Streptococcus canis arthritis in a cat breeding colony.

This is the first description of a pathologic condition--arthritis in cats affecting mainly one joint, i.e. monarthritis--caused by Streptococcus canis (S. canis), of the Lancefield serologic group G. Six cases were recorded in a closed cat breeding colony during a 6 month period in 1988, and one additional case in 1990. Therapy with penicillin and streptomycin led to full recovery in four of six cases. The bacterium had been detected from different purulent processes sporadically--including one case of purulent arthritis in 1982--as a nosocomial infection since 1980, the year the breeding colony was established. A possible genetic predisposition (high inbreeding) may have contributed to the accumulation of the six cases in 1988. Although S. canis was isolated in mouse, rat, rabbit and dog, cat and man seem to be more frequently affected. There are some similarities between S. canis-arthritis in cat and man.