Staphylococcus aureus native arthritis over 10 years

Area of Science:

• Infectious Diseases
• Microbiology
• Clinical Medicine

Background:

• Septic arthritis, particularly from Staphylococcus aureus, leads to severe morbidity and mortality.
• Staphylococcus aureus is a leading cause of native joint infectious arthritis.

Purpose of the Study:

• To analyze the microbiological features of Staphylococcus aureus causing native arthritis.
• To investigate the impact of these features on clinical outcomes.

Main Methods:

• Retrospective study of S. aureus native arthritis cases (2005-2015).
• Phenotypic analysis included antimicrobial susceptibility, hemolysis, agr functionality, and biofilm formation.
• Genotypic analysis involved pulsed-field gel electrophoresis and DNA microarrays.
• Primary endpoint was microbiological treatment failure (relapse, persistence, or death).

Main Results:

• Seven of 29 patients had methicillin-resistant S. aureus (MRSA) arthritis; 19 had methicillin-susceptible S. aureus (MSSA) arthritis.
• Treatment failure was higher in MRSA infections (57.1%) compared to MSSA (15.8%).
• Case fatality was significantly higher in MRSA infections (3/7) versus MSSA (0/19).
• Clonal complex 5 (CC5) was most frequent (38.1%).
• MSSA strains showed greater genetic variability than MRSA strains.

Conclusions:

• Methicillin resistance is a key factor in poor outcomes for S. aureus septic arthritis.
• No other phenotypic or genotypic factors were associated with adverse outcomes.
• CC5 was the predominant clonal complex, with MSSA strains displaying higher genetic diversity.