[Pseudallescheria boydii osteoarthritis in a patient with acute lymphoblastic leukemia: a case report]

Case of femoral pseudarthrosis due to Scedosporium apiospermum in an immunocompetent patient with successful conservative treatment and review of literature

Scedosporium apiospermum is a ubiquitous filamentous fungus, commonly found in soil, sewage and polluted waters. It is rarely pathogenic but can cause a broad spectrum of clinical diseases, which can be localised or disseminate to distant organs. The disseminated form of the disease is mostly seen among immunocompromised patients. However, some rare cases of disseminated disease have been reported in immunocompetent individuals. Treatment of these infections is challenging because of their natural resistance to many antifungal agents. Here, we report the case of a 57-year-old immunocompetent patient diagnosed with femoral pseudarthrosis due to S. apiospermum, despite having no obvious clinical sign of infection. Previously, the patient had undergone four iterative femoral surgeries following a road traffic accident which occurred 20 years before. During its last surgery for pseudarthrosis, no clinical or biological signs of infection were present. Per operative samples tested positive for S. apiospermum. The patient was successfully treated with oral voriconazole during 6 months with an excellent tolerance. We also provide a review of literature on bone and joint infections due to Scedosporium spp. (S. apiospermum, Scedosporium boydii and Scedosporium aurantiacum), discussing the evolution of their management and outcome which seems to improve since the use of voriconazole.

Septic arthritis in immunocompetent and immunosuppressed hosts

Septic arthritis has long been considered an orthopedic emergency. Historically, Neisseria gonorrhoeae and Staphylococcus aureus have been the most common causes of septic arthritis worldwide but in the modern era of biological therapy and extensive use of prosthetic joint replacements, the spectrum of microbiological causes of septic arthritis has widened considerably. There are also new approaches to diagnosis but therapy remains a challenge, with a need for careful consideration of a combined medical and surgical approach in most cases.

ScedosporiumSpecies Infections and Treatments

Scedosporium species are now increasingly isolated from immunocompromised and immunocompetent patients. Unfortunately, Scedosporium species infections are generally resistant to amphotericin B, and S. prolificans strains are particularly resistant to presently-available antifungal agents. Here we review the microbiology, expanding epidemiology, numerous clinical presentations, and diagnostic tools available for Scedosporium species infections. Finally, we detail the available in vitro, animal model, and clinical data on the treatment of Scedosporium species infections with special emphasis on the role of newer antifungal therapies for these recalcitrant infections.

Pseudallescheria boydii infection of a prosthetic hip joint--an uncommon infection in a rare location

Pseudallescheria boydii infection of the hip joint was diagnosed 2.5 years after implantation of a prosthetic joint in a woman with rheumatoid arthritis. Cure was achieved with a 10-month course of voriconazole coupled with removal of the prosthesis and repeat surgical debridement. Pseudallescheria boydii is an environmental mold that can cause osteoarticular infection, most often not only after local trauma but also after local injections and surgical procedures. Hip involvement was rarely reported, and this is the first description of a prosthetic joint infection with Scedosporium sp.

Infections caused by Scedosporium spp

Scedosporium spp. are increasingly recognized as causes of resistant life-threatening infections in immunocompromised patients. Scedosporium spp. also cause a wide spectrum of conditions, including mycetoma, saprobic involvement and colonization of the airways, sinopulmonary infections, extrapulmonary localized infections, and disseminated infections. Invasive scedosporium infections are also associated with central nervous infection following near-drowning accidents. The most common sites of infection are the lungs, sinuses, bones, joints, eyes, and brain. Scedosporium apiospermum and Scedosporium prolificans are the two principal medically important species of this genus. Pseudallescheria boydii, the teleomorph of S. apiospermum, is recognized by the presence of cleistothecia. Recent advances in molecular taxonomy have advanced the understanding of the genus Scedosporium and have demonstrated a wider range of species than heretofore recognized. Studies of the pathogenesis of and immune response to Scedosporium spp. underscore the importance of innate host defenses in protection against these organisms. Microbiological diagnosis of Scedosporium spp. currently depends upon culture and morphological characterization. Molecular tools for clinical microbiological detection of Scedosporium spp. are currently investigational. Infections caused by S. apiospermum and P. boydii in patients and animals may respond to antifungal triazoles. By comparison, infections caused by S. prolificans seldom respond to medical therapy alone. Surgery and reversal of immunosuppression may be the only effective therapeutic options for infections caused by S. prolificans.

Scedosporium apiospermum: changing clinical spectrum of a therapy-refractory opportunist*

Current knowledge on the opportunist Scedosporium apiospermum (teleomorph: Pseudallescheria boydii), generated over a period of more than 120 years, is reviewed. The natural environmental habitat of the fungus is unknown; nutrient-rich, brackish waters like river estuaria have been suggested. The fungus is strongly promoted by agricultural and particularly by industrial pollution.

Mycotic osteomyelitis due to Scedosporium Apiospermum: MR imaging-pathologic correlation

Mycotic osteomyelitis is rare and occurs in immunocompromised patients after inoculation of the pathogen at a penetrating trauma site. Mycotic osteomyelitis due to Scedosporium Apiospermum is extremely rare, with only 13 cases of septic arthritis reported previously. Ours is only the third case of S. apiospermum osteomyelitis in an immunocompromised patient and the only patient with a histopathologic diagnosis from an amputation specimen. Recognition of this pathogen may be delayed due to insidious onset and negative joint fluid cultures, often requiring synovial or bone biopsies to establish the diagnosis. Delay in appropriate treatment may result in disseminating infection or even death.

Scedosporium prolificans osteomyelitis in an immunocompetent child treated with voriconazole and caspofungin, as well as locally applied polyhexamethylene biguanide

Scedosporium species are increasingly isolated from immunocompromised and immunocompetent patients. Unfortunately, Scedosporium infections are generally resistant to amphotericin B, and Scedosporium prolificans strains are particularly resistant to the antifungal agents now in use. We report here on an immunocompetent child with S. prolificans-associated osteomyelitis successfully treated with debridement, local irrigation with polyhexamethylene biguanide, and the systemic administration of voriconazole and caspofungin despite poor in vitro activity of voriconazole alone against the isolate. We also review the treatments and outcomes of 28 reported cases of osteomyelitis or septic arthritis caused by Scedosporium species in immunocompetent patients.

Pseudallescheria boydii knee arthritis in a young immunocompetent adult two years after a compound patellar fracture

Pseudallescheria boydii arthritis of the knee developed in a 32-year-old immunocompetent man 2 years after a compound patellar fracture contaminated with soil. No other potential portal of entry was identified, suggesting that the fungus remained latent for 2 years. Pseudallescheria arthritis often occurs after a prolonged latency period, causing minimal symptoms that contrast with the frequently severe radiological changes. Although this organism often shows limited sensitivity to most antifungal agents, our patient achieved a full recovery after surgical synovectomy and 6 months of itraconazole therapy (400 mg/ d). This case illustrates the importance of testing for fungi in patients with torpid arthritis, particularly when mild clinical symptoms contrast with severe bone and joint destruction.