Candida albicans Sacral Osteomyelitis Causing Necrosis of a Sacral Nerve Root: A Case Report

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.

Isolated cryptococcal osteomyelitis of the sacrum in an immunocompetent patient: a case report and literature review

BACKGROUND

Cryptococcus neoformans, an opportunistic fungal pathogen, seldom causes infection in immunocompetent people. Cryptococcal osteomyelitis is an uncommon condition in which Cryptococcus invades the bone. It usually occurs as part of a disseminated infection and rarely in isolation. The spine has been reported as the most common site of cryptococcal osteomyelitis; however, isolated case of sacrum involvement in immunocompetent patients has never been reported.

CASE PRESENTATION

We report the case of a 37-year-old man without underlying disease who presented with progressive low back and sacrococcygeal pain. The patient was initially diagnosed with sacral tumour by a local doctor, and subsequently, after admission, was diagnosed with sacral tuberculosis. He was empirically treated with antitubercular drugs. The patient failed to respond to antitubercular drugs and complained of worsening low back pain. Additionally, he developed persistent radiating pain and numbness in his legs. For further diagnosis, we performed a computed tomography-guided puncture biopsy of the sacrum, which revealed granulomatous inflammation with massive macrophage infiltration and special staining revealed a fungal infection. We performed sacral debridement and drainage and obtained purulent specimens for pathological examination and microbial culture. Microbial identification and drug susceptibility tests revealed a Cryptococcus neoformans infection sensitive to fluconazole. Postoperatively, the persistent radiating pain and numbness in the legs resolved. After 12 consecutive weeks of antifungal therapy, all his symptoms resolved. The patient remained without any signs of recurrence at the 8-month follow-up.

CONCLUSION

We reported a rare case of isolated sacrum cryptococcal osteomyelitis in an immunocompetent patient. Furthermore, we identified and reviewed 18 published cases of spine cryptococcal osteomyelitis. Immunocompetent individuals are also at risk for cryptococcal osteomyelitis. Clinical manifestation and imaging are insufficient to diagnose cryptococcal osteomyelitis of the spine, and invasive examinations, such as puncture biopsy and fungal examinations, are needed. Antifungal therapy yields satisfactory results for the treatment of cryptococcal osteomyelitis of the spine, however, if the infective lesion is large, especially when it compresses the spinal cord and nerves, a regimen combining aggressive surgery with antifungal therapy is indispensable.

Vertebral Candidiasis, the State of the Art: A Systematic Literature Review

OBJECTIVE

In recent years, Candida spondylodiscitis has represented an increasingly emerging disease in clinical practice. This condition requires long-term antibiotic therapy and sometimes surgical treatments. The main purpose of this study is to investigate the epidemiology, clinical and radiological aspects, treatment protocols, and outcomes of Candida-mediated vertebral osteomyelitis.

METHODS

A systematic review of the English literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.The research was conducted on Medline, Cochrane library, PubMed, and Scopus using as search terms "vertebral"; "spinal"; "infection"; "spondylodiscitis"; "discitis"; "osteomyelitis"; "Candida"; and "Candidosis." A case of vertebral candidiasis that was surgically managed was also reported.

RESULTS

In total, 88 articles were included in our systematic review. Including the reported case, our analysis covered 113 cases of vertebral candidiasis. Candida albicans was isolated in 64 cases (56.1%), Candida tropicalis in 21 (18.4%), Candida glabrata in 14 (12.3%), and Candida parapsilosis in five (4.4%). The mean duration of the follow-up was 395 days. Finally, 87 (82%) patients completely recovered, ten (9.4%) died, and nine (8.5%) reported sequelae.

CONCLUSION

This systematic review summarized the state of the art on vertebral candidiasis, describing data on its clinical features, diagnostic criteria and current limitations, and treatment alternatives and their outcomes.