Unusual fungal infection of the spine: A case report of Acremonium-induced vertebral osteomyelitis

• Rare case of fungal osteomyelitis by Acremonium spp in immunocompetent patient. • Diagnosis delayed due to overlapping clinical symptoms with other spinal conditions. • MRI and fungal culture key in timely detection of Acremonium vertebral infection. • Voriconazole treatment for Acremonium osteomyelitis with good safety profile. • Surgical and antifungal combination therapy may improve outcomes. Fungal vertebral osteomyelitis (VO) is a rare disease, typically caused by Aspergillus or Candida spp. Acremonium spp., especially in the spine, is uncommon. While classically affecting immuno-compromised patients, cases in immuno-competent hosts are increasingly reported. Diagnosis relies on beta D-glucan, MRI and galactomannan assays, with voriconazole as preferred therapy. We report a rare case of fungal osteomyelitis in a 33-year-old immunocompetent adult male, with complaints of gradually progressing back pain accompanied by pain in the right leg for three months. Over the past year, this patient underwent L5-S1 laminectomy for disc radiculopathy after failed conservative treatment to resolve symptoms of left leg numbness. Magnetic Resonance Imaging showed discitis at surgical site without an abscess. After six weeks, a repeat scan revealed disease progression with an abscess and a new disc protrusion. Transforaminal lumbar interbody fusion (TLIF) with posterior instrumentation and fusion (PSIF) was performed, and fungal smears showed septate hyphae. Beta D-glucan was 99 pg/mL and galactomannan was 0.1 ODI. Cultures later yielded Acremonium spp. and voriconazole was started empirically. This case highlights three critical points being, fungal VO must be considered in refractory spinal infections; Acremonium can infect immunocompetent hosts; and voriconazole shows efficacy against this organism. The rising incidence of nosocomial fungal infections warrants increased suspicion for atypical pathogens, even without classic risk factors. Tests like galactomannan and beta-D-glucan, although non-specific, in addition to PCR can aid diagnosis when cultures are pending. While amphotericin B remains first-line for many systemic mycoses, voriconazole’s safety profile makes it preferable for long-term treatment. This case will emphasize the rarity of Acremonium as a causative agent for osteomyelitis and discuss the importance of an accurate, quick diagnosis and treatment plan for similar cases. In addition, further studies should be conducted regarding similar case presentations.