Sensitivity to antibacterials of Staphylococcus aureus isolated from different types of skin infections.

We examined the antibacterial susceptibility of Staphylococcus aureus isolated from several types of skin infections, which were classified into four groups: (i) impetigo, (ii) folliculitis, (iii) atopic dermatitis and eczema and (iv) ulcers and decubitus. The 50% minimal inhibitory concentration (MIC50) of the antibacterial agents was 3.13 micrograms/ml or lower, except that of gentamicin with isolates from the impetigo groups (25 micrograms/ml). The MIC90 of gentamicin was 50 micrograms/ml or more for isolates from all four groups. The isolates from the ulcers and decubitus group showed multiple resistance against antibacterial agents. The frequency of methicillin-resistant S. aureus was low, but was highest, at 25%, in the isolates from the ulcers and decubitus group. Few isolates from the atopic dermatitis and eczema group were resistant, and there was little difference in antibacterial resistance between isolates from atopic dermatitis and eczema.