Comparison of production of Staphylococcus intermedius exotoxin among clinically normal dogs, atopic dogs with recurrent pyoderma, and dogs with a single episode of pyoderma

Abstract

Objective - To determine whether exotoxin production by Staphylococcus intermedius is an important factor in recurrence of pyoderma in atopic dogs. Design - Prospective clinical study. Animals - 30 client-owned dogs (10 clinically normal dogs, 10 atopic dogs with recurrent pyoderma, and 10 dogs with a single episode of pyoderma). Procedure - Specimens for bacterial culturing were obtained from a pustule or papule of affected dogs or from skin of clinically normal dogs. Staphylococcus intermedius was isolated and processed. Supernatants were analyzed for staphylococcal exotoxins. Types of lesions and severity of pruritus were assessed for each dog. Results - Exotoxins A and C were detected in S intermedius isolated from 1 clinically normal dog. In the atopic group, exotoxin C was isolated from 1 dog, exotoxins A and C were isolated from 1 dog, and exotoxin C and toxic shock syndrome toxin-1 were isolated from 1 dog. Exotoxins were isolated from 2 dogs with a single episode of pyoderma (exotoxin C, 1 dog; exotoxins A and C, 1 dog). Lesion types and severity of pruritus varied greatly among dogs with pyoderma and were not associated with detection of exotoxin or type of exotoxin. Clinical Implications - Exotoxins were identified from few isolates of S intermedius, and we did not observe an association between type of lesions or severity of pruritus and detection of exotoxins. Production of exotoxin by S intermedius does not play a role in the recurrent nature of pyoderma in atopic dogs or on type of lesion or severity of pruritus associated with pyoderma.