Treatment failure definitions for non-purulent skin and soft tissue infections: a systematic review

Objective There is currently no uniform definition for antimicrobial treatment failure for adults with non-purulent skin and soft tissue infections (SSTIs). The objective of this systematic review was to identify treatment failure definitions and their common components in the literature. Methods Five electronic databases were searched from inception to March 2019. Two independent reviewers identified studies involving adults (age >= 18 years) with non-purulent SSTIs in which antimicrobial treatment failure was a defined outcome. There were no language restrictions. Only randomized trials or observational studies were included. Results After screening 4953 abstracts, 26 studies (N = 6629 patients) met full inclusion criteria. Reported treatment failure ranged from 0 to 29.5%. The most common definition components were hospital admission (78.9%), change in antibiotics (65.4%), and persistent or worsening signs and symptoms of infection (34.6%). Only one study listed specific criteria for persistent or worsening signs and symptoms of infection. Conclusions For studies involving non-purulent SSTIs, the outcome of treatment failure is inconsistently defined and reported failure rates are highly variable. This systematic review has highlighted the need for more robust treatment failure definitions for non-purulent SSTIs. Research should focus on the development of a uniform treatment failure definition that should be used in future studies.