The cocktail infection: anaerobic and aerobic co-Infections in tubercular vertebral osteomyelitis [version 2; peer review: 1 approved with reservations, 2 not approved]

Background: Anaerobic organisms have been known to have an association with dental infections, bacteremia, endocarditis and soft tissue infections. However, anaerobic isolation from bone and joint infections are relatively rare. Sparse literature has been found on reports of anaerobic osteomyelitis. There is no literature reported on anaerobic osteomyelitis complicating Tuberculosis of spine. Case Report: We report two cases of tuberculosis of spine complicated by aerobic and anerobic infections. The first is a case of a young female who presented with chronic lower backache and fever. Examination revealed a lumbar scoliosis with paraspinal tenderness. Magnetic resonance imaging (MRI) of the spine showed lumbar spondylodiscitis with multiple abscesses. There were air-fluid levels noted in the abscesses. The pus sent for CBNAAT (cartridge based nucleic acid amplification test) was positive. Further the cultures also grew Escherichia coli (aerobic) Bacteroids fragilis and Peptoniphilus asachrolyticus (anaerobic) organisms. She improved with a course of intravenous antibiotics and decompression surgery. The second case is a middle aged man who presented with chronic neck pain and fever. Examination revealed kyphosis of the neck with spasm of the neck muscles and midline tenderness. MRI showed C4-5 cervical spondylodiscitis with parapharyngeal collections showing air-fluid levels. The pus culture showed Streptococcus constellatus (aerobic) and Prevotella sps. (anaerobic). The CBNAAT report was positive for Mycobacterium tuberculosis. The patient was treated with intravenous antibiotics and cervical decompression. Conclusion: Though tubercular vertebral osteomyelitis (TVO) is usually a diagnosis in itself, it should not hinder us from considering secondary infections (both aerobic and anaerobic) complicating the osteomyelitis. Further, the presence of air-fluid levels on imaging studies and the presence of foul smell during operative exploration of the spine must arouse the suspicion of an anaerobic co-infection. Isolation and treatment of these organisms are crucial as they may hamper the clinical outcome of the primary TVO.