Late onset prosthetic joint infection caused by Parvimonas micra

Area of Science:

• Microbiology
• Infectious Diseases
• Orthopedic Surgery

Background:

• Parvimonas micra is a gram-positive anaerobic bacterium, part of the human microbiota, primarily found in the oral cavity.
• Prosthetic joint infections (PJIs) are serious complications, and P. micra is an uncommon causative agent.
• Late-onset PJIs can be challenging to diagnose and treat, especially with rare pathogens.

Observation:

• An 87-year-old woman presented with a late-onset knee prosthetic joint infection.
• The infection was caused by Parvimonas micra, a microorganism rarely implicated in PJIs.
• The patient had a history of prosthetic knee surgery.

Findings:

• The patient was treated with a two-step surgical protocol involving prosthetic material removal and antibiotic-loaded cement spacer placement.
• Intravenous antimicrobial therapy was administered for two weeks, followed by six weeks of oral therapy.
• Successful eradication of the P. micra infection was achieved.

Implications:

• This case expands the understanding of Parvimonas micra as a pathogen in prosthetic joint infections.
• It underscores the importance of considering rare microorganisms in the differential diagnosis of late-onset PJIs.
• The successful management highlights the efficacy of a combined surgical and antibiotic approach for P. micra PJIs.