1345ASO and DNase Titers in Patients with Streptococcal Skin Infections in the Dalbavancin DISCOVER Program

Background Elevated values of anti-Streptolysin O (ASO) and DNase-B antibody titers are known to be consistent with antecedent group A streptococcal infections, especially acute streptococcal pharyngitis, acute rheumatic fever or acute glomerulonephritis, but not much is known about their association with streptococcal skin infections. We evaluated the presence of elevated ASO/DNase-B titers in patients enrolled in 2 global phase 3 clinical trials comparing dalbavancin alone to vancomycin/linezolid for the treatment of patients with acute bacterial skin and skin structure infections (ABSSSI). Methods Cultures obtained at a local laboratory at baseline were sent to a central laboratory for species identification. ASO and DNase-B titers were measured at baseline and Day 28. ASO titers were considered elevated if there was a 4 fold increase from baseline or if the titer was >200 kIU/L at any time. Results 52/107 (48.6%) of patients with a positive DNase and elevated ASO titer had a positive streptococcal culture compared to 91/499 (18.2%) of those with a negative titers (p<0.001).