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Two surveys were conducted to ascertain the effect which Staphylococcus aureus has on resident flora and on skin of patients with eczema. Forty paired sites, normal and lesions, were sampled from 32 patients with chronic lichenified atopic dermatitis, and 162 sites covering the entire body of a patient with an acute flare of chronic atopic dermatitis were examined. In the first study, 34 lesions (85%) carried S. aureus, and 85% of these positive samples supported greater than 10(4) colony-forming units (CFU) of total aerobic bacteria/cm2. About 55% of normal sites carried S. aureus with 18% of such samples supporting greater than 10(4) CFU/cm2 total aerobic bacteria. Normal sites carried fewer but more diverse flora than lesions. The composition of flora on lesion sites was mainly S. aureus or S. epidermidis biotype 1, or both. At densities greater than 10(7) CFU/cm2, S. aureus constituted almost 100% of the total aerobic bacterial flora. The total body survey of the single eczema patient yielded similar results. Evidence supports the hypotheses that (1) S. aureus is able to exploit the environment of eczematous lesions and to influence the composition of cohabiting aerobic skin bacteria, and (2) its inhabitation of normal appearing sites is transitory.

Aerobic flora from wet-occluded forearms of six volunteers was sampled the day before treatment, on the 3rd day when dressings were removed, and daily, when possible, for 8 days thereafter. Erythema was not present. All bacterial colonies appearing on appropriate dilution plates were identified with the aid of a replica-plating technique. Flora of each individual increased to over 10-4 colony-forming units/cm2 as a result of wet-occlusion, but counts rapidly fell by about 10-2 units once dressings were removed. Although similar types of bacteria were found on all subjects, the composition of each individual's flora during the recovery response appeared to be unique. Enterobacteriaceae were found on half the subjects with Enterobacter aerogenes being the most successful colonizer. Besides the expected presence of Baird-Parker Staphylococcus subgroup II, high numbers of subgroup IV and some colonies of subgroup III were also observed. Almost all cutaneous diphtheroids were lipophilic and lipolytic.