[A man with pain following a knee operation]

Area of Science:

• Orthopedic Surgery
• Infectious Diseases
• Microbiology

Background:

• Post-arthroscopy infections are rare but serious complications.
• Atypical microbiological agents can complicate diagnosis and treatment.
• Early recognition and appropriate management are crucial for favorable outcomes.

Observation:

• A previously healthy man developed severe knee pain, swelling, and fever eight days after arthroscopic surgery.
• Re-arthroscopy revealed joint bleeding but no initial signs of infection.
• Joint fluid analysis identified Staphylococcus lugdunensis as the causative agent.

Findings:

• Staphylococcus lugdunensis, a coagulase-negative staphylococcus, demonstrated high virulence.
• The patient received a combination antibiotic therapy including cloxacillin, gentamicin, and linezolid.
• Aggressive treatment led to a full recovery without long-term complications.

Implications:

• Staphylococcus lugdunensis should be considered a potential pathogen in post-arthroscopic infections.
• Microbiological identification is critical, and S. lugdunensis should not be dismissed as a contaminant.
• This case underscores the importance of prompt and effective antibiotic treatment for severe joint infections.