Infection of a total hip arthroplasty with actinomyces israelii: Report of a case

CONTEXT: Infection of following total hip arthroplasties can be classified based on the timing of infection. Late infections with Actinomyces israelii are extremely rare with only 3 previously reported cases in literature. We present another case of a late infection with Actinomyces israelii in a total hip arthroplasty 9 years following implantation. CASE REPORT: A 71-year-old male with diabetes mellitus presented with right hip pain 9 years following a total hip arthroplasty. Physical examination revealed localised pain and biochemical investigations showed elevated inflammatory markers. X-rays were suspicious for infection and a collection around the prosthesis was confirmed by MRI scan. The patient underwent debridement and removal of prosthesis. Peri-operative specimen cultures isolated Actinomyces israelii. The patient responded to a combination of vancomycin followed by ciprofloxacin and linezolid therapy before undergoing a successful second-stage reimplantation surgery. CONCLUSION: This is the first reported case of late haematogenous infection by Actinomyces israelii in a total hip arthroplasty in a patient with diabetes mellitus as the only risk factor. The patient was successfully treated with antibiotic therapy and two-stage reimplantation arthroplasty.