Validation of a clinical scoring system to differentiate mycobacterial and bacterial causes of spondylodiscitis: a retrospective cohort study from Kerala, India.

BACKGROUND

Mycobacterial and bacterial spondylodiscitis require distinct therapeutic approaches. However, microbiological diagnosis is often delayed or unavailable in resource-limited settings. This study aimed to validate a clinical scoring system developed in a prior retrospective cohort study in Karnataka (India) to differentiate these aetiologies.

METHODS

We conducted a retrospective cohort study of patients with microbiologically confirmed spondylodiscitis admitted between January 2017 and August 2024 in a tertiary care centre in Kerala, India. Demographic, clinical, laboratory, imaging, and treatment data were compared between the two groups, and the scoring system's diagnostic performance was assessed.

RESULTS

Of 151 patients with infectious spondylodiscitis, 73 patients with community-acquired microbiologically confirmed infection were included. Of these, 32 (44%) had mycobacterial, and 41 (56%) had bacterial spondylodiscitis [ (37%), (11%), (11%), spp (4.1%), spp (1.4%)]. The scoring system demonstrated good diagnostic accuracy for bacterial aetiology (AUC: 0.78; 95% CI: 0.67-0.88). Mycobacterial cases were younger, had longer symptom duration, lower C-reactive protein and leukocyte counts, and more frequent vertebral height loss on imaging. The rate of clinical improvement was similar between groups.

CONCLUSIONS

The validated clinical scoring system reliably distinguishes mycobacterial from bacterial spondylodiscitis and may guide empirical management in settings where timely microbiological diagnosis is not feasible.