Recurrent knee septic arthritis and osteomyelitis due to Candida viswanathii: a case report and literature review.

Background: Candida viswanathii is a rare Candida with fewer than 40 clinical cases of infection reported globally and with limited treatment descriptions available. Here we report a rare case of recurrent candida septic arthritis and osteomyelitis caused by C. viswanathii.

Case presentation: A 78-year-old Chinese female developed her first episode of C. viswanathii septic arthritis and osteomyelitis likely following intra-articular lignocaine injections to her left knee. She was treated with 2 surgical washouts and 16 months of antifungal agents, which included an initial 6 months of voriconazole followed by fluconazole, with full recovery. However, she presents with recurrence of left knee pain 14 months after antifungal therapy was stopped. Open arthrotomy revealed extensive synovitis and granulation tissue, with a sinus tract extending to the anterior patella. C. viswanathii was re-cultured in her synovial fluid and identified via a combination of fungal phenotypic tests and DNA sequencing of the ITS region and the D1/D2 region of the 28 S ribosomal subunit. She was managed with two open knee arthrotomies, drainage with curettage and debridement, and was reinitiated on oral voriconazole therapy, to which she demonstrated a good clinical response. She was subsequently maintained on chronic suppressive oral voriconazole therapy. Her symptoms remain well controlled, and no relapse was observed on the last follow-up. Additionally, we have also done a comprehensive literature review of all the published clinical cases of C. viswanathii thus far.

Conclusion: This is the first case report to describe the successful treatment and monitoring of recurrent C. viswanathii osteoarticular infection. Combined with our literature review, we aim to increase understanding of this rare candida species- specifically its clinical trajectory in osteoarthritic infections, laboratory features, radiological characteristics, intra-operative findings, and treatment aspects inclusive of a potential role for long-term suppressive therapy.