Methicillin-sensitive Staphylococcus aureus lineages contribute towards poor patient outcomes in orthopaedic...

Area of Science:

• Infectious Diseases
• Genomics
• Clinical Microbiology

Background:

• Staphylococci, particularly Staphylococcus aureus, are primary causes of orthopaedic device-related infections (ODRIs).
• Understanding the genetic and phenotypic factors influencing ODRI treatment outcomes is crucial for improving patient care.

Purpose of the Study:

• To investigate the association between genomic and phenotypic variations of Staphylococcus aureus isolates and clinical outcomes in patients with ODRIs.
• To identify genetic factors potentially linked to infection severity and treatment success in ODRI cases.

Main Methods:

• Prospective collection of 86 invasive S. aureus isolates from ODRI patients.
• Whole-genome sequencing and molecular characterization of isolates.
• Clinical outcome assessment at a 24-month follow-up, classifying patients as 'cured' or 'not cured'.

Main Results:

• Most isolates were methicillin-susceptible S. aureus (MSSA; 94%) and carried virulence genes, including toxin and biofilm-associated genes.
• Genomic analysis identified globally circulating community- and hospital-acquired lineages.
• Genetic variations were identified that may correlate with infection severity or clinical outcomes.

Conclusions:

• While antibiotic resistance (e.g., MRSA) contributes to treatment failure, methicillin-susceptible S. aureus (MSSA) can also cause severe infections with poor outcomes.
• Genetic variance in S. aureus isolates warrants further investigation for its role in ODRI pathogenesis and treatment response.
• Host immune response plays a role, but specific bacterial genetic factors may also influence ODRI outcomes.