A Rare Case of Periprosthetic Joint Infection with Streptococcus dysgalactiae subspecies dysgalactiae

Area of Science:

• Infectious Diseases
• Microbiology
• Orthopedic Surgery

Background:

• Periprosthetic joint infection (PJI) is a serious complication following joint arthroplasty, often necessitating revision surgery.
• Accurate diagnosis of PJI relies heavily on synovial fluid analysis and microbiological investigations.
• Streptococcus dysgalactiae subspecies equisimilis (SDSE) is a more common cause of PJI than Streptococcus dysgalactiae subspecies dysgalactiae (SDSD).

Observation:

• This report presents the second documented case of PJI of the knee caused by SDSD in the medical literature.
• The affected patient was a farmer with comorbidities, working with cattle and sheep, suggesting a potential zoonotic origin.
• The causative agent, SDSD, is more typically associated with animal infections.

Findings:

• The patient underwent surgical treatment including excisional debridement, open washing, decompression, and liner exchange.
• Bacterial identification was confirmed as SDSD using the VITEK MS system.
• The patient demonstrated a full recovery with no recurrence of infection after a 1-year follow-up period.

Implications:

• This case highlights the importance of considering less common bacterial species, such as SDSD, in the differential diagnosis of PJI, especially in individuals with relevant occupational or environmental exposures.
• It underscores the potential for zoonotic transmission of certain bacterial pathogens to humans, leading to severe orthopedic infections.
• Successful management of this rare PJI case through surgical intervention and appropriate treatment provides valuable insights for clinicians managing similar complex infections.