High rates of community-genotype MRSA causing complicated skin and musculoskeletal infections with poor outcomes

The incidence of skin, soft tissue, and musculoskeletal infections (cSSTMIs) has been rising steadily, along with the proportion of cases resulting in therapeutic failure and severe conditions requiring hospitalization. Evidence suggests that inappropriate initial antibiotic therapy is administered in approximately 20–25% of patients, which may contribute to increased morbidity and mortality, higher hospitalization rates, elevated healthcare costs, and a negative impact on patients’ quality of life. The types of lesions and clinical spectra of cSSTMIs range from simple, localized presentations such as small abscesses to life-threatening conditions like deep tissue and necrotizing infections, each with its own unique microbiological profile. Nonetheless, Staphylococcus aureus (S. aureus) remains the principal microorganism associated with these infections
Therefore, clinical-epidemiological studies and molecular analyses of MRSA isolates in community-onset cSSTMIs remain essential to establish clonal relationships among S. aureus strains worldwide, identify risk factors for these infections, and understand factors associated with poorer prognoses.
To evaluate the frequency and the phenotypic and genotypic risk factors associated with severity and death in community-onset complicated skin, soft tissue, and musculoskeletal infections (cSSTMIs) caused by methicillin-resistant Staphylococcus aureus (MRSA).
Patients with community-onset cSSTMIs were assessed between June 2022 and January 2024 and followed for one month after hospital discharge. Tissue samples were obtained through biopsy, punch, or aspiration. All MRSA isolates underwent genomic sequencing. Factors associated with poor outcomes were analyzed using multivariate regression.
A total of 118 patients were included, 60.2% male, with a mean age of 41.1 years (±SD 26.1). Surgical procedures were performed in 21.1%, while recurrence and death occurred in 13.5% and 7.6% of cases, respectively. Among 145 microorganisms isolated, 61.4% were S. aureus, with 24.1% being MRSA and 25.5% multidrug-resistant. Thirty-five MRSA isolates belonged to clonal complexes 5, 8, and 30, with a predominance of the ST105-MRSA-II-t2 clone. Deep tissue involvement showed a statistically significant association with severity (p < 0.001), whereas MRSA genomic characteristics were not correlated with outcomes.
High rates of antimicrobial resistance and elevated MRSA frequency were observed in community-onset cSSTMIs, suggesting the need for empirical coverage against this pathogen, particularly in deep infections, which were significantly associated with severe outcomes.