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*Non-motile
*Non-motile
*Catalase negative, oxidase negative, coagulase positive
*Catalase negative, oxidase negative, coagulase positive
*Grow on nutrient agar; growth enhanced by addition of blood or serum
*Grow on nutrient agar; growth enhanced by addition of blood or serum
*Small colonies with incomplete haemolysis in 48 hours
*Small colonies with incomplete haemolysis in 48 hours
*Hydrogen sulphide sormed along stab line in TSI agar
*Hydrogen sulphide formed as black central line in TSI agar
*Growth over wide rangs of temperatures and pH
*Growth over wide rangs of temperatures and pH
===Identification and diagnosis===
*Isolates from acute infections produce smooth colonies; 1.5mm diamteter, convex and circular with even edges
*Isolates from chronic infections produce rough colonies; larger, flat and opaque colonieswith irregular edges
*Biochemical tests
*Serotypying according to a heat-stable peptidoglycan extracted from the cell wall
*Virulence testing in lab animals
*PCR for detection of virulent isolates
===Pathogenesis and pathogenicity===
*Route of infection: ingestion from pig faeces
*Entry via tonsils, skin or mucous membranes
*Capsule prevents phagocytosis
*Adhere to endothelial cells
*Produce neurominidase which enhances cell penetration
*Septicaemia with vascular damage
*Swelling of endothelial cells, monocyte adherence to vascular walls and hyaline microthrombus formation
*Bacteria localise in synovia of joints and on heart valves during bacteraemia and cause chronic lesions
*Host immune response to persistent bacterial antigens causes long-term damage to the joints
===Clinical infections===