Characteristics of Staphylococcus aureus isolates from atopic dermatitis with reference to proteolytic activity.

Staphylococcus aureus strains from atopic dermatitis (AD) patients were investigated. Diversities of biological properties, strain relationships and/or group tendencies between strains were analysed. Fifty four S. aureus strains were divided into seven biotypes using a standard biochemical API Staph system. The largest population (twenty two isolates, 40.7%) belonged to biotype A No. 6716153. Using a standard phage set S. aureus isolates were typed into three groups: I, II and III. However, twenty seven (50.0%) isolates belonged to group No. III. Production of proteolytic enzymes was expressed by all isolates, and 87.0% showed high or moderate proteolytic activity. Also alpha or beta haemolysins production by 83.0% of the strains was demonstrated. Antimicrobial susceptibility for each strain was analysed using fifteen antibiotics. Most isolates were sensitive to chloramphenicol (98.0%), neomycin (98.0%) and fucidin (88.0%) and were resistant to ampicillin, oxacillin and rondomycin (< 20.0%). No isolate was sensitive to all antibiotics of our study. Obvious correlations were not observed between biochemical types, phage types, haeomolysin production and antibiotic resistance pattern but proteolytic activity was demonstrated by most strains in each test.