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 fibronectinbinding 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.Streptococcus suis serotype 2 is an important invasive porcine pathogen worldwide. It also causes meningitis and other diseases in humans. Processing of pork is considered to be a major risk factor of this zoonosis (3). In pigs, septicemia, meningitis, polyarthritis, polyserositis, and pneumonia are common clinical manifestations. These diseases have been reproduced experimentally by infections with S. suis serotype 2. In addition to epidemiological data, experimental infections demonstrated that wild-type serotype 2 strains, which express a 136-kDa muramidase-released protein (MRP) and an 80-kDa extracellular factor (EF), are highly virulent, in contrast to MRP Ϫ EF Ϫ serotype 2 strains from Europe (32, 35). Smith et al. (27) previously showed that the capsule of S. suis protects against phagocytosis. Other factors such as suilysin and the fibronectin-and fibrinogen-binding protein of S. suis (FBPS) may contribute to the pathogenesis of S. suis (1, 9, 19), but so far, the capsule is the only major virulence factor to be identified (27).In other streptococci such as Streptococcus pyogenes and Streptococcus dysgalactiae, a number of large surface-associated proteins, including SfbI, serum opacity factor (SOF), and fibronectin-binding prot...

ABSTRACTBacterial isolates from frogs were phenotypically identified asOchrobactrum anthropi, but 16S rRNA sequencing showed up to 100% identity withBrucella inopinata. Further analysis ofrecA,omp2a,omp2b,bcsp31, and IS711and multilocus sequence analysis (MLSA) verified a close relationship withBrucella, suggesting the isolates may actually represent novel members of this growing genus of zoonotic pathogens.

Summary Canine cutaneous histiocytoma is a benign epidermal neoplasm of Langerhans cell origin, which usually displays spontaneous regression. Based on the degree of lymphocytic infiltration, 30 histiocytomas were classified into four groups representing different stages of tumour regression. To elucidate further the mechanisms of the antitumour immune response CD3+, CD21+, CD4+, CD8+ and myeloid/histiocyte antigen+ inflammatory cells were differentiated by immunohistochemistry and quantified. In addition, the number of apoptotic cells was detected using the TdT‐mediated biotin–dUTP nick‐end labelling (TUNEL) method. Furthermore, the expression of interleukin‐ (IL‐2), IL‐12(p40), tumour necrosis factor‐α (TNF‐α), interferon‐γ (IFN‐γ), IL‐10 and transforming growth factor‐β (TGF‐β) as well as inducible nitric oxid synthase (iNOS) mRNA was determined by reverse transcription–polymerase chain reaction (RT–PCR). Phenotyping of inflammatory cells revealed a significantly increased infiltration of all lymphocyte subsets and myeloid/histiocytic cells with the onset of tumour regression. The latter was significantly correlated to up‐regulation of IL‐2, TNF‐α, IFN‐γ and iNOS mRNA expression. Expression of remaining cytokines and percentage of apoptotic cells showed no group‐specific changes. The results indicate an initial infiltration of CD4+ T cells followed by increased expression of Th1 cytokines and recruitment of antitumour effector cells as the principal mechanism for tumour regression. Canine cutaneous histiocytoma is a unique example for an effective immune response in a naturally occurring neoplasm derived from epidermal Langerhans cells and might represent a valuable animal model to investigate tumour immunity.

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Background Trueperella pyogenes is a worldwide known bacterium causing mastitis, abortion and various other pyogenic infections in domestic animals like ruminants and pigs. In this study we represent the first case report of three unusual fatal infections of Grey Slender Lorises caused by Trueperella pyogenes. Meanwhile, this study represents the first in-depth description of the multilocus sequence analysis (MLSA) on T. pyogenes species. Case presentationThree Trueperella pyogenes were isolated from three different Grey Slender Lorises, which died within a period of two years at Frankfurt Zoo (Frankfurt am Main - Germany). The three Grey Slender Loris cases were suffering from severe sepsis and died from its complication. During the bacteriological investigation of the three cases, the T. pyogenes were isolated from different organisms in each case. The epidemiological relationship between the three isolates could be shown by four genomic DNA fingerprint methods (ERIC-PCR, BOX-PCR, (GTG)5-PCR, and RAPD-PCR) and by multilocus sequence analysis (MLSA) investigating four different housekeeping genes (fusA-tuf-metG-gyrA). ConclusionIn this study, we clearly showed by means of using three different rep-PCRs, by RAPD-PCR and by MLSA that the genomic fingerprinting of the investigated three T. pyogenes have the same clonal origin and are genetically identical. These results suggest that the same isolate contaminated the animal’s facility and subsequently caused cross infection between the three different Grey Slender Lorises. To the best of our knowledge, this is the first epidemiological approach concentrating on T. pyogenes using MLSA.