Bacteroides fragilis vertebral osteomyelitis: A rare clinical entity

Area of Science:

• Infectious Diseases
• Microbiology
• Spinal Surgery

Background:

• Vertebral osteomyelitis is often caused by aerobic bacteria via bloodstream infections.
• Anaerobic osteomyelitis, involving 2-5% of cases, usually stems from contiguous infections, often polymicrobial, breaching the gut barrier.
• Bacteroides fragilis is a common anaerobic bacterium, but rarely implicated as a direct cause of vertebral osteomyelitis.

Observation:

• Two distinct cases of vertebral osteomyelitis caused by Bacteroides fragilis are presented.
• Unlike typical presentations, these cases lacked a history of intra-abdominal or pelvic infections, or prior medical interventions.
• The vertebral bodies were the primary site of infection in both instances.

Findings:

• Bacteroides fragilis can be an etiological agent in vertebral osteomyelitis, even without apparent contiguous spread from abdominal or pelvic sources.
• The diagnosis was confirmed through microbiological analysis of the affected vertebral tissue.
• These findings challenge the conventional understanding of Bacteroides fragilis's role in vertebral infections.

Implications:

• Early identification of Bacteroides fragilis as the causative agent is critical for effective treatment strategies.
• Timely and appropriate antimicrobial therapy may prevent the need for neurosurgical or orthopedic interventions.
• This case series expands the differential diagnosis for vertebral osteomyelitis, particularly in the context of anaerobic infections.