A study of skin diseases in dogs and cats. VI. Microflora of the major canine pyodermas.

From 40 dogs with pyoderma swabs from areas with representative lesions were examined bacteriologically. Staph. aureus was found in 98% of the areas, beta-hemolytic streptococci in 30%, and Gram-negative organisms, mainly Proteus spp., in 30% (Table I). Pure infection with Staph. aureus was found in 55% of the areas. Staph. aureus and beta-hemolytic streptococci were found in 15%, Staph. aureus and Gram-negative organisms in 15%, Staph. aureaus and beta-hemolytic streptococci as well as Gram-negative organisms in 13%, and beta-hemolytic streptococci and Gram-negative organisms in 3% (Table II). Compared to normal and eczematous skin areas, Staph. aureus was found more often, and in greater numbers, in areas with pyoderma, whereas micrococci, alpha-hemolytic streptococci, and Acinetobacter spp. were rarer. Gram-negative organisms such as Proteus spp., E. coli, and Pseudomonas spp. were found with equal frequency in eczema and pyoderma, while beta-hemolytic streptococci were almost exclusively associated with suppurative lesions (Tables IV and V).