Epidemiology of Community-Onset Staphylococcus aureus Bacteremia

Introduction: Staphylococcus aureus bacteremia (SAB) is the second-most common cause of community-onset (CO) bacteremia. The incidence of methicillin-resistant S. aureus (MRSA) has recently decreased across much of the United States, and we seek to describe risk factors for COMRSA bacteremia, which will aid emergency providers in their choice of empiric antibiotics.Methods: This is a retrospective cohort study of all patients with SAB at a 500-bed safety net hospital. The proportion of S. aureus isolates that were MRSA ranged from 32-35% during the study period. Variables of interest included age, comorbid medical conditions, microbiology results, antibioticadministration, duration of bacteremia, duration of hospital admission, suspected source of SAB, and Elixhauser comorbidity score. The primary outcome was to determine risk factors for CO-MRSA bacteremia as compared to methicillin-susceptible S. aureus (MSSA) bacteremia in patients admittedto the hospital through the emergency department.Results: We identified 135 consecutive patients with CO-SAB. In comparison to those with MSSA bacteremia, patients with MRSA bacteremia were younger (odds ratio [OR] 0.5, 95% confidence interval [CI], 0.4-0.7) with higher Elixhauser comorbidity scores (OR 1.4, 95% CI, 1.1-1.7). Additionally, these patients were more likely to have a history of MRSA infection or colonization (OR 8.9, 95% CI,2.7-29.7) and intravenous drug use (OR 2.4, 95% CI, 1.0-5.7).Conclusion: SAB continues to be prevalent in our urban community with CO-MRSA accounting for almost one-third of SAB cases. Previous MRSA colonization was the strongest risk factor for current MRSA infection in this cohort of patients with CO-SAB

Epidemiology of Community-Onset Staphylococcus aureus Bacteremia

Introduction: Staphylococcus aureus bacteremia (SAB) is the second-most common cause of community-onset (CO) bacteremia. The incidence of methicillin-resistant S. aureus (MRSA) has recently decreased across much of the United States, and we seek to describe risk factors for CO-MRSA bacteremia, which will aid emergency providers in their choice of empiric antibiotics. Methods: This is a retrospective cohort study of all patients with SAB at a 500-bed safety net hospital. The proportion of S. aureus isolates that were MRSA ranged from 32–35% during the study period. Variables of interest included age, comorbid medical conditions, microbiology results, antibiotic administration, duration of bacteremia, duration of hospital admission, suspected source of SAB, and Elixhauser comorbidity score. The primary outcome was to determine risk factors for CO-MRSA bacteremia as compared to methicillin-susceptible S. aureus (MSSA) bacteremia in patients admitted to the hospital through the emergency department. Results: We identified 135 consecutive patients with CO-SAB. In comparison to those with MSSA bacteremia, patients with MRSA bacteremia were younger (odds ratio [OR] 0.5, 95% confidence interval [CI], 0.4–0.7) with higher Elixhauser comorbidity scores (OR 1.4, 95% CI, 1.1–1.7). Additionally, these patients were more likely to have a history of MRSA infection or colonization (OR 8.9, 95% CI, 2.7–29.7) and intravenous drug use (OR 2.4, 95% CI, 1.0–5.7). Conclusion: SAB continues to be prevalent in our urban community with CO-MRSA accounting for almost one-third of SAB cases. Previous MRSA colonization was the strongest risk factor for current MRSA infection in this cohort of patients with CO-SAB

Clinical characteristics, diagnostic evaluation, and antibiotic prescribing patterns for skin infections in nursing homes

Background: The epidemiology and management of skin infections in nursing homes has not been adequately described. We reviewed the characteristics, diagnosis and treatment of skin infections among residents of nursing homes to identify opportunities to improve antibiotic use. Methods: A retrospective study involving 12 nursing homes in the Denver metropolitan area. For residents at participating nursing homes diagnosed with a skin infection between July 1, 2013 and June 30, 2014, clinical and demographic information was collected through manual chart review.Results: Of 100 cases included in the study, the most common infections were non-purulent cellulitis (n=55), wound infection (n=27), infected ulcer (n=8), and cutaneous abscess (n=7). In 26 cases, previously published minimum clinical criteria for initiating antibiotics (Loeb criteria) were not met. Most antibiotics (n=52) were initiated as a telephone order following a call from a nurse, and 41 patients were not evaluated by a provider within 48 hours after initiation of antibiotics. Nearly all patients (n=95) were treated with oral antibiotics alone. The median treatment duration was 7 days (interquartile range [IQR] 7-10); 43 patients received treatment courses of ≥ 10 days.Conclusions: Most newly diagnosed skin infections in nursing homes were non-purulent infections treated with oral antibiotics. Antibiotics were initiated by telephone in over half of cases, and lack of a clinical evaluation within 48 hours after starting antibiotics was common. Improved diagnosis through more timely clinical evaluations and decreasing length of therapy are important opportunities for antibiotic stewardship in nursing homes