Protection of pigs against challenge with virulent Streptococcus suis serotype 2 strains by a muramidase-released protein and extracellular factor vaccine.

The efficacy of a muramidase-released protein (MRP) and extracellular factor (EF) vaccine in preventing infection and disease in pigs challenged either with a homologous or a heterologous Streptococcus suis serotype 2 strain (MRP+EF+) was compared with the efficacy of a vaccine containing formalin-killed bacterin of S. suis serotype 2 (MRP+EF+). The enhancement of the immune response by different adjuvants (a water-in-oil emulsion [WO] and an aluminium hydroxide-based adjuvant [AH]) and their side effects were also studied.

Distribution of capsular types and production of muramidase-released protein (MRP) and extracellular factor (EF) of Streptococcus suis strains isolated from diseased pigs in seven European countries.

Streptococcus suis strains (n=411), isolated from diseased pigs in seven European countries were serotyped using specific antisera against serotype 1 to 28, and were phenotyped on the basis of their muramidase-released-protein (MRP) and extracellular-factor protein (EF) production. Overall, S. suis serotype 2 appeared to be most prevalent (32%), followed by serotype 9 (20%) and serotype 1 (12%).

Detection of virulent strains of Streptococcus suis type 2 and highly virulent strains of Streptococcus suis type 1 in tonsillar specimens of pigs by PCR.

We developed a PCR assay for the rapid and sensitive detection of virulent Streptococcus suis type 2 and highly virulent S. suis type 1 in tonsillar specimens from pigs. The PCR primers were based on the sequence of the gene encoding the EF-protein of virulent S.

Cell tropism of Staphylococcus aureus in bovine mammary gland cell cultures.

Staphylococcus aureus is one of the most important pathogens of the bovine mammary gland. The interaction of S. aureus with cells of the bovine mammary gland is considered to play an essential role in the pathogenesis.

Low prevalence of antibodies against the zoonotic agents Brucella abortus, Leptospira spp., Streptococcus suis serotype II, hantavirus, and lymphocytic choriomeningitis virus among veterinarians and pig farmers in the southern part of The Netherlands.

Serum samples from 102 veterinarians and 191 pig farmers from the southern part of the Netherlands were investigated for antibodies against Brucella abortus, Leptospira spp, Streptococcus suis serotype II, Hantavirus (HV), and lymphocytic choriomeningitis virus (LCMV). All samples were collected in 1993 and stored until this study was performed. The prevalence of antibodies against B.

The presence of muramidase released protein and extracellular factor protein in various serotypes of Streptococcus suis isolated from diseased and healthy pigs in Spain.

A total of 142 strains from different serotypes of Streptococcus suis isolated in Spain from diseased pigs (88 strains) and healthy carrier pigs (54 strains) were studied for the presence of a muramidase released protein (MRP) and an extracellular factor (EF). The following five phenotypes: MRP+EF+, MRP+EF-, MRP-EF+, MRP+EF* and MRP*EF- were detected. A high percentage of S.

Measurement of Actinomyces pyogenes specific antibodies in bovine blood samples by an enzyme-linked immunosorbent assay.

In the present investigation Actinomyces pyogenes specific antigens caused an antibody response in the host. This could be determined by two enzyme-linked immunosorbent assays (ELISA) using cell extracts and a haemolysin preparation as antigens. An increased antibody titre was detectable in the sera of cows vaccinated with culture supernatants of A.

Virulence of Streptococcus suis type 2 for mice and pigs appeared host-specific.

A murine model for Streptococcus suis infection in pigs was validated by inoculating groups of 5 BALB/c and 5 CF1 mice with 10(7) CFU/ml of 13 different S. suis serotype 2 strains. The pathogenicity of these strains had been established in a standardized pig model of S.

Production of virulence-related proteins by Canadian strains of Streptococcus suis capsular type 2.

The production of muramidase-released protein (MRP), extracellular protein factor (EF) and hemolysin (suilysin) by 101 Canadian field strains of Streptococcus suis capsular type 2 is described. Most strains (72%) isolated from diseased pigs were MRP-EF- and only 1 strain was MRP+EF+. This strain was also the only 1 to produce the hemolysin.

Virulent strains of Streptococcus suis serotype 2 and highly virulent strains of Streptococcus suis serotype 1 can be recognized by a unique ribotype profile.

The ribotype profiles of 42 different Streptococcus suis strains were studied. These strains belonged to five serotypes and differed in their virulence for pigs as well as in the expression of the muramidase-released protein and the extracellular protein factor. For the ribotyping, chromosomal DNAs were digested with EcoRI and were hybridized with a 1,066-bp ribosomal DNA probe.

Mutants of Streptococcus suis types 1 and 2 impaired in expression of muramidase-released protein and extracellular protein induce disease in newborn germfree pigs.

The contribution of muramidase-released protein (MRP) and extracellular factor (EF) to the virulence of Streptococcus suis type 1 and 2 infections was studied. For that aim, we constructed mutants of S. suis types 1 and 2 by inactivating the genes encoding MRP and EF.

Characterization of virulence of the Streptococcus suis serotype 2 reference strain Henrichsen S 735 in newborn gnotobiotic pigs.

Strain Henrichsen S 735 (NCTC 10234) of Streptococcus suis serotype 2 reference and three other such strains (strains S 4005, S 3921 and T 141) were tested for virulence by inoculating pigs intranasally and intravenously. The taxonomical properties of each strain were determined. Phenotypes were determined by Western blotting based on MRP and EF protein expression and genotypes were determined by Southern hybridization analysis of the mrp and epf genes.

Prevalence of various phenotypes of Streptococcus suis isolated from swine in the U.S.A. based on the presence of muraminidase-released protein and extracellular factor.

The present study describes the prevalence of muraminidase-released protein (MRP) and extracellular factor (EF) proteins associated with virulence of Streptococcus suis serotype 2 from a collection of USA strains. Sixty-six strains belonging to serotypes 1, 2, 3, 4, 7, and 10, were analyzed with a set of double antibody sandwich ELISAs and Western blots. Nineteen of 34 serotype 2 strains from cases of swine meningitis had the MRP+EF+ phenotype.

High-efficiency transformation and gene inactivation in Streptococcus suis type 2.

An efficient electrotransformation system for Streptococcus suis type 2 is described. It is demonstrated that vectors based on the broad-host-range plasmid pWVO1 replicate in S. suis type 2.

[Streptococcal infections as cause of death in pigs brought in for necropsy].

Research was carried out into the prevalence of streptococcal types isolated from pigs that died of septicaemia, meningo-encephalitis, endocarditis, and pneumonia and which were brought in for investigation from 1 january 1988 to 31 December 1991. Cultures were prepared from the liver, spleen, kidneys, and brains of all animals and from the heart valves, joints, bronchi, and lungs of animals with pathological changes. The results are presented in six tables.

Repeats in an extracellular protein of weakly pathogenic strains of Streptococcus suis type 2 are absent in pathogenic strains.

Streptococcus suis type 2 strains that are pathogenic for pigs produce a 110-kDa extracellular protein factor (EF). Nonpathogenic and weakly pathogenic strains do not produce EF or produce a protein (EF*) that is immunologically related to EF. To study the pathogenesis of S.

Discrimination between virulent and nonvirulent Streptococcus suis type 2 strains by enzyme-linked immunosorbent assay.

Discrimination between virulent and nonvirulent strains of Streptococcus suis type 2 will allow proper diagnosis of diseased pigs and the identification of carrier pigs. To discriminate between virulent and nonvirulent strains, we developed two double antibody sandwich (DAS) enzyme-linked immunosorbent assays (ELISA) using specific monoclonal antibodies directed against two virulence markers of S. suis type 2.

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

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.

Virulence of Streptococcus suis type 2 strains in newborn germfree pigs depends on phenotype.

To determine whether the virulence of Streptococcus suis type 2 is associated with the phenotype of the strain, we infected newborn germfree pigs with 10 strains of S. suis type 2 categorized by three phenotypes. In an earlier study, the phenotypes were distinguished by the presence or absence of the muramidase-released protein (MRP) and an extracellular factor (EF) and were designated MRP+ EF+, MRP+ EF- and MRP- EF-.

Identification of two proteins associated with virulence of Streptococcus suis type 2.

The protein profiles of various cell fractions of 180 strains of Streptococcus suis type 2, which were isolated from diseased pigs, from healthy pigs when they were slaughtered, and from human patients, were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The isolates from diseased pigs contained two proteins that were absent in most of the isolates from healthy pigs. One of these proteins was a 136-kDa protein that was previously identified as the muramidase-released protein (MRP).

Effect of damage to the teat end on the experimental induction of mastitis in dry cows with Corynebacterium pyogenes.

The teat ends of 12 dry cows were contaminated with Corynebacterium pyogenes. To determine whether a pre-existing (an)aerobic bacterial infection of the udder was a predisposing factor for a C pyogenes mastitis they included infected and uninfected quarters. Anaerobic bacteria could not be found and mastitis was not induced.

Differences in virulence between two strains of Streptococcus suis type II after experimentally induced infection of newborn germ-free pigs.

Fifteen newborn germ-free pigs were inoculated with 2 strains, D-282 and T-15, of Streptococcus suis type II. Some pigs also were preinoculated with Bordetella bronchiseptica, which successfully predisposed them to S suis infection. The 2 streptococcal strains were differentiated by muramidase treatment, which released certain high molecular-weight proteins, termed muramidase-released proteins (MRP), from the cell wall of strain D-282, but not from the cell wall of strain T-15.