# Clinical and diagnostic insights into Brucella spondylitis: a comprehensive retrospective study

## TL;DR

This study examines the diagnosis and clinical features of spinal brucellosis, emphasizing the importance of tissue culture and serological tests for accurate detection.

## Contribution

The study provides new insights into the diagnostic yield of spinal tissue culture and identifies predictors of chronicity in Brucella spondylitis.

## Key findings

- Spinal tissue culture had the highest diagnostic yield (58.6%) for Brucella melitensis.
- Female sex and lumbar involvement were independent predictors of chronicity in spinal brucellosis.
- CT imaging showed bone destruction and intervertebral space stenosis as common features in affected patients.

## Abstract

This study evaluates the diagnostic value of etiological and serological testing and the clinical characteristics of spine brucellosis.

A retrospective analysis was conducted on 200 cases of spine brucellosis diagnosed between 2012 and 2025, alongside 200 non-infected controls. Bacterial cultures, clinical features, serological results (Standard Agglutination Test [SAT] and Rose Bengal Test [RBT]), and imaging findings were analyzed.

Among 200 patients with spinal involvement, Brucella melitensis was confirmed via bacterial culture in 29 cases (14.5%), with spinal tissue culture demonstrating the highest diagnostic yield (58.6%, 17/29) and a median detection time of 3 days. Spinal brucellosis constituted 25% of all brucellosis cases, exhibiting a male predominance (76.5%) and a mean patient age of 52.2 ± 10.1 years. The median hospital stay was 14.7 ± 7.8 days, while the median duration of chronic spinal brucellosis was 4.4 months (IQR: 1.5–11.5). The lumbar spine was the most frequently involved site (78.3%), followed by the cervical (8.6%) and thoracic (5.1%) regions. CT imaging revealed characteristic lesions, including bone destruction (53.0%), intervertebral space stenosis (38.5%), disc herniation (22.0%), degenerative changes (4.5%), and osteomyelitis (1.0%). Diagnostic sensitivity varied significantly across methods: blood culture (48.0%, 12/25), lumbar tissue culture (65.4%, 17/26), SAT(91.3%, 157/172), and RBT(95.9%, 165/172). Notably, all 15 serologically false-negative cases (7 by RBT and 15 by SAT) occurred in male patients. ROC curve analysis identified C-reactive protein (CRP) as a robust biomarker, with a cutoff of 1.21 mg/L yielding 85.2% sensitivity and 71.7% specificity (Z = 6.167, p < 0.001). Multivariable regression identified female sex (OR = 2.44, 95% CI: 1.20–4.96) and lumbar involvement (OR = 1.61, 95% CI: 0.75–3.46) as independent predictors of chronicity (p < 0.05). All patients received standard 3-month combination therapy with doxycycline and rifampicin, with surgical intervention required in 45.5% (91/200) of cases. Clinical outcomes were favorable across the cohort, with rare reports of severe complications.

Brucella Spondylitis, typically chronic and lumbar-predominant, presents with bone destruction, gap stenosis, and disc herniation on imaging. Diagnosis relies on lumbar tissue culture, SAT, RBT, and CT. Early diagnosis and combined medical-surgical management improve outcomes.