The role of Xpert MTB/RIF assay in the diagnosis of tubercular spondylodiscitis

• DOI: 10.1007/s00586-017-5076-9
• Publication Date: 2017-04-08T09:51:28Z
• Authors: Justin Arockiaraj; Joy S. Michael; Rohit Amritanand; Kenny Samuel David; Venkatesh Krishnan
• Keywords: Molecular Typing; 03 medical and health sciences; Discitis; 0302 clinical medicine; Drug Resistance, Bacterial; Humans; Mycobacterium tuberculosis; Tuberculosis, Spinal; Sensitivity and Specificity; Retrospective Studies; 3. Good health

This study aims to assess the accuracy of the Xpert MTB/RIF assay in the diagnosis of tubercular spondylodiscitis and to identify its role in detecting Rifampicin resistance in patients with infective spondylodiscitis.A retrospective study including 348 patients suspected to have infective spondylodiscitis was done. Tissue/pus samples obtained were sent for culture, histopathology and Xpert MTB/RIF assay. All patients who were confirmed to have tubercular spondylodiscitis and those patients who were suspected on clinico-radiological basis were also treated with anti-tuberculous chemotherapy for a period of 9 months. The efficacy of the Xpert MTB/RIF assay was assessed in terms of sensitivity and specificity when compared to culture, histopathology, and Composite reference standard (CRS).During this study period of 24 months, a total of 348 patients were treated for infective spondylodiscitis. 254 patients were treated for tuberculosis following a smear positivity, culture positivity, and histopathology report or empirically based on clinico-radiological findings. The sensitivity and specificity of the Xpert MTB/RIF assay when compared to culture were 88.4 and 63.7%, respectively. When compared to both culture and histopathology reports it was 80.9 and 80.6%. The sensitivity and specificity of the Xpert MTB/RIF assay when compared to composite reference standard were 71.2 and 100%, respectively. The sensitivity of the assay to detect Rifampicin resistance was 100%. The prevalence of Rifampicin resistance was 5.1%.This study recommends Xpert MTB/RIF assay for early detection of Mycobacterium tubercular spondylodiscitis and Rifampicin resistance.