Pathogenicity of four strains of staphylococci isolated from chickens with clinical tenosynovitis.

Four strains of staphylococci of different phage patterns (two principal and two minor phage types) associated with naturally occurring tenosynovitis were studied for their virulence for chickens and tropism for tendon tissue. There were significant differences in virulence between the principal and minor phage types of Staphylococcus aureus. Infection with the principal phage types produced a generalised septicaemic disease and no specific tropism of the bacteria for tendon tissue although there were gross and histopathological changes in tendons and tendon sheaths indistinguishable from those in naturally occurring tenosynovitis. However, the patho-genesis of the disease observed in the experimental infections was different to that considered to occur in natural cases of tenosynovitis and provided further indirect evidence for the secondary nature of the staphylococcal infection in tenosynovitis.