A prospective observational cohort study in primary care practices to identify factors associated with treatment failure in Staphylococcus aureus skin and soft tissue infections.

Grace C Lee,Christopher R Frei,Lucina B Treviño,Randall J Olsen,Kenneth A Lawson,James Wilson,Natalie K Boyd,Liem C Du,Chad Retzloff,Ronald G Hall,Sylvia B Treviño,Steven D Dallas,Yufeng Wang

doi:10.1186/s12941-016-0175-8

Abstract

BackgroundThe incidence of outpatient visits for skin and soft tissue infections (SSTIs) has substantially increased over the last decade. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has made the management of S. aureus SSTIs complex and challenging. The objective of this study was to identify risk factors contributing to treatment failures associated with community-associated S. aureus skin and soft tissue infections SSTIs.MethodsThis was a prospective, observational study among 14 primary care clinics within the South Texas Ambulatory Research Network. The primary outcome was treatment failure within 90 days of the initial visit. Univariate associations between the explanatory variables and treatment failure were examined. A generalized linear mixed-effect model was developed to identify independent risk factors associated with treatment failure.ResultsOverall, 21% (22/106) patients with S. aureus SSTIs experienced treatment failure. The occurrence of treatment failure was similar among patients with methicillin-resistant S. aureus and those with methicillin-susceptible S. aureus SSTIs (19 vs. 24%; p = 0.70). Independent predictors of treatment failure among cases with S. aureus SSTIs was a duration of infection of ≥7 days prior to initial visit [aOR, 6.02 (95% CI 1.74–19.61)] and a lesion diameter size ≥5 cm [5.25 (1.58–17.20)].ConclusionsPredictors for treatment failure included a duration of infection for ≥7 days prior to the initial visit and a wound diameter of ≥5 cm. A heightened awareness of these risk factors could help direct targeted interventions in high-risk populations.

Highlights

The incidence of outpatient visits for skin and soft tissue infections (SSTIs) has substantially increased over the last decade
Factors associated with treatment failure included Black race, weight ≥110 kg, Multidrug resistance (MDR), duration of skin infection prior to visit ≥7 days, lesion diameter ≥5 cm, lesion size ≥25 cm2, and abscess formation (Table 1)
Independent predictors of treatment failure among cases with S. aureus SSTIs were duration of skin infection prior to visit ≥7 days [adjusted odd ratio (aOR), 6.02], and a lesion diameter size ≥5 cm [aOR, 5.25]

Summary

Introduction

The incidence of outpatient visits for skin and soft tissue infections (SSTIs) has substantially increased over the last decade. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has made the management of S. aureus SSTIs complex and challenging. The objective of this study was to identify risk factors contributing to treatment failures associated with community-associated S. aureus skin and soft tissue infections SSTIs. The incidence of outpatient and emergency department visits for skin and soft tissue infections (SSTIs) has substantially increased with the emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) [1]. Two studies set in urgent care and primary care clinics found 35% of patients with CA-MRSA SSTIs experienced treatment failure and 78% reported SSTI recurrence [5, 6]. SSTIs due to CA-MRSA have been implicated to have more serious outcomes compared to community-associated methicillin susceptible S. aureus (CA-MSSA) SSTIs; there are limited studies evaluating the differences in treatment outcomes in the primary care setting. Tools to better identify those who are at higher risk of experiencing treatment failure are needed to better inform treatment decisions in the outpatient setting

Objectives

Methods

Results

Discussion

Conclusion