain limited. This review discusses the currently available information on S. suis serotype 2 virulence factors and the pathogenesis of the meningitis caused by this important bacterial species. In addition, some hypotheses on the critical steps of the infection, such as bacterial invasion from mucosal surfaces to the bloodstream, survival of bacteria in blood, and invasion from blood into the central nervous system, are presented. Finally, the role that the stimulation of the immune system of animals (inflammatory reaction) could play during infection is also discussed. A complete understanding of the cell-interacting pathways that S. suis may follow inside the host could give important insights into the progression of disease. Further studies to delineate the mechanisms through which S. suis induces meningitis will contribute to the development of potential therapies for S. suis infections.

  13. A Locus Encoding Variable Defense Systems against Invading DNA Identified in Streptococcus suis

    PubMed Central

    Okura, Masatoshi; Nozawa, Takashi; Watanabe, Takayasu; Murase, Kazunori; Nakagawa, Ichiro; Takamatsu, Daisuke; Osaki, Makoto; Sekizaki, Tsutomu; Gottschalk, Marcelo; Hamada, Shigeyuki

    2017-01-01

    Streptococcus suis, an important zoonotic pathogen, is known to have an open pan-genome and to develop a competent state. In S. suis, limited genetic lineages are suggested to be associated with zoonosis. However, little is known about the evolution of diversified lineages and their respective phenotypic or ecological characteristics. In this study, we performed comparative genome analyses of S. suis, with a focus on the competence genes, mobile genetic elements, and genetic elements related to various defense systems against exogenous DNAs (defense elements) that are associated with gene gain/loss/exchange mediated by horizontal DNA movements and their restrictions. Our genome analyses revealed a conserved competence-inducing peptide type (pherotype) of the competence system and large-scale genome rearrangements in certain clusters based on the genome phylogeny of 58 S. suis strains. Moreover, the profiles of the defense elements were similar or identical to each other among the strains belonging to the same genomic clusters. Our findings suggest that these genetic characteristics of each cluster might exert specific effects on the phenotypic or ecological differences between the clusters. We also found certain loci that shift several types of defense elements in S. suis. Of note, one of these loci is a previously unrecognized variable region in bacteria, at which strains of distinct clusters code for different and various defense elements. This locus might represent a novel defense mechanism that has evolved through an arms race between bacteria and invading DNAs, mediated by mobile genetic elements and genetic competence. PMID:28379509

  14. Recruitment of Factor H to the Streptococcus suis Cell Surface is Multifactorial.

    PubMed

    Roy, David; Grenier, Daniel; Segura, Mariela; Mathieu-Denoncourt, Annabelle; Gottschalk, Marcelo

    2016-07-07

    Streptococcus suis is an important bacterial swine pathogen and a zoonotic agent. Recently, two surface proteins of S. suis, Fhb and Fhbp, have been described for their capacity to bind factor H-a soluble complement regulatory protein that protects host cells from complement-mediated damages. Results obtained in this study showed an important role of host factor H in the adhesion of S. suis to epithelial and endothelial cells. Both Fhb and Fhbp play, to a certain extent, a role in such increased factor H-dependent adhesion. The capsular polysaccharide (CPS) of S. suis, independently of the presence of its sialic acid moiety, was also shown to be involved in the recruitment of factor H. However, a triple mutant lacking Fhb, Fhbp and CPS was still able to recruit factor H resulting in the degradation of C3b in the presence of factor I. In the presence of complement factors, the double mutant lacking Fhb and Fhbp was similarly phagocytosed by human macrophages and killed by pig blood when compared to the wild-type strain. In conclusion, this study suggests that recruitment of factor H to the S. suis cell surface is multifactorial and redundant.

  15. Recruitment of Factor H to the Streptococcus suis Cell Surface is Multifactorial

    PubMed Central

    Roy, David; Grenier, Daniel; Segura, Mariela; Mathieu-Denoncourt, Annabelle; Gottschalk, Marcelo

    2016-01-01

    Streptococcus suis is an important bacterial swine pathogen and a zoonotic agent. Recently, two surface proteins of S. suis, Fhb and Fhbp, have been described for their capacity to bind factor H—a soluble complement regulatory protein that protects host cells from complement-mediated damages. Results obtained in this study showed an important role of host factor H in the adhesion of S. suis to epithelial and endothelial cells. Both Fhb and Fhbp play, to a certain extent, a role in such increased factor H-dependent adhesion. The capsular polysaccharide (CPS) of S. suis, independently of the presence of its sialic acid moiety, was also shown to be involved in the recruitment of factor H. However, a triple mutant lacking Fhb, Fhbp and CPS was still able to recruit factor H resulting in the degradation of C3b in the presence of factor I. In the presence of complement factors, the double mutant lacking Fhb and Fhbp was similarly phagocytosed by human macrophages and killed by pig blood when compared to the wild-type strain. In conclusion, this study suggests that recruitment of factor H to the S. suis cell surface is multifactorial and redundant. PMID:27399785

  16. Streptococcus suis outbreak investigation using multiple-locus variable tandem repeat number analysis.

    PubMed

    Li, Wei; Ye, Changyun; Jing, Huaiqi; Cui, Zhigang; Bai, Xuemei; Jin, Dong; Zheng, Han; Zhao, Ailan; Xu, Yanmei; Gottschalk, Marcelo; Xu, Jianguo

    2010-07-01

    Two outbreaks of Streptococcus suis ST7 occurred in humans in 1998 and 2005 in China. PFGE of chromosome restriction fragments found all ST7 isolates to be indistinguishable. Due to the genetic homogeneity of ST7 isolates, development of a rapid sub-typing method with high discriminatory power for ST7 isolates is required. In this study, a novel method, MLVA, was developed to type S. suis serotype 2 strains. Further, this method was used to analyze outbreak-associated ST7 strains in China. A total of 144 ST7 S. suis isolates were sub-typed into 34 MLVA types. Among these, eight isolates from the 1998 outbreak were sub-typed into five MLVA types, of which four MLVA types were also detected in Sichuan in 2005. These data indicate that the pathogens responsible for the two outbreaks had the same origin. In addition, some observations also provided molecular evidence for the transmission route, possibly indicating that the MLVA method has usefulness in epidemiology. The developed MLVA scheme for S. suis has greater discriminative power than PFGE. The method described here may be useful for identifying the source of S. suis infection and monitoring its spread.

  17. Reappraisal of the taxonomy of Streptococcus suis serotypes 20, 22 and 26: Streptococcus parasuis sp. nov.

    PubMed

    Nomoto, R; Maruyama, F; Ishida, S; Tohya, M; Sekizaki, T; Osawa, Ro

    2015-02-01

    In order to clarify the taxonomic position of serotypes 20, 22 and 26 of Streptococcus suis, biochemical and molecular genetic studies were performed on isolates (SUT-7, SUT-286(T), SUT-319, SUT-328 and SUT-380) reacted with specific antisera of serotypes 20, 22 or 26 from the saliva of healthy pigs as well as reference strains of serotypes 20, 22 and 26. Comparative recN gene sequencing showed high genetic relatedness among our isolates, but marked differences from the type strain S. suis NCTC 10234(T), i.e. 74.8-75.7 % sequence similarity. The genomic relatedness between the isolates and other strains of species of the genus Streptococcus, including S. suis, was calculated using the average nucleotide identity values of whole genome sequences, which indicated that serotypes 20, 22 and 26 should be removed taxonomically from S. suis and treated as a novel genomic species. Comparative sequence analysis revealed 99.0-100 % sequence similarities for the 16S rRNA genes between the reference strains of serotypes 20, 22 and 26, and our isolates. Isolate STU-286(T) had relatively high 16S rRNA gene sequence similarity with S. suis NCTC 10234(T) (98.8 %). SUT-286(T) could be distinguished from S. suis and other closely related species of the genus Streptococcus using biochemical tests. Due to its phylogenetic and phenotypic similarities to S. suis we propose naming the novel species Streptococcus parasuis sp. nov., with SUT-286(T) ( = JCM 30273(T) = DSM 29126(T)) as the type strain.

  18. Streptococcus suis Meningitis: A Systematic Review and Meta-analysis

    PubMed Central

    van Samkar, Anusha; Brouwer, Matthijs C.; Schultsz, Constance; van der Ende, Arie; van de Beek, Diederik

    2015-01-01

    Background Streptococcus suis is the most common cause of meningitis in pork consuming and pig rearing countries in South-East Asia. We performed a systematic review of studies on S. suis meningitis to define the clinical characteristics, predisposing factors and outcome. Methodology Studies published between January 1, 1980 and August 1, 2015 were identified from main literature databases and reference lists. Studies were included if they were written in West-European languages and described at least 5 adult patients with S. suis meningitis in whom at least one clinical characteristic was described. Findings We identified 913 patients with S. suis meningitis included in 24 studies between 1980 and 2015. The mean age was 49 years and 581 of 711 patients were male (82%). Exposure to pigs or pork was present in 395 of 648 patients (61%) while other predisposing factors were less common. 514 of 528 patients presented with fever (97%), 429 of 451 with headache (95%), 462 of 496 with neck stiffness (93%) and 78 of 384 patients (20%) had a skin injury in the presence of pig/pork contact. The case fatality rate was 2.9% and hearing loss was a common sequel occurring in 259 of 489 patients (53%). Treatment included dexamethasone in 157 of 300 (52%) of patients and was associated with reduced hearing loss in S. suis meningitis patients included in a randomized controlled trial. Conclusion S. suis meningitis has a clear association with pig and pork contact. Mortality is low, but hearing loss occurs frequently. Dexamethasone was shown to reduce hearing loss. PMID:26505485

  19. Genetic diversity of Streptococcus suis isolates as determined by comparative genome hybridization

    PubMed Central

    2011-01-01

    Background 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. Results In this study, the correlation between gene content, serotype, phenotype and virulence among 55 S. suis strains was studied using Comparative Genome Hybridization (CGH). Clustering of CGH data divided S. suis isolates into two clusters, A and B. Cluster A isolates could be discriminated from cluster B isolates based on the protein expression of extracellular factor (EF). Cluster A contained serotype 1 and 2 isolates that were correlated with virulence. Cluster B mainly contained serotype 7 and 9 isolates. Genetic similarity was observed between serotype 7 and serotype 2 isolates that do not express muramidase released protein (MRP) and EF (MRP-EF-), suggesting these isolates originated from a common founder. Profiles of 25 putative virulence-associated genes of S. suis were determined among the 55 isolates. Presence of all 25 genes was shown for cluster A isolates, whereas cluster B isolates lacked one or more putative virulence genes. Divergence of S. suis isolates was further studied based on the presence of 39 regions of difference. Conservation of genes was evaluated by the definition of a core genome that contained 78% of all ORFs in P1/7. Conclusions In conclusion, we show that CGH is a valuable method to study distribution of genes or gene clusters among isolates in detail, yielding information on genetic similarity, and virulence traits of S. suis isolates. PMID:21736719

  20. Identification of a Novel Host-Specific IgM Protease in Streptococcus suis

    PubMed Central

    Seele, Jana; Singpiel, Alena; Spoerry, Christian; von Pawel-Rammingen, Ulrich; Valentin-Weigand, Peter

    2013-01-01

    Streptococcus suis serotype 2 is a highly invasive, extracellular pathogen in pigs with the capacity to cause severe infections in humans. This study was initiated by the finding that IgM degradation products are released after opsonization of S. suis. The objective of this work was to identify the bacterial factor responsible for IgM degradation. The results of this study showed that a member of the IdeS family, designated IdeSsuis (Immunoglobulin M-degrading enzyme of S. suis), is responsible and sufficient for IgM cleavage. Recombinant IdeSsuis was found to degrade only IgM but neither IgG nor IgA. Interestingly, Western blot analysis revealed that IdeSsuis is host specific, as it exclusively cleaves porcine IgM but not IgM from six other species, including a closely related member of the Suidae family. As demonstrated by flow cytometry and immunofluorescence microscopy, IdeSsuis modulates binding of IgM to the bacterial surface. IdeSsuis is the first prokaryotic IgM-specific protease described, indicating that this enzyme is involved in a so-far-unknown mechanism of host-pathogen interaction at an early stage of the host immune response. Furthermore, cleavage of porcine IgM by IdeSsuis is the first identified phenotype reflecting functional adaptation of S. suis to pigs as the main host. PMID:23243300

  1. Characteristics of Streptococcus suis isolated from patients in Japan.

    PubMed

    Chang, Bin; Wada, Akihito; Ikebe, Tadayoshi; Ohnishi, Makoto; Mita, Kazuhito; Endo, Miyoko; Matsuo, Hirosuke; Asatuma, Yoshinori; Kuramoto, Sanae; Sekiguchi, Hiroshi; Yamazaki, Motoyosi; Yoshikawa, Hiroko; Watabe, Nobuei; Yamada, Hideko; Kurita, Shohachi; Imai, Yumiko; Watanabe, Haruo

    2006-12-01

    Seven cases of Streptococcus suis infection in Japan during 1994 and 2006 were summarized. All cases had porcine exposure and five of them had hand skin injury during the exposure. Five cases presented symptoms of meningitis, three presented symptoms of sepsis, and one resulted in sudden death. All of the isolated S. suis belonged to Lancefield's group D and to serotype 2. They were susceptible to penicillin G, ampicillin, cefotaxime, and ciprofloxacin. However, six of them were resistant to both erythromycin and clindamycin, and four were also resistant to minocycline. Multilocus sequence typing of six isolates showed that they belonged to sequence type (ST) 1, and their pulsed-field gel electrophoresis (PFGE) patterns were similar. The remaining isolate was ST28 and its PFGE pattern was distinct from those of the others.

  2. Impact of Sub-Inhibitory Concentrations of Amoxicillin on Streptococcus suis Capsule Gene Expression and Inflammatory Potential

    PubMed Central

    Haas, Bruno; Grenier, Daniel

    2016-01-01

    Streptococcus suis is an important swine pathogen and emerging zoonotic agent worldwide causing meningitis, endocarditis, arthritis and septicemia. Among the 29 serotypes identified to date, serotype 2 is mostly isolated from diseased pigs. Although several virulence mechanisms have been characterized in S. suis, the pathogenesis of S. suis infections remains only partially understood. This study focuses on the response of S. suis P1/7 to sub-inhibitory concentrations of amoxicillin. First, capsule expression was monitored by qRT-PCR when S. suis was cultivated in the presence of amoxicillin. Then, the pro-inflammatory potential of S. suis P1/7 culture supernatants or whole cells conditioned with amoxicillin was evaluated by monitoring the activation of the NF-κB pathway in monocytes and quantifying pro-inflammatory cytokines secreted by macrophages. It was found that amoxicillin decreased capsule expression in S. suis. Moreover, conditioning the bacterium with sub-inhibitory concentrations of amoxicillin caused an increased activation of the NF-κB pathway in monocytes following exposure to bacterial culture supernatants and to a lesser extent to whole bacterial cells. This was associated with an increased secretion of pro-inflammatory cytokines (CXCL8, IL-6, IL-1β) by macrophages. This study identified a new mechanism by which S. suis may increase its inflammatory potential in the presence of sub-inhibitory concentrations of amoxicillin, a cell wall-active antibiotic, thus challenging its use for preventive treatments or as growth factor. PMID:27104570

  3. Characterization of DNase activity and gene in Streptococcus suis and evidence for a role as virulence factor

    PubMed Central

    2014-01-01

    Background The Gram-positive bacterium Streptococcus suis serotype 2 is an important swine pathogen and emerging zoonotic agent. Multilocus sequence typing allowed dividing S. suis serotype 2 into sequence types (STs). The three major STs of S. suis serotype 2 from North America are 1 (most virulent), 25 (intermediate virulence) and 28 (less virulent). Although the presence of DNase activity in S. suis has been previously reported, little data is available. The aim of this study was to investigate DNase activity in S. suis according to STs, to characterize the activity and gene, and to provide evidence for a potential role in virulence. Results We showed that ST1 and ST28 strains exhibited DNase activity that was absent in ST25 strains. The lack of activity in ST25 isolates was associated with a 14-bp deletion resulting in a shifted reading frame and a premature stop codon. The DNase of S. suis P1/7 (ST1) was cell-associated and active on linear DNA. A DNase-deficient mutant of S. suis P1/7 was found to be less virulent in an amoeba model. Stimulation of macrophages with the DNase mutant showed a decreased secretion of pro-inflammatory cytokines and matrix metalloproteinase-9 compared to the parental strain. Conclusions This study further expands our knowledge of S. suis DNase and its potential role in virulence. PMID:24996230

  4. Impact of Sub-Inhibitory Concentrations of Amoxicillin on Streptococcus suis Capsule Gene Expression and Inflammatory Potential.

    PubMed

    Haas, Bruno; Grenier, Daniel

    2016-04-19

    Streptococcus suis is an important swine pathogen and emerging zoonotic agent worldwide causing meningitis, endocarditis, arthritis and septicemia. Among the 29 serotypes identified to date, serotype 2 is mostly isolated from diseased pigs. Although several virulence mechanisms have been characterized in S. suis, the pathogenesis of S. suis infections remains only partially understood. This study focuses on the response of S. suis P1/7 to sub-inhibitory concentrations of amoxicillin. First, capsule expression was monitored by qRT-PCR when S. suis was cultivated in the presence of amoxicillin. Then, the pro-inflammatory potential of S. suis P1/7 culture supernatants or whole cells conditioned with amoxicillin was evaluated by monitoring the activation of the NF-κB pathway in monocytes and quantifying pro-inflammatory cytokines secreted by macrophages. It was found that amoxicillin decreased capsule expression in S. suis. Moreover, conditioning the bacterium with sub-inhibitory concentrations of amoxicillin caused an increased activation of the NF-κB pathway in monocytes following exposure to bacterial culture supernatants and to a lesser extent to whole bacterial cells. This was associated with an increased secretion of pro-inflammatory cytokines (CXCL8, IL-6, IL-1β) by macrophages. This study identified a new mechanism by which S. suis may increase its inflammatory potential in the presence of sub-inhibitory concentrations of amoxicillin, a cell wall-active antibiotic, thus challenging its use for preventive treatments or as growth factor.

  5. Survival of Streptococcus suis, Streptococcus dysgalactiae and Trueperella pyogenes in dry-cured Iberian pork shoulders and loins.

    PubMed

    Cardoso-Toset, F; Luque, I; Morales-Partera, A; Galán-Relaño, A; Barrero-Domínguez, B; Hernández, M; Gómez-Laguna, J

    2017-02-01

    Dry-cured hams, shoulders and loins of Iberian pigs are highly appreciated in national and international markets. Salting, additive addition and dehydration are the main strategies to produce these ready-to-eat products. Although the dry curing process is known to reduce the load of well-known food borne pathogens, studies evaluating the viability of other microorganisms in contaminated pork have not been performed. In this work, the efficacy of the dry curing process to eliminate three swine pathogens associated with pork carcass condemnation, Streptococcus suis, Streptococcus dysgalactiae and Trueperella pyogenes, was evaluated. Results of this study highlight that the dry curing process is a suitable method to obtain safe ready-to-eat products free of these microorganisms. Although salting of dry-cured shoulders had a moderate bactericidal effect, results of this study suggest that drying and ripening were the most important stages to obtain dry-cured products free of these microorganisms.

  6. Epidemiological relationship of human and swine Streptococcus suis isolates.

    PubMed

    Tarradas, C; Luque, I; de Andrés, D; Abdel-Aziz Shahein, Y E; Pons, P; González, F; Borge, C; Perea, A

    2001-06-01

    Two cases of meningitis due to Streptococcus suis in humans are reported here. A butcher and an abattoir worker were referred to a health centre in Castellón (Spain) with fever and symptoms of meningitis. After adequate treatment, a slight hipoacusia persisted as sequelae in both cases. Colonies of S. suis group R, serotype 2 and phenotype MRP+EF+ were isolated from cerebroespinal fluid. Epidemiological studies showed that both workers had in common the handling of pork meat of slaughtered healthy pigs from three closed farms. A study of the tonsils from apparently healthy, slaughtered pigs was carried out. A total of 234 tonsillar samples were obtained and 81 strains of S. suis were isolated from them. Serotype 2 appeared to be the most frequent (50.6%), and the analysis for phenotype showed a high percentage of tonsillar strains with the phenotype MRP+EF+ (35.9%). The humans and 28 tonsillar swine strains showed a similar profile (S. suis group R, serotype 2 and phenotype MRP+EF+). A total of 26 of the swine isolates were analysed by ribotyping using EcoRI. The human strains showed the same six-band hybridization pattern that shared five bands with the pattern most frequently shown by most of the tonsillar N. suis group R, serotype 2 and phenotype MRP+EF+ strains, differing only in the lightest, faintest band which was slightly less anodical in human (> or = 1.8 kb) than in swine (approximately 1.8 kb). From these results, both groups of strains, humans and porcine, showed differences; how can these differences in the pattern of ribotyping be explained if they should have the same origin? Is it possible that they have undergone an adaptation to the new host or perhaps the modification is due to other unknown causes? Further studies in this area are required in order to answer these questions.

  7. Acute meningitis of piglets and mice caused by co-infected with Streptococcus suis and Aerococcus viridans.

    PubMed

    Pan, Zihao; Ma, Ye; Ma, Jiale; Dong, Wenyang; Yao, Huochun

    2016-11-02

    The two opportunistic pathogens, Streptococcus suis (S. suis) and Aerococcus. viridans (A. viridans) were isolated from the brains of piglets suffered bacterial meningitis in a farm of China. The murine model has been established to evaluate the pathogenicity and symbiotic relationship of S. suis and A. viridans simultaneously infection. Our results demonstrated the ability of new serotype S. suis to cause the classical bacterial meningitis and death were greatly enhanced during co-infection with A. viridans in mice at a proportion. We also examined the distribution and titer of bacteria coinfection in organs, the titer of S. suis appeared a significant trend for an increase in the lung meanwhile the concentration titer of A. viridans maintain a low level. This is the first reported the A. viridans and S. suis coinfection cause the bacterial meningitis outbroke in the piglets and mice. Moreover, further investigation of the pathogenesis of A. viridans and S. suis is urgently needed in swine industry.

  8. The type II histidine triad protein HtpsC is a novel adhesion with the involvement of Streptococcus suis virulence

    PubMed Central

    Li, Min; Shao, Zhu-Qing; Guo, Yuqing; Wang, Ling; Hou, Tianqing; Hu, Dan; Zheng, Feng; Tang, Jiaqi; Wang, Changjun; Feng, Youjun; Gao, Jimin; Pan, Xiuzhen

    2015-01-01

    Streptococcal histidine triad proteins HTPs are widely distributed within the Streptococcus genus. Based on the phylogenetic relationship and domain composition, HTPs are classified into type I and type II subfamilies. Previous studies revealed that several pathogenic streptococci contain more than one htp gene. We found that the highly virulent strain of Streptococcus suis 2 (S. suis 2), 05ZYH33 encodes 3 HTPs, designated HtpsA (previously described as HtpS), HtpsB, and HtpsC. Among them, HtpsC is the only member that contains leucine-rich repeat (LRR) domains at the C-terminal. In this study, we demonstrated that the recombinant HtpsC could bind to 2 different components of human ECM complex laminin and fibronectin in vitro, suggesting that it is a novel adhesin of S. suis 2. Having constructed an htpsC mutant, we evaluated its role in the pathogenesis of the highly virulent S. suis 2 strain 05ZYH33. Our data showed that inactivation of htpsC significantly affected adherence of S. suis 2 to Hep-2 cells and shortened the survival of the bacteria in whole blood. Furthermore, deletion of htpsC significantly attenuated the virulence of S. suis 2 in mice. These results demonstrated that htpsC was involved in the pathogenesis of the highly virulent S. suis 2 strain 05ZYH33. In line with the observation, immunization with HtpsC significantly prolonged mice's survival after S. suis 05ZYH33 challenge, indicating its potential use in the vaccine development against S. suis. PMID:26151575

  9. Changes in abundance of Lactobacillus spp. and Streptococcus suis in the stomach, jejunum and ileum of piglets after weaning.

    PubMed

    Su, Yong; Yao, Wen; Perez-Gutierrez, Odette N; Smidt, Hauke; Zhu, Wei-Yun

    2008-12-01

    This present study investigated the changes in bacterial community composition, with an emphasis on Lactobacillus spp. and Streptococcus suis populations as potentially beneficial and harmful groups, in the stomach, jejunum and ileum of piglets after weaning (21 days postpartum) by 16S rRNA gene-based methods. Denaturing gradient gel electrophoresis analysis showed that, after weaning, predominant bands related to Lactobacillus spp. disappeared and were replaced by potential pathogenic species, such as Peptostreptococcus anaerobius, Moraxella cuniculi, S. suis and Porphyromonas catoniae. Real-time PCR revealed that the abundances of lactobacilli and Lactobacillus sobrius as a proportion of total bacterial abundance were significantly lower in the stomach, jejunum and ileum of weaned piglets than in 21-day-old piglets. A specific and sensitive real-time PCR assay was developed for quantification of the important pathogen S. suis within gastrointestinal microbiota. The assay showed that S. suis predominated in the stomach samples of weaned piglets with population levels up to 10(7) copies g(-1) digesta, while it was not detected in the stomach before weaning. Streptococcus suis was not dominant in the jejunum and ileum digesta before weaning, but became dominant after weaning, with population levels up to 10(7) copies g(-1) digesta. The results demonstrated for the first time the postweaning dominance of the potentially harmful S. suis in piglet intestine. The results also suggest that the defensive barrier of the stomach can be impaired as S. suis became dominant while the proportion of Lactobacillus populations decreased after weaning, which may further result in an increase of S. suis abundance in the intestine.

  10. Detection and molecular typing of Streptococcus suis in tonsils from live pigs in France

    PubMed Central

    Marois, Corinne; Le Devendec, Laëtitia; Gottschalk, Marcelo; Kobisch, Marylène

    2007-01-01

    Streptococcus suis is an important pathogen of swine, causing meningitis, arthritis, polyserositis, septicemia, and sudden death in weaning piglets as well as fattening pigs. Recently, 3 molecular tests have been developed in our laboratory: a multiplex polymerase chain reaction (m-PCR) assay for the detection of S. suis species and serotypes 2 and 1/2, and 2 molecular typing methods, pulsed-field gel electrophoresis and an approach based on PCR amplification of a fragment of rRNA genes, including a part of the 16S and 23S genes and the 16S–23S rDNA intergenic spacer region (ISR), followed by restriction fragment length polymorphism (RFLP) analysis (ISR-RFLP). In the present study, we used these tests to analyze tonsil samples from clinically healthy pigs and to identify individual isolates of S. suis during epidemiologic investigations of 8 related herds with a history of septicemia caused by S. suis serotype 2. Capsular typing showed that 58% of the strains were nontypable. Of the 17 serotypes present, serotype 22 was the most prevalent. In the 7 farms without clinical signs on the day of sampling, we detected S. suis serotype 2 or 1/2, or both, in less than 5% of the pigs by m-PCR or by bacteriologic culture. In the 8th farm, on which 2 pigs had clinical signs of septicemia on the day of sampling, we detected S. suis serotype 2 or 1/2, or both, by m-PCR in the tonsils of 40% of fattening pigs (21 wk old) that lacked symptoms. Molecular typing of the serotype 2 strains showed a common origin of contamination in these herds, given that 1 pattern (C1) was detected in the isolates from 6 of the 8 herds. However, up to 4 patterns were associated with septicemia and sudden death. Several patterns of S. suis serotype 2 can be responsible for disease in the same herd. These molecular tools may be useful for confident studies of the transmission of S. suis, thereby contributing to the control of S. suis infection. PMID:17193877

  11. Contribution of NADH oxidase to oxidative stress tolerance and virulence of Streptococcus suis serotype 2.

    PubMed

    Zheng, Chengkun; Ren, Sujing; Xu, Jiali; Zhao, Xigong; Shi, Guolin; Wu, Jianping; Li, Jinquan; Chen, Huanchun; Bei, Weicheng

    2017-01-02

    Streptococcus suis is a major swine and zoonotic pathogen that causes severe infections. Previously, we identified 2 Spx regulators in S. suis, and demonstrated that SpxA1 affects oxidative stress tolerance and virulence. However, the mechanism behind SpxA1 function remains unclear. In this study, we targeted 4 genes that were expressed at significantly reduced levels in the spxA1 mutant, to determine their specific roles in adaptation to oxidative stress and virulence potential. The Δnox strain exhibited impaired growth under oxidative stress conditions, suggesting that NADH oxidase is involved in oxidative stress tolerance. Using murine and pig infection models, we demonstrate for the first time that NADH oxidase is required for virulence in S. suis 2. Furthermore, the enzymatic activity of NADH oxidase has a key role in oxidative stress tolerance and a secondary role in virulence. Collectively, our findings reveal that NADH oxidase plays an important part in SpxA1 function and provide a new insight into the pathogenesis of S. suis 2.

  12. Streptococcus suis sorption on agricultural soils: role of soil physico-chemical properties.

    PubMed

    Zhao, Wenqiang; Liu, Xing; Huang, Qiaoyun; Cai, Peng

    2015-01-01

    Understanding pathogen sorption on natural soil particles is crucial to protect public health from soilborne and waterborne diseases. Sorption of pathogen Streptococcus suis on 10 agricultural soils was examined, and its correlations with soil physico-chemical properties were also elucidated. S. suis sorption isotherms conformed to the linear equation, with partition coefficients (Ks) ranging from 12.7 mL g(-1) to 100.1 mL g(-1). Bacteria were observed to sorb on the external surfaces of soil aggregates by scanning electron microscopy. Using Pearson correlation and linear regression analysis, solution pH was found to have significant negative correlations with Ks. Stepwise multiple regression and path analysis revealed that pH and cation exchange capacity (CEC) were the main factors influencing sorption behaviors. The obtained overall model (Ks=389.6-45.9×pH-1.3×CEC, R(2)=0.943, P<0.001) can accurately predict Ks values. However, the variability in Ks was less dependent on soil organic matter, specific surface area, soil texture and zeta potential, probably due to the internal-surface shielding phenomenon of soil aggregates. Additionally, the sorption trends cannot be interpreted by interaction energy barriers calculated using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, suggesting the limits of DLVO theory in describing pathogen sorption on natural soils. Our results also indicated soil pH and CEC should be preferentially considered when modeling S. suis sorption process.

  13. Streptococcal Adhesin P (SadP) contributes to Streptococcus suis adhesion to the human intestinal epithelium

    PubMed Central

    Ferrando, Maria Laura; Willemse, Niels; Zaccaria, Edoardo; Pannekoek, Yvonne; van der Ende, Arie; Schultsz, Constance

    2017-01-01

    Background Streptococcus suis is a zoonotic pathogen, causing meningitis and septicemia. We previously demonstrated that the gastrointestinal tract (GIT) is an entry site for zoonotic S. suis infection. Here we studied the contribution of Streptococcal adhesin Protein (SadP) to host-pathogen interaction at GIT level. Methods SadP expression in presence of Intestinal Epithelial Cells (IEC) was compared with expression of other virulence factors by measuring transcript levels using quantitative Real Time PCR (qRT-PCR). SadP variants were identified by phylogenetic analysis of complete DNA sequences. The interaction of SadP knockout and complementation mutants with IEC was tested in vitro. Results Expression of sadP was significantly increased in presence of IEC. Sequence analysis of 116 invasive strains revealed five SadP sequence variants, correlating with genotype. SadP1, present in zoonotic isolates of clonal complex 1, contributed to binding to both human and porcine IEC and translocation across human IEC. Antibodies against the globotriaosylceramide Gb3/CD77 receptor significantly inhibited adhesion to human IEC. Conclusion SadP is involved in the host-pathogen interaction in the GIT. Differences between SadP variants may determine different affinities to the Gb3/CD77 host-receptor, contributing to variation in adhesion capacity to host IEC and thus to S. suis zoonotic potential. PMID:28407026

  14. Streptococcus suis Capsular Polysaccharide Inhibits Phagocytosis through Destabilization of Lipid Microdomains and Prevents Lactosylceramide-Dependent Recognition

    PubMed Central

    Houde, Mathieu; Gottschalk, Marcelo; Gagnon, Fleur; Van Calsteren, Marie-Rose

    2012-01-01

    Streptococcus suis type 2 is a major swine pathogen and a zoonotic agent, causing meningitis in both 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 fact, nonencapsulated mutants are easily internalized and killed by macrophages and dendritic cells. The objective of this work was to study the molecular mechanisms by which the CPS of S. suis prevents phagocytosis. By using latex beads covalently linked with purified CPS, it was shown that CPS itself was sufficient to inhibit entry of both latex beads and bystander fluorescent beads into macrophages. Upon contact with macrophages, encapsulated S. suis was shown to destabilize lipid microdomains at the cell surface, to block nitric oxide (NO) production during infection, and to prevent lactosylceramide accumulation at the phagocytic cup during infection. In contrast, the nonencapsulated mutant was easily internalized via lipid rafts, in a filipin-sensitive manner, leading to lactosylceramide recruitment and strong NO production. This is the first report to identify a role for CPS in lipid microdomain stability and to recognize an interaction between S. suis and lactosylceramide in phagocytes. PMID:22124659

  15. The 1910HK/RR two-component system is essential for the virulence of Streptococcus suis serotype 2.

    PubMed

    Yuan, Fangyan; Tan, Chen; Liu, Zewen; Yang, Keli; Zhou, Danna; Liu, Wei; Duan, Zhengying; Guo, Rui; Chen, Huanchun; Tian, Yongxiang; Bei, Weicheng

    2017-03-01

    Streptococcus suis serotype 2 is a major zoonotic pathogen, and the two-component system plays an important role in bacterial pathogenesis. The present study targeted the 1910HK/RR two-component system of S. suis 2. A 1910HK/RR deletion mutant (Δ1910HK/RR) and the corresponding complementation strain (CΔ1910HK/RR) were constructed in S. suis 2 strain 05ZYH33. 1910HK/RR deletion had no effect on S. suis 2 growth, but significantly inhibited the adherence and invasion of S. suis 2 to HEp-2 cells. Analysis of the role of 1910HK/RR in murine and pig infection models demonstrated that 1910HK/RR played a distinct role in the virulence of S. suis 2. In addition, deletion of 1910HK/RR significantly impaired the survival of 05ZYH33 in human blood. These data provided important insights into the pathogenesis of S. suis 2.

  16. Astrocytes Enhance Streptococcus suis-Glial Cell Interaction in Primary Astrocyte-Microglial Cell Co-Cultures.

    PubMed

    Seele, Jana; Nau, Roland; Prajeeth, Chittappen K; Stangel, Martin; Valentin-Weigand, Peter; Seitz, Maren

    2016-06-13

    Streptococcus (S.) suis infections are the most common cause of meningitis in pigs. Moreover, S. suis is a zoonotic pathogen, which can lead to meningitis in humans, mainly in adults. We assume that glial cells may play a crucial role in host-pathogen interactions during S. suis infection of the central nervous system. Glial cells are considered to possess important functions during inflammation and injury of the brain in bacterial meningitis. In the present study, we established primary astrocyte-microglial cell co-cultures to investigate interactions of S. suis with glial cells. For this purpose, microglial cells and astrocytes were isolated from new-born mouse brains and characterized by flow cytometry, followed by the establishment of astrocyte and microglial cell mono-cultures as well as astrocyte-microglial cell co-cultures. In addition, we prepared microglial cell mono-cultures co-incubated with uninfected astrocyte mono-culture supernatants and astrocyte mono-cultures co-incubated with uninfected microglial cell mono-culture supernatants. After infection of the different cell cultures with S. suis, bacteria-cell association was mainly observed with microglial cells and most prominently with a non-encapsulated mutant of S. suis. A time-dependent induction of NO release was found only in the co-cultures and after co-incubation of microglial cells with uninfected supernatants of astrocyte mono-cultures mainly after infection with the capsular mutant. Only moderate cytotoxic effects were found in co-cultured glial cells after infection with S. suis. Taken together, astrocytes and astrocyte supernatants increased interaction of microglial cells with S. suis. Astrocyte-microglial cell co-cultures are suitable to study S. suis infections and bacteria-cell association as well as NO release by microglial cells was enhanced in the presence of astrocytes.

  17. Neutrophil extracellular Taps play an important role in clearance of Streptococcus suis in vivo.

    PubMed

    Zhao, Jianqing; Lin, Lan; Fu, Lei; Han, Li; Zhang, Anding

    2016-04-01

    Streptococcus suis infection induces formation of neutrophil extracellular traps (NETs) in vitro; however, the contribution of NETs-mediated killing to the pathogenesis of S. suis in vivo is yet to be elicited. The findings of the present study indicated that extracellular DNA fiber can be induced in a murine model in response to S. suis infection. A nuclease that destroys their structure was used to evaluate the role of NETs on S. suis infection. Treatment with nuclease resulted in a greater bacteria load and higher serum TNF-α concentrations in response to S. suis infection, indicating that NETs structure played an essential role in S. suis clearance and inflammation. Furthermore, nuclease treatment resulted in more severe clinical signs during and higher mortality from S. suis infection. These findings indicated that NETs structure contributes to protection against S. suis infection.

  18. A locus encoding variable defence systems against invading DNA identified in Streptococcus suis.

    PubMed

    Okura, Masatoshi; Nozawa, Takashi; Watanabe, Takayasu; Murase, Kazunori; Nakagawa, Ichiro; Takamatsu, Daisuke; Osaki, Makoto; Sekizaki, Tsutomu; Gottschalk, Marcelo; Hamada, Shigeyuki; Maruyama, Fumito

    2017-04-04

    Streptococcus suis, an important zoonotic pathogen, is known to have an open pan-genome and to develop a competent state. In S. suis, limited genetic lineages are suggested to be associated with zoonosis. However, little is known about the evolution of diversified lineages and their respective phenotypic or ecological characteristics. In this study, we performed comparative genome analyses of S. suis, with a focus on the competence genes, mobile genetic elements (MGEs), and genetic elements related to various defence systems against exogenous DNAs (defence elements) that are associated with gene gain/loss/exchange mediated by horizontal DNA movements and their restrictions. Our genome analyses revealed a conserved competence-inducing peptide type (pherotype) of the competence system and large-scale genome rearrangements in certain clusters based on the genome phylogeny of 58 S. suis strains. Moreover, the profiles of the defence elements were similar or identical to each other among the strains belonging to the same genomic clusters. Our findings suggest that these genetic characteristics of each cluster might exert specific effects on the phenotypic or ecological differences between the clusters. We also found certain loci that shift several types of defence elements in S. suis. Of note, one of these loci is a previously unrecognised variable region in bacteria, at which strains of distinct clusters code for different and various defence elements. This locus might represent a novel defence mechanism that has evolved via an arms race between bacteria and invading DNAs, mediated by MGEs and genetic competence. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. [Streptococcus pyogenes pathogenic factors].

    PubMed

    Bidet, Ph; Bonacorsi, S

    2014-11-01

    The pathogenicity of ß-hemolytic group A streptococcus (GAS) is particularly diverse, ranging from mild infections, such as pharyngitis or impetigo, to potentially debilitating poststreptococcal diseases, and up to severe invasive infections such as necrotizing fasciitis or the dreaded streptococcal toxic shock syndrome. This variety of clinical expressions, often radically different in individuals infected with the same strain, results from a complex interaction between the bacterial virulence factors, the mode of infection and the immune system of the host. Advances in comparative genomics have led to a better understanding of how, following this confrontation, GAS adapts to the immune system's pressure, either peacefully by reducing the expression of certain virulence factors to achieve an asymptomatic carriage, or on the contrary, by overexpressing them disproportionately, resulting in the most severe forms of invasive infection.

  20. Purification and characterization of the subtilisin-like protease of Streptococcus suis that contributes to its virulence.

    PubMed

    Bonifait, Laetitia; Vaillancourt, Katy; Gottschalk, Marcelo; Frenette, Michel; Grenier, Daniel

    2011-03-24

    Streptococcus suis is a major swine pathogen that is responsible for severe infections such as meningitis, endocarditis, and septicemia. S. suis is also recognized as a zoonotic agent and expresses several virulence factors. The recently identified subtilisin-like protease (SspA) of S. suis plays an important role in the pathogenicity of this bacterium in animal models. The objective of the present study was to clone, purify, and characterize the SspA of serotype 2 S. suis P1/7. The SSU0757 gene encoding SspA was amplified and a 4798-bp DNA fragment was obtained. It was cloned into the expression plasmid pBAD/HisB and then inserted into Escherichia coli to overproduce the protein. The recombinant protease was purified by chromatography procedures and showed a molecular weight of 170 kDa by SDS-PAGE. Its activity was optimal at pH 7 and at temperatures ranging from 25°C to 37°C. It had a high specificity for the chromogenic substrate succinyl-Ala-Ala-Pro-Phe-pNa while specific inhibitors of serine proteases inhibited its activity. In addition to degrading gelatin, the protease hydrolyzed the Aα chain of fibrinogen, which prevented fibrin formation by thrombin. The recombinant subtilisin-like protease also showed toxicity towards brain microvascular endothelial cells. Lastly, sera from pigs infected with S. suis reacted with the recombinant SspA, indicating that it is produced during infections. In conclusion, the SspA of S. suis shared similarities with subtilisin-like proteases produced by other pathogenic streptococci and may contribute to the pathogenic process of S. suis infections.

  1. Insight into the Interaction of Metal Ions with TroA from Streptococcus suis

    PubMed Central

    Zheng, Beiwen; Zhang, Qiangmin; Gao, Jia; Han, Huiming; Li, Ming; Zhang, Jingren; Qi, Jianxun; Yan, Jinghua; Gao, George F.

    2011-01-01

    Background 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. Methodology/Principal Findings Here we determined the crystal structure of SsTroA from a highly pathogenic streptococcal toxic shock syndrome (STSS)-causing Streptococcus suis in complex with zinc. Inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that apo-SsTroA binds Zn2+ and Mn2+. Both metals bind to SsTroA with nanomolar affinity and stabilize the protein against thermal unfolding. Zn2+ and Mn2+ induce distinct conformational changes in SsTroA compared with the apo form as confirmed by both circular dichroism (CD) and nuclear magnetic resonance (NMR) spectra. NMR data also revealed that Zn2+/Mn2+ bind to SsTroA in either the same site or an adjacent region. Finally, we found that the folding of the metal-bound protein is more compact than the corresponding apoprotein. Conclusions/Significance Our findings reveal a mechanism for uptake of metal ions in S. suis and this mechanism provides a reasonable explanation as to how SsTroA operates in metal transport. PMID:21611125

  2. Streptococcus suis in invasive human infections in Poland: clonality and determinants of virulence and antimicrobial resistance.

    PubMed

    Bojarska, A; Molska, E; Janas, K; Skoczyńska, A; Stefaniuk, E; Hryniewicz, W; Sadowy, E

    2016-06-01

    The purpose of this study was to perform an analysis of Streptococcus suis human invasive isolates, collected in Poland by the National Reference Centre for Bacterial Meningitis. Isolates obtained from 21 patients during 2000-2013 were investigated by phenotypic tests, multilocus sequence typing (MLST), analysis of the TR9 locus from the multilocus variable number tandem repeat (VNTR) analysis (MLVA) scheme and pulsed-field gel electrophoresis (PFGE) of SmaI-digested DNA. Determinants of virulence and antimicrobial resistance were detected by polymerase chain reaction (PCR) and analysed by sequencing. All isolates represented sequence type 1 (ST1) and were suggested to be serotype 2. PFGE and analysis of the TR9 locus allowed the discrimination of four and 17 types, respectively. Most of the isolates were haemolysis- and DNase-positive, and around half of them formed biofilm. Genes encoding suilysin, extracellular protein factor, fibronectin-binding protein, muramidase-released protein, surface antigen one, enolase, serum opacity factor and pili were ubiquitous in the studied group, while none of the isolates carried sequences characteristic for the 89K pathogenicity island. All isolates were susceptible to penicillin, cefotaxime, imipenem, moxifloxacin, chloramphenicol, rifampicin, gentamicin, linezolid, vancomycin and daptomycin. Five isolates (24 %) were concomitantly non-susceptible to erythromycin, clindamycin and tetracycline, and harboured the tet(O) and erm(B) genes; for one isolate, lsa(E) and lnu(B) were additionally detected. Streptococcus suis isolated in Poland from human invasive infections belongs to a globally distributed clonal complex of this pathogen, enriched in virulence markers. This is the first report of the lsa(E) and lnu(B) resistance genes in S. suis.

  3. [Isolation and identification of Streptococcus suis serotype 2 from sick-pig samples of Sichuan province].

    PubMed

    Zhu, Hong; He, Jun; Jing, Hong-bo; Wang, Zheng-qiang; Duan, Qing

    2006-08-01

    Streptococcus suis serotype 2 (SS2) is a major pathogen frequently associated with infections in pigs. There are presently 35 serotypes of S.suis (serotype 1 to 34 and serotype 1/2) recognized on the basis of capsular antigens. Few people were reported to infect with SS2 in the past years. However, an accidental case happened in Sichuan province of China in 2005. Some people got ill and died, and all of them were closely contacted with sick pigs. Based on clinical features and epidemiologic data, this case could be caused by SS2 infection. Liver, spleen, kidney, lung and serum samples were collected and used for pathogen isolation and identification in laboratory, three strain bacteria were isolated. The three strains of SS2 showed typical morphology of SS2 on blood agar and under microscope with Gram stain. They were also agglutinated with standard serum of SS2. Biochemical characteristics of the three bacteria were tested using API 20 strep and analyzed by API software (version 3.3), results showed they were SS2. Four pairs of primer were designed, which were exactly matched the extracellular factor gene, muraminidase released protein gene, capsular polysaccharides gene and 16S rRNA gene respectively. These primers were used on polymerase chain reaction (PCR), and the PCR products were 626bp, 885bp, 487bp and 297bp on agarose gel, respectively. Drug sensitivity test were also done and results showed that they were sensitive to cefazolin, clindamycin, erythromycin, levofloxacin, nitrofurantoin, penicillin-G, and vancomycin and resistive to tetracycline. Balb/c mice infected with the isolated SS2 strain showed swelling in stomach and intestine, cyanochroia at mouth and suggillation under skin, which were similar to the clinical features of patients. Streptococcus suis serotype 2 were also found on lung sheeting sample under microscope with Gram stain. Rabbits infected with the isolated SS2 showed the similar clinical features with mice.

  4. Mac Protein is not an Essential Virulence Factor for the Virulent Reference Strain Streptococcus suis P1/7.

    PubMed

    Xiao, Genhui; Wu, Zongfu; Zhang, Shouming; Tang, Huanyu; Wang, Fengqiu; Lu, Chengping

    2017-01-01

    Streptococcus suis is a major pathogen of pigs and also an important zoonotic agent for humans. A S. suis protein containing Mac-1 domain (designated Mac) is a protective antigen, exclusively cleaves porcine IgM, and contributes to complement evasion with the presence of high titers of specific porcine anti-S. suis IgM, but its role in S. suis virulence has not been investigated in natural healthy host without specific IgM. In this study, a mac deletion mutant was constructed by homologous recombination in S. suis serotype 2 virulent reference strain P1/7. Deletion of mac did not significantly influence phagocytosis or intracellular survival within murine macrophages RAW264.7, or the oxidative-burst induction of RAW264.7 and murine neutrophils. Furthermore, the mutant is as virulent as the wild-type strain in pig, mouse, and zebrafish infection models. Our data suggest that Mac is not essential for S. suis virulence in strain P1/7 in natural healthy host without specific IgM, and the immunogenicity of Mac does not appear to correlate with its significance for virulence.

  5. Comparative Genomics Study of Multi-Drug-Resistance Mechanisms in the Antibiotic-Resistant Streptococcus suis R61 Strain

    PubMed Central

    Zhang, Anding; Wu, Jiayan; Chen, Bo; Hua, Yafeng; Yu, Jun; Chen, Huanchun; Xiao, Jingfa; Jin, Meilin

    2011-01-01

    Background 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. Results In our study, we sequenced one multi-drug-resistant S. suis strain, R61, and one S. suis strain, A7, which is fully sensitive to all tested antibiotics. Comparative genomic analysis revealed that the R61 strain is phylogenetically distinct from other S. suis strains, and the genome of R61 exhibits extreme levels of evolutionary plasticity with high levels of gene gain and loss. Our results indicate that the multi-drug-resistant strain R61 has evolved three main categories of resistance. Conclusions Comparative genomic analysis of S. suis strains with diverse drug-resistant phenotypes provided evidence that horizontal gene transfer is an important evolutionary force in shaping the genome of multi-drug-resistant strain R61. In this study, we discovered novel and previously unexamined mutations that are strong candidates for conferring drug resistance. We believe that these mutations will provide crucial clues for designing new drugs against this pathogen. In addition, our work provides a clear demonstration that the use of drugs has driven the emergence of the multi-drug-resistant strain R61. PMID:21966396

  6. The arginine-ornithine antiporter ArcD contributes to biological fitness of Streptococcus suis.

    PubMed

    Fulde, Marcus; Willenborg, Joerg; Huber, Claudia; Hitzmann, Angela; Willms, Daniela; Seitz, Maren; Eisenreich, Wolfgang; Valentin-Weigand, Peter; Goethe, Ralph

    2014-01-01

    The arginine-ornithine antiporter (ArcD) is part of the Arginine Deiminase System (ADS), a catabolic, energy-providing pathway found in a variety of different bacterial species, including the porcine zoonotic pathogen Streptococcus suis. The ADS has recently been shown to play a role in the pathogenicity of S. suis, in particular in its survival in host cells. The contribution of arginine and arginine transport mediated by ArcD, however, has yet to be clarified. In the present study, we showed by experiments using [U-(13)C6]arginine as a tracer molecule that S. suis is auxotrophic for arginine and that bacterial growth depends on the uptake of extracellular arginine. To further study the role of ArcD in arginine metabolism, we generated an arcD-specific mutant strain and characterized its growth compared to the wild-type (WT) strain, a virulent serotype 2 strain. The mutant strain showed a markedly reduced growth in chemically defined media supplemented with arginine when compared to the WT strain, suggesting that ArcD promotes arginine uptake. To further evaluate the in vivo relevance of ArcD, we studied the intracellular bacterial survival of the arcD mutant strain in an epithelial cell culture infection model. The mutant strain was substantially attenuated, and its reduced intracellular survival rate correlated with a lower ability to neutralize the acidified environment. Based on these results, we propose that ArcD, by its function as an arginine-ornithine antiporter, is important for supplying arginine as substrate of the ADS and, thereby, contributes to biological fitness and virulence of S. suis in the host.

  7. The arginine-ornithine antiporter ArcD contributes to biological fitness of Streptococcus suis

    PubMed Central

    Fulde, Marcus; Willenborg, Joerg; Huber, Claudia; Hitzmann, Angela; Willms, Daniela; Seitz, Maren; Eisenreich, Wolfgang; Valentin-Weigand, Peter; Goethe, Ralph

    2014-01-01

    The arginine-ornithine antiporter (ArcD) is part of the Arginine Deiminase System (ADS), a catabolic, energy-providing pathway found in a variety of different bacterial species, including the porcine zoonotic pathogen Streptococcus suis. The ADS has recently been shown to play a role in the pathogenicity of S. suis, in particular in its survival in host cells. The contribution of arginine and arginine transport mediated by ArcD, however, has yet to be clarified. In the present study, we showed by experiments using [U-13C6]arginine as a tracer molecule that S. suis is auxotrophic for arginine and that bacterial growth depends on the uptake of extracellular arginine. To further study the role of ArcD in arginine metabolism, we generated an arcD-specific mutant strain and characterized its growth compared to the wild-type (WT) strain, a virulent serotype 2 strain. The mutant strain showed a markedly reduced growth in chemically defined media supplemented with arginine when compared to the WT strain, suggesting that ArcD promotes arginine uptake. To further evaluate the in vivo relevance of ArcD, we studied the intracellular bacterial survival of the arcD mutant strain in an epithelial cell culture infection model. The mutant strain was substantially attenuated, and its reduced intracellular survival rate correlated with a lower ability to neutralize the acidified environment. Based on these results, we propose that ArcD, by its function as an arginine-ornithine antiporter, is important for supplying arginine as substrate of the ADS and, thereby, contributes to biological fitness and virulence of S. suis in the host. PMID:25161959

  8. Genetic diversity of Streptococcus suis serotype 2 isolated from pigs in Brazil.

    PubMed

    Doto, Daniela Sabatini; Moreno, Luisa Zanolli; Calderaro, Franco Ferraro; Matajira, Carlos Emilio Cabrera; de Moura Gomes, Vasco Tulio; Ferreira, Thais Sebastiana Porfida; Mesquita, Renan Elias; Timenetsky, Jorge; Gottschalk, Marcelo; Moreno, Andrea Micke

    2016-04-01

    Streptococcus suis is an emerging zoonotic pathogen that causes septicemia, meningitis, arthritis, and pneumonia in swine and humans. The present study aimed to characterize the genetic diversity of S. suis serotype 2 isolated from pigs showing signs of illness in Brazil using pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and profiling of virulence-associated markers. A total of 110 isolates were studied, 62.7% of which were isolated from the central nervous system and 19.1% from the respiratory tract. Eight genotypes were obtained from the combination of virulence genes, with 43.6% and 5.5% frequencies for the mrp (+) /epf (+) /sly (+) and mrp (-) /epf (-) /sly (-) genotypes, respectively. The presence of isolates with epf gene variation with higher molecular weight also appears to be a characteristic of Brazilian S. suis serotype 2. The PFGE and SE-AFLP were able to type all isolates and, although they presented a slight tendency to cluster according to state and year of isolation, it was also evident the grouping of different herds in the same PFGE subtype and the existence of isolates originated from the same herd classified into distinct subtypes. No further correlation between the isolation sites and mrp/epf/sly genotypes was observed.

  9. Genetic diversity of Streptococcus suis serotype 2 isolated from pigs in Brazil

    PubMed Central

    Doto, Daniela Sabatini; Moreno, Luisa Zanolli; Calderaro, Franco Ferraro; Matajira, Carlos Emilio Cabrera; de Moura Gomes, Vasco Tulio; Ferreira, Thais Sebastiana Porfida; Mesquita, Renan Elias; Timenetsky, Jorge; Gottschalk, Marcelo; Moreno, Andrea Micke

    2016-01-01

    Streptococcus suis is an emerging zoonotic pathogen that causes septicemia, meningitis, arthritis, and pneumonia in swine and humans. The present study aimed to characterize the genetic diversity of S. suis serotype 2 isolated from pigs showing signs of illness in Brazil using pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and profiling of virulence-associated markers. A total of 110 isolates were studied, 62.7% of which were isolated from the central nervous system and 19.1% from the respiratory tract. Eight genotypes were obtained from the combination of virulence genes, with 43.6% and 5.5% frequencies for the mrp+/epf+/sly+ and mrp−/epf−/sly− genotypes, respectively. The presence of isolates with epf gene variation with higher molecular weight also appears to be a characteristic of Brazilian S. suis serotype 2. The PFGE and SE-AFLP were able to type all isolates and, although they presented a slight tendency to cluster according to state and year of isolation, it was also evident the grouping of different herds in the same PFGE subtype and the existence of isolates originated from the same herd classified into distinct subtypes. No further correlation between the isolation sites and mrp/epf/sly genotypes was observed. PMID:27127337

  10. Isolation and characterization of a native avirulent strain of Streptococcus suis serotype 2: a perspective for vaccine development

    PubMed Central

    Yao, Xinyue; Li, Ming; Wang, Jing; Wang, Changjun; Hu, Dan; Zheng, Feng; Pan, Xiuzhen; Tan, Yinling; Zhao, Yan; Hu, Liwen; Tang, Jiaqi; Hu, Fuquan

    2015-01-01

    Streptococcus suis, an emerging infectious pathogen, is the cause of two large-scale outbreaks of human streptococcal toxic shock syndrome in China, and has attracted much attention from the scientific community. The genetic basis of its pathogenesis remains enigmatic, and no effective prevention measures have been established. To better understand the virulence differentiation of S. suis and develop a promising vaccine, we isolated and sequenced a native avirulent S. suis strain (05HAS68). Animal experiments revealed that 05HAS68 is an avirulent strain and could protect piglets from the attack of virulent strains. Comparative genomics analyses demonstrated the genetic basis for the lack of virulence in 05HAS68, which is characterized by the absence of some important virulence-associated factors and the intact 89K pathogenicity island. Lack of virulence was also illustrated by reduced survival of 05HAS68 compared to a virulent strain in pig whole blood. Further investigations revealed a large-scale genomic rearrangement in 05HAS68, which was proposed to be mediated by transposase genes and/or prophages. This genomic rearrangement may have caused the genomic diversity of S. suis, and resulted in biological discrepancies between 05HAS68 and highly virulent S. suis strains. PMID:25891917

  11. Hyaluronate lyase activity of Streptococcus suis serotype 2 and modulatory effects of hyaluronic acid on the bacterium's virulence properties.

    PubMed

    Haas, Bruno; Vaillancourt, Katy; Bonifait, Laetitia; Gottschalk, Marcelo; Grenier, Daniel

    2015-11-26

    Streptococcus suis serotype 2 is a major swine pathogen and zoonotic agent worldwide causing mainly meningitis and septicemia. Hyaluronate lyases are enzymes that degrade hyaluronic acid, a major constituent of animal tissues, and have been reported as virulence factors in various bacterial species. Since the hyaluronate lyase of S. suis has been considered ambiguously as a virulence factor, we screened 50 isolates from the three major clonal complexes found in North America (sequence type [ST] 1, ST25, and ST28) known to differ in their degree of virulence in order to link the presence or absence of this activity with the degree of virulence. Moreover, the effect of exogenous hyaluronic acid on S. suis virulence factor gene expression and the pro-inflammatory response of brain macrovascular endothelial cells (BMEC) was also investigated. We found that all but one ST1 isolates (high virulence) were devoid of hyaluronate lyase activity whereas all ST25 (intermediate virulence) and ST28 (low virulence) isolates possessed the activity. A 2 bp insertion was responsible for the lack of activity in ST1 strains. Since the most virulent isolates did not degrade hyaluronic acid, this tissue component may be found during the infectious process. Therefore, we investigated its effect on S. suis and host cells. Hyaluronic acid was found to modulate S. suis adhesion to BMEC, to increase S. suis virulence factor expression, and to enhance pro-inflammatory cytokine secretion by BMEC. These findings suggest that S. suis hyaluronate lyase does not represent a critical virulence factor in its active form. However, exogenous hyaluronic acid that is likely to interact with S. suis and host cells during the course of infection appears to modulate several virulence determinants of the bacterium, in addition to promote inflammation.

  12. Clinical resistance and decreased susceptibility in Streptococcus suis isolates from clinically healthy fattening pigs.

    PubMed

    Callens, Bénédicte F; Haesebrouck, Freddy; Maes, Dominiek; Butaye, Patrick; Dewulf, Jeroen; Boyen, Filip

    2013-04-01

    Streptococcus suis (S. suis) has often been reported as an important swine pathogen and is considered as a new emerging zoonotic agent. Consequently, it is important to be informed on its susceptibility to antimicrobial agents. In the current study, the Minimum Inhibitory Concentration (MIC) population distribution of nine antimicrobial agents has been determined for nasal S. suis strains, isolated from healthy pigs at the end of the fattening period from 50 closed or semiclosed pig herds. The aim of the study was to report resistance based on both clinical breakpoints (clinical resistance percentage) and epidemiological cutoff values (non-wild-type percentage). Non-wild-type percentages were high for tetracycline (98%), lincomycin (92%), tilmicosin (72%), erythromycin (70%), tylosin (66%), and low for florfenicol (0%) and enrofloxacin (0.3%). Clinical resistance percentages were high for tetracycline (95%), erythromycin (66%), tylosin (66%), and low for florfenicol (0.3%) and enrofloxacin (0.3%). For tiamulin, for which no clinical breakpoint is available, 57% of the isolates did not belong to the wild-type population. Clinical resistance and non-wild-type percentages differed substantially for penicillin. Only 1% of the tested S. suis strains was considered as clinically resistant, whereas 47% of the strains showed acquired resistance when epidemiological cutoff values were used. In conclusion, MIC values for penicillin are gradually increasing, compared to previous reports, although pigs infected with strains showing higher MICs may still respond to treatment with penicillin. The high rate of acquired resistance against tiamulin has not been reported before. Results from this study clearly demonstrate that the use of different interpretive criteria contributes to the extent of differences in reported antimicrobial resistance results. The early detection of small changes in the MIC population distribution of isolates, while clinical failure may not yet be

  13. Monitoring of antimicrobial susceptibility of Streptococcus suis in the Netherlands, 2013-2015.

    PubMed

    van Hout, Jobke; Heuvelink, Annet; Gonggrijp, Maaike

    2016-10-15

    The objective of the present study was to analyse the in vitro antimicrobial susceptibility of Streptococcus suis isolates from post-mortem samples from pigs in the Netherlands. S. suis isolates originated from diagnostic submissions of pigs sent to the Pathology Department of GD Animal Health, from April 2013 till June 2015. Minimal inhibitory concentrations (MICs) of in total 15 antimicrobials were assessed by broth microdilution following CLSI recommendations. MIC50 and MIC90 values were determined and MICs were interpreted as susceptible, intermediate and resistant using CLSI veterinary breakpoints (when available). Emergence of resistance among S. suis (n=1163) derived from clinical submissions of pigs appeared to be limited. Resistance to ampicillin, ceftiofur, clindamycin, enrofloxacin, florfenicol, penicillin, trimethoprim/sulfamethoxazole and tetracycline was 0.3%, 0.5%, 48.1%, 0.6%, 0.1%, 0.5%, 3.0%, and 78.4%, respectively. Cross-resistance between penicillin and ampicillin appeared to be incomplete. MIC values of erythromycin, clindamycin, neomycin, penicillin and tilmicosin for isolates originating from grower/finisher pigs were significantly more often lower than the MIC values of isolates from suckling/weaned piglets. It has to be kept in mind that these results represent only part of the Dutch pig population and it can be discussed whether this is a representative sample. Interpretation of the MIC results of (clinically relevant) antimicrobials tested for treatment of S. suis infection is strongly hampered by the lack of CLSI-defined veterinary clinical breakpoints that are animal species- and body site-specific. Therefore, and to conduct a clinically reliable monitoring of antimicrobial susceptibility of veterinary pathogens, more species- and organ-specific veterinary breakpoints are urgently needed.

  14. Temporal and spatial association of Streptococcus suis infection in humans and porcine reproductive and respiratory syndrome outbreaks in pigs in northern Vietnam.

    PubMed

    Huong, V T L; Thanh, L V; Phu, V D; Trinh, D T; Inui, K; Tung, N; Oanh, N T K; Trung, N V; Hoa, N T; Bryant, J E; Horby, P W; Kinh, N V; Wertheim, H F L

    2016-01-01

    Porcine reproductive and respiratory syndrome (PRRS) outbreaks in pigs are associated with increased susceptibility of pigs to secondary bacterial infections, including Streptococcus suis - an important zoonotic pathogen causing bacterial meningitis in humans. This case-control study examined the association between human S. suis infection and PRRS outbreaks in pigs in northern Vietnam. We included 90 S. suis case-patients and 183 non-S. suis sepsis controls from a referral hospital in Hanoi in 2010, a period of major PRRS epizootics in Vietnam. PRRS exposure was determined using data from the National Centre of Veterinary Diagnosis. By univariate analysis, significantly more S. suis patients were reported residing in or adjacent to a PRRS district compared to controls [odds ratio (OR) 2·82, 95% confidence interval (CI) 1·35-5·89 and OR 3·15, 95% CI 1·62-6·15, respectively]. Only residency in adjacent districts remained significantly associated with risk of S. suis infection after adjusting for sex, occupation, and eating practices. SaTScan analysis showed a possible cluster of S. suis infection in humans around PRRS confirmed locations during the March-August period. The findings indicate an epidemiological association between PRRS in pigs and S. suis infections in humans. Effective strategies to strengthen control of PRRS in pigs may help reduce transmission of S. suis infection to humans.

  15. Molecular pathogenicity of Streptococcus anginosus.

    PubMed

    Asam, D; Spellerberg, B

    2014-08-01

    Streptococcus anginosus and the closely related species Streptococcus constellatus and Streptococcus intermedius, are primarily commensals of the mucosa. The true pathogenic potential of this group has been under-recognized for a long time because of difficulties in correct species identification as well as the commensal nature of these species. In recent years, streptococci of the S. anginosus group have been increasingly found as relevant microbial pathogens in abscesses and blood cultures and they play a pathogenic role in cystic fibrosis. Several international studies have shown a surprisingly high frequency of infections caused by the S. anginosus group. Recent studies and a genome-wide comparative analysis suggested the presence of multiple putative virulence factors that are well-known from other streptococcal species. However, very little is known about the molecular basis of pathogenicity in these bacteria. This review summarizes our current knowledge of pathogenicity factors and their regulation in S. anginosus.

  16. Evolution and Diversity of the Antimicrobial Resistance Associated Mobilome in Streptococcus suis: A Probable Mobile Genetic Elements Reservoir for Other Streptococci.

    PubMed

    Huang, Jinhu; Ma, Jiale; Shang, Kexin; Hu, Xiao; Liang, Yuan; Li, Daiwei; Wu, Zuowei; Dai, Lei; Chen, Li; Wang, Liping

    2016-01-01

    Streptococcus suis is a previously neglected, newly emerging multidrug-resistant zoonotic pathogen. Mobile genetic elements (MGEs) play a key role in intra- and interspecies horizontal transfer of antimicrobial resistance (AMR) determinants. Although, previous studies showed the presence of several MGEs, a comprehensive analysis of AMR-associated mobilome as well as their interaction and evolution has not been performed. In this study, we presented the AMR-associated mobilome and their insertion hotspots in S. suis. Integrative conjugative elements (ICEs), prophages and tandem MGEs were located at different insertion sites, while 86% of the AMR-associated MGEs were inserted at rplL and rum loci. Comprehensive analysis of insertions at rplL and rum loci among four pathogenic Streptococcus species (Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes, and S. suis) revealed the existence of different groups of MGEs, including Tn5252, ICESp1108, and TnGBS2 groups ICEs, Φm46.1 group prophage, ICE_ICE and ICE_prophage tandem MGEs. Comparative ICE genomics of ICESa2603 family revealed that module exchange and acquisition/deletion were the main mechanisms in MGEs' expansion and evolution. Furthermore, the observation of tandem MGEs reflected a novel mechanism for MGE diversity. Moreover, an in vitro competition assay showed no visible fitness cost was observed between different MGE-carrying isolates and a conjugation assay revealed the transferability of ICESa2603 family of ICEs. Our statistics further indicated that the prevalence and diversity of MGEs in S. suis is much greater than in other three species which prompted our hypothesis that S. suis is probably a MGEs reservoir for other streptococci. In conclusion, our results showed that acquisition of MGEs confers S. suis not only its capability as a multidrug resistance pathogen, but also represents a paradigm to study the modular evolution and matryoshkas of MGEs.

  17. Subtilisin-like protease-1 secreted through type IV secretion system contributes to high virulence of Streptococcus suis 2

    PubMed Central

    Yin, Supeng; Li, Ming; Rao, Xiancai; Yao, Xinyue; Zhong, Qiu; Wang, Min; Wang, Jing; Peng, Yizhi; Tang, Jiaqi; Hu, Fuquan; Zhao, Yan

    2016-01-01

    Streptococcus suis serotype 2 is an emerging zoonotic pathogen that triggered two outbreaks of streptococcal toxic shock syndrome (STSS) in China. Our previous research demonstrated that a type IV secretion system (T4SS) harbored in the 89K pathogenicity island contributes to the pathogenicity of S. suis 2. In the present study, a shotgun proteomics approach was employed to identify the effectors secreted by T4SS in S. suis 2, and surface-associated subtilisin-like protease-1 (SspA-1) was identified as a potential virulence effector. Western blot analysis and pull-down assay revealed that SspA-1 secretion depends on T4SS. Knockout mutations affecting sspA-1 attenuated S. suis 2 and impaired the pathogen’s ability to trigger inflammatory response in mice. And purified SspA-1 induced the secretion of IL-6, TNF-α, and IL-12p70 in THP-1 cells directly. SspA-1 is the first T4SS virulence effector reported in Gram-positive bacteria. Overall, these findings allow us to gain further insights into the pathogenesis of T4SS and STSS. PMID:27270879

  18. An emerging zoonotic clone in the Netherlands provides clues to virulence and zoonotic potential of Streptococcus suis

    PubMed Central

    Willemse, N.; Howell, K. J.; Weinert, L. A.; Heuvelink, A.; Pannekoek, Y.; Wagenaar, J. A.; Smith, H. E.; van der Ende, A.; Schultsz, C.

    2016-01-01

    Streptococcus suis is a zoonotic swine pathogen and a major public health concern in Asia, where it emerged as an important cause of bacterial meningitis in adults. While associated with food-borne transmission in Asia, zoonotic S. suis infections are mainly occupational hazards elsewhere. To identify genomic differences that can explain zoonotic potential, we compared whole genomes of 98 S. suis isolates from human patients and pigs with invasive disease in the Netherlands, and validated our observations with 18 complete and publicly available sequences. Zoonotic isolates have smaller genomes than non-zoonotic isolates, but contain more virulence factors. We identified a zoonotic S. suis clone that diverged from a non-zoonotic clone by means of gene loss, a capsule switch, and acquisition of a two-component signalling system in the late 19th century, when foreign pig breeds were introduced. Our results indicate that zoonotic potential of S. suis results from gene loss, recombination and horizontal gene transfer events. PMID:27381348

  19. Mitogenic effect contributes to increased virulence of Streptococcus suis sequence type 7 to cause streptococcal toxic shock-like syndrome.

    PubMed

    Zheng, H; Ye, C; Segura, M; Gottschalk, M; Xu, J

    2008-09-01

    Streptococcus suis serotype 2 sequence type 7 strains emerged in 1996 and caused a streptococcal toxic shock-like syndrome in 1998 and 2005 in China. Evidence indicated that the virulence of S. suis sequence type 7 had increased, but the mechanism was unknown. The sequence type 7 strain SC84, isolated from a patient with streptococcal toxic shock-like syndrome during the Sichuan outbreak, and the sequence type 1 strain 31533, a typical highly pathogenic strain isolated from a diseased pig, were used in comparative studies. In this study we show the mechanisms underlying cytokine production differed between the two types of strains. The S. suis sequence type 7 strain SC84 possesses a stronger capacity to stimulate T cells, naive T cells and peripheral blood mononuclear cell proliferation than does S. suis sequence type 1 strain 31533. The T cell response to both strains was dependent upon the presence of antigen-presenting cells. Histo-incompatible antigen-presenting cells were sufficient to provide the accessory signals to naive T cell stimulated by the two strains, indicating that both sequence type 7 and 1 strains possess mitogens; however, the mitogenic effect was different. Therefore, we propose that the difference in the mitogenic effect of sequence type 7 strain SC84 compared with the sequence type 1 strain 31533 of S. suis may be associated with the clinical, epidemiological and microbiological difference, where the ST 7 strains have a larger mitogenic effect.

  20. Genotyping and investigating capsular polysaccharide synthesis gene loci of non-serotypeable Streptococcus suis isolated from diseased pigs in Canada.

    PubMed

    Zheng, Han; Qiu, Xiaotong; Roy, David; Segura, Mariela; Du, Pengchen; Xu, Jianguo; Gottschalk, Marcelo

    2017-02-20

    Streptococcus suis (S. suis) is an important swine pathogen and an emerging zoonotic agent. Most clinical S. suis strains express capsular polysaccharides (CPS), which can be typed by antisera using the coagglutination test. In this study, 79 S. suis strains recovered from diseased pigs in Canada and which could not be typed using antisera were further characterized by capsular gene typing and sequencing. Four patterns of cps locus were observed: (1) fifteen strains were grouped into previously reported serotypes but presented several mutations in their cps loci, when compared to available data from reference strains; (2) seven strains presented a complete deletion of the cps locus, which would result in an inability to synthesize capsule; (3) forty-seven strains were classified in recently described novel cps loci (NCLs); and (4) ten strains carried novel NCLs not previously described. Different virulence gene profiles (based on the presence of mrp, epf, and/or sly) were observed in these non-serotypeable strains. This study provides further insight in understanding the genetic characteristics of cps loci in non-serotypeable S. suis strains recovered from diseased animals. When using a combination of the previously described 35 serotypes and the complete NCL system, the number of untypeable strains recovered from diseased animals in Canada would be significantly reduced.

  1. Purification and Characterization of Suicin 65, a Novel Class I Type B Lantibiotic Produced by Streptococcus suis.

    PubMed

    Vaillancourt, Katy; LeBel, Geneviève; Frenette, Michel; Fittipaldi, Nahuel; Gottschalk, Marcelo; Grenier, Daniel

    2015-01-01

    Bacteriocins are antimicrobial peptides of bacterial origin that are considered as a promising alternative to the use of conventional antibiotics. Recently, our laboratory reported the purification and characterization of two lantibiotics, suicin 90-1330 and suicin 3908, produced by the swine pathogen and zoonotic agent Streptococcus suis (serotype 2). In this study, a novel bacteriocin produced by S. suis has been identified and characterized. The producing strain S. suis 65 (serotype 2) was found to belong to the sequence type 28, that includes strains known to be weakly or avirulent in a mouse model. The bacteriocin, whose production was only possible following growth on solid culture medium, was purified to homogeneity by cationic exchange and reversed-phase high-pressure liquid chromatography. The bacteriocin, named suicin 65, was heat, pH and protease resistant. Suicin 65 was active against all S. suis isolates tested, including antibiotic resistant strains. Amino acid sequencing of the purified bacteriocin by Edman degradation revealed the presence of modified amino acids suggesting a lantibiotic. Using the partial sequence obtained, a blast was performed against published genomes of S. suis and allowed to identify a putative lantibiotic locus in the genome of S. suis 89-1591. From this genome, primers were designed and the gene cluster involved in the production of suicin 65 by S. suis 65 was amplified by PCR. Sequence analysis revealed the presence of ten open reading frames, including a duplicate of the structural gene. The structural genes (sssA and sssA') of suicin 65 encodes a 25-amino acid residue leader peptide and a 26-amino acid residue mature peptide yielding an active bacteriocin with a deducted molecular mass of 3,005 Da. Mature suicin 65 showed a high degree of identity with class I type B lantibiotics (globular structure) produced by Streptococcus pyogenes (streptococcin FF22; 84.6%), Streptococcus macedonicus (macedocin ACA-DC 198; 84

  2. Purification and Characterization of Suicin 65, a Novel Class I Type B Lantibiotic Produced by Streptococcus suis

    PubMed Central

    Vaillancourt, Katy; LeBel, Geneviève; Frenette, Michel; Fittipaldi, Nahuel; Gottschalk, Marcelo; Grenier, Daniel

    2015-01-01

    Bacteriocins are antimicrobial peptides of bacterial origin that are considered as a promising alternative to the use of conventional antibiotics. Recently, our laboratory reported the purification and characterization of two lantibiotics, suicin 90–1330 and suicin 3908, produced by the swine pathogen and zoonotic agent Streptococcus suis (serotype 2). In this study, a novel bacteriocin produced by S. suis has been identified and characterized. The producing strain S. suis 65 (serotype 2) was found to belong to the sequence type 28, that includes strains known to be weakly or avirulent in a mouse model. The bacteriocin, whose production was only possible following growth on solid culture medium, was purified to homogeneity by cationic exchange and reversed-phase high-pressure liquid chromatography. The bacteriocin, named suicin 65, was heat, pH and protease resistant. Suicin 65 was active against all S. suis isolates tested, including antibiotic resistant strains. Amino acid sequencing of the purified bacteriocin by Edman degradation revealed the presence of modified amino acids suggesting a lantibiotic. Using the partial sequence obtained, a blast was performed against published genomes of S. suis and allowed to identify a putative lantibiotic locus in the genome of S. suis 89–1591. From this genome, primers were designed and the gene cluster involved in the production of suicin 65 by S. suis 65 was amplified by PCR. Sequence analysis revealed the presence of ten open reading frames, including a duplicate of the structural gene. The structural genes (sssA and sssA’) of suicin 65 encodes a 25-amino acid residue leader peptide and a 26-amino acid residue mature peptide yielding an active bacteriocin with a deducted molecular mass of 3,005 Da. Mature suicin 65 showed a high degree of identity with class I type B lantibiotics (globular structure) produced by Streptococcus pyogenes (streptococcin FF22; 84.6%), Streptococcus macedonicus (macedocin ACA-DC 198; 84

  3. Protection against Streptococcus suis Serotype 2 Infection Using a Capsular Polysaccharide Glycoconjugate Vaccine

    PubMed Central

    Calzas, Cynthia; Shiao, Tze Chieh; Neubauer, Axel; Kempker, Jennifer; Roy, René; Gottschalk, Marcelo

    2016-01-01

    Streptococcus suis serotype 2 is an encapsulated bacterium and one of the most important bacterial pathogens in the porcine industry. Despite decades of research for an efficient vaccine, none is currently available. Based on the success achieved with other encapsulated pathogens, a glycoconjugate vaccine strategy was selected to elicit opsonizing anti-capsular polysaccharide (anti-CPS) IgG antibodies. In this work, glycoconjugate prototypes were prepared by coupling S. suis type 2 CPS to tetanus toxoid, and the immunological features of the postconjugation preparations were evaluated in vivo. In mice, experiments evaluating three different adjuvants showed that CpG oligodeoxyribonucleotide (ODN) induces very low levels of anti-CPS IgM antibodies, while the emulsifying adjuvants Stimune and TiterMax Gold both induced high levels of IgGs and IgM. Dose-response trials comparing free CPS with the conjugate vaccine showed that free CPS is nonimmunogenic independently of the dose used, while 25 μg of the conjugate preparation was optimal in inducing high levels of anti-CPS IgGs postboost. With an opsonophagocytosis assay using murine whole blood, sera from immunized mice showed functional activity. Finally, the conjugate vaccine showed immunogenicity and induced protection in a swine challenge model. When conjugated and administered with emulsifying adjuvants, S. suis type 2 CPS is able to induce potent IgM and isotype-switched IgGs in mice and pigs, yielding functional activity in vitro and protection against a lethal challenge in vivo, all features of a T cell-dependent response. This study represents a proof of concept for the potential of glycoconjugate vaccines in veterinary medicine applications against invasive bacterial infections. PMID:27113360

  4. A novel suicide shuttle plasmid for Streptococcus suis serotype 2 and Streptococcus equi ssp. zooepidemicus gene mutation

    PubMed Central

    Liu, Rui; Zhang, Ping; Su, Yiqi; Lin, Huixing; Zhang, Hui; Yu, Lei; Ma, Zhe; Fan, Hongjie

    2016-01-01

    The mariner-based Himar1 system has been utilized for creating mutant libraries of many Gram-positive bacteria. Streptococcus suis serotype 2 (SS2) and Streptococcus equi ssp. zooepidemicus (SEZ) are primary pathogens of swine that threaten the swine industry in China. To provide a forward-genetics technology for finding virulent phenotype-related genes in these two pathogens, we constructed a novel temperature-sensitive suicide shuttle plasmid, pMar4s, which contains the Himar1 system transposon, TnYLB-1, and the Himar1 C9 transposase from pMarA and the repTAs temperature-sensitive fragment from pSET4s. The kanamycin (Kan) resistance gene was in the TnYLB-1 transposon. Temperature sensitivity and Kan resistance allowed the selection of mutant strains and construction of the mutant library. The SS2 and SEZ mutant libraries were successfully constructed using the pMar4s plasmid. Inverse-Polymerase Chain Reaction (Inverse-PCR) results revealed large variability in transposon insertion sites and that the library could be used for phenotype alteration screening. The thiamine biosynthesis gene apbE was screened for its influence on SS2 anti-phagocytosis; likewise, the sagF gene was identified to be a hemolytic activity-related gene in SEZ. pMar4s was suitable for mutant library construction, providing more information regarding SS2 and SEZ virulence factors and illustrating the pathogenesis of swine streptococcosis. PMID:27256117

  5. Crystallization and preliminary crystallographic analysis of recombinant immunoglobulin G-binding protein from Streptococcus suis

    SciTech Connect

    Khan, Abdul Hamid; Chu, Fuliang; Feng, Youjun; Zhang, Qinagmin; Qi, Jianxun; Gao, George Fu

    2008-08-01

    Crystallization of recombinant IgG-binding protein expressed in Escherichia coli using the hanging-drop vapour-diffusion method is described. The crystals belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 38.98, b = 43.94, c = 78.17 Å. Streptococcus suis, an important zoonotic pathogen, expresses immunoglobulin G-binding protein, which is thought to be helpful to the organism in eluding the host defence system. Recombinant IgG-binding protein expressed in Escherichia coli has been crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 38.98, b = 43.94, c = 78.17 Å and one molecule in the asymmetric unit. Diffraction data were collected to 2.60 Å resolution.

  6. Functional and Structural Characterization of the Antiphagocytic Properties of a Novel Transglutaminase from Streptococcus suis*

    PubMed Central

    Yu, Jie; Pian, Yaya; Ge, Jingpeng; Guo, Jie; Zheng, Yuling; Jiang, Hua; Hao, Huaijie; Yuan, Yuan; Jiang, Yongqiang; Yang, Maojun

    2015-01-01

    Streptococcus suis serotype 2 (Ss2) is an important swine and human zoonotic pathogen. In the present study, we identified a novel secreted immunogenic protein, SsTGase, containing a highly conserved eukaryotic-like transglutaminase (TGase) domain at the N terminus. We found that inactivation of SsTGase significantly reduced the virulence of Ss2 in a pig infection model and impaired its antiphagocytosis in human blood. We further solved the crystal structure of the N-terminal portion of the protein in homodimer form at 2.1 Å. Structure-based mutagenesis and biochemical studies suggested that disruption of the homodimer directly resulted in the loss of its TGase activity and antiphagocytic ability. Characterization of SsTGase as a novel virulence factor of Ss2 by acting as a TGase would be beneficial for developing new therapeutic agents against Ss2 infections. PMID:26085092

  7. Slaughterhouse pigs are a major reservoir of Streptococcus suis serotype 2 capable of causing human infection in southern Vietnam.

    PubMed

    Ngo, Thi Hoa; Tran, Thi Bich Chieu; Tran, Thi Thu Nga; Nguyen, Van Dung; Campbell, James; Pham, Hong Anh; Huynh, Huu Tho; Nguyen, Van Vinh Chau; Bryant, Juliet E; Tran, Tinh Hien; Farrar, Jeremy; Schultsz, Constance

    2011-03-28

    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, we determined the prevalence and diversity of S. suis carriage in healthy slaughterhouse pigs. Nasopharyngeal tonsils were sampled from pigs at slaughterhouses serving six provinces in southern Vietnam and Ho Chi Minh City area from September 2006 to November 2007. Samples were screened by bacterial culture. Isolates of S. suis were serotyped and characterized by multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE). Antibiotic susceptibility profiles and associated genetic resistance determinants, and the presence of putative virulence factors were determined. 41% (222/542) of pigs carried S. suis of one or multiple serotypes. 8% (45/542) carried S. suis serotype 2 which was the most common serotype found (45/317 strains, 14%). 80% of serotype 2 strains belonged to the MLST clonal complex 1,which was previously associated with meningitis cases in Vietnam and outbreaks of severe disease in China in 1998 and 2005. These strains clustered with representative strains isolated from patients with meningitis in PFGE analysis, and showed similar antimicrobial resistance and virulence factor profiles. Slaughterhouse pigs are a major reservoir of S. suis serotype 2 capable of causing human infection in southern Vietnam. Strict hygiene at processing facilities, and health education programs addressing food safety and proper handling of pork should be encouraged.

  8. Slaughterhouse Pigs Are a Major Reservoir of Streptococcus suis Serotype 2 Capable of Causing Human Infection in Southern Vietnam

    PubMed Central

    Hoa, Ngo Thi; Chieu, Tran Thi Bich; Nga, Tran Thi Thu; Dung, Nguyen Van; Campbell, James; Anh, Pham Hong; Huu Tho, Huynh; Van Vinh Chau, Nguyen; Bryant, Juliet E.; Hien, Tran Tinh; Farrar, Jeremy; Schultsz, Constance

    2011-01-01

    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, we determined the prevalence and diversity of S. suis carriage in healthy slaughterhouse pigs. Nasopharyngeal tonsils were sampled from pigs at slaughterhouses serving six provinces in southern Vietnam and Ho Chi Minh City area from September 2006 to November 2007. Samples were screened by bacterial culture. Isolates of S. suis were serotyped and characterized by multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE). Antibiotic susceptibility profiles and associated genetic resistance determinants, and the presence of putative virulence factors were determined. 41% (222/542) of pigs carried S. suis of one or multiple serotypes. 8% (45/542) carried S. suis serotype 2 which was the most common serotype found (45/317 strains, 14%). 80% of serotype 2 strains belonged to the MLST clonal complex 1,which was previously associated with meningitis cases in Vietnam and outbreaks of severe disease in China in 1998 and 2005. These strains clustered with representative strains isolated from patients with meningitis in PFGE analysis, and showed similar antimicrobial resistance and virulence factor profiles. Slaughterhouse pigs are a major reservoir of S. suis serotype 2 capable of causing human infection in southern Vietnam. Strict hygiene at processing facilities, and health education programs addressing food safety and proper handling of pork should be encouraged. PMID:21464930

  9. MsmK, an ATPase, Contributes to Utilization of Multiple Carbohydrates and Host Colonization of Streptococcus suis.

    PubMed

    Tan, Mei-Fang; Gao, Ting; Liu, Wan-Quan; Zhang, Chun-Yan; Yang, Xi; Zhu, Jia-Wen; Teng, Mu-Ye; Li, Lu; Zhou, Rui

    2015-01-01

    Acquisition and metabolism of carbohydrates are essential for host colonization and pathogenesis of bacterial pathogens. Different bacteria can uptake different lines of carbohydrates via ABC transporters, in which ATPase subunits energize the transport though ATP hydrolysis. Some ABC transporters possess their own ATPases, while some share a common ATPase. Here we identified MsmK, an ATPase from Streptococcus suis, an emerging zoonotic bacterium causing dead infections in pigs and humans. Genetic and biochemistry studies revealed that the MsmK was responsible for the utilization of raffinose, melibiose, maltotetraose, glycogen and maltotriose. In infected mice, the msmK-deletion mutant showed significant defects of survival and colonization when compared with its parental and complementary strains. Taken together, MsmK is an ATPase that contributes to multiple carbohydrates utilization and host colonization of S. suis. This study gives new insight into our understanding of the carbohydrates utilization and its relationship to the pathogenesis of this zoonotic pathogen.

  10. MsmK, an ATPase, Contributes to Utilization of Multiple Carbohydrates and Host Colonization of Streptococcus suis

    PubMed Central

    Tan, Mei-Fang; Gao, Ting; Liu, Wan-Quan; Zhang, Chun-Yan; Yang, Xi; Zhu, Jia-Wen; Teng, Mu-Ye; Li, Lu; Zhou, Rui

    2015-01-01

    Acquisition and metabolism of carbohydrates are essential for host colonization and pathogenesis of bacterial pathogens. Different bacteria can uptake different lines of carbohydrates via ABC transporters, in which ATPase subunits energize the transport though ATP hydrolysis. Some ABC transporters possess their own ATPases, while some share a common ATPase. Here we identified MsmK, an ATPase from Streptococcus suis, an emerging zoonotic bacterium causing dead infections in pigs and humans. Genetic and biochemistry studies revealed that the MsmK was responsible for the utilization of raffinose, melibiose, maltotetraose, glycogen and maltotriose. In infected mice, the msmK-deletion mutant showed significant defects of survival and colonization when compared with its parental and complementary strains. Taken together, MsmK is an ATPase that contributes to multiple carbohydrates utilization and host colonization of S. suis. This study gives new insight into our understanding of the carbohydrates utilization and its relationship to the pathogenesis of this zoonotic pathogen. PMID:26222651

  11. Prevalence of the suilysin gene in Streptococcus suis strains isolated from diseased and healthy carrier pigs.

    PubMed

    Fabisiak, M; Kita, J; Jedryczko, R; Binek, M

    2005-01-01

    Knowledge of virulence factors of Streptococcus suis is limited. Several virulence factor candidates have been proposed, among them suilysin, which is responsible for a toxic effect on epithelial cells. The aim of this study was to detect the suilysin gene sequence in Streptococcus suis strains of various origin. In total 63 Streptococcus suis isolates were investigated. Forty four of them originated from tissues of streptococcosis affected animals. The remaining 19 strains were isolated from tonsils of healthy carrier pigs. Suilysin gene specific sequence was detected in 79% of the strains tested. In isolates obtained from pigs with signs of streptococcosis this gene sequence was recorded in 85% of cases. In Streptococcus suis strains isolated from healthy carrier pigs the suilysin gene was detected in 63% of the isolates. It seems that suilysin toxic activity is only one of the many steps involved in the pathogenesis of Streptococcus suis infection and that strain's virulence cannot be stated only on the basis of suilysin gene sequence presence.

  12. The involvement of MsmK in pathogenesis of the Streptococcus suis serotype 2.

    PubMed

    Tan, Mei-Fang; Liu, Wan-Quan; Zhang, Chun-Yan; Gao, Ting; Zheng, Lin-Lin; Qiu, De-Xin; Li, Lu; Zhou, Rui

    2017-04-01

    Streptococcus suis serotype 2 (SS2) is an important swine and human pathogen that causes global economic and public health problems. Virulent S. suis strains successfully maintain high bacterial concentrations in host blood and rapidly adapt to challenging environments within hosts. Successful survival in hosts is a major factor influencing the pathogenesis of SS2. We have previously identified that SS2 colonization in mouse brain is possibly affected by the ATPase, MsmK of carbohydrate ATP-binding cassette (ABC) transporters because of carbohydrate utilization. In this study, the chain length of the msmK deletion mutant was longer than that of the wild type, and the former was significantly more susceptible than the latter when theses strains were exposed to mouse blood both in vivo and in vitro. The hemolytic activity of the mutant strain was decreased. Although the adhesion of the mutant to HEp-2 cell lines was enhanced, the deletion of msmK impaired the abilities of SS2 to resist phagocytosis and survive severe stress conditions. MsmK contributed to the survival and adaptation of SS2 in host bloodstream. Therefore, MsmK was identified as a multifunctional component that not only contributed to carbohydrate utilization but also participated in SS2 pathogenesis. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  13. Characterization and Functional Analysis of atl, a Novel Gene Encoding Autolysin in Streptococcus suis

    PubMed Central

    Ju, Cun-Xiang; Gu, Hong-Wei

    2012-01-01

    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 fibronectin-binding activities were confirmed by zymography and Western affinity blotting. Two bacteriolytic bands were shown in the sodium dodecyl sulfate extracts of HA9801, while both were absent from the atl inactivated mutant. Cell chains of the mutant strain became longer than that of the parental strain. In the autolysis assay, HA9801 decreased to 20% of the initial optical density (OD) value, while the mutant strain had almost no autolytic activity. The biofilm capacity of the atl mutant was reduced ∼30% compared to the parental strain. In the zebrafish infection model, the 50% lethal dose of the mutant strain was increased up to 5-fold. Furthermore, the adherence to HEp-2 cells of the atl mutant was 50% less than that of the parental strain. Based on the functional analysis of the recombinant Atl and observed effects of atl inactivation on HA9801, we conclude that Atl is a major autolysin of HA9801. It takes part in cell autolysis, separation of daughter cells, biofilm formation, fibronectin-binding activity, cell adhesion, and pathogenesis of HA9801. PMID:22228730

  14. Antimicrobial Resistance Profile and Genotypic Characteristics of Streptococcus suis Capsular Type 2 Isolated from Clinical Carrier Sows and Diseased Pigs in China

    PubMed Central

    Zhang, Chunping; Zhang, Zhongqiu; Song, Li; Fan, Xuezheng; Wen, Fang; Xu, Shixin; Ning, Yibao

    2015-01-01

    Streptococcus suis serotype 2 is an important zoonotic pathogen. Antimicrobial resistance phenotypes and genotypic characterizations of S. suis 2 from carrier sows and diseased pigs remain largely unknown. In this study, 96 swine S. suis type 2, 62 from healthy sows and 34 from diseased pigs, were analyzed. High frequency of tetracycline resistance was observed, followed by sulfonamides. The lowest resistance of S. suis 2 for β-lactams supports their use as the primary antibiotics to treat the infection of serotype 2. In contrast, 35 of 37 S. suis 2 with MLSB phenotypes were isolated from healthy sows, mostly encoded by the ermB and/or the mefA genes. Significantly lower frequency of mrp+/epf+/sly+ was observed among serotype 2 from healthy sows compared to those from diseased pigs. Furthermore, isolates from diseased pigs showed more homogeneously genetic patterns, with most of them clustered in pulsotypes A and E. The data indicate the genetic complexity of S. suis 2 between herds and a close linkage among isolates from healthy sows and diseased pigs. Moreover, many factors, such as extensive use of tetracycline or diffusion of Tn916 with tetM, might have favored for the pathogenicity and widespread dissemination of S. suis serotype 2. PMID:26064892

  15. Evaluation of the immunogenicity and the protective efficacy of a novel identified immunogenic protein, SsPepO, of Streptococcus suis serotype 2.

    PubMed

    Li, Jinquan; Xia, Jin; Tan, Chen; Zhou, Yang; Wang, Yan; Zheng, Chengkun; Chen, Huanchun; Bei, Weicheng

    2011-09-02

    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 protective efficacy of SsPepO in animal models, the recombinant SsPepO protein was used to immunize mice and pigs. The results demonstrated that it could elicit a strong humoral antibody response and confer significant protection against challenge with a lethal dose of S. suis 2 in mice and pig models. In addition, the antisera against rSsPepO could efficiently inhibit bacterial growth in a whole blood assay and conferred significant protection against S. suis 2 infection in passive immunization experiments. Our findings suggest that SsPepO plays an important role in the pathogenesis of S. suis 2 and would be a promising subunit vaccine candidate. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Sub-MICs of Azithromycin Decrease Biofilm Formation of Streptococcus suis and Increase Capsular Polysaccharide Content of S. suis

    PubMed Central

    Yang, Yan-Bei; Chen, Jian-Qing; Zhao, Yu-Lin; Bai, Jing-Wen; Ding, Wen-Ya; Zhou, Yong-Hui; Chen, Xue-Ying; Liu, Di; Li, Yan-Hua

    2016-01-01

    Streptococcus suis (S. suis) caused serious disease symptoms in humans and pigs. S. suis is able to form thick biofilms and this increases the difficulty of treatment. After growth with 1/2 minimal inhibitory concentration (MIC) of azithromycin, 1/4 MIC of azithromycin, or 1/8 MIC of azithromycin, biofilm formation of S. suis dose-dependently decreased in the present study. Furthermore, scanning electron microscopy analysis revealed the obvious effect of azithromycin against biofilm formation of S. suis. Especially, at two different conditions (1/2 MIC of azithromycin non-treated cells and treated cells), we carried out comparative proteomic analyses of cells by using iTRAQ technology. Finally, the results revealed the existence of 19 proteins of varying amounts. Interestingly, several cell surface proteins (such as ATP-binding cassette superfamily ATP-binding cassette transporter (G7SD52), CpsR (K0FG35), Cps1/2H (G8DTL7), CPS16F (E9NQ13), putative uncharacterized protein (G7SER0), NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (G5L259), putative uncharacterized protein (G7S2D6), amino acid permease (B0M0G6), and NsuB (G5L351)) were found to be implicated in biofilm formation. More importantly, we also found that azithromycin affected expression of the genes cps1/2H, cpsR and cps16F. Especially, after growth with 1/2 MIC of azithromycin and 1/4 MIC of azithromycin, the capsular polysaccharide content of S. suis was significantly higher. PMID:27812354

  17. Streptococcus suis Meningoencephalitis with Seizure from Raw Pork Ingestion: A Case Report

    PubMed Central

    Teerasukjinda, Ornusa; Yee, Melvin; Chung, Heath H

    2014-01-01

    Background: Streptococcus suis meningoencephalitis is a rare but increasingly important condition. Good history taking will give clues to the diagnosis. This is the fourth case report in the United States. Case: A 52-year-old Filipino man who recently returned from a trip to the Philippines was admitted with classic symptoms of bacterial meningitis. His cerebrospinal fluid culture grew Streptococcus suis. His clinical course was complicated by seizures, hearing loss, and permanent tinnitus. Conclusion: Clinicians should be aware of this emerging disease especially in patients with recent travel history to endemic areas. Early recognition and appropriate management could potentially prevent complications. PMID:25285249

  18. The antimicrobial resistance patterns and associated determinants in Streptococcus suis isolated from humans in southern Vietnam, 1997-2008

    PubMed Central

    2011-01-01

    Background 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. Methods S. suis strains isolated between 1997 and 2008 were investigated for their susceptibility to six antimicrobial agents. Strains were screened for the presence and expression of tetracycline and erythromycin resistance determinants and the association of tet(M) genes with Tn916- like transposons. The localization of tetracycline resistance gene tet(L) was determined by pulse field gel electrophoresis and Southern blotting. Results We observed a significant increase in resistance to tetracycline and chloramphenicol, which was concurrent with an increase in multi-drug resistance. In tetracycline resistance strains, we identified tet(M), tet(O), tet(W) and tet(L) and confirmed their expression. All tet(M) genes were associated with a Tn916-like transposon. The co-expression of tet(L) and other tetracycline resistance gene(s) encoding for ribosomal protection protein(s) was only detected in strains with a minimum inhibitory concentration (MIC) of tetracycline of ≥ 64 mg/L Conclusions We demonstrated that multi-drug resistance in S. suis causing disease in humans in southern Vietnam has increased over the 11-year period studied. We report the presence and expression of tet(L) in S. suis strains and our data suggest that co-expression of multiple genes encoding distinct mechanism is required for an MIC ≥ 64 mg/L to tetracycline. PMID:21208459

  19. Immunogenicity of an Autogenous Streptococcus suis Bacterin in Preparturient Sows and Their Piglets in Relation to Protection after Weaning▿ †

    PubMed Central

    Baums, Christoph Georg; Brüggemann, Christian; Kock, Christoph; Beineke, Andreas; Waldmann, Karl-Heinz; Valentin-Weigand, Peter

    2010-01-01

    Streptococcus suis is an important porcine pathogen causing meningitis and other invasive diseases in piglets of different ages. Application of S. suis serotype 2 bacterins to specific-pathogen-free (SPF) weaning piglets has been demonstrated to protect against the homologous serotype. However, autogenous S. suis bacterins are also applied to sows and suckling piglets in the field. Therefore, comparative evaluation of different bacterin immunization regimes, including sow vaccination, was performed in this study. The main objectives were to determine the immunogenicity of an S. suis bacterin in sows prepartum and its influence on active immunization of piglets. Experimental infection of 6- and 8-week-old weaning piglets was performed to elucidate protective efficacies. Humoral immune responses were investigated by an enzyme-linked immunosorbent assay (ELISA) measuring muramidase-released protein (MRP)-specific IgG titers and by opsonophagocytosis assays. Bacterin application elicited high MRP-specific IgG titers in the serum and colostrum of sows, as well as opsonizing antibodies. Piglets from vaccinated sows had significantly higher MRP-specific titers than respective piglets from nonvaccinated sows until 6 weeks postpartum. Vaccination of suckling piglets did not result in high MRP-specific titers nor in induction of opsonizing antibodies. Furthermore, neither vaccination of suckling nor of weaning piglets from immunized sows was associated with a prominent active immune response and protection at 8 weeks postpartum. However, protection was observed in respective 6-week-old weaning piglets, most likely because of protective maternal immunity. In conclusion, this study provides the first results suggesting protective passive maternal immunity for S. suis serotype 2 after bacterin vaccination of sows and a strong inhibitory effect on active immunization of suckling and weaning piglets, leading to highly susceptible growers. PMID:20739502

  20. Surveillance of antimicrobial resistance in clinical isolates of Pasteurella multocida and Streptococcus suis from Ontario swine.

    PubMed

    Glass-Kaastra, Shiona K; Pearl, David L; Reid-Smith, Richard J; McEwen, Beverly; Slavic, Durda; Fairles, Jim; McEwen, Scott A

    2014-10-01

    Susceptibility results for Pasteurella multocida and Streptococcus suis isolated from swine clinical samples were obtained from January 1998 to October 2010 from the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, and used to describe variation in antimicrobial resistance (AMR) to 4 drugs of importance in the Ontario swine industry: ampicillin, tetracycline, tiamulin, and trimethoprim-sulfamethoxazole. Four temporal data-analysis options were used: visualization of trends in 12-month rolling averages, logistic-regression modeling, temporal-scan statistics, and a scan with the "What's strange about recent events?" (WSARE) algorithm. The AMR trends varied among the antimicrobial drugs for a single pathogen and between pathogens for a single antimicrobial, suggesting that pathogen-specific AMR surveillance may be preferable to indicator data. The 4 methods provided complementary and, at times, redundant results. The most appropriate combination of analysis methods for surveillance using these data included temporal-scan statistics with a visualization method (rolling-average or predicted-probability plots following logistic-regression models). The WSARE algorithm provided interesting results for quality control and has the potential to detect new resistance patterns; however, missing data created problems for displaying the results in a way that would be meaningful to all surveillance stakeholders.

  1. Surveillance of antimicrobial resistance in clinical isolates of Pasteurella multocida and Streptococcus suis from Ontario swine

    PubMed Central

    Glass-Kaastra, Shiona K.; Pearl, David L.; Reid-Smith, Richard J.; McEwen, Beverly; Slavic, Durda; Fairles, Jim; McEwen, Scott A.

    2014-01-01

    Susceptibility results for Pasteurella multocida and Streptococcus suis isolated from swine clinical samples were obtained from January 1998 to October 2010 from the Animal Health Laboratory at the University of Guelph, Guelph, Ontario, and used to describe variation in antimicrobial resistance (AMR) to 4 drugs of importance in the Ontario swine industry: ampicillin, tetracycline, tiamulin, and trimethoprim–sulfamethoxazole. Four temporal data-analysis options were used: visualization of trends in 12-month rolling averages, logistic-regression modeling, temporal-scan statistics, and a scan with the “What’s strange about recent events?” (WSARE) algorithm. The AMR trends varied among the antimicrobial drugs for a single pathogen and between pathogens for a single antimicrobial, suggesting that pathogen-specific AMR surveillance may be preferable to indicator data. The 4 methods provided complementary and, at times, redundant results. The most appropriate combination of analysis methods for surveillance using these data included temporal-scan statistics with a visualization method (rolling-average or predicted-probability plots following logistic-regression models). The WSARE algorithm provided interesting results for quality control and has the potential to detect new resistance patterns; however, missing data created problems for displaying the results in a way that would be meaningful to all surveillance stakeholders. PMID:25355992

  2. Characterization of the pivotal carbon metabolism of Streptococcus suis serotype 2 under ex vivo and chemically defined in vitro conditions by isotopologue profiling.

    PubMed

    Willenborg, Jörg; Huber, Claudia; Koczula, Anna; Lange, Birgit; Eisenreich, Wolfgang; Valentin-Weigand, Peter; Goethe, Ralph

    2015-02-27

    Streptococcus suis is a neglected zoonotic pathogen that has to adapt to the nutritional requirements in the different host niches encountered during infection and establishment of invasive diseases. To dissect the central metabolic activity of S. suis under different conditions of nutrient availability, we performed labeling experiments starting from [(13)C]glucose specimens and analyzed the resulting isotopologue patterns in amino acids of S. suis grown under in vitro and ex vivo conditions. In combination with classical growth experiments, we found that S. suis is auxotrophic for Arg, Gln/Glu, His, Leu, and Trp in chemically defined medium. De novo biosynthesis was shown for Ala, Asp, Ser, and Thr at high rates and for Gly, Lys, Phe, Tyr, and Val at moderate or low rates, respectively. Glucose degradation occurred mainly by glycolysis and to a minor extent by the pentose phosphate pathway. Furthermore, the exclusive formation of oxaloacetate by phosphoenolpyruvate (PEP) carboxylation became evident from the patterns in de novo synthesized amino acids. Labeling experiments with S. suis grown ex vivo in blood or cerebrospinal fluid reflected the metabolic adaptation to these host niches with different nutrient availability; however, similar key metabolic activities were identified under these conditions. This points at the robustness of the core metabolic pathways in S. suis during the infection process. The crucial role of PEP carboxylation for growth of S. suis in the host was supported by experiments with a PEP carboxylase-deficient mutant strain in blood and cerebrospinal fluid.

  3. Identification and Characterization of IgdE, a Novel IgG-degrading Protease of Streptococcus suis with Unique Specificity for Porcine IgG*

    PubMed Central

    Spoerry, Christian; Seele, Jana; Valentin-Weigand, Peter; Baums, Christoph G.; von Pawel-Rammingen, Ulrich

    2016-01-01

    Streptococcus suis is a major endemic pathogen of pigs causing meningitis, arthritis, and other diseases. Zoonotic S. suis infections are emerging in humans causing similar pathologies as well as severe conditions such as toxic shock-like syndrome. Recently, we discovered an IdeS family protease of S. suis that exclusively cleaves porcine IgM and represents the first virulence factor described, linking S. suis to pigs as their natural host. Here we report the identification and characterization of a novel, unrelated protease of S. suis that exclusively targets porcine IgG. This enzyme, designated IgdE for immunoglobulin G-degrading enzyme of S. suis, is a cysteine protease distinct from previous characterized streptococcal immunoglobulin degrading proteases of the IdeS family and mediates efficient cleavage of the hinge region of porcine IgG with a high degree of specificity. The findings that all S. suis strains investigated possess the IgG proteolytic activity and that piglet serum samples contain specific antibodies against IgdE strongly indicate that the protease is expressed in vivo during infection and represents a novel and putative important bacterial virulence/colonization determinant, and a thus potential therapeutic target. PMID:26861873

  4. Identification of a cell wall-associated subtilisin-like serine protease involved in the pathogenesis of Streptococcus suis serotype 2.

    PubMed

    Hu, Qiaoyun; Liu, Peng; Yu, Zhengjun; Zhao, Gang; Li, Jun; Teng, Liu; Zhou, Mingguang; Bei, Weicheng; Chen, Huanchun; Jin, Meilin

    2010-01-01

    Streptococcus suis is an important swine and human pathogen, and also an emerging zoonotic agent. A surface-associated subtilisin-like serine protease (SspA) of S. suis was identified by screening a genomic expression library as fragments of this protein reacted most strongly with convalescent-phase pig sera. The sspA gene is present in 29 of 33 S. suis serotypes reference strains and is expressed on the surface of S. suis. Relative real-time quantitative PCR assay demonstrated that sspA mRNA expression in vivo was several thousand fold of that in vitro. A sspA(-) mutant was generated from a S. suis serotype 2 strain SC19 by allelic exchange. The mutant was not different from the wild type strain in subcellular structures and in hemolytic phenotype. However, the virulence of the sspA(-) mutant was markedly lower than the wild type in pigs as demonstrated in experimental infections. These data indicated that the surface-associated protein SspA is a conserved virulence factor of S. suis and is involved in the pathogenesis of S. suis.

  5. Characterization of the Pivotal Carbon Metabolism of Streptococcus suis Serotype 2 under ex Vivo and Chemically Defined in Vitro Conditions by Isotopologue Profiling*

    PubMed Central

    Willenborg, Jörg; Huber, Claudia; Koczula, Anna; Lange, Birgit; Eisenreich, Wolfgang; Valentin-Weigand, Peter; Goethe, Ralph

    2015-01-01

    Streptococcus suis is a neglected zoonotic pathogen that has to adapt to the nutritional requirements in the different host niches encountered during infection and establishment of invasive diseases. To dissect the central metabolic activity of S. suis under different conditions of nutrient availability, we performed labeling experiments starting from [13C]glucose specimens and analyzed the resulting isotopologue patterns in amino acids of S. suis grown under in vitro and ex vivo conditions. In combination with classical growth experiments, we found that S. suis is auxotrophic for Arg, Gln/Glu, His, Leu, and Trp in chemically defined medium. De novo biosynthesis was shown for Ala, Asp, Ser, and Thr at high rates and for Gly, Lys, Phe, Tyr, and Val at moderate or low rates, respectively. Glucose degradation occurred mainly by glycolysis and to a minor extent by the pentose phosphate pathway. Furthermore, the exclusive formation of oxaloacetate by phosphoenolpyruvate (PEP) carboxylation became evident from the patterns in de novo synthesized amino acids. Labeling experiments with S. suis grown ex vivo in blood or cerebrospinal fluid reflected the metabolic adaptation to these host niches with different nutrient availability; however, similar key metabolic activities were identified under these conditions. This points at the robustness of the core metabolic pathways in S. suis during the infection process. The crucial role of PEP carboxylation for growth of S. suis in the host was supported by experiments with a PEP carboxylase-deficient mutant strain in blood and cerebrospinal fluid. PMID:25575595

  6. Raw pig blood consumption and potential risk for Streptococcus suis infection, Vietnam.

    PubMed

    Huong, Vu Thi Lan; Hoa, Ngo Thi; Horby, Peter; Bryant, Juliet E; Van Kinh, Nguyen; Toan, Tran Khanh; Wertheim, Heiman F L

    2014-11-01

    We assessed consumption of raw pig blood, which is a risk factor for Streptococcus suis infection in Vietnam, by using a mix-method design. Factors associated with consumption included rural residency, age, sex, occupation, income, and marital status. We identified risk groups and practices and perceptions that should be targeted by communication programs.

  7. Clearance of Streptococcus suis in Stomach Contents of Differently Fed Growing Pigs.

    PubMed

    Warneboldt, Franziska; Sander, Saara J; Beineke, Andreas; Valentin-Weigand, Peter; Kamphues, Josef; Baums, Christoph Georg

    2016-08-06

    Streptococcus (S.) suis translocates across the intestinal barrier of piglets after intraintestinal application. Based on these findings, an oro-gastrointestinal infection route has been proposed. Thus, the objective of this study was to investigate the survival of S. suis in the porcine stomach. Whereas surviving bacteria of S. suis serotypes 2 and 9 were not detectable after 60 min of incubation in stomach contents with a comparatively high gastric pH of 5 due to feeding of fine pellets, the number of Salmonella Derby bacteria increased under these conditions. Further experiments confirmed the clearance of S. suis serotypes 2 and 9 within 30 min in stomach contents with a pH of 4.7 independently of the bacterial growth phase. Finally, an oral infection experiment was conducted, feeding each of 18 piglets a diet mixed with 10(10) CFU of S. suis serotype 2 or 9. Thorough bacteriological screenings of various mesenteric-intestinal lymph nodes and internal organs after different times of exposure did not lead to any detection of the orally applied challenge strains. In conclusion, the porcine stomach constitutes a very efficient barrier against oro-gastrointenstinal S. suis infections. Conditions leading to the passage of S. suis through the stomach remain to be identified.

  8. Clearance of Streptococcus suis in Stomach Contents of Differently Fed Growing Pigs

    PubMed Central

    Warneboldt, Franziska; Sander, Saara J.; Beineke, Andreas; Valentin-Weigand, Peter; Kamphues, Josef; Baums, Christoph Georg

    2016-01-01

    Streptococcus (S.) suis translocates across the intestinal barrier of piglets after intraintestinal application. Based on these findings, an oro-gastrointestinal infection route has been proposed. Thus, the objective of this study was to investigate the survival of S. suis in the porcine stomach. Whereas surviving bacteria of S. suis serotypes 2 and 9 were not detectable after 60 min of incubation in stomach contents with a comparatively high gastric pH of 5 due to feeding of fine pellets, the number of Salmonella Derby bacteria increased under these conditions. Further experiments confirmed the clearance of S. suis serotypes 2 and 9 within 30 min in stomach contents with a pH of 4.7 independently of the bacterial growth phase. Finally, an oral infection experiment was conducted, feeding each of 18 piglets a diet mixed with 1010 CFU of S. suis serotype 2 or 9. Thorough bacteriological screenings of various mesenteric-intestinal lymph nodes and internal organs after different times of exposure did not lead to any detection of the orally applied challenge strains. In conclusion, the porcine stomach constitutes a very efficient barrier against oro-gastrointenstinal S. suis infections. Conditions leading to the passage of S. suis through the stomach remain to be identified. PMID:27509526

  9. Recombination between Streptococcus suis ICESsu32457 and Streptococcus agalactiae ICESa2603 yields a hybrid ICE transferable to Streptococcus pyogenes.

    PubMed

    Marini, Emanuela; Palmieri, Claudio; Magi, Gloria; Facinelli, Bruna

    2015-07-09

    Integrative conjugative elements (ICEs) are mobile genetic elements that reside in the chromosome but retain the ability to undergo excision and to transfer by conjugation. Genes involved in drug resistance, virulence, or niche adaptation are often found among backbone genes as cargo DNA. We recently characterized in Streptococcus suis an ICE (ICESsu32457) carrying resistance genes [tet(O/W/32/O), tet(40), erm(B), aphA, and aadE] in the 15K unstable genetic element, which is flanked by two ∼1.3kb direct repeats. Remarkably, ∼1.3-kb sequences are conserved in ICESa2603 of Streptococcus agalactiae 2603V/R, which carry heavy metal resistance genes cadC/cadA and mer. In matings between S. suis 32457 (donor) and S. agalactiae 2603V/R (recipient), transconjugants were obtained. PCR experiments, PFGE, and sequence analysis of transconjugants demonstrated a tandem array between ICESsu32457 and ICESa2603. Matings between tandem array-containing S. agalactiae 2603V/R (donor) and Streptococcus pyogenes RF12 (recipient) yielded a single transconjugant containing a hybrid ICE, here named ICESa2603/ICESsu32457. The hybrid formed by recombination of the left ∼1.3-kb sequence of ICESsu32457 and the ∼1.3-kb sequence of ICESa2603. Interestingly, the hybrid ICE was transferable between S. pyogenes strains, thus demonstrating that it behaves as a conventional ICE. These findings suggest that both tandem arrays and hybrid ICEs may contribute to the evolution of antibiotic resistance in streptococci, creating novel mobile elements capable of disseminating new combinations of antibiotic resistance genes.

  10. Response of swine spleen to Streptococcus suis infection revealed by transcription analysis

    PubMed Central

    2010-01-01

    Astract Background Streptococcus suis serotype 2 (SS2), a major swine pathogen and an emerging zoonotic agent, has greatly challenged global public health. Systematical information about host immune response to the infection is important for understanding the molecular mechanism of diseases. Results 104 and 129 unique genes were significantly up-regulated and down-regulated in the spleens of pigs infected with SS2 (WT). The up-regulated genes were principally related to immune response, such as genes involved in inflammatory response; acute-phase/immune response; cell adhesion and response to stress. The down-regulated genes were mainly involved in transcription, transport, material and energy metabolism which were representative of the reduced vital activity of SS2-influenced cells. Only a few genes showed significantly differential expression when comparing avirulent isogenic strain (ΔHP0197) with mock-infected samples. Conclusions Our findings indicated that highly pathogenic SS2 could persistently induce cytokines mainly by Toll-like receptor 2 (TLR2) pathway, and the phagocytosis-resistant bacteria could induce high level of cytokines and secrete toxins to destroy deep tissues, and cause meningitis, septicaemia, pneumonia, endocarditis, and arthritis. PMID:20937098

  11. Comparative Genome Analyses of Streptococcus suis Isolates from Endocarditis Demonstrate Persistence of Dual Phenotypic Clones

    PubMed Central

    Tohya, Mari; Watanabe, Takayasu; Maruyama, Fumito; Arai, Sakura; Ota, Atsushi; Athey, Taryn B. T.; Fittipaldi, Nahuel; Nakagawa, Ichiro; Sekizaki, Tsutomu

    2016-01-01

    Many bacterial species coexist in the same niche as heterogeneous clones with different phenotypes; however, understanding of infectious diseases by polyphenotypic bacteria is still limited. In the present study, encapsulation in isolates of the porcine pathogen Streptococcus suis from persistent endocarditis lesions was examined. Coexistence of both encapsulated and unencapsulated S. suis isolates was found in 26 out of 59 endocarditis samples. The isolates were serotype 2, and belonged to two different sequence types (STs), ST1 and ST28. The genomes of each of the 26 pairs of encapsulated and unencapsulated isolates from the 26 samples were sequenced. The data showed that each pair of isolates had one or more unique nonsynonymous mutations in the cps gene, and the encapsulated and unencapsulated isolates from the same samples were closest to each other. Pairwise comparisons of the sequences of cps genes in 7 pairs of encapsulated and unencapsulated isolates identified insertion/deletions (indels) ranging from one to 104 bp in different cps genes of unencapsulated isolates. Capsule expression was restored in a subset of unencapsulated isolates by complementation in trans with cps expression vectors. Examination of gene content common to isolates indicated that mutation frequency was higher in ST28 pairs than in ST1 pairs. Genes within mobile genetic elements were mutation hot spots among ST28 isolates. Taken all together, our results demonstrate the coexistence of dual phenotype (encapsulated and unencapsulated) bacterial clones and suggest that the dual phenotypes arose independently in each farm by means of spontaneous mutations in cps genes. PMID:27433935

  12. A novel virulence-associated protein, vapE, in Streptococcus suis serotype 2.

    PubMed

    Ji, Xue; Sun, Yang; Liu, Jun; Zhu, Lingwei; Guo, Xuejun; Lang, Xulong; Feng, Shuzhang

    2016-03-01

    Streptococcus suis serotype 2 (SS2) is an important pathogen that affects pigs. However, neither its virulence nor its pathogenesis of infection has yet to be fully elucidated. The present study identifies a novel virulence‑associated protein E gene (vapE) of SS2. To investigate the importance of vapE in SS2 infection, a vapE knock‑out mutant based on SS2 wild‑type strain ZY458 was designated 458ΔvapE. 458ΔvapE was generated through homologous recombination, using a combined plasmid with a vapE knock‑out fragment and a pSET4s suicide vector. Additionally, the 458ΔvapE strain was transformed by a pAT18 shuttle plasmid containing the vapE gene. A functionally complemented strain for the vapE gene [termed 458ΔvapE (pvapE)] was constructed. Animal experiments demonstrated that mice infected with ZY458 and 458ΔvapE (pvapE) exhibited severe clinical symptoms, including depression, apathy, fever, anorexia, emaciation, swollen eyes and neural disorders, and died within two days of infection. All mice infected with ZY458, and 85% of mice infected with 458ΔvapE (pvapE), died within 2 days of infection. In contrast, mice inoculated with 458ΔvapE exhibited only mild clinical symptoms in the first 2 days following infection, and recovered within a week. A bacterial colonization assay demonstrated the ability of the 458ΔvapE mutant SS2 strain to colonize the heart, liver, spleen, lung and kidney of infected mice. PCR analysis of the vapE gene revealed that functional vapE was detected in virulent strains, but not in avirulent and carrier strains of S. suis SS2. These findings indicate that vapE is important for the pathogenesis of SS2.

  13. HP0197 contributes to CPS synthesis and the virulence of Streptococcus suis via CcpA.

    PubMed

    Zhang, Anding; Chen, Bo; Yuan, Zhengzhi; Li, Ran; Liu, Cheng; Zhou, Hongbo; Chen, Huanchun; Jin, Meilin

    2012-01-01

    Streptococcus suis serotype 2 (SS2), a major swine pathogen and an emerging zoonotic agent, has greatly challenged global public health. The encoding proteins with unknown functions the bacterium encodes are an obstruction to studies of the pathogenesis. A novel surface protective antigen HP0197 is one of these proteins which have no sequence homology to any known protein. In the present study, the protein was determined to be involved in bacterial virulence through an evaluation of the isogenic mutant (Δhp0197) in both mice and pigs. The experimental infection also indicated that Δhp0197 could be cleared easily during infection, which could be attributed to the reduced thickness of the capsular polysaccharides (CPS) and the significantly reduced phagocytotic resistance. Microarrays-based comparative transcriptome analysis suggested that the suppressed expression of the operon responsible for CPS synthesis might be reversed by CcpA activity, which controlled global regulation of carbon catabolite through the binding of the CcpA and HPr-Ser-46-P to the catabolite-responsive elements (cre) of the target operons. The hypothesis was approved by the fact that the purified FLAG-tagged HPr from WT stain exhibited a higher binding activity to cre with CcpA compared to the Δhp0197 by the Electrophoretic Mobility Shift Assay, suggesting lower level of phosphorylation of the phosphocarrier protein HPr at residue Ser-46 (HPr-Ser-46P) in Δhp0197. These indicated that HP0197 could enhance CcpA activity to control the expression of genes involved in carbohydrate utilization and CPS synthesis, thus contributing to the virulence of S. suis.

  14. Interaction of fibrinogen and muramidase-released protein promotes the development of Streptococcus suis meningitis

    PubMed Central

    Wang, Junping; Kong, Decong; Zhang, Shengwei; Jiang, Hua; Zheng, Yuling; Zang, Yating; Hao, Huaijie; Jiang, Yongqiang

    2015-01-01

    Muramidase-released protein (MRP) is as an important virulence marker of Streptococcus suis (S. suis) serotype 2. Our previous works have shown that MRP can bind human fibrinogen (hFg); however, the function of this interaction in S. suis meningitis is not known. In this study, we found that the deletion of mrp significantly impairs the hFg-mediated adherence and traversal ability of S. suis across human cerebral microvascular endothelial cells (hCMEC/D3). Measurement of the permeability to Lucifer yellow in vitro and Evans blue extravasation in vivo show that the MRP-hFg interaction significantly increases the permeability of the blood–brain barrier (BBB). In the mouse meningitis model, wild type S. suis caused higher bacterial loads in the brain and more severe histopathological signs of meningitis than the mrp mutant at day 3 post-infection. Western blot analysis and immunofluorescence observations reveal that the MRP-hFg interaction can destroy the cell adherens junction protein p120-catenin of hCMEC/D3. These results indicate that the MRP-hFg interaction is important in the development of S. suis meningitis. PMID:26441928

  15. Assessment of MALDI-TOF MS as Alternative Tool for Streptococcus suis Identification

    PubMed Central

    Pérez-Sancho, Marta; Vela, Ana Isabel; García-Seco, Teresa; Gottschalk, Marcelo; Domínguez, Lucas; Fernández-Garayzábal, José Francisco

    2015-01-01

    The accuracy of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identifying Streptococcus suis isolates obtained from pigs, wild animals, and humans was evaluated using a PCR-based identification assay as the gold standard. In addition, MALDI-TOF MS was compared with the commercial multi-tests Rapid ID 32 STREP system. From the 129 S. suis isolates included in the study and identified by the molecular method, only 31 isolates (24.03%) had score values ≥2.300 and 79 isolates (61.24%) gave score values between 2.299 and 2.000. After updating the currently available S. suis MALDI Biotyper database with the spectra of three additional clinical isolates of serotypes 2, 7, and 9, most isolates had statistically significant higher score values (mean score: 2.65) than those obtained using the original database (mean score: 2.182). Considering the results of the present study, we suggest using a less restrictive threshold score of ≥2.000 for reliable species identification of S. suis. According to this cut-off value, a total of 125 S. suis isolates (96.9%) were correctly identified using the updated database. These data indicate an excellent performance of MALDI-TOF MS for the identification of S. suis. PMID:26347858

  16. A Zebrafish Larval Model to Assess Virulence of Porcine Streptococcus suis Strains

    PubMed Central

    Zaccaria, Edoardo; Cao, Rui; Wells, Jerry M.; van Baarlen, Peter

    2016-01-01

    Streptococcus suis is an encapsulated Gram-positive bacterium, and the leading cause of sepsis and meningitis in young pigs resulting in considerable economic losses in the porcine industry. It is also considered an emerging zoonotic agent. In the environment, both avirulent and virulent strains occur in pigs, and virulent strains appear to cause disease in both humans and pigs. There is a need for a convenient, reliable and standardized animal model to assess S. suis virulence. A zebrafish (Danio rerio) larvae infection model has several advantages, including transparency of larvae, low cost, ease of use and exemption from ethical legislation up to 6 days post fertilization, but has not been previously established as a model for S. suis. Microinjection of different porcine strains of S. suis in zebrafish larvae resulted in highly reproducible dose- and strain-dependent larval death, strongly correlating with presence of the S. suis capsule and to the original virulence of the strain in pigs. Additionally we compared the virulence of the two-component system mutant of ciaRH, which is attenuated for virulence in both mice and pigs in vivo. Infection of larvae with the ΔciaRH strain resulted in significantly higher survival rate compared to infection with the S10 wild-type strain. Our data demonstrate that zebrafish larvae are a rapid and reliable model to assess the virulence of clinical porcine S. suis isolates. PMID:26999052

  17. Transcriptional Analysis of PRRSV-Infected Porcine Dendritic Cell Response to Streptococcus suis Infection Reveals Up-Regulation of Inflammatory-Related Genes Expression

    PubMed Central

    Auray, Gaël; Lachance, Claude; Wang, Yingchao; Gagnon, Carl A.; Segura, Mariela; Gottschalk, Marcelo

    2016-01-01

    The porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important swine pathogens and often serves as an entry door for other viral or bacterial pathogens, of which Streptococcus suis is one of the most common. Pre-infection with PRRSV leads to exacerbated disease caused by S. suis infection. Very few studies have assessed the immunological mechanisms underlying this higher susceptibility. Since antigen presenting cells play a major role in the initiation of the immune response, the in vitro transcriptional response of bone marrow-derived dendritic cells (BMDCs) and monocytes in the context of PRRSV and S. suis co-infection was investigated. BMDCs were found to be more permissive than monocytes to PRRSV infection; S. suis phagocytosis by PRRSV-infected BMDCs was found to be impaired, whereas no effect was found on bacterial intracellular survival. Transcription profile analysis, with a major focus on inflammatory genes, following S. suis infection, with and without pre-infection with PRRSV, was then performed. While PRRSV pre-infection had little effect on monocytes response to S. suis infection, a significant expression of several pro-inflammatory molecules was observed in BMDCs pre-infected with PRRSV after a subsequent infection with S. suis. While an additive effect could be observed for CCL4, CCL14, CCL20, and IL-15, a distinct synergistic up-regulatory effect was observed for IL-6, CCL5 and TNF-α after co-infection. This increased pro-inflammatory response by DCs could participate in the exacerbation of the disease observed during PRRSV and S. suis co-infection. PMID:27213692

  18. FlpS, the FNR-Like Protein of Streptococcus suis Is an Essential, Oxygen-Sensing Activator of the Arginine Deiminase System.

    PubMed

    Willenborg, Jörg; Koczula, Anna; Fulde, Marcus; de Greeff, Astrid; Beineke, Andreas; Eisenreich, Wolfgang; Huber, Claudia; Seitz, Maren; Valentin-Weigand, Peter; Goethe, Ralph

    2016-07-21

    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.

  19. Structure determination of Streptococcus suis serotype 9 capsular polysaccharide and assignment of functions of the cps locus genes involved in its biosynthesis.

    PubMed

    Vinogradov, Evgueny; Goyette-Desjardins, Guillaume; Okura, Masatoshi; Takamatsu, Daisuke; Gottschalk, Marcelo; Segura, Mariela

    2016-10-04

    Streptococcus suis serotype 9 is the most prevalent S. suis serotype in several European countries. In spite of its pathogenicity for pigs and increasing zoonotic potential, limited information is available on this serotype. Here we determined for the first time the chemical composition and structure of serotype 9 capsular polysaccharide (CPS), a major bacterial virulence factor and the antigen at the origin of S. suis classification into serotypes. Chemical and spectroscopic data gave the repeating unit sequence: [3)Glcol-6-P-3-[D-Gal(α1-2)]D-Gal(β1-3)D-Sug(β1-3)L-Rha(α1-)]n. Compared to previously characterized S. suis CPSs (serotypes 1, 1/2, 2 and 14), serotype 9 CPS does not contain sialic acid but contains a labile 4-keto sugar (2-acetamido-2,6-dideoxy-β-D-xylo-hexopyranos-4-ulose), one particular feature of this serotype. A correlation between S. suis serotype 9 CPS sequence and genes of this serotype cps locus encoding putative glycosyltransferases and polymerase responsible for the biosynthesis of the repeating unit was tentatively established. Knowledge of CPS structure and composition will contribute to better dissect the role of this bacterial component in the pathogenesis of S. suis serotype 9.

  20. Binding of Human Fibrinogen to MRP Enhances Streptococcus suis Survival in Host Blood in a αXβ2 Integrin-dependent Manner.

    PubMed

    Pian, Yaya; Li, Xueqin; Zheng, Yuling; Wu, Xiaohong; Yuan, Yuan; Jiang, Yongqiang

    2016-05-27

    The Gram-positive bacterium Streptococcus suis serotype 2 (S. suis 2), an important zoonotic pathogen, induces strong systemic infections in humans; sepsis and meningitis are the most common clinical manifestations and are often accompanied by bacteremia. However, the mechanisms of S. suis 2 survival in human blood are not well understood. In our previous study, we identified muramidase-released protein (MRP), a novel human fibrinogen (hFg)-binding protein (FBP) in S. suis 2 that is an important epidemic infection marker with an unknown mechanism in pathogenesis. The present study demonstrates that the N-terminus of MRP (a.a. 283-721) binds to both the Aα and Bβ chains of the D fragment of hFg. Strikingly, the hFg-MRP interaction improved the survival of S. suis 2 in human blood and led to the aggregation and exhaustion of polymorphonuclear neutrophils (PMNs) via an αXβ2 integrin-dependent mechanism. Other Fg-binding proteins, such as M1 (GAS) and FOG (GGS), also induced PMNs aggregation; however, the mechanisms of these FBP-hFg complexes in the evasion of PMN-mediated innate immunity remain unclear. MRP is conserved across highly virulent strains in Europe and Asia, and these data shed new light on the function of MRP in S. suis pathogenesis.

  1. FlpS, the FNR-Like Protein of Streptococcus suis Is an Essential, Oxygen-Sensing Activator of the Arginine Deiminase System

    PubMed Central

    Willenborg, Jörg; Koczula, Anna; Fulde, Marcus; de Greeff, Astrid; Beineke, Andreas; Eisenreich, Wolfgang; Huber, Claudia; Seitz, Maren; Valentin-Weigand, Peter; Goethe, Ralph

    2016-01-01

    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. PMID:27455333

  2. Streptococcus suis in employees and the environment of swine slaughterhouses in São Paulo, Brazil: Occurrence, risk factors, serotype distribution, and antimicrobial susceptibility

    PubMed Central

    Soares, Taíssa Cook Siqueira; Gottschalk, Marcelo; Lacouture, Sonia; Megid, Jane; Ribolla, Paulo Eduardo Martins; de Figueiredo Pantoja, José Carlos; Paes, Antonio Carlos

    2015-01-01

    Streptococcus suis is an important pathogen in the swine industry. This article is the first to report the occurrence, risk factors, serotype distribution, and antimicrobial susceptibility of S. suis recovered from employees and environmental samples of swine slaughterhouses in Brazil. Tonsillar swabs from all 139 pig-slaughtering employees and 261 environmental swabs were collected for detection of S. suis and serotyping by monoplex and multiplex polymerase chain reaction, respectively. Antimicrobial susceptibility was determined by the disk-diffusion method. Although S. suis was not detected in any of the tested employees, it was isolated from 25% of the environmental samples. Significant differences (P < 0.05) in the occurrence of S. suis were observed between slaughterhouses and between areas of low, medium, and high risk. The most frequent serotypes were 4 and 29, each accounting for 12% of the isolates, followed by 5, 12, 21, and 31, each accounting for 6%. High rates of susceptibility to the antimicrobials doxycycline (100%), ceftiofur (94%), ampicillin (81%), and cephalexin (75%) were observed. However, multidrug resistance was observed in all the isolates. Because S. suis is present in the environment of swine slaughterhouses, on carcasses and knives, as well as on the hands of employees in all areas, all employees are at risk of infection. PMID:26424907

  3. Binding of Human Fibrinogen to MRP Enhances Streptococcus suis Survival in Host Blood in a αXβ2 Integrin-dependent Manner

    PubMed Central

    Pian, Yaya; Li, Xueqin; Zheng, Yuling; Wu, Xiaohong; Yuan, Yuan; Jiang, Yongqiang

    2016-01-01

    The Gram-positive bacterium Streptococcus suis serotype 2 (S. suis 2), an important zoonotic pathogen, induces strong systemic infections in humans; sepsis and meningitis are the most common clinical manifestations and are often accompanied by bacteremia. However, the mechanisms of S. suis 2 survival in human blood are not well understood. In our previous study, we identified muramidase-released protein (MRP), a novel human fibrinogen (hFg)-binding protein (FBP) in S. suis 2 that is an important epidemic infection marker with an unknown mechanism in pathogenesis. The present study demonstrates that the N-terminus of MRP (a.a. 283–721) binds to both the Aα and Bβ chains of the D fragment of hFg. Strikingly, the hFg-MRP interaction improved the survival of S. suis 2 in human blood and led to the aggregation and exhaustion of polymorphonuclear neutrophils (PMNs) via an αXβ2 integrin-dependent mechanism. Other Fg-binding proteins, such as M1 (GAS) and FOG (GGS), also induced PMNs aggregation; however, the mechanisms of these FBP-hFg complexes in the evasion of PMN-mediated innate immunity remain unclear. MRP is conserved across highly virulent strains in Europe and Asia, and these data shed new light on the function of MRP in S. suis pathogenesis. PMID:27231021

  4. Streptococcus suis in employees and the environment of swine slaughterhouses in São Paulo, Brazil: Occurrence, risk factors, serotype distribution, and antimicrobial susceptibility.

    PubMed

    Soares, Taíssa Cook Siqueira; Gottschalk, Marcelo; Lacouture, Sonia; Megid, Jane; Ribolla, Paulo Eduardo Martins; Pantoja, José Carlos de Figueiredo; Paes, Antonio Carlos

    2015-10-01

    Streptococcus suis is an important pathogen in the swine industry. This article is the first to report the occurrence, risk factors, serotype distribution, and antimicrobial susceptibility of S. suis recovered from employees and environmental samples of swine slaughterhouses in Brazil. Tonsillar swabs from all 139 pig-slaughtering employees and 261 environmental swabs were collected for detection of S. suis and serotyping by monoplex and multiplex polymerase chain reaction, respectively. Antimicrobial susceptibility was determined by the disk-diffusion method. Although S. suis was not detected in any of the tested employees, it was isolated from 25% of the environmental samples. Significant differences (P < 0.05) in the occurrence of S. suis were observed between slaughterhouses and between areas of low, medium, and high risk. The most frequent serotypes were 4 and 29, each accounting for 12% of the isolates, followed by 5, 12, 21, and 31, each accounting for 6%. High rates of susceptibility to the antimicrobials doxycycline (100%), ceftiofur (94%), ampicillin (81%), and cephalexin (75%) were observed. However, multidrug resistance was observed in all the isolates. Because S. suis is present in the environment of swine slaughterhouses, on carcasses and knives, as well as on the hands of employees in all areas, all employees are at risk of infection.

  5. The Eukaryote-Like Serine/Threonine Kinase STK Regulates the Growth and Metabolism of Zoonotic Streptococcus suis

    PubMed Central

    Zhang, Chunyan; Sun, Wen; Tan, Meifang; Dong, Mengmeng; Liu, Wanquan; Gao, Ting; Li, Lu; Xu, Zhuofei; Zhou, Rui

    2017-01-01

    Like eukaryotes, bacteria express one or more serine/threonine kinases (STKs) that initiate diverse signaling networks. The STK from Streptococcus suis is encoded by a single-copy stk gene, which is crucial in stress response and virulence. To further understand the regulatory mechanism of STK in S. suis, a stk deletion strain (Δstk) and its complementary strain (CΔstk) were constructed to systematically decode STK characteristics by applying whole transcriptome RNA sequencing (RNA-Seq) and phosphoproteomic analysis. Numerous genes were differentially expressed in Δstk compared with the wild-type parental strain SC-19, including 320 up-regulated and 219 down-regulated genes. Particularly, 32 virulence-associated genes (VAGs) were significantly down-regulated in Δstk. Seven metabolic pathways relevant to bacterial central metabolism and translation are significantly repressed in Δstk. Phosphoproteomic analysis further identified 12 phosphoproteins that exhibit differential phosphorylation in Δstk. These proteins are associated with cell growth and division, glycolysis, and translation. Consistently, phenotypic assays confirmed that the Δstk strain displayed deficient growth and attenuated pathogenicity. Thus, STK is a central regulator that plays an important role in cell growth and division, as well as S. suis metabolism. PMID:28326294

  6. Complex Population Structure and Virulence Differences among Serotype 2 Streptococcus suis Strains Belonging to Sequence Type 28

    PubMed Central

    Athey, Taryn B. T.; Auger, Jean-Philippe; Teatero, Sarah; Dumesnil, Audrey; Takamatsu, Daisuke; Wasserscheid, Jessica; Dewar, Ken; Gottschalk, Marcelo; Fittipaldi, Nahuel

    2015-01-01

    Streptococcus suis is a major swine pathogen and a zoonotic agent. Serotype 2 strains are the most frequently associated with disease. However, not all serotype 2 lineages are considered virulent. Indeed, sequence type (ST) 28 serotype 2 S. suis strains have been described as a homogeneous group of low virulence. However, ST28 strains are often isolated from diseased swine in some countries, and at least four human ST28 cases have been reported. Here, we used whole-genome sequencing and animal infection models to test the hypothesis that the ST28 lineage comprises strains of different genetic backgrounds and different virulence. We used 50 S. suis ST28 strains isolated in Canada, the United States and Japan from diseased pigs, and one ST28 strain from a human case isolated in Thailand. We report a complex population structure among the 51 ST28 strains. Diversity resulted from variable gene content, recombination events and numerous genome-wide polymorphisms not attributable to recombination. Phylogenetic analysis using core genome single-nucleotide polymorphisms revealed four discrete clades with strong geographic structure, and a fifth clade formed by US, Thai and Japanese strains. When tested in experimental animal models, strains from this latter clade were significantly more virulent than a Canadian ST28 reference strain, and a closely related Canadian strain. Our results highlight the limitations of MLST for both phylogenetic analysis and virulence prediction and raise concerns about the possible emergence of ST28 strains in human clinical cases. PMID:26375680

  7. Streptococcus suis Serotype 2 Biofilms Inhibit the Formation of Neutrophil Extracellular Traps

    PubMed Central

    Ma, Fang; Yi, Li; Yu, Ningwei; Wang, Guangyu; Ma, Zhe; Lin, Huixing; Fan, Hongjie

    2017-01-01

    Invasive infections caused by Streptococcus suis serotype 2 (SS2) has emerged as a clinical problem in recent years. Neutrophil extracellular traps (NETs) are an important mechanism for the trapping and killing of pathogens that are resistant to phagocytosis. Biofilm formation can protect bacteria from being killed by phagocytes. Until now, there have only been a few studies that focused on the interactions between bacterial biofilms and NETs. SS2 in both a biofilm state and a planktonic cell state were incubated with phagocytes and NETs, and bacterial survival was assessed. DNase I and cytochalasin B were used to degrade NET DNA or suppress phagocytosis, respectively. Extracellular DNA was stained with impermeable fluorescent dye to quantify NET formation. Biofilm formation increased up to 6-fold in the presence of neutrophils, and biofilms were identified in murine tissue. Both planktonic and biofilm cells induced neutrophils chemotaxis to the infection site, with neutrophils increasing by 85.1 and 73.8%, respectively. The bacteria in biofilms were not phagocytized. The bactericidal efficacy of NETs on the biofilms and planktonic cells were equal; however, the biofilm extracellular matrix can inhibit NET release. Although biofilms inhibit NETs release, NETs appear to be an important mechanism to eliminate SS2 biofilms. This knowledge advances the understanding of biofilms and may aid in the development of treatments for persistent infections with a biofilm component. PMID:28373968

  8. Role of the capsular polysaccharide as a virulence factor for Streptococcus suis serotype 14.

    PubMed

    Roy, David; Auger, Jean-Philippe; Segura, Mariela; Fittipaldi, Nahuel; Takamatsu, Daisuke; Okura, Masatoshi; Gottschalk, Marcelo

    2015-04-01

    Streptococcus suis is an important swine pathogen and a zoonotic agent causing meningitis and septicemia. Although serotype 2 is the most virulent type, serotype 14 is emerging, and understanding of its pathogenesis is limited. To study the role of the capsular polysaccharide (CPS) of serotype 14 as a virulence factor, we constructed knockout mutants devoid of either cps14B, a highly conserved regulatory gene, or neu14C, a gene coding for uridine diphospho-N-acetylglucosamine 2-epimerase, which is involved in sialic acid synthesis. The mutants showed total loss of the CPS with coagglutination assays and electron microscopy. Phagocytosis assays showed high susceptibility of mutant Δcps14B. An in vivo murine model was used to demonstrate attenuated virulence of this non-encapsulated mutant. Despite the difference in the CPS composition of different serotypes, this study has demonstrated for the first time that the CPS of a serotype other than 2 is also an important antiphagocytic factor and a critical virulence factor.

  9. Streptococcus suis Serotype 2 Biofilms Inhibit the Formation of Neutrophil Extracellular Traps.

    PubMed

    Ma, Fang; Yi, Li; Yu, Ningwei; Wang, Guangyu; Ma, Zhe; Lin, Huixing; Fan, Hongjie

    2017-01-01

    Invasive infections caused by Streptococcus suis serotype 2 (SS2) has emerged as a clinical problem in recent years. Neutrophil extracellular traps (NETs) are an important mechanism for the trapping and killing of pathogens that are resistant to phagocytosis. Biofilm formation can protect bacteria from being killed by phagocytes. Until now, there have only been a few studies that focused on the interactions between bacterial biofilms and NETs. SS2 in both a biofilm state and a planktonic cell state were incubated with phagocytes and NETs, and bacterial survival was assessed. DNase I and cytochalasin B were used to degrade NET DNA or suppress phagocytosis, respectively. Extracellular DNA was stained with impermeable fluorescent dye to quantify NET formation. Biofilm formation increased up to 6-fold in the presence of neutrophils, and biofilms were identified in murine tissue. Both planktonic and biofilm cells induced neutrophils chemotaxis to the infection site, with neutrophils increasing by 85.1 and 73.8%, respectively. The bacteria in biofilms were not phagocytized. The bactericidal efficacy of NETs on the biofilms and planktonic cells were equal; however, the biofilm extracellular matrix can inhibit NET release. Although biofilms inhibit NETs release, NETs appear to be an important mechanism to eliminate SS2 biofilms. This knowledge advances the understanding of biofilms and may aid in the development of treatments for persistent infections with a biofilm component.

  10. Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

    PubMed Central

    Zaccaria, Edoardo; Wels, Michiel; van Baarlen, Peter; Wells, Jerry M.

    2016-01-01

    In S. suis the ComX-inducing peptide (XIP) pheromone regulates ComR-dependent transcriptional activation of comX (or sigX) the regulator of the late competence regulon. The aims of this study were to identify the ComR-regulated genes and in S. suis using genome-wide transcriptomics and identify their function based on orthology and the construction of specific knockout mutants. The ComX regulon we identified, includes all homologs of the “transformasome” a type 4-like pilus DNA binding and transport apparatus identified in Streptococcus pneumoniae, Streptococcus mutans, and Streptococcus thermophilus. A conserved CIN-box (YTACGAAYW), predicted to be bound by ComX, was found in the promoters of operons encoding genes involved in expression of the transformasome. Mutants lacking the major pilin gene comYC were not transformable demonstrating that the DNA uptake pilus is indeed required for competence development in S. suis. Competence was a transient state with the comX regulon shut down after ~15 min even when transcription of comX had not returned to basal levels, indicating other mechanisms control the exit from competence. The ComX regulon also included genes involved in DNA repair including cinA which we showed to be required for high efficiency transformation. In contrast to S. pneumoniae and S. mutans the ComX regulon of S. suis did not include endA which converts the transforming DNA into ssDNA, or ssbA, which protects the transforming ssDNA from degradation. EndA appeared to be essential in S. suis so we could not generate mutants and confirm its role in DNA transformation. Finally, we identified a putative homolog of fratricin, and a putative bacteriocin gene cluster, that were also part of the CIN-box regulon and thus may play a role in DNA release from non-competent cells, enabling gene transfer between S. suis pherotypes or S. suis and other species. S. suis mutants of oppA, the binding subunit of the general oligopeptide transporter were not

  11. Prevalence, capsular type and antimicrobial susceptibility of Streptococcus suis isolated from slaughter pigs in Korea.

    PubMed Central

    Han, D U; Choi, C; Ham, H J; Jung, J H; Cho, W S; Kim, J; Higgins, R; Chae, C

    2001-01-01

    This study was undertaken to determine the prevalence, capsular serotype, and antimicrobial susceptibility of Streptococcus suis isolated from slaughter pigs. Capsular serotype and antimicrobial susceptibility were determined by coagglutination test and agar dilution minimum inhibitory concentration, respectively. Streptococcus suis was isolated from 55 of the 406 palatine tonsillar samples tested (13.8%) and 14 of the 29 sampled herds (48.3%). Of the 55 isolates recovered from slaughter pigs, 26 (47.3%) were untypeable. Of the remaining 29 isolates, capsular serotypes 9 (9 isolates) and 16 (4 isolates) were the most common, followed by capsular serotypes 4 (3 isolates) and 7 (3 isolates). Every capsulated isolate was typeable and no palatine tonsillar sample yielded more than one serotype. Most of isolates were susceptible to low concentrations (MIC90) of amoxicillin (2 microg/mL), ceftiofur (1 microg/mL), and penicillin (1 microg/mL). No correlation was found between antimicrobial susceptibility and capsular serotype. PMID:11480519

  12. Targeting TREM-1 Signaling in the Presence of Antibiotics is Effective Against Streptococcal Toxic-Shock-Like Syndrome (STSLS) Caused by Streptococcus suis.

    PubMed

    Yang, Chao; Zhao, Jianqing; Lin, Lan; Pan, Shan; Fu, Lei; Han, Li; Jin, Meilin; Zhou, Rui; Zhang, Anding

    2015-01-01

    Streptococcus suis (S.suis), a major swine pathogen, is also a severe threat to human health. Infection with highly virulent strains of S. suis can cause human Streptococcal toxic-shock-like syndrome (STSLS), which is associated with high serum pro-inflammatory cytokine levels and a high mortality rate. Our previous study indicated that highly virulent S. suis infection could activate the TREM-1 signaling pathway, which promotes host clearance of S. suis during early infection. However, it remained to be elicited whether TREM-1 signaling could be a target against STSLS in the presence of antibiotic. In the present study, mice were infected with a highly virulent S. suis strain and then treated with rTREM-1 (the recombinant extracellular domain of TREM-1) to block TREM-1 signaling, antibiotics, both rTREM-1 and antibiotics, or PBS. The survival rates, clinical signs, serum IL-1β and TNF-α levels, and serum bacterial loads were evaluated. Treatment with rTREM-1 could aggravate the outcome of infection as described previously. Although the conventional treatment with antibiotics contributed to effective S. suis clearance, it did not improve survival significantly. In comparison, due to the reduction of the exaggerated pro-inflammatory response, treatment combined with rTREM-1 and antibiotics not only led to efficient bacterial clearance but also alleviated inflammation. In conclusion, TREM-1 signaling contributed to severe inflammatory response and benefited S. suis clearance. Therefore, blocking TREM-1 signaling could still be a target for the treatment of STSLS in the presence of antibiotics.

  13. Capsular sialic acid of Streptococcus suis serotype 2 binds to swine influenza virus and enhances bacterial interactions with virus-infected tracheal epithelial cells.

    PubMed

    Wang, Yingchao; Gagnon, Carl A; Savard, Christian; Music, Nedzad; Srednik, Mariela; Segura, Mariela; Lachance, Claude; Bellehumeur, Christian; Gottschalk, Marcelo

    2013-12-01

    Streptococcus suis serotype 2 is an important swine bacterial pathogen, and it is also an emerging zoonotic agent. It is unknown how S. suis virulent strains, which are usually found in low quantities in pig tonsils, manage to cross the first host defense lines to initiate systemic disease. Influenza virus produces a contagious infection in pigs which is frequently complicated by bacterial coinfections, leading to significant economic impacts. In this study, the effect of a preceding swine influenza H1N1 virus (swH1N1) infection of swine tracheal epithelial cells (NTPr) on the ability of S. suis serotype 2 to adhere to, invade, and activate these cells was evaluated. Cells preinfected with swH1N1 showed bacterial adhesion and invasion levels that were increased more than 100-fold compared to those of normal cells. Inhibition studies confirmed that the capsular sialic acid moiety is responsible for the binding to virus-infected cell surfaces. Also, preincubation of S. suis with swH1N1 significantly increased bacterial adhesion to/invasion of epithelial cells, suggesting that S. suis also uses swH1N1 as a vehicle to invade epithelial cells when the two infections occur simultaneously. Influenza virus infection may facilitate the transient passage of S. suis at the respiratory tract to reach the bloodstream and cause bacteremia and septicemia. S. suis may also increase the local inflammation at the respiratory tract during influenza infection, as suggested by an exacerbated expression of proinflammatory mediators in coinfected cells. These results give new insight into the complex interactions between influenza virus and S. suis in a coinfection model.

  14. Capsular Sialic Acid of Streptococcus suis Serotype 2 Binds to Swine Influenza Virus and Enhances Bacterial Interactions with Virus-Infected Tracheal Epithelial Cells

    PubMed Central

    Wang, Yingchao; Gagnon, Carl A.; Savard, Christian; Music, Nedzad; Srednik, Mariela; Segura, Mariela; Lachance, Claude; Bellehumeur, Christian

    2013-01-01

    Streptococcus suis serotype 2 is an important swine bacterial pathogen, and it is also an emerging zoonotic agent. It is unknown how S. suis virulent strains, which are usually found in low quantities in pig tonsils, manage to cross the first host defense lines to initiate systemic disease. Influenza virus produces a contagious infection in pigs which is frequently complicated by bacterial coinfections, leading to significant economic impacts. In this study, the effect of a preceding swine influenza H1N1 virus (swH1N1) infection of swine tracheal epithelial cells (NTPr) on the ability of S. suis serotype 2 to adhere to, invade, and activate these cells was evaluated. Cells preinfected with swH1N1 showed bacterial adhesion and invasion levels that were increased more than 100-fold compared to those of normal cells. Inhibition studies confirmed that the capsular sialic acid moiety is responsible for the binding to virus-infected cell surfaces. Also, preincubation of S. suis with swH1N1 significantly increased bacterial adhesion to/invasion of epithelial cells, suggesting that S. suis also uses swH1N1 as a vehicle to invade epithelial cells when the two infections occur simultaneously. Influenza virus infection may facilitate the transient passage of S. suis at the respiratory tract to reach the bloodstream and cause bacteremia and septicemia. S. suis may also increase the local inflammation at the respiratory tract during influenza infection, as suggested by an exacerbated expression of proinflammatory mediators in coinfected cells. These results give new insight into the complex interactions between influenza virus and S. suis in a coinfection model. PMID:24082069

  15. Targeting TREM-1 Signaling in the Presence of Antibiotics is Effective Against Streptococcal Toxic-Shock-Like Syndrome (STSLS) Caused by Streptococcus suis

    PubMed Central

    Yang, Chao; Zhao, Jianqing; Lin, Lan; Pan, Shan; Fu, Lei; Han, Li; Jin, Meilin; Zhou, Rui; Zhang, Anding

    2015-01-01

    Streptococcus suis (S.suis), a major swine pathogen, is also a severe threat to human health. Infection with highly virulent strains of S. suis can cause human Streptococcal toxic-shock-like syndrome (STSLS), which is associated with high serum pro-inflammatory cytokine levels and a high mortality rate. Our previous study indicated that highly virulent S. suis infection could activate the TREM-1 signaling pathway, which promotes host clearance of S. suis during early infection. However, it remained to be elicited whether TREM-1 signaling could be a target against STSLS in the presence of antibiotic. In the present study, mice were infected with a highly virulent S. suis strain and then treated with rTREM-1 (the recombinant extracellular domain of TREM-1) to block TREM-1 signaling, antibiotics, both rTREM-1 and antibiotics, or PBS. The survival rates, clinical signs, serum IL-1β and TNF-α levels, and serum bacterial loads were evaluated. Treatment with rTREM-1 could aggravate the outcome of infection as described previously. Although the conventional treatment with antibiotics contributed to effective S. suis clearance, it did not improve survival significantly. In comparison, due to the reduction of the exaggerated pro-inflammatory response, treatment combined with rTREM-1 and antibiotics not only led to efficient bacterial clearance but also alleviated inflammation. In conclusion, TREM-1 signaling contributed to severe inflammatory response and benefited S. suis clearance. Therefore, blocking TREM-1 signaling could still be a target for the treatment of STSLS in the presence of antibiotics. PMID:26618144

  16. The cps locus of Streptococcus suis serotype 16: development of a serotype-specific PCR assay.

    PubMed

    Wang, Kaicheng; Fan, Weixing; Wisselink, Henk; Lu, Chengping

    2011-12-15

    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 identified. The data suggests that the serotype 16 capsule is synthesized by a Wzy-dependent pathway. So far, no rapid and sensitive diagnostic method is available for detection of serotype 16 isolates. A serotype specific PCR test for the rapid and sensitive detection of S. suis serotype 16 was developed. Cross hybridization experiments of individual cps genes with chromosomal DNAs of 33 serotypes showed that the cps16G and cps16K genes hybridized with serotype 16 only. Primers based on cps16G were used to develop a serotype 16 specific PCR. The PCR assay was successfully used to identify S. suis serotype 16 in the 99 Chinese S. suis clinical isolates and 8 European isolates.

  17. Clonal dissemination of human isolates of Streptococcus suis serotype 14 in Thailand.

    PubMed

    Kerdsin, Anusak; Oishi, Kazunori; Sripakdee, Saowalak; Boonkerd, Nitsara; Polwichai, Pitimol; Nakamura, Shota; Uchida, Ryuichi; Sawanpanyalert, Pathom; Dejsirilert, Surang

    2009-11-01

    Most cases of Streptococcus suis infection in humans are caused by serotype 2 strains, and only a few cases caused by other serotypes have been reported. Among 177 human isolates of S. suis in Thailand, 12 (6.8 %) were identified as being of serotype 14, and an occurrence of sporadic S. suis serotype 14 infection was noted during 2006-2008, particularly in northern Thailand. Clinical presentations of the 12 patients (median age 62.9 years) included meningitis (58.3 %), septic arthritis (25 %) and sepsis (16.7 %). These clinical features were similar to those previously reported for S. suis infections, except that there were no fatal cases. All of the 12 serotype 14 strains belonged to the multilocus sequence types (ST) 105 (n=11) and the novel ST127 (n=1). Molecular typing by PFGE revealed four different pulsotypes, including an identical pattern for nine ST105 strains and three closely related patterns for two ST105 strains and one ST127 strain. Our PFGE data suggested clonal dissemination of ST105 strains in Thailand. Because serotype 14 is becoming a more common cause of S. suis infections in humans, diagnostic tests for serotype 14 should be performed in South-East Asian countries.

  18. Streptococcus anginosus ("Streptococcus milleri"): the unrecognized pathogen.

    PubMed Central

    Ruoff, K L

    1988-01-01

    "Streptococcus milleri" is an unofficial name that has been applied to a group of streptococci which, although basically similar, show various hemolytic, serological, and physiological characteristics. The species name Streptococcus anginosus has recently been recognized as the approved name for these organisms. Streptococci known as "S. milleri" have been implicated as etiologic agents in a variety of serious purulent infections, but because of their heterogeneous characteristics, these organisms may be unrecognized or misidentified by clinical laboratorians. This review describes the bacteriological aspects of organisms known as "S. milleri," their clinical significance, and the problems encountered with their identification in the clinical laboratory. PMID:3060239

  19. Fluoroquinolone Efflux in Streptococcus suis Is Mediated by SatAB and Not by SmrA ▿

    PubMed Central

    Escudero, Jose Antonio; San Millan, Alvaro; Gutierrez, Belen; Hidalgo, Laura; La Ragione, Roberto M.; AbuOun, Manal; Galimand, Marc; Ferrándiz, María José; Domínguez, Lucas; de la Campa, Adela G.; Gonzalez-Zorn, Bruno

    2011-01-01

    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 encoding these pumps were overexpressed either constitutively or in the presence of ciprofloxacin in this strain. These genes could not be cloned in plasmids in Escherichia coli despite strong expression repression. Finally, site-directed insertion of smrA and satAB in the amy locus of the Bacillus subtilis chromosome using ligated PCR amplicons allowed for the functional expression and study of both pumps. Results showed that SatAB is a narrow-spectrum fluoroquinolone exporter (norfloxacin and ciprofloxacin), susceptible to reserpine, whereas SmrA was not involved in fluoroquinolone resistance. Chromosomal integration in Bacillus is a novel method for studying efflux pumps from Gram-positive bacteria, which enabled us to demonstrate the possible role of SatAB, and not SmrA, in fluoroquinolone efflux in S. suis. PMID:21930876

  20. Metabolic Context of the Competence-Induced Checkpoint for Cell Replication in Streptococcus suis

    PubMed Central

    Zaccaria, Edoardo; Wells, Jerry M.

    2016-01-01

    Natural genetic transformation is a transient, rapidly progressing energy-consuming process characterized by expression of the transformasome and competence-associated regulatory genes. This transient state is tightly controlled to avoid potentially adverse effects of genetic recombination on genome integrity during cell division. We investigated the global response of Streptococcus suis to exposure to the SigX competence-inducing peptide (XIP), and thus to the activation of the competence machinery, using time series analysis together with PCA analysis, gene clustering followed by heatmap visualisation, and GO enrichment analysis. We explored the possible regulatory link between metabolism and competence, and predicted the physiological adaptation of S. suis during competence induction, progression and exit using transcriptome analysis. We showed that competence development is associated with a suppression of basal metabolism, which may have consequences for the microbe's resilience to fluctuations in the environment, as competence is costly in terms of use of energy and protein translation. Furthermore our data suggest that several basal metabolic pathways are incompatible with activation of competence in S. suis. This study also showed that targeting specific pathways during the development of competence, might render S. suis more vulnerable toward novel antibiotic therapies. PMID:27149631

  1. Prevalence and mechanism of resistance against macrolides and lincosamides in Streptococcus suis isolates.

    PubMed

    Martel, A; Baele, M; Devriese, L A; Goossens, H; Wisselink, H J; Decostere, A; Haesebrouck, F

    2001-11-26

    Eighty-seven Streptococcus suis isolates recovered in 1999-2000 from diseased pigs, all from different farms, were screened for resistance against macrolide and lincosamide antibiotics by the disk diffusion and agar dilution test and a PCR assay, amplifying the ermB gene and the mefA/E gene. Seventy-one percent of the isolates showed constitutive resistance to macrolide and lincosamide antibiotics (MLS(B)-phenotype). All these isolates were positive for the ermB gene in the PCR, but negative for the mefA/E gene. For all strains minimum inhibitory concentrations (MIC) against five other antimicrobial agents were determined. All strains were susceptible to penicillin. Ninety-nine percent of the isolates were susceptible to enrofloxacin and tiamulin. Eighty-five percent of the strains were resistant to doxycycline. A 540bp fragment of the ermB genes of eight S. suis strains was sequenced and compared with ermB genes of five S. pneumoniae and five S. pyogenes strains of human origin. A 100% homology was found between these fragments in seven S. suis, one S. pneumoniae and three of the S. pyogenes isolates. This study demonstrates that resistance against macrolides, lincosamides and streptogramin B is widespread in S. suis and mediated by ribosome methylation, encoded by the ermB gene.

  2. A Streptococcus suis LysM domain surface protein contributes to bacterial virulence.

    PubMed

    Wu, Zongfu; Shao, Jing; Ren, Haiyan; Tang, Huanyu; Zhou, Mingyao; Dai, Jiao; Lai, Liying; Yao, Huochun; Fan, Hongjie; Chen, Dai; Zong, Jie; Lu, Chengping

    2016-05-01

    Streptococcus suis (SS) is a major swine pathogen, as well as a zoonotic agent for humans. Numerous factors contribute to SS virulence, but the pathogenesis of SS infection is poorly understood. Here, we show that a novel SS surface protein containing a LysM at the N-terminus (SS9-LysM) contributes to SS virulence. Homology analysis revealed that the amino acid sequence of SS9-LysM from the SS strain GZ0565 shares 99.8-68.7% identity with homologous proteins from other SS strains and 41.2% identity with Group B Streptococcal protective antigen Sip. Immunization experiments showed that 7 out of 30 mice immunized with recombinant SS9-LysM were protected against challenge with the virulent GZ0565 strain, while all of the control mice died within 48h following bacterial challenge. In mouse infection model, the virulence of the SS9-LysM deletion mutant (ΔSS9-LysM) was reduced compared with the wild-type (WT) strain GZ0565 and SS9-LysM complemented strain. In addition, ΔSS9-LysM was significantly more sensitive to killing by pig blood ex vivo and mouse blood in vivo compared with the WT strain and SS9-LysM complemented strain. In vivo transcriptome analysis in mouse blood showed that the WT strain reduced the expression of host genes related to iron-binding by SS9-LysM. Moreover, the total free iron concentration in blood from infected mice was significantly lower for the ΔSS9-LysM strain compared with the WT strain. Together, our data reveal that SS9-LysM facilitates SS survival within blood by releasing more free iron from the host. This represents a new mechanism of SS pathogenesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Risk factors of Streptococcus suis infection in Vietnam. A case-control study.

    PubMed

    Nghia, Ho Dang Trung; Ho, Dang Trung Nghia; Tu, Le Thi Phuong; Le, Thi Phuong Tu; Wolbers, Marcel; Thai, Cao Quang; Cao, Quang Thai; Hoang, Nguyen Van Minh; Nguyen, Van Minh Hoang; Nga, Tran Vu Thieu; Tran, Vu Thieu Nga; Thao, Le Thi Phuong; Le, Thi Phuong Thao; Phu, Nguyen Hoan; Nguyen, Hoan Phu; Chau, Tran Thi Hong; Tran, Thi Hong Chau; Sinh, Dinh Xuan; Dinh, Xuan Sinh; Diep, To Song; To, Song Diep; Hang, Hoang Thi Thanh; Hoang, Thi Thanh Hang; Truong, Hoang; Campbell, James; Chau, Nguyen Van Vinh; Nguyen, Van Vinh Chau; Chinh, Nguyen Tran; Nguyen, Tran Chinh; Dung, Nguyen Van; Nguyen, Van Dung; Hoa, Ngo Thi; Ngo, Thi Hoa; Spratt, Brian G; Hien, Tran Tinh; Tran, Tinh Hien; Farrar, Jeremy; Schultsz, Constance

    2011-03-08

    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. A case-control study with appropriate hospital and matched community controls for each patient was conducted between May 2006 and June 2009. Potential risk factors were assessed using a standardized questionnaire and investigation of throat and rectal S. suis carriage in cases, controls and their pigs, using real-time PCR and culture of swab samples. We recruited 101 cases of S. suis meningitis, 303 hospital controls and 300 community controls. By multivariate analysis, risk factors identified for S. suis infection as compared to either control group included eating "high risk" dishes, including such dishes as undercooked pig blood and pig intestine (OR(1) = 2.22; 95%CI = [1.15-4.28] and OR(2) = 4.44; 95%CI = [2.15-9.15]), occupations related to pigs (OR(1) = 3.84; 95%CI = [1.32-11.11] and OR(2) = 5.52; 95%CI = [1.49-20.39]), and exposures to pigs or pork in the presence of skin injuries (OR(1) = 7.48; 95%CI = [1.97-28.44] and OR(2) = 15.96; 95%CI = [2.97-85.72]). S. suis specific DNA was detected in rectal and throat swabs of 6 patients and was cultured from 2 rectal samples, but was not detected in such samples of 1522 healthy individuals or patients without S. suis infection. This case control study, the largest prospective epidemiological assessment of this disease, has identified the most important risk factors associated with S. suis bacterial meningitis to be eating 'high risk' dishes popular in parts of Asia, occupational exposure to pigs and pig products, and preparation of pork in the presence of skin lesions. These risk factors can be addressed in public health campaigns aimed at preventing S. suis infection.

  4. Clonal distribution of Streptococcus suis isolated from diseased pigs in the central region of Chile

    PubMed Central

    Morales, Bárbara; Ruiz, Álvaro; Lacouture, Sonia; Gottschalk, Marcelo

    2015-01-01

    The characteristics of 29 Chilean field strains of Streptococcus suis recovered between 2007 and 2011 from pigs with clinical signs at different farms were studied. Serotyping with use of the coagglutination test revealed that all but 1 strain belonged to serotype 6; the remaining strain was serotype 22. All the serotype-6 strains were suilysin (hemolysin)-negative; in addition, they were found to be genotypically homogeneous by enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction (ERIC-PCR) and sensitive to ampicillin, ceftiofur, penicillin, and trimethoprim/sulfamethoxazole. The results indicate that, in contrast to what is generally observed in other countries, a single clone of S. suis was isolated from diseased pigs in the central region of Chile. PMID:26424917

  5. Structure, regulation, and putative function of the arginine deiminase system of Streptococcus suis.

    PubMed

    Gruening, Petra; Fulde, Marcus; Valentin-Weigand, Peter; Goethe, Ralph

    2006-01-01

    Streptococcus suis is an important cause of infectious diseases in young pigs. Little is known about the virulence factors or protective antigens of S. suis. Recently, we have identified two proteins of the arginine deiminase system (ADS) of S. suis, which were temperature induced and expressed on the streptococcal surface (N. Winterhoff, R. Goethe, P. Gruening, M. Rohde, H. Kalisz, H. E. Smith, and P. Valentin-Weigand, J. Bacteriol. 184:6768-6776, 2002). In the present study, we analyzed the complete ADS of S. suis. Due to their homologies to the recently published S. gordonii ADS genes, the genes for arginine deiminase, ornithine carbamoyl-transferase, and carbamate kinase, which were previously designated adiS, octS, and ckS, respectively, were renamed arcA, arcB, and arcC, respectively. Our data revealed that arcA, arcB, and arcC of the S. suis ADS are transcribed from an operon (arcABC operon). Additionally, putative ADS-associated genes were cloned and sequenced which, however, did not belong to the arcABC operon. These were the flpS gene upstream of the arcABC operon with homology to the flp transcription regulator of S. gordonii and the arcD, arcT, arcH, and argR genes downstream of the arcABC operon with high homologies to a putative arginine-ornithine antiporter, a putative dipeptidase of S. gordonii, a putative beta-N-acetylhexosaminidase of S. pneumoniae, and a putative arginine repressor of S. gordonii, respectively. The transcriptional start point of the arcABC operon was determined, and promoter analysis provided evidence that multiple factors contribute to the regulation of the ADS. Thus, a putative binding site for a transcription regulator of the Crp/Fnr family, an ArgR-binding site, and two cis-acting catabolite response elements were identified in the promoter-operator region of the operon. Consistent with this, we could demonstrate that the ADS of S. suis is inducible by arginine and reduced O2 tension and subject to carbon catabolite

  6. Structure, Regulation, and Putative Function of the Arginine Deiminase System of Streptococcus suis

    PubMed Central

    Gruening, Petra; Fulde, Marcus; Valentin-Weigand, Peter; Goethe, Ralph

    2006-01-01

    Streptococcus suis is an important cause of infectious diseases in young pigs. Little is known about the virulence factors or protective antigens of S. suis. Recently, we have identified two proteins of the arginine deiminase system (ADS) of S. suis, which were temperature induced and expressed on the streptococcal surface (N. Winterhoff, R. Goethe, P. Gruening, M. Rohde, H. Kalisz, H. E. Smith, and P. Valentin-Weigand, J. Bacteriol. 184:6768-6776, 2002). In the present study, we analyzed the complete ADS of S. suis. Due to their homologies to the recently published S. gordonii ADS genes, the genes for arginine deiminase, ornithine carbamoyl-transferase, and carbamate kinase, which were previously designated adiS, octS, and ckS, respectively, were renamed arcA, arcB, and arcC, respectively. Our data revealed that arcA, arcB, and arcC of the S. suis ADS are transcribed from an operon (arcABC operon). Additionally, putative ADS-associated genes were cloned and sequenced which, however, did not belong to the arcABC operon. These were the flpS gene upstream of the arcABC operon with homology to the flp transcription regulator of S. gordonii and the arcD, arcT, arcH, and argR genes downstream of the arcABC operon with high homologies to a putative arginine-ornithine antiporter, a putative dipeptidase of S. gordonii, a putative β-N-acetylhexosaminidase of S. pneumoniae, and a putative arginine repressor of S. gordonii, respectively. The transcriptional start point of the arcABC operon was determined, and promoter analysis provided evidence that multiple factors contribute to the regulation of the ADS. Thus, a putative binding site for a transcription regulator of the Crp/Fnr family, an ArgR-binding site, and two cis-acting catabolite response elements were identified in the promoter-operator region of the operon. Consistent with this, we could demonstrate that the ADS of S. suis is inducible by arginine and reduced O2 tension and subject to carbon catabolite repression

  7. Interaction of factor H-binding protein of Streptococcus suis with globotriaosylceramide promotes the development of meningitis.

    PubMed

    Kong, Decong; Chen, Zhe; Wang, Junping; Lv, Qingyu; Jiang, Hua; Zheng, Yuling; Xu, Maokai; Zhou, Xuyu; Hao, Huaijie; Jiang, Yongqiang

    2017-04-12

    Streptococcus suis is an important emerging zoonotic agent that causes acute bacterial meningitis in humans with high mortality and morbidity. Our previous work showed that factor H-binding protein (Fhb) contributed to virulence of S. suis, but the role of Fhb in the development of S. suis meningitis remained unclear. In this study, we demonstrated for the first time that Fhb contributed to the traversal of S. suis across the human blood-brain barrier by allelic-exchange mutagenesis, complementation and specific antibody blocking studies. We also showed that globotriaosylceramide (Gb3), the receptor of Fhb, was involved in this process and affected S. suis infection-induced activation of myosin light chain 2 through Rho/ROCK signaling in hCMEC/D3 cells. Using a murine model of S. suis meningitis, we further demonstrated that Gb3-deficiency prevented the mice from developing severe brain inflammation or injury. Our results demonstrate that the Fhb-Gb3 interaction plays an important role in the development of S. suis meningitis and might be a potential therapeutic target against S. suis infection.

  8. SalK/SalR, a Two-Component Signal Transduction System, Is Essential for Full Virulence of Highly Invasive Streptococcus suis Serotype 2

    PubMed Central

    Pan, Xiuzhen; Cheng, Gong; Wang, Jing; Ge, Junchao; Zheng, Feng; Cao, Min; Dong, Yaqing; Liu, Di; Wang, Jufang; Lin, Ying; Du, Hongli; Gao, George F.; Wang, Xiaoning; Hu, Fuquan; Tang, Jiaqi

    2008-01-01

    Background Streptococcus suis serotype 2 (S. suis 2, SS2) has evolved into a highly infectious entity, which caused the two recent large-scale outbreaks of human SS2 epidemic in China, and is characterized by a toxic shock-like syndrome. However, the molecular pathogenesis of this new emerging pathogen is still poorly understood. Methodology/Principal Findings 89K is a newly predicted pathogenicity island (PAI) which is specific to Chinese epidemic strains isolated from these two SS2 outbreaks. Further bioinformatics analysis revealed a unique two-component signal transduction system (TCSTS) located in the candidate 89K PAI, which is orthologous to the SalK/SalR regulatory system of Streptococcus salivarius. Knockout of salKR eliminated the lethality of SS2 in experimental infection of piglets. Functional complementation of salKR into the isogenic mutant ΔsalKR restored its soaring pathogenicity. Colonization experiments showed that the ΔsalKR mutant could not colonize any susceptible tissue of piglets when administered alone. Bactericidal assays demonstrated that resistance of the mutant to polymorphonuclear leukocyte (PMN)-mediated killing was greatly decreased. Expression microarray analysis exhibited a transcription profile alteration of 26 various genes down-regulated in the ΔsalKR mutant. Conclusions/Significance These findings suggest that SalK/SalR is requisite for the full virulence of ethnic Chinese isolates of highly pathogenic SS2, thus providing experimental evidence for the validity of this bioinformatically predicted PAI. PMID:18461172

  9. Virulence genes and genetic diversity of Streptococcus suis serotype 2 isolates from Thailand.

    PubMed

    Maneerat, K; Yongkiettrakul, S; Kramomtong, I; Tongtawe, P; Tapchaisri, P; Luangsuk, P; Chaicumpa, W; Gottschalk, M; Srimanote, P

    2013-11-01

    Isolates of Streptococcus suis from different Western countries as well as those from China and Vietnam have been previously well characterized. So far, the genetic characteristics and relationship between S. suis strains isolated from both humans and pigs in Thailand are unknown. In this study, a total of 245 S. suis isolates were collected from both human cases (epidemic and sporadic) and pigs (diseased and asymptomatic) in Thailand. Bacterial strains were identified by biochemical tests and PCR targeting both, the 16S rRNA and gdh genes. Thirty-six isolates were identified as serotype 2 based on serotyping and the cps2-PCR. These isolates were tested for the presence of six virulence-associated genes: an arginine deiminase (arcA), a 38-kDa protein and protective antigen (bay046), an extracellular factor (epf), an hyaluronidase (hyl), a muramidase-released protein (mrp) and a suilysin (sly). In addition, the genetic diversities of these isolates were studied by RAPD PCR and multilocus sequence typing (MLST) analysis. Four virulence-associated gene patterns (VAGP 1 to 4) were obtained, and the majority of isolates (32/36) carried all genes tested (VAGP1). Each of the three OPB primers used provided 4 patterns designated RAPD-A to RAPD-D. Furthermore, MLST analysis could also distinguish the 36 isolates into four sequence types (STs): ST1 (n = 32), ST104 (n = 2), ST233 (n = 1) and a newly identified ST, ST336 (n = 1). Dendrogram constructions based on RAPD patterns indicated that S. suis serotype 2 isolates from Thailand could be divided into four groups and that the characteristics of the individual groups were in complete agreement with the virulence gene profiles and STs. The majority (32/36) of isolates recovered from diseased pigs, slaughterhouse pigs or human patients could be classified into a single group (VAGP1, RAPD-A and ST1). This genetic information strongly suggests the transmission of S. suis isolates from pigs to humans in Thailand. Our findings are

  10. The Brucella suis genome reveals fundamental similarities between animal and plant pathogens and symbionts.

    PubMed

    Paulsen, Ian T; Seshadri, Rekha; Nelson, Karen E; Eisen, Jonathan A; Heidelberg, John F; Read, Timothy D; Dodson, Robert J; Umayam, Lowell; Brinkac, Lauren M; Beanan, Maureen J; Daugherty, Sean C; Deboy, Robert T; Durkin, A Scott; Kolonay, James F; Madupu, Ramana; Nelson, William C; Ayodeji, Bola; Kraul, Margaret; Shetty, Jyoti; Malek, Joel; Van Aken, Susan E; Riedmuller, Steven; Tettelin, Herve; Gill, Steven R; White, Owen; Salzberg, Steven L; Hoover, David L; Lindler, Luther E; Halling, Shirley M; Boyle, Stephen M; Fraser, Claire M

    2002-10-01

    The 3.31-Mb genome sequence of the intracellular pathogen and potential bioterrorism agent, Brucella suis, was determined. Comparison of B. suis with Brucella melitensis has defined a finite set of differences that could be responsible for the differences in virulence and host preference between these organisms, and indicates that phage have played a significant role in their divergence. Analysis of the B. suis genome reveals transport and metabolic capabilities akin to soil/plant-associated bacteria. Extensive gene synteny between B. suis chromosome 1 and the genome of the plant symbiont Mesorhizobium loti emphasizes the similarity between this animal pathogen and plant pathogens and symbionts. A limited repertoire of genes homologous to known bacterial virulence factors were identified.

  11. Vaccinator device for delivering propellant-driven aerosols of Streptococcus suis bacterin into the respiratory tracts of swine.

    PubMed

    Brown, A R; George, D W; Matteson, D K

    1997-08-01

    Metered-dose propellant-driven small particle aerosols of a killed whole bacterium, Streptococcus suis, were produced and characterized for their aerodynamic particle sizes and antigenicity as potential respiratory mucosal vaccines against S. suis infections in swine. To facilitate the efficient delivery of such vaccine aerosols to large animals, an electro-mechanical device was developed to synchronize aerosol release to an animal's inhalation cycles. The device was tested for its capacity to deliver a fluorescein conjugate of this bacterin (FITC-S. suis) into the respiratory tracts of 18 pigs. Results showed that FITC-S. suis could be detected in the lungs of swine as small as 4.5 kg with as few as two aerosol actuations. Metered-dose propellant-driven aerosols of bacterin vaccines delivered by this respiratory vaccinating device are discussed as a new approach for stimulated mucosal immunity against respiratory infections in animals.

  12. Streptococcus suis sortase A is Ca2+ independent and is inhibited by acteoside, isoquercitrin and baicalin

    PubMed Central

    Chen, Fuguang; Xie, Fang; Yang, Baoling; Wang, Chengcheng; Liu, Siguo

    2017-01-01

    Sortase A (SrtA) has long been recognized as an ideal drug target for therapeutic agents against Gram-positive pathogens. However, the SrtA of Streptococcus suis (Ss-SrtA), an important zoonotic agent, has not been studied. In this study, the enzymatic properties of Ss-SrtA were investigated, and inhibition of Ss-SrtA by natural products was evaluated. Ss-SrtA was expressed and purified. The purified recombinant Ss-SrtA had maximal activity at pH 6.0–7.5, 45°C, and showed a Km of 6.7 μM for the hydrolysis of substrate abz-LPATG-dnp. Different from Staphylococcus aureus SrtA (Sa-SrtA) which is stimulated by Ca2+, Ss-SrtA was observed to be Ca2+ independent. Structural analysis showed that salt bridges formed between K111 and D180 in Ss-SrtA replaced the function of Ca2+ in Sa-SrtA to stabilize the substrate-binding cleft. Site-directed mutagenesis identified H126, C192 and R200 as the key residues of Ss-SrtA active site. To discover potential inhibitors, the percent inhibition of sortase activity by natural products was measured. Among these selected natural products, acteoside, isoquercitrin and baicalin were discovered as novel SrtA inhibitors, with IC50 values of 36.3 ± 1.3 μM, 100.0 ± 1.3 μM and 85.4 ± 1.5 μM, respectively. The inhibitory effects of these three natural products were further confirmed on endogenous Sa-SrtA. Using a previously established S. aureus model with a fluorescent-labeled Sa-SrtA substrate, acteoside, isoquercitrin, and baicalin showed 86%, 28% and 45% inhibition on endogenous Sa-SrtA activity, respectively. Overall, these findings shed new light on enzymatic properties, Ca2+-independent catalytic mechanism and potential inhibitors of Ss-SrtA. PMID:28319184

  13. Streptococcus suis sortase A is Ca2+ independent and is inhibited by acteoside, isoquercitrin and baicalin.

    PubMed

    Chen, Fuguang; Xie, Fang; Yang, Baoling; Wang, Chengcheng; Liu, Siguo; Zhang, Yueling

    2017-01-01

    Sortase A (SrtA) has long been recognized as an ideal drug target for therapeutic agents against Gram-positive pathogens. However, the SrtA of Streptococcus suis (Ss-SrtA), an important zoonotic agent, has not been studied. In this study, the enzymatic properties of Ss-SrtA were investigated, and inhibition of Ss-SrtA by natural products was evaluated. Ss-SrtA was expressed and purified. The purified recombinant Ss-SrtA had maximal activity at pH 6.0-7.5, 45°C, and showed a Km of 6.7 μM for the hydrolysis of substrate abz-LPATG-dnp. Different from Staphylococcus aureus SrtA (Sa-SrtA) which is stimulated by Ca2+, Ss-SrtA was observed to be Ca2+ independent. Structural analysis showed that salt bridges formed between K111 and D180 in Ss-SrtA replaced the function of Ca2+ in Sa-SrtA to stabilize the substrate-binding cleft. Site-directed mutagenesis identified H126, C192 and R200 as the key residues of Ss-SrtA active site. To discover potential inhibitors, the percent inhibition of sortase activity by natural products was measured. Among these selected natural products, acteoside, isoquercitrin and baicalin were discovered as novel SrtA inhibitors, with IC50 values of 36.3 ± 1.3 μM, 100.0 ± 1.3 μM and 85.4 ± 1.5 μM, respectively. The inhibitory effects of these three natural products were further confirmed on endogenous Sa-SrtA. Using a previously established S. aureus model with a fluorescent-labeled Sa-SrtA substrate, acteoside, isoquercitrin, and baicalin showed 86%, 28% and 45% inhibition on endogenous Sa-SrtA activity, respectively. Overall, these findings shed new light on enzymatic properties, Ca2+-independent catalytic mechanism and potential inhibitors of Ss-SrtA.

  14. The novel virulence-related gene stp of Streptococcus suis serotype 9 strain contributes to a significant reduction in mouse mortality.

    PubMed

    Zhu, Haodan; Huang, Dongyan; Zhang, Wei; Wu, Zongfu; Lu, Yan; Jia, Hongying; Wang, Ming; Lu, Chengping

    2011-12-01

    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 unique to GZ0565, including stp which encodes a serine/threonine protein phosphatase known to affect the virulence and morphology of bacteria. To investigate the role of stp in pathogenesis of SS9, an isogenic stp mutant (Δstp) and a complementation strain (CΔstp) were constructed. The results demonstrated that the stp affected the expression of a few genes involving in adhesion and virulence for bacteria. The Δstp exhibited a significant decrease in HEp-2 cell adherence, compared with the wild type, and a reduced survival ratio in whole blood. The Δstp was attenuated in a CD1 murine model of infection and its LD50 values was seven-fold higher than the wild type. Our data suggest that stp is involved in the pathogenesis of SS9. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. ArgR is an essential local transcriptional regulator of the arcABC operon in Streptococcus suis and is crucial for biological fitness in an acidic environment.

    PubMed

    Fulde, Marcus; Willenborg, Joerg; de Greeff, Astrid; Benga, Laurentiu; Smith, Hilde E; Valentin-Weigand, Peter; Goethe, Ralph

    2011-02-01

    Streptococcus suis is one of the most important pathogens in pigs and can also cause severe infections in humans. Despite its clinical relevance, very little is known about the factors that contribute to its virulence. Recently, we identified a new putative virulence factor in S. suis, the arginine deiminase system (ADS), an arginine catabolic enzyme system encoded by the arcABC operon, which enables S. suis to survive in an acidic environment. In this study, we focused on ArgR, an ADS-associated regulator belonging to the ArgR/AhrC arginine repressor family. Using an argR knockout strain we were able to show that ArgR is essential for arcABC operon expression and necessary for the biological fitness of S. suis. By cDNA expression microarray analyses and quantitative real-time RT-PCR we found that the arcABC operon is the only gene cluster regulated by ArgR, which is in contrast to the situation in many other bacteria. Reporter gene analysis with gfp under the control of the arcABC promoter demonstrated that ArgR is able to activate the arcABC promoter. Electrophoretic mobility shift assays with fragments of the arcABC promoter and recombinant ArgR, and chromatin immunoprecipitation with antibodies directed against ArgR, revealed that ArgR interacts with the arcABC promoter in vitro and in vivo by binding to a region from -147 to -72 bp upstream of the transcriptional start point. Overall, our results show that in S. suis, ArgR is an essential, system-specific transcriptional regulator of the ADS that interacts directly with the arcABC promoter in vivo.

  16. Genetic diversity of Streptococcus suis isolated from three pig farms of China obtained by acquiring antibiotic resistance genes.

    PubMed

    Huang, Jinhu; Shang, Kexin; Kashif, Jam; Wang, Liping

    2015-05-01

    Acquiring antibiotic resistance genes may change an organism's genetic characteristics and the effect of antibiotics, resulting in a rapid transmission of microbial pathogens. The objectives of this experiment were to identify the features of Streptococcus suis (S. suis) isolated from three pig farms in China which are geographically isolated. Among the isolates, 56.52% were sequence type 7 (ST7), followed by ST1 (26.09%), indicating that ST7 prevails in China, as revealed by multi-locus sequence typing (MLST). Statistical analysis indicated an association between geography, sequence types and antibiotic resistance genotypes. 66.67% of the isolates in Sichuan province presented a (ermB(-) + mefA(-) + tetO(-) + tetM(-)) + ST7 type. The tetM(+) +ST7 type was the most prevalent in Jiangsu province, whereas the strains from Hebei province had a phenotype ermB(+) +tetO(+) +ST1 (63.64%). Pulsed-field gel electrophoresis (PGFE) pattern A2 with 100% similarity reflected the clonal dissemination between Sichuan and Jiangsu provinces. Strains carrying or not carrying antibiotic resistance genes presented different PFGE patterns in Hebei province. ST7 is widespread in many regions of China and a clonal dissemination occurred between Sichuan and Jiangsu provinces in diseased pigs. However, ST1 strains with macrolide and tetracycline resistance (ermB(+) +tetO(+) +ST1) isolated from a farm in Hebei province demonstrated that the genetic diversity was contributed by horizontal acquiring of ermB and tetO carrying elements. © 2014 Society of Chemical Industry.

  17. Susceptibility to antimicrobial agents of Streptococcus suis capsular type 2 strains isolated from pigs.

    PubMed

    Seol, B; Kelneric, Z; Hajsig, D; Madic, J; Naglic, T

    1996-03-01

    The minimal inhibitory concentrations (MICs) for thirty-three epidemiologicaly unrelated clinical isolates of Streptococcus suis capsular type 2 were determined in relation to ampicillin, ampicillin-sulbactam, amoxicillin, clavulanate-amoxicillin, penicillin G, cephalexin, gentamicin, streptomycin, erythromycin, tylosin and doxycycline, using the microtitre broth dilution procedure described by the U.S. National Committee for Clinical Laboratory Standards (NCCLS). Gentamicin was the most active compound tested, with an MIC for 90% of the strains tested (MIC(90)) of 0.4 mg/L. Overall, 70% of strains were resistant to doxycycline (MIC(90) > or = 100.0 mg/L), followed by penicillin G (51% of strains) (MIC(90) + or = 100.0 mg/L). Resistance to amoxicillin and ampicillin was 36.4% (MIC(90) 12.5 mg/L) and 33.3% (MIC(90) 50.0 mg/L), respectively. 15.2% of S. suis strains were resistant to streptomycin, tylosin and cephalexin with MIC90 values of 25.0 mg/L, 12.5 mg/L and 25.0 mg/L, respectively. A combination of ampicillin and sulbactam (MIC(90) 6.3 mg/L) and a combination of amoxicillin and clavulanate (MIC(90) 3.1 mg/L) as well as erythromycin (1.6 mg/L) were of the same efficacy, with a total of 9.1% resistant S. suis strains. This high percentage of resistance to doxycycline and penicillin G precludes the use of these antibiotics as empiric therapy of swine diseases.

  18. Population-Based Study of Streptococcus suis Infection in Humans in Phayao Province in Northern Thailand

    PubMed Central

    Takeuchi, Dan; Kerdsin, Anusak; Pienpringam, Anupong; Loetthong, Phacharaphan; Samerchea, Sutit; Luangsuk, Pakkinee; Khamisara, Kasean; Wongwan, Nithita; Areeratana, Prasanee; Chiranairadul, Piphat; Lertchayanti, Suwat; Petcharat, Sininat; Yowang, Amara; Chaiwongsaen, Phanupong; Nakayama, Tatsuya; Akeda, Yukihiro; Hamada, Shigeyuki; Sawanpanyalert, Pathom; Dejsirilert, Surang; Oishi, Kazunori

    2012-01-01

    Background Streptococcus suis infection in humans has received increasing worldwide recognition. Methods and Findings A prospective study of S. suis infection in humans was conducted in Phayao Province in northern Thailand to determine the incidence and the risk behaviors of the disease in this region in 2010. Thirty-one cases were confirmed. The case fatality rate was 16.1%, and the estimated incidence rate was 6.2 per 100,000 in the general population. The peak incidence occurred in May. The median age of the patients was 53 years and 64.5% were men. Consumption of raw pork products was confirmed in 22 cases and the median incubation period (range) was 2 days (0–11) after consumption of raw pork products. Isolates from 31 patients were confirmed as serotype 2 in 23 patients (74.2%) and serotype 14 in eight patients (25.8%). The major sequence types (STs) were ST1 (n = 20) for serotype 2 and ST105 (n = 8) for serotype 14. The epidemiological analysis suggested three possible clusters, which included 17 cases. In the largest possible cluster of 10 cases in Chiang Kham and its neighboring districts in May, the source of infection in four cases was identified as a raw pork dish served at the same restaurant in this district. Microbiological analysis confirmed that three of four cases associated with consumption of raw pork at this restaurant were attributable to an identical strain of serotype 2 with ST1 and pulsotype A2. Conclusions Our data suggest a high incidence rate of S. suis infection in the general population in Phayao Province in 2010 and confirm a cluster of three cases in 31 human cases. Food safety control should be strengthened especially for raw pork products in northern Thailand. PMID:22363601

  19. Genetic and virulence-phenotype characterization of serotypes 2 and 9 of Streptococcus suis swine isolates.

    PubMed

    Blume, Verena; Luque, Inmaculada; Vela, Ana I; Borge, Carmen; Maldonado, Alfonso; Domínguez, Lucas; Tarradas, Carmen; Fernández-Garayzábal, José F

    2009-09-01

    The aim of this study was to analyze the genetic characteristics and virulence phenotypes of Streptococcus suis, specifically, in clinical isolates of serotypes 2 and 9 (n = 195), obtained from diverse geographical areas across Spain. Pulsed-field gel electrophoresis (PFGE) typing identified 97 genetic profiles, 68% of which were represented by single isolates, indicative of a substantial genetic diversity among the S. suis isolates analyzed. Five PFGE profiles accounted for 33.3% of the isolates and were isolated from 38% of the herds in nine different provinces, indicative of the bacterium's widespread distribution in the Spanish swine population. Representative isolates of the most prevalent PFGE profiles of both serotypes were subjected to multilocus sequence typing (MLST) analysis. The results indicated that serotypes 2 and 9 have distinct genetic backgrounds. Serotype 2 isolates belong to the ST1 complex, a highly successful clone that has spread over most European countries. In accordance with isolates of this complex, most serotype 2 isolates also expressed the phenotype MRP(+)EF(+)SLY(+). Serotype 9 isolates belong to the ST61 complex, which is distantly related to the widespread European ST87 clone. Also, in contrast to most isolates of the European ST87 clone, which express the large variant MRP*, the majority of serotype 9 isolates (97.9%) did not express the protein.

  20. Genotypic Profile of Streptococcus suis Serotype 2 and Clinical Features of Infection in Humans, Thailand

    PubMed Central

    Kerdsin, Anusak; Dejsirilert, Surang; Puangpatra, Parichart; Sripakdee, Saowalak; Chumla, Koranan; Boonkerd, Nitsara; Polwichai, Pitimol; Tanimura, Susumu; Takeuchi, Dan; Nakayama, Tatsuya; Nakamura, Shota; Akeda, Yukihiro; Gottschalk, Marcelo; Sawanpanyalert, Pathom

    2011-01-01

    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. Infections were sporadic; case-fatality rate for adults was 9.5%, primarily in northern Thailand. Disease incidence peaked during the rainy season. Disease was classified as meningitis (58.9%) or nonmeningitis (41.1%, and included sepsis [35.4%] and others [5.7%]). Although ST1 strains were significantly associated with the meningitis category (p<0.0001), ST104 strains were significantly associated with the nonmeningitis category (p<0.0001). The ST1 and ST104 strains are capable of causing sepsis, but only the ST1 strains commonly cause meningitis. PMID:21529392

  1. Characterization of Spectinomycin Resistance in Streptococcus suis Leads to Two Novel Insights into Drug Resistance Formation and Dissemination Mechanism

    PubMed Central

    Huang, Kaisong; Zhang, Qiang; Song, Yajing; Zhang, Zhewen; Zhang, Anding; Xiao, Jingfa

    2016-01-01

    Spectinomycin is an aminocyclitol antibiotic used clinically to treat a variety of infections in animals. Here, we characterized drug resistance prevalence in clinical Streptococcus suis isolates and discovered a novel resistance mechanism in which the s5 mutation (Gly26Asp) results in high spectinomycin resistance. Additionally, a novel integrative and conjugative element encompassing a multidrug resistance spw_like-aadE-lnu(B)-lsa(E) cluster and a cadmium resistance operon were identified, suggesting a possible cause for the wide dissemination of spectinomycin resistance in S. suis. PMID:27458226

  2. Analysis of Genetic Diversity of Streptococcus suis Clinical Isolates from Pigs in Spain by Pulsed-Field Gel Electrophoresis

    PubMed Central

    Vela, Ana I.; Goyache, Joaquin; Tarradas, Carmen; Luque, Inmaculada; Mateos, Ana; Moreno, Miguel A.; Borge, Carmen; Perea, J. Anselmo; Domínguez, Lucas; Fernández-Garayzábal, José F.

    2003-01-01

    Pulsed-field gel electrophoresis (PFGE) was used to investigate the diversity of Streptococcus suis isolates of various serotypes recovered from swine clinical samples in Spain. Capsular types 9 (64.9%) and 2 (14.8%) were the most frequently isolated serotypes followed by serotype 7 (5.9%) and serotype 8 (4.3%). The PFGE results of this study with 60 different pulsotypes indicate a great genetic diversity among the S. suis isolates, which is consistent with the broad distribution of S. suis in the swine population. Forty-five percent of the pulsotypes corresponded to single isolates, no pulsotype was common to all farms, and at least 3 different pulsotypes were isolated in 56% of herds in which more than 3 clinical isolates were analyzed. These results reveal a great diversity both between and within herds throughout the strains of S. suis studied, demonstrating that different strains of S. suis are associated with infection in pigs. Some pulsotypes were more frequently isolated and exhibited a wider distribution over herds than others, and were the unique or predominant strains in several herds, suggesting the existence of a prevalent or a few prevalent clones responsible for a large proportion of clinical cases. Overall, the great genetic heterogeneity of the clinical strains of S. suis, the isolation of different strains within the same herd, and the predominance of particular strains in some herds are evidence that infection by S. suis is a dynamic process and reinforce the idea that the epidemiology of S. suis infection is very complex. PMID:12791872

  3. Identification of major Streptococcus suis serotypes 2, 7, 8 and 9 isolated from pigs and humans in upper northeastern Thailand.

    PubMed

    Nutravong, Thitima; Angkititrakul, Sunpetch; Jiwakanon, Netchanok; Wongchanthong, Wanlaya; Dejsirilerts, Surang; Nawa, Yukifumi

    2014-09-01

    Streptococcus suis serotype 2 infections occur in many provinces of north-eastern Thailand, knowledge concerning the prevalence of the common S. suis serotypes (1, 1/2, 2, 5, 7, 8, 9, 14 and 16) among healthy and diseased pigs in upper northeastern Thailand remains limited. This study investigated S. suis isolates from pigs (healthy and diseased) and also from humans using 11 conventional biochemical tests, 16S rDNA PCR and sequence analysis and multiplex PCR genotyping of porcine cps and gdh. Thirty-three isolates were obtained between 2009 and 2012 from blood or cerebrospinal fluid of patients from northeastern Thailand previously diagnosed with S. suis infection, based on clinical symptoms and laboratory diagnosis using 11 biochemical tests and PCR detection of 16S rDNA and cps. Eleven S. suis isolates were obtained between 2006 and 2009 from diseased pigs with clinical signs and laboratory diagnoses. In addition, 43 isolates obtained from 741 nasal swab cultures of slaughtered pigs between 2011 and 2012 were included. All three methods showed similar sensitivity in detection of S. suis from clinical and diseased pig specimens, although in healthy pigs, the 11 conventional biochemical methods yielded 2.3% false positives, and the gdh PCR detection method exhibited 31% false negatives. S. suis was present among healthy pigs in 8 of 10 provinces in upper northeastern Thailand, giving an average prevalence of 5.7% (range 1%-17%) using conventional methods together with 16S rDNA PCR assay. False positives by conventional methods were due to species with similar phenotypes, such as viridian streptococci, and are not statistically different from those obtained with the 16S rDNA PCR method, and the false negatives using gdh PCR assay will require further investigation. As S. suis was recovered from both diseased and healthy pigs, raw or undercooked pork products should be considered unsafe for handling or consumption in these regions of Thailand.

  4. Analysis of genetic diversity of Streptococcus suis clinical isolates from pigs in Spain by pulsed-field gel electrophoresis.

    PubMed

    Vela, Ana I; Goyache, Joaquin; Tarradas, Carmen; Luque, Inmaculada; Mateos, Ana; Moreno, Miguel A; Borge, Carmen; Perea, J Anselmo; Domínguez, Lucas; Fernández-Garayzábal, José F

    2003-06-01

    Pulsed-field gel electrophoresis (PFGE) was used to investigate the diversity of Streptococcus suis isolates of various serotypes recovered from swine clinical samples in Spain. Capsular types 9 (64.9%) and 2 (14.8%) were the most frequently isolated serotypes followed by serotype 7 (5.9%) and serotype 8 (4.3%). The PFGE results of this study with 60 different pulsotypes indicate a great genetic diversity among the S. suis isolates, which is consistent with the broad distribution of S. suis in the swine population. Forty-five percent of the pulsotypes corresponded to single isolates, no pulsotype was common to all farms, and at least 3 different pulsotypes were isolated in 56% of herds in which more than 3 clinical isolates were analyzed. These results reveal a great diversity both between and within herds throughout the strains of S. suis studied, demonstrating that different strains of S. suis are associated with infection in pigs. Some pulsotypes were more frequently isolated and exhibited a wider distribution over herds than others, and were the unique or predominant strains in several herds, suggesting the existence of a prevalent or a few prevalent clones responsible for a large proportion of clinical cases. Overall, the great genetic heterogeneity of the clinical strains of S. suis, the isolation of different strains within the same herd, and the predominance of particular strains in some herds are evidence that infection by S. suis is a dynamic process and reinforce the idea that the epidemiology of S. suis infection is very complex.

  5. GidA, a tRNA Modification Enzyme, Contributes to the Growth, and Virulence of Streptococcus suis Serotype 2

    PubMed Central

    Gao, Ting; Tan, Meifang; Liu, Wanquan; Zhang, Chunyan; Zhang, Tengfei; Zheng, Linlin; Zhu, Jiawen; Li, Lu; Zhou, Rui

    2016-01-01

    Glucose-inhibited division protein (GidA), is a tRNA modification enzyme functioning together with MnmE in the addition of a carboxymethylaminomethyl group to position 5 of the anticodon wobble uridine of tRNA. Here, we report a GidA homolog from a Chinese isolate SC-19 of the zoonotic Streptococcus suis serotype 2 (SS2). gidA disruption led to a defective growth, increased capsule thickness, and reduced hemolytic activity. Moreover, the gidA deletion mutant (ΔgidA) displayed reduced mortality and bacterial loads in mice, reduced ability of adhesion to and invasion in epithelial cells, and increased sensitivity to phagocytosis. The iTRAQ analysis identified 372 differentially expressed (182 up- and 190 down-regulated) proteins in ΔgidA and SC-19. Numerous DNA replication, cell division, and virulence associated proteins were downregulated, whereas many capsule synthesis enzymes were upregulated by gidA disruption. This is consistent with the phenotypes of the mutant. Thus, GidA is a translational regulator that plays an important role in the growth, cell division, capsule biosynthesis, and virulence of SS2. Our findings provide new insight into the regulatory function of GidA in bacterial pathogens. PMID:27148493

  6. GidA, a tRNA Modification Enzyme, Contributes to the Growth, and Virulence of Streptococcus suis Serotype 2.

    PubMed

    Gao, Ting; Tan, Meifang; Liu, Wanquan; Zhang, Chunyan; Zhang, Tengfei; Zheng, Linlin; Zhu, Jiawen; Li, Lu; Zhou, Rui

    2016-01-01

    Glucose-inhibited division protein (GidA), is a tRNA modification enzyme functioning together with MnmE in the addition of a carboxymethylaminomethyl group to position 5 of the anticodon wobble uridine of tRNA. Here, we report a GidA homolog from a Chinese isolate SC-19 of the zoonotic Streptococcus suis serotype 2 (SS2). gidA disruption led to a defective growth, increased capsule thickness, and reduced hemolytic activity. Moreover, the gidA deletion mutant (ΔgidA) displayed reduced mortality and bacterial loads in mice, reduced ability of adhesion to and invasion in epithelial cells, and increased sensitivity to phagocytosis. The iTRAQ analysis identified 372 differentially expressed (182 up- and 190 down-regulated) proteins in ΔgidA and SC-19. Numerous DNA replication, cell division, and virulence associated proteins were downregulated, whereas many capsule synthesis enzymes were upregulated by gidA disruption. This is consistent with the phenotypes of the mutant. Thus, GidA is a translational regulator that plays an important role in the growth, cell division, capsule biosynthesis, and virulence of SS2. Our findings provide new insight into the regulatory function of GidA in bacterial pathogens.

  7. Postantibiotic effects and postantibiotic sub-MIC effects of tilmicosin, erythromycin and tiamulin on erythromycin-resistant Streptococcus suis.

    PubMed

    Wang, Liping; Zhang, Yuanshu

    2009-10-01

    The postantibiotic effects (PAEs) and postantibiotic sub-MIC effects (PA SMEs) of tilmicosin, erythromycin and tiamulin on erythromycin-susceptible and erythromycin-resistant strains of Streptococcus suis (M phenotype) were investigated in vitro. Tilmicosin and tiamulin induced significantly longer PAE and PA SME against both erythromycin-susceptible and erythromycin-resistant strains than did erythromycin. The durations of PAE and PA SMEs were proportional to the concentrations of drugs used for exposure. The PA SMEs were substantially longer than PAEs on S. suis (P<0.05) regardless of the antimicrobial used for exposure. The results indicated that the PAE and PA SME could help in the design of efficient control strategies for infection especially caused by erythromycin-resistant S. suis and that they may provide additional valuable information for the rational drug use in clinical practice.

  8. Comparative proteomic analysis of Streptococcus suis biofilms and planktonic cells that identified biofilm infection-related immunogenic proteins.

    PubMed

    Wang, Yang; Yi, Li; Wu, Zongfu; Shao, Jing; Liu, Guangjin; Fan, Hongjie; Zhang, Wei; Lu, Chengping

    2012-01-01

    Streptococcus suis (SS) is a zoonotic pathogen that causes severe disease symptoms in pigs and humans. Biofilms of SS bind to extracellular matrix proteins in both endothelial and epithelial cells and cause persistent infections. In this study, the differences in the protein expression profiles of SS grown either as planktonic cells or biofilms were identified using comparative proteomic analysis. The results revealed the existence of 13 proteins of varying amounts, among which six were upregulated and seven were downregulated in the Streptococcus biofilm compared with the planktonic controls. The convalescent serum from mini-pig, challenged with SS, was applied in a Western blot assay to visualize all proteins from the biofilm that were grown in vitro and separated by two-dimensional gel electrophoresis. A total of 10 immunoreactive protein spots corresponding to nine unique proteins were identified by MALDI-TOF/TOF-MS. Of these nine proteins, five (Manganese-dependent superoxide dismutase, UDP-N-acetylglucosamine 1-carboxyvinyltransferase, ornithine carbamoyltransferase, phosphoglycerate kinase, Hypothetical protein SSU05_0403) had no previously reported immunogenic properties in SS to our knowledge. The remaining four immunogenic proteins (glyceraldehyde-3-phosphate dehydrogenase, hemolysin, pyruvate dehydrogenase and DnaK) were identified under both planktonic and biofilm growth conditions. In conclusion, the protein expression pattern of SS, grown as biofilm, was different from the SS grown as planktonic cells. These five immunogenic proteins that were specific to SS biofilm cells may potentially be targeted as vaccine candidates to protect against SS biofilm infections. The four proteins common to both biofilm and planktonic cells can be targeted as vaccine candidates to protect against both biofilm and acute infections.

  9. Genetic Diversity of Streptococcus suis Strains Isolated from Pigs and Humans as Revealed by Pulsed-Field Gel Electrophoresis

    PubMed Central

    Berthelot-Hérault, Florence; Marois, Corinne; Gottschalk, Marcelo; Kobisch, Marylène

    2002-01-01

    The genetic diversity of 123 Streptococcus suis strains of capsular types 2, 1/2, 3, 7, and 9, isolated from pigs in France and from humans in different countries, was evaluated by pulsed-field gel electrophoresis (PFGE) of DNA restricted with SmaI. The method was highly discriminative (D = 0.98), results were reproducible, and the PFGE analysis was easy to interpret. Among all S. suis strains, 74 PFGE patterns were shown. At 60% homology, three groups (A, B, and C) were identified, and at 69% homology, eight subgroups (a to h) were observed. Strains isolated from diseased pigs or from humans were statistically clustered in group B, especially in subgroup d. By contrast, S. suis strains isolated from clinically healthy pigs were preferentially included in subgroup b of group A. Relationships could be established between capsular types 1/2, 3, and 9 and groups A, e, and B, respectively. S. suis strains isolated from humans were homogeneous, and a very high level of association between these strains and four DNA patterns was observed. The PFGE used in this study is a very useful tool for evaluating the genetic diversity of S. suis strains, and it would be used for epidemiological investigations. PMID:11825980

  10. Genetic diversity of Streptococcus suis strains isolated from pigs and humans as revealed by pulsed-field gel electrophoresis.

    PubMed

    Berthelot-Hérault, Florence; Marois, Corinne; Gottschalk, Marcelo; Kobisch, Marylène

    2002-02-01

    The genetic diversity of 123 Streptococcus suis strains of capsular types 2, 1/2, 3, 7, and 9, isolated from pigs in France and from humans in different countries, was evaluated by pulsed-field gel electrophoresis (PFGE) of DNA restricted with SmaI. The method was highly discriminative (D = 0.98), results were reproducible, and the PFGE analysis was easy to interpret. Among all S. suis strains, 74 PFGE patterns were shown. At 60% homology, three groups (A, B, and C) were identified, and at 69% homology, eight subgroups (a to h) were observed. Strains isolated from diseased pigs or from humans were statistically clustered in group B, especially in subgroup d. By contrast, S. suis strains isolated from clinically healthy pigs were preferentially included in subgroup b of group A. Relationships could be established between capsular types 1/2, 3, and 9 and groups A, e, and B, respectively. S. suis strains isolated from humans were homogeneous, and a very high level of association between these strains and four DNA patterns was observed. The PFGE used in this study is a very useful tool for evaluating the genetic diversity of S. suis strains, and it would be used for epidemiological investigations.

  11. Antimicrobial susceptibility of Streptococcus suis isolated from swine in France and from humans in different countries between 1996 and 2000.

    PubMed

    Marie, J; Morvan, H; Berthelot-Hérault, F; Sanders, P; Kempf, I; Gautier-Bouchardon, A V; Jouy, E; Kobisch, M

    2002-08-01

    The susceptibility of 135 Streptococcus suis strains isolated from pigs (n = 110) and from humans (n = 25) to 13 antimicrobial agents was studied by microdilution and disc diffusion methods using Mueller-Hinton Agar II (MH) supplemented with either defibrinated sheep blood (MHSB) or horse serum (MHHS). Results were similar for both methods used except for penicillin G whose zone diameters were reduced with MHSB compared with MHHS. When MH was supplemented with sheep blood, 39% of S. suis strains classified as penicillin susceptible by MHHS microdilution showed intermediate susceptibility. Nearly all strains were susceptible to penicillin G (except by disc diffusion in MHSB), amoxicillin, ceftiofur, florfenicol, gentamicin and bacitracin. The least active antimicrobial agents were doxycycline and macrolides/lincosamides. High-level resistance (MIC > 500 mg/L or zone diameters < 10 mm) to streptomycin and kanamycin was detected in only a few strains. The virulence of strains did not seem to be related to antimicrobial resistance because no statistical difference was reported between the proportion of resistant strains of S. suis isolated from pigs with meningitis, septicaemia and arthritis, and those from tonsils and nasal cavities. However, significant differences were found in the proportions of macrolide- or doxycycline-resistant strains between S. suis serotype 2 and other serotypes. The results of antibiotic susceptibility testing presented in this study indicate that beta-lactams can be used in empirical treatment of human and pig S. suis infections in France.

  12. Avian influenza virus, Streptococcus suis serotype 2, severe acute respiratory syndrome-coronavirus and beyond: molecular epidemiology, ecology and the situation in China

    PubMed Central

    Ma, Ying; Feng, Youjun; Liu, Di; Gao, George F.

    2009-01-01

    The outbreak and spread of severe acute respiratory syndrome-associated coronavirus and the subsequent identification of its animal origin study have heightened the world's awareness of animal-borne or zoonotic pathogens. In addition to SARS, the highly pathogenic avian influenza virus (AIV), H5N1, and the lower pathogenicity H9N2 AIV have expanded their host ranges to infect human beings and other mammalian species as well as birds. Even the ‘well-known’ reservoir animals for influenza virus, migratory birds, became victims of the highly pathogenic H5N1 virus. Not only the viruses, but bacteria can also expand their host range: a new disease, streptococcal toxic shock syndrome, caused by human Streptococcus suis serotype 2 infection, has been observed in China with 52 human fatalities in two separate outbreaks (1998 and 2005, respectively). Additionally, enterohaemorrhagic Escherichia coli O157:H7 infection has increased worldwide with severe disease. Several outbreaks and sporadic isolations of this pathogen in China have made it an important target for disease control. A new highly pathogenic variant of porcine reproductive and respiratory syndrome virus (PRRSV) has been isolated in both China and Vietnam recently; although PRRSV is not a zoonotic human pathogen, its severe outbreaks have implications for food safety. All of these pathogens occur in Southeast Asia, including China, with severe consequences; therefore, we discuss the issues in this article by addressing the situation of the zoonotic threat in China. PMID:19687041

  13. Lysogenic Streptococcus suis Isolate SS2-4 Containing Prophage SMP Showed Increased Mortality in Zebra Fish Compared to the Wild-Type Isolate

    PubMed Central

    Tang, Fang; Zhang, Wei; Lu, Chengping

    2013-01-01

    Streptococcus suis (S. suis) infection is considered to be a major problem in the swine industry worldwide. Based on the capsular type, 33 serotypes of S. suis have been described, with serotype 2 (SS2) being the most frequently isolated from diseased piglets. Little is known, however, about the pathogenesis and virulence factors of S. suis. Research on bacteriophages highlights a new area in S. suis research. A S. suis serotype 2 bacteriophage, designated SMP, has been previously isolated in our laboratory. Here, we selected a lysogenic isolate in which the SMP phage was integrated into the chromosome of strain SS2-4. Compared to the wild-type isolate, the lysogenic strain showed increased mortality in zebra fish. Moreover the sensitivity of the lysogenic strain to lysozyme was seven times higher than that of the wild-type. PMID:23326601

  14. 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.

    PubMed

    Willenborg, Jörg; de Greeff, Astrid; Jarek, Michael; Valentin-Weigand, Peter; Goethe, Ralph

    2014-04-01

    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. © 2014 John Wiley & Sons Ltd.

  15. Potentially hazardous Streptococcus suis strains latent in asymptomatic pigs in a major swine production area of Thailand.

    PubMed

    Meekhanon, Nattakan; Kaewmongkol, Sarawan; Phimpraphai, Waraphon; Okura, Masatoshi; Osaki, Makoto; Sekizaki, Tsutomu; Takamatsu, Daisuke

    2017-05-01

    Carrier pigs have been considered as the major reservoir of Streptococcus suis and couldbe a significant source of human infection. Therefore, we investigated the prevalence and characteristics of latent S. suis in asymptomatic pigs in the pig-farming area of central Thailand, and compared the data to those previously reported in other regions. We collected samples from 340 asymptomatic pigs. S. suis isolates from the samples were confirmed by species-specific PCR (recN PCR). The capsular polysaccharide synthesis gene (cps) types, virulence-associated gene profiles and sequence types (STs) of the isolates were investigated.Results/Key findings. The prevalence of S. suis found in this study was 37 % (125/340 pigs). The most prevalent genotype was mrp-/epf-/sly-. Among the 16 cps-types identified in 135 isolates, cps-type 16 was the most frequent (11 %), whereas 44 % of the isolates were non-typable. In common with the strains causing human sepsis in Thailand, two cps-type 9 isolates and a cps-type 24 isolate from slaughtered pigs belonged to ST16 and ST221, respectively. All the isolated cps-type 2 strains were confirmed as serotype 2 by co-agglutination tests, and these belonged to ST104, the unique ST commonly found in Thai patients; however, in contrast to the endemic areas, the prevalence of serotype 2 strains was relatively low (2 %) and no ST1 isolate was found. Our results showed the population structure differences between S. suis in central Thailand and other regions; however, zoonotic S. suis is certainly latent in asymptomatic pigs in this intensive swine production area.

  16. Development of loop-mediated isothermal amplification to detect Streptococcus suis and its application to retail pork meat in Japan.

    PubMed

    Arai, Sakura; Tohya, Mari; Yamada, Ryoko; Osawa, Ro; Nomoto, Ryohei; Kawamura, Yoshiaki; Sekizaki, Tsutomu

    2015-09-02

    We here developed a novel loop-mediated isothermal amplification (LAMP) method to detect Streptococcus suis in raw pork meat. This method, designated LAMPSS, targeted the recombination/repair protein (recN) gene of S. suis and detected all serotypes of S. suis, except those taxonomically removed from authentic S. suis, i.e., serotypes 20, 22, 26, 32, 33, and 34. The specificity of LAMPSS was confirmed and its detection limit was 5.4cfu/reaction. Among the 966 raw pork meat samples examined, including sliced pork, minced pork, and the liver, tongue, heart, and small intestine, 255 samples tested positive with LAMPSS. The rate of contamination was higher in the organs than in pork. No significant difference was observed in the total bacterial count between LAMPSS-positive and -negative samples. The number of shops that provided LAMPSS-positive pork was slightly higher in those that sold swine organs and pork than in those that sold only pork, suggesting that cross contamination occurred from the organs to pork. Among the 255 which tested positive for LAMPSS, only 47 samples tested positive for the previously described LAMP specific for S. suis serotype 2. Two isolates of S. suis serotype 2, belonging to sequence type 28, which is potentially hazardous to humans, as well as those of some other serotypes were obtained from 19 out of 47 samples by combining LAMP with a replica plating method. These results suggest that LAMPSS will be a useful tool for the surveillance of raw pork meat in the retail market. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Characterization and determination of holin protein of Streptococcus suis bacteriophage SMP in heterologous host

    PubMed Central

    2012-01-01

    Background Holins are a group of phage-encoded membrane proteins that control access of phage-encoded endolysins to the peptidoglycan, and thereby trigger the lysis process at a precise time point as the 'lysis clock'. SMP is an isolated and characterized Streptococcus suis lytic phage. The aims of this study were to determine the holin gene, HolSMP, in the genome of SMP, and characterized the function of holin, HolSMP, in phage infection. Results HolSMP was predicted to encode a small membrane protein with three hydrophobic transmembrane helices. During SMP infections, HolSMP was transcribed as a late gene and HolSMP accumulated harmlessly in the cell membrane before host cell lysis. Expression of HolSMP in Escherichia coli induced an increase in cytoplasmic membrane permeability, an inhibition of host cell growth and significant cell lysis in the presence of LySMP, the endolysin of phage SMP. HolSMP was prematurely triggered by the addition of energy poison to the medium. HolSMP complemented the defective λ S allele in a non-suppressing Escherichia coli strain to produce phage plaques. Conclusions Our results suggest that HolSMP is the holin protein of phage SMP and a two-step lysis system exists in SMP. PMID:22436471

  18. Streptococcus suis Type 2 SSU0587 Protein is a Beta-Galactosidase That Contributes to Bacterial Adhesion but Not to Virulence in Mice

    PubMed Central

    TANG, Yulong; ZHANG, Xiaoyan; YIN, Yulong; HARDWIDGE, Philip R.; FANG, Weihuan

    2014-01-01

    ABSTRACT Bacterial surface proteins play key roles in virulence and often contribute to bacterial adhesion and invasion. We discovered that the Streptococcus suis type 2 (SS2) gene SSU0587 encodes a protein of 1,491 amino acids that possesses β-galactosidase activity. The surface association of the protein was dependent upon sortase activity. Deleting SSU0587 from clinical SS2 isolate JX081101 caused a loss of both β-galactosidase activity and adherence to microvascular endothelial cells. Deleting SSU0587 had no measurable impact on either invasion of microvascular endothelial cells or on virulence in a murine infection model, although the concentration of JX081101ΔSSU0587 was reduced in the brains of infected mice, as compared with the pathogen loads of the wild-type strain. PMID:24670993

  19. Streptococcus suis type 2 SSU0587 protein is a beta-galactosidase that contributes to bacterial adhesion but not to virulence in mice.

    PubMed

    Tang, Yulong; Zhang, Xiaoyan; Yin, Yulong; Hardwidge, Philip R; Fang, Weihuan

    2014-07-01

    Bacterial surface proteins play key roles in virulence and often contribute to bacterial adhesion and invasion. We discovered that the Streptococcus suis type 2 (SS2) gene SSU0587 encodes a protein of 1,491 amino acids that possesses β-galactosidase activity. The surface association of the protein was dependent upon sortase activity. Deleting SSU0587 from clinical SS2 isolate JX081101 caused a loss of both β-galactosidase activity and adherence to microvascular endothelial cells. Deleting SSU0587 had no measurable impact on either invasion of microvascular endothelial cells or on virulence in a murine infection model, although the concentration of JX081101ΔSSU0587 was reduced in the brains of infected mice, as compared with the pathogen loads of the wild-type strain.

  20. Distribution of Suicin Gene Clusters in Streptococcus suis Serotype 2 Belonging to Sequence Types 25 and 28

    PubMed Central

    Athey, Taryn B. T.; Vaillancourt, Katy; Frenette, Michel; Gottschalk, Marcelo

    2016-01-01

    Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by Streptococcus suis. In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 S. suis strains belonging to sequence type (ST) 25 and ST28, the two dominant STs identified in North America. The genomes of 102 strains were interrogated for the presence of suicin gene clusters encoding suicins 90-1330, 3908, and 65. The gene cluster encoding suicin 65 was the most prevalent and mainly found among ST25 strains. In contrast, none of the genes related to suicin 90-1330 production were identified in 51 ST25 strains nor in 35/51 ST28 strains. However, the complete suicin 90-1330 gene cluster was found in ten ST28 strains, although some genes in the cluster were truncated in three of these isolates. The vast majority (101/102) of S. suis strains did not possess any of the genes encoding suicin 3908. In conclusion, this study indicates heterogeneous distribution of suicin genes in S. suis. PMID:28078298

  1. Correlation between PFGE Groups and mrp/epf/sly Genotypes of Human Streptococcus suis Serotype 2 in Northern Thailand.

    PubMed

    Tharavichitkul, Prasit; Wongsawan, Kanreuthai; Takenami, Naoki; Pruksakorn, Sumalee; Fongcom, Achara; Gottschalk, Marcelo; Khanthawa, Banyong; Supajatura, Volaluk; Takai, Shinji

    2014-01-01

    Streptococcus suis infection is a severe zoonotic disease commonly found in Northern Thailand where people often consume raw pork and/or pig's blood. The most frequent clinical presentations are meningitis, sepsis, and endocarditis with higher rate of mortality and hearing loss sequelae. To clarify the correlation between pulsed-field gel electrophoresis (PFGE) groups and mrp/epf/sly genotypes of S. suis serotype 2, 62 patient and 4 healthy pig isolates from Northern Thailand were studied. By PFGE analysis, at 66% homology, most human isolates (69.4%) and 1 pig isolate were in group A, whereas 14.5% of human isolates and 3 out of 4 pig isolates were in group D. According to mrp/epf/sly genotypes, 80.6% of human isolates were identified in mrp (+) epf (-) sly (-) and only 12.9% were in mrp (-) epf (-) sly (+) genotypes; in contrast, 1 and 3 pig isolates were detected in these two genotypes, respectively. Interestingly, all isolates of S. suis serotype 2 classified in PFGE groups A, B, and E were set in mrp (+) epf (-) sly (-) genotypes. These data show a close correlation between PFGE groups and mrp/epf/sly genotypes of human S. suis serotype 2.

  2. Correlation between PFGE Groups and mrp/epf/sly Genotypes of Human Streptococcus suis Serotype 2 in Northern Thailand

    PubMed Central

    Tharavichitkul, Prasit; Wongsawan, Kanreuthai; Takenami, Naoki; Pruksakorn, Sumalee; Fongcom, Achara; Gottschalk, Marcelo; Khanthawa, Banyong; Supajatura, Volaluk; Takai, Shinji

    2014-01-01

    Streptococcus suis infection is a severe zoonotic disease commonly found in Northern Thailand where people often consume raw pork and/or pig's blood. The most frequent clinical presentations are meningitis, sepsis, and endocarditis with higher rate of mortality and hearing loss sequelae. To clarify the correlation between pulsed-field gel electrophoresis (PFGE) groups and mrp/epf/sly genotypes of S. suis serotype 2, 62 patient and 4 healthy pig isolates from Northern Thailand were studied. By PFGE analysis, at 66% homology, most human isolates (69.4%) and 1 pig isolate were in group A, whereas 14.5% of human isolates and 3 out of 4 pig isolates were in group D. According to mrp/epf/sly genotypes, 80.6% of human isolates were identified in mrp+epf−sly− and only 12.9% were in mrp−epf−sly+ genotypes; in contrast, 1 and 3 pig isolates were detected in these two genotypes, respectively. Interestingly, all isolates of S. suis serotype 2 classified in PFGE groups A, B, and E were set in mrp+epf−sly− genotypes. These data show a close correlation between PFGE groups and mrp/epf/sly genotypes of human S. suis serotype 2. PMID:24734186

  3. Distribution of Suicin Gene Clusters in Streptococcus suis Serotype 2 Belonging to Sequence Types 25 and 28.

    PubMed

    Athey, Taryn B T; Vaillancourt, Katy; Frenette, Michel; Fittipaldi, Nahuel; Gottschalk, Marcelo; Grenier, Daniel

    2016-01-01

    Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by Streptococcus suis. In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 S. suis strains belonging to sequence type (ST) 25 and ST28, the two dominant STs identified in North America. The genomes of 102 strains were interrogated for the presence of suicin gene clusters encoding suicins 90-1330, 3908, and 65. The gene cluster encoding suicin 65 was the most prevalent and mainly found among ST25 strains. In contrast, none of the genes related to suicin 90-1330 production were identified in 51 ST25 strains nor in 35/51 ST28 strains. However, the complete suicin 90-1330 gene cluster was found in ten ST28 strains, although some genes in the cluster were truncated in three of these isolates. The vast majority (101/102) of S. suis strains did not possess any of the genes encoding suicin 3908. In conclusion, this study indicates heterogeneous distribution of suicin genes in S. suis.

  4. Up-regulation of ICAM-1, CD11a/CD18 and CD11c/CD18 on human THP-1 monocytes stimulated by Streptococcus suis serotype 2

    PubMed Central

    AL-NUMANI, D; SEGURA, M; DORÉ, M; GOTTSCHALK, M

    2003-01-01

    Streptococcus suis serotype 2 is known to be a major pathogen of swine, causing mainly meningitis. It is also a zoonotic agent leading predominantly to meningitis in humans working in close contact with pigs. In this study, we investigated the ability of S. suis to up-regulate the expression of adhesion molecules involved in inflammation, using an enzyme-linked immunosorbent assay. S. suis serotype 2 stimulated the up-regulation of the expression of intercellular adhesion molecule-1 (ICAM-1, CD54), CD11a/CD18 and CD11c/CD18 on human THP-1 monocytes, but did not change that of ICAM-1, vascular cell adhesion molecule-1 (VCAM-1, CD106) and E-selectin (CD62E) on human endothelial cells. The up-regulation of adhesion molecules was time- and bacterial concentration-dependent, and cell wall components were largely responsible for such stimulation. To a lesser extent, purified haemolysin of S. suis also stimulated adhesion molecule expression. Stimulation of monocytes with strains of different origin showed that there was no clear tendency for human strains to induce a higher expression of adhesion molecules than strains from diseased pigs. Finally, monocytes stimulated with S. suis also showed an increase in adherence to endothelial cells. Hence, S. suis is capable of up-regulating important adhesion molecules involved in inflammation, which may result in an increased leucocyte recruitment into sites of infection, thus providing a possible mechanism for some of the inflammatory features of meningitis caused by this pathogen. PMID:12823280

  5. Serotype- and virulence-associated gene profile of Streptococcus suis isolates from pig carcasses in Chiang Mai Province, Northern Thailand

    PubMed Central

    WONGSAWAN, Kanruethai; GOTTSCHALK, Marcelo; THARAVICHITKUL, Prasit

    2014-01-01

    In this present study, the serotype of 40 Streptococcus suis isolates from submaxillary glands of pig carcasses sold in wet markets in Chiang Mai Province, northern Thailand, was investigated. Eleven serotypes, including types 2, 3, 4, 5, 7, 8, 9, 17, 21, 22 and 31, were found in the isolates by a Multiplex PCR combined with serum agglutination. Of the eleven serotypes present, type 3 was the most prevalent, while types 2, 4, 5 and 21 were of primary interest due to their human isolate serotype. The mrp+/epf − /sly − genotype was found to be the most prevalent genotype. This study indicates the importance of effective control of human S. suis infection due to raw pork or pig carcass handling in northern Thailand. PMID:25367105

  6. Detection of Multiple Parallel Transmission Outbreak of Streptococcus suis Human Infection by Use of Genome Epidemiology, China, 2005

    PubMed Central

    Du, Pengcheng; Zheng, Han; Zhou, Jieping; Lan, Ruiting; Ye, Changyun; Jing, Huaiqi; Jin, Dong; Cui, Zhigang; Bai, Xuemei; Liang, Jianming; Liu, Jiantao; Xu, Lei; Zhang, Wen; Chen, Chen

    2017-01-01

    Streptococcus suis sequence type 7 emerged and caused 2 of the largest human infection outbreaks in China in 1998 and 2005. To determine the major risk factors and source of the infections, we analyzed whole genomes of 95 outbreak-associated isolates, identified 160 single nucleotide polymorphisms, and classified them into 6 clades. Molecular clock analysis revealed that clade 1 (responsible for the 1998 outbreak) emerged in October 1997. Clades 2–6 (responsible for the 2005 outbreak) emerged separately during February 2002–August 2004. A total of 41 lineages of S. suis emerged by the end of 2004 and rapidly expanded to 68 genome types through single base mutations when the outbreak occurred in June 2005. We identified 32 identical isolates and classified them into 8 groups, which were distributed in a large geographic area with no transmission link. These findings suggest that persons were infected in parallel in respective geographic sites. PMID:27997331

  7. Porcine Dendritic Cells as an In Vitro Model to Assess the Immunological Behaviour of Streptococcus suis Subunit Vaccine Formulations and the Polarizing Effect of Adjuvants

    PubMed Central

    Martelet, Léa; Lacouture, Sonia; Goyette-Desjardins, Guillaume; Beauchamp, Guy; Surprenant, Charles; Gottschalk, Marcelo; Segura, Mariela

    2017-01-01

    An in vitro porcine bone marrow-derived dendritic cell (DC) culture was developed as a model for evaluating immune polarization induced by adjuvants when administered with immunogens that may become vaccine candidates if appropriately formulated. The swine pathogen Streptococcus suis was chosen as a prototype to evaluate proposed S. suis vaccine candidates in combination with the adjuvants Poly I:C, Quil A ®, Alhydrogel ®, TiterMax Gold ® and Stimune ®. The toll-like receptor ligand Poly I:C and the saponin Quil A ® polarized swine DC cytokines towards a type 1 phenotype, with preferential production of IL-12 and TNF-α. The water-in-oil adjuvants TiterMax Gold ® and Stimune ® favoured a type 2 profile as suggested by a marked IL-6 release. In contrast, Alhydrogel ® induced a type 1/type 2 mixed cytokine profile. The antigen type differently modified the magnitude of the adjuvant effect, but overall polarization was preserved. This is the first comparative report on swine DC immune activation by different adjuvants. Although further swine immunization studies would be required to better characterize the induced responses, the herein proposed in vitro model is a promising approach that helps assessing behaviour of the vaccine formulation rapidly at the pre-screening stage and will certainly reduce numbers of animals used while advancing vaccinology science. PMID:28327531

  8. In Vivo Pharmacodynamics of Cefquinome in a Neutropenic Mouse Thigh Model of Streptococcus suis Serotype 2 at Varied Initial Inoculum Sizes

    PubMed Central

    Guo, Chunna; Liao, Xiaoping; Wang, Mingru; Wang, Feng; Yan, Chaoqun; Xiao, Xia; Sun, Jiang

    2015-01-01

    Streptococcus suis serotype 2 is an emerging zoonotic pathogen and causes severe disease in both pigs and human beings. Cefquinome (CEQ), a fourth-generation cephalosporin, exhibits broad-spectrum activity against Gram-positive bacteria such as S. suis. This study evaluated the in vitro and in vivo antimicrobial activities of CEQ against four strains of S. suis serotype 2 in a murine neutropenic thigh infection model. We investigated the effect of varied inoculum sizes (106 to 108 CFU/thigh) on the pharmacokinetic (PK)/pharmacodynamic (PD) indices and magnitudes of a particular PK/PD index or dose required for efficacy. Dose fractionation studies included total CEQ doses ranging from 0.625 to 640 mg/kg/24 h. Data were analyzed via a maximum effect (Emax) model using nonlinear regression. The PK/PD studies demonstrated that the percentage of time that serum drug levels were above the MIC of free drug (%ƒT>MIC) in a 24-h dosing interval was the primary index driving the efficacy of both inoculum sizes (R2 = 91% and R2 = 63%). CEQ doses of 2.5 and 40 mg/kg body weight produced prolonged postantibiotic effects (PAEs) of 2.45 to 8.55 h. Inoculum sizes had a significant influence on CEQ efficacy. Compared to the CEQ exposure and dosages in tests using standard inocula, a 4-fold dose (P = 0.006) and a 2-fold exposure time (P = 0.01) were required for a 1-log kill using large inocula of 108 CFU/thigh. PMID:26666923

  9. The role of Isospora suis as a pathogen in conventional piglet production in Germany.

    PubMed

    Niestrath, M; Takla, M; Joachim, A; Daugschies, A

    2002-05-01

    In order to evaluate the prevalence of Isospora suis in conventional piglet production in Germany, pooled faecal samples from 327 pig litters from 18 pig production units (20-320 sows each) were examined. At least 10 litters from each farm were investigated. I. suis was present on 83% of the farms and 42.5% of the litters, the infection rate being highest in the third week of age (48.2%). I. suis was found more frequently in samples of diarrhoea than in firm faeces (49.2% compared to 22.2%). Twenty naturally infected piglets from six of these farms underwent examination post mortem, including histology, virology and bacteriology. Histological examination revealed atrophy of the villi in various degrees, mild crypt hyperplasia, fusion of the villi, metaplastic epithelium, erosions and necrosis, especially in the medium and the posterior jejunum and in the ileum. Asexual and sexual developmental stages of the parasite were found in varying numbers in the epithelium of the whole of the small intestine. Bacteria and viruses were mostly excluded as the cause of diarrhoea, and it was concluded that I. suis was the primary pathogen inducing distinct changes and clinical symptoms of diarrhoea.

  10. Polar Invasion and Translocation of Neisseria meningitidis and Streptococcus suis in a Novel Human Model of the Blood-Cerebrospinal Fluid Barrier

    PubMed Central

    Schwerk, Christian; Papandreou, Thalia; Schuhmann, Daniel; Nickol, Laura; Borkowski, Julia; Steinmann, Ulrike; Quednau, Natascha; Stump, Carolin; Weiss, Christel; Berger, Jürgen; Wolburg, Hartwig; Claus, Heike; Vogel, Ulrich; Ishikawa, Hiroshi

    2012-01-01

    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 plexus papilloma cells (HIBCPP), which display typical hallmarks of a BCSFB as the expression of junctional proteins and formation of tight junctions, a high electrical resistance and minimal levels of macromolecular flux when grown on transwell filters. Importantly, when challenged with the zoonotic pathogen Streptococcus suis or the human pathogenic bacterium Neisseria meningitidis the HIBCPP show polar bacterial invasion only from the physiologically relevant basolateral side. Meningococcal invasion is attenuated by the presence of a capsule and translocated N. meningitidis form microcolonies on the apical side of HIBCPP opposite of sites of entry. As a functionally relevant human model of the BCSFB the HIBCPP offer a wide range of options for analysis of disease-related mechanisms at the choroid plexus epithelium, especially involving human pathogens. PMID:22253884

  11. Structural and functional analysis of an anchorless fibronectin-binding protein FBPS from Gram-positive bacterium Streptococcus suis

    PubMed Central

    Musyoki, Abednego Moki; Shi, Zhongyu; Xuan, Chunling; Lu, Guangwen; Qi, Jianxun; Gao, Feng; Zheng, Beiwen; Zhang, Qiangmin; Li, Yan; Haywood, Joel; Liu, Cuihua; Yan, Jinghua; Shi, Yi; Gao, George F.

    2016-01-01

    The anchorless fibronectin-binding proteins (FnBPs) are a group of important virulence factors for which the structures are not available and the functions are not well defined. In this study we performed comprehensive studies on a prototypic member of this group: the fibronectin-/fibrinogen-binding protein from Streptococcus suis (FBPS). The structures of the N- and C-terminal halves (FBPS-N and FBPS-C), which together cover the full-length protein in sequence, were solved at a resolution of 2.1 and 2.6 Å, respectively, and each was found to be composed of two domains with unique folds. Furthermore, we have elucidated the organization of these domains by small-angle X-ray scattering. We further showed that the fibronectin-binding site is located in FBPS-C and that FBPS promotes the adherence of S. suis to host cells by attaching the bacteria via FBPS-N. Finally, we demonstrated that FBPS functions both as an adhesin, promoting S. suis attachment to host cells, and as a bacterial factor, activating signaling pathways via β1 integrin receptors to induce chemokine production. PMID:27834729

  12. Virulence Studies of Different Sequence Types and Geographical Origins of Streptococcus suis Serotype 2 in a Mouse Model of Infection

    PubMed Central

    Auger, Jean-Philippe; Fittipaldi, Nahuel; Benoit-Biancamano, Marie-Odile; Segura, Mariela; Gottschalk, Marcelo

    2016-01-01

    Multilocus sequence typing previously identified three predominant sequence types (STs) of Streptococcus suis serotype 2: ST1 strains predominate in Eurasia while North American (NA) strains are generally ST25 and ST28. However, ST25/ST28 and ST1 strains have also been isolated in Asia and NA, respectively. Using a well-standardized mouse model of infection, the virulence of strains belonging to different STs and different geographical origins was evaluated. Results demonstrated that although a certain tendency may be observed, S. suis serotype 2 virulence is difficult to predict based on ST and geographical origin alone; strains belonging to the same ST presented important differences of virulence and did not always correlate with origin. The only exception appears to be NA ST28 strains, which were generally less virulent in both systemic and central nervous system (CNS) infection models. Persistent and high levels of bacteremia accompanied by elevated CNS inflammation are required to cause meningitis. Although widely used, in vitro tests such as phagocytosis and killing assays require further standardization in order to be used as predictive tests for evaluating virulence of strains. The use of strains other than archetypal strains has increased our knowledge and understanding of the S. suis serotype 2 population dynamics. PMID:27409640

  13. Hearing and vestibular loss in Streptococcus suis infection from swine and traditional raw pork exposure in northern Thailand.

    PubMed

    Navacharoen, Niramon; Chantharochavong, V; Hanprasertpong, C; Kangsanarak, J; Lekagul, S

    2009-08-01

    To describe a series of 40 culture-proven, Streptococcus suis infected patients, focusing on route of entry and on hearing and vestibular dysfunction. Retrospective study of patient records in a tertiary care hospital in northern Thailand, 2003-2007. The majority (75 per cent) of cases were men with heavy drinking habits. A past history of the consumption of raw pork and/or pig's blood was found in 62.5 per cent of cases, whereas contact with swine products was found in 25 per cent. Thirty patients presented with sepsis, 19 with meningitis and 10 with infective endocarditis. The overall mortality rate was 20 per cent. After a mean follow up of 17 months, 73 per cent of the surviving meningitis cases had persistent sensorineural hearing loss and 50 per cent demonstrated vestibular impairment. In one patient, roentgenographic studies of the temporal bone were compatible with labyrinthitis ossificans. Permanent hearing loss and vestibular impairment occur frequently in persons surviving meningitis caused by Streptococcus suis.

  14. Screening of virulence-associated genes as a molecular typing method for characterization of Streptococcus suis isolates recovered from wild boars and pigs.

    PubMed

    Sánchez del Rey, Verónica; Fernández-Garayzábal, José F; Domínguez, Lucas; Gottschalk, Marcelo; Vela, Ana I

    2016-03-01

    Streptococcus suis is an important zoonotic pathogen associated with a wide range of diseases in pigs, but has also been isolated from wild animals such as rabbits and wild boars. In the current study, 126 S. suis isolates recovered from pigs (n = 85) and wild boars (n = 41) were tested by polymerase chain reaction (PCR) for the presence of nine virulence-associated genes. S. suis isolates from wild boars were differentiated by the lower detection rates of the epf, sly, mrp, sao and dltA genes (0%, 2.4%, 2.4%, 4.8% and 21.9%, respectively) compared with the isolates from pigs (56.5%, 75.3%, 56.5%, 88.2.0% and 88.2%, respectively). The differences in the content of these virulence-associated genes were statistically significant (P < 0.05). There was a correlation between the variants saoM and saoL and serotypes 2 and 9, respectively (P < 0.05). Isolates were classified into 31 virulence-associated gene profiles (VPs). Ten VPs were detected among wild boar isolates and 22 VPs among pig isolates, with only two VPs common to wild boars and pigs. The predominant VPs among isolates from wild boars (VP1, VP7) were different from those observed in pig isolates (VP16 and VP26). VP16 was detected exclusively in clinical pig isolates of serotype 9 and VP26 was detected in 71.4% of the serotype 2 clinical pig isolates. Further multilocus sequence typing (MLST) analysis showed a significant correlation association between certain VPs and STs (VP16 and VP17 with ST123 and ST125 and VP26 with ST1). In conclusion, the current study showed that combination of virulence-associated gene profiling and MLST analysis may provide more information of the relatedness of the S. suis strains from different animal species that could be useful for epidemiological purposes.

  15. Identification and characterization of two temperature-induced surface-associated proteins of Streptococcus suis with high homologies to members of the Arginine Deiminase system of Streptococcus pyogenes.

    PubMed

    Winterhoff, Nora; Goethe, Ralph; Gruening, Petra; Rohde, Manfred; Kalisz, Henryk; Smith, Hilde E; Valentin-Weigand, Peter

    2002-12-01

    The present study was performed to identify stress-induced putative virulence proteins of Streptococcus suis. For this, protein expression patterns of streptococci grown at 32, 37, and 42 degrees C were compared by one- and two-dimensional gel electrophoresis. Temperature shifts from 32 and 37 to 42 degrees C induced expression of two cell wall-associated proteins with apparent molecular masses of approximately 47 and 53 kDa. Amino-terminal sequence analysis of the two proteins indicated homologies of the 47-kDa protein with an ornithine carbamoyltransferase (OCT) from Streptococcus pyogenes and of the 53-kDa protein with the streptococcal acid glycoprotein (SAGP) from S. pyogenes, an arginine deiminase (AD) recently proposed as a putative virulence factor. Cloning and sequencing the genes encoding the putative OCT and AD of S. suis, octS and adiS, respectively, revealed that they had 81.2 (octS) and 80.2% (adiS) identity with the respective genes of S. pyogenes. Both genes belong to the AD system, also found in other bacteria. Southern hybridization analysis demonstrated the presence of the adiS gene in all 42 serotype 2 and 9 S. suis strains tested. In 9 of these 42 strains, selected randomly, we confirmed expression of the AdiS protein, homologous to SAGP, by immunoblot analysis using a specific antiserum against the SAGP of S. pyogenes. In all strains AD activity was detected. Furthermore, by immunoelectron microscopy using the anti-S. pyogenes SAGP antiserum we were able to demonstrate that the AdiS protein is expressed on the streptococcal surface in association with the capsular polysaccharides but is not coexpressed with them.

  16. Identification and Characterization of Two Temperature-Induced Surface-Associated Proteins of Streptococcus suis with High Homologies to Members of the Arginine Deiminase System of Streptococcus pyogenes

    PubMed Central

    Winterhoff, Nora; Goethe, Ralph; Gruening, Petra; Rohde, Manfred; Kalisz, Henryk; Smith, Hilde E.; Valentin-Weigand, Peter

    2002-01-01

    The present study was performed to identify stress-induced putative virulence proteins of Streptococcus suis. For this, protein expression patterns of streptococci grown at 32, 37, and 42°C were compared by one- and two-dimensional gel electrophoresis. Temperature shifts from 32 and 37 to 42°C induced expression of two cell wall-associated proteins with apparent molecular masses of approximately 47 and 53 kDa. Amino-terminal sequence analysis of the two proteins indicated homologies of the 47-kDa protein with an ornithine carbamoyltransferase (OCT) from Streptococcus pyogenes and of the 53-kDa protein with the streptococcal acid glycoprotein (SAGP) from S. pyogenes, an arginine deiminase (AD) recently proposed as a putative virulence factor. Cloning and sequencing the genes encoding the putative OCT and AD of S. suis, octS and adiS, respectively, revealed that they had 81.2 (octS) and 80.2% (adiS) identity with the respective genes of S. pyogenes. Both genes belong to the AD system, also found in other bacteria. Southern hybridization analysis demonstrated the presence of the adiS gene in all 42 serotype 2 and 9 S. suis strains tested. In 9 of these 42 strains, selected randomly, we confirmed expression of the AdiS protein, homologous to SAGP, by immunoblot analysis using a specific antiserum against the SAGP of S. pyogenes. In all strains AD activity was detected. Furthermore, by immunoelectron microscopy using the anti-S. pyogenes SAGP antiserum we were able to demonstrate that the AdiS protein is expressed on the streptococcal surface in association with the capsular polysaccharides but is not coexpressed with them. PMID:12446626

  17. Investigation into the role of catabolite control protein A in the metabolic regulation of Streptococcus suis serotype 2 using gene expression profile analysis.

    PubMed

    Lang, Xulong; Wan, Zhonghai; Pan, Ying; Wang, Xiuran; Wang, Xiaoxu; Bu, Zhaoyang; Qian, Jing; Zeng, Huazong; Wang, Xinglong

    2015-07-01

    Catabolite control protein A (CcpA) serves a key function in the catabolism of Streptococcus suis serotype 2 (S. suis 2) by affecting the biological function and metabolic regulatory mechanisms of this bacterium. The aim of the present study was to identify variations in CcpA expression in S. suis 2 using gene expression profile analysis. Using sequencing and functional analysis, CcpA was demonstrated to play a regulatory role in the expression and regulation of virulence genes, carbon metabolism and immunoregulation in S. suis 2. Gene Ontology and Kyto Encyclopedia of Genes and Genomes analyses indicated that CcpA in S. suis 2 is involved in the regulation of multiple metabolic processes. Furthermore, combined analysis of the transcriptome and metabolite data suggested that metabolites varied due to the modulation of gene expression levels under the influence of CcpA regulation. In addition, metabolic network analysis indicated that CcpA impacted carbon metabolism to a certain extent. Therefore, the present study has provided a more comprehensive analysis of the role of CcpA in the metabolic regulation of S. suis 2, which may facilitate future investigation into this mechanism. Furthermore, the results of the present study provide a foundation for further research into the regulatory function of CcpA and associated metabolic pathways in S. suis 2.

  18. Structural insight into the catalytic mechanism of gluconate 5-dehydrogenase from Streptococcus suis: Crystal structures of the substrate-free and quaternary complex enzymes

    PubMed Central

    Zhang, Qiangmin; Peng, Hao; Gao, Feng; Liu, Yiwei; Cheng, Hao; Thompson, John; Gao, George F

    2009-01-01

    Gluconate 5-dehydrogenase (Ga5DH) is an NADP(H)-dependent enzyme that catalyzes a reversible oxidoreduction reaction between d-gluconate and 5-keto-d-gluconate, thereby regulating the flux of this important carbon and energy source in bacteria. Despite the considerable amount of physiological and biochemical knowledge of Ga5DH, there is little physical or structural information available for this enzyme. To this end, we herein report the crystal structures of Ga5DH from pathogenic Streptococcus suis serotype 2 in both substrate-free and liganded (NADP+/d-gluconate/metal ion) quaternary complex forms at 2.0 Å resolution. Structural analysis reveals that Ga5DH adopts a protein fold similar to that found in members of the short chain dehydrogenase/reductase (SDR) family, while the enzyme itself represents a previously uncharacterized member of this family. In solution, Ga5DH exists as a tetramer that comprised four identical ∼29 kDa subunits. The catalytic site of Ga5DH shows considerable architectural similarity to that found in other enzymes of the SDR family, but the S. suis protein contains an additional residue (Arg104) that plays an important role in the binding and orientation of substrate. The quaternary complex structure provides the first clear crystallographic evidence for the role of a catalytically important serine residue and also reveals an amino acid tetrad RSYK that differs from the SYK triad found in the majority of SDR enzymes. Detailed analysis of the crystal structures reveals important contributions of Ca2+ ions to active site formation and of specific residues at the C-termini of subunits to tetramer assembly. Because Ga5DH is a potential target for therapy, our findings provide insight not only of catalytic mechanism, but also suggest a target of structure-based drug design. PMID:19177572

  19. Streptococcus suis serotype 2 strains isolated in Argentina (South America) are different from those recovered in North America and present a higher risk for humans

    PubMed Central

    Prieto, Monica; Xu, Jianguo; Zielinski, Gustavo; Auger, Jean-Philippe

    2016-01-01

    Introduction: Streptococcus suis serotype 2 is an important swine pathogen and emerging zoonotic agent causing meningitis and septicemia/septic shock. Strains are usually virulent (Eurasia) or of intermediate/low virulence (North America). Very few data regarding human and swine isolates from South America are available. Case presentation: Seventeen new human S. suis cases in Argentina (16 serotype 2 strains and a serotype 5 strain) are reported. Alongside, 14 isolates from pigs are analyzed: 12 from systemic disease, one from lungs and one from tonsils of a healthy animal. All human serotype 2 strains and most swine isolates are sequence type (ST) 1, as determined by multilocus sequence typing and present a mrp+/epf+/sly+ genotype typical of virulent Eurasian ST1 strains. The remaining two strains (recovered from swine lungs and tonsils) are ST28 and possess a mrp+/epf−/sly− genotype typical of low virulence North American strains. Representative human ST1 strains as well as one swine ST28 strain were analyzed by whole-genome sequencing and compared with genomes from GenBank. ST1 strains clustered together with three strains from Vietnam and this cluster is close to another one composed of 11 strains from the United Kingdom. Conclusion: Close contact with pigs/pork products, a good surveillance system, and the presence of potentially virulent Eurasian-like serotype 2 strains in Argentina may be an important factor contributing to the higher number of human cases observed. In fact, Argentina is now fifth among Western countries regarding the number of reported human cases after the Netherlands, France, the UK and Poland. PMID:28348788

  20. Streptococcus suis Bacterin and Subunit Vaccine Immunogenicities and Protective Efficacies against Serotypes 2 and 9▿†

    PubMed Central

    Baums, Christoph Georg; Kock, Christoph; Beineke, Andreas; Bennecke, Katharina; Goethe, Ralph; Schröder, Charlotte; Waldmann, Karl-Heinz; Valentin-Weigand, Peter

    2009-01-01

    Streptococcus suis causes numerous diseases in pigs, most importantly, meningitis, arthritis, septicemia, and bronchopneumonia. One of the major problems in modern swine production is the lack of a vaccine protecting against more than one S. suis serotype. The objective of this study was to determine the protective efficacy of a serotype 2 murein-associated protein (MAP) fraction subunit vaccine in comparison to that of a bacterin against experimental challenge with serotype 2 (containing muramidase-released protein [MRP], extracellular factor, and suilysin [SLY]) and serotype 9 (containing MRP variant MRP* and SLY) strains. MAP was shown to include different surface-associated proteins, such as the MRP and surface antigen one (SAO) expressed by both pathotypes used for challenge. The results of this study demonstrated that the serotype 2 bacterin induced protective immunity against homologous challenge. In contrast, the protective efficacy of the MAP subunit vaccine was low, though MAP immunization resulted in high serum immunoglobulin G2 titers against MRP and SAO. Importantly, immunization with bacterin but not with MAP induced opsonizing antibody titers against the serotype 2 strain, and these antibody titers were found to correlate with protection. However, after absorption with a nonencapsulated isogenic mutant, the sera from bacterin-immunized piglets failed to facilitate neutrophil killing, indicating that antibodies directed against capsule may not have been essential for opsonophagocytosis. Furthermore, induction of opsonizing antibodies against serotype 9 was not detectable in the group receiving bacterin or in the group receiving the MAP vaccine. In agreement, protection against the heterologous serotype 9 strain was low in both groups. Thus, identification of an antigen protecting against these two important S. suis pathotypes remains an important goal of future studies. PMID:19109449

  1. Identification of a Unique Amyloid Sequence in AA Amyloidosis of a Pig Associated With Streptococcus Suis Infection.

    PubMed

    Kamiie, J; Sugahara, G; Yoshimoto, S; Aihara, N; Mineshige, T; Uetsuka, K; Shirota, K

    2017-01-01

    Here we report a pig with amyloid A (AA) amyloidosis associated with Streptococcus suis infection and identification of a unique amyloid sequence in the amyloid deposits in the tissue. Tissues from the 180-day-old underdeveloped pig contained foci of necrosis and suppurative inflammation associated with S. suis infection. Congo red stain, immunohistochemistry, and electron microscopy revealed intense AA deposition in the spleen and renal glomeruli. Mass spectrometric analysis of amyloid material extracted from the spleen showed serum AA 2 (SAA2) peptide as well as a unique peptide sequence previously reported in a pig with AA amyloidosis. The common detection of the unique amyloid sequence in the current and past cases of AA amyloidosis in pigs suggests that this amyloid sequence might play a key role in the development of porcine AA amyloidosis. An in vitro fibrillation assay demonstrated that the unique AA peptide formed typically rigid, long amyloid fibrils (10 nm wide) and the N-terminus peptide of SAA2 formed zigzagged, short fibers (7 nm wide). Moreover, the SAA2 peptide formed long, rigid amyloid fibrils in the presence of sonicated amyloid fibrils formed by the unique AA peptide. These findings indicate that the N-terminus of SAA2 as well as the AA peptide mediate the development of AA amyloidosis in pigs via cross-seeding polymerization.

  2. Impact of an experimental PRRSV and Streptococcus suis coinfection on the pharmacokinetics of ceftiofur hydrochloride after intramuscular injection in pigs.

    PubMed

    Day, D N; Sparks, J W; Karriker, L A; Stalder, K J; Wulf, L W; Zhang, J; Kinyon, J M; Stock, M L; Gehring, R; Wang, C; Ellingson, J; Coetzee, J F

    2015-10-01

    This study determined the impact of porcine reproductive and respiratory syndrome virus (PRRSV) and Streptococcus suis coinfection on the pharmacokinetic (PK) profile of ceftiofur hydrochloride in pigs after intramuscular (i.m.) injection. Eighteen clinically normal crossbred gilts were assigned by weight into a challenge group (10 pigs) and control group (eight pigs). Pigs in both groups received a single i.m. injection of ceftiofur hydrochloride (Excenel RTU Sterile Suspension; Zoetis) at a 5 mg/kg BW dose. Serial blood samples were collected to characterize the plasma concentration curve. After a 10 days drug washout period, the challenge group was inoculated with 2 mL of PRRSV isolate VR-2385 (10(5.75) 50% tissue culture infective doses per mL) intranasally and 8 days later inoculated S. suis. When clinical disease was evident, the second PK assessment began in both challenge and control groups. Coinfected pigs demonstrated lower values of AUC and CMAX , but higher values of Cl/F and Vz/F indicating drug kinetics were altered by infection. The data from this study have implications on ceftiofur treatment regimens in diseased pigs. © 2015 John Wiley & Sons Ltd.

  3. Amplified fragment length polymorphism of Streptococcus suis strains correlates with their profile of virulence-associated genes and clinical background.

    PubMed

    Rehm, Thomas; Baums, Christoph G; Strommenger, Birgit; Beyerbach, Martin; Valentin-Weigand, Peter; Goethe, Ralph

    2007-01-01

    Amplified fragment length polymorphism (AFLP) typing was applied to 116 Streptococcus suis isolates with different clinical backgrounds (invasive/pneumonia/carrier/human) and with known profiles of virulence-associated genes (cps1, -2, -7 and -9, as well as mrp, epf and sly). A dendrogram was generated that allowed identification of two clusters (A and C) with different subclusters (A1, A2, C1 and C2) and two heterogeneous groups of strains (B and D). For comparison, three strains from each AFLP subcluster and group were subjected to multilocus sequence typing (MLST) analysis. The closest relationship and lowest diversity were found for patterns clustering within AFLP subcluster A1, which corresponded with sequence type (ST) complex 1. Strains within subcluster A1 were mainly invasive cps1 and mrp+ epf+ (or epf*) sly+ cps2+ strains of porcine or human origin. A new finding of this study was the clustering of invasive mrp* cps9 isolates within subcluster A2. MLST analysis suggested that A2 correlates with a single ST complex (ST87). In contrast to A1 and A2, subclusters C1 and C2 contained mainly pneumonia isolates of genotype cps7 or cps2 and epf- sly-. In conclusion, this study demonstrates that AFLP allows identification of clusters of S. suis strains with clinical relevance.

  4. A new recombinant SsnA protein combined with aluminum hydroxide protects mouse against Streptococcus suis.

    PubMed

    Gómez-Gascón, Lidia; Cardoso-Toset, Fernando; Amarilla, Paola Shyrley; Tarradas, Carmen; Carrasco, Librado; Olaya-Abril, Alfonso; Jiménez-Munguía, Irene; Rodríguez-Ortega, Manuel J; Luque, Inmaculada

    2014-12-05

    An experimental challenge in a mouse model was used to select the most effective adjuvant in a vaccine formulation with the surface-anchored DNA-nuclease (SsnA). We used a protocol based on clinical, histopathological, bacterial kinetics and immune response against S. suis serotype 2 in infected animals. The three adjuvants used, aluminum hydroxide (ALOH), incomplete Freund's adjuvant (FIA), oil-in-water adjuvant (OW) showed a protective effect against death by S. suis serotype 2 in this mouse model, although aluminum hydroxide revealed as the best option. Subsequently, in a second experimental assay, we showed that a recombinant SsnA protein combined with ALOH as adjuvant allowed a significant decrease of clinical and lesional findings in animals, faster reduction of the bacteria from organs and a highest humoral response against S. suis after 3 days post-infection. The results show that this combination (rSsnA+AlOH) could be a good vaccine formulation against S. suis, although further studies are necessary to evaluate their use for swine and human species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Live attenuated Salmonella enterica serovar Choleraesuis vaccine vector displaying regulated delayed attenuation and regulated delayed antigen synthesis to confer protection against Streptococcus suis in mice.

    PubMed

    Ji, Zhenying; Shang, Jing; Li, Yuan; Wang, Shifeng; Shi, Huoying

    2015-09-11

    Salmonella enterica serotype Choleraesuis (S. Choleraesuis) and Streptococcus suis (S. suis) are important swine pathogens. Development of a safe and effective attenuated S. Choleraesuis vaccine vector would open a new window to prevent and control pig diseases. To achieve this goal, the mannose and arabinose regulated delayed attenuated systems (RDAS), Δpmi and ΔPcrp::TT araC PBADcrp, were introduced into the wild type S. Choleraesuis strain C78-3. We also introduced ΔrelA::araC PBADlacI TT to achieve regulated delayed antigen synthesis and ΔasdA to constitute a balanced-lethal plasmid system. The safety and immunogenicity of the resulted RDAS S. Choleraesuis strain rSC0011 carrying 6-phosphogluconate dehydrogenase (6-PGD) of S. suis serotype 2 (SS2) were evaluated in vitro and in vivo. Compared with the wild type parent strain C78-3 and vaccine strain C500, a live attenuated S. Choleraesuis vaccine licensed for piglet in China, the results showed that the survival curves of the vaccine strain rSC0011 were similar to those of strains C78-3 and C500 at the early stage of infection, but lower than those of C78-3 and higher than those of C500 at the later stage in both porcine alveolar macrophages and peripheral porcine monocytes. The LD50 of the RDAS strains rSC0011 by oral route in mice was close to that of C500 and 10,000-fold higher than that of C78-3. Similar results were achieved by intraperitoneal (i.p.) route, suggesting that the RDAS strains rSC0011 achieved similar attenuation as C500. However, the RDAS strain rSC0011 was superior to C500 in colonization of Peyer's patches. Adult mice orally immunized with strain rSC0011 carrying a plasmid expression 6-phosphogluconate dehydrogenase (6-PGD) gene from SS2 developed strong immune responses against 6-PGD and Salmonella antigens, and conferred high protection against i.p. challenge with SS2.

  6. Molecular typing of Streptococcus suis isolates from Iberian pigs: a comparison with isolates from common intensively-reared commercial pig breeds.

    PubMed

    Sánchez Del Rey, V; Fernández-Garayzábal, J F; Bárcena, C; Briones, V; Domínguez, L; Gottschalk, M; Vela, A I

    2014-12-01

    The Iberian pig (IP) is a traditional Spanish breed variety of the domestic pig (Sus scrofa domesticus) with high economic importance because of the value of the dry-cured products in national and international markets. The genetic characteristics of tonsillar and clinical Streptococcus suis isolates from the IP maintained under extensive or intensive management conditions were investigated. S. suis isolates from IP pigs were compared with S. suis isolates from intensively-farmed pigs of common breeds (CBP). S. suis was isolated from 48.4% of the IP tonsils examined, indicating wide distribution among IP pigs. Serotypes 1 (9.4%), 2 (8.6%) and 9 (7%) were the most commonly found, although a high percentage of S. suis isolates were not typeable by coagglutination testing. No significant differences in carrier rates or serotype diversity were observed between management systems, indicating that intensive farming does not influence S. suis colonisation. Both pulsed-field gel electrophoresis and multiple-locus variable number tandem repeat analysis showed a serotype-based distribution of S. suis IP isolates. Serotypes 1 and 2 S. suis isolates were grouped in the same cluster, whereas isolates of serotypes 9 and 7 were assigned to another cluster. All clinical and most tonsillar serotype 2 IP isolates were assigned to sequence type 1 (ST1) and exhibited the virulence genotype mrp+/epf+/sly+, indicating a high distribution of this genetic lineage among IP as well as a population of serotype 2 common to IPs and CBPs. The only clinical isolate of serotype 9 from IP was assigned to ST123, a sequence type associated with clinical isolates in CBPs in Spain. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Evidence for Horizontal Transfer of SsuDAT1I Restriction-Modification Genes to the Streptococcus suis Genome

    PubMed Central

    Sekizaki, Tsutomu; Otani, Yoshiko; Osaki, Makoto; Takamatsu, Daisuke; Shimoji, Yoshihiro

    2001-01-01

    Different strains of Streptococcus suis serotypes 1 and 2 isolated from pigs either contained a restriction-modification (R-M) system or lacked it. The R-M system was an isoschizomer of Streptococcus pneumoniae DpnII, which recognizes nucleotide sequence 5′-GATC-3′. The nucleotide sequencing of the genes encoding the R-M system in S. suis DAT1, designated SsuDAT1I, showed that the SsuDAT1I gene region contained two methyltransferase genes, designated ssuMA and ssuMB, as does the DpnII system. The deduced amino acid sequences of M.SsuMA and M.SsuMB showed 70 and 90% identity to M.DpnII and M.DpnA, respectively. However, the SsuDAT1I system contained two isoschizomeric restriction endonuclease genes, designated ssuRA and ssuRB. The deduced amino acid sequence of R.SsuRA was 49% identical to that of R.DpnII, and R.SsuRB was 72% identical to R.LlaDCHI of Lactococcus lactis subsp. cremoris DCH-4. The four SsuDAT1I genes overlapped and were bounded by purine biosynthetic gene clusters in the following gene order: purF-purM-purN-purH-ssuMA-ssuMB-ssuRA-ssuRB-purD-purE. The G+C content of the SsuDAT1I gene region (34.1%) was lower than that of the pur region (48.9%), suggesting horizontal transfer of the SsuDAT1I system. No transposable element or long-repeat sequence was found in the flanking regions. The SsuDAT1I genes were functional by themselves, as they were individually expressed in Escherichia coli. Comparison of the sequences between strains with and without the R-M system showed that only the region from 53 bp upstream of ssuMA to 5 bp downstream of ssuRB was inserted in the intergenic sequence between purH and purD and that the insertion target site was not the recognition site of SsuDAT1I. No notable substitutions or insertions could be found, and the structures were conserved among all the strains. These results suggest that the SsuDAT1I system could have been integrated into the S. suis chromosome by an illegitimate recombination mechanism. PMID:11133943

  8. Quantitative susceptibility of Streptococcus suis strains isolated from diseased pigs in seven European countries to antimicrobial agents licensed in veterinary medicine.

    PubMed

    Wisselink, Henk J; Veldman, Kees T; Van den Eede, Chris; Salmon, Sarah A; Mevius, Dik J

    2006-03-10

    The susceptibility of Streptococcus suis strains (n=384) isolated from diseased pigs in seven European countries to 10 antimicrobial agents was determined. For that purpose a microbroth dilution method was used according to CLSI recommendations. The following antimicrobial agents were tested: ceftiofur, cefquinome, enrofloxacin, florfenicol, gentamicin, penicillin, spectinomycin, tetracycline, tilmicosin and trimethoprim/sulphamethoxazole. Using breakpoints established by CLSI for veterinary pathogens, all strains were susceptible to ceftiofur, florfenicol, enrofloxacin and penicillin. MIC-90 values of these antibiotics were < or = 0.03, 0.5, 2 and < or = 0.13 microg/mL, respectively. A low degree of resistance was observed for gentamicin (1.3%), spectinomycin (3.6%) and trimethoprim/sulphamethoxazole (6.0%). MIC-90 values of these antibiotics were 8, 16 and 2 microg/mL, respectively. A high level of resistance was observed for tetracycline (75.1%). A MIC-90 value of 64 microg/mL was found for this antibiotic. Serotype-associated differences in MIC-90 values were observed for tetracycline, tilmicosin and trimethoprim/suphamethoxazole.

  9. Cloning and nucleotide sequence of the gene encoding the 136-kilodalton surface protein (muramidase-released protein) of Streptococcus suis type 2.

    PubMed Central

    Smith, H E; Vecht, U; Gielkens, A L; Smits, M A

    1992-01-01

    We cloned and sequenced the gene encoding the muramidase-released protein (MRP) of a pathogenic Streptococcus suis type 2 strain to determine whether its amino acid sequence resembles that of proteins with known functions and to determine its function in virulence. The complete nucleotide sequence composing the gene and the regions flanking it was determined. The deduced amino acid sequence revealed the presence of a signal peptide at the N terminus and a cell envelope anchor at the C terminus, both of which resembled similar regions in several other surface proteins from gram-positive bacteria. The processed form of MRP has a length of 1,209 amino acids and a calculated molecular weight of 131,094. A highly repetitive region preceded the envelope anchor. The repeated units were preceded by a proline-rich stretch of amino acids (26 of 86). No overall homologies were observed between the amino acid sequence of MRP and protein sequences in the EMBL data bank. A particular region within the amino acid sequence, however, showed some similarity with the fibronectin-binding protein of Staphylococcus aureus. Binding of MRP to human fibronectin, however, could not be confirmed. Images PMID:1587602

  10. Molecular characterization of Streptococcus suis strains by 16S–23S intergenic spacer polymerase chain reaction and restriction fragment length polymorphism analysis

    PubMed Central

    Le Devendec, Laëtitia; Gottschalk, Marcelo; Kobisch, Marylène

    2006-01-01

    Abstract We developed a new molecular method of typing Streptococcus suis based on polymerase chain reaction (PCR) amplification of a large fragment of rRNA genes, including a part of the 16S and 23S genes and the 16S–23S intergenic spacer region (ISR), followed by restriction fragment length polymorphism (RFLP) analysis with RsaI or MboII endonuclease. The 16S–23S ISRs of 5 S. suis isolates were sequenced and compared. Size and sequence polymorphisms were observed between the S735 reference strain and the 4 wild-type strains. The genetic relationships between 138 independent S. suis strains belonging to various serotypes, isolated from swine or human cases, were determined. The discriminatory power of the method was > 0.95, the threshold value for interpreting typing results with confidence (0.954 with RsaI and 0.984 with RsaI plus MboII). The in vitro reproducibility was 100%. The strains isolated from humans were less genetically diverse than the strains isolated from pigs. For the first time, 2 molecular patterns (R6, M9) were significantly associated with S. suis serotype 2 strains. This genetic tool could be valuable in distinguishing individual isolates of S. suis during epidemiologic investigations. PMID:16639941

  11. HP1330 Contributes to Streptococcus suis Virulence by Inducing Toll-Like Receptor 2- and ERK1/2-Dependent Pro-inflammatory Responses and Influencing In Vivo S. suis Loads.

    PubMed

    Zhang, Qiang; Huang, Jingjing; Yu, Junping; Xu, Zhongmin; Liu, Liang; Song, Yajing; Sun, Xiaomei; Zhang, Anding; Jin, Meilin

    2017-01-01

    Streptococcus suis 2 (SS2) has evolved into a highly invasive pathogen responsible for two large-scale outbreaks of streptococcal toxic shock-like syndrome (STSLS) in China. Excessive inflammation stimulated by SS2 is considered a hallmark of STSLS, even it also plays important roles in other clinical symptoms of SS2-related disease, including meningitis, septicemia, and sudden death. However, the mechanism of SS2-caused excessive inflammation remains poorly understood. Here, a novel pro-inflammatory protein was identified (HP1330), which could induce robust expression of pro-inflammatory cytokines (TNF-α, MCP-1, and IL-1β) in RAW264.7 macrophages. To evaluate the role of HP1330 in SS2 virulence, an hp1330-deletion mutant (Δhp1330) was constructed. In vitro, hp1330 disruption led to a decreased pro-inflammatory ability of SS2 in RAW 264.7 macrophages. In vivo, Δhp1330 showed reduced lethality, pro-inflammatory activity, and bacterial loads in mice. To further elucidate the mechanism of HP1330-induced pro-inflammatory cytokine production, antibody blocking and gene-deletion experiments with macrophages were performed. The results revealed that the pro-inflammatory activity of HP1330 depended on the recognition of toll-like receptor 2 (TLR2). Furthermore, a specific inhibitor of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathways could significantly decrease HP1330-induced pro-inflammatory cytokine production, and western blot analysis showed that HP1330 could induce activation of the ERK1/2 pathway. Taken together, our findings demonstrate that HP1330 contributes to SS2 virulence by inducing TLR2- and ERK1/2-dependent pro-inflammatory cytokine production and influencing in vivo bacterial loads, implying that HP1330 may be associated with STSLS caused by SS2.

  12. Roles of the Putative Type IV-like Secretion System Key Component VirD4 and PrsA in Pathogenesis of Streptococcus suis Type 2

    PubMed Central

    Jiang, Xiaowu; Yang, Yunkai; Zhou, Jingjing; Zhu, Lexin; Gu, Yuanxing; Zhang, Xiaoyan; Li, Xiaoliang; Fang, Weihuan

    2016-01-01

    Streptococcus suis type 2 (SS2) is a zoonotic pathogen causing septic infection, meningitis and pneumonia in pigs and humans. SS2 may cause streptococcal toxic shock syndrome (STSS) probably due to excessive release of inflammatory cytokines. A previous study indicated that the virD4 gene in the putative type IV-like secretion system (T4SS) within the 89K pathogenicity island specific for recent epidemic strains contributed to the development of STSS. However, the functional basis of VirD4 in STSS remains unclear. Here we show that deletion of virD4 led to reduced virulence as shown by about 65% higher LD50, lower bacterial load in liver and brain, and lower level of expression of inflammatory cytokines in mice and cell lines than its parent strain. The ΔVirD4 mutant was more easily phagocytosed, suggesting its role as an anti-phagocytic factor. Oxidative stress that mimic bacterial exposure to respiratory burst of phagocytes upregulated expression of virD4. Proteomic analysis identified 10 secreted proteins of significant differences between the parent and mutant strains under oxidative stress, including PrsA, a peptidyl-prolyl isomerase. The SS2 PrsA expressed in E. coli caused a dose-dependent cell death and increased expression of proinflammatory IL-1β, IL-6 and TNF-α in murine macrophage cells. Our data provide novel insights into the contribution of the VirD4 factor to STSS pathogenesis, possibly via its anti-phagocytic activity, upregulation of its expression upon oxidative stress and its involvement in increased secretion of PrsA as a cell death inducer and proinflammatory effector. PMID:27995095

  13. A novel pro-inflammatory protein of Streptococcus suis 2 induces the Toll-like receptor 2-dependent expression of pro-inflammatory cytokines in RAW 264.7 macrophages via activation of ERK1/2 pathway.

    PubMed

    Zhang, Qiang; Yang, Yujie; Yan, Shuxian; Liu, Jiantao; Xu, Zhongmin; Yu, Junping; Song, Yajing; Zhang, Anding; Jin, Meilin

    2015-01-01

    Streptococcus suis 2 is an important swine pathogen and an emergent zoonotic pathogen. Excessive inflammation caused by S. suis is responsible for the high levels of early mortality observed in septic shock-like syndrome cases. However, the mechanisms through which S. suis 2 (SS2) causes excessive inflammation remain unclear. Thus, this study aimed to identify novel pro-inflammatory mediators that play important roles in the development of therapies against SS2 infection. In this study, the novel pro-inflammatory protein HP0459, which was encoded by the SSUSC84_0459 gene, was discovered. The stimulation of RAW 264.7 macrophages with recombinant HP0459 protein induced the expression of pro-inflammatory cytokines (IL-1β, MCP-1 and TNF-α). Compared with the wild-type (WT) strain, the isogenic knockout of HP0459 in SS2 led to reduced production of pro-inflammatory cytokines in RAW264.7 macrophages and in vivo. The pro-inflammatory activity of HP0459 was significantly reduced by an antibody against Toll-like receptor 2 (TLR2) in RAW264.7 macrophages and was lower in TLR2-deficient (TLR2-/-) macrophages than in WT macrophages. Furthermore, specific inhibitors of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathways significantly decreased the HP0459-induced pro-inflammatory cytokine production, and a western blot assay showed that HP0459 stimulation induced the activation of the ERK1/2 pathway. Taken together, our data indicate that HP0459 is a novel pro-inflammatory mediator of SS2 and induces TLR2-dependent pro-inflammatory activity in RAW264.7 macrophages through the ERK1/2 pathway.

  14. Multiple-class antimicrobial resistance surveillance in swine Escherichia coli F4, Pasteurella multocida and Streptococcus suis isolates from Ontario and the impact of the 2004-2006 Porcine Circovirus type-2 Associated Disease outbreak.

    PubMed

    Glass-Kaastra, Shiona K; Pearl, David L; Reid-Smith, Richard; McEwen, Beverly; Slavic, Durda; Fairles, Jim; McEwen, Scott A

    2014-02-01

    The objective of this work was to describe trends in multiple-class antimicrobial resistance present in clinical isolates of Escherichia coli F4, Pasteurella multocida and Streptococcus suis from Ontario swine 1998-2010. Temporal changes in multiple-class resistance varied by the pathogens examined; significant yearly changes were apparent for the E. coli and P. multocida data. Although not present in the E. coli data, significant increases in multiple-class resistance within P. multocida isolates occurred from 2003 to 2005, coinciding with the expected increase in antimicrobials used to treat clinical signs of Porcine Circovirus Associated Disease (PCVAD) before it was confirmed. Prospective temporal scan statistics for multiple-class resistance suggest that significant clusters of increased resistance may have been found in the spring of 2004; months before the identification of the PCVAD outbreak in the fall of 2004. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Simultaneous Quantification and Differentiation of Streptococcus suis Serotypes 2 and 9 by Quantitative Real-Time PCR, Evaluated in Tonsillar and Nasal Samples of Pigs

    PubMed Central

    Dekker, Niels; Daemen, Ineke; Verstappen, Koen; de Greeff, Astrid; Smith, Hilde; Duim, Birgitta

    2016-01-01

    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. PMID:27376336

  16. Assessment of the pathogenesis of Streptococcus suis type 2 infection in piglets for understanding streptococcal toxic shock-like syndrome, meningitis, and sequelae.

    PubMed

    Bi, Yuhai; Li, Jing; Yang, Limin; Zhang, Shuang; Li, Yun; Jia, Xiaojuan; Sun, Lei; Yin, Yanbo; Qin, Chuan; Wang, Beinan; Gao, George Fu; Liu, Wenjun

    2014-10-10

    Streptococcus suis type 2 (SS2) is an zoonotic pathogen that had caused outbreaks in 1998 and 2005 in China. It is still not very clear how the disease progresses into the streptococcal toxic shock-like syndrome (STSLS) or meningitis, as well as the sequelae from the survivals. The present study used piglets as infection model to systematically investigate the pathogenesis of the infection caused by the SS2 strain 05ZYH33. The infected piglets showed joint swelling, lameness, and crouch at beginning, then developed into septic-like shock syndrome (SLSS) or prostration syndrome, at last the survivals showed physical activity impairment. The morbidity and mortality were 100% (71% for SLSS, 29% for prostration syndrome) and 29%, respectively. The pigs exhibiting SLSS had deep invasive infections in tissues and organs, and displayed more severe bacteremia and cytokine secretion in the bloodstream and organs than pigs with prostration syndrome. Moreover, the polymorphisms in the toll-like receptor 1 (TLR1) and TLR2 genes varied between the pigs affected with SLSS and prostration syndrome. Several lines of evidence indicated that SS2 infection progression into SLSS or relatively lighter prostration syndrome in pigs is closely related to the degrees of bacteremia and cytokine storm, which may be inherently determined by the diversity of innate immunity-associated genes. Furthermore, brain lesions, such as venous thrombosis, may directly contribute to the sequelae in human cases, were identified in the pigs. These results might help us to further understand the pathogenesis of SS2 in humans.

  17. Streptococcus suis small RNA rss04 contributes to the induction of meningitis by regulating capsule synthesis and by inducing biofilm formation in a mouse infection model.

    PubMed

    Xiao, Genhui; Tang, Huanyu; Zhang, Shouming; Ren, Haiyan; Dai, Jiao; Lai, Liying; Lu, Chengping; Yao, Huochun; Fan, Hongjie; Wu, Zongfu

    2017-02-01

    Streptococcus suis (SS) is an important pathogen for pigs, and it is also considered as a zoonotic agent for humans. Meningitis is one of the most common features of the infection caused by SS, but little is known about the mechanisms of SS meningitis. Recent studies have revealed that small RNAs (sRNAs) have emerged as key regulators of the virulence in several bacteria. In the previous study, we reported that SS sRNA rss04 was up-regulated in pig cerebrospinal fluid and contributes to SS virulence in a zebrafish infection model. Here, we show that rss04 facilitates SS invasion of mouse brain and lung in vivo. Label-free quantitation mass spectrometry analysis revealed that rss04 regulates transcriptional regulator CcpA and several virulence factors including LuxS. Transmission electron microscope and Dot-blot analyses indicated that rss04 represses capsular polysaccharide (CPS) production, which in turn facilitates SS adherence and invasion of mouse brain microvascular endothelial cells bEnd.3 in vitro and activates the mRNA expression of TLR2, CCL2, IL-6 and TNF-α in mouse brain in vivo at 12h post-infection. In addition, rss04 positively regulates SS biofilm formation. Survival analysis of infected mice showed that biofilm state in brain contributes to SS virulence by intracranial subarachnoidal route of infection. Together, our data reveal that SS sRNA rss04 contributes to the induction of meningitis by regulating the CPS synthesis and by inducing biofilm formation, thereby increasing the virulence in a mouse infection model. To our knowledge, rss04 represents the first bacterial sRNA that plays definitive roles in bacterial meningitis.

  18. Serological patterns of Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae, Pasteurella multocida and Streptococcus suis in pig herds affected by pleuritis.

    PubMed

    Wallgren, Per; Nörregård, Erik; Molander, Benedicta; Persson, Maria; Ehlorsson, Carl-Johan

    2016-10-04

    Respiratory illness is traditionally regarded as the disease of the growing pig, and has historically mainly been associated to bacterial infections with focus on Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. These bacteria still are of great importance, but continuously increasing herd sizes have complicated the scenario and the influence of secondary invaders may have been increased. The aim of this study was to evaluate the presence of A. pleuropneumoniae and M. hyopneumoniae, as well as that of the secondary invaders Pasteurella multocida and Streptococcus suis by serology in four pig herds (A-D) using age segregated rearing systems with high incidences of pleuritic lesions at slaughter. Pleuritic lesions registered at slaughter ranged from 20.5 to 33.1 % in the four herds. In herd A, the levels of serum antibodies to A. pleuropneumoniae exceeded A450 > 1.5, but not to any other microbe searched for. The seroconversion took place early during the fattening period. Similar levels of serum antibodies to A. pleuropneumoniae were also recorded in herd B, with a subsequent increase in levels of antibodies to P. multocida. Pigs seroconverted to both agents during the early phase of the fattening period. In herd C, pigs seroconverted to P. multocida during the early phase of the fattening period and thereafter to A. pleuropneumoniae. In herd D, the levels of antibodies to P. multocida exceeded A450 > 1.0 in absence (A450 < 0.5) of antibodies to A. pleuropneumoniae. The levels of serum antibodies to M. hyopneumoniae and to S. suis remained below A450 < 1.0 in all four herds. Pigs seroconverted to M. hyopneumoniae late during the rearing period (herd B-D), or not at all (herd A). Different serological patterns were found in the four herds with high levels of serum antibodies to A. pleuropneumoniae and P. multocida, either alone or in combination with each other. Seroconversion to M. hyopneumoniae late during the rearing period or

  19. Functional definition and global regulation of Zur, a zinc uptake regulator in a Streptococcus suis serotype 2 strain causing streptococcal toxic shock syndrome.

    PubMed

    Feng, Youjun; Li, Ming; Zhang, Huimin; Zheng, Beiwen; Han, Huiming; Wang, Changjun; Yan, Jinghua; Tang, Jiaqi; Gao, George F

    2008-11-01

    Zinc is an essential trace element for all living organisms and plays pivotal roles in various cellular processes. However, an excess of zinc is extremely deleterious to cells. Bacteria have evolved complex machineries (such as efflux/influx systems) to control the concentration at levels appropriate for the maintenance of zinc homeostasis in cells and adaptation to the environment. The Zur (zinc uptake regulator) protein is one of these functional members involved in the precise control of zinc homeostasis. Here we identified a zur homologue designated 310 from Streptococcus suis serotype 2, strain 05ZYH33, a highly invasive isolate causing streptococcal toxic shock syndrome. Biochemical analysis revealed that the protein product of gene 310 exists as a dimer form and carries zinc ions. An isogenic gene replacement mutant of gene 310, the Delta310 mutant, was obtained by homologous recombination. Physiological tests demonstrated that the Delta310 mutant is specifically sensitive to Zn(2+), while functional complementation of the Delta310 mutant can restore its duration capability, suggesting that 310 is a functional member of the Zur family. Two-dimensional electrophoresis indicated that nine proteins in the Delta310 mutant are overexpressed in comparison with those in the wild type. DNA microarray analyses suggested that 121 genes in the Delta310 mutant are affected, of which 72 genes are upregulated and 49 are downregulated. The transcriptome of S. suis serotype 2 with high Zn(2+) concentrations also showed 117 differentially expressed genes, with 71 upregulated and 46 downregulated. Surprisingly, more than 70% of the genes differentially expressed in the Delta310 mutant were the same as those in S. suis serotype 2 that were differentially expressed in response to high Zn(2+) concentration, consistent with the notion that 310 is involved in zinc homeostasis. We thus report for the first time a novel zinc-responsive regulator, Zur, from Streptococcus suis

  20. Group B Streptococcus and Streptococcus suis Capsular Polysaccharides Induce Chemokine Production by Dendritic Cells via Toll-Like Receptor 2- and MyD88-Dependent and -Independent Pathways

    PubMed Central

    Calzas, Cynthia; Goyette-Desjardins, Guillaume; Lemire, Paul; Gagnon, Fleur; Lachance, Claude; Van Calsteren, Marie-Rose

    2013-01-01

    Streptococcus agalactiae (also known as group B Streptococcus [GBS]) and Streptococcus suis are encapsulated streptococci causing severe septicemia and meningitis. Bacterial capsular polysaccharides (CPSs) are poorly immunogenic, but anti-CPS antibodies are essential to the host defense against encapsulated bacteria. The mechanisms underlying anti-CPS antibody responses are not fully elucidated, but the biochemistry of CPSs, particularly the presence of sialic acid, may have an immunosuppressive effect. We investigated the ability of highly purified S. suis and GBS native (sialylated) CPSs to activate dendritic cells (DCs), which are crucial actors in the initiation of humoral immunity. The influence of CPS biochemistry was studied using CPSs extracted from different serotypes within these two streptococcal species, as well as desialylated CPSs. No interleukin-1β (IL-1β), IL-6, IL-12p70, tumor necrosis factor alpha (TNF-α), or IL-10 production was observed in S. suis or GBS CPS-stimulated DCs. Moreover, these CPSs exerted immunosuppressive effects on DC activation, as a diminution of gamma interferon (IFN-γ)-induced B cell-activating factor of the tumor necrosis factor family (BAFF) expression was observed in CPS-pretreated cells. However, S. suis and GBS CPSs induced significant production of CCL3, via partially Toll-like receptor 2 (TLR2)- and myeloid differentiation factor 88 (MyD88)-dependent pathways, and CCL2, via TLR-independent mechanisms. No major influence of CPS biochemistry was observed on the capacity to induce chemokine production by DCs, indicating that DCs respond to these CPSs in a patterned way rather than a structure-dedicated manner. PMID:23774593

  1. Ecology and pathogenicity of gastrointestinal Streptococcus bovis.

    PubMed

    Herrera, Paul; Kwon, Young Min; Ricke, Steven C

    2009-01-01

    Streptococcus bovis is an indigenous resident in the gastrointestinal tracts of both humans and animals. S. bovis is one of the major causes of bacterial endocarditis and has been implicated in the incidence of human colon cancer, possibly due to chronic inflammatory response at the site of intestinal colonization. Certain feeding regimens in ruminants can lead to overgrowth of S. bovis in the rumen, resulting in the over-production of lactate and capsular polysaccharide causing acute ruminal acidosis and bloat, respectively. There are multiple strategies in controlling acute lactic acidosis and bloat. The incidence of the two diseases may be controlled by strict dietary management. Gradual introduction of grain-based diets and the feeding of coarsely chopped roughage decrease the incidence of the two disease entities. Ionophores, which have been used to enhance feed conversion and growth rate in cattle, have been shown to inhibit the growth of lactic acid bacteria in the rumen. Other methods of controlling lactic acid bacteria in the ruminal environment (dietary supplementation of long-chain fatty acids, induction of passive and active immune responses to the bacteria, and the use of lytic bacteriophages) have also been investigated. It is anticipated that through continued in-depth ecological analysis of S. bovis the characteristics responsible for human and animal pathogenesis would be sufficiently identified to a point where more effective control strategies for the control of this bacteria can be developed.

  2. Investigation of Pathogenesis of H1N1 Influenza Virus and Swine Streptococcus suis Serotype 2 Co-Infection in Pigs by Microarray Analysis.

    PubMed

    Lin, Xian; Huang, Canhui; Shi, Jian; Wang, Ruifang; Sun, Xin; Liu, Xiaokun; Zhao, Lianzhong; Jin, Meilin

    2015-01-01

    Swine influenza virus and Streptococcus suis are two important contributors to the porcine respiratory disease complex, and both have significant economic impacts. Clinically, influenza virus and Streptococcus suis co-infections in pigs are very common, which often contribute to severe pneumonia and can increase the mortality. However, the co-infection pathogenesis in pigs is unclear. In the present study, co-infection experiments were performed using swine H1N1 influenza virus and Streptococcus suis serotype 2 (SS2). The H1N1-SS2 co-infected pigs exhibited more severe clinical symptoms, serious pathological changes, and robust apoptosis of lungs at 6 days post-infection compared with separate H1N1 and SS2 infections. A comprehensive gene expression profiling using a microarray approach was performed to investigate the global host responses of swine lungs against the swine H1N1 infection, SS2 infection, co-infection, and phosphate-buffered saline control. Results showed 457, 411, and 844 differentially expressed genes in the H1N1, SS2, and H1N1-SS2 groups, respectively, compared with the control. Noticeably, genes associated with the immune, inflammatory, and apoptosis responses were highly overexpressed in the co-infected group. Pathway analysis indicated that the cytokine-cytokine receptor interactions, MAPK, toll-like receptor, complement and coagulation cascades, antigen processing and presentation, and apoptosis pathway were significantly regulated in the co-infected group. However, the genes related to these were less regulated in the separate H1N1 and SS2 infection groups. This observation suggested that a certain level of synergy was induced by H1N1 and SS2 co-infection with significantly stronger inflammatory and apoptosis responses, which may lead to more serious respiratory disease syndrome and pulmonary pathological lesion.

  3. Investigation of Pathogenesis of H1N1 Influenza Virus and Swine Streptococcus suis Serotype 2 Co-Infection in Pigs by Microarray Analysis

    PubMed Central

    Shi, Jian; Wang, Ruifang; Sun, Xin; Liu, Xiaokun; Zhao, Lianzhong; Jin, Meilin

    2015-01-01

    Swine influenza virus and Streptococcus suis are two important contributors to the porcine respiratory disease complex, and both have significant economic impacts. Clinically, influenza virus and Streptococcus suis co-infections in pigs are very common, which often contribute to severe pneumonia and can increase the mortality. However, the co-infection pathogenesis in pigs is unclear. In the present study, co-infection experiments were performed using swine H1N1 influenza virus and Streptococcus suis serotype 2 (SS2). The H1N1-SS2 co-infected pigs exhibited more severe clinical symptoms, serious pathological changes, and robust apoptosis of lungs at 6 days post-infection compared with separate H1N1 and SS2 infections. A comprehensive gene expression profiling using a microarray approach was performed to investigate the global host responses of swine lungs against the swine H1N1 infection, SS2 infection, co-infection, and phosphate-buffered saline control. Results showed 457, 411, and 844 differentially expressed genes in the H1N1, SS2, and H1N1-SS2 groups, respectively, compared with the control. Noticeably, genes associated with the immune, inflammatory, and apoptosis responses were highly overexpressed in the co-infected group. Pathway analysis indicated that the cytokine–cytokine receptor interactions, MAPK, toll-like receptor, complement and coagulation cascades, antigen processing and presentation, and apoptosis pathway were significantly regulated in the co-infected group. However, the genes related to these were less regulated in the separate H1N1 and SS2 infection groups. This observation suggested that a certain level of synergy was induced by H1N1 and SS2 co-infection with significantly stronger inflammatory and apoptosis responses, which may lead to more serious respiratory disease syndrome and pulmonary pathological lesion. PMID:25906258

  4. Evaluation of the antibody response in pigs vaccinated against Streptococcus suis capsular type 2 using a double-antibody sandwich enzyme-linked immunosorbent assay.

    PubMed Central

    Blouin, C; Higgins, R; Gottschalk, M; Simard, J

    1994-01-01

    A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) was standardized for the detection of specific antibodies following vaccination with Streptococcus suis capsular type 2 bacterins. No statistically significant increase of antibody titers was detected in vaccinated piglets compared to the nonvaccinated control group, even if a minority of piglets demonstrated an important postvaccinal response. Three of four vaccinated sows showed a low antibody response to vaccine and specific immunity was detected in piglets of only one litter of these three sows. Passive protection studies showed that none of the sera from vaccinated piglets were protective for mice whereas serum obtained from hyperimmunized pigs gave protection. PMID:8143253

  5. Genetic analysis of Streptococcus suis isolates recovered from diseased and healthy carrier pigs at different stages of production on a pig farm.

    PubMed

    Luque, Inmaculada; Blume, Verena; Borge, Carmen; Vela, Ana I; Perea, J A; Márquez, José M; Fernández-Garayzábal, José F; Tarradas, Carmen

    2010-12-01

    Streptococcus suis isolates from pigs at different stages of production on a farrow-to-finish farm were characterised by serotyping, pulsed-field gel electrophoresis (PFGE) and production of muramidase-released protein, extracellular factor and suilysin. S. suis was isolated from the tonsils of 81/287 (28.2%) healthy pigs: 16/47 (34%) post-weaning, 18/47 (38.3%) transition, 18/47 (38.3%) fattening and 29/146 (19.9%) sows. A total of 127 S. suis isolates were analysed: 14 from diseased pigs at the post-weaning stage and 113 from the tonsils of healthy pigs. Serotypes 2, 4, 9, 14 and 1/14 were isolated from both diseased and healthy pigs. A total of 83 PFGE profiles were obtained; most isolates (95.2%) were grouped into three clusters (A-C). Animals at different production stages harboured isolates with similar phenotypic and genetic profiles, highlighting the importance of healthy animals in the maintenance of strains responsible for outbreaks of clinical disease.

  6. Crystal structures of Streptococcus suis mannonate dehydratase (ManD) and its complex with substrate: genetic and biochemical evidence for a catalytic mechanism.

    PubMed

    Zhang, Qiangmin; Gao, Feng; Peng, Hao; Cheng, Hao; Liu, Yiwei; Tang, Jiaqi; Thompson, John; Wei, Guohua; Zhang, Jingren; Du, Yuguo; Yan, Jinghua; Gao, George F

    2009-09-01

    Mannonate dehydratase (ManD) is found only in certain bacterial species, where it participates in the dissimilation of glucuronate. ManD catalyzes the dehydration of d-mannonate to yield 2-keto-3-deoxygluconate (2-KDG), the carbon and energy source for growth. Selective inactivation of ManD by drug targeting is of therapeutic interest in the treatment of human Streptococcus suis infections. Here, we report the overexpression, purification, functional characterization, and crystallographic structure of ManD from S. suis. Importantly, by Fourier transform mass spectrometry, we show that 2-KDG is formed when the chemically synthesized substrate (d-mannonate) is incubated with ManD. Inductively coupled plasma-mass spectrometry revealed the presence of Mn(2+) in the purified protein, and in the solution state catalytically active ManD exists as a homodimer of two 41-kDa subunits. The crystal structures of S. suis ManD in native form and in complex with its substrate and Mn(2+) ion have been solved at a resolution of 2.9 A. The core structure of S. suis ManD is a TIM barrel similar to that of other members of the xylose isomerase-like superfamily. Structural analyses and comparative amino acid sequence alignments provide evidence for the importance of His311 and Tyr325 in ManD activity. The results of site-directed mutagenesis confirmed the functional role(s) of these residues in the dehydration reaction and a plausible mechanism for the ManD-catalyzed reaction is proposed.

  7. hsdS, Belonging to the Type I Restriction-Modification System, Contributes to the Streptococcus suis Serotype 2 Survival Ability in Phagocytes

    PubMed Central

    Xu, Bin; Zhang, Ping; Li, Weiyi; Liu, Rui; Tang, Jinsheng; Fan, Hongjie

    2017-01-01

    Streptococcus suis serotype 2 (SS2) is an important zoonotic agent in swine and humans. Anti-phagocytosis and survival in phagocytic cells and whole blood is essential for bacteria to be pathogenic. In this study, the host specificity determinant specificity subunit (coded by hsdS) of the Type I Restriction-Modification system and two peptidoglycan-binding proteins (coded by lysM and lysM′, respectively), which were simultaneously found to be subjected to transcript-level influence by hsdS, were identified to facilitate the anti-phagocytosis of SS2 to a microglia cell line BV2. Furthermore, they significantly enhanced its survival in BV2, whole blood, and a peroxidation environment (H2O2) (p < 0.05), yet not in the acidic condition based on statistical analysis of the characteristic differences between gene mutants and wild-type SS2. In contrast, another specificity subunit, coded by hsdS′, that belonged to the same Type I Restriction-Modification system, only significantly reduced the survival ability of SS2 in the acidic condition when in the form of a gene-deleted mutant (p < 0.05), but it did not significantly influence the survival ability in other conditions mentioned above or have enhanced anti-phagocytosis action when compared with wild-type SS2. In addition, the mutation of hsdS significantly enhanced the secretion of nitric oxide and TNF-α by BV2 with SS2 incubation (p < 0.05). The SS2 was tested, and it failed to stimulate BV2 to produce IFN-γ. These results demonstrated that hsdS contributed to bacterial anti-phagocytosis and survival in adverse host environments through positively impacting the transcription of two peptidoglycan-binding protein genes, enhancing resistance to reactive oxygen species, and reducing the secretion of TNF-α and nitric oxide by phagocytes. These findings revealed new mechanisms of SS2 pathogenesis. PMID:28848531

  8. Parallel Evolution of Streptococcus pneumoniae and Streptococcus mitis to Pathogenic and Mutualistic Lifestyles

    PubMed Central

    Riley, David R.; Jensen, Anders; Brüggemann, Holger; Tettelin, Hervé

    2014-01-01

    ABSTRACT The bacterium Streptococcus pneumoniae is one of the leading causes of fatal infections affecting humans. Intriguingly, phylogenetic analysis shows that the species constitutes one evolutionary lineage in a cluster of the otherwise commensal Streptococcus mitis strains, with which humans live in harmony. In a comparative analysis of 35 genomes, including phylogenetic analyses of all predicted genes, we have shown that the pathogenic pneumococcus has evolved into a master of genomic flexibility while lineages that evolved into the nonpathogenic S. mitis secured harmonious coexistence with their host by stabilizing an approximately 15%-reduced genome devoid of many virulence genes. Our data further provide evidence that interspecies gene transfer between S. pneumoniae and S. mitis occurs in a unidirectional manner, i.e., from S. mitis to S. pneumoniae. Import of genes from S. mitis and other mitis, anginosus, and salivarius group streptococci ensured allelic replacements and antigenic diversification and has been driving the evolution of the remarkable structural diversity of capsular polysaccharides of S. pneumoniae. Our study explains how the unique structural diversity of the pneumococcal capsule emerged and conceivably will continue to increase and reveals a striking example of the fragile border between the commensal and pathogenic lifestyles. While genomic plasticity enabling quick adaptation to environmental stress is a necessity for the pathogenic streptococci, the commensal lifestyle benefits from stability. PMID:25053789

  9. First insights into the protective effects of a recombinant swinepox virus expressing truncated MRP of Streptococcus suis type 2 in mice.

    PubMed

    Huang, Dongyan; Zhu, Haodan; Lin, Huixing; Xu, Jiarong; Lu, Chengping

    2012-01-01

    To explore the potential of the swinepox virus (SPV) as vector for Streptococcus suis vaccines, a vector system was developed for the construction of a recombinant SPV carrying bacterial genes. Using this system, a recombinant virus expressing truncated muramidase-released protein (MRP) of S. suis type 2 (SS2), designated rSPV-MRP, was produced and identified by PCR, western blotting and immunofluorescence assays. The rSPV-MRP was found to be only slightly attenuated in PK-15 cells, when compared with the wild-type virus. After immunization intramuscularly with rSPV-MRP, SS2 inactive vaccine (positive control), wild-type SPV (negative control) and PBS (blank control) respectively, all CD1 mice were challenged with a lethal dose or a sublethal dose of SS2 highly virulent strain ZY05719. While SS2 inactive vaccine protected all mice, immunization with rSPV-MRP resulted in 60% survival and protected mice against a lethal dose of the highly virulent SS2 strain, compared with the negative control (P < 0.05). Our data indicate that animals immunized with rSPV-MRP had a significantly reduced bacterial burden in all organs examined, compared to negative controls and blank controls (P <0.05). Antibody titers of the rSPV-MRP-vaccinated group were significantly higher (P <0.001), when compared to negative controls and blank controls. Antibody titers were also significantly higher in the vaccinated group at all time points post-vaccination (P <0.001), compared with the positive controls. These initial results demonstrated that the rSPV-MRP provided mice with protection from systemic SS2 infection. If SPV recombinants have the potential as S. suis vaccines for the use in pigs has to be evaluated in further studies.

  10. Assessment of protective efficacy of live and killed vaccines based on a non-encapsulated mutant of Streptococcus suis serotype 2.

    PubMed

    Wisselink, Henk J; Stockhofe-Zurwieden, Norbert; Hilgers, Luuk A T; Smith, Hilde E

    2002-01-03

    The protective efficacy of a live and killed non-encapsulated isogenic mutant of Streptococcus suis serotype 2 was determined in pigs, and compared with the efficacy of the capsulated wild-type strain. SPF pigs were vaccinated twice intramuscularly at 4 and 7 weeks of age with a dose of 1 x 10(9) formalin-killed CFU of the wild-type (WT-BAC), formalin-killed non-encapsulated mutant (CM-BAC) or live non-encapsulated mutant (CM-LIVE) strain. After 2 weeks, vaccinated pigs and non-vaccinated controls were challenged intravenously with 1 x 10(7) CFU of the homologous, wild-type S. suis serotype 2 strain. Protection was evaluated by clinical, bacteriological, serological and post-mortem examinations. All pigs vaccinated with WT-BAC were completely protected against challenge with the homologous serotype. Pigs vaccinated with CM-BAC were partially protected. Although all pigs vaccinated with CM-BAC survived the challenge, four out of five pigs developed clinical signs of disease for several days. Compared to the WT-BAC and CM-BAC, the CM-LIVE vaccine was less protective. Two out of five pigs vaccinated with CM-LIVE died in the course of the experiment and all of them developed specific clinical signs of disease for several days. The protective efficacy of the vaccines could be associated with serum antibody titers. Antibody titers against cells of wild-type and non-encapsulated mutant strains as well as against muramidase-released proteins (MRP) were high in pigs vaccinated with WT-BAC and CM-BAC. Pigs vaccinated with CM-LIVE showed lower antibody titers. Antibody titers against purified capsular polysaccharides (CPS) of S. suis serotype 2 were only found in pigs vaccinated with WT-BAC. These findings indicate that CPS and other bacterial components of WT-BAC are probably essential for full protection against homologous challenge.

  11. Antimicrobial susceptibility of Escherichia coli F4, Pasteurella multocida, and Streptococcus suis isolates from a diagnostic veterinary laboratory and recommendations for a surveillance system.

    PubMed

    Glass-Kaastra, Shiona K; Pearl, David L; Reid-Smith, Richard J; McEwen, Beverly; Slavic, Durda; McEwen, Scott A; Fairles, Jim

    2014-04-01

    Antimicrobial susceptibility data on Escherichia coli F4, Pasteurella multocida, and Streptococcus suis isolates from Ontario swine (January 1998 to October 2010) were acquired from a comprehensive diagnostic veterinary laboratory in Ontario, Canada. In relation to the possible development of a surveillance system for antimicrobial resistance, data were assessed for ease of management, completeness, consistency, and applicability for temporal and spatial statistical analyses. Limited farm location data precluded spatial analyses and missing demographic data limited their use as predictors within multivariable statistical models. Changes in the standard panel of antimicrobials used for susceptibility testing reduced the number of antimicrobials available for temporal analyses. Data consistency and quality could improve over time in this and similar diagnostic laboratory settings by encouraging complete reporting with sample submission and by modifying database systems to limit free-text data entry. These changes could make more statistical methods available for disease surveillance and cluster detection.

  12. Functional definition of LuxS, an autoinducer-2 (AI-2) synthase and its role in full virulence of Streptococcus suis serotype 2.

    PubMed

    Cao, Min; Feng, Youjun; Wang, Changjun; Zheng, Feng; Li, Ming; Liao, Hui; Mao, Yinghua; Pan, Xiuzhen; Wang, Jing; Hu, Dan; Hu, Fuquan; Tang, Jiaqi

    2011-12-01

    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 (SS2) in China. A luxS null mutant (ΔluxS) of 05ZYH33 strain was obtained using an approach of homologous recombination. LuxS was determined to be required for AI-2 production in 05ZYH33 strain of S. suis 2. Inactivation of luxS gene led to a wide range of phenotypic changes including thinner capsular walls, increased tolerance to H(2)O(2), reduced adherence capacity to epithelial cells, etc. In particular, loss of LuxS impaired dramatically its full virulence of SS2 in experimental model of piglets, and functional complementation restored it nearly to the level of parent strain. Genome-wide transcriptome analyses suggested that some known virulence factors such as CPS are down-regulated in the ΔluxS mutant, which might in part explain virulence attenuation by luxS deletion. Similarly, 29 of 71 genes with different expression level were proposed to be targets candidate regulated by LuxS/AI-2-dependent quorum sensing.

  13. Relatedness of Streptococcus suis Isolates of Various Serotypes and Clinical Backgrounds as Evaluated by Macrorestriction Analysis and Expression of Potential Virulence Traits

    PubMed Central

    Allgaier, Achim; Goethe, Ralph; Wisselink, Henk J.; Smith, Hilde E.; Valentin-Weigand, Peter

    2001-01-01

    We evaluated the genetic diversity of Streptococcus suis isolates of different serotypes by macrorestriction analysis and elucidated possible relationships between the genetic background, expression of potential virulence traits, and source of isolation. Virulence traits included expression of serotype-specific polysaccharides, muramidase-released protein (MRP), extracellular protein factor (EF), hemolysin activity, and adherence to epithelial cells. Macrorestriction analysis of streptococcal DNA digested with restriction enzymes SmaI and ApaI allowed differentiation of single isolates that could be assigned to four major clusters, named A1, A2, B1, and B2. Comparison of the genotypic and phenotypic features of the isolates with their source of isolation showed that (i) the S. suis population examined, which originated mainly from German pigs, exhibited a genetic diversity and phenotypic patterns comparable to those found for isolates from other European countries; (ii) certain phenotypic features, such as the presence of capsular antigens of serotypes 2, 1, and 9, expression of MRP and EF, and hemolysin activity (and in particular, combinations of these features), were strongly associated with the clinical background of meningitis and septicemia; and (iii) isolates from pigs with meningitis and septicemia showed a significantly higher degree of genetic homogeneity compared to that for isolates from pigs with pneumonia and healthy pigs. Since the former isolates are considered highly virulent, this supports the theory of a clonal relationship among highly virulent strains. PMID:11158088

  14. Characterisation of a novel integrative and conjugative element ICESsD9 carrying erm(B) and tet(O) resistance determinants in Streptococcus suis, and the distribution of ICESsD9-like elements in clinical isolates.

    PubMed

    Huang, Kaisong; Song, Yajing; Zhang, Qiang; Zhang, Anding; Jin, Meilin

    2016-12-01

    This study identified a novel integrative and conjugative element (ICESsD9) carrying erm(B) and tet(O) resistance determinants in Streptococcus suis D9 and determined its prevalence in clinical isolates. Comparative genome analysis was performed using Mauve and Artemis Comparison Tool visualisation programs. Inverse PCR was utilised to detect its circular intermediate. The transfer capacity of ICESsD9 was evaluated by mating assays using S. suis A7 and Enterococcus faecalis JH2-2 as recipients. A genome walking approach was employed to analyse the characteristics of integration sites in transconjugants. A total of 118 clinical S. suis isolates were tested by PCR mapping assays to detect ICESsD9-like elements. MLST was performed on isolates containing ICESsD9 variants to determine their clonal relatedness. This 55 683-bp element can actively excise from the chromosome. Additionally, it was capable of transferring both into S. suis and E. faecalis with frequencies of 1.2×10(-4) and 5.8×10(-6) per donor, respectively. When investigating integration site features, it was found that ICESsD9 can enter S. suis and E. faecalis chromosomes by different sites, generating 15-bp and 3-bp direct repeat sequences, respectively. Twelve isolates mainly belonging to sequence types ST1, ST7 and ST28 were confirmed to harbour ICESsD9-like elements. In conclusion, this study provides the first description of an ICE in S. suis that is capable of transferring both into S. suis and E. faecalis. The presence of different ICESsD9 variants in clinical isolates suggests already wide dissemination of this family element in S. suis in China. Copyright © 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

  15. The analysis of the intramacrophagic virulome of Brucella suis deciphers the environment encountered by the pathogen inside the macrophage host cell

    PubMed Central

    Köhler, Stephan; Foulongne, Vincent; Ouahrani-Bettache, Safia; Bourg, Gisèle; Teyssier, Jacques; Ramuz, Michel; Liautard, Jean-Pierre

    2002-01-01

    The pathogen Brucella suis resides and multiplies within a phagocytic vacuole of its host cell, the macrophage. The resulting complex relationship has been investigated by the analysis of the set of genes required for virulence, which we call intramacrophagic virulome. Ten thousand two hundred and seventy-two miniTn5 mutants of B. suis constitutively expressing gfp were screened by fluorescence microscopy for lack of intracellular multiplication in human macrophages. One hundred thirty-one such mutants affected in 59 different genes could be isolated, and a function was ascribed to 53 of them. We identified genes involved in (i) global adaptation to the intracellular environment, (ii) amino acid, and (iii) nucleotide synthesis, (iv) sugar metabolism, (v) oxidoreduction, (vi) nitrogen metabolism, (vii) regulation, (viii) disulphide bond formation, and (ix) lipopolysaccharide biosynthesis. Results led to the conclusion that the replicative compartment of B. suis is poor in nutrients and characterized by low oxygen tension, and that nitrate may be used for anaerobic respiration. Intramacrophagic virulome analysis hence allowed the description of the nature of the replicative vacuole of the pathogen in the macrophage and extended our understanding of the niche in which B. suis resides. We propose calling this specific compartment “brucellosome.” PMID:12438693

  16. Structural genomics studies of human caries pathogen Streptococcus mutans.

    PubMed

    Li, Lanfen; Nan, Jie; Li, Dan; Brostromer, Erik; Wang, Zixi; Liu, Cong; Hou, Qiaoming; Fan, Xuexin; Ye, Zhaoyang; Su, Xiao-Dong

    2014-09-01

    Gram-positive bacterium Streptococcus mutans is the primary causative agent of human dental caries. To better understand this pathogen at the atomic structure level and to establish potential drug and vaccine targets, we have carried out structural genomics research since 2005. To achieve the goal, we have developed various in-house automation systems including novel high-throughput crystallization equipment and methods, based on which a large-scale, high-efficiency and low-cost platform has been establish in our laboratory. From a total of 1,963 annotated open reading frames, 1,391 non-membrane targets were selected prioritized by protein sequence similarities to unknown structures, and clustered by restriction sites to allow for cost-effective high-throughput conventional cloning. Selected proteins were over-expressed in different strains of Escherichia coli. Clones expressed soluble proteins were selected, expanded, and expressed proteins were purified and subjected to crystallization trials. Finally, protein crystals were subjected to X-ray analysis and structures were determined by crystallographic methods. Using the previously established procedures, we have so far obtained more than 200 kinds of protein crystals and 100 kinds of crystal structures involved in different biological pathways. In this paper we demonstrate and review a possibility of performing structural genomics studies at moderate laboratory scale. Furthermore, the techniques and methods developed in our study can be widely applied to conventional structural biology research practice.

  17. Genome of the Opportunistic Pathogen Streptococcus sanguinis▿ †

    PubMed Central

    Xu, Ping; Alves, Joao M.; Kitten, Todd; Brown, Arunsri; Chen, Zhenming; Ozaki, Luiz S.; Manque, Patricio; Ge, Xiuchun; Serrano, Myrna G.; Puiu, Daniela; Hendricks, Stephanie; Wang, Yingping; Chaplin, Michael D.; Akan, Doruk; Paik, Sehmi; Peterson, Darrell L.; Macrina, Francis L.; Buck, Gregory A.

    2007-01-01

    The genome of Streptococcus sanguinis is a circular DNA molecule consisting of 2,388,435 bp and is 177 to 590 kb larger than the other 21 streptococcal genomes that have been sequenced. The G+C content of the S. sanguinis genome is 43.4%, which is considerably higher than the G+C contents of other streptococci. The genome encodes 2,274 predicted proteins, 61 tRNAs, and four rRNA operons. A 70-kb region encoding pathways for vitamin B12 biosynthesis and degradation of ethanolamine and propanediol was apparently acquired by horizontal gene transfer. The gene complement suggests new hypotheses for the pathogenesis and virulence of S. sanguinis and differs from the gene complements of other pathogenic and nonpathogenic streptococci. In particular, S. sanguinis possesses a remarkable abundance of putative surface proteins, which may permit it to be a primary colonizer of the oral cavity and agent of streptococcal endocarditis and infection in neutropenic patients. PMID:17277061

  18. Pathobiology of Mycoplasma suis.

    PubMed

    Hoelzle, Ludwig E; Zeder, Michael; Felder, Kathrin M; Hoelzle, Katharina

    2014-10-01

    Mycoplasma suis is an uncultivable bacterium lacking a cell wall that attaches to and may invade the red blood cells of pigs. M. suis infections occur worldwide and cause the pig industry serious economic losses due to the disease known as infectious anaemia of pigs or, historically, porcine eperythrozoonosis. Infectious anaemia of pigs is characterised predominantly by acute haemolytic or chronic anaemia, along with non-specific manifestations, such as growth retardation in feeder pigs and poor reproductive performance in sows. The fastidious nature of M. suis, as well as the lack of an in vitro cultivation system, has hampered the understanding of the biology and pathogenicity of this organism. Pathogenetic mechanisms of M. suis include direct destruction of red blood cells by adhesion, invasion, nutrient scavenging, immune-mediated lysis and eryptosis, as well as endothelial targeting. Recently published genome sequences, in combination with proteome analyses, have generated new insights into the pathogenicity of M. suis. The present review combines these data with the knowledge provided by experimental M. suis infections.

  19. Antioxidant Activity and Antibacterial Effects on Clinical Isolated Streptococcus suis and Staphylococcus intermedius of Extracts from Several Parts of Cladogynos orientalis and Their Phytochemical Screenings.

    PubMed

    Sithisarn, Pongtip; Rojsanga, Piyanuch; Sithisarn, Patchima; Kongkiatpaiboon, Sumet

    2015-01-01

    The in vitro antioxidant and antibacterial assays against clinically isolated Streptococcus suis and Staphylococcus intermedius of the extracts prepared by decoction and ethanolic reflux of different parts of Chettaphangki (Cladogynos orientalis Zipp. ex Span), including the leaves, roots, and stems, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay and disc diffusion method were conducted. Quantitative analysis of total phenolic and total flavonoid contents in the extracts using spectrophotometric methods was also performed. Finally, phytochemical screening by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) was conducted. Leaf ethanolic reflux extract (100 g) contained the highest total phenolic and total flavonoid contents of 7.21 ± 0.28 μg gallic acid equivalent (GAE) and 11.51 ± 2.02 μg rutin equivalent (RE), respectively. Chettaphangki extracts promoted low antioxidant activity with EC50 values in the range of 0.27-0.48 mg/mL. Extracts and fractions from the roots and stems of this plant promoted low to intermediate antibacterial activity against S. intermedius with the inhibition zones between 7 and 14 mm. The chromatographic data suggested that the leaf extracts of C. orientalis contained rutin while the root and stem extracts contained scopoletin and chettaphanin I. Rutin promoted strong antioxidant activity while chettaphanin I showed low antibacterial activity against Staphylococcus intermedius.

  20. Factor H specifically capture novel Factor H-binding proteins of Streptococcus suis and contribute to the virulence of the bacteria.

    PubMed

    Li, Quan; Ma, Caifeng; Fu, Yang; He, Yanan; Yu, Yanfei; Du, Dechao; Yao, Huochun; Lu, Chengping; Zhang, Wei

    2017-03-01

    Factor H (FH), a regulatory protein of the complement system, can bind specifically to factor H-binding proteins (FHBPs) of Streptococcus suis serotype 2 (SS2), which contribute to evasion of host innate immune defenses. In the present study, we aimed to identify novel FHBPs and characterize the biological functions of FH in SS2 pathogenesis. Here, a method that combined proteomics and Far-western blotting was developed to identify the surface FHBPs of SS2. With this method, fourteen potential novel FHBPs were identified among SS2 surface proteins. We selected eight newly identified proteins and further confirmed their binding activity to FH. The binding of SS2 to immobilized FH decreased dramatically after pre-incubation with anti-FHBPs polyclonal antibodies. We showed for the first time that SS2 also interact specifically with mouse FH. Furthermore, we found that FH play an important role in adherence and invasion of SS2 to HEp-2 cells. Additionally, using a mouse model of intraperitoneal challenge, we confirmed that SS2 pre-incubated with FH enhanced bacteremia and brain invasion, compared with SS2 not pretreated with FH. Taken together, this study provides a useful method to characterize the host-bacteria interactions. These results first indicated that binding of FH to the cell surface improved the adherence and invasion of SS2 to HEp-2 cells, promoting SS2 to resist killing and leading to enhance virulence. Copyright © 2016 Elsevier GmbH. All rights reserved.

  1. A newly anti-Streptococcus suis bacteriocin producing strain from unweaned piglets fecal matter: isolation, preliminary identification, and optimization of medium composition for enhanced bacteriocin production.

    PubMed

    Zhang, Xiangmei; Chang, Xiaoyuan; Liu, Guorong; Wu, Pengpeng; Li, Pinglan

    2012-01-01

    A newly isolated anti-Streptococcus suis bacteriocin-producing strain LPL1-5 was obtained from healthy unweaned piglets' fecal matter, and was designated as Lactobacillus pentosus LPL1-5 based on morphology, biochemical properties, and 16S rDNA sequencing analysis. The medium composition for enhanced bacteriocin production by L. pentosus LPL1-5 was optimized by statistical methodology. Yeast extract, K(2)HPO(4)·3H(2)O, and MnSO(4)·H(2)O were identified as significant components influencing pentocin LPL1-5 production using the Plackett-Burman method. Response surface methodology was applied for further optimization. The concentrations of medium components for enhanced pentocin LPL1-5 production were as follows (g/L): lactose 20.00, tryptone 10.00, beef extract 10.00, yeast extract 14.00, MnSO(4)·H(2)O 0.84, K(2)HPO(4)·3H(2)O 4.92, triammonium citrate 2.00, Na-acetate 5.00, MgSO(4)·7H(2)O 0.58, Tween 80 1.00. Under the optimized condition, a value of 3154.65 ± 27.93 IU/mL bacteriocin activity was achieved, which was 4.2-fold that of the original medium.

  2. Expression, purification, crystallization and structure determination of the N terminal domain of Fhb, a factor H binding protein from Streptococcus suis

    SciTech Connect

    Zhang, Chunmao; Yu, You; Yang, Maojun; Jiang, Yongqiang

    2015-10-23

    Fhb is a surface virulence protein from Streptococcus suis, which could aid bacterial evasion of host innate immune defense by recruiting complement regulator factor H to inactivate C3b deposited on bacterial surface in blood. Here we successfully expressed and purified the N terminal domain of Fhb (N-Fhb) and obtained crystals of the N-Fhb by sitting-drop vapor diffusion method with a resolution of 1.50 Å. The crystals belong to space group C2 with unit cell parameters a = 127.1 Å, b = 77.3 Å, c = 131.6 Å, α = 90°, β = 115.9°, γ = 90°. The structure of N-Fhb was determined by SAD method and the core structure of N-Fhb is a β sandwich. We speculated that binding of Fhb to human factor H may be mainly mediated by surface amino acids with negative charges. - Highlights: • We expressed N-Fhb as the soluble protein in Escherichia coli. • Crystals of N-Fhb were grown by sitting drop vapor diffusion method. • Crystals of N-Fhb could diffracted to 1.5 Å. • The core structure of N-Fhb was a β sandwich. • A part of the surface of N-Fhb was rich with negative charges.

  3. Tetracycline Selective Pressure and Homologous Recombination Shape the Evolution of Chlamydia suis: A Recently Identified Zoonotic Pathogen.

    PubMed

    Joseph, Sandeep J; Marti, Hanna; Didelot, Xavier; Read, Timothy D; Dean, Deborah

    2016-09-02

    Species closely related to the human pathogen Chlamydia trachomatis (Ct) have recently been found to cause zoonotic infections, posing a public health threat especially in the case of tetracycline resistant Chlamydia suis (Cs) strains. These strains acquired a tet(C)-containing cassette via horizontal gene transfer (HGT). Genomes of 11 Cs strains from various tissues were sequenced to reconstruct evolutionary pathway(s) for tet(C) HGT. Cs had the highest recombination rate of Chlamydia species studied to date. Admixture occurred among Cs strains and with Chlamydia muridarum but not with Ct Although in vitro tet(C) cassette exchange with Ct has been documented, in vivo evidence may require examining human samples from Ct and Cs co-infected sites. Molecular-clock dating indicated that ancestral clades of resistant Cs strains predated the 1947 discovery of tetracycline, which was subsequently used in animal feed. The cassette likely spread throughout Cs strains by homologous recombination after acquisition from an external source, and our analysis suggests Betaproteobacteria as the origin. Selective pressure from tetracycline may be responsible for recent bottlenecks in Cs populations. Since tetracycline is an important antibiotic for treating Ct, zoonotic infections at mutual sites of infection indicate the possibility for cassette transfer and major public health repercussions. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  4. Tetracycline Selective Pressure and Homologous Recombination Shape the Evolution of Chlamydia suis: A Recently Identified Zoonotic Pathogen

    PubMed Central

    Joseph, Sandeep J.; Marti, Hanna; Didelot, Xavier; Read, Timothy D.; Dean, Deborah

    2016-01-01

    Species closely related to the human pathogen Chlamydia trachomatis (Ct) have recently been found to cause zoonotic infections, posing a public health threat especially in the case of tetracycline resistant Chlamydia suis (Cs) strains. These strains acquired a tet(C)-containing cassette via horizontal gene transfer (HGT). Genomes of 11 Cs strains from various tissues were sequenced to reconstruct evolutionary pathway(s) for tet(C) HGT. Cs had the highest recombination rate of Chlamydia species studied to date. Admixture occurred among Cs strains and with Chlamydia muridarum but not with Ct. Although in vitro tet(C) cassette exchange with Ct has been documented, in vivo evidence may require examining human samples from Ct and Cs co-infected sites. Molecular-clock dating indicated that ancestral clades of resistant Cs strains predated the 1947 discovery of tetracycline, which was subsequently used in animal feed. The cassette likely spread throughout Cs strains by homologous recombination after acquisition from an external source, and our analysis suggests Betaproteobacteria as the origin. Selective pressure from tetracycline may be responsible for recent bottlenecks in Cs populations. Since tetracycline is an important antibiotic for treating Ct, zoonotic infections at mutual sites of infection indicate the possibility for cassette transfer and major public health repercussions. PMID:27576537

  5. Thalamic abscess caused by a rare pathogen: streptococcus constellatus

    PubMed Central

    Şenol, Özgür; Süslü, Hikmet Turan; Tatarlı, Necati; Tiryaki, Mehmet; Güçlü, Bülent

    2016-01-01

    Streptococcus constellatus is a microorganism that lives commensally in the oropharyngeal region, urogenital region, and intestinal tract. However, it can cause infection in patients with certain predisposing factors. Rarely, this microorganism can cause a brain abscess. Thalamic localization of brain abscesses is much rarer than abscesses in other locations of the brain. Brain abscess caused by streptococcus constellatus are very rarely been reported in the literature. We present a rare case of a left-sided thalamic abscess caused by streptococcus constellatus in a 25-year-old male patient who was injured by shrapnel pieces in the head and who was malnourished. The patient was successfully treated by stereotactic aspiration and antibiotherapy. PMID:27800109

  6. Mycoplasma suis infection results endothelial cell damage and activation: new insight into the cell tropism and pathogenicity of hemotrophic mycoplasma.

    PubMed

    Sokoli, Albina; Groebel, Katrin; Hoelzle, Katharina; Amselgruber, Werner M; Mateos, José M; Schneider, Mårten K J; Ziegler, Urs; Felder, Kathrin M; Hoelzle, Ludwig E

    2013-02-11

    Hemotrophic mycoplasmas (HM) are highly specialized red blood cell parasites that cause infectious anemia in a variety of mammals, including humans. To date, no in vitro cultivation systems for HM have been available, resulting in relatively little information about the pathogenesis of HM infection. In pigs, Mycoplasma suis-induced infectious anemia is associated with hemorrhagic diathesis, and coagulation dysfunction. However, intravasal coagulation and subsequent consumption coagulopathy can only partly explain the sequence of events leading to hemorrhagic diathesis manifesting as cyanosis, petechial bleeding, and ecchymosis, and to disseminated coagulation. The involvement of endothelial activation and damage in M. suis-associated pathogenesis was investigated using light and electron microscopy, immunohistochemistry, and cell sorting. M. suis interacted directly with endothelial cells in vitro and in vivo. Endothelial activation, widespread endothelial damage, and adherence of red blood cells to the endothelium were evident in M. suis-infected pigs. These alterations of the endothelium were accompanied by hemorrhage, intravascular coagulation, vascular occlusion, and massive morphological changes within the parenchyma. M. suis biofilm-like microcolonies formed on the surface of endothelial cells, and may represent a putative persistence mechanism of M. suis. In vitro analysis demonstrated that M. suis interacted with the endothelial cytoskeletal protein actin, and induced actin condensation and activation of endothelial cells, as determined by the up-regulation of ICAM, PECAM, E-selectin, and P-selectin. These findings demonstrate an additional cell tropism of HM for endothelial cells and suggest that M. suis interferes with the protective function of the endothelium, resulting in hemorrhagic diathesis.

  7. Mycoplasma suis infection results endothelial cell damage and activation: new insight into the cell tropism and pathogenicity of hemotrophic mycoplasma

    PubMed Central

    2013-01-01

    Hemotrophic mycoplasmas (HM) are highly specialized red blood cell parasites that cause infectious anemia in a variety of mammals, including humans. To date, no in vitro cultivation systems for HM have been available, resulting in relatively little information about the pathogenesis of HM infection. In pigs, Mycoplasma suis-induced infectious anemia is associated with hemorrhagic diathesis, and coagulation dysfunction. However, intravasal coagulation and subsequent consumption coagulopathy can only partly explain the sequence of events leading to hemorrhagic diathesis manifesting as cyanosis, petechial bleeding, and ecchymosis, and to disseminated coagulation. The involvement of endothelial activation and damage in M. suis-associated pathogenesis was investigated using light and electron microscopy, immunohistochemistry, and cell sorting. M. suis interacted directly with endothelial cells in vitro and in vivo. Endothelial activation, widespread endothelial damage, and adherence of red blood cells to the endothelium were evident in M. suis-infected pigs. These alterations of the endothelium were accompanied by hemorrhage, intravascular coagulation, vascular occlusion, and massive morphological changes within the parenchyma. M. suis biofilm-like microcolonies formed on the surface of endothelial cells, and may represent a putative persistence mechanism of M. suis. In vitro analysis demonstrated that M. suis interacted with the endothelial cytoskeletal protein actin, and induced actin condensation and activation of endothelial cells, as determined by the up-regulation of ICAM, PECAM, E-selectin, and P-selectin. These findings demonstrate an additional cell tropism of HM for endothelial cells and suggest that M. suis interferes with the protective function of the endothelium, resulting in hemorrhagic diathesis. PMID:23398879

  8. Identification of the Novel Lincosamide Resistance Gene lnu(E) Truncated by ISEnfa5-cfr-ISEnfa5 Insertion in Streptococcus suis: De Novo Synthesis and Confirmation of Functional Activity in Staphylococcus aureus

    PubMed Central

    Zhao, Qin; Wendlandt, Sarah; Li, Hui; Li, Jun; Wu, Congming; Shen, Jianzhong

    2014-01-01

    The novel lincosamide resistance gene lnu(E), truncated by insertion of an ISEnfa5-cfr-ISEnfa5 segment, was identified in Streptococcus suis. The gene lnu(E) encodes a 173-amino-acid protein with ≤69.4% identity to other lincosamide nucleotidyltransferases. The lnu(E) gene and its promoter region were de novo synthesized, and Staphylococcus aureus RN4220 carrying a shuttle vector with the cloned lnu(E) gene showed a 16-fold increase in the lincomycin MIC. Mass spectrometry experiments demonstrated that Lnu(E) catalyzed the nucleotidylation of lincomycin. PMID:24366733

  9. Streptococcus parasanguinis: new pathogen associated with asymptomatic mastitis in sheep.

    PubMed Central

    Fernández-Garayzábal, J. F.; Fernández, E.; Las Heras, A.; Pascual, C.; Collins, M. D.; Domínguez, L.

    1998-01-01

    We describe two unusual cases in sheep of subclinical mastitis caused by Streptococcus parasanguinis. This bacterium has been associated with the development of experimental endocarditis; its presence at relatively high concentrations in apparently healthy sheep milk may pose a health risk in persons with predisposing heart lesions. PMID:9866743

  10. RegA Plays a Key Role in Oxygen-Dependent Establishment of Persistence and in Isocitrate Lyase Activity, a Critical Determinant of In vivo Brucella suis Pathogenicity

    PubMed Central

    Abdou, Elias; Jiménez de Bagüés, María P.; Martínez-Abadía, Ignacio; Ouahrani-Bettache, Safia; Pantesco, Véronique; Occhialini, Alessandra; Al Dahouk, Sascha; Köhler, Stephan; Jubier-Maurin, Véronique

    2017-01-01

    For aerobic human pathogens, adaptation to hypoxia is a critical factor for the establishment of persistent infections, as oxygen availability is low inside the host. The two-component system RegB/A of Brucella suis plays a central role in the control of respiratory systems adapted to oxygen deficiency, and in persistence in vivo. Using an original “in vitro model of persistence” consisting in gradual oxygen depletion, we compared transcriptomes and proteomes of wild-type and ΔregA strains to identify the RegA-regulon potentially involved in the set-up of persistence. Consecutive to oxygen consumption resulting in growth arrest, 12% of the genes in B. suis were potentially controlled directly or indirectly by RegA, among which numerous transcriptional regulators were up-regulated. In contrast, genes or proteins involved in envelope biogenesis and in cellular division were repressed, suggesting a possible role for RegA in the set-up of a non-proliferative persistence state. Importantly, the greatest number of the RegA-repressed genes and proteins, including aceA encoding the functional IsoCitrate Lyase (ICL), were involved in energy production. A potential consequence of this RegA impact may be the slowing-down of the central metabolism as B. suis progressively enters into persistence. Moreover, ICL is an essential determinant of pathogenesis and long-term interactions with the host, as demonstrated by the strict dependence of B. suis on ICL activity for multiplication and persistence during in vivo infection. RegA regulates gene or protein expression of all functional groups, which is why RegA is a key regulator of B. suis in adaptation to oxygen depletion. This function may contribute to the constraint of bacterial growth, typical of chronic infection. Oxygen-dependent activation of two-component systems that control persistence regulons, shared by several aerobic human pathogens, has not been studied in Brucella sp. before. This work therefore contributes

  11. RegA Plays a Key Role in Oxygen-Dependent Establishment of Persistence and in Isocitrate Lyase Activity, a Critical Determinant of In vivo Brucella suis Pathogenicity.

    PubMed

    Abdou, Elias; Jiménez de Bagüés, María P; Martínez-Abadía, Ignacio; Ouahrani-Bettache, Safia; Pantesco, Véronique; Occhialini, Alessandra; Al Dahouk, Sascha; Köhler, Stephan; Jubier-Maurin, Véronique

    2017-01-01

    For aerobic human pathogens, adaptation to hypoxia is a critical factor for the establishment of persistent infections, as oxygen availability is low inside the host. The two-component system RegB/A of Brucella suis plays a central role in the control of respiratory systems adapted to oxygen deficiency, and in persistence in vivo. Using an original "in vitro model of persistence" consisting in gradual oxygen depletion, we compared transcriptomes and proteomes of wild-type and ΔregA strains to identify the RegA-regulon potentially involved in the set-up of persistence. Consecutive to oxygen consumption resulting in growth arrest, 12% of the genes in B. suis were potentially controlled directly or indirectly by RegA, among which numerous transcriptional regulators were up-regulated. In contrast, genes or proteins involved in envelope biogenesis and in cellular division were repressed, suggesting a possible role for RegA in the set-up of a non-proliferative persistence state. Importantly, the greatest number of the RegA-repressed genes and proteins, including aceA encoding the functional IsoCitrate Lyase (ICL), were involved in energy production. A potential consequence of this RegA impact may be the slowing-down of the central metabolism as B. suis progressively enters into persistence. Moreover, ICL is an essential determinant of pathogenesis and long-term interactions with the host, as demonstrated by the strict dependence of B. suis on ICL activity for multiplication and persistence during in vivo infection. RegA regulates gene or protein expression of all functional groups, which is why RegA is a key regulator of B. suis in adaptation to oxygen depletion. This function may contribute to the constraint of bacterial growth, typical of chronic infection. Oxygen-dependent activation of two-component systems that control persistence regulons, shared by several aerobic human pathogens, has not been studied in Brucella sp. before. This work therefore contributes

  12. Draft Genome Sequence of Streptococcus anginosus BVI, a New Vaginal Pathogen Candidate

    PubMed Central

    Tobar-Tosse, Fabian; Guillermo-Ortega, Jose; Wibberg, Daniel; Tauch, Andreas

    2016-01-01

    Streptococcus anginosus is a pathogen implicated in urogenital and gastroinstestinal tract infections. Here, we report the draft genome sequence of S. anginosus BVI, isolated from a bacterial vaginosis patient attending a prenatal care unit in Cali, Colombia. The genome sequence of BVI consists of 2,014,025 bp, encoding 2,008 predicted proteins. PMID:27979955

  13. Streptococcus iniae, a Human and Animal Pathogen: Specific Identification by the Chaperonin 60 Gene Identification Method

    PubMed Central

    Goh, Swee Han; Driedger, David; Gillett, Sandra; Low, Donald E.; Hemmingsen, Sean M.; Amos, Mayben; Chan, David; Lovgren, Marguerite; Willey, Barbara M.; Shaw, Carol; Smith, John A.

    1998-01-01

    It was recently reported that Streptococcus iniae, a bacterial pathogen of aquatic animals, can cause serious disease in humans. Using the chaperonin 60 (Cpn60) gene identification method with reverse checkerboard hybridization and chemiluminescent detection, we identified correctly each of 12 S. iniae samples among 34 aerobic gram-positive isolates from animal and clinical human sources. PMID:9650992

  14. The thioredoxin system in the dental caries pathogen Streptococcus mutans and the food-industry bacterium Streptococcus thermophilus.

    PubMed

    Marco, Salvatore; Rullo, Rosario; Albino, Antonella; Masullo, Mariorosario; De Vendittis, Emmanuele; Amato, Massimo

    2013-11-01

    The Streptococcus genus includes the pathogenic species Streptococcus mutans, the main responsible of dental caries, and the safe microorganism Streptococcus thermophilus, used for the manufacture of dairy products. These facultative anaerobes control the levels of reactive oxygen species (ROS) and indeed, both S. mutans and S. thermophilus possess a cambialistic superoxide dismutase, the key enzyme for a preventive action against ROS. To evaluate the properties of a crucial mechanism for repairing ROS damages, the molecular and functional characterization of the thioredoxin system in these streptococci was investigated. The putative genes encoding its protein components in S. mutans and S. thermophilus were analysed and the corresponding recombinant proteins were purified. A single thioredoxin reductase was obtained from either S. mutans (SmTrxB) or S. thermophilus (StTrxB1), whereas two thioredoxins were prepared from either S. mutans (SmTrxA and SmTrxH1) or S. thermophilus (StTrxA1 and StTrxA2). Both SmTrxB and StTrxB1 reduced the synthetic substrate DTNB in the presence of NADPH, whereas only SmTrxA and StTrxA1 accelerated the insulin reduction in the presence of DTT. To reconstitute an in vitro streptococcal thioredoxin system, the combined activity of the thioredoxin components was tested through the insulin precipitation in the absence of DTT. The assay functions with a combination of SmTrxB or StTrxB1 with either SmTrxA or StTrxA1. These results suggest that the streptococcal members of the thioredoxin system display a direct functional interaction between them and that these protein components are interchangeable within the Streptococcus genus. In conclusion, our data prove the existence of a functioning thioredoxin system even in these microaerophiles.

  15. Streptococcus iniae and Streptococcus agalactiae

    USDA-ARS?s Scientific Manuscript database

    Streptococcus iniae and S. agalactiae are economically important Gram positive bacterial pathogens of cultured and wild fish with a worldwide distribution. Both bacteria are potential zoonotic pathogens and have been associated most often with infections in immunocompromised people. Streptococcus in...

  16. Disease Manifestations and Pathogenic Mechanisms of Group A Streptococcus

    PubMed Central

    Barnett, Timothy C.; McArthur, Jason D.; Cole, Jason N.; Gillen, Christine M.; Henningham, Anna; Sriprakash, K. S.; Sanderson-Smith, Martina L.; Nizet, Victor

    2014-01-01

    SUMMARY Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority. PMID:24696436

  17. The usefulness of biotyping in the determination of selected pathogenicity determinants in Streptococcus mutans

    PubMed Central

    2014-01-01

    Background Streptococcus mutans is known to be a primary etiological factor of dental caries, a widespread and growing disease in Polish children. Recognition of novel features determining the pathogenicity of this pathogen may contribute to understanding the mechanisms of bacterial infections. The goal of the study was to determine the activity of prephenate dehydrogenase (PHD) and to illuminate the role of the enzyme in S. mutans pathogenicity. The strains were biotyped based on STREPTOtest 24 biochemical identification tests and the usefulness of biotyping in the determination of S. mutans pathogenicity determinants was examined. Results Out of ninety strains isolated from children with deciduous teeth fifty three were classified as S. mutans species. PDH activity was higher (21.69 U/mg on average) in the experimental group compared to the control group (5.74 U/mg on average) (P <0.001). Moreover, it was demonstrated that biotype I, established basing on the biochemical characterization of the strain, was predominant (58.5%) in oral cavity streptococcosis. Its dominance was determined by higher PDH activity compared to biotypes II and III (P = 0.0019). Conclusions The usefulness of biotyping in the determination of Streptococcus mutans pathogenicity determinants was demonstrated. The obtained results allow for better differentiation of S. mutans species and thus may contribute to recognition of pathogenic bacteria transmission mechanisms and facilitate treatment. PMID:25096795

  18. Genome characterization and population genetic structure of the zoonotic pathogen, Streptococcus canis

    PubMed Central

    2012-01-01

    Background Streptococcus canis is an important opportunistic pathogen of dogs and cats that can also infect a wide range of additional mammals including cows where it can cause mastitis. It is also an emerging human pathogen. Results Here we provide characterization of the first genome sequence for this species, strain FSL S3-227 (milk isolate from a cow with an intra-mammary infection). A diverse array of putative virulence factors was encoded by the S. canis FSL S3-227 genome. Approximately 75% of these gene sequences were homologous to known Streptococcal virulence factors involved in invasion, evasion, and colonization. Present in the genome are multiple potentially mobile genetic elements (MGEs) [plasmid, phage, integrative conjugative element (ICE)] and comparison to other species provided convincing evidence for lateral gene transfer (LGT) between S. canis and two additional bovine mastitis causing pathogens (Streptococcus agalactiae, and Streptococcus dysgalactiae subsp. dysgalactiae), with this transfer possibly contributing to host adaptation. Population structure among isolates obtained from Europe and USA [bovine = 56, canine = 26, and feline = 1] was explored. Ribotyping of all isolates and multi locus sequence typing (MLST) of a subset of the isolates (n = 45) detected significant differentiation between bovine and canine isolates (Fisher exact test: P = 0.0000 [ribotypes], P = 0.0030 [sequence types]), suggesting possible host adaptation of some genotypes. Concurrently, the ancestral clonal complex (54% of isolates) occurred in many tissue types, all hosts, and all geographic locations suggesting the possibility of a wide and diverse niche. Conclusion This study provides evidence highlighting the importance of LGT in the evolution of the bacteria S. canis, specifically, its possible role in host adaptation and acquisition of virulence factors. Furthermore, recent LGT detected between S. canis and human bacteria (Streptococcus

  19. Syringa oblata Lindl. Aqueous Extract Is a Potential Biofilm Inhibitor in S. suis

    PubMed Central

    Bai, Jingwen; Yang, Yanbei; Wang, Shuai; Gao, Lingfei; Chen, Jianqing; Ren, Yongzhi; Ding, Wenya; Muhammad, Ishfaq; Li, Yanhua

    2017-01-01

    Streptococcus suis (S. suis) is a zoonotic pathogen that causes severe disease symptoms in pigs and humans. Syringa oblata Lindl. distributed in the middle latitudes of Eurasia and North America were proved as the most development potential of Chinese Medicine. In this study, biofilm formation by S. suis decreased after growth with 1/2 MIC, 1/4 MIC, or 1/8 MIC of Syringa oblata Lindl. aqueous extract and rutin. Scanning electron microscopy analysis revealed the potential effect of Syringa oblata Lindl. aqueous extract and rutin against biofilm formation by S. suis. Using iTRAQ technology, comparative proteomic analyses was performed at two conditions: 1/2 MIC of Syringa oblata Lindl. aqueous extract treated and non-treated cells. The results revealed the existence of 28 proteins of varying amounts. We found that the majority of the proteins were related to cell growth and metabolism. We also found that Syringa oblata Lindl. Aqueous extract affected the synthesis enzymes. In summary, Syringa oblata Lindl. aqueous extract might be used to inhibit the biofilm formation effectively by S. suis, and the active ingredients of the Syringa oblate Lindl. aqueous extract is rutin. The content of rutin is 9.9 ± 0.089 mg/g dry weight. PMID:28194111

  20. Syringa oblata Lindl. Aqueous Extract Is a Potential Biofilm Inhibitor in S. suis.

    PubMed

    Bai, Jingwen; Yang, Yanbei; Wang, Shuai; Gao, Lingfei; Chen, Jianqing; Ren, Yongzhi; Ding, Wenya; Muhammad, Ishfaq; Li, Yanhua

    2017-01-01

    Streptococcus suis (S. suis) is a zoonotic pathogen that causes severe disease symptoms in pigs and humans. Syringa oblata Lindl. distributed in the middle latitudes of Eurasia and North America were proved as the most development potential of Chinese Medicine. In this study, biofilm formation by S. suis decreased after growth with 1/2 MIC, 1/4 MIC, or 1/8 MIC of Syringa oblata Lindl. aqueous extract and rutin. Scanning electron microscopy analysis revealed the potential effect of Syringa oblata Lindl. aqueous extract and rutin against biofilm formation by S. suis. Using iTRAQ technology, comparative proteomic analyses was performed at two conditions: 1/2 MIC of Syringa oblata Lindl. aqueous extract treated and non-treated cells. The results revealed the existence of 28 proteins of varying amounts. We found that the majority of the proteins were related to cell growth and metabolism. We also found that Syringa oblata Lindl. Aqueous extract affected the synthesis enzymes. In summary, Syringa oblata Lindl. aqueous extract might be used to inhibit the biofilm formation effectively by S. suis, and the active ingredients of the Syringa oblate Lindl. aqueous extract is rutin. The content of rutin is 9.9 ± 0.089 mg/g dry weight.

  1. Evidence for niche adaptation in the genome of the bovine pathogen Streptococcus uberis

    PubMed Central

    Ward, Philip N; Holden, Matthew TG; Leigh, James A; Lennard, Nicola; Bignell, Alexandra; Barron, Andy; Clark, Louise; Quail, Michael A; Woodward, John; Barrell, Bart G; Egan, Sharon A; Field, Terence R; Maskell, Duncan; Kehoe, Michael; Dowson, Christopher G; Chanter, Neil; Whatmore, Adrian M; Bentley, Stephen D; Parkhill, Julian

    2009-01-01

    Background Streptococcus uberis, a Gram positive bacterial pathogen responsible for a significant proportion of bovine mastitis in commercial dairy herds, colonises multiple body sites of the cow including the gut, genital tract and mammary gland. Comparative analysis of the complete genome sequence of S. uberis strain 0140J was undertaken to help elucidate the biology of this effective bovine pathogen. Results The genome revealed 1,825 predicted coding sequences (CDSs) of which 62 were identified as pseudogenes or gene fragments. Comparisons with related pyogenic streptococci identified a conserved core (40%) of orthologous CDSs. Intriguingly, S. uberis 0140J displayed a lower number of mobile genetic elements when compared with other pyogenic streptococci, however bacteriophage-derived islands and a putative genomic island were identified. Comparative genomics analysis revealed most similarity to the genomes of Streptococcus agalactiae and Streptococcus equi subsp. zooepidemicus. In contrast, streptococcal orthologs were not identified for 11% of the CDSs, indicating either unique retention of ancestral sequence, or acquisition of sequence from alternative sources. Functions including transport, catabolism, regulation and CDSs encoding cell envelope proteins were over-represented in this unique gene set; a limited array of putative virulence CDSs were identified. Conclusion S. uberis utilises nutritional flexibility derived from a diversity of metabolic options to successfully occupy a discrete ecological niche. The features observed in S. uberis are strongly suggestive of an opportunistic pathogen adapted to challenging and changing environmental parameters. PMID:19175920

  2. Comparative genome analysis of two Streptococcus phocae subspecies provides novel insights into pathogenicity.

    PubMed

    Bethke, J; Avendaño-Herrera, R

    2017-02-01

    Streptococcus phocae is a beta-hemolytic, Gram-positive bacterium that was first isolated in Norway from clinical specimens of harbor seal (Phoca vitulina) affected by pneumonia or respiratory infection, and in 2005, this bacterium was identified from disease outbreaks at an Atlantic salmon farm. A recent comparative polyphasic study reclassified Streptococcus phocae as subsp. phocae and subsp. salmonis, and there are currently two S. phocae NCBI sequencing projects for the type strains ATCC 51973(T) and C-4(T). The present study compared these genome sequences to determine shared properties between the pathogenic mammalian and fish S. phocae subspecies. Both subspecies presented genomic islands, prophages, CRISPRs, and multiple gene activator and RofA regulator regions that could play key roles in the pathogenesis of streptococcal species. Likewise, proteins possibly influencing immune system evasion and virulence strategies were identified in both genomes, including Streptokinases, Streptolysin S, IgG endopeptidase, Fibronectin binding proteins, Daunorubicin, and Penicillin resistance proteins. Comparative differences in phage, non-phage, and genomic island sequences may form the genetic basis for the virulence, pathogenicity, and ability of S. phocae subsp. salmonis to infect and cause disease in Atlantic salmon, in contrast to S. phocae subsp. phocae. This comparative genomic study between two S. phocae subsp. provides novel insights into virulence factors and pathogenicity, offering important information that will facilitate the development of preventive and treatment measures against this pathogen. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Genomic Evidence for the Evolution of Streptococcus equi: Host Restriction, Increased Virulence, and Genetic Exchange with Human Pathogens

    PubMed Central

    Paillot, Romain; Steward, Karen F.; Webb, Katy; Ainslie, Fern; Jourdan, Thibaud; Bason, Nathalie C.; Holroyd, Nancy E.; Mungall, Karen; Quail, Michael A.; Sanders, Mandy; Simmonds, Mark; Willey, David; Brooks, Karen; Aanensen, David M.; Spratt, Brian G.; Jolley, Keith A.; Maiden, Martin C. J.; Kehoe, Michael; Chanter, Neil; Bentley, Stephen D.; Robinson, Carl; Maskell, Duncan J.; Parkhill, Julian; Waller, Andrew S.

    2009-01-01

    The continued evolution of bacterial pathogens has major implications for both human and animal disease, but the exchange of genetic material between host-restricted pathogens is rarely considered. Streptococcus equi subspecies equi (S. equi) is a host-restricted pathogen of horses that has evolved from the zoonotic pathogen Streptococcus equi subspecies zooepidemicus (S. zooepidemicus). These pathogens share approximately 80% genome sequence identity with the important human pathogen Streptococcus pyogenes. We sequenced and compared the genomes of S. equi 4047 and S. zooepidemicus H70 and screened S. equi and S. zooepidemicus strains from around the world to uncover evidence of the genetic events that have shaped the evolution of the S. equi genome and led to its emergence as a host-restricted pathogen. Our analysis provides evidence of functional loss due to mutation and deletion, coupled with pathogenic specialization through the acquisition of bacteriophage encoding a phospholipase A2 toxin, and four superantigens, and an integrative conjugative element carrying a novel iron acquisition system with similarity to the high pathogenicity island of Yersinia pestis. We also highlight that S. equi, S. zooepidemicus, and S. pyogenes share a common phage pool that enhances cross-species pathogen evolution. We conclude that the complex interplay of functional loss, pathogenic specialization, and genetic exchange between S. equi, S. zooepidemicus, and S. pyogenes continues to influence the evolution of these important streptococci. PMID:19325880

  4. Complete Genome Sequence and Immunoproteomic Analyses of the Bacterial Fish Pathogen Streptococcus parauberis▿†

    PubMed Central

    Nho, Seong Won; Hikima, Jun-ichi; Cha, In Seok; Park, Seong Bin; Jang, Ho Bin; del Castillo, Carmelo S.; Kondo, Hidehiro; Hirono, Ikuo; Aoki, Takashi; Jung, Tae Sung

    2011-01-01

    Although Streptococcus parauberis is known as a bacterial pathogen associated with bovine udder mastitis, it has recently become one of the major causative agents of olive flounder (Paralichthys olivaceus) streptococcosis in northeast Asia, causing massive mortality resulting in severe economic losses. S. parauberis contains two serotypes, and it is likely that capsular polysaccharide antigens serve to differentiate the serotypes. In the present study, the complete genome sequence of S. parauberis (serotype I) was determined using the GS-FLX system to investigate its phylogeny, virulence factors, and antigenic proteins. S. parauberis possesses a single chromosome of 2,143,887 bp containing 1,868 predicted coding sequences (CDSs), with an average GC content of 35.6%. Whole-genome dot plot analysis and phylogenetic analysis of a 60-kDa chaperonin-encoding gene and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-encoding gene showed that the strain was evolutionarily closely related to Streptococcus uberis. S. parauberis antigenic proteins were analyzed using an immunoproteomic technique. Twenty-one antigenic protein spots were identified in S. parauberis, by reaction with an antiserum obtained from S. parauberis-challenged olive flounder. This work provides the foundation needed to understand more clearly the relationship between pathogen and host and develops new approaches toward prophylactic and therapeutic strategies to deal with streptococcosis in fish. The work also provides a better understanding of the physiology and evolution of a significant representative of the Streptococcaceae. PMID:21531805

  5. Transcriptome Remodeling Contributes to Epidemic Disease Caused by the Human Pathogen Streptococcus pyogenes

    PubMed Central

    Beres, Stephen B.; Kachroo, Priyanka; Nasser, Waleed; Olsen, Randall J.; Zhu, Luchang; Flores, Anthony R.; de la Riva, Ivan; Paez-Mayorga, Jesus; Jimenez, Francisco E.; Cantu, Concepcion; Vuopio, Jaana; Jalava, Jari; Kristinsson, Karl G.; Gottfredsson, Magnus; Corander, Jukka; Fittipaldi, Nahuel; Di Luca, Maria Chiara; Petrelli, Dezemona; Vitali, Luca A.; Raiford, Annessa; Jenkins, Leslie

    2016-01-01

    ABSTRACT For over a century, a fundamental objective in infection biology research has been to understand the molecular processes contributing to the origin and perpetuation of epidemics. Divergent hypotheses have emerged concerning the extent to which environmental events or pathogen evolution dominates in these processes. Remarkably few studies bear on this important issue. Based on population pathogenomic analysis of 1,200 Streptococcus pyogenes type emm89 infection isolates, we report that a series of horizontal gene transfer events produced a new pathogenic genotype with increased ability to cause infection, leading to an epidemic wave of disease on at least two continents. In the aggregate, these and other genetic changes substantially remodeled the transcriptomes of the evolved progeny, causing extensive differential expression of virulence genes and altered pathogen-host interaction, including enhanced immune evasion. Our findings delineate the precise molecular genetic changes that occurred and enhance our understanding of the evolutionary processes that contribute to the emergence and persistence of epidemically successful pathogen clones. The data have significant implications for understanding bacterial epidemics and for translational research efforts to blunt their detrimental effects. PMID:27247229

  6. Molecular and genomic characterization of pathogenic traits of group A Streptococcus pyogenes

    PubMed Central

    HAMADA, Shigeyuki; KAWABATA, Shigetada; NAKAGAWA, Ichiro

    2015-01-01

    Group A streptococcus (GAS) or Streptococcus pyogenes causes various diseases ranging from self-limiting sore throat to deadly invasive diseases. The genome size of GAS is 1.85–1.9 Mb, and genomic rearrangement has been demonstrated. GAS possesses various surface-associated substances such as hyaluronic capsule, M proteins, and fibronectin/laminin/immunoglobulin-binding proteins. These are related to the virulence and play multifaceted and mutually reflected roles in the pathogenesis of GAS infections. Invasion of GAS into epithelial cells and deeper tissues provokes immune and non-immune defense or inflammatory responses including the recruitment of neutrophils, macrophages, and dendritic cells in hosts. GAS frequently evades host defense mechanisms by using its virulence factors. Extracellular products of GAS may perturb cellular and subcellular functions and degrade tissues enzymatically, which leads to the aggravation of local and/or systemic disorders in the host. In this review, we summarize some important cellular and extracellular substances that may affect pathogenic processes during GAS infections, and the host responses to these. PMID:26666305

  7. Essential Genes in the Core Genome of the Human Pathogen Streptococcus pyogenes

    PubMed Central

    Le Breton, Yoann; Belew, Ashton T.; Valdes, Kayla M.; Islam, Emrul; Curry, Patrick; Tettelin, Hervé; Shirtliff, Mark E.; El-Sayed, Najib M.; McIver, Kevin S.

    2015-01-01

    Streptococcus pyogenes (Group A Streptococcus, GAS) remains a major public health burden worldwide, infecting over 750 million people leading to over 500,000 deaths annually. GAS pathogenesis is complex, involving genetically distinct GAS strains and multiple infection sites. To overcome fastidious genetic manipulations and accelerate pathogenesis investigations in GAS, we developed a mariner-based system (Krmit) for en masse monitoring of complex mutant pools by transposon sequencing (Tn-seq). Highly saturated transposant libraries (Krmit insertions in ca. every 25 nucleotides) were generated in two distinct GAS clinical isolates, a serotype M1T1 invasive strain 5448 and a nephritogenic serotype M49 strain NZ131, and analyzed using a Bayesian statistical model to predict GAS essential genes, identifying sets of 227 and 241 of those genes in 5448 and NZ131, respectively. A large proportion of GAS essential genes corresponded to key cellular processes and metabolic pathways, and 177 were found conserved within the GAS core genome established from 20 available GAS genomes. Selected essential genes were validated using conditional-expression mutants. Finally, comparison to previous essentiality analyses in S. sanguinis and S. pneumoniae revealed significant overlaps, providing valuable insights for the development of new antimicrobials to treat infections by GAS and other pathogenic streptococci. PMID:25996237

  8. Role of Streptococcus intermedius DnaK chaperone system in stress tolerance and pathogenicity.

    PubMed

    Tomoyasu, Toshifumi; Tabata, Atsushi; Imaki, Hidenori; Tsuruno, Keigo; Miyazaki, Aya; Sonomoto, Kenji; Whiley, Robert Alan; Nagamune, Hideaki

    2012-01-01

    Streptococcus intermedius is a facultatively anaerobic, opportunistic pathogen that causes purulent infections and abscess formation. The DnaK chaperone system has been characterized in several pathogenic bacteria and seems to have important functions in stress resistance and pathogenicity. However, the role of DnaK in S. intermedius remains unclear. Therefore, we constructed a dnaK knockout mutant that exhibited slow growth, thermosensitivity, accumulation of GroEL in the cell, and reduced cytotoxicity to HepG2 cells. The level of secretion of a major pathogenic factor, intermedilysin, was not affected by dnaK mutation. We further examined the function and property of the S. intermedius DnaK chaperone system by using Escherichia coli ΔdnaK and ΔrpoH mutant strains. S. intermedius DnaK could not complement the thermosensitivity of E. coli ΔdnaK mutant. However, the intact S. intermedius DnaK chaperone system could complement the thermosensitivity and acid sensitivity of E. coli ΔdnaK mutant. The S. intermedius DnaK chaperone system could regulate the activity and stability of the heat shock transcription factor σ(32) in E. coli, although S. intermedius does not utilize σ(32) for heat shock transcription. The S. intermedius DnaK chaperone system was also able to efficiently eliminate the aggregated proteins from ΔrpoH mutant cells. Overall, our data showed that the S. intermedius DnaK chaperone system has important functions in quality control of cellular proteins but has less participation in the modulation of expression of pathogenic factors.

  9. The novel polysaccharide deacetylase homologue Pdi contributes to virulence of the aquatic pathogen Streptococcus iniae

    PubMed Central

    Milani, Carlo J. E.; Aziz, Ramy K.; Locke, Jeffrey B.; Dahesh, Samira; Nizet, Victor; Buchanan, John T.

    2010-01-01

    The aquatic zoonotic pathogen Streptococcus iniae represents a threat to the worldwide aquaculture industry and poses a risk to humans who handle raw fish. Because little is known about the mechanisms of S. iniae pathogenesis or virulence factors, we established a high-throughput system combining whole-genome pyrosequencing and transposon mutagenesis that allowed us to identify virulence proteins, including Pdi, the polysaccharide deacetylase of S. iniae, that we describe here. Using bioinformatics tools, we identified a highly conserved signature motif in Pdi that is also conserved in the peptidoglycan deacetylase PgdA protein family. A Δpdi mutant was attenuated for virulence in the hybrid striped bass model and for survival in whole fish blood. Moreover, Pdi was found to promote bacterial resistance to lysozyme killing and the ability to adhere to and invade epithelial cells. On the other hand, there was no difference in the autolytic potential, resistance to oxidative killing or resistance to cationic antimicrobial peptides between S. iniae wild-type and Δpdi. In conclusion, we have demonstrated that pdi is involved in S. iniae adherence and invasion, lysozyme resistance and survival in fish blood, and have shown that pdi plays a role in the pathogenesis of S. iniae. Identification of Pdi and other S. iniae virulence proteins is a necessary initial step towards the development of appropriate preventive and therapeutic measures against diseases and economic losses caused by this pathogen. PMID:19762441

  10. The Human Pathogen Streptococcus pyogenes Releases Lipoproteins as Lipoprotein-rich Membrane Vesicles.

    PubMed

    Biagini, Massimiliano; Garibaldi, Manuela; Aprea, Susanna; Pezzicoli, Alfredo; Doro, Francesco; Becherelli, Marco; Taddei, Anna Rita; Tani, Chiara; Tavarini, Simona; Mora, Marirosa; Teti, Giuseppe; D'Oro, Ugo; Nuti, Sandra; Soriani, Marco; Margarit, Immaculada; Rappuoli, Rino; Grandi, Guido; Norais, Nathalie

    2015-08-01

    Bacterial lipoproteins are attractive vaccine candidates because they represent a major class of cell surface-exposed proteins in many bacteria and are considered as potential pathogen-associated molecular patterns sensed by Toll-like receptors with built-in adjuvanticity. Although Gram-negative lipoproteins have been extensively characterized, little is known about Gram-positive lipoproteins. We isolated from Streptococcus pyogenes a large amount of lipoproteins organized in vesicles. These vesicles were obtained by weakening the bacterial cell wall with a sublethal concentration of penicillin. Lipid and proteomic analysis of the vesicles revealed that they were enriched in phosphatidylglycerol and almost exclusively composed of lipoproteins. In association with lipoproteins, a few hypothetical proteins, penicillin-binding proteins, and several members of the ExPortal, a membrane microdomain responsible for the maturation of secreted proteins, were identified. The typical lipidic moiety was apparently not necessary for lipoprotein insertion in the vesicle bilayer because they were also recovered from the isogenic diacylglyceryl transferase deletion mutant. The vesicles were not able to activate specific Toll-like receptor 2, indicating that lipoproteins organized in these vesicular structures do not act as pathogen-associated molecular patterns. In light of these findings, we propose to name these new structures Lipoprotein-rich Membrane Vesicles. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Gene expression platform for synthetic biology in the human pathogen Streptococcus pneumoniae.

    PubMed

    Sorg, Robin A; Kuipers, Oscar P; Veening, Jan-Willem

    2015-03-20

    The human pathogen Streptococcus pneumoniae (pneumococcus) is a bacterium that owes its success to complex gene expression regulation patterns on both the cellular and the population level. Expression of virulence factors enables a mostly hazard-free presence of the commensal, in balance with the host and niche competitors. Under specific circumstances, changes in this expression can result in a more aggressive behavior and the reversion to the invasive form as pathogen. These triggering conditions are very difficult to study due to the fact that environmental cues are often unknown or barely possible to simulate outside the host (in vitro). An alternative way of investigating expression patterns is found in synthetic biology approaches of reconstructing regulatory networks that mimic an observed behavior with orthogonal components. Here, we created a genetic platform suitable for synthetic biology approaches in S. pneumoniae and characterized a set of standardized promoters and reporters. We show that our system allows for fast and easy cloning with the BglBrick system and that reliable and robust gene expression after integration into the S. pneumoniae genome is achieved. In addition, the cloning system was extended to allow for direct linker-based assembly of ribosome binding sites, peptide tags, and fusion proteins, and we called this new generally applicable standard "BglFusion". The gene expression platform and the methods described in this study pave the way for employing synthetic biology approaches in S. pneumoniae.

  12. The Human Pathogen Streptococcus pyogenes Releases Lipoproteins as Lipoprotein-rich Membrane Vesicles*

    PubMed Central

    Biagini, Massimiliano; Garibaldi, Manuela; Aprea, Susanna; Pezzicoli, Alfredo; Doro, Francesco; Becherelli, Marco; Taddei, Anna Rita; Tani, Chiara; Tavarini, Simona; Mora, Marirosa; Teti, Giuseppe; D'Oro, Ugo; Nuti, Sandra; Soriani, Marco; Margarit, Immaculada; Rappuoli, Rino; Grandi, Guido; Norais, Nathalie

    2015-01-01

    Bacterial lipoproteins are attractive vaccine candidates because they represent a major class of cell surface-exposed proteins in many bacteria and are considered as potential pathogen-associated molecular patterns sensed by Toll-like receptors with built-in adjuvanticity. Although Gram-negative lipoproteins have been extensively characterized, little is known about Gram-positive lipoproteins. We isolated from Streptococcus pyogenes a large amount of lipoproteins organized in vesicles. These vesicles were obtained by weakening the bacterial cell wall with a sublethal concentration of penicillin. Lipid and proteomic analysis of the vesicles revealed that they were enriched in phosphatidylglycerol and almost exclusively composed of lipoproteins. In association with lipoproteins, a few hypothetical proteins, penicillin-binding proteins, and several members of the ExPortal, a membrane microdomain responsible for the maturation of secreted proteins, were identified. The typical lipidic moiety was apparently not necessary for lipoprotein insertion in the vesicle bilayer because they were also recovered from the isogenic diacylglyceryl transferase deletion mutant. The vesicles were not able to activate specific Toll-like receptor 2, indicating that lipoproteins organized in these vesicular structures do not act as pathogen-associated molecular patterns. In light of these findings, we propose to name these new structures Lipoprotein-rich Membrane Vesicles. PMID:26018414

  13. Presence of Helicobacter suis on pork carcasses.

    PubMed

    De Cooman, L; Houf, K; Smet, A; Flahou, B; Ducatelle, R; De Bruyne, E; Pasmans, F; Haesebrouck, F

    2014-09-18

    Helicobacter (H.) suis is a world-wide spread pathogen which not only colonizes the stomach of pigs, but is also the most prevalent gastric non-H. pylori Helicobacter (NHPH) species in humans. H. suis infections are associated with gastric lesions both in pigs and in humans. Recently, the presence of viable H. suis bacteria has been demonstrated in minced pork, suggesting that manipulation or consumption of contaminated pig meat is a possible route of transmission of this zoonotic agent. The main goal of this study was to determine the extent of pork carcass contamination with H. suis at slaughter. In two consecutive studies, the occurrence of H. suis DNA was assessed in scalding water, head and mouth swabs, mesenteric lymph nodes, palatine tonsils and on the chest, shoulder and ham region of pork carcasses from three slaughterhouses using qPCR with ureA gene based H. suis-specific primers. H. suis DNA was detected on carcasses in all slaughterhouses, in 8.3% of all 1083 samples. It was found in all sampled matrices, except for the palatine tonsils and scalding water samples. Contamination levels of dressed pork samples did not exceed 184 genomic equivalents per 100cm(2) (shoulder, ham) or 300cm(2) (chest). All positive PCR products were subjected to sequence analysis of the ureA gene to confirm the identification of H. suis bacteria. Using multilocus sequence typing (MLST) on a selection of the positive samples, 5 unique sequence types (STs) could be assigned. Multiple H. suis strains were present on samples derived from one specific pig herd. Since H. suis DNA was detected in 11% (n: 90) of the mesenteric lymph nodes derived at the slaughterhouse, it was determined whether these organisms can colonize the mesenteric lymph nodes after experimental infection. Despite high-level colonization of the porcine stomachs with the H. suis strain, no H. suis DNA was detected in the mesenteric lymph nodes at four weeks after experimental infection. This might indicate that

  14. Molecular mapping of the cell wall polysaccharides of the human pathogen Streptococcus agalactiae

    NASA Astrophysics Data System (ADS)

    Beaussart, Audrey; Péchoux, Christine; Trieu-Cuot, Patrick; Hols, Pascal; Mistou, Michel-Yves; Dufrêne, Yves F.

    2014-11-01

    The surface of many bacterial pathogens is covered with polysaccharides that play important roles in mediating pathogen-host interactions. In Streptococcus agalactiae, the capsular polysaccharide (CPS) is recognized as a major virulence factor while the group B carbohydrate (GBC) is crucial for peptidoglycan biosynthesis and cell division. Despite the important roles of CPS and GBC, there is little information available on the molecular organization of these glycopolymers on the cell surface. Here, we use atomic force microscopy (AFM) and transmission electron microscopy (TEM) to analyze the nanoscale distribution of CPS and GBC in wild-type (WT) and mutant strains of S. agalactiae. TEM analyses reveal that in WT bacteria, peptidoglycan is covered with a very thin (few nm) layer of GBC (the ``pellicle'') overlaid by a 15-45 nm thick layer of CPS (the ``capsule''). AFM-based single-molecule mapping with specific antibody probes shows that CPS is exposed on WT cells, while it is hardly detected on mutant cells impaired in CPS production (ΔcpsE mutant). By contrast, both TEM and AFM show that CPS is over-expressed in mutant cells altered in GBC expression (ΔgbcO mutant), indicating that the production of the two surface glycopolymers is coordinated in WT cells. In addition, AFM topographic imaging and molecular mapping with specific lectin probes demonstrate that removal of CPS (ΔcpsE), but not of GBC (ΔgbcO), leads to the exposure of peptidoglycan, organized into 25 nm wide bands running parallel to the septum. These results indicate that CPS forms a homogeneous barrier protecting the underlying peptidoglycan from environmental exposure, while the presence of GBC does not prevent peptidoglycan detection. This work shows that single-molecule AFM, combined with high-resolution TEM, represents a powerful platform for analysing the molecular arrangement of the cell wall polymers of bacterial pathogens.

  15. Stimulation of cadaverine production by foodborne pathogens in the presence of Lactobacillus, Lactococcus, and Streptococcus spp.

    PubMed

    Kuley, Esmeray; Balıkcı, Esra; Özoğul, Ilyas; Gökdogan, Saadet; Ozoğul, Fatih

    2012-12-01

    The effect of Lactobacillus plantarum (FI8595), Lactococcus lactis subsp. cremoris MG 1363), Lactococcus lactis subsp. lactis (IL 1403), and Streptococcus thermophilus on cadaverine and other biogenic amine production by foodborne pathogens was investigated lysine decarboxylase broth. Both of lactic acid bacteria and foodborne pathogens used (especially Staphylococcus aureus, E. coli, Lc. lactis subsp. lactis and Lb. plantarum) had an ability to convert aminoacids into biogenic amine. The conversion of lysine into cadaverine was the highest (167.11 mg/L) by Lactobacillus spp. Gram-positive bacteria generally had a greater ability to produce cadaverine with corresponding value of 46.26, 53.76, and 154.54 mg/L for Enterococcus faecalis, S. aureus, and Listeria monocytogenes, respectively. Significant variations on biogenic amine production were observed in the presence of lactic acid bacteria strains (P < 0.05). The role of lactic acid bacteria on biogenic amine production by foodborne pathogens varied depending on strains and specific amine. Cadaverine accumulation by Enterobactericeae was increased in the presence of lactic acid bacteria strains except for St. thermophilus, which induced 2-fold lower cadaverine production by S. Paratyphi A. Lc. lactis subsp. lactis and Lc. lactis subsp. cremoris induced 10-fold higher increases in histamine for E. coli and K. pneumoniae, respectively. Lactic acid bacteria resulted in strong increases in cadaverine production by P. aeruginosa, although remarkable decreases were observed for histamine, spermidine, dopamine, agmatine, and TMA in the presence of lactic acid bacteria in lysine decarboxylase broth . The result of the study showed that amine positive lactic acid bacteria strains in fermented food led to significant amine accumulation by contaminant bacteria and their accumulation in food product may be controlled by the use of proper starters with amine-negative activity. © 2012 Institute of Food Technologists®

  16. In vitro reconstitution of peptidoglycan assembly from the Gram-positive pathogen Streptococcus pneumoniae.

    PubMed

    Zapun, André; Philippe, Jules; Abrahams, Katherine A; Signor, Luca; Roper, David I; Breukink, Eefjan; Vernet, Thierry

    2013-12-20

    Understanding the molecular basis of bacterial cell wall assembly is of paramount importance in addressing the threat of increasing antibiotic resistance worldwide. Streptococcus pneumoniae presents a particularly acute problem in this respect, as it is capable of rapid evolution by homologous recombination with related species. Resistant strains selected by treatment with β-lactams express variants of the target enzymes that do not recognize the drugs but retain their activity in cell wall building, despite the antibiotics being mimics of the natural substrate. Until now, the crucial transpeptidase activity that is inhibited by β-lactams was not amenable to in vitro investigation with enzymes from Gram-positive organisms, including streptococci, staphylococci, or enterococci pathogens. We report here for the first time the in vitro assembly of peptidoglycan using recombinant penicillin-binding proteins from pneumococcus and the precursor lipid II. The two required enzymatic activities, glycosyl transferase for elongating glycan chains and transpeptidase for cross-linking stem-peptides, were observed. Most importantly, the transpeptidase activity was dependent on the chemical nature of the stem-peptide. Amidation of the second residue glutamate into iso-glutamine by the recently discovered amido-transferase MurT/GatD is required for efficient cross-linking of the peptidoglycan.

  17. Initial steps in Streptococcus pneumoniae interaction with and pathogenicity to the host.

    PubMed

    Shani-Sekler, M; Lifshitz, S; Hillel, I; Dagan, R; Grossman, N; Fleminger, G; Mizrachi-Brauner, Y

    2000-01-01

    Streptococcus pneumoniae (Pnc) is one of the leading pathogens in the world. Attachment to respiratory mucosal and lung surfaces is presumed to be involved in carriage, in disease and in the interaction with macrophages initiating innate immune responses. We hypothesized that bacterial adhesins mediate Pnc adhesion and host cell invasiveness. Initial studies have focused on the purification of cell wall and membrane proteins using fetuin affinity chromatography, SDS PAGE and western blot analysis probed with pooled healthy human sera. Using a Pnc clinical isolate, and a gpt mutant we have detected 10-lectin proteins isolated from the cell wall and adherent to the affinity column and 15 lectins isolated from membrane extracts. The fetuin-captured lectins agglutinated rabbit erythrocytes. 15 proteins in the cell wall and 18 proteins in the membrane that failed to bind to the fetuin column did not agglutinate rabbit erythrocytes. Further purification of the cell wall and membrane fetuin-separated fractions was achieved via anion exchange FPLC, was verified by SDS PAGE. These proteins maintained their agglutinating activity, and were subsequently tested for their ability to interfere with Pnc adhesion and invasion of epithelial cells in culture. Additional biochemical, immunological and molecular techniques are being used in attempt to identify relevant proteins.

  18. Regulatory Rewiring Confers Serotype-Specific Hyper-Virulence in the Human Pathogen Group A Streptococcus

    PubMed Central

    Miller, Eric W.; Danger, Jessica L.; Ramalinga, Anupama B.; Horstmann, Nicola; Shelburne, Samuel A.; Sumby, Paul

    2015-01-01

    Summary Phenotypic heterogeneity is commonly observed between isolates of a given pathogen. Epidemiological analyses have identified that some serotypes of the group A Streptococcus (GAS) are non-randomly associated with particular disease manifestations. Here, we present evidence that a contributing factor to the association of serotype M3 GAS isolates with severe invasive infections is the presence of a null mutant allele for the orphan kinase RocA. Through use of RNAseq analysis, we identified that the natural rocA mutation present within M3 isolates leads to the enhanced expression of more than a dozen immunomodulatory virulence factors, enhancing phenotypes such as hemolysis and NAD+ hydrolysis. Consequently, an M3 GAS isolate survived human phagocytic killing at a level 13-fold higher than a rocA complemented derivative, and was significantly more virulent in a murine bacteremia model of infection. Finally, we identified that RocA functions through the CovR/S two-component system as levels of phosphorylated CovR increase in the presence of functional RocA, and RocA has no regulatory activity following covR or covS mutation. Our data are consistent with RocA interfacing with the CovR/S two-component system, and that the absence of this activity in M3 GAS potentiates the severity of invasive infections caused by isolates of this serotype. PMID:26192205

  19. Novel Bacteriophage Lysin with Broad Lytic Activity Protects against Mixed Infection by Streptococcus pyogenes and Methicillin-Resistant Staphylococcus aureus

    PubMed Central

    Gilmer, Daniel B.; Schmitz, Jonathan E.; Euler, Chad W.

    2013-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pyogenes (group A streptococcus [GrAS]) cause serious and sometimes fatal human diseases. They are among the many Gram-positive pathogens for which resistance to leading antibiotics has emerged. As a result, alternative therapies need to be developed to combat these pathogens. We have identified a novel bacteriophage lysin (PlySs2), derived from a Streptococcus suis phage, with broad lytic activity against MRSA, vancomycin-intermediate S. aureus (VISA), Streptococcus suis, Listeria, Staphylococcus simulans, Staphylococcus epidermidis, Streptococcus equi, Streptococcus agalactiae (group B streptococcus [GBS]), S. pyogenes, Streptococcus sanguinis, group G streptococci (GGS), group E streptococci (GES), and Streptococcus pneumoniae. PlySs2 has an N-terminal cysteine-histidine aminopeptidase (CHAP) catalytic domain and a C-terminal SH3b binding domain. It is stable at 50°C for 30 min, 37°C for >24 h, 4°C for 15 days, and −80°C for >7 months; it maintained full activity after 10 freeze-thaw cycles. PlySs2 at 128 μg/ml in vitro reduced MRSA and S. pyogenes growth by 5 logs and 3 logs within 1 h, respectively, and exhibited a MIC of 16 μg/ml for MRSA. A single, 2-mg dose of PlySs2 protected 92% (22/24) of the mice in a bacteremia model of mixed MRSA and S. pyogenes infection. Serially increasing exposure of MRSA and S. pyogenes to PlySs2 or mupirocin resulted in no observed resistance to PlySs2 and resistance to mupirocin. To date, no other lysin has shown such notable broad lytic activity, stability, and efficacy against multiple, leading, human bacterial pathogens; as such, PlySs2 has all the characteristics to be an effective therapeutic. PMID:23571534

  20. Isopeptide bonds block the mechanical extension of pili in pathogenic Streptococcus pyogenes.

    PubMed

    Alegre-Cebollada, Jorge; Badilla, Carmen L; Fernández, Julio M

    2010-04-09

    In the early stages of an infection, pathogenic bacteria use long fibrous structures known as pili as adhesive anchors for attachment to the host cells. These structures also play key roles in colony and biofilm formation. In all those processes, pili must withstand large mechanical forces. The pili of the nasty gram-positive human pathogen Streptococcus pyogenes are assembled as single, micrometer long tandem modular proteins of covalently linked repeats of pilin proteins. Here we use single molecule force spectroscopy techniques to study the mechanical properties of the major pilin Spy0128. In our studies, we engineer polyproteins containing repeats of Spy0128 flanked by the well characterized I27 protein which provides an unambiguous mechanical fingerprint. We find that Spy0128 is an inextensible protein, even when pulled at forces of up to 800 pN. We also found that this remarkable mechanical resilience, unique among the modular proteins studied to date, results from the strategically located intramolecular isopeptide bonds recently identified in the x-ray structure of Spy0128. Removal of the isopeptide bonds by mutagenesis readily allowed Spy0128 domains to unfold and extend, albeit at relatively high forces of 172 pN (N-terminal domain) or 250 pN (C-terminal domain). Our results show that in contrast to the elastic roles played by large tandem modular proteins such as titin and fibronectin, the giant pili of S. pyogenes evolved to abrogate mechanical extensibility, a property that may be crucial in the pathogenesis of this most virulent bacterium and, therefore, become the target of new therapeutic approaches against its infections.

  1. Characterization of a novel Streptococcus suis endolysin and development of a multi-acting antimicrobial enzyme that is refractory to resistance development

    USDA-ARS?s Scientific Manuscript database

    The crisis of increasing resistance of pathogenic bacteria to classical antibiotics has driven research towards identification of other means to fight infectious disease. One particularly attractive option is the use of bacteriophage-encoded peptidoglycan hydrolases (endolysins). These enzymes are a...

  2. Transcriptional Profiling of the Oral Pathogen Streptococcus mutans in Response to Competence Signaling Peptide XIP

    PubMed Central

    Wenderska, Iwona B.; Latos, Andrew; Pruitt, Benjamin; Palmer, Sara; Spatafora, Grace

    2017-01-01

    ABSTRACT In the cariogenic Streptococcus mutans, competence development is regulated by the ComRS signaling system comprised of the ComR regulator and the ComS prepeptide to the competence signaling peptide XIP (ComX-inducing peptide). Aside from competence development, XIP signaling has been demonstrated to regulate cell lysis, and recently, the expression of bacteriocins, small antimicrobial peptides used by bacteria to inhibit closely related species. Our study further explores the effect of XIP signaling on the S. mutans transcriptome. RNA sequencing revealed that XIP induction resulted in a global change in gene expression that was consistent with a stress response. An increase in several membrane-bound regulators, including HdrRM and BrsRM, involved in bacteriocin production, and the VicRKX system, involved in acid tolerance and biofilm formation, was observed. Furthermore, global changes in gene expression corresponded to changes observed during the stringent response to amino acid starvation. Effects were also observed on genes involved in sugar transport and carbon catabolite repression and included the levQRST and levDEFG operons. Finally, our work identified a novel heat shock-responsive intergenic region, encoding a small RNA, with a potential role in competence shutoff. IMPORTANCE Genetic competence provides bacteria with an opportunity to increase genetic diversity or acquire novel traits conferring a survival advantage. In the cariogenic pathogen Streptococcus mutans, DNA transformation is regulated by the competence stimulating peptide XIP (ComX-inducing peptide). The present study utilizes high-throughput RNA sequencing (RNAseq) to provide a greater understanding of how global gene expression patterns change in response to XIP. Overall, our work demonstrates that in S. mutans, XIP signaling induces a response that resembles the stringent response to amino acid starvation. We further identify a novel heat shock-responsive intergenic region with a

  3. Evaluation of the presence and zoonotic transmission of Chlamydia suis in a pig slaughterhouse.

    PubMed

    De Puysseleyr, Kristien; De Puysseleyr, Leentje; Dhondt, Hendrik; Geens, Tom; Braeckman, Lutgart; Morré, Servaas A; Cox, Eric; Vanrompay, Daisy

    2014-10-30

    A significant number of studies on pig farms and wild boars worldwide, demonstrate the endemic presence of Chlamydia suis in pigs. However, the zoonotic potential of this pathogen, phylogenetically closely related to Chlamydia trachomatis, is still uninvestigated. Therefore, this study aims to examine the zoonotic transmission in a Belgian pig abattoir. Presence of Chlamydia suis in pigs, contact surfaces, air and employees was assessed using a Chlamydia suis specific real-time PCR and culture. Furthermore, Chlamydia suis isolates were tested for the presence of the tet(C) gene. Chlamydia suis bacteria could be demonstrated in samples from pigs, the air and contact surfaces. Moreover, eye swabs of two employees were positive for Chlamydia suis by both PCR and culture. The tet(C) gene was absent in both human Chlamydia suis isolates and no clinical signs were reported. These findings suggest the need for further epidemiological and clinical research to elucidate the significance of human ocular Chlamydia suis infections.

  4. Virulence factor regulation and regulatory networks in Streptococcus pyogenes and their impact on pathogen-host interactions.

    PubMed

    Kreikemeyer, Bernd; McIver, Kevin S; Podbielski, Andreas

    2003-05-01

    Streptococcus pyogenes (group A streptococcus, GAS) is a very important human pathogen with remarkable adaptation capabilities. Survival within the harsh host surroundings requires sensing potential on the bacterial side, which leads in particular to coordinately regulated virulence factor expression. GAS 'stand-alone' response regulators (RRs) and two-component signal transduction systems (TCSs) link the signals from the host environment with adaptive responses of the bacterial cell. Numerous putative regulatory systems emerged from GAS genome sequences. Only three RRs [Mga, RofA-like protein (RALP) and Rgg/RopB] and three TCSs (CsrRS/CovRS, FasBCAX and Ihk/Irr) have been studied in some detail with respect to their growth-phase-dependent activity and their influence on GAS-host cell interaction. In particular, the Mga-, RALP- and Rgg/RopB-regulated pathways display interconnected activities that appear to influence GAS colonization, persistence and spreading mechanisms, in a growth-phase-related fashion. Here, we have summarized our current knowledge about these RRs and TCSs to highlight the questions that should be addressed in future research on GAS pathogenicity.

  5. Group A streptococcus cell-associated pathogenic proteins as revealed by growth in hyaluronic acid-enriched media.

    PubMed

    Zhang, Meng; McDonald, Fiona M; Sturrock, Shane S; Charnock, Simon J; Humphery-Smith, Ian; Black, Gary W

    2007-05-01

    Group A streptococcus (GAS), also know as Streptococcus pyogenes, is a human pathogen and can cause several fatal invasive diseases such as necrotising fasciitis, the so-called flesh-eating disease, and toxic shock syndrome. The destruction of connective tissue and the hyaluronic acid (HA) therein, is a key element of GAS pathogenesis. We therefore propagated GAS in HA-enriched growth media in an attempt to create a simple biological system that could reflect some elements of GAS pathogenesis. Our results show that several recognised virulence factors were up-regulated in HA-enriched media, including the M1 protein, a collagen-like surface protein and the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase, which has been shown to play important roles in streptococcal pathogenesis. Interestingly, two hypothetical proteins of unknown function were also up-regulated and detailed bioinformatics analysis showed that at least one of these hypothetical proteins is likely to be involved in pathogenesis. It was therefore concluded that this simple biological system provided a valuable tool for the identification of potential GAS virulence factors.

  6. Investigations of selected pathogens among village pigs in Central Papua, Indonesia.

    PubMed

    Nugroho, Widi; Cargill, Colin Frank; Putra, I Made; Kirkwood, Roy Neville; Trott, Darren John; Salasia, Siti Isrina Oktavia; Slipranata, Mitra; Reichel, Michael Philipp

    2016-01-01

    Village pig husbandry is an important part of livestock production in Papua Province, Eastern Indonesia. However, high level of disease and mortality constrains production. The aim of this study was to investigate the prevalence of the selected pathogens in village pigs in the Jayawijaya Region of Papua Province, Indonesia. Two studies were conducted: Study 1 determined the prevalence of selected pathogens in dead or moribund pigs sent to the main local market for sale. Study 2 recorded the prevalence of the selected pathogens, on pig farms in the Subdistrict of Wamena that had not recorded a case of pig mortality during the duration of Study 1. Blood samples of individuals from both groups were tested for CSF antigen and antibody, as well as antibody against PCV2. Organs with evident pathological changes from Study 1 and tonsilar swabs from Study 2 were subjected to bacteriological culture and identification of Streptococcus suis and Streptococcus zooepidemicus. Faecal samples from both studies were examined for eggs of strongyle parasites, Trichuris suis, Ascaris suum, Strongyloides ransomi and coccidia. The main infections in both studies were CSF, PCV2 and strongyle parasites, but prevalence was higher in Study 1 (P < 0.05). T. suis and S. zooepidemicus were prevalent in pigs in Study 1, but rare in healthy pigs (P < 0.05). Infections with coccidia, A. suum and S. ransomi were common but did not differ between groups (P < 0.05), with S. suis infections uncommon in both studies. This suggests that infections with CSF, PCV2, strongyle and T. suis are important pathogens in village pig farms in Jayawijaya. Local pig husbandry practices, such as confining pigs and heat-treating pig feeds, may be practical solutions to help minimize infection in village pigs in Jayawijaya.

  7. The Complete Genome of Brucella Suis 019 Provides Insights on Cross-Species Infection

    PubMed Central

    Wang, Yuanzhi; Wang, Zhen; Chen, Xin; Zhang, Hui; Guo, Fei; Zhang, Ke; Feng, Hanping; Gu, Wenyi; Wu, Changxin; Ma, Lei; Li, Tiansen; Chen, Chuangfu; Gao, Shan

    2016-01-01

    Brucella species are the most important zoonotic pathogens worldwide and cause considerable harm to humans and animals. In this study, we presented the complete genome of B. suis 019 isolated from sheep (ovine) with epididymitis. B. suis 019 has a rough phenotype and can infect sheep, rhesus monkeys and possibly humans. The comparative genome analysis demonstrated that B. suis 019 is closest to the vaccine strain B. suis bv. 1 str. S2. Further analysis associated the rsh gene to the pathogenicity of B. suis 019, and the WbkA gene to the rough phenotype of B. suis 019. The 019 complete genome data was deposited in the GenBank database with ID PRJNA308608. PMID:26821047

  8. Identification of 88 regulatory small RNAs in the TIGR4 strain of the human pathogen Streptococcus pneumoniae

    PubMed Central

    Acebo, Paloma; Martin-Galiano, Antonio J.; Navarro, Sara; Zaballos, Ángel; Amblar, Mónica

    2012-01-01

    Streptococcus pneumoniae is the main etiological agent of community-acquired pneumonia and a major cause of mortality and morbidity among children and the elderly. Genome sequencing of several pneumococcal strains revealed valuable information about the potential proteins and genetic diversity of this prevalent human pathogen. However, little is known about its transcriptional regulation and its small regulatory noncoding RNAs. In this study, we performed deep sequencing of the S. pneumoniae TIGR4 strain RNome to identify small regulatory RNA candidates expressed in this pathogen. We discovered 1047 potential small RNAs including intragenic, 5′- and/or 3′-overlapping RNAs and 88 small RNAs encoded in intergenic regions. With this approach, we recovered many of the previously identified intergenic small RNAs and identified 68 novel candidates, most of which are conserved in both sequence and genomic context in other S. pneumoniae strains. We confirmed the independent expression of 17 intergenic small RNAs and predicted putative mRNA targets for six of them using bioinformatics tools. Preliminary results suggest that one of these six is a key player in the regulation of competence development. This study is the biggest catalog of small noncoding RNAs reported to date in S. pneumoniae and provides a highly complete view of the small RNA network in this pathogen. PMID:22274957

  9. New Bruce-ladder multiplex PCR assay for the biovar typing of Brucella suis and the discrimination of Brucella suis and Brucella canis.

    PubMed

    López-Goñi, Ignacio; García-Yoldi, David; Marín, Clara M; de Miguel, María J; Barquero-Calvo, Elías; Guzmán-Verri, Caterina; Albert, David; Garin-Bastuji, Bruno

    2011-12-29

    Rapid and specific identification of Brucella suis at the biovar level is necessary because some of the biovars that infect animals are pathogenic for humans. None of the molecular typing methods described so far are able to discriminate B. suis biovars in a single test and differentiation of B. suis from Brucella canis by molecular approaches can be difficult. This article describes a new multiplex PCR assay, Suis-ladder, for fast and accurate identification of B. suis at the biovar level and the differentiation of B. suis, B. canis and Brucella microti. An advancement of the original Bruce-ladder PCR protocol which allows the correct discrimination of all known Brucella species is also described. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Sequencing and comparative genome analysis of two pathogenic Streptococcus gallolyticus subspecies: genome plasticity, adaptation and virulence.

    PubMed

    Lin, I-Hsuan; Liu, Tze-Tze; Teng, Yu-Ting; Wu, Hui-Lun; Liu, Yen-Ming; Wu, Keh-Ming; Chang, Chuan-Hsiung; Hsu, Ming-Ta

    2011-01-01

    Streptococcus gallolyticus infections in humans are often associated with bacteremia, infective endocarditis and colon cancers. The disease manifestations are different depending on the subspecies of S. gallolyticus causing the infection. Here, we present the complete genomes of S. gallolyticus ATCC 43143 (biotype I) and S. pasteurianus ATCC 43144 (biotype II.2). The genomic differences between the two biotypes were characterized with comparative genomic analyses. The chromosome of ATCC 43143 and ATCC 43144 are 2,36 and 2,10 Mb in length and encode 2246 and 1869 CDS respectively. The organization and genomic contents of both genomes were most similar to the recently published S. gallolyticus UCN34, where 2073 (92%) and 1607 (86%) of the ATCC 43143 and ATCC 43144 CDS were conserved in UCN34 respectively. There are around 600 CDS conserved in all Streptococcus genomes, indicating the Streptococcus genus has a small core-genome (constitute around 30% of total CDS) and substantial evolutionary plasticity. We identified eight and five regions of genome plasticity in ATCC 43143 and ATCC 43144 respectively. Within these regions, several proteins were recognized to contribute to the fitness and virulence of each of the two subspecies. We have also predicted putative cell-surface associated proteins that could play a role in adherence to host tissues, leading to persistent infections causing sub-acute and chronic diseases in humans. This study showed evidence that the S. gallolyticus still possesses genes making it suitable in a rumen environment, whereas the ability for S. pasteurianus to live in rumen is reduced. The genome heterogeneity and genetic diversity among the two biotypes, especially membrane and lipoproteins, most likely contribute to the differences in the pathogenesis of the two S. gallolyticus biotypes and the type of disease an infected patient eventually develops.

  11. Sequencing and Comparative Genome Analysis of Two Pathogenic Streptococcus gallolyticus Subspecies: Genome Plasticity, Adaptation and Virulence

    PubMed Central

    Teng, Yu-Ting; Wu, Hui-Lun; Liu, Yen-Ming; Wu, Keh-Ming; Chang, Chuan-Hsiung; Hsu, Ming-Ta

    2011-01-01

    Streptococcus gallolyticus infections in humans are often associated with bacteremia, infective endocarditis and colon cancers. The disease manifestations are different depending on the subspecies of S. gallolyticus causing the infection. Here, we present the complete genomes of S. gallolyticus ATCC 43143 (biotype I) and S. pasteurianus ATCC 43144 (biotype II.2). The genomic differences between the two biotypes were characterized with comparative genomic analyses. The chromosome of ATCC 43143 and ATCC 43144 are 2,36 and 2,10 Mb in length and encode 2246 and 1869 CDS respectively. The organization and genomic contents of both genomes were most similar to the recently published S. gallolyticus UCN34, where 2073 (92%) and 1607 (86%) of the ATCC 43143 and ATCC 43144 CDS were conserved in UCN34 respectively. There are around 600 CDS conserved in all Streptococcus genomes, indicating the Streptococcus genus has a small core-genome (constitute around 30% of total CDS) and substantial evolutionary plasticity. We identified eight and five regions of genome plasticity in ATCC 43143 and ATCC 43144 respectively. Within these regions, several proteins were recognized to contribute to the fitness and virulence of each of the two subspecies. We have also predicted putative cell-surface associated proteins that could play a role in adherence to host tissues, leading to persistent infections causing sub-acute and chronic diseases in humans. This study showed evidence that the S. gallolyticus still possesses genes making it suitable in a rumen environment, whereas the ability for S. pasteurianus to live in rumen is reduced. The genome heterogeneity and genetic diversity among the two biotypes, especially membrane and lipoproteins, most likely contribute to the differences in the pathogenesis of the two S. gallolyticus biotypes and the type of disease an infected patient eventually develops. PMID:21633709

  12. Association of Streptococcus pluranimalium with valvular endocarditis and septicaemia in adult broiler parents.

    PubMed

    Hedegaard, L; Christensen, H; Chadfield, M S; Christensen, J P; Bisgaard, M

    2009-04-01

    The genus Streptococcus consists of more than 60 species, but only Streptococcus equi subspecies zooepidemicus, Streptococcus gallolyticus ssp. gallolyticus, Streptococcus gallinaceus, Streptococcus dysgalactiae, Streptococcus mutans and Streptococcus suis have been isolated from poultry. During investigations of the aetiology of increased mortality in broiler parent stock at the end of production, pure cultures of streptococcal-like organisms that could not be classified among these six species were obtained from 24 cases of septicaemia or valvular endocarditis and septicaemia. Phenotypic characterization using the API20 STREP kit identified the isolates as Aerococcus viridans (10), Aerococcus urinae (2), Leuconostoc species (4), Streptococcus salivarius (2), Streptococcus bovis II 3 (1), Enterococcus avium (3), Enterococcus faecium (1) or Gemella morbillorum (1). However, this identification was misleading as subsequent genetic investigations using pulse field gel electrophoresis and sequencing of 16S rRNA genes showed that 19 isolates were classified as Streptococcus pluranimalium, while the remaining isolates were E. avium (3), E. faecium (1) or Lactobacillus species (1). Misidentification by API20 STREP was related to the database provided by the manufacturer, as the phenotypic characteristics could identify these organisms as S. pluranimalium. The isolates of S. pluranimalium belonged to at least three different clones as determined by pulsed field gel electrophoresis of SmaI-digested genomic DNA. The capacity that these isolates had to colonize the valvular endothelium was suggested by the occurrence of valvular endocarditis in 12 of 19 cases. Demonstration of the same clone in all four houses on a farm suggested the pathogenic potential of this organism.

  13. Inhibitory Effect of Dodonaea viscosa var. angustifolia on the Virulence Properties of the Oral Pathogens Streptococcus mutans and Porphyromonas gingivalis

    PubMed Central

    Owotade, Foluso John

    2013-01-01

    Aim. This study investigated the effect of Dodonaea viscosa var. angustifolia (DVA) on the virulence properties of cariogenic Streptococcus mutans and Porphyromonas gingivalis implicated in periodontal diseases. Methods. S. mutans was cultured in tryptone broth containing a crude leaf extract of DVA for 16 hours, and the pH was measured after 10, 12, 14, and 16 h. Biofilms of S. mutans were grown on glass slides for 48 hours and exposed to plant extract for 30 minutes; the adherent cells were reincubated and the pH was measured at various time intervals. Minimum bactericidal concentration of the extracts against the four periodontal pathogens was determined. The effect of the subinhibitory concentration of plant extract on the production of proteinases by P. gingivalis was also evaluated. Results. DVA had no effect on acid production by S. mutans biofilms; however, it significantly inhibited acid production in planktonic cells. Periodontal pathogens were completely eliminated at low concentrations ranging from 0.09 to 0.02 mg/mL of crude plant extracts. At subinhibitory concentrations, DVA significantly reduced Arg-gingipain (24%) and Lys-gingipain (53%) production by P. gingivalis (P ≤ 0.01). Conclusions. These results suggest that DVA has the potential to be used to control oral infections including dental caries and periodontal diseases. PMID:24223061

  14. [The prevalence of different Streptococcus pneumoniaе serotypes in the children presenting with ENT infections or carrying nasopharyngeal pathogens].

    PubMed

    Boronina, L G; Samatova, E V; Druĭ, A E; Panina, E Iu; Kochneva, N A; Vodovoz, N Iu; Murunova, N V; Gruzdev, A I; Lakhno, T I

    2013-01-01

    The objective of the present study was to elucidate the etiopathological significance of various Streptococcus pneumoniae serotypes in the children presenting with ENT infections and carrying nasopharyngeal pathogens. The incidence of the latter condition was 19.5% in the children free from S. pneumoniae infection in comparison with 20.9% and 30.7% in those having diagnosis of otitis media and rhinosinusitis respectively. Fifty five (88.8%) of the 62 isolated streptococcal strains were grouped into types with the use of multiplex PCR. Twelve serotypes were identified in the patients presenting with rhinosinusitis with the predominance of 6A/6B and 3 (40.5%) compared with seven isolated from the carriers of nasopharyngeal pathogens. In this group, type 3 also prevailed (26.5%) whereas other serotypes occurred less frequently: 23F (13,4%), indivisible totality of 8, 9V, 9A, 1F, 11A, 211B, 11C, 11D, 12F, 15A, and 33F (13.4%), 20 (6.7%), 19A (6.7%), 14 (6.7%), 6A,6B (6.7%). The serotypes of S. pneumoniae isolated from the patients with rhinosinusitis were found to show 55.3% identity with those present in the composition of the conjugated 7-valent pneumococcal vaccines, 63.2% identity with the 10-valent vaccine, 81.6% identity with the 11p-valnet vaccine, and 84.2% identity with the 13-valent vaccine.

  15. A Multi-Serotype Approach Clarifies the Catabolite Control Protein A Regulon in the Major Human Pathogen Group A Streptococcus

    PubMed Central

    DebRoy, Sruti; Saldaña, Miguel; Travisany, Dante; Montano, Andrew; Galloway-Peña, Jessica; Horstmann, Nicola; Yao, Hui; González, Mauricio; Maass, Alejandro; Latorre, Mauricio; Shelburne, Samuel A.

    2016-01-01

    Catabolite control protein A (CcpA) is a highly conserved, master regulator of carbon source utilization in gram-positive bacteria, but the CcpA regulon remains ill-defined. In this study we aimed to clarify the CcpA regulon by determining the impact of CcpA-inactivation on the virulence and transcriptome of three distinct serotypes of the major human pathogen Group A Streptococcus (GAS). CcpA-inactivation significantly decreased GAS virulence in a broad array of animal challenge models consistent with the idea that CcpA is critical to gram-positive bacterial pathogenesis. Via comparative transcriptomics, we established that the GAS CcpA core regulon is enriched for highly conserved CcpA binding motifs (i.e. cre sites). Conversely, strain-specific differences in the CcpA transcriptome seems to consist primarily of affected secondary networks. Refinement of cre site composition via analysis of the core regulon facilitated development of a modified cre consensus that shows promise for improved prediction of CcpA targets in other medically relevant gram-positive pathogens. PMID:27580596

  16. Insight into the Evolution of the Histidine Triad Protein (HTP) Family in Streptococcus

    PubMed Central

    Pan, Xiu-Zhen; Wang, Bin; Chen, Jian-Qun

    2013-01-01

    The Histidine Triad Proteins (HTPs), also known as Pht proteins in Streptococcus pneumoniae, constitute a family of surface-exposed proteins that exist in many pathogenic streptococcal species. Although many studies have revealed the importance of HTPs in streptococcal physiology and pathogenicity, little is known about their origin and evolution. In this study, after identifying all htp homologs from 105 streptococcal genomes representing 38 different species/subspecies, we analyzed their domain structures, positions in genome, and most importantly, their evolutionary histories. By further projecting this information onto the streptococcal phylogeny, we made several major findings. First, htp genes originated earlier than the Streptococcus genus and gene-loss events have occurred among three streptococcal groups, resulting in the absence of the htp gene in the Bovis, Mutans and Salivarius groups. Second, the copy number of htp genes in other groups of Streptococcus is variable, ranging from one to four functional copies. Third, both phylogenetic evidence and domain structure analyses support the division of two htp subfamilies, designated as htp I and htp II. Although present mainly in the pyogenic group and in Streptococcus suis, htp II members are distinct from htp I due to the presence of an additional leucine-rich-repeat domain at the C-terminus. Finally, htp genes exhibit a faster nucleotide substitution rate than do housekeeping genes. Specifically, the regions outside the HTP domains are under strong positive selection. This distinct evolutionary pattern likely helped Streptococcus to easily escape from recognition by host immunity. PMID:23527301

  17. Insight into the evolution of the histidine triad protein (HTP) family in Streptococcus.

    PubMed

    Shao, Zhu-Qing; Zhang, Yan-Mei; Pan, Xiu-Zhen; Wang, Bin; Chen, Jian-Qun

    2013-01-01

    The Histidine Triad Proteins (HTPs), also known as Pht proteins in Streptococcus pneumoniae, constitute a family of surface-exposed proteins that exist in many pathogenic streptococcal species. Although many studies have revealed the importance of HTPs in streptococcal physiology and pathogenicity, little is known about their origin and evolution. In this study, after identifying all htp homologs from 105 streptococcal genomes representing 38 different species/subspecies, we analyzed their domain structures, positions in genome, and most importantly, their evolutionary histories. By further projecting this information onto the streptococcal phylogeny, we made several major findings. First, htp genes originated earlier than the Streptococcus genus and gene-loss events have occurred among three streptococcal groups, resulting in the absence of the htp gene in the Bovis, Mutans and Salivarius groups. Second, the copy number of htp genes in other groups of Streptococcus is variable, ranging from one to four functional copies. Third, both phylogenetic evidence and domain structure analyses support the division of two htp subfamilies, designated as htp I and htp II. Although present mainly in the pyogenic group and in Streptococcus suis, htp II members are distinct from htp I due to the presence of an additional leucine-rich-repeat domain at the C-terminus. Finally, htp genes exhibit a faster nucleotide substitution rate than do housekeeping genes. Specifically, the regions outside the HTP domains are under strong positive selection. This distinct evolutionary pattern likely helped Streptococcus to easily escape from recognition by host immunity.

  18. A beneficial aspect of a CB1 cannabinoid receptor antagonist: SR141716A is a potent inhibitor of macrophage infection by the intracellular pathogen Brucella suis.

    PubMed

    Gross, A; Terraza, A; Marchant, J; Bouaboula, M; Ouahrani-Bettache, S; Liautard, J P; Casellas, P; Dornand, J

    2000-03-01

    The psychoactive component of marijuana, delta9-tetrahydrocannabinol (THC) suppresses different functions of immunocytes, including the antimicrobicidal activity of macrophages. The triggering of cannabinoid receptors of CB1 and CB2 subtypes present on leukocytes may account for these effects. We investigated the influence of specific CB1 or CB2 receptor antagonists (SR141716A and SR144528, respectively) and nonselective CB1/CB2 cannabinoid receptor agonists (CP55,940 or WIN 55212-2) on macrophage infection by Brucella suis, an intracellular gram-negative bacteria. None of the compounds tested affected bacterial phagocytosis. By contrast, the intracellular multiplication of Brucella was dose-dependently inhibited in cells treated with 10-500 nM SR141716A and 1 microM SR141716A-induced cells exerted a potent microbicidal effect against the bacteria. SR144528, CP55,940, or WIN 55212-2 did not affect (or slightly potentiated) the growth of phagocytized bacteria. However, CP55,940 or WIN 55212-2 reversed the SR141716A-mediated effect, which strongly suggested an involvement of macrophage CB1 receptors in the phenomenon. SR141716A was able to pre-activate macrophages and to trigger an activation signal that inhibited Brucella development. The participation of endogenous cannabinoid ligand(s) in Brucella infection was discussed. Finally, our data show that SR141716A up-regulates the antimicrobial properties of macrophages in vitro and might be a pharmaceutical compound useful for counteracting the development of intramacrophagic gram-negative bacteria.

  19. Genome Sequences of Two Brucella suis Strains Isolated from the Same Patient, 8 Years Apart

    PubMed Central

    Viana, Marcus Vinicius Canário; Govil Batra, Dhwani; Boisvert, Sébastien; Brettin, Thomas Scott; Frace, Michael; Xia, Fangfang; Azevedo, Vasco; Tiller, Rebekah; Hoffmaster, Alex R.

    2017-01-01

    ABSTRACT Brucella suis is a Gram-negative, facultative intracellular pathogen that has pigs as its preferred host, but it can also infect humans. Here, we report the draft genome sequences of two B. suis strains that were isolated from the same patient, 8 years apart. PMID:28254974

  20. Antibacterial effect of water-soluble chitosan on representative dental pathogens Streptococcus mutans and Lactobacilli brevis

    PubMed Central

    CHEN, Chih-YU; CHUNG, Ying-CHIEN

    2012-01-01

    Dental caries is still a major oral health problem in most industrialized countries. The development of dental caries primarily involves Lactobacilli spp. and Streptococcus mutans. Although antibacterial ingredients are used against oral bacteria to reduce dental caries, some reports that show partial antibacterial ingredients could result in side effects. Objectives The main objective is to test the antibacterial effect of water-soluble chitosan while the evaluation of the mouthwash appears as a secondary aim. Material and Methods The chitosan was obtained from the Application Chemistry Company (Taiwan). The authors investigated the antibacterial effects of water-soluble chitosan against oral bacteria at different temperatures (25-37ºC) and pH values (pH 5-8), and evaluated the antibacterial activities of a self-made water-soluble chitosan-containing mouthwash by in vitro and in vivo experiments, and analyzed the acute toxicity of the mouthwashes. The acute toxicity was analyzed with the pollen tube growth (PTG) test. The growth inhibition values against the logarithmic scale of the test concentrations produced a concentrationresponse curve. The IC50 value was calculated by interpolation from the data. Results The effect of the pH variation (5-8) on the antibacterial activity of water-soluble chitosan against tested oral bacteria was not significant. The maximal antibacterial activity of water-soluble chitosan occurred at 37ºC. The minimum bactericidal concentration (MBC) of water-soluble chitosan on Streptococcus mutans and Lactobacilli brevis were 400 µg/mL and 500 µg/mL, respectively. Only 5 s of contact between water-soluble chitosan and oral bacteria attained at least 99.60% antibacterial activity at a concentration of 500 µg/mL. The water-soluble chitosan-containin g mouthwash significantly demonstrated antibacterial activity that was similar to that of commercial mouthwashes (>99.91%) in both in vitro and in vivo experiments. In addition, the alcohol

  1. Identification, antimicrobial resistance and molecular characterization of the human emerging pathogen Streptococcus gallolyticus subsp. pasteurianus.

    PubMed

    Gherardi, Giovanni; Palmieri, Claudio; Marini, Emanuela; Pompilio, Arianna; Crocetta, Valentina; Di Bonaventura, Giovanni; Creti, Roberta; Facinelli, Bruna

    2016-12-01

    This study aimed to retrospectively identify 22Streptococcus bovis clinical strains based on the new taxonomy, as well as to investigate their antibiotic-resistance and clonality. Strains were identified by Phoenix100 system, 16S rRNA sequencing, and two MALDI-TOF MS platforms (Bruker Biotyper, Vitek MS). Antibiotic resistance was determined both phenotypically and genotypically, and clonality was assessed by PFGE. Most of strains (63.6%) were isolated from urine, and diabetes was the most common underlying disease (31.8%). Phoenix100 system revealed all strains belonged to biotype II, and 16S rRNA sequencing identified all strains as S. gallolyticus subsp pasteurianus (SGSP). Although both MALDI-TOF MS systems correctly identified isolates to the species level, only Bruker Biotyper accurately identified to the subspecies level. Erythromycin-resistant strains (31.8%) were also clindamycin-resistant and positive for erm(B). Strains resistant to tetracycline (68.2%) were also resistant to erythromycin. PFGE showed high genetic variability identifying 17 different pulsotypes, most of which single.

  2. Tex, a putative transcriptional accessory factor, is involved in pathogen fitness in Streptococcus pneumoniae.

    PubMed

    He, Xiangyun; Thornton, Justin; Carmicle-Davis, Stephanie; McDaniel, Larry S

    2006-12-01

    We have identified a pneumococcal gene, tex, which has the potential to regulate gene expression. The tex gene is named for its role in toxin expression in Bordetella pertussis, where it was characterized as an essential gene. Homologous sequences have been found in both Gram-positive and Gram-negative bacteria and are highly conserved at the protein level. Tex family proteins contain a S1 RNA-binding domain at the C-terminus. Members of this family are putative transcriptional accessory factors. Although tex in Streptococcus pneumoniae is homologous to that in B. pertussis, there are distinct differences. Since the tex gene in S. pneumoniae is not an essential gene, we were able to delete tex in strain D39. The tex knockout mutant, DeltaTex, did not affect production of the pneumococcal toxin pneumolysin. However, we observed decreased growth of DeltaTex in the presence of the wild-type strain both in vitro and in vivo as determined by generation numbers and competitive index (CI). The interaction between recombinant Tex and nucleic acids was confirmed by southwestern and northwestern analysis, supporting its role as a transcriptional accessory factor.

  3. The FAD synthetase from the human pathogen Streptococcus pneumoniae: a bifunctional enzyme exhibiting activity-dependent redox requirements.

    PubMed

    Sebastián, María; Lira-Navarrete, Erandi; Serrano, Ana; Marcuello, Carlos; Velázquez-Campoy, Adrián; Lostao, Anabel; Hurtado-Guerrero, Ramón; Medina, Milagros; Martínez-Júlvez, Marta

    2017-08-08

    Prokaryotic bifunctional FAD synthetases (FADSs) catalyze the biosynthesis of FMN and FAD, whereas in eukaryotes two enzymes are required for the same purpose. FMN and FAD are key cofactors to maintain the flavoproteome homeostasis in all type of organisms. Here we shed light to the properties of the hitherto unstudied bacterial FADS from the human pathogen Streptococcus pneumoniae (SpnFADS). As other members of the family, SpnFADS catalyzes the three typical activities of prokaryotic FADSs: riboflavin kinase (RFK), ATP:FMN:adenylyltransferase (FMNAT), and FAD pyrophosphorylase (FADpp). However, several SpnFADS biophysical properties differ from those of other family members. In particular; i) the RFK activity is not inhibited by the riboflavin (RF) substrate, ii) the FMNAT and FADSpp activities require flavin substrates in the reduced state, iii) binding of adenine nucleotide ligands is required for the binding of flavinic substrates/products and iv) the monomer is the preferred state. Collectively, our results add interesting mechanistic differences among the few prokaryotic bifunctional FADSs already characterized, which might reflect the adaptation of the enzyme to relatively different environments. In a health point of view, differences among FADS family members provide us with a framework to design selective compounds targeting these enzymes for the treatment of diverse infectious diseases.

  4. Sequential necrotizing fasciitis caused by the monomicrobial pathogens Streptococcus equisimilis and extended-spectrum beta-lactamase-producing Escherichia coli.

    PubMed

    Endo, Akiko; Matsuoka, Ryosuke; Mizuno, Yasushi; Doi, Asako; Nishioka, Hiroaki

    2016-08-01

    Necrotizing fasciitis is a rapidly progressing bacterial infection of the superficial fascia and subcutaneous tissue that is associated with a high mortality rate and is caused by a single species of bacteria or polymicrobial organisms. Escherichia coli is rarely isolated from patients with monomicrobial disease. Further, there are few reports of extended-spectrum beta-lactamase (ESBL)-producing E. coli associated with necrotizing fasciitis. We report here our treatment of an 85-year-old man who was admitted because of necrotizing fasciitis of his right thigh. Streptococcus equisimilis was detected as a monomicrobial pathogen, and the infection was cured by amputation of the patient's right leg and the administration of antibiotics. However, 5 days after discontinuing antibiotic therapy, he developed necrotizing fasciitis on his right upper limb and died. ESBL-producing E. coli was the only bacterial species isolated from blood and skin cultures. This case demonstrates that ESBL-producing E. coli can cause monomicrobial necrotizing fasciitis, particularly during hospitalization and that a different bacterial species can cause disease shortly after a previous episode.

  5. Protein preparation, crystallization and preliminary X-ray crystallographic analysis of SMU.961 protein from the caries pathogen Streptococcus mutans

    SciTech Connect

    Gao, Xiong-Zhuo; Li, Lan-Fen; Su, Xiao-Dong; Zhao, XiaoJun; Liang, Yu-He

    2007-10-01

    The SMU.961 protein from S. mutans was crystallized and preliminary characterization of the crystals, which diffracted to 2.9 Å resolution, shows them to belong to space group C2. The smu.961 gene encodes a putative protein of 183 residues in Streptococcus mutans, a major pathogen in human dental caries. The gene was cloned into expression vector pET28a and expressed in a substantial quantity in Escherichia coli strain BL21 (DE3) with a His tag at its N-terminus. The recombinant protein SMU.961 was purified to homogeneity in a two-step procedure consisting of Ni{sup 2+}-chelating and size-exclusion chromatography. Crystals suitable for X-ray diffraction were obtained by the hanging-drop vapour-diffusion method and diffracted to 2.9 Å resolution at beamline I911-3, MAX-II-lab, Sweden. The crystal belonged to space group C2, with unit-cell parameters a = 98.62, b = 73.73, c = 184.73 Å, β = 98.82°.

  6. Cloning, characterization and anion inhibition study of a β-class carbonic anhydrase from the caries producing pathogen Streptococcus mutans.

    PubMed

    Dedeoglu, Nurcan; De Luca, Viviana; Isik, Semra; Yildirim, Hatice; Kockar, Feray; Capasso, Clemente; Supuran, Claudiu T

    2015-07-01

    The oral pathogenic bacterium involved in human dental caries formation Streptococcus mutans, encodes for two carbonic anhydrase (CA, EC 4.2.1.1) one belonging to the α- and the other one to the β-class. This last enzyme (SmuCA) has been cloned, characterized and investigated for its inhibition profile with a major class of CA inhibitors, the inorganic anions. Here we show that SmuCA has a good catalytic activity for the CO2 hydration reaction, with kcat 4.2×10(5)s(-1) and kcat/Km of 5.8×10(7)M(-1)×s(-1), being inhibited by cyanate, carbonate, stannate, divannadate and diethyldithiocarbamate in the submillimolar range (KIs of 0.30-0.64mM) and more efficiently by sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid (KIs of 15-46μM). The anion inhibition profile of the S. mutans enzyme is very different from other α- and β-CAs investigated earlier. Identification of effective inhibitors of this new enzyme may lead to pharmacological tools useful for understanding the role of S. mutans CAs in dental caries formation, and eventually the development of pharmacological agents with a new mechanism of antibacterial action.

  7. Multicentric study in five African countries of antibiotic susceptibility for three main pathogens: Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa.

    PubMed

    Zerouali, Khalid; Ramdani-Bouguessa, Nadjia; Boye, Cheikh; Hammami, Adnane

    2016-08-01

    Antibiotic resistance is a growing clinical and epidemiological problem. We report on the antibiotic susceptibility of three pathogens isolated from patients in Algeria, Egypt, Morocco, Senegal, and Tunisia during 2010-2011. In total, 218 Streptococcus pneumoniae, 428 Staphylococcus aureus, and 414 Pseudomonas aeruginosa strains were collected. S. pneumoniae resistance was noted against penicillin (30.2%), erythromycin (27.4%), cefpodoxime (19.1%), amoxicillin (12.0%), cefotaxime (7.4%), and levofloxacin (3.2%). All the strains were teicoplanin susceptible. Staphylococcus aureus methicillin resistance differed between countries, from 5.0% in Senegal to 62.7% in Egypt. Levofloxacin resistance was low in all countries, and the highest rate (in Egypt) was still only 13.6% for intermediate and resistant strains combined. Most strains were susceptible to fosfomycin (99.3%) and pristinamycin (94.2%). P. aeruginosa resistance was found against levofloxacin (30.4%), ciprofloxacin (29.9%), tobramycin (19.7%), ceftazidime (19.2%), and imipenem (17.9%), but not colistin. Antibiotic susceptibility varied widely between countries, with resistance typically most prevalent in Egypt.

  8. Assessing the Metabolic Diversity of Streptococcus from a Protein Domain Point of View

    PubMed Central

    Koehorst, Jasper J.; Martins dos Santos, Vitor A. P.; Schaap, Peter J.

    2015-01-01

    Understanding the diversity and robustness of the metabolism of bacteria is fundamental for understanding how bacteria evolve and adapt to different environments. In this study, we characterised 121 Streptococcus strains and studied metabolic diversity from a protein domain perspective. Metabolic pathways were described in terms of the promiscuity of domains participating in metabolic pathways that were inferred to be functional. Promiscuity was defined by adapting existing measures based on domain abundance and versatility. The approach proved to be successful in capturing bacterial metabolic flexibility and species diversity, indicating that it can be described in terms of reuse and sharing functional domains in different proteins involved in metabolic activity. Additionally, we showed striking differences among metabolic organisation of the pathogenic serotype 2 Streptococcus suis and other strains. PMID:26366735

  9. Adhesion of bacterial pathogens to soil colloidal particles: influences of cell type, natural organic matter, and solution chemistry.

    PubMed

    Zhao, Wenqiang; Walker, Sharon L; Huang, Qiaoyun; Cai, Peng

    2014-04-15

    Bacterial adhesion to granular soil particles is well studied; however, pathogen interactions with naturally occurring colloidal particles (<2 μm) in soil has not been investigated. This study was developed to identify the interaction mechanisms between model bacterial pathogens and soil colloids as a function of cell type, natural organic matter (NOM), and solution chemistry. Specifically, batch adhesion experiments were conducted using NOM-present, NOM-stripped soil colloids, Streptococcus suis SC05 and Escherichia coli WH09 over a wide range of solution pH (4.0-9.0) and ionic strength (IS, 1-100 mM KCl). Cell characterization techniques, Freundlich isotherm, and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (sphere-sphere model) were utilized to quantitatively determine the interactions between cells and colloids. The adhesion coefficients (Kf) of S. suis SC05 to NOM-present and NOM-stripped soil colloids were significantly higher than E. coli WH09, respectively. Similarly, Kf values of S. suis SC05 and E. coli WH09 adhesion to NOM-stripped soil colloids were greater than those colloids with NOM-present, respectively, suggesting NOM inhibits bacterial adhesion. Cell adhesion to soil colloids declined with increasing pH and enhanced with rising IS (1-50 mM). Interaction energy calculations indicate these adhesion trends can be explained by DLVO-type forces, with S. suis SC05 and E. coli WH09 being weakly adhered in shallow secondary energy minima via polymer bridging and charge heterogeneity. S. suis SC05 adhesion decreased at higher IS 100 mM, which is attributed to the change of hydrophobic effect and steric repulsion resulted from the greater presence of extracellular polymeric substances (EPS) on S. suis SC05 surface as compared to E. coli WH09. Hence, pathogen adhesion to the colloidal material is determined by a combination of DLVO, charge heterogeneity, hydrophobic and polymer interactions as a function of solution chemistry.

  10. Development of primer sets for loop-mediated isothermal amplification that enables rapid and specific detection of Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae

    USDA-ARS?s Scientific Manuscript database

    Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae are the three main pathogens causing bovine mastitis, with great losses to the dairy industry. Rapid and specific loop-mediated isothermal amplification methods (LAMP) for identification and differentiation of these three ...

  11. Contribution of the Interaction of Streptococcus mutans Serotype k Strains with Fibrinogen to the Pathogenicity of Infective Endocarditis

    PubMed Central

    Nomura, Ryota; Otsugu, Masatoshi; Naka, Shuhei; Teramoto, Noboru; Kojima, Ayuchi; Muranaka, Yoshinori; Matsumoto-Nakano, Michiyo; Ooshima, Takashi

    2014-01-01

    Streptococcus mutans, a pathogen responsible for dental caries, is occasionally isolated from the blood of patients with bacteremia and infective endocarditis (IE). Our previous study demonstrated that serotype k-specific bacterial DNA is frequently detected in S. mutans-positive heart valve specimens extirpated from IE patients. However, the reason for this frequent detection remains unknown. In the present study, we analyzed the virulence of IE from S. mutans strains, focusing on the characterization of serotype k strains, most of which are positive for the 120-kDa cell surface collagen-binding protein Cbm and negative for the 190-kDa protein antigen (PA) known as SpaP, P1, antigen I/II, and other designations. Fibrinogen-binding assays were performed with 85 clinical strains classified by Cbm and PA expression levels. The Cbm+/PA− group strains had significantly higher fibrinogen-binding rates than the other groups. Analysis of platelet aggregation revealed that SA31, a Cbm+/PA− strain, induced an increased level of aggregation in the presence of fibrinogen, while negligible aggregation was induced by the Cbm-defective isogenic mutant SA31CBD. A rat IE model with an artificial impairment of the aortic valve created using a catheter showed that extirpated heart valves in the SA31 group displayed a prominent vegetation mass not seen in those in the SA31CBD group. These findings could explain why Cbm+/PA− strains are highly virulent and are related to the development of IE, and the findings could also explain the frequent detection of serotype k DNA in S. mutans-positive heart valve clinical specimens. PMID:25287921

  12. First Isolation of Streptococcus halichoeri and Streptococcus phocae from a Steller Sea Lion (Eumetopias jubatus) in South Korea.

    PubMed

    Lee, Kichan; Kim, Ji-Yeon; Jung, Suk Chan; Lee, Hee-Soo; Her, Moon; Chae, Chanhee

    2016-01-01

    Streptococcus species are emerging potential pathogens in marine mammals. We report the isolation and identification of Streptococcus halichoeri and Streptococcus phocae in a Steller sea lion (Eumetopias jubatus) in South Korea.

  13. Genome sequence of Helicobacter suis supports its role in gastric pathology

    PubMed Central

    2011-01-01

    Helicobacter (H.) suis has been associated with chronic gastritis and ulcers of the pars oesophagea in pigs, and with gastritis, peptic ulcer disease and gastric mucosa-associated lymphoid tissue lymphoma in humans. In order to obtain better insight into the genes involved in pathogenicity and in the specific adaptation to the gastric environment of H. suis, a genome analysis was performed of two H. suis strains isolated from the gastric mucosa of swine. Homologs of the vast majority of genes shown to be important for gastric colonization of the human pathogen H. pylori were detected in the H. suis genome. H. suis encodes several putative outer membrane proteins, of which two similar to the H. pylori adhesins HpaA and HorB. H. suis harbours an almost complete comB type IV secretion system and members of the type IV secretion system 3, but lacks most of the genes present in the cag pathogenicity island of H. pylori. Homologs of genes encoding the H. pylori neutrophil-activating protein and γ-glutamyl transpeptidase were identified in H. suis. H. suis also possesses several other presumptive virulence-associated genes, including homologs for mviN, the H. pylori flavodoxin gene, and a homolog of the H. pylori vacuolating cytotoxin A gene. It was concluded that although genes coding for some important virulence factors in H. pylori, such as the cytotoxin-associated protein (CagA), are not detected in the H. suis genome, homologs of other genes associated with colonization and virulence of H. pylori and other bacteria are present. PMID:21414191

  14. Bioethics and cara sui.

    PubMed

    Gillett, Grant

    2005-01-01

    Cara sui (care of the self) is a guiding thread in Foucault's later writings on ethics. Following Foucault in that inquiry, we are urged beyond our fairly superficial conceptions of consequences, harms, benefits, and the rights of persons, and led to examine ourselves and try to articulate the sense of life that animates ethical reasoning. The result is a nuanced understanding with links to virtue ethics and post-modern approaches to ethics and subjectivity. The approach I have articulated draws on the phenomenology of Levinas and Heidegger, the Virtue ethics of Baier, and the post-structuralist writing of Michel Foucault. The subject is seen as negotiable, embodied, provisional and able to be transformed in a way that denies essentialism about human beings, their moral status, and the idea of the good. The human being emerges as responsible because, properly, responsive to the context of discourse in which morality becomes articulated. When we import this style of thinking into bioethics we find that it reaches beyond issues of policy or right conduct and allows us to use the biomedical sciences and the clinical world to revise and interrogate our understanding of ourselves and the theoretical foundations of health care ethics.

  15. Investigation for zoonotic disease pathogens (Aeromonas hydrophila, Pseudomonas fluorescens, Streptococcus iniae) seen in carp farms in Duhok region of Northern Iraq by molecular methods

    NASA Astrophysics Data System (ADS)

    Mohammed, Kamiran Abdulrahman; Arabacı, Muhammed; Önalan, Şükrü

    2017-04-01

    The aim of this study was to determine the zoonotic bacteria in carp farms in Duhok region of the Northern Iraq. Carp is the main fish species cultured in the Duhok region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 20 carp farms in the Duhok Region of the Northern Iraq. Six carp samples were collected from each carp farm. Head kidney tissue samples and intestine tissue samples were collected from each carp sample. Than head kidney and intestine tissue samples were pooled. The total bacterial DNA extraction from the pooled each 20 head kidney tissue samples and pooled each 20 intestinal tissue samples. Primers for pathogens were originally designed from 16S Ribosomal gene region. Zoonotic bacteria were scanned in all tissue samples by absent / present analysis in the RT-PCR. After RT-PCR, Capillary gel electrophoresis bands were used for the confirmation of the size of amplicon which was planned during primer designing stage. As a result, one sample was positive in respect to Aeromonas hydrophila, from intestine and one carp farm was positive in respect to Pseudomonas fluorescens from intestine and two carp farms were positive in respect to Streptococcus iniae. Totally 17 of 20 carp farms were negative in respect to the zoonotic bacteria. In conclusion the zoonotic bacteria were very low (15 %) in carp farms from the Duhok Region in the Northern Iraq. Only in one Carp farms, both Aeromonas hydrophila and Pseudomonas fluorescens were positive. Also Streptococcus inia were positive in two carp farms.

  16. Development and validation of a real-time PCR for Chlamydia suis diagnosis in swine and humans.

    PubMed

    De Puysseleyr, Kristien; De Puysseleyr, Leentje; Geldhof, Julie; Cox, Eric; Vanrompay, Daisy

    2014-01-01

    Pigs are the natural host for Chlamydia suis, a pathogen which is phylogenetically highly related to the human pathogen C. trachomatis. Chlamydia suis infections are generally treated with tetracyclines. In 1998, tetracyline resistant C. suis strains emerged on U.S. pig farms and they are currently present in the Belgian, Cypriote, German, Israeli, Italian and Swiss pig industry. Infections with tetracycline resistant C. suis strains are mainly associated with severe reproductive failure leading to marked economical loss. We developed a sensitive and specific TaqMan probe-based C. suis real-time PCR for examining clinical samples of both pigs and humans. The analytical sensitivity of the real-time PCR is 10 rDNA copies/reaction without cross-amplifying DNA of other Chlamydia species. The PCR was successfully validated using conjunctival, pharyngeal and stool samples of slaughterhouse employees, as well as porcine samples from two farms with evidence of reproductive failure and one farm without clinical disease. Chlamydia suis was only detected in diseased pigs and in the eyes of humans. Positive humans had no clinical complaints. PCR results were confirmed by culture in McCoy cells. In addition, Chlamydia suis isolates were also examined by the tet(C) PCR, designed for demonstrating the tetracycline resistance gene tet(C). The tet(C) gene was only present in porcine C. suis isolates.

  17. Development and Validation of a Real-Time PCR for Chlamydia suis Diagnosis in Swine and Humans

    PubMed Central

    Geldhof, Julie

    2014-01-01

    Pigs are the natural host for Chlamydia suis, a pathogen which is phylogenetically highly related to the human pathogen C. trachomatis. Chlamydia suis infections are generally treated with tetracyclines. In 1998, tetracyline resistant C. suis strains emerged on U.S. pig farms and they are currently present in the Belgian, Cypriote, German, Israeli, Italian and Swiss pig industry. Infections with tetracycline resistant C. suis strains are mainly associated with severe reproductive failure leading to marked economical loss. We developed a sensitive and specific TaqMan probe-based C. suis real-time PCR for examining clinical samples of both pigs and humans. The analytical sensitivity of the real-time PCR is 10 rDNA copies/reaction without cross-amplifying DNA of other Chlamydia species. The PCR was successfully validated using conjunctival, pharyngeal and stool samples of slaughterhouse employees, as well as porcine samples from two farms with evidence of reproductive failure and one farm without clinical disease. Chlamydia suis was only detected in diseased pigs and in the eyes of humans. Positive humans had no clinical complaints. PCR results were confirmed by culture in McCoy cells. In addition, Chlamydia suis isolates were also examined by the tet(C) PCR, designed for demonstrating the tetracycline resistance gene tet(C). The tet(C) gene was only present in porcine C. suis isolates. PMID:24816542

  18. Molecular and antimicrobial susceptibility profiling of atypical Streptococcus species from porcine clinical specimens.

    PubMed

    Moreno, Luisa Z; Matajira, Carlos E C; Gomes, Vasco T M; Silva, Ana Paula S; Mesquita, Renan E; Christ, Ana Paula G; Sato, Maria Inês Z; Moreno, Andrea M

    2016-10-01

    The Streptococcus species present broad phenotypic variation, making identification difficult using only traditional microbiological methods. Even though Streptococcus suis is the most important species for the worldwide swine industry, other Streptococcus species appear to be able to cause disease in swine and could represent a higher underestimated risk for porcine health. The aim of this study was to identify Streptococcus-like isolates by MALDI-TOF MS and 16S rRNA sequencing and further molecular and antibiotic susceptibility characterization of the atypical Streptococcus species capable of causing disease in swine. Fifty presumptive Streptococcus isolates from diseased pigs isolated from different Brazilian States between 2002 and 2014 were evaluated. Among the studied isolates, 26% were identified as Streptococcus hyovaginalis, 24% as Streptococcus plurianimalium, 12% as Streptococcus alactolyticus, 10% as Streptococcus hyointestinalis, and the remaining isolates belonged to Streptococcus henryi (6%), Streptococcus thoraltensis (6%), Streptococcus gallolyticus (6%), Streptococcus gallinaceus (4%), Streptococcus sanguinis (4%), and Streptococcus mitis (2%). The Streptococcus isolates were successfully identified by spectral cluster analysis and 16S rRNA sequencing with 96% of concordance between the techniques. The SE-AFLP analysis also supported Streptococcus species distinction and enabled further observation of higher genetic heterogeneity intra-species. The identified Streptococcus species presented variable MIC values to β-lactams, enrofloxacin and florfenicol, and high resistance rates to tetracyclines and macrolides, which appear to be directly related to the industry's antimicrobial usage and resistance selection. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. In vitro antibacterial activities of ethanol extract of iranian propolis (EEIP) against fish pathogenic bacteria (Aeromonas hydrophila, Yersinia ruckeri & Streptococcus iniae).

    PubMed

    Tukmechi, Amir; Ownagh, Abdolghaffar; Mohebbat, Ali

    2010-10-01

    The "in vitro" antibacterial activity of ethanol extract of propolis (EEIP) from Urmia, Iran was investigated against three prevalent species of fish bacterial pathogens including: Aeromonas hydrophila LMG 3770, Yersinia ruckeri LMG 3279 and Streptococcus iniae LMG 14520. In this study two standard susceptibility testing techniques (Micro-broth dilution method and Agar-well diffusion method) were used to evaluation of the antibacterial activity of EEIP against the mentioned micro-organisms. Also the chemical composition of propolis was determined by the method of Gas chromatography-mass spectrometry (GC-MS). Twenty-six compounds were identified by gas chromatography-mass spectrometry analysis. Results showed Chemical composition of EEIP contained significant amounts of flavonoids, Sesquiterpenes - mainly Eudesmol and Caryophyllene oxide - aromatic acid, and low amounts of aldehydes and triterpens. Furthermore the ethanol extract of propolis inhibited the growth of all examined micro-organisms with the highest antimicrobial activity against Gram-positive bacteria Streptococcus iniae. Ethanol did not influence the antimicrobial effect of EEIP. These antibacterial properties would warrant further studies on the clinical applications of propolis in aquaculture field.

  20. Evolution of the core and pan-genome of Streptococcus: positive selection, recombination, and genome composition

    PubMed Central

    Lefébure, Tristan; Stanhope, Michael J

    2007-01-01

    Background The genus Streptococcus is one of the most diverse and important human and agricultural pathogens. This study employs comparative evolutionary analyses of 26 Streptococcus genomes to yield an improved understanding of the relative roles of recombination and positive selection in pathogen adaptation to their hosts. Results Streptococcus genomes exhibit extreme levels of evolutionary plasticity, with high levels of gene gain and loss during species and strain evolution. S. agalactiae has a large pan-genome, with little recombination in its core-genome, while S. pyogenes has a smaller pan-genome and much more recombination of its core-genome, perhaps reflecting the greater habitat, and gene pool, diversity for S. agalactiae compared to S. pyogenes. Core-genome recombination was evident in all lineages (18% to 37% of the core-genome judged to be recombinant), while positive selection was mainly observed during species differentiation (from 11% to 34% of the core-genome). Positive selection pressure was unevenly distributed across lineages and biochemical main role categories. S. suis was the lineage with the greatest level of positive selection pressure, the largest number of unique loci selected, and the largest amount of gene gain and loss. Conclusion Recombination is an important evolutionary force in shaping Streptococcus genomes, not only in the acquisition of significant portions of the genome as lineage specific loci, but also in facilitating rapid evolution of the core-genome. Positive selection, although undoubtedly a slower process, has nonetheless played an important role in adaptation of the core-genome of different Streptococcus species to different hosts. PMID:17475002

  1. Natural Variation in the Promoter of the Gene Encoding the Mga Regulator Alters Host-Pathogen Interactions in Group A Streptococcus Carrier Strains

    PubMed Central

    Flores, Anthony R.; Olsen, Randall J.; Wunsche, Andrea; Kumaraswami, Muthiah; Shelburne, Samuel A.; Carroll, Ronan K.

    2013-01-01

    Humans commonly carry pathogenic bacteria asymptomatically, but the molecular factors underlying microbial asymptomatic carriage are poorly understood. We previously reported that two epidemiologically unassociated serotype M3 group A Streptococcus (GAS) carrier strains had an identical 12-bp deletion in the promoter of the gene encoding Mga, a global positive gene regulator. Herein, we report on studies designed to test the hypothesis that the identified 12-bp deletion in the mga promoter alters GAS virulence, thereby potentially contributing to the asymptomatic carrier phenotype. Using allelic exchange, we introduced the variant promoter into a serotype M3 invasive strain and the wild-type promoter into an asymptomatic carrier strain. Compared to strains with the wild-type mga promoter, we discovered that strains containing the promoter with the 12-bp deletion produced significantly fewer mga and Mga-regulated gene transcripts. Consistent with decreased mga transcripts, strains containing the variant mga promoter were also significantly less virulent in in vivo and ex vivo models of GAS disease. Further, we provide evidence that the pleiotropic regulator protein CodY binds to the mga promoter and that the 12-bp deletion in the mga promoter reduces CodY-mediated mga transcription. We conclude that the naturally occurring 12-bp deletion in the mga promoter significantly alters the pathogen-host interaction of these asymptomatic carrier strains. Our findings provide new insight into the molecular basis of the carrier state of an important human pathogen. PMID:23980109

  2. Assessment of Cpa, Scl1 and Scl2 in clinical group A streptococcus isolates and patients from north India: an evaluation of the host pathogen interaction.

    PubMed

    Chaudhary, Priyanka; Kumar, Rajesh; Sagar, Vivek; Sarkar, Subendu; Singh, Rupneet; Ghosh, Sujata; Singh, Surjit; Chakraborti, Anuradha

    2017-09-30

    Group A streptococcus (GAS) infection remains a major concern due to multiple diseases including pharyngitis, impetigo, acute rheumatic fever (ARF) and rheumatic heart disease (RHD). It uses different adhesins and virulence factors like Cpa (collagen binding protein) and Scl (collagen-like protein) in its pathogenicity. Scl having similarities with human collagen may contribute to inducing autoimmunity in the host. Here we assessed gene expression, antibody titer of Cpa, Scl1 and Scl2 in both clinical GAS isolates (n=45) and blood (n=45) obtained from pharyngisis, ARF (acute rheumatic fever) and RHD respectively. Skin isolates (n=30) were obtained from impetigo patients. The study revealed a total of 27 GAS emm types. Frequency of cpa, scl1, scl2 was high in ARF isolates. The antibody titer of these proteins was high in all isolates, and also in patients with pharyngitis and ARF. All isolates showed high binding affinity toward collagen I and IV, which further indicates a potential host pathogen interaction. Our study reflects a strong association of Cpa and Scls in early and post-GAS pathogenicity. However, the increased antibody titer of Scl1 and Scl2 during ARF may be attributed to a cogent immune response in the host. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  3. Comparative genome analysis identifies two large deletions in the genome of highly-passaged attenuated Streptococcus agalactiae strain YM001 compared to the parental pathogenic strain HN016.

    PubMed

    Wang, Rui; Li, Liping; Huang, Yan; Luo, Fuguang; Liang, Wanwen; Gan, Xi; Huang, Ting; Lei, Aiying; Chen, Ming; Chen, Lianfu

    2015-11-04

    Streptococcus agalactiae (S. agalactiae), also known as group B Streptococcus (GBS), is an important pathogen for neonatal pneumonia, meningitis, bovine mastitis, and fish meningoencephalitis. The global outbreaks of Streptococcus disease in tilapia cause huge economic losses and threaten human food hygiene safety as well. To investigate the mechanism of S. agalactiae pathogenesis in tilapia and develop attenuated S. agalactiae vaccine, this study sequenced and comparatively analyzed the whole genomes of virulent wild-type S. agalactiae strain HN016 and its highly-passaged attenuated strain YM001 derived from tilapia. We performed Illumina sequencing of DNA prepared from strain HN016 and YM001. Sequencedreads were assembled and nucleotide comparisons, single nucleotide polymorphism (SNP) , indels were analyzed between the draft genomes of HN016 and YM001. Clustered regularly interspaced short palindromic repeats (CRISPRs) and prophage were detected and analyzed in different S. agalactiae strains. The genome of S. agalactiae YM001 was 2,047,957 bp with a GC content of 35.61 %; it contained 2044 genes and 88 RNAs. Meanwhile, the genome of S. agalactiae HN016 was 2,064,722 bp with a GC content of 35.66 %; it had 2063 genes and 101 RNAs. Comparative genome analysis indicated that compared with HN016, YM001 genome had two significant large deletions, at the sizes of 5832 and 11,116 bp respectively, resulting in the deletion of three rRNA and ten tRNA genes, as well as the deletion and functional damage of ten genes related to metabolism, transport, growth, anti-stress, etc. Besides these two large deletions, other ten deletions and 28 single nucleotide variations (SNVs) were also identified, mainly affecting the metabolism- and growth-related genes. The genome of attenuated S. agalactiae YM001 showed significant variations, resulting in the deletion of 10 functional genes, compared to the parental pathogenic strain HN016. The deleted and mutated functional genes all

  4. Porcine retinal cell line VIDO R1 and Chlamydia suis to modelize ocular chlamydiosis.

    PubMed

    Käser, Tobias; Cnudde, Thomas; Hamonic, Glenn; Rieder, Meghanne; Pasternak, J Alex; Lai, Ken; Tikoo, Suresh K; Wilson, Heather L; Meurens, François

    2015-08-15

    Human ocular Chlamydia trachomatis infections can lead to trachoma, the major cause of infectious blindness worldwide. Trachoma control strategies are very helpful but logistically challenging, and a trachoma vaccine is needed but not available. Pigs are a valuable large animal model for various immunological questions and could facilitate the study of human ocular chlamydial infections. In addition, a recent study identified the zoonotic potential of Chlamydia suis, the natural pathogen of pigs. In terms of the One Health Initiative, understanding the host-pathogen-interactions and finding a vaccine for porcine chlamydia infections would also benefit human health. Thus, we infected the porcine retinal cell line VIDO R1 with C. suis and analyzed the chlamydial life cycle and the innate immune response of the infected cells. Our results indicate that C. suis completes its life cycle in VIDO R1 cells within 48 h, comparable to C. trachomatis in humans. C. suis infection of VIDO R1 cells led to increased levels of various innate immune mediators like pathogen recognition receptors, cytokines and chemokines including IL6, TNFα, and MMP9, also most relevant in human C. trachomatis infections. These results illustrate the first steps in the host-pathogen-interactions of ocular C. suis infections in pigs and show their similarity to C. trachomatis infections in humans, justifying further testing of pigs as an animal model for human trachoma. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Effects of the ERES pathogenicity region regulator Ralp3 on Streptococcus pyogenes serotype M49 virulence factor expression.

    PubMed

    Siemens, Nikolai; Fiedler, Tomas; Normann, Jana; Klein, Johannes; Münch, Richard; Patenge, Nadja; Kreikemeyer, Bernd

    2012-07-01

    Streptococcus pyogenes (group A streptococcus [GAS]) is a highly virulent Gram-positive bacterium. For successful infection, GAS expresses many virulence factors, which are clustered together with transcriptional regulators in distinct genomic regions. Ralp3 is a central regulator of the ERES region. In this study, we investigated the role of Ralp3 in GAS M49 pathogenesis. The inactivation of Ralp3 resulted in reduced attachment to and internalization into human keratinocytes. The Δralp3 mutant failed to survive in human blood and serum, and the hyaluronic acid capsule was slightly decreased. In addition, the mutant showed a lower binding capacity to human plasminogen, and the SpeB activity was significantly decreased. Complementation of the Δralp3 mutant restored the wild-type phenotype. The transcriptome and quantitative reverse transcription-PCR analysis of the serotype M49 GAS strain and its isogenic Δralp3 mutant identified 16 genes as upregulated, and 43 genes were found to be downregulated. Among the downregulated genes, there were open reading frames encoding proteins involved in metabolism (e.g., both lac operons and the fru operon), genes encoding lantibiotics (e.g., the putative salivaricin operon), and ORFs encoding virulence factors (such as the whole Mga core regulon and further genes under Mga control). In summary, the ERES region regulator Ralp3 is an important serotype-specific transcriptional regulator for virulence and metabolic control.

  6. An in silico model for identification of small RNAs in whole bacterial genomes: characterization of antisense RNAs in pathogenic Escherichia coli and Streptococcus agalactiae strains

    PubMed Central

    Pichon, Christophe; du Merle, Laurence; Caliot, Marie Elise; Trieu-Cuot, Patrick; Le Bouguénec, Chantal

    2012-01-01

    Characterization of small non-coding ribonucleic acids (sRNA) among the large volume of data generated by high-throughput RNA-seq or tiling microarray analyses remains a challenge. Thus, there is still a need for accurate in silico prediction methods to identify sRNAs within a given bacterial species. After years of effort, dedicated software were developed based on comparative genomic analyses or mathematical/statistical models. Although these genomic analyses enabled sRNAs in intergenic regions to be efficiently identified, they all failed to predict antisense sRNA genes (asRNA), i.e. RNA genes located on the DNA strand complementary to that which encodes the protein. The statistical models enabled any genomic region to be analyzed theorically but not efficiently. We present a new model for in silico identification of sRNA and asRNA candidates within an entire bacterial genome. This model was successfully used to analyze the Gram-negative Escherichia coli and Gram-positive Streptococcus agalactiae. In both bacteria, numerous asRNAs are transcribed from the complementary strand of genes located in pathogenicity islands, strongly suggesting that these asRNAs are regulators of the virulence expression. In particular, we characterized an asRNA that acted as an enhancer-like regulator of the type 1 fimbriae production involved in the virulence of extra-intestinal pathogenic E. coli. PMID:22139924

  7. Increased pilus production conferred by a naturally occurring mutation alters host-pathogen interaction in favor of carriage in Streptococcus pyogenes.

    PubMed

    Flores, Anthony R; Olsen, Randall J; Cantu, Concepcion; Pallister, Kyler B; Guerra, Fermin E; Voyich, Jovanka M; Musser, James M

    2017-03-06

    Studies of the human pathogen group A Streptococcus (GAS) define the carrier phenotype as increased ability to adhere to and persist on epithelial surfaces and decreased ability to cause disease. We tested the hypothesis that a single amino acid change (Arg135Gly) in a highly conserved sensor kinase (LiaS) of a poorly defined GAS regulatory system contributes to a carrier phenotype through increased pilus production. When introduced into an emm serotype-matched invasive strain, the carrier allele (liaS(R135G)) recapitulated a carrier phenotype defined by increased ability to adhere to mucosal surfaces and decreased ability to cause disease. Gene transcript analyses revealed that the liaS mutation significantly altered transcription of the genes encoding pilus when in the presence of bacitracin. Elimination of pilus production in the isogenic carrier mutant decreased ability to colonize the mouse nasopharynx, adhere to and be internalized by cultured human epithelial cells, and restored a virulence phenotype in a mouse model of necrotizing fasciitis. We also observed significantly reduced survival of the isogenic carrier mutant compared to the parental invasive strain after exposure to human neutrophils. Elimination of pilus in the isogenic carrier mutant increased neutrophil survival to the parental invasive strain level. Together, our data demonstrate that the carrier mutation (liaS(R135G)) affects pilus expression. Our data suggest new mechanisms of pilus gene regulation in GAS and differs from the enhanced invasiveness associated with increased pilus production in other bacterial pathogens.

  8. Effects of antimicrobial peptide L-K6, a temporin-1CEb analog on oral pathogen growth, Streptococcus mutans biofilm formation, and anti-inflammatory activity.

    PubMed

    Shang, Dejing; Liang, Hao; Wei, Shi; Yan, Xin; Yang, Qingzu; Sun, Yue

    2014-10-01

    Dental caries and periodontitis are common bacterial mouth infections. As a potentially attractive substitute for conventional antibiotics, antimicrobial peptides have been widely tested and used for controlling bacterial infections. In this study, we tested the efficacy of the peptides from the skin secretions of Rana chensinensis for killing several major cariogenic and periodontic pathogens as well as Candida albicans. L-K6, a temporin-1CEb analog, exhibited high antimicrobial activity against the tested oral pathogens and was able to inhibit Streptococcus mutans biofilm formation and reduce 1-day-old S. mutans biofilms with a minimum biofilm inhibitory concentration and reducing concentration of 3.13 and 6.25 μM, respectively. The results of confocal laser scanning microscopy demonstrated that the peptide significantly reduced cell viability within oral biofilms. Furthermore, as little as 5 μM L-K6 significantly inhibited lipopolysaccharide (LPS)- and interleukin-1β-induced productions of interleukin-8 and tumor necrosis factor-α from THP-1 monocytic cells. This anti-inflammatory activity is associated with the binding of L-K6 to LPS and neutralizing LPS-induced proinflammatory responses in THP-1 cells, as well as dissociating LPS aggregates. Our results suggest that L-K6 may have potential clinical applications in treating dental caries by killing S. mutans within dental plaque and acting as anti-inflammatory agents in infected tissues.

  9. Metalloproteases secreted by Actinobacillus suis.

    PubMed

    Negrete-Abascal, Erasmo; Pacheco, Sergio Vaca; Paniagua, Gloria L; Méndez, Alma Pérez; Caballero, Jorge Ibarra; Márquez, Víctor M Pérez; Tenorio, Víctor R

    2004-07-01

    Actinobacillus suis secretes metalloproteases into its medium. These secreted proteins, when concentrated by precipitation with 70% (NH4)2SO4 or methanol, displayed proteolytic activity at >200 kDa molecular mass bands in 10% polyacrylamide gels copolymerized with bovine casein (1%). They showed activity in a broad pH range (from pH 5 to pH 10) and were inhibited by 20 mM EDTA or EGTA, but could be reactivated by calcium. They were found heat stable at 40 degrees C, 50 degrees C, 60 degrees C, and 70 degrees C, but their activity diminished at 80 degrees C or higher. They degraded pig and bovine IgG and cross-reacted with a polyclonal serum against a high molecular mass secreted protease from A. pleuropneumoniae. Extracellular proteases could play a role in diseases caused by A. suis.

  10. Comparative activity of garenoxacin and other agents by susceptibility and time-kill testing against Staphylococcus aureus, Streptococcus pyogenes and respiratory pathogens.

    PubMed

    Noviello, Silvana; Ianniello, Filomena; Leone, Sebastiano; Esposito, Silvano

    2003-11-01

    Garenoxacin is a novel des-F(6)quinolone that has shown excellent antimicrobial activity against a wide range of clinically important microorganisms. In this study, its activity was examined, in comparison with that of other antimicrobial agents, by susceptibility and time-kill testing against Staphylococcus aureus, Streptococcus pyogenes and respiratory pathogens. Overall, 200 bacterial strains were tested. The antimicrobial activity of garenoxacin was compared with that of ciprofloxacin, levofloxacin, moxifloxacin, amoxicillin, co-amoxiclav, cefuroxime, cefotaxime, ceftriaxone, imipenem, erythromycin and clarithromycin. In addition, the bactericidal activity of garenoxacin, moxifloxacin, levofloxacin and ciprofloxacin was evaluated by time-kill analysis against four strains each of staphylococci [two methicillin-susceptible (MSSA) and two methicillin-resistant (MRSA)], pneumococci (two penicillin-susceptible and two penicillin-resistant) and Streptococcus pyogenes (two erythromycin-susceptible and two erythromycin-resistant). Antibiotics were tested at concentrations 1-8 x MIC. MIC90 values of garenoxacin for the MSSA and MRSA strains were 0.03 and 2 mg/L, respectively. Among all the quinolones tested, garenoxacin yielded the lowest MIC values against all pneumococci (MIC90 0.12 mg/L) irrespective of macrolide resistance; the rank order of activity was garenoxacin> moxifloxacin>levofloxacin>ciprofloxacin. Excellent activity was shown also against Haemophilus influenzae (MIC90 or= 3 log10 decrease in viable counts (cfu/mL) within 3 h at 4 x MIC, whereas a moderate, slower killing rate was observed versus streptococci. This investigational des-F(6)quinolone represents a

  11. Investigation of zoonotic disease pathogens (Aeromonas hydrophila, Pseudomonas fluorescens, Streptococcus iniae) seen in carp farms in the Northern Iraq-Erbil region by molecular methods

    NASA Astrophysics Data System (ADS)

    Ibraheem, Azad Saber; Önalan, Şükrü; Arabacı, Muhammed

    2017-04-01

    The aim of this study was to determine the zoonotic bacteria in carp farms in the Northern Iraq-Erbil region. Carp is the main fish species cultured in Erbil region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 25 carp farms in the Northern Iraq-Erbil region. Six carp samples were collected from each carp farm. Head kidney and intestine tissue samples were collected from each carp sample. Then head kidney and intestine tissue samples were pooled separately from each carp farm. Total bacterial DNA had been extracted from the 25 pooled head kidney and 25 intestinal tissue samples. The pathogen Primers were originally designed from 16S RNA gene region. Zoonotic bacteria were scanned in all tissue samples with absent/present analysis by RT-PCR. Furthermore, the capillary gel electrophoresis bands were used for confirmation of amplicon size which was planned during primer designing stage. As a result, thirteen carp farms were positive in the respect to Aeromonas hydrophila, eight carp farms were positive from head kidney and six carp farms were positive from the intestine, only one carp farm was positive from both head kidney and the intestine tissue samples. In the respect to Streptococcus iniae, four carp farms were positive from head kidney and two carp farms were positive from the intestine. Only one carp farm was positive in the respect to Pseudomonas fluorescens from the intestine. Totally, 9 of 25 carp farms were cleared (negative) the zoonotic bacteria. In conclusion, the zoonotic bacteria were high (64 %) in carp farms in the Northern Iraq-Erbil region.

  12. Updating the proteome of the uncultivable hemotrophic Mycoplasma suis in experimentally infected pigs.

    PubMed

    Dietz, Stefanie; Lassek, Christian; Mack, Sarah-Lena; Ritzmann, Mathias; Stadler, Julia; Becher, Dörte; Hoelzle, Katharina; Riedel, Katharina; Hoelzle, Ludwig E

    2016-02-01

    Mycoplasma suis belongs to the hemotrophic mycoplasmas that are associated with acute and chronic anemia in a wide range of livestock and wild animals. The inability to culture M. suis in vitro has hindered its characterization at the molecular level. Since the publication of M. suis genome sequences in 2011 only one proteome study has been published. Aim of the presented study was to significantly extend the proteome coverage of M. suis strain KI_3806 during acute infection by applying three different protein extraction methods followed by 1D SDS-PAGE and LC-MS/MS. A total of 404 of 795 M. suis KI_3806 proteins (50.8%) were identified. Data analysis revealed the expression of 83.7% of the predicted ORFs with assigned functions but also highlights the expression of 179 of 523 (34.2%) hypothetical proteins with unknown functions. Computational analyses identified expressed membrane-associated hypothetical proteins that might be involved in adhesion or host-pathogen interaction. Furthermore, analyses of the expressed proteins indicated the existence of a hexose-6-phosphate-transporter and an ECF transporter. In conclusion, our proteome study provides a further step toward the elucidation of the unique life cycle of M. suis and the establishment of an in vitro culture. All MS data have been deposited in the ProteomeXchange with identifier PXD002294 (http://proteomecentral.proteomexchange.org/dataset/PXD002294).

  13. Brucella suis vaccine strain S2-infected immortalized caprine endometrial epithelial cell lines induce non-apoptotic ER-stress.

    PubMed

    Wang, Xiangguo; Lin, Pengfei; Yin, Yanlong; Zhou, Jinhua; Lei, Lanjie; Zhou, Xudong; Jin, Yaping; Wang, Aihua

    2015-05-01

    Brucella, which is regarded as an intracellular pathogen responsible for a zoonotic disease called brucellosis, survives and proliferates within several types of phagocytic and non-phagocytic cells. Brucella infects not only their preferred hosts but also other domestic and wild animal species, inducing abortion and infertility. Therefore, the interaction between uterine cells and Brucella is important for understanding the pathogenesis of this disease. In this study, we describe the Brucella suis vaccine strain S2 (B.suis.S2) infection and replication in the immortalized caprine endometrial epithelial cell line hTERT-EECs and the induced cellular and molecular response modulation in vitro. We found that B.suis S2 was able to infect and replicate to high titers and inhibit the proliferation of EECs and induce non-apoptotic pathways, as determined by B.suis.S2 detection using MTT and acridine orange/ethidium bromide (AO/EB) staining and flow cytometry. We explored the evidence of non-apoptotic pathways using real-time quantitative RT-PCR and by western blot analysis. Finally, we discovered the over-expression of GRP78, ATF4, ATF6, PERK, eIF2α, CHOP, and cytochrome c (Cyt-c) but not IRE1, xbp-1, and caspase-3 in B.suis.S2 (HK)-attacked and B.suis.S2-infected cells, suggesting that the molecular mechanism of ER stress sensor activation by B.suis.S2 is basically concomitant with that by B.suis.S2 (HK) and that ER stress, especially the PERK pathway, plays an important role in the process of B.suis.S2 infecting EEC, which may, in part, explain the role of the uterus in the pathogenesis of B.suis.S2.

  14. The specificity of oligopeptide transport by Streptococcus thermophilus resembles that of Lactococcus lactis and not that of pathogenic streptococci.

    PubMed

    Juille, Odile; Le Bars, Dominique; Juillard, Vincent

    2005-06-01

    Peptide transport is a crucial step in the growth of Streptococcus thermophilus in protein- or peptide-containing media. The objective of the present work was to determine the specificity of peptide utilization by this widely used lactic acid bacterium. To reach that goal, complementary approaches were employed. The capability of a proteinase-negative S. thermophilus strain to grow in a chemically defined medium containing a mixture of peptides isolated from milk as the source of amino acids was analysed. Peptides were separated into three size classes by ultrafiltration. The strain was able to use peptides up to 3.5 kDa during growth, as revealed by liquid chromatography and mass spectrometry analyses. The same strain was grown in chemically defined medium containing a tryptic digest of casein, and the respective time-course consumption of the peptides during growth was estimated. The ability to consume large peptides (up to 23 residues) was confirmed, as long as they are cationic and hydrophobic. These results were confirmed by peptide transport studies. Extension of the study to 11 other strains revealed that they all shared these preferences.

  15. Preparation and evaluation of antimicrobial activity of nanosystems for the control of oral pathogens Streptococcus mutans and Candida albicans

    PubMed Central

    Pupe, Carolina Gonçalves; Villardi, Michele; Rodrigues, Carlos Rangel; Rocha, Helvécio Vinícius Antunes; Maia, Lucianne Cople; de Sousa, Valeria Pereira; Cabral, Lucio Mendes

    2011-01-01

    Background Diseases that affect the buccal cavity are a public health concern nowadays. Chlorhexidine and nystatin are the most commonly used drugs for the control of buccal affections. In the search for more effective antimicrobials, nanotechnology can be successfully used to improve the physical chemical properties of drugs whilst avoiding the undesirable side effects associated with its use. Herein described are studies using nystatin and chlorhexidine with sodium montmorillonite (MMTNa), and chlorhexidine with β-cyclodextrin and two derivatives methyl-β-cyclodextrin and hydroxypropyl-β-cyclodextrin in the development of antimicrobial nanosystems. Methods The nanosystems were prepared by kneading and solubilization followed by freeze-drying technique. The nanosystems were characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Nanosystem antimicrobial activity against Streptococcus mutans and Candida albicans strains was evaluated with inhibition halo analysis. Results The nanocarriers MMTNa and cyclodextrins showed good yields. XRPD, FTIR, and DSC analysis confirmed the proposed nanosystems formation and the suitability of the production methods. The nanosystems that showed best antimicrobial effect were chlorhexidine gluconate (CHX) and cyclodextrin inclusion complexes and CHX:MMTNa 60% cation exchange capacity – 24 hours. Conclusion The nanosystem formulations present higher stability for all chlorhexidine inclusion complexes compared with pure chlorhexidine. The nystatin nanosystems have the potential to mask the bitter taste, justifying subsequent in-vivo studies. For these reasons, further studies are being carried out to evaluate their application in professional formulations. PMID:22114490

  16. Bacteria-induced egg hatching differs for Trichuris muris and Trichuris suis.

    PubMed

    Vejzagić, Nermina; Adelfio, Roberto; Keiser, Jennifer; Kringel, Helene; Thamsborg, Stig Milan; Kapel, Christian M O

    2015-07-15

    Eggs of the porcine whipworm Trichuris suis are currently explored in human clinical trials as a treatment of immune-mediated diseases. In this context, only the infective, embryonated eggs, constitute the Active Pharmaceutical Ingredient (API). The rodent whipworm, Trichuris muris is commonly used as a laboratory model to study Trichuris biology. The embryonated eggs (containing a fully developed larva) are biologically active and will invade the large intestinal mucosa of the host. This study aims to assess the in vitro hatching of T. muris and T. suis eggs in various bacterial cultures as a measure for their biological activity. Eggs of T. muris and T. suis were incubated with Escherichia coli strain (BL-21) at three concentrations in a slightly modified in vitro egg hatching assay previously developed for T. muris. Additionally, E. coli strains (M15, SG13009, PMC103, JM109, TUNER, DH5alpha, TOP10) and five Gram-positive bacteria (Enterococcus caccae, Streptococcus hyointestinalis, Lactobacillus amylovorus, L. murinus, and L. reuteri) were tested as a hatching stimulus for T. muris and T. suis eggs. Whereas T. muris eggs hatched, T. suis did not, even when exposed to different concentrations and strains of E. coli after 4 and 24-hour incubation. When incubated with Gram-positive bacteria, only T. muris eggs showed noticeable hatching after 20 h, although with high variability. The observed difference in hatching of T. muris and T. suis eggs incubated with selected bacteria, indicate significant biological differences which may reflect specific adaptation to different host-specific gut microbiota.

  17. Complete Genome Sequence of Mycoplasma suis and Insights into Its Biology and Adaption to an Erythrocyte Niche

    PubMed Central

    Guimaraes, Ana M. S.; Santos, Andrea P.; SanMiguel, Phillip; Walter, Thomas; Timenetsky, Jorge; Messick, Joanne B.

    2011-01-01

    Mycoplasma suis, the causative agent of porcine infectious anemia, has never been cultured in vitro and mechanisms by which it causes disease are poorly understood. Thus, the objective herein was to use whole genome sequencing and analysis of M. suis to define pathogenicity mechanisms and biochemical pathways. M. suis was harvested from the blood of an experimentally infected pig. Following DNA extraction and construction of a paired end library, whole-genome sequencing was performed using GS-FLX (454) and Titanium chemistry. Reads on paired-end constructs were assembled using GS De Novo Assembler and gaps closed by primer walking; assembly was validated by PFGE. Glimmer and Manatee Annotation Engine were used to predict and annotate protein-coding sequences (CDS). The M. suis genome consists of a single, 742,431 bp chromosome with low G+C content of 31.1%. A total of 844 CDS, 3 single copies, unlinked rRNA genes and 32 tRNAs were identified. Gene homologies and GC skew graph show that M. suis has a typical Mollicutes oriC. The predicted metabolic pathway is concise, showing evidence of adaptation to blood environment. M. suis is a glycolytic species, obtaining energy through sugars fermentation and ATP-synthase. The pentose-phosphate pathway, metabolism of cofactors and vitamins, pyruvate dehydrogenase and NAD+ kinase are missing. Thus, ribose, NADH, NADPH and coenzyme A are possibly essential for its growth. M. suis can generate purines from hypoxanthine, which is secreted by RBCs, and cytidine nucleotides from uracil. Toxins orthologs were not identified. We suggest that M. suis may cause disease by scavenging and competing for host' nutrients, leading to decreased life-span of RBCs. In summary, genome analysis shows that M. suis is dependent on host cell metabolism and this characteristic is likely to be linked to its pathogenicity. The prediction of essential nutrients will aid the development of in vitro cultivation systems. PMID:21573007

  18. First report of molecular identification of Cystoisospora suis in piglets with lethal diarrhea in Japan.

    PubMed

    Matsubayashi, Makoto; Takayama, Hideko; Kusumoto, Masahiro; Murata, Misato; Uchiyama, Yuka; Kaji, Masaya; Sasai, Kazumi; Yamaguchi, Ryosaku; Shibahara, Tomoyuki

    2016-03-01

    Cystoisospora suis is a pathogen that causes diarrhea in pigs and can lead to serious disease. Species identification, especially by histopathological examination, is often difficult because of morphologically similar parasites such as Eimeria species. In this study, we used histopathological, bacteriological, virological, and parasitological methods to identify the cause of the disease in two piglets with severe diarrhea. Villous atrophy, diffuse necrosis, and flattening of mucosal epithelial cells were found in the ilea of examined piglets, and coccidian parasites were found in the cytoplasm of the epithelial cells. In some merozoites in the meronts, the presence of two nuclei indicated type 1 merozoites, characteristic of C. suis. According to Cystoisospora-specific PCR targeting the rRNA internal transcribed spacer 1 (ITS1) gene, the sequences of the products were 98.5% similar to those of C. suis. Escherichia coli (O149 serogroup) exhibiting a virulence factor profile (LT, STb, and EAST1 as toxins and F4 as a colonization factor) was detected in one piglet. No other bacteria or significant enteric viruses were found. Co-infection with C. suis and E. coli could imply aggravation of the disease, although further study is needed to assess the pathogenicity of this interaction. This study is the first to clarify by molecular analysis the sequences of C. suis detected in piglets in Japan.

  19. Increasing of temperature induces pathogenicity of Streptococcus agalactiae and the up-regulation of inflammatory related genes in infected Nile tilapia (Oreochromis niloticus).

    PubMed

    Kayansamruaj, Pattanapon; Pirarat, Nopadon; Hirono, Ikuo; Rodkhum, Channarong

    2014-08-06

    Temperature strongly affects the health of aquatic poikilotherms. In Nile tilapia (Oreochromis niloticus), elevated water temperatures increase the severity of streptococcosis. Here we investigated the effects of temperature on the vulnerability and inflammatory response of Nile tilapia to Streptococcus agalactiae (Group B streptococci; GBS). At 35 and 28 °C, GBS took 4 and 7h, respectively to reach the log-phase and, when incubated with tilapia whole blood, experienced survival rates of 97% and 2%, respectively. The hemolysis activity of GBS grown at 35 °C was five times higher than that of GBS grown at 28 °C. GBS expressed cylE (β-hemolysin/cytolysin), cfb (CAMP factor) and PI-2b (pili-backbone) much more strongly at 35 °C than at 28 °C. Challenging Nile tilapia reared at 35 and 28 °C with GBS resulted in accumulated mortalities of about 85% and 45%, respectively. At 35 °C, infected tilapia exhibited tremendous inflammatory responses due to a dramatic up-regulation (30-40-fold) of inflammatory-related genes (cyclooxygenase-2, IL-1β and TNF-α) between 6 and 96 h-post infection. These results suggest that the increase of GBS pathogenicity to Nile tilapia induced by elevated temperature is associated with massive inflammatory responses, which may lead to acute mortality.

  20. Rapid Assessment of Resistance to Antibiotic Inhibitors of Protein Synthesis in the Gram-Positive Pathogens, Enterococcus faecalis and Streptococcus pneumoniae, Based on Evaluation of the Lytic Response.

    PubMed

    Otero, Fátima; Tamayo, María; Santiso, Rebeca; Gosálvez, Jaime; Bou, Germán; Fernández, José Luis

    2017-04-01

    A novel assay for rapid determination of resistance to antibiotic inhibitors of protein synthesis was developed for the gram-positive pathogens, Enterococcus faecalis and Streptococcus pneumoniae. To this purpose, a lytic response was obtained by a brief incubation with lysozyme or a mixture of lysozyme, Triton X-100, and EDTA for E. faecalis (n = 82) and S. pneumoniae (n = 51), respectively. Lysis was quantified by visualizing the released nucleoids. Antibiotic-susceptible bacteria treated with Clinical and Laboratory Standards Institute (CLSI) breakpoint doses of erythromycin, azithromycin, or doxycycline that inhibited protein synthesis demonstrated a large reduction of lysed cells with respect to the control, that is, without antibiotics. However, cell lysis prevention was much lower in nonsusceptible strains, with unsuccessful inhibition of protein synthesis. ROC analysis showed that a reduction value of ≥35.6% and ≥40.4% discriminates susceptible and nonsusceptible strains for erythromycin and for doxycycline, respectively, in E. faecalis, whereas ≥20.0% is adequate for both macrolides and doxycycline in S. pneumoniae. Resistant stains were identified in 90-120 min with sensitivity and specificity between 91.7% and 100%. This is a proof of concept that evaluation of the lytic response may be a rapid and efficient test for determination of resistance to antibiotic inhibitors of protein synthesis.

  1. Transduction of the Streptococcus pyogenes bacteriophage Φm46.1, carrying resistance genes mef(A) and tet(O), to other Streptococcus species.

    PubMed

    Giovanetti, Eleonora; Brenciani, Andrea; Morroni, Gianluca; Tiberi, Erika; Pasquaroli, Sonia; Mingoia, Marina; Varaldo, Pietro E

    2014-01-01

    Φm46.1 - Streptococcus pyogenes bacteriophage carrying mef(A) and tet(O), respectively, encoding resistance to macrolides (M phenotype) and tetracycline - is widespread in S. pyogenes but has not been reported outside this species. Φm46.1 is transferable in vitro among S. pyogenes isolates, but no information is available about its transferability to other Streptococcus species. We thus investigated Φm46.1 for its ability to be transduced in vitro to recipients of different Streptococcus species. Transductants were obtained from recipients of Streptococcus agalactiae, Streptococcus gordonii, and Streptococcus suis. Retransfer was always achieved, and from S. suis to S. pyogenes occurred at a much greater frequency than in the opposite direction. In transductants Φm46.1 retained its functional properties, such as inducibility with mitomycin C, presence both as a prophage and as a free circular form, and transferability. The transductants shared the same Φm46.1 chromosomal integration site as the donor, at the 3' end of a conserved RNA uracil methyltransferase (rum) gene, which is an integration hotspot for a variety of genetic elements. No transfer occurred to recipients of Streptococcus pneumoniae, Streptococcus oralis, and Streptococcus salivarius, even though rum-like genes were also detected in the sequenced genomes of these species. A largely overlapping 18-bp critical sequence, where the site-specific recombination process presumably takes place, was identified in the rum genes of all recipients, including those of the species yielding no transductants. Growth assays to evaluate the fitness cost of Φm46.1 acquisition disclosed a negligible impact on S. pyogenes, S. agalactiae, and S. gordonii transductants and a noticeable fitness advantage in S. suis. The S. suis transductant also displayed marked overexpression of the autolysin-encoding gene atl.

  2. Lysine-Tryptophan-Crosslinked Peptides Produced by Radical SAM Enzymes in Pathogenic Streptococci.

    PubMed

    Schramma, Kelsey R; Seyedsayamdost, Mohammad R

    2017-04-21

    Macrocycles represent a common structural framework in many naturally occurring peptides. Several strategies exist for macrocyclization, and the enzymes that incorporate them are of great interest, as they enhance our repertoire for creating complex molecules. We recently discovered a new peptide cyclization reaction involving a crosslink between the side chains of lysine and tryptophan that is installed by a radical SAM enzyme. Herein, we characterize relatives of this metalloenzyme from the pathogens Streptococcus agalactiae and Streptococcus suis. Our results show that the corresponding enzymes, which we call AgaB and SuiB, contain multiple [4Fe-4S] clusters and catalyze Lys-Trp crosslink formation in their respective substrates. Subsequent high-resolution-MS and 2D-NMR analyses located the site of macrocyclization. Moreover, we report that AgaB can accept modified substrates containing natural or unnatural amino acids. Aside from providing insights into the mechanism of this unusual modification, the substrate promiscuity of AgaB may be exploited to create diverse macrocyclic peptides.

  3. Mortality and Morbidity Avoidance/Reduction of Respiratory Sickness Immediately Following Exposure to Bioweaponized Microbial Pathogens

    DTIC Science & Technology

    2007-11-02

    vegetative cells of Bacillus anthracis, Clostridium spp., fungal lung pathogens in general and cells of Yersinia pestis, Francisella tularensis, Brucella suis, Salmonella typhi and related bacterial species.

  4. Actinobaculum suis Detection Using Polymerase Chain Reaction

    PubMed Central

    Amigo, Cristina Román; de Gobbi, Debora Dirani Sena; Gomes, Vasco Túlio de Moura; Perina, Danilo do Prado; Nogueira de Lima Filsner, Pedro Henrique; Costa, Barbara Letícia Pereira; Spindola, Maria Garcia; Ferreira, Thais Sebastiana Porfida; Brandão, Paulo Eduardo; Moreno, Andrea Micke

    2012-01-01

    Actinobaculum suis is an important agent related to urinary infection in swine females. Due to its fastidious growth characteristics, the isolation of this anaerobic bacterium is difficult, thus impairing the estimation of its prevalence. The purpose of this study was to develop and test a polymerase chain reaction (PCR) for the detection and identification of A. suis and then compare these results with traditional isolation methods. Bacterial isolation and PCR were performed on one hundred and ninety-two urine samples from sows and forty-five preputial swabs from boars. The results indicate that this PCR was specific for A. suis, presenting a detection limit between 1.0 × 101 CFU/mL and 1.0 × 102 CFU/mL. A. suis frequencies, as measured by PCR, were 8.9% (17/192) in sow urine samples and 82.2% (37/45) in preputial swabs. Assessed using conventional culturing techniques, none of the urine samples were positive for A. suis; however, A. suis was detected in 31.1% (14/45) of the swabs. This PCR technique was shown to be an efficient method for the detection of A. suis in urine and preputial swabs. PMID:23346017

  5. Minimum core genome sequence typing of bacterial pathogens: a unified approach for clinical and public health microbiology.

    PubMed

    Chen, Chen; Zhang, Wen; Zheng, Han; Lan, Ruiting; Wang, Haiyin; Du, Pengcheng; Bai, Xuemei; Ji, Shaobo; Meng, Qiong; Jin, Dong; Liu, Kai; Jing, Huaiqi; Ye, Changyun; Gao, George F; Wang, Lei; Gottschalk, Marcelo; Xu, Jianguo

    2013-08-01

    Bacterial pathogens impose a heavy health burden worldwide. In the new era of high-throughput sequencing and online bioinformatics, real-time genome typing of infecting agents, and in particular those with potential severe clinical outcomes, holds promise for guiding clinical care to limit the detrimental effects of infections and to prevent potential local or global outbreaks. Here, we sequenced and compared 85 isolates of Streptococcus suis, a zoonotic human and swine pathogen, wherein we analyzed 32 recognized serotypes and 75 sequence types representing the diversity of the species and the human clinical isolates with high public health significance. We found that 1,077 of the 2,469 genes are shared by all isolates. Excluding 201 common but mobile genes, 876 genes were defined as the minimum core genome (MCG) of the species. Of 190,894 single-nucleotide polymorphisms (SNPs) identified, 58,501 were located in the MCG genes and were referred to as MCG SNPs. A population structure analysis of these MCG SNPs classified the 85 isolates into seven MCG groups, of which MCG group 1 includes all isolates from human infections and outbreaks. Our MCG typing system for S. suis provided a clear separation of groups containing human-associated isolates from those containing animal-associated isolates. It also separated the group containing outbreak isolates, including those causing life-threatening streptococcal toxic shock-like syndrome, from sporadic or less severe meningitis or bacteremia-only isolates. The typing system facilitates the application of genome data to the fields of clinical medicine and epidemiology and to the surveillance of S. suis. The MCG groups may also be used as the taxonomical units of S. suis to define bacterial subpopulations with the potential to cause severe clinical infections and large-scale outbreaks.

  6. Antimicrobial susceptibility monitoring of respiratory tract pathogens isolated from diseased cattle and pigs across Europe: the VetPath study.

    PubMed

    de Jong, Anno; Thomas, Valérie; Simjee, Shabbir; Moyaert, Hilde; El Garch, Farid; Maher, Kirsty; Morrissey, Ian; Butty, Pascal; Klein, Ulrich; Marion, Hervé; Rigaut, Delphine; Vallé, Michel

    2014-08-06

    VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme collecting pathogens from diseased antimicrobial non-treated cattle, pigs and poultry. In the current study, 1001 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. Non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 11 countries during 2002-2006. Pasteurella multocida and Mannheimia haemolytica from cattle and P. multocida, Actinobacillus pleuropneumoniae and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MICs of 16 antibiotics were assessed centrally by broth microdilution following CLSI recommendations. Results were interpreted using CLSI breakpoints where available. P. multocida (231) and M. haemolytica (138) isolates were all susceptible to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin and trimethoprim/sulfamethoxazole. Resistance to florfenicol and spectinomycin was 0.4% and 3.5% in P. multocida, respectively, and absent in M. haemolytica isolates. Tetracycline resistance was 5.7% and 14.6% for P. multocida and M. haemolytica. In pigs, 230 P. multocida, 220 A. pleuropneumoniae and 182 S. suis isolates were recovered. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tiamulin and tilmicosin was absent or <1%. Trimethoprim/sulfamethoxazole resistance was 3-6% and tetracycline resistance varied from 14.7% in A. pleuropneumoniae to 81.8% in S. suis. In conclusion, low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from cattle and pigs. Since for approximately half of the antibiotics in this panel no CLSI-defined breakpoints were available, setting of the missing veterinary breakpoints is important.

  7. Minimum Core Genome Sequence Typing of Bacterial Pathogens: a Unified Approach for Clinical and Public Health Microbiology

    PubMed Central

    Chen, Chen; Zhang, Wen; Zheng, Han; Lan, Ruiting; Wang, Haiyin; Du, Pengcheng; Bai, Xuemei; Ji, Shaobo; Meng, Qiong; Jin, Dong; Liu, Kai; Jing, Huaiqi; Ye, Changyun; Gao, George F.; Wang, Lei; Gottschalk, Marcelo

    2013-01-01

    Bacterial pathogens impose a heavy health burden worldwide. In the new era of high-throughput sequencing and online bioinformatics, real-time genome typing of infecting agents, and in particular those with potential severe clinical outcomes, holds promise for guiding clinical care to limit the detrimental effects of infections and to prevent potential local or global outbreaks. Here, we sequenced and compared 85 isolates of Streptococcus suis, a zoonotic human and swine pathogen, wherein we analyzed 32 recognized serotypes and 75 sequence types representing the diversity of the species and the human clinical isolates with high public health significance. We found that 1,077 of the 2,469 genes are shared by all isolates. Excluding 201 common but mobile genes, 876 genes were defined as the minimum core genome (MCG) of the species. Of 190,894 single-nucleotide polymorphisms (SNPs) identified, 58,501 were located in the MCG genes and were referred to as MCG SNPs. A population structure analysis of these MCG SNPs classified the 85 isolates into seven MCG groups, of which MCG group 1 includes all isolates from human infections and outbreaks. Our MCG typing system for S. suis provided a clear separation of groups containing human-associated isolates from those containing animal-associated isolates. It also separated the group containing outbreak isolates, including those causing life-threatening streptococcal toxic shock-like syndrome, from sporadic or less severe meningitis or bacteremia-only isolates. The typing system facilitates the application of genome data to the fields of clinical medicine and epidemiology and to the surveillance of S. suis. The MCG groups may also be used as the taxonomical units of S. suis to define bacterial subpopulations with the potential to cause severe clinical infections and large-scale outbreaks. PMID:23720795

  8. Streptococcus pneumoniae, le transformiste.

    PubMed

    Johnston, Calum; Campo, Nathalie; Bergé, Matthieu J; Polard, Patrice; Claverys, Jean-Pierre

    2014-03-01

    Streptococcus pneumoniae (the pneumococcus) is an important human pathogen. Natural genetic transformation, which was discovered in this species, involves internalization of exogenous single-stranded DNA and its incorporation into the chromosome. It allows acquisition of pathogenicity islands and antibiotic resistance and promotes vaccine escape via capsule switching. This opinion article discusses how recent advances regarding several facets of pneumococcal transformation support the view that the process has evolved to maximize plasticity potential in this species, making the pneumococcus le transformiste of the bacterial kingdom and providing an advantage in the constant struggle between this pathogen and its host.

  9. Evidence for a primate origin of zoonotic Helicobacter suis colonizing domesticated pigs.

    PubMed

    Flahou, Bram; Rossi, Mirko; Bakker, Jaco; Langermans, Jan Am; Heuvelman, Edwin; Solnick, Jay V; Martin, Miriam E; O'Rourke, Jani; Ngoan, Le Duc; Hoa, Nguyen Xuan; Nakamura, Masahiko; Øverby, Anders; Matsui, Hidenori; Ota, Hiroyoshi; Matsumoto, Takehisa; Foss, Dennis L; Kopta, Laurice A; Omotosho, Oladipo; Franciosini, Maria Pia; Casagrande Proietti, Patrizia; Guo, Aizhen; Liu, Han; Borilova, Gabriela; Bracarense, Ana Paula; Lindén, Sara K; De Bruyckere, Sofie; Zhang, Guangzhi; De Witte, Chloë; Smet, Annemieke; Pasmans, Frank; Ducatelle, Richard; Corander, Jukka; Haesebrouck, Freddy

    2017-09-08

    Helicobacter suis is the second most prevalent Helicobacter species in the stomach of humans suffering from gastric disease. This bacterium mainly inhabits the stomach of domesticated pigs, in which it causes gastric disease, but it appears to be absent in wild boars. Interestingly, it also colonizes the stomach of asymptomatic rhesus and cynomolgus monkeys. The origin of modern human-, pig- or non-human primate-associated H. suis strains in these respective host populations was hitherto unknown. Here we show that H. suis in pigs possibly originates from non-human primates. Our data suggest that a host jump from macaques to pigs happened between 100 000 and 15 000 years ago and that pig domestication has had a significant impact on the spread of H. suis in the pig population, from where this pathogen occasionally infects humans. Thus, in contrast to our expectations, H. suis appears to have evolved in its main host in a completely different way than its close relative Helicobacter pylori in humans.The ISME Journal advance online publication, 8 September 2017; doi:10.1038/ismej.2017.145.

  10. Immune responses and protection induced by Brucella suis S2 bacterial ghosts in mice.

    PubMed

    Liu, Jun; Li, Yi; Sun, Yang; Ji, Xue; Zhu, Lingwei; Guo, Xuejun; Zhou, Wei; Zhou, Bo; Liu, Shuang; Zhang, Ruian; Feng, Shuzhang

    2015-08-15

    With the purpose of generating Brucella suis bacterial ghosts and investigating the immunogenicity of bacterial ghosts as a vaccine candidate, the lysis gene E and temperature-sensitive regulator cassette were cloned into a shuttle plasmid, pBBR1MCS-2, for construction of a recombinant temperature-sensitive shuttle lysis plasmid, pBBR1MCS-E. pBBR1MCS-E was then introduced into attenuated B. suis live vaccine S2 bacteria, and the resultant transformants were used for production of B. suis ghosts (BSGs) by inducing lysis gene E expression. The BSGs were characterized by observing their morphology by transmission electron microscopy. The safety and immunogenicity of BSGs were further evaluated using a murine model, the result suggested that BSG was as safe as formalin-killed B. suis. In mice, BSG demonstrated a similar capacity of inducing pathogen-specific serum IgG antibody response, spleen CD3(+) and CD4(+) T cell responses, induce secretion of gamma interferon and interleukin-4, and protection levels against Brucella melitensis 16M challenge, as the attenuated B. suis live vaccine. These data suggesting that BSG could confer protection against Brucella infection in a mouse model of disease and may be developed as a new vaccine candidate against Brucella infection.

  11. Nationwide survey of the development of drug-resistant pathogens in the pediatric field in 2007 and 2010: drug sensitivity of Streptococcus pneumoniae in Japan (second report).

    PubMed

    Tajima, Takeshi; Sato, Yoshitake; Toyonaga, Yoshikiyo; Hanaki, Hideaki; Sunakawa, Keisuke

    2013-06-01

    We previously conducted nationwide surveillance of Streptococcus pneumoniae in 2000-2001 (period 1) and 2004 (period 2) and reported the findings. Subsequent surveillance surveys conducted in 2007 (period 3) and 2010 (period 4) are now reported. Bacterial strains were clinically isolated from children with meningitis, sepsis, and respiratory tract infections at 27 hospitals participating in the Drug-Resistant Pathogen Surveillance Group in Pediatric Infectious Disease. Twenty-one drugs were investigated for 283 isolated strains in period 3, and 24 drugs were investigated for 459 strains in period 4. In period 3, 43.8 % of strains were penicillin-susceptible S. pneumoniae (PSSP), 52.3 % were penicillin-intermediate S. pneumoniae (PISP), and 3.9 % were penicillin-resistant S. pneumoniae (PRSP). In period 4, the percentages were PSSP 23.1 %, PISP 49.9 %, and PRSP 27.0 %. The resistance rates were 56.2 % and 76.9 %, respectively. Drug sensitivity was best with panipenem, at a minimum inhibitory concentration (MIC)90 ≤0.063 μg/ml in period 3, and with tebipenem (MIC90 ≤ 0.063 μg/ml) in period 4. Patients' background factors related to increased bacterial resistance were investigated, and significant differences were found depending on whether a child had siblings (P = 0.0056) or was a daycare center attendee (P = 0.0195) in period 3, and age category (P = 0.0256) in period 4. No factors were common to both periods 3 and 4. Pneumococcus is a major causative organism of pediatric infectious disease, and we plan to continue conducting surveillance and providing information in the future.

  12. Autoinducer-2 of Streptococcus mitis as a Target Molecule to Inhibit Pathogenic Multi-Species Biofilm Formation In Vitro and in an Endotracheal Intubation Rat Model

    PubMed Central

    Wang, Zhengli; Xiang, Qingqing; Yang, Ting; Li, Luquan; Yang, Jingli; Li, Hongong; He, Yu; Zhang, Yunhui; Lu, Qi; Yu, Jialin

    2016-01-01

    Streptococcus mitis (S. mitis) and Pseudomonas aeruginosa (P. aeruginosa) are typically found in the upper respiratory tract of infants. We previously found that P. aeruginosa and S. mitis were two of the most common bacteria in biofilms on newborns’ endotracheal tubes (ETTs) and in their sputa and that S. mitis was able to produce autoinducer-2 (AI-2), whereas P. aeruginosa was not. Recently, we also found that exogenous AI-2 and S. mitis could influence the behaviors of P. aeruginosa. We hypothesized that S. mitis contributes to this interspecies interaction and that inhibition of AI-2 could result in inhibition of these effects. To test this hypothesis, we selected PAO1 as a representative model strain of P. aeruginosa and evaluated the effect of S. mitis as well as an AI-2 analog (D-ribose) on mono- and co-culture biofilms in both in vitro and in vivo models. In this context, S. mitis promoted PAO1 biofilm formation and pathogenicity. Dual-species (PAO1 and S. mitis) biofilms exhibited higher expression of quorum sensing genes than single-species (PAO1) biofilms did. Additionally, ETTs covered in dual-species biofilms increased the mortality rate and aggravated lung infection compared with ETTs covered in mono-species biofilms in an endotracheal intubation rat model, all of which was inhibited by D-ribose. Our results demonstrated that S. mitis AI-2 plays an important role in interspecies interactions with PAO1 and may be a target for inhibition of biofilm formation and infection in ventilator-associated pneumonia. PMID:26903968

  13. Changing Trends in Antimicrobial Resistance and Serotypes of Streptococcus pneumoniae Isolates in Asian Countries: an Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study

    PubMed Central

    Kim, So Hyun; Chung, Doo Ryeon; Thamlikitkul, Visanu; Yang, Yonghong; Wang, Hui; Lu, Min; So, Thomas Man-kit; Hsueh, Po-Ren; Yasin, Rohani M.; Carlos, Celia C.; Pham, Hung Van; Lalitha, M. K.; Shimono, Nobuyuki; Perera, Jennifer; Shibl, Atef M.; Baek, Jin Yang; Kang, Cheol-In; Ko, Kwan Soo; Peck, Kyong Ran

    2012-01-01

    Antimicrobial resistance in Streptococcus pneumoniae remains a serious concern worldwide, particularly in Asian countries, despite the introduction of heptavalent pneumococcal conjugate vaccine (PCV7). The Asian Network for Surveillance of Resistant Pathogens (ANSORP) performed a prospective surveillance study of 2,184 S. pneumoniae isolates collected from patients with pneumococcal infections from 60 hospitals in 11 Asian countries from 2008 to 2009. Among nonmeningeal isolates, the prevalence rate of penicillin-nonsusceptible pneumococci (MIC, ≥4 μg/ml) was 4.6% and penicillin resistance (MIC, ≥8 μg/ml) was extremely rare (0.7%). Resistance to erythromycin was very prevalent in the region (72.7%); the highest rates were in China (96.4%), Taiwan (84.9%), and Vietnam (80.7%). Multidrug resistance (MDR) was observed in 59.3% of isolates from Asian countries. Major serotypes were 19F (23.5%), 23F (10.0%), 19A (8.2%), 14 (7.3%), and 6B (7.3%). Overall, 52.5% of isolates showed PCV7 serotypes, ranging from 16.1% in Philippines to 75.1% in Vietnam. Serotypes 19A (8.2%), 3 (6.2%), and 6A (4.2%) were the most prominent non-PCV7 serotypes in the Asian region. Among isolates with serotype 19A, 86.0% and 79.8% showed erythromycin resistance and MDR, respectively. The most remarkable findings about the epidemiology of S. pneumoniae in Asian countries after the introduction of PCV7 were the high prevalence of macrolide resistance and MDR and distinctive increases in serotype 19A. PMID:22232285

  14. Tetracycline Susceptibility in Chlamydia suis Pig Isolates.

    PubMed

    Donati, Manuela; Balboni, Andrea; Laroucau, Karine; Aaziz, Rachid; Vorimore, Fabien; Borel, Nicole; Morandi, Federico; Vecchio Nepita, Edoardo; Di Francesco, Antonietta

    2016-01-01

    The aims of the present study were to assess the prevalence of Chlamydia suis in an Italian pig herd, determine the tetracycline susceptibility of C. suis isolates, and evaluate tet(C) and tetR(C) gene expression. Conjunctival swabs from 20 pigs were tested for C. suis by real-time polymerase chain reaction, and 55% (11) were positive. C. suis was then isolated from 11 conjunctival swabs resampled from the same herd. All positive samples and isolates were positive for the tet(C) resistance gene. The in vitro susceptibility to tetracycline of the C. suis isolates showed MIC values ranging from 0.5 to 4 μg/mL. Tet(C) and tetR(C) transcripts were found in all the isolates, cultured both in the absence and presence of tetracycline. This contrasts with other Gram-negative bacteria in which both genes are repressed in the absence of the drug. Further investigation into tet gene regulation in C. suis is needed.

  15. Tetracycline Susceptibility in Chlamydia suis Pig Isolates

    PubMed Central

    Donati, Manuela; Balboni, Andrea; Laroucau, Karine; Aaziz, Rachid; Vorimore, Fabien; Borel, Nicole; Morandi, Federico; Vecchio Nepita, Edoardo; Di Francesco, Antonietta

    2016-01-01

    The aims of the present study were to assess the prevalence of Chlamydia suis in an Italian pig herd, determine the tetracycline susceptibility of C. suis isolates, and evaluate tet(C) and tetR(C) gene expression. Conjunctival swabs from 20 pigs were tested for C. suis by real-time polymerase chain reaction, and 55% (11) were positive. C. suis was then isolated from 11 conjunctival swabs resampled from the same herd. All positive samples and isolates were positive for the tet(C) resistance gene. The in vitro susceptibility to tetracycline of the C. suis isolates showed MIC values ranging from 0.5 to 4 μg/mL. Tet(C) and tetR(C) transcripts were found in all the isolates, cultured both in the absence and presence of tetracycline. This contrasts with other Gram-negative bacteria in which both genes are repressed in the absence of the drug. Further investigation into tet gene regulation in C. suis is needed. PMID:26913523

  16. Streptococcus zooepidemicus and Streptococcus equi evolution: the role of CRISPRs.

    PubMed

    Waller, Andrew S; Robinson, Carl

    2013-12-01

    The host-restricted bacterium Streptococcus equi is the causative agent of equine strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation of the lymph nodes of the head and neck, leading to significant welfare and economic cost. S. equi is believed to have evolved from an ancestral strain of Streptococcus zooepidemicus, an opportunistic pathogen of horses and other animals. Comparison of the genome of S. equi strain 4047 with those of S. zooepidemicus identified examples of gene loss due to mutation and deletion, and gene gain through the acquisition of mobile genetic elements that have probably shaped the pathogenic specialization of S. equi. In particular, deletion of the CRISPR (clustered regularly interspaced short palindromic repeats) locus in the ancestor of S. equi may have predisposed the bacterium to acquire and incorporate new genetic material into its genome. These include four prophages and a novel integrative conjugative element. The virulence cargo carried by these mobile genetic elements is believed to have shaped the ability of S. equi to cause strangles. Further sequencing of S. zooepidemicus has highlighted the diversity of this opportunistic pathogen. Again, CRISPRs are postulated to influence evolution, balancing the need for gene gain over genome stability. Analysis of spacer sequences suggest that these pathogens may be susceptible to a limited range of phages and provide further evidence of cross-species exchange of genetic material among Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus dysgalactiae.

  17. Synergism between Trichuris suis and the microbial flora of the large intestine causing dysentery in pigs.

    PubMed Central

    Rutter, J M; Beer, R J

    1975-01-01

    The role of the microbial flora of the large intestine in experimental Trichuris suis infection was studied by comparing the clinical syndrome in conventionally reared (CR) pigs, specific pathogen-free pigs, and gnotobiotic pigs. Thedisease in CR pigs was characterized by a severe mucohemorrhagic enteritis; in contrast, a mild catarrhal enteritis was observed in specific pathogen-free and gnotobiotic pigs.Spirochaetes and vibrio-like organisms were observed only in CR pigs and increased during the clinical phase of the disease. The clinical syndrome was not transmitted by oral administration of intestinal or fecal material from infected CR pigs to CR pigs free of T. suis. Smaller numbers of T. suis produced diarrhea in CR pigs and significantly reduced the growth rates of infected animals; clinical signs and the reduction in growth rate was prevented by incorporating an antibacterial substance (dimetridazole) in the food. Although clinical trichuriasis closely resembles swin dysentery, the two syndromes seem to be distinct. The present results suggest that a microbial component acts synergistically with T. suis to produce the severe clinical syndrome in CR pigs, but identification of the microbial component and the mechanism by which clinical signs are produced await further studies of the bacterial flora of the large intestine of pigs. Images PMID:1167536

  18. Brucella suis Vaccine Strain 2 Induces Endoplasmic Reticulum Stress that Affects Intracellular Replication in Goat Trophoblast Cells In vitro

    PubMed Central

    Wang, Xiangguo; Lin, Pengfei; Li, Yang; Xiang, Caixia; Yin, Yanlong; Chen, Zhi; Du, Yue; Zhou, Dong; Jin, Yaping; Wang, Aihua

    2016-01-01

    Brucella has been reported to impair placental trophoblasts, a cellular target where Brucella efficiently replicates in association with the endoplasmic reticulum (ER), and ultimately trigger abortion in pregnant animals. However, the precise effects of Brucella on trophoblast cells remain unclear. Here, we describe the infection and replication of Brucella suis vaccine strain 2 (B.suis.S2) in goat trophoblast cells (GTCs) and the cellular and molecular responses induced in vitro. Our studies demonstrated that B.suis.S2 was able to infect and proliferate to high titers, hamper the proliferation of GTCs and induce apoptosis due to ER stress. Tunicamycin (Tm), a pharmacological chaperone that strongly mounts ER stress-induced apoptosis, inhibited B.suis.S2 replication in GTCs. In addition, 4 phenyl butyric acid (4-PBA), a pharmacological chaperone that alleviates ER stress-induced apoptosis, significantly enhanced B.suis.S2 replication in GTCs. The Unfolded Protein Response (UPR) chaperone molecule GRP78 also promoted B.suis.S2 proliferation in GTCs by inhibiting ER stress-induced apoptosis. We also discovered that the IRE1 pathway, but not the PERK or ATF6 pathway, was activated in the process. However, decreasing the expression of phosphoIRE1α and IRE1α proteins with Irestatin 9389 (IRE1 antagonist) in GTCs did not affect the proliferation of B.suis.S2. Although GTC implantation was not affected upon B.suis.S2 infection, progesterone secretion was suppressed, and prolactin and estrogen secretion increased; these effects were accompanied by changes in the expression of genes encoding key steroidogenic enzymes. This study systematically explored the mechanisms of abortion in Brucella infection from the viewpoint of pathogen invasion, ER stress and reproductive endocrinology. Our findings may provide new insight for understanding the mechanisms involved in goat abortions caused by Brucella infection. PMID:26904517

  19. Brucella suis Vaccine Strain 2 Induces Endoplasmic Reticulum Stress that Affects Intracellular Replication in Goat Trophoblast Cells In vitro.

    PubMed

    Wang, Xiangguo; Lin, Pengfei; Li, Yang; Xiang, Caixia; Yin, Yanlong; Chen, Zhi; Du, Yue; Zhou, Dong; Jin, Yaping; Wang, Aihua

    2016-01-01

    Brucella has been reported to impair placental trophoblasts, a cellular target where Brucella efficiently replicates in association with the endoplasmic reticulum (ER), and ultimately trigger abortion in pregnant animals. However, the precise effects of Brucella on trophoblast cells remain unclear. Here, we describe the infection and replication of Brucella suis vaccine strain 2 (B.suis.S2) in goat trophoblast cells (GTCs) and the cellular and molecular responses induced in vitro. Our studies demonstrated that B.suis.S2 was able to infect and proliferate to high titers, hamper the proliferation of GTCs and induce apoptosis due to ER stress. Tunicamycin (Tm), a pharmacological chaperone that strongly mounts ER stress-induced apoptosis, inhibited B.suis.S2 replication in GTCs. In addition, 4 phenyl butyric acid (4-PBA), a pharmacological chaperone that alleviates ER stress-induced apoptosis, significantly enhanced B.suis.S2 replication in GTCs. The Unfolded Protein Response (UPR) chaperone molecule GRP78 also promoted B.suis.S2 proliferation in GTCs by inhibiting ER stress-induced apoptosis. We also discovered that the IRE1 pathway, but not the PERK or ATF6 pathway, was activated in the process. However, decreasing the expression of phosphoIRE1α and IRE1α proteins with Irestatin 9389 (IRE1 antagonist) in GTCs did not affect the proliferation of B.suis.S2. Although GTC implantation was not affected upon B.suis.S2 infection, progesterone secretion was suppressed, and prolactin and estrogen secretion increased; these effects were accompanied by changes in the expression of genes encoding key steroidogenic enzymes. This study systematically explored the mechanisms of abortion in Brucella infection from the viewpoint of pathogen invasion, ER stress and reproductive endocrinology. Our findings may provide new insight for understanding the mechanisms involved in goat abortions caused by Brucella infection.

  20. Functional validation of putative toxin-antitoxin genes from the Gram-positive pathogen Streptococcus pneumoniae: phd-doc is the fourth bona-fide operon.

    PubMed

    Chan, Wai Ting; Yeo, Chew Chieng; Sadowy, Ewa; Espinosa, Manuel

    2014-01-01

    Bacterial toxin-antitoxin (TAs) loci usually consist of two genes organized as an operon, where their products are bound together and inert under normal conditions. However, under stressful circumstances the antitoxin, which is more labile, will be degraded more rapidly, thereby unleashing its cognate toxin to act on the cell. This, in turn, causes cell stasis or cell death, depending on the type of TAs and/or time of toxin exposure. Previously based on in silico analyses, we proposed that Streptococcus pneumoniae, a pathogenic Gram-positive bacterium, may harbor between 4 and 10 putative TA loci depending on the strains. Here we have chosen the pneumococcal strain Hungary(19A)-6 which contains all possible 10 TA loci. In addition to the three well-characterized operons, namely relBE2, yefM-yoeB, and pezAT, we show here the functionality of a fourth operon that encodes the pneumococcal equivalent of the phd-doc TA. Transcriptional fusions with gene encoding Green Fluorescent Protein showed that the promoter was slightly repressed by the Phd antitoxin, and exhibited almost background values when both Phd-Doc were expressed together. These findings demonstrate that phd-doc shows the negative self-regulatory features typical for an authentic TA. Further, we also show that the previously proposed TAs XreA-Ant and Bro-XreB, although they exhibit a genetic organization resembling those of typical TAs, did not appear to confer a functional behavior corresponding to bona fide TAs. In addition, we have also discovered new interesting bioinformatics results for the known pneumococcal TAs RelBE2 and PezAT. A global analysis of the four identified toxins-antitoxins in the pneumococcal genomes (PezAT, RelBE2, YefM-YoeB, and Phd-Doc) showed that RelBE2 and Phd-Doc are the most conserved ones. Further, there was good correlation among TA types, clonal complexes and sequence types in the 48 pneumococcal strains analyzed.

  1. First Characterization of Fluoroquinolone Resistance in Streptococcus suis▿

    PubMed Central

    Escudero, Jose Antonio; San Millan, Alvaro; Catalan, Ana; de la Campa, Adela G.; Rivero, Estefania; Lopez, Gema; Dominguez, Lucas; Moreno, Miguel Angel; Gonzalez-Zorn, Bruno

    2007-01-01

    We have identified and sequenced the genes encoding the quinolone-resistance determining region (QRDR) of ParC and GyrA in fluoroquinolone-susceptible and -resistant Streptococcus suis clinical isolates. Resistance is the consequence of single point mutations in the QRDRs of ParC and GyrA and is not due to clonal spread of resistant strains or horizontal gene transfer with other bacteria. PMID:17116660

  2. Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus ("Streptococcus milleri group") are of different clinical importance and are not equally associated with abscess.

    PubMed

    Claridge, J E; Attorri, S; Musher, D M; Hebert, J; Dunbar, S

    2001-05-15

    Difficulties in distinguishing organisms of the "Streptococcus milleri group" (SMG; Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus), have caused ambiguity in determining their pathogenic potential. We reviewed 118 cases in which SMG isolates had been identified using 16S rDNA sequence. S. constellatus and S. anginosus were isolated far more frequently than was S. intermedius. Nearly all isolates of S. intermedius and most isolates of S. constellatus, but only 19% of those of S. anginosus, were associated with abscess. Our findings suggest that speciation of the SMG may guide diagnostic evaluation, give insight into the possible role of coinfecting organisms, and help assess the need to search for occult abscess.

  3. Draft Genome Sequence of Streptococcus pyogenes Strain 06BA18369, a Human Pathogen Associated with Skin and Soft Tissue Infections in Northern Canada.

    PubMed

    McDonald, Ryan R; Golding, George R; Irvine, James; Graham, Morag R; Tyler, Shaun; Mulvey, Michael R; Levett, Paul N

    2013-06-27

    We report the draft sequence of Streptococcus pyogenes 06BA18369 (emm type 41.2, sequence type 579 [ST579]), isolated from a skin and soft tissue infection (SSTI) mixed with Staphylococcus aureus. This genome provides insight into the genetic composition of S. pyogenes strains associated with mixed SSTIs.

  4. Trichuris suis ova in inflammatory bowel disease.

    PubMed

    Schölmerich, Jürgen

    2013-01-01

    Some but not all epidemiological studies suggest that helminth infection in childhood protects against development of inflammatory bowel disease (IBD) in later years. In animal models of IBD, helminths have shown protective effects and changed bacterial flora in the gut. Based on these concepts, small trials and series have been published showing some positive effects of Trichuris suis ova in ulcerative colitis and Crohn's disease. Currently, large randomized placebo-controlled trials are under way. Results remain to be awaited in order to clarify a possible role of T. suis ova in the treatment of IBD.

  5. Human Streptococcus agalactiae isolate in Nile tilapia (Oreochromis niloticus)

    USDA-ARS?s Scientific Manuscript database

    Streptococcus agalactiae, the Lancefield group B Streptococcus (GBS), long recognized as a mammalian pathogen, is an emerging pathogen to fish. We show that a GBS serotype Ia, multilocus sequence type ST-7 isolate from a human neonatal meningitis clinical case causes disease signs and mortality in N...

  6. Effect of Different Adjuvants on Protection and Side-Effects Induced by Helicobacter suis Whole-Cell Lysate Vaccination.

    PubMed

    Bosschem, Iris; Bayry, Jagadeesh; De Bruyne, Ellen; Van Deun, Kim; Smet, Annemieke; Vercauteren, Griet; Ducatelle, Richard; Haesebrouck, Freddy; Flahou, Bram

    2015-01-01

    Helicobacter suis (H. suis) is a widespread porcine gastric pathogen, which is also of zoonotic importance. The first goal of this study was to investigate the efficacy of several vaccine adjuvants (CpG-DNA, Curdlan, Freund's Complete and Incomplete, Cholera toxin), administered either subcutaneously or intranasally along with H. suis whole-cell lysate, to protect against subsequent H. suis challenge in a BALB/c infection model. Subcutaneous immunization with Freund's complete (FC)/lysate and intranasal immunization with Cholera toxin (CT)/lysate were shown to be the best options for vaccination against H. suis, as determined by the amount of colonizing H. suis bacteria in the stomach, although adverse effects such as post-immunization gastritis/pseudo-pyloric metaplasia and increased mortality were observed, respectively. Therefore, we decided to test alternative strategies, including sublingual vaccine administration, to reduce the unwanted side-effects. A CCR4 antagonist that transiently inhibits the migration of regulatory T cells was also included as a new adjuvant in this second study. Results confirmed that immunization with CT (intranasally or sublingually) is among the most effective vaccination protocols, but increased mortality was still observed. In the groups immunized subcutaneously with FC/lysate and CCR4 antagonist/lysate, a significant protection was observed. Compared to the FC/lysate immunized group, gastric pseudo-pyloric metaplasia was less severe or even absent in the CCR4 antagonist/lysate immunized group. In general, an inverse correlation was observed between IFN-γ, IL-4, IL-17, KC, MIP-2 and LIX mRNA expression and H. suis colonization density, whereas lower IL-10 expression levels were observed in partially protected animals.

  7. Development of colloidal gold-based immunochromatographic assay for rapid detection of Mycoplasma suis in porcine plasma.

    PubMed

    Meng, Kai; Sun, Wenjing; Zhao, Peng; Zhang, Limei; Cai, Dongjie; Cheng, Ziqiang; Guo, Huijun; Liu, Jianzhu; Yang, Dubao; Wang, Shujing; Chai, Tongjie

    2014-05-15

    A one-step immunochromatographic assay using gold nanoparticles coated with polyclonal antibody (pAb) against Mycoplasma suis (M. suis) was developed in this study for the detection of M. suis in porcine plasma. The colloidal gold was prepared by the reduction of gold salt with sodium citrate coupled with pAb against M. suis. The pAb was produced by immunizing the BALB/c mice with recombinant MSG1 (rMSG1) protein from M. suis expressed in Escherichia coli. The optimal concentrations of the capture antibody and the coating antibody were 12 μg/ml and 1.5 mg/ml, respectively, and that of the blocking buffer was 1% bovine serum albumin. The lower detection limit of the immunochromatographic assay test was 100 ng/ml with visual detection under optimal conditions of analysis. Classical swine fever virus, porcine reproductive and respiratory syndrome virus, swine pneumonia mycoplasma, swine toxoplasma, and porcine parvovirus were used to evaluate the specificity of the immunochromatographic strips. No cross-reaction of the antibodies with other related swine pathogens was observed. This qualitative test based on the visual evaluation of the results did not require any equipment. The assay time for M. suis detection was less than 10 min, suitable for rapid detection at the grassroots level. The one-step colloidal gold immunochromatographic strips that we developed had high specificity and sensitivity. Therefore, this method would be feasible, convenient, rapid, and effective for detecting M. suis in porcine plasma. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. The Chlamydia suis Genome Exhibits High Levels of Diversity, Plasticity, and Mobile Antibiotic Resistance: Comparative Genomics of a Recent Livestock Cohort Shows Influence of Treatment Regimes

    PubMed Central

    Wanninger, Sabrina; Bachmann, Nathan; Marti, Hanna; Qi, Weihong; Donati, Manuela; di Francesco, Antonietta; Polkinghorne, Adam; Borel, Nicole

    2017-01-01

    Chlamydia suis is an endemic pig pathogen, belonging to a fascinating genus of obligate intracellular pathogens. Of particular interest, this is the only chlamydial species to have naturally acquired genes encoding for tetracycline resistance. To date, the distribution and mobility of the Tet-island are not well understood. Our study focused on whole genome sequencing of 29 C. suis isolates from a recent porcine cohort within Switzerland, combined with data from USA tetracycline-resistant isolates. Our findings show that the genome of C. suis is very plastic, with unprecedented diversity, highly affected by recombination and plasmid exchange. A large diversity of isolates circulates within Europe, even within individual Swiss farms, suggesting that C. suis originated around Europe. New World isolates have more restricted diversity and appear to derive from European isolates, indicating that historical strain transfers to the United States have occurred. The architecture of the Tet-island is variable, but the tetA(C) gene is always intact, and recombination has been a major factor in its transmission within C. suis. Selective pressure from tetracycline use within pigs leads to a higher number of Tet-island carrying isolates, which appear to be lost in the absence of such pressure, whereas the loss or gain of the Tet-island from individual strains is not observed. The Tet-island appears to be a recent import into the genome of C. suis, with a possible American origin. PMID:28338777

  9. The Chlamydia suis genome exhibits high levels of diversity, plasticity and mobile antibiotic resistance: comparative genomics of a recent livestock cohort shows influence of treatment regimes.

    PubMed

    Seth-Smith, Helena M B; Wanninger, Sabrina; Bachmann, Nathan; Marti, Hanna; Qi, Weihong; Donati, Manuela; di Francesco, Antonietta; Polkinghorne, Adam; Borel, Nicole

    2017-03-02

    Chlamydia suis is an endemic pig pathogen, belonging to a fascinating genus of obligate intracellular pathogens. Of particular interest, this is the only chlamydial species to have naturally acquired genes encoding for tetracycline resistance. To date, the distribution and mobility of the Tet-island is not well understood. Our study focused on whole genome sequencing of 29 C. suis isolates from a recent porcine cohort within Switzerland, combined with data from USA tetracycline-resistant isolates. Our findings show that the genome of C. suis is very plastic, with unprecedented diversity, highly affected by recombination and plasmid exchange. A large diversity of isolates circulates within Europe, even within individual Swiss farms, suggesting that C. suis originated around Europe. New World isolates have more restricted diversity and appear to derive from European isolates, indicating that historical strain transfers to the USA have occurred. The architecture of the Tet-island is variable, but the tetA(C) gene is always intact, and recombination has been a major factor in its transmission within C. suis. Selective pressure from tetracycline use within pigs leads to a higher number of Tet-island carrying isolates, which appear to be lost in the absence of such pressure, whereas the loss or gain of the Tet-island from individual strains is not observed. The Tet-island appears to be a recent import into the genome of C. suis, with a possible American origin.

  10. Capsular typing of Streptococcus agalactiae (Lancefield group B streptococci) from fish using multiplex PCR and serotyping

    USDA-ARS?s Scientific Manuscript database

    Streptococcus spp. including Streptococcus agalactiae (Lancefield group B streptococci) are considered emerging pathogens responsible for approximately $1 billion USD in annual losses to the global tilapia (Oreochromis sp.) aquaculture industry. This study evaluated a published multiplex PCR capsul...

  11. Characterization of Brucella suis clpB and clpAB Mutants and Participation of the Genes in Stress Responses

    PubMed Central

    Ekaza, Euloge; Teyssier, Jacques; Ouahrani-Bettache, Safia; Liautard, Jean-Pierre; Köhler, Stephan

    2001-01-01

    Pathogens often encounter stressful conditions inside their hosts. In the attempt to characterize the stress response in Brucella suis, a gene highly homologous to Escherichia coli clpB was isolated from Brucella suis, and the deduced amino acid sequence showed features typical of the ClpB ATPase family of stress response proteins. Under high-temperature stress conditions, ClpB of B. suis was induced, and an isogenic B. suis clpB mutant showed increased sensitivity to high temperature, but also to ethanol stress and acid pH. The effects were reversible by complementation. Simultaneous inactivation of clpA and clpB resulted in a mutant that was sensitive to oxidative stress. In B. suis expressing gfp, ClpA but not ClpB participated in degradation of the green fluorescent protein at 42°C. We concluded that ClpB was responsible for tolerance to several stresses and that the lethality caused by harsh environmental conditions may have similar molecular origins. PMID:11274130

  12. Monitoring of antimicrobial susceptibility of respiratory tract pathogens isolated from diseased cattle and pigs across Europe, 2009-2012: VetPath results.

    PubMed

    El Garch, Farid; de Jong, Anno; Simjee, Shabbir; Moyaert, Hilde; Klein, Ulrich; Ludwig, Carolin; Marion, Hervé; Haag-Diergarten, Silke; Richard-Mazet, Alexandra; Thomas, Valérie; Siegwart, Ed

    2016-10-15

    VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme that collects pathogens from diseased cattle, pigs and poultry. In the current study, 996 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. Non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 10 countries during 2009-2012. Pasteurella multocida, Mannheimia haemolytica and Histophilus somni from cattle and P. multocida, Actinobacillus pleuropneumoniae, Haemophilus parasuis, Bordetella bronchiseptica and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MIC values of 16 or 17 antibiotics were assessed centrally by broth microdilution following CLSI standards. Results were interpreted using CLSI breakpoints where available. Cattle isolates were generally highly susceptible to most antibiotics, except to tetracycline (3.0-12.0% resistance). Low levels of resistance (0-4.0%) were observed for the macrolide antibiotics. Resistance to spectinomycin varied from 0 to 6.0%. In pig isolates similar observations were made. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tulathromycin, tiamulin and tilmicosin was absent or <2%. Trimethoprim/sulfamethoxazole resistance varied from 1.9 to 5.3%, but tetracycline resistance varied from 20.4% in P. multocida to 88.1% in S. suis. For most antibiotics and pathogens the percentage resistance remained unchanged or only increased numerically as compared to that of the period 2002-2006. In conclusion, absence or low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from livestock. Comparison of all antibiotics and organisms was hampered since for almost half of the antibiotics no CLSI-defined breakpoints were available.

  13. Streptococcus henryi sp. nov. and Streptococcus caballi sp. nov., isolated from the hindgut of horses with oligofructose-induced laminitis.

    PubMed

    Milinovich, Gabriel J; Burrell, Paul C; Pollitt, Christopher C; Bouvet, Anne; Trott, Darren J

    2008-01-01

    Four Gram-positive, catalase-negative, coccoid-shaped isolates were obtained from the caecum and rectum of horses with oligofructose-induced equine laminitis. Phenotypic and phylogenetic studies were performed on these isolates. Initial biochemical profiling assigned two of the isolates to Streptococcus bovis. The other two isolates, however, could not be assigned conclusively on the basis of their biochemical profiles. Gene sequence analysis demonstrated that the four new isolates were related most closely to Streptococcus suis based on the 16S rRNA gene and to Streptococcus orisratti based on the manganese-dependent superoxide dismutase gene (sodA). Sequence divergence values from recognized Streptococcus species based on these two genes were >3 and >13%, respectively, for all four isolates. Phylogenetic and phenotypic analyses demonstrated that the four isolates formed two distinct clonal groups that are suggested to represent two novel species of the genus Streptococcus. The names proposed for these organisms are Streptococcus henryi sp. nov. (type strain 126(T) =ATCC BAA-1484(T) =DSM 19005(T)) and Streptococcus caballi sp. nov. (type strain 151(T) =ATCC BAA-1485(T) =DSM 19004(T)).

  14. Brucella suis-Impaired Specific Recognition of Phagosomes by Lysosomes due to Phagosomal Membrane Modifications

    PubMed Central

    Naroeni, Aroem; Jouy, Nicolas; Ouahrani-Bettache, Safia; Liautard, Jean-Pierre; Porte, Françoise

    2001-01-01

    Brucella species are gram-negative, facultatively intracellular bacteria that infect humans and animals. These organisms can survive and replicate within a membrane-bound compartment in phagocytic and nonprofessional phagocytic cells. Inhibition of phagosome-lysosome fusion has been proposed as a mechanism for intracellular survival in both types of cells. However, the biochemical mechanisms and microbial factors implicated in Brucella maturation are still completely unknown. We developed two different approaches in an attempt to gain further insight into these mechanisms: (i) a fluorescence microscopy analysis of general intracellular trafficking on whole cells in the presence of Brucella and (ii) a flow cytometry analysis of in vitro reconstitution assays showing the interaction between Brucella suis-containing phagosomes and lysosomes. The fluorescence microscopy results revealed that fusion properties of latex bead-containing phagosomes with lysosomes were not modified in the presence of live Brucella suis in the cells. We concluded that fusion inhibition was restricted to the pathogen phagosome and that the host cell fusion machinery was not altered by the presence of live Brucella in the cell. By in vitro reconstitution experiments, we observed a specific association between killed B. suis-containing phagosomes and lysosomes, which was dependent on exogenously supplied cytosol, energy, and temperature. This association was observed with killed bacteria but not with live bacteria. Hence, this specific recognition inhibition seemed to be restricted to the pathogen phagosomal membrane, as noted in the in vivo experiments. PMID:11119541

  15. Salt effect of nisin Z isolated from a marine fish on the growth inhibition of Streptococcus iniae, a pathogen of streptococcosis.

    PubMed

    Heo, Won-Seok; Kim, Eun-Young; Kim, Yu-Ri; Hossain, Muhammad Tofazzal; Kong, In-Soo

    2012-02-01

    A bacteriocin-producing Lactococcus lactis subsp. lactis was isolated from the intestine of olive flounder. The bacteriocin was identified as nisin Z. It was active against Gram-positive bacteria. Nisin Z at 3,200 arbitrary units (AU) was more effective in seawater than in PBS; growth of Streptococcus iniae was completely inhibited within 3 h. Nisin Z preparations with 3.5% (w/v) NaCl was the most effective against S. iniae being similar to nisin Z in seawater. Nisin Z is thus a good alternative to antibiotics to prevent streptococcosis caused by S. iniae aquaculture systems.

  16. A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans

    PubMed Central

    Huang, Xuelian; Palmer, Sara R.; Ahn, Sang-Joon; Richards, Vincent P.; Williams, Matthew L.; Nascimento, Marcelle M.

    2016-01-01

    The ability of certain oral biofilm bacteria to moderate pH through arginine metabolism by the arginine deiminase system (ADS) is a deterrent to the development of dental caries. Here, we characterize a novel Streptococcus strain, designated strain A12, isolated from supragingival dental plaque of a caries-free individual. A12 not only expressed the ADS pathway at high levels under a variety of conditions but also effectively inhibited growth and two intercellular signaling pathways of the dental caries pathogen Streptococcus mutans. A12 produced copious amounts of H2O2 via the pyruvate oxidase enzyme that were sufficient to arrest the growth of S. mutans. A12 also produced a protease similar to challisin (Sgc) of Streptococcus gordonii that was able to block the competence-stimulating peptide (CSP)–ComDE signaling system, which is essential for bacteriocin production by S. mutans. Wild-type A12, but not an sgc mutant derivative, could protect the sensitive indicator strain Streptococcus sanguinis SK150 from killing by the bacteriocins of S. mutans. A12, but not S. gordonii, could also block the XIP (comX-inducing peptide) signaling pathway, which is the proximal regulator of genetic competence in S. mutans, but Sgc was not required for this activity. The complete genome sequence of A12 was determined, and phylogenomic analyses compared A12 to streptococcal reference genomes. A12 was most similar to Streptococcus australis and Streptococcus parasanguinis but sufficiently different that it may represent a new species. A12-like organisms may play crucial roles in the promotion of stable, health-associated oral biofilm communities by moderating plaque pH and interfering with the growth and virulence of caries pathogens. PMID:26826230

  17. A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans.

    PubMed

    Huang, Xuelian; Palmer, Sara R; Ahn, Sang-Joon; Richards, Vincent P; Williams, Matthew L; Nascimento, Marcelle M; Burne, Robert A

    2016-01-29

    The ability of certain oral biofilm bacteria to moderate pH through arginine metabolism by the arginine deiminase system (ADS) is a deterrent to the development of dental caries. Here, we characterize a novel Streptococcus strain, designated strain A12, isolated from supragingival dental plaque of a caries-free individual. A12 not only expressed the ADS pathway at high levels under a variety of conditions but also effectively inhibited growth and two intercellular signaling pathways of the dental caries pathogen Streptococcus mutans. A12 produced copious amounts of H2O2 via the pyruvate oxidase enzyme that were sufficient to arrest the growth of S. mutans. A12 also produced a protease similar to challisin (Sgc) of Streptococcus gordonii that was able to block the competence-stimulating peptide (CSP)-ComDE signaling system, which is essential for bacteriocin production by S. mutans. Wild-type A12, but not an sgc mutant derivative, could protect the sensitive indicator strain Streptococcus sanguinis SK150 from killing by the bacteriocins of S. mutans. A12, but not S. gordonii, could also block the XIP (comX-inducing peptide) signaling pathway, which is the proximal regulator of genetic competence in S. mutans, but Sgc was not required for this activity. The complete genome sequence of A12 was determined, and phylogenomic analyses compared A12 to streptococcal reference genomes. A12 was most similar to Streptococcus australis and Streptococcus parasanguinis but sufficiently different that it may represent a new species. A12-like organisms may play crucial roles in the promotion of stable, health-associated oral biofilm communities by moderating plaque pH and interfering with the growth and virulence of caries pathogens.

  18. Identification and Isolation of Brucella suis Virulence Genes Involved in Resistance to the Human Innate Immune System▿

    PubMed Central

    Liautard, Janny; Ouahrani-Bettache, Safia; Jubier-Maurin, Véronique; Lafont, Virginie; Köhler, Stephan; Liautard, Jean-Pierre

    2007-01-01

    Brucella strains are facultative intracellular pathogens that induce chronic diseases in humans and animals. This observation implies that Brucella subverts innate and specific immune responses of the host to develop its full virulence. Deciphering the genes involved in the subversion of the immune system is of primary importance for understanding the virulence of the bacteria, for understanding the pathogenic consequences of infection, and for designing an efficient vaccine. We have developed an in vitro system involving human macrophages infected by Brucella suis and activated syngeneic γ9δ2 T lymphocytes. Under these conditions, multiplication of B. suis inside macrophages is only slightly reduced. To identify the genes responsible for this reduced sensitivity, we screened a library of 2,000 clones of transposon-mutated B. suis. For rapid and quantitative analysis of the multiplication of the bacteria, we describe a simple method based on Alamar blue reduction, which is compatible with screening a large library. By comparing multiplication inside macrophages alone and multiplication inside macrophages with activated γ9δ2 T cells, we identified four genes of B. suis that were necessary to resist to the action of the γ9δ2 T cells. The putative functions of these genes are discussed in order to propose possible explanations for understanding their exact role in the subversion of innate immunity. PMID:17709411

  19. A mouse model for Chlamydia suis genital infection.

    PubMed

    Donati, Manuela; Di Paolo, Maria; Favaroni, Alison; Aldini, Rita; Di Francesco, Antonietta; Ostanello, Fabio; Biondi, Roberta; Cremonini, Eleonora; Ginocchietti, Laura; Cevenini, Roberto

    2015-02-01

    A mouse model for Chlamydia suis genital infection was developed. Ninety-nine mice were randomly divided into three groups and intravaginally inoculated with chlamydia: 45 mice (group 1) received C. suis purified elementary bodies (EBs), 27 (group 2) were inoculated with C. trachomatis genotype E EBs and 27 mice (group 3) with C. trachomatis genotype F EBs. Additionally, 10 mice were used as a negative control. At seven days post-infection (dpi) secretory anti-C. suis IgA were recovered from vaginal swabs of all C. suis inoculated mice. Chlamydia suis was isolated from 93, 84, 71 and 33% vaginal swabs at 3, 5, 7 and 12 dpi. Chlamydia trachomatis genotype E and F were isolated from 100% vaginal swabs up to 7 dpi and from 61 and 72%, respectively, at 12 dpi. Viable C. suis and C. trachomatis organisms were isolated from uterus and tubes up to 16 and 28 dpi, respectively. The results of the present study show the susceptibility of mice to intravaginal inoculation with C. suis. A more rapid course and resolution of C. suis infection, in comparison to C. trachomatis, was highlighted. The mouse model could be useful for comparative investigations involving C. suis and C. trachomatis species. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Infections Associated with Streptococcus intermedius in Children.

    PubMed

    Faden, Howard S

    2016-09-01

    Streptococcus intermedius is a viridans Streptococcus belonging to the Anginosus group. In the past 7 years, it has been associated with abscesses in 48 children, 40% of whom had complicated and/or life-threatening illness. It was the sole pathogen in 35 cases. Seventy-five percent of the infections occurred in winter and spring. None occurred in infants younger than 1 year.

  1. Gene Repertoire Evolution of Streptococcus pyogenes Inferred from Phylogenomic Analysis with Streptococcus canis and Streptococcus dysgalactiae

    PubMed Central

    Lefébure, Tristan; Richards, Vince P.; Lang, Ping; Pavinski-Bitar, Paulina; Stanhope, Michael J.

    2012-01-01

    Streptococcus pyogenes, is an important human pathogen classified within the pyogenic group of streptococci, exclusively adapted to the human host. Our goal was to employ a comparative evolutionary approach to better understand the genomic events concomitant with S. pyogenes human adaptation. As part of ascertaining these events, we sequenced the genome of one of the potential sister species, the agricultural pathogen S. canis, and combined it in a comparative genomics reconciliation analysis with two other closely related species, Streptococcus dysgalactiae and Streptococcus equi, to determine the genes that were gained and lost during S. pyogenes evolution. Genome wide phylogenetic analyses involving 15 Streptococcus species provided convincing support for a clade of S. equi, S. pyogenes, S. dysgalactiae, and S. canis and suggested that the most likely S. pyogenes sister species was S. dysgalactiae. The reconciliation analysis identified 113 genes that were gained on the lineage leading to S. pyogenes. Almost half (46%) of these gained genes were phage associated and 14 showed significant matches to experimentally verified bacteria virulence factors. Subsequent to the origin of S. pyogenes, over half of the phage associated genes were involved in 90 different LGT events, mostly involving different strains of S. pyogenes, but with a high proportion involving the horse specific pathogen S. equi subsp. equi, with the directionality almost exclusively (86%) in the S. pyogenes to S. equi direction. Streptococcus agalactiae appears to have played an important role in the evolution of S. pyogenes with a high proportion of LGTs originating from this species. Overall the analysis suggests that S. pyogenes adaptation to the human host was achieved in part by (i) the integration of new virulence factors (e.g. speB, and the sal locus) and (ii) the construction of new regulation networks (e.g. rgg, and to some extent speB). PMID:22666370

  2. The immune response against Chlamydia suis genital tract infection partially protects against re-infection.

    PubMed

    De Clercq, Evelien; Devriendt, Bert; Yin, Lizi; Chiers, Koen; Cox, Eric; Vanrompay, Daisy

    2014-09-25

    The aim of the present study was to reveal the characteristic features of genital Chlamydia suis infection and re-infection in female pigs by studying the immune response, pathological changes, replication of chlamydial bacteria in the genital tract and excretion of viable bacteria. Pigs were intravaginally infected and re-infected with C. suis strain S45, the type strain of this species. We demonstrated that S45 is pathogenic for the female urogenital tract. Chlamydia replication occurred throughout the urogenital tract, causing inflammation and pathology. Furthermore, genital infection elicited both cellular and humoral immune responses. Compared to the primo-infection of pigs with C. suis, re-infection was characterized by less severe macroscopic lesions and less chlamydial elementary bodies and inclusions in the urogenital tract. This indicates the development of a certain level of protection following the initial infection. Protective immunity against re-infection coincided with higher Chlamydia-specific IgG and IgA antibody titers in sera and vaginal secretions, higher proliferative responses of peripheral blood mononuclear cells (PBMC), higher percentages of blood B lymphocytes, monocytes and CD8⁺ T cells and upregulated production of IFN-γ and IL-10 by PBMC.

  3. The Importance of TLR2 and Macrophages in Modulating a Humoral Response after Encountering Streptococcus pneumoniae

    DTIC Science & Technology

    2008-03-26

    receptor in recognizing important moieties on gram -positive bacteria including peptidoglycan , lipoproteins and lipoteichoic acid (67-71). Originally TLR2...Pathogen associated molecular patterns PerM-Peritoneal macrophage PC-phosphorylcholine PGN- Peptidoglycan Pn-Streptococcus pneumoniae Pn14-Streptococcus...pathogenesis Streptococcus pneumoniae (Pn), also referred to as pneumococcus, is a gram - positive anaerobic bacterium and an important cause of many

  4. Differential expression of putative adhesin genes of Actinobacillus suis grown in in vivo-like conditions.

    PubMed

    Bujold, Adina R; Labrie, Josée; Jacques, Mario; MacInnes, Janet I

    2016-11-15

    Actinobacillus suis is an opportunistic pathogen that resides in the tonsils of the soft palate of swine. Unknown stimuli can cause this organism to invade the host, resulting in septicaemia and sequelae including death. To better understand its pathogenesis, the expression of several adhesin genes was evaluated by semi-quantitative real-time PCR in A. suis grown in conditions that mimic the host environment, including different nutrient and oxygen levels, exponential and stationary phases of growth, and in the presence of the stress hormone epinephrine. Fifty micromolar epinephrine did not affect the growth rate or expression of A. suis adhesin genes, but there was a significant growth phase effect for many genes. Most adhesin genes were also differentially expressed during anoxic static growth or aerobic growth, and in this study, all genes were differentially expressed in either exponential or stationary phase. Based on the time*treatment interactions observed in the anoxic study, a model of persistence of A. suis in the host environment in biofilm and planktonic states is proposed. Biofilm dynamics were further studied using wild type and isogenic mutants of the type IVb pilin (Δ flp1), the OmpA outer membrane protein (ΔompA), and the fibronectin-binding (ΔcomE1) genes. Disruption of these adhesin genes affected the early stages of biofilm formation, but in most cases, biofilm formation of the mutant strains was similar to that of the wild type by 24h of incubation. We postulate that other adhesins may have overlapping functions that can compensate for those of the missing adhesins. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Human Streptococcus agalactiae isolate in Nile tilapia (Oreochromis niloticus).

    PubMed

    Evans, Joyce J; Klesius, Phillip H; Pasnik, David J; Bohnsack, John F

    2009-05-01

    Streptococcus agalactiae, the Lancefield group B streptococcus (GBS) long recognized as a mammalian pathogen, is an emerging concern with regard to fish. We show that a GBS serotype Ia multilocus sequence type ST-7 isolate from a clinical case of human neonatal meningitis caused disease and death in Nile tilapia (Oreochromis niloticus).

  6. Integrated analysis neurimmiRs of tilapia (Oreochromis niloticus) involved in immune response to Streptococcus agalactiae, a pathogen causing meningoencephalitis in teleosts.

    PubMed

    Wang, Bei; Gan, Zhen; Wang, Zhongliang; Yu, Dapeng; Lin, Ziwei; Lu, Yishan; Wu, Zaohe; Jian, Jichang

    2017-02-01

    MicroRNAs (miRNAs) are a class of noncoding RNA molecules and play important roles in a wide spectrum of biological processes, including in immune response. Recent years have witnessed considerable amount of research interest in studies on miRNA-mediated modulation gene function during neuroinflammation. Here, we evaluated Streptococcus agalactiae infected tilapia (Oreochromis niloticus) brain for the expression profile of miRNAs, potential functions and their correlation with genes involved in inflammatory pathways. A total of 1981 miRNAs were identified, including in 486 miRNAs which have homologues in the currently available databases and 1945 novel miRNAs. The expression levels of 547 miRNAs were significantly altered at 6 h-48 h post-bacterial infection, and these miRNAs were therefore classified as differentially expressed tilapia miRNAs. Real-time PCR were implemented for 14 miRNAs co-expressed in five samples, and agreement was confirmed between the high-throughput sequencing and real-time PCR data. For the 486 differentially expressed miRNAs target 41,820 genes. GO and KEGG enrichment analysis revealed that some target genes of miRNAs were grouped mainly into the categories of apoptotic, signal pathwayand immune response. This is the first report of comprehensive identification of teleost miRNAs being differentially regulated in brain in normal conditions relating to bacterial infection. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Molecular population genetic evidence of horizontal spread of two alleles of the pyrogenic exotoxin C gene (speC) among pathogenic clones of Streptococcus pyogenes.

    PubMed Central

    Kapur, V; Nelson, K; Schlievert, P M; Selander, R K; Musser, J M

    1992-01-01

    It has recently been demonstrated that the bacteriophage-borne gene (speC) encoding pyrogenic exotoxin C is harbored by phylogenetic lineages representing virtually the entire breadth of genomic differentiation present in the species Streptococcus pyogenes (J. M. Musser, A. R. Hauser, M. H. Kim, P. M. Schlievert, K. Nelson, and R. K. Selander, Proc. Natl. Acad. Sci. USA 88:2668-2672, 1991). To determine whether the speC genes occurring in association with divergent chromosomal genotypes (clones) are identical or represent a group of allelic variants, we sequenced speC from 23 S. pyogenes strains representing 15 clones identified by multilocus enzyme electrophoresis. Two alleles of speC are present in natural populations, and each allele occurs in clones that are well differentiated in overall chromosomal character; in one case, isolates of a single clone had different speC alleles. We interpret these patterns of toxin allele-clone distribution as evidence of occasional episodes of speC horizontal dissemination, presumably by bacteriophage-mediated gene transfer and recombination. Images PMID:1500157

  8. First Human Case of Meningitis and Sepsis in a Child Caused by Actinobacillus suis or Actinobacillus equuli

    PubMed Central

    Montagnani, Carlotta; Pecile, Patrizia; Moriondo, Maria; Petricci, Patrizia; Becciani, Sabrina; Chiappini, Elena; Indolfi, Giuseppe; Rossolini, Gian Maria; de Martino, Maurizio

    2015-01-01

    We report the first human case of meningitis and sepsis caused in a child by Actinobacillus suis or A. equuli, a common opportunistic pathogen of swine or horses, respectively. Identification was performed by matrix-assisted laser desorption ionization–time of flight mass spectrometry and real-time PCR assay. A previous visit to a farm was suspected as the source of infection. PMID:25878346

  9. In Vitro Brucella suis Infection Prevents the Programmed Cell Death of Human Monocytic Cells

    PubMed Central

    Gross, Antoine; Terraza, Annie; Ouahrani-Bettache, Safia; Liautard, Jean-Pierre; Dornand, Jacques

    2000-01-01

    During the complex interaction between an infectious agent and a host organism, the pathogen can interfere with the host cell's programmed death to its own benefit. Induction or prevention of host cell apoptosis appears to be a critical step for determining the infection outcome. Members of the gram-negative bacterial genus Brucella are intracellular pathogens which preferentially invade monocytic cells and develop within these cells. We investigated the effect of Brucella suis infection on apoptosis of human monocytic phagocytes. The present study provides evidence that Brucella infection inhibited spontaneously occurring apoptosis in human monocytes. Prevention of monocyte apoptosis was not mediated by Brucella lipopolysaccharide and required bacterial survival within infected cells. Both invaded and noninvaded cells were protected, indicating that soluble mediators released during infection were involved in the phenomenon. Analysis of Brucella-infected monocytes revealed specific overexpression of the A1 gene, a member of the bcl-2 family implicated in the survival of hematopoietic cells. Brucella infection also rendered macrophage-like cells resistant to Fas ligand- or gamma interferon-induced apoptosis, suggesting that Brucella infection protected host cells from several cytotoxic processes occurring at different steps of the immune response. The present data clearly show that Brucella suis modulated the monocyte/macrophage's apoptotic response to the advantage of the pathogen, thus preventing host cell elimination. This might represent a strategy for Brucella development in infected hosts. PMID:10603407

  10. Quantification of bovine oxylipids during intramammary Streptococcus uberis infection

    USDA-ARS?s Scientific Manuscript database

    Streptococcus uberis mastitis results in severe mammary tissue damage in dairy cows due to uncontrolled inflammation. Oxylipids are potent lipid mediators that orchestrate pathogen-induced inflammatory responses, however, changes in oxylipid biosynthesis during S. uberis mastitis are unknown. Thus, ...

  11. Are Tilapia Infected with Gyrodactylus More Susceptible to Streptococcus?

    USDA-ARS?s Scientific Manuscript database

    Streptococcus iniae and Gyrodactylus niloticus are two common pathogens of cultured Nile tilapia, Oreochromis niloticus. We studied concurrent infection of tilapia by G. niloticus and S. iniae and evaluated whether parasitism in tilapia with Gyrodactylus increased susceptibility and mortality follo...

  12. Neonatal Streptococcus pneumoniae septicemia and meningitis. A case report.

    PubMed

    Di Nello, C H; Chaisilwattana, P; Fagnant, R J; Monif, G R

    1990-03-01

    Neonatal septicemia/meningitis from Streptococcus pneumoniae occurred in a 36-hour-old infant. The mother had no overt evidence of infection. This case illustrates the pathogenic potential of this common bacterium in the neonate.

  13. Carriage of Streptococcus pneumoniae and Other Respiratory Bacterial Pathogens in Low and Lower-Middle Income Countries: A Systematic Review and Meta-Analysis

    PubMed Central

    Adegbola, Richard A.; DeAntonio, Rodrigo; Hill, Philip C.; Roca, Anna; Usuf, Effua; Hoet, Bernard; Greenwood, Brian M.

    2014-01-01

    Background Infection with Streptococcus pneumoniae is a major cause of childhood morbidity and mortality worldwide, especially in low income countries where pneumococcal conjugate vaccines (PCVs) are still underused. In countries where PCVs have been introduced, much of their efficacy has resulted from their impact on nasopharyngeal carriage in vaccinated children. Understanding the epidemiology of carriage for S. pneumoniae and other common respiratory bacteria in developing countries is crucial for implementing appropriate vaccination strategies and evaluating their impact. Methods and Findings We have systematically reviewed published studies reporting nasopharyngeal or oropharyngeal carriage of S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and Neisseria meningitidis in children and adults in low and lower-middle income countries. Studies reporting pneumococcal carriage for healthy children <5 years of age were selected for a meta-analysis. The prevalences of carriage for S. pneumoniae, H. influenzae, and M. catarrhalis were generally higher in low income than in lower-middle income countries and were higher in young children than in adults. The prevalence of S. aureus was high in neonates. Meta-analysis of data from young children before the introduction of PCVs showed a pooled prevalence estimate of 64.8% (95% confidence interval, 49.8%–76.1%) in low income countries and 47.8% (95% confidence interval, 44.7%–50.8%) in lower-middle income countries. The most frequent serotypes were 6A, 6B, 19A, 19F, and 23F. Conclusions In low and lower-middle income countries, pneumococcal carriage is frequent, especially in children, and the spectrum of serotypes is wide. However, because data are limited, additional studies are needed to adequately assess the impact of PCV introduction on carriage of respiratory bacteria in these countries. PMID:25084351

  14. Haemolytic activity of the Streptococcus milleri group' and relationship between haemolysis restricted to human red blood cells and pathogenicity in S. intermedius.

    PubMed

    Jacobs, J A; Schot, C S; Schouls, L M

    2000-01-01

    A collection of 297 clinically documented 'Streptococcus milleri' strains, identified to the genotype level by 16S rRNA gene hydridisation, was screened for haemolysis of human and animal red blood cells. Forty-nine strains (65%) of the S. intermedius genotype displayed haemolysis restricted to human blood; they were named 'exclusive human haemolytic' (EHH) S. intermedius strains. The 26 remaining S. intermedius strains were named S. intermedius non-EHH strains. Quantitative studies on the haemolysis indicated that intermedilysin was the factor involved. The S. intermedius EHH strains represented the S. intermedius phenotype, whereas the S. intermedius non-EHH strains were phenotypically characteristic of S. constellatus. The complete 16S rRNA sequences of the S. intermedius EHH strains exhibited identity with S. intermedius strains ATCC 27335 (= NCDO 2227, NCTC 11324); the 16S rRNA sequences of the S. intermedius