Secondary infections with beta-hemolytic streptococci in skin lesions.

Secondary infections (SI) in skin lesions are common. In the present study 40 beta-hemolytic streptococci were isolated from 36 patients suffering from SI due to various skin diseases. Staphylococcus aureus coexisted with beta-hemolytic streptococci in 29 of these cases (81%), and beta-hemolytic streptococci were often associated with coagulase-negative staphylococci and gram-positive rods. Eighteen patients (50%) carried beta-hemolytic streptococci predominantly. In most cases of SI due to atopic dermatitis (AD), the predominant species was S. aureus, while in other skin diseases, S. aureus and beta-haemolytica streptococci were predominant in approximately 50% of the patients, except for SI due to tumors and viral diseases. The mean age of patients with SI and beta-hemolytic streptococci was 37 years and that of patients with SI and predominant S. aureus was 32 years. The lower mean age found for S. aureus was due to SI found in patients with AD. This study emphasizes the polymicrobial microbiology of SI.