Prosthetic joint infection after total hip arthroplasty caused by Sneathia sanguinegens: A case report (CARE-complaint)

Abstract

Introduction: Sneathia sanguinegens(S sanguinegens) is a gram-negative rod-shaped bacterium mostly reported to cause a perinatal infection, and there are no reports of S sanguinegens in prosthetic joint infection (PJI). The purpose of this report is to describe a very rare case of PJI after total hip arthroplasty (THA) caused by S sanguinegens.

Patient concerns: A 79-year-old woman presented with right coxalgia, inability to walk, and a fever of 39°C. She had undergone THA 28 years earlier for osteoarthritis of the hip.

Diagnoses: The diagnosis was acute late-onset PJI, because blood tests revealed marked inflammatory reaction and computed tomography showed an abscess at the right hip joint; synovial fluid analysis resulted in detection of a gram-negative bacillus.

Intervention: Surgical debridement with retention of the implant and antibiotic therapy was performed.

Outcomes: One month after surgery, polymerase chain reaction (PCR) assay showed that the pathogen was 99.9% likely to be S sanguinegens. There has been no recurrence of infection or loosening of the implant in the 2 years since her surgery.

Lessons: PCR should facilitate detection of previously unknown pathogens and potentially novel bacterial species.

Figure 1

Radiological images. Plain radiograph of the right hip at the time of admission showing slight osteolytic changes at around the implant (black arrow), but no evidence of loosening of the implant.

Figure 2

Radiological images. Contrast-enhanced computed tomography scan showing a ring-enhancing region around the right hip joint suggesting abscess formation (black arrow).

Figure 3

Photograph of Gram staining of synovial fluid of hip joint. Analysis reveals a gram-negative bacillus (black arrow). Scale bar, 10 μm.

Figure 4

Plain radiograph immediately after surgery. The implant is retained, the wire and screw were removed.

Figure 5

Timeline. Historical and current information from this episode of care.