Treatment of complicated skin and skin structure infections in areas with low incidence of antibiotic resistance-a retrospective population based study from Finland and Sweden.

Complicated skin and skin-structure infections (cSSSI) are a common reason for hospitalization and practically all new antimicrobial agents against Gram-positive bacteria are studied in cSSSI. The aim of this population-based observational study was to assess the treatment of patients with cSSSI in areas with a low incidence of antibiotic resistance. The study population consisted of adult residents who were treated because of cSSSI during 2008-2011 from two Nordic cities, Helsinki and Gothenburg. In the final analysis population (460 patients; mean age 60.8 years; 60.9% male) 13.3% of patients had bacteraemia, 15.9% were admitted to an Intensive Care Unit and 51.5% underwent at least one surgical intervention. Treatment failure occurred in 28.2%, initial antibiotic treatment modification to another intravenous drug in 38.5% and streamlining in 5.0% of the cases. Gram-positive bacteria were predominantly isolated, with staphylococci (24.5%) and streptococci (16.0%) being the most common aetiologies. Median overall durations of hospital stay and antimicrobial treatment were 13 and 17 days, respectively, and on average 3.5 (SD 2.1) different antibiotics were used per patient. Oral antimicrobial treatment was continued in 64.3% of patients after discharge. The overall mortality rates in 30 days and in 12 months were 4.1% and 11.8%, respectively, and 16.4% of patients had a recurrence of SSSI within 12 months. In conclusion, in this population-based study antimicrobial treatment modifications were frequent and the treatment time was longer than recommended. However, bacteraemia, clinical failure and recurrences were more common than in previous non-population-based studies.