Avoidable antibiotic exposure for uncomplicated skin and soft tissue infections in the ambulatory care setting

Abstract

Background: Uncomplicated skin and soft tissue infections are among the most frequent indications for outpatient antibiotics. A detailed understanding of current prescribing practices is necessary to optimize antibiotic use for these conditions.

Methods: This was a retrospective cohort study of children and adults treated in the ambulatory care setting for uncomplicated cellulitis, wound infection, or cutaneous abscess between March 1, 2010 and February 28, 2011. We assessed the frequency of avoidable antibiotic exposure, defined as the use of antibiotics with broad gram-negative activity, combination antibiotic therapy, or treatment for 10 or more days. Total antibiotic-days prescribed for the cohort were compared with antibiotic-days in 4 hypothetical short-course (5-7 days), single-antibiotic treatment models consistent with national guidelines.

Results: A total of 364 cases were included for analysis (155 cellulitis, 41 wound infection, and 168 abscess). Antibiotics active against methicillin-resistant Staphylococcus aureus were prescribed in 61% of cases of cellulitis. Of 139 cases of abscess where drainage was performed, antibiotics were prescribed in 80% for a median of 10 (interquartile range, 7-10) days. Of 292 total cases where complete prescribing data were available, avoidable antibiotic exposure occurred in 46%. This included use of antibiotics with broad gram-negative activity in 4%, combination therapy in 12%, and treatment for 10 or more days in 42%. Use of the short-course, single-antibiotic treatment strategies would have reduced prescribed antibiotic-days by 19% to 55%.

Conclusions: Approximately half of uncomplicated skin infections involved avoidable antibiotic exposure. Antibiotic use could be reduced through treatment approaches using short courses of a single antibiotic.

Keywords: Abscess; Antimicrobial stewardship; Cellulitis; Skin and soft tissue infection; Uncomplicated skin and soft tissue infection.

Figure 1

Study schematic

Figure 2

Estimated total antibiotic-days prescribed in the study cohort and in four hypothetical short-course, single-antibiotic treatment models. Treatment strategy 1: 7-day course of a single antibiotic for all cases. Treatment strategy 2: no antibiotic therapy for cases of abscess meeting IDSA criteria for drainage alone, 7-day course of a single antibiotic for all other cases. Treatment strategy 3: 5-day course of a single antibiotic for all cases. Treatment strategy 4: no antibiotic therapy for cases of abscess meeting IDSA criteria for drainage alone, 5-day course of a single antibiotic for all other cases. Dashed boxes indicate the relative reduction in total antibiotic-days that would be achieved utilizing each respective treatment strategy compared with the study cohort.