Qualitative and quantitative investigations on the resident bacterial skin flora in healthy persons and in the non-affected skin of patients with seborrheic Eczema.

The composition of the aerobic and anaerobic bacterial skin flora was investigated quantitatively and qualitatively in 25 patients with seborrheic eczema (SE) and in 35 healthy persons. In SE patients, the geometric mean count for propionibacteria in the pilosebaceous ducts of the forehead was reduced to a statistically significant extent in comparison with the control group. There was the same tendency with regard to the geometric mean count of the superficial anaerobic bacterial flora of the back, whereas the geometric mean counts of the coagulase-negative staphylococci were the same in the two groups. These results may explain earlier findings of a reduction of free fatty acids in the surface lipids in SE patients. According to the results of differentiation in 295 propionibacteria and 157 micrococcaceae, 7 biotypes and 10 phage types of propionibacteria which were so far unknown could be demonstrated. Significant differences between the groups with regard to the frequency of different biotypes, serotypes, and phage types could be demonstrated neither in propionibacteria nor in coagulase-negative staphylococci. The results of typing, however, showed that patients with SE displayed much more frequently several different propionibacterial species and types as well as different micrococcal species and types than persons with healthy skin.