Epidemiology of Fungal Osteomyelitis

Fungal Musculoskeletal Infections: Comprehensive Approach to Proper Diagnosis

Fungal musculoskeletal infections often have subacute or indolent manifestations, making it difficult to distinguish them from other diseases and infections, given that they are relatively uncommon. Fungal infections occur by hematogenous spread, direct inoculation, or contiguous extension and may be related to different risk factors, including immunosuppression and occupational activity. The infection can manifest in isolation in the musculoskeletal system or as part of a systemic process. The fungi may be endemic to certain regions or may be found throughout the world, and this can help to narrow the diagnosis of the etiologic agent. Infections such as candidiasis, cryptococcosis, aspergillosis, and mucormycosis are often related to immunosuppression. On the other hand, histoplasmosis, paracoccidioidomycosis, coccidioidomycosis, and blastomycosis can occur in healthy patients in geographic areas where these infections are endemic. Furthermore, infections can be classified on the basis of the site of infection in the body. Some subcutaneous infections that can have osteoarticular involvement include mycetoma, sporotrichosis, and phaeohyphomycosis. Different fungi affect specific bones and joints with greater prevalence. Imaging has a critical role in the evaluation of these diseases. Imaging findings include nonspecific features such as osteomyelitis and arthritis, with bone destruction, osseous erosion, mixed lytic and sclerotic lesions, and joint space narrowing. Multifocal osteomyelitis and chronic arthritis with joint effusion and synovial thickening may also occur. Although imaging findings are often nonspecific, some fungal infections may show findings that aid in narrowing the differential diagnosis, especially when they are associated with the patient's clinical condition and history, the site of osteoarticular involvement, and the geographic location. ©RSNA, 2024.

Fungal Osteomyelitis of the Hip with Septic Arthritis: Case Report

Fungal osteomyelitis, especially associated with septic arthritis, is uncommon in Brazil; therefore, sometimes it is difficult to diagnose and treat it. We report the case of a young patient, with no immunosuppressive risk factor, with osteomyelitis leading to septic arthritis of the hip. The diagnosis was performed after surgical drainage and visualization of Cryptococcus neoformans at pathological anatomy. Antifungal treatment resulted in complete remission of the symptoms. Since there is no consensus on the treatment of fungal osteomyelitis, this case report aims to inform orthopedists about the importance of hip arthritis differential diagnosis and the good evolution of clinical treatment after drainage and pathogen isolation.

Malassezia restricta as an unexpected cause of infectious osteomyelitis diagnosed by metagenomic sequencing: a case report and literature review

BACKGROUND

Malassezia restricta, a lipophilic and lipodependent yeast belonging to the basidiomycetes group, is an opportunistic fungal pathogen associated with various skin diseases, including seborrheic dermatitis and dandruff. Typically, Malassezia infection in neonates manifests as fungemia or hematogenous dissemination to the bone or lungs. However, vertebral osteomyelitis caused by these fungi is rarely reported owing to non-specific clinical presentations and laboratory/imaging findings. The Pathogen Metagenomics Sequencing (PMseq) technique enables direct high-throughput sequencing of infected specimens, facilitating the rapid and accurate detection of all microorganisms in clinical samples through comprehensive reports.

CASE PRESENTATION

A 52-year-old male was admitted to our hospital on July 20, 2022 with a 3-month history of ambulatory difficulties and localized low back pain. Magnetic Resonance Imaging (MRI) examination of the spinal column revealed irregular bone destruction affecting the L2, L3, and L5 vertebral bodies. Additionally, low T1 and high T2 intensity lesions were observed at the intervertebral discs between L3 and L5. The presumptive diagnosis of tuberculous spondylitis was made based on the imaging findings, despite negative results in all mycobacterium tests. However, the patient exhibited no improvement after receiving regular anti-tuberculosis treatment for 3 months. Subsequent MRI revealed an expansive abnormal signal within the vertebral body, leading to progressive bone destruction. The absence of spinal tuberculosis or other infective microorganisms was confirmed through culture from blood and pathological tissue from the L4 vertebral body. Subsequently, PMseq was performed on the specimens, revealing M. restricta as the predominant pathogen with the highest relative abundance value. The pathological examination revealed the presence of fungal mycelium in the L4 vertebral body, with positive findings on periodic Schiff-methenamine and periodic acid-Schiff staining. The anti-tuberculosis treatment was discontinued, and an antifungal combination of fluconazole and voriconazole was administered. All symptoms were resolved after 7 consecutive months of treatment, and the patient was able to ambulate autonomously. Vertebral lesions were reduced on MRI during the 13-month follow-up.

CONCLUSIONS

M. restricta is not a commonly recognized pathogen associated with infectious vertebral osteomyelitis. However, PMseq can aid in diagnosis, timely treatment, and decision making for some non-specific infectious diseases.

Analysis of epidemiological and clinical aspects in cases of fungal osteomyelitis caused by non-Candida species

Osteomyelitis caused by non-Candida species is rare and often neglected, and current recommendations are based on primarily clinical experience and expert opinion. The objective of this study was to describe a case series of non-Candida fungal osteomyelitis. This retrospective study included 10 patients with non-Candida fungal osteomyelitis. Patients with osteomyelitis and microbiologically confirmed non-Candida species from bone fragment cultures were selected from the institution Infection Control Board database. Fusarium spp. were the most commonly isolated fungus from bone fragment cultures in five patients (50%). The majority did not present immunosuppression. The most common etiology was post-traumatic (n = 7, 70%), particularly open fractures. All patients were treated with antifungals associated with surgery. The antifungals used were itraconazole in five patients (50%), and voriconazole in another five patients (50%), with a median duration of antifungal therapy of four weeks (range: 3-25). There were no observed deaths within 30 days and one year. An antifungal approach combined with surgical treatment demonstrated favorable clinical outcomes, including low mortality rates and effective remission.

Fungal Osteomyelitis: A Systematic Review of Reported Cases

Fungal osteomyelitis is considered a rare disease, and the published literature mainly comprises case reports, case series and narrative reviews. A systematic review was undertaken to provide a practice-based global perspective on this disease, focusing on epidemiology and treatment strategies. We searched MEDLINE, EMBASE and Cochrane Library between the 3rd and 8th of March 2023 using a predefined search string. We included studies with at least one patient with a diagnosis of fungal osteomyelitis published before the 1st of January 2023. We included all study designs except for reviews, and we excluded non-English languages and grey literature. After exclusion, 678 studies, mostly case reports, were included. Descriptive analysis was performed on 1072 patients. The most common aetiological agent was Aspergillus (26.5%), followed by Candida (20.7%) and Mucor (16.8%), and the bones most frequently involved were the vertebrae. We described the characteristics of patients divided by site of infection, and we found that diabetes mellitus, disseminated fungal infection, surgery and local lesion were major risk factors. We also successfully associated duration of treatment with outcome. We provided a general overview of this rare disease, and we highlighted the need for high-quality investigations on the subject.

Sustained Release of Antifungal and Antibacterial Agents from Novel Hybrid Degradable Nanofibers for the Treatment of Polymicrobial Osteomyelitis

This study aimed to develop a drug delivery system with hybrid biodegradable antifungal and antibacterial agents incorporated into poly lactic-co-glycolic acid (PLGA) nanofibers, facilitating an extended release of fluconazole, vancomycin, and ceftazidime to treat polymicrobial osteomyelitis. The nanofibers were assessed using scanning electron microscopy, tensile testing, water contact angle analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The in vitro release of the antimicrobial agents was assessed using an elution method and a high-performance liquid chromatography assay. The in vivo elution pattern of nanofibrous mats was assessed using a rat femoral model. The experimental results demonstrated that the antimicrobial agent-loaded nanofibers released high levels of fluconazole, vancomycin, and ceftazidime for 30 and 56 days in vitro and in vivo, respectively. Histological assays revealed no notable tissue inflammation. Therefore, hybrid biodegradable PLGA nanofibers with a sustainable release of antifungal and antibacterial agents may be employed for the treatment of polymicrobial osteomyelitis.

Candida Albicans Osteomyelitis after Chest Wall Blunt Trauma: A Case Report

Fungal osteomyelitis is a rare disease that can occur in immunocompromised patients. We report a case of a patient with a primary rib osteomyelitis after a blunt trauma of the chest wall. Aggressive surgical debridement along with antifungal therapy was the cornerstone of the disease management in this patient.

Mucor Osteomyelitis of the Distal Radius Necessitating Ulnocarpal Fusion

This is a case report of a 60-year-old female who developed distal radius osteomyelitis secondary to Mucor infection from likely hematogenous spread that was managed with ulnocarpal wrist fusion. Following serial debridement and systemic antifungal therapy, ulnocarpal wrist fusion offered functional limb salvage rather than amputation in this patient with significant operative risk and comorbidities.

Clavicular Osteomyelitis Secondary to Candida Parapsilosis Infection

Candida parapsilosis osteomyelitis is a rare diagnosis. Candidal infection can occur via hematogenous or local spread. A localized swelling around a bony structure should raise clinical suspicion. Diagnosis is made by a combination of imaging modalities and biopsy. Anecdotal case reports have been reported in medical literature and treatment guidelines are very limited. Treatment modality includes a combination of surgical debridement and antifungal therapy.

Management of osteoarticular fungal infections in the setting of immunodeficiency

Introduction: Osteoarticular fungal infections (OAFIs) complicate the clinical course of high-risk patients, including immunosuppressed individuals. Their management, however, despite being intricate, is governed by evidence arising from sub-optimal quality research, such as case series. Guidelines are scarce and when present result in recommendations based on low quality evidence. Furthermore, the differences between the management of immunocompromised and immunocompetent patients are not distinct. This is a narrative review after a literature search in PubMed, up to November 2019.Areas covered: The major fungal groups causing osteomyelitis and/or arthritis are Candida spp., Aspergillus spp., non-Aspergillus filamentous fungi, non-Candida yeasts and endemic dimorphic fungi. Their epidemiology is briefly analyzed with emphasis on immunodeficiency and other risk factors. Management of OAFIs includes appropriate antifungal drug therapy (liposomal amphotericin B, triazoles or echinocandins), local surgery and immunotherapy for primary immunodeficiencies. Cessation of immunosuppressive drugs is also mandated.Expert opinion: Management of OAFIs includes affordable and available options and approaches. However, research on therapeutic practices is urgently required to be further improved, due to the rarity of affected patients. Evolution is expected to translate into novel antifungal drugs, less invasive and precise surgical approaches and targeted enhancement of immunoregulatory pathways in defense of challenging fungal pathogens.

Necrotizing fungal osteomyelitis and fingolimod, 4 years after treatment with fingolimod

Fingolimod has been the first approved oral medication in MS for its relapsing remitting type. It is a non-selective sphingosine1-phosphate (S1P) receptor modulator on lymphocytes. Engagement of this receptor blocks the T cells and B cells migration from the lymph nodes into the inflamed central nervous system (CNS) via bloodstream. In spite of this known immunomodulatory mechanism, there are some reports about serious infection following the initiation of fingolimod therapy like herpes types or infections associated to the immunosuppressed situation (cryptococcal meningitis, primary cutaneous cryptococcosis and visceral leishmaniasis). To the best of our knowledge, in contrary to many reports about opportunistic or serious infections with fingolimod, there has been no report on fungal osteomyelitis associated to fingolimod until now. Here, we aimed to describe a woman who developed necrotizing fungal osteomyelitis four years after starting fingolimod, as a disease modifying drug for MS.

Experimental Candida albicans osteomyelitis: Microbiologic, antigenic, histologic, and 18FDG-PET-CT imaging characteristics in a newly established rabbit model

Candida osteomyelitis is a debilitating disease that is difficult to diagnose and treat. As there are no animal models or prospective studies for this uncommon infection, little is known about the pathogenesis, diagnosis, or treatment. We therefore sought to establish an animal model for the study of the pathophysiology, diagnostic modalities, and therapeutic interventions of Candida osteomyelitis. We developed a modified version of the Norden rabbit model of tibial osteomyelitis, in which the right tibia was inoculated intraoperatively with different inocula of C. albicans or normal saline as control. On days 7, 14, and 21 after inoculation, the animals underwent bone radiography, 18-fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography (PET/CT) scan, and blood sampling for blood cultures, blood counts, erythrocyte sedimentation rate, and Candida mannan antigen serum levels. On day 21, animals were euthanized, and infected tibias harvested for culture and histology. Among eight evaluable animals inoculated with 1 × 106 to 1 × 107 cfu, histology and bone cultures established the presence of Candida osteomyelitis in seven, with a host response of neutrophils, mononuclear cells, multinucleate giant cells, fibrosis, and necrosis. Infected animals demonstrated radiological signs of osteomyelitis with significantly increased tracer uptake in 18FDG-PET/CT scans (P < .01) and elevated serum mannan levels (P < .01). All blood cultures were negative. Indices of inflammation were only slightly increased. In conclusion, we report successful establishment of a new animal model of Candida albicans osteomyelitis that may be applicable to advancing our understanding of the pathophysiology, diagnostic modalities, and treatment of this debilitating infection.

Resorbable Beads Provide Extended Release of Antifungal Medication: In Vitro and In Vivo Analyses

Fungal osteomyelitis has been difficult to treat, with first-line treatments consisting of implant excision, radical debridement, and local release of high-dose antifungal agents. Locally impregnated antifungal beads are another popular treatment option. This study aimed to develop biodegradable antifungal-agent-loaded Poly(d,l-lactide-co-glycolide) (PLGA) beads and evaluate the in vitro/in vivo release patterns of amphotericin B and fluconazole from the beads. Beads of different sizes were formed using a compression-molding method, and their morphology was evaluated via scanning electron microscopy. Intrabead incorporation of antifungal agents was evaluated via Fourier-transform infrared spectroscopy, and in vitro fluconazole liberation curves of PLGA beads were inspected via high-performance liquid chromatography. When we implanted the drug-incorporated beads into the bone cavity of rabbits, we found that a high level of fluconazole (beyond the minimum therapeutic concentration [MTC]) was released for more than 49 d in vivo. Our results indicate that compression-molded PLGA/fluconazole beads have potential applications in treating bone infections.

Fungal Musculoskeletal Infections

Fungi are rare but important causes of osteoarticular infections, and can be caused by a wide array of yeasts and molds. Symptoms are often subacute and mimic those of other more common causes of osteoarticular infection, which can lead to substantial delays in treatment. A high index of suspicion is required to establish the diagnosis. The severity of infection depends on the inherent pathogenicity of the fungi, the immune status of the host, the anatomic location of the infection, and whether the infection involves a foreign body. Treatment often involves a combination of surgical debridement and prolonged antifungal therapy.

Bone and joint infections caused by mucormycetes: A challenging osteoarticular mycosis of the twenty-first century

Osteomyelitis and arthritis caused by mucormycetes are rare diseases that rank among the most challenging complications in orthopedic and trauma surgery. The aim of this work is to review the epidemiological, clinical, diagnostic, and therapeutic aspects of the osteoarticular mucormycosis with particular emphasis on high-risk patients. A systematic review of osteoarticular mucormycosis was performed using PUBMED and EMBASE databases from 1978 to 2014. Among 34 patients with median age 41 (0.5-73 years), 24 (71%) were males. While 12 (35%) were immunocompromised patients, 14 (41%) had prior surgery, and seven (21%) suffered trauma. Other underlying conditions included diabetes mellitus, hematological malignancies, transplantation, and corticosteroid therapy. The median diagnostic delay from onset of symptoms and signs was 60 (10-180) days. The principal mechanism of the infection was direct inoculation (n = 19; 56%), and in immunocompromised patients was usually hematogenous disseminated. The long bones were infected by trauma or surgery, while a wide variety of bones were involved by hematogenous dissemination. Combined surgery and amphotericin B treatment were implemented in 28 (82%) and eight (23%) had an unfavorable outcome. Osteoarticular mucormycosis occurs most frequently after trauma or surgical procedures. These infections are progressively destructive and more virulent in individuals with impaired immune systems. Early diagnosis, timely administration of amphotericin B, control of underlying conditions, and surgical debridement of infected tissue are critical for successful management of osteoarticular mucormycosis.