Dermatitis in nude mice (nu/nu) associated with Staphylococcus pyogenes

Nude mice (nu/nu on BALB/cAn background), maintained under conventional conditions, developed an acute moist dermatitis of the nose and occasionally the ears, with heavy contamination with Staphylococcus pyogenes. Only homozygotes over 10 weeks old were affected. Treatment with parenteral ampicillin or oral oxytetracycline was ineffective. Other conditions associated with the same organism were conjunctivitis and periorbital abscesses.