Epidemiology and risk factors for mortality among methicillin-resistant Staphylococcus aureus bacteremic patients in Southern Brazil

Abstract

This study aimed to evaluate the epidemiology and 30-day mortality of adult patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. We retrospectively reviewed the demographic and clinical data of adult patients with S. aureus bloodstream infections (BSI), admitted to a tertiary public teaching medical center in Porto Alegre, Southern Brazil, from January 2014 to December 2019. A total of 928 patients with S. aureus BSI were identified in the study period (68.5 per 100,000 patient-years), and the proportion of MRSA isolates was 22% (19–27%). Thus, 199 patients were included in the analyses. The median age was 62 (IQR: 51–74) years, Charlson Comorbidity Index (CCI) median was 5 (IQR: 3–6), the Pitt bacteremia score (PBS) median was 1 (IQR: 1–4), and the most common site of infection was skin and soft tissue (26%). Most infections were hospital-acquired (54%), empirical anti-MRSA treatment was initiated in 34% of the cases, and in 44% vancomycin minimum inhibitory concentration was 1.5mg/L or above. Sixty-two (31.2%) patients died up to 30 days after the bacteremia episode. Patients with more comorbid conditions (higher CCI; aOR 1.222, p = 0.006) and a more severe presentation (higher PBS; aOR 1.726, p<0.001) were independently associated with mortality. Empiric antimicrobial therapy with an anti-MRSA regimen was associated with reduced mortality (aOR 0.319, p = 0.016). Our study identified significant risk factors for 30-day mortality in patients with MRSA BSI in a population with a high incidence of S. aureus bacteremia. Empiric treatment with an anti-MRSA drug was a protective factor. No significant variation in the incidence of S. aureus BSI was recorded throughout the period.

Biofilm Producing Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in Humans: Clinical Implications and Management

“…MRSA infections are a significant concern in intensive care units, where many strains have developed resistance to various antibiotics. These infections are particularly troubling due to their association with hospital settings and the substantial morbidity and mortality they cause [4,6,34]. Adding to the complexity, the adoption of a biofilm state by MRSA where it is encased within a self-produced extracellular matrix allows it to adhere to a wide range of surfaces.…”

“…A significant majority (approximately 90%) of S. aureus infections fall under the category of skin and skin structure infections (SSSI), making up the primary portion of staphylococcal disease [3]. However, infections affecting the bloodstream, respiratory tract, bones, joints, surgical wounds, and increasingly medical devices provoke heightened concern due to their higher rates of illness and death, necessitating prolonged treatment periods [4][5][6]34,42,43]. More recently, severe forms of community-associated infections, including fulminant sepsis, the Waterhouse-Friderichsen syndrome, and necrotizing pneumonia, have emerged as prominent issues.…”