Application Of Xpert MTB/RIF In Rapid Diagnosis Of Spinal Tuberculosis And Rifampicin Resistance Test

Objective: To explore the application value of Xpert MTB/RIF in early diagnosis of spinal tuberculosis and rifampicin resistance test.Methods: This study collected the basic data of patients with suspected spinal tuberculosis who underwent surgical treatment at the Department of Spinal Surgery,The First Affiliated Hospital of Zunyi Medical College,Guizhou Province,from Sept.2016 to Dec.2018.Each patient took lesions in the operation area(pus,cheese-like tissue,Granulation tissue).Divided into two,one for histopathological examination,another one for tuberculosis smear,tuberculosis culture,GeneXpert test,drug sensitivity test for tuberculosis culture positive.All patients underwent regular quadruple anti-tuberculosis treatment(isoniazid 0.3g/d,Rifampicin 0.6g/d,pyrazinamide 0.75g/d,ethambutol 0.75g/d)for 2weeks before surgery.Because of the low content of Mycobacterium tuberculosis in the specimens of spinal tuberculosis,the positive rate of culture is low,so tuberculosis culture cannot be used as a diagnostic gold standard.The Composite Reference Standard(CRS)was used as a diagnostic criterion in this study to evaluate the diagnostic efficacy of Xpert MTB/RIF for detecting spinal tuberculosis.Composite Reference Standard diagnosis included: tuberculosis smear,tuberculosis culture,clinical manifestations,pathological histocytology,CT/MRI,and follow-up 3 months after enrollment.Under the Composite Reference Standard diagnostic criteria,patients were divided into 4 groups: confirmed tuberculosis group,clinical diagnosis group,suspected tuberculosis group,non-tuberculosis group.Results: In the study,98 patients were collected from Sept.2016 to Dec.2018,7 patients were excluded,and 91 patients were eventually included.There were 52 males and 39 females with an average age of 45±17.13.There were 9 cases of cervical vertebra,25 cases of T1-T9,33 cases of thoracolumbar section,and 24 cases of L3-L5.Based on the CRS criteria,82 of 91 patients were diagnosed with spinal tuberculosis.Among them,45 cases were diagnosed in the spinal tuberculosis group,23 cases were diagnosed in the spinal tuberculosis group,14 cases were suspected spinal tuberculosis group,and 9 cases were non-spine tuberculosis group.The sensitivity of Xpert,smear and culture were 74.4%(61/82),20.7%(17/82),and 54.9%(45/82),respectively,and the specificity of all three was 100%(9/9).The sensitivity of Xpert,smear and culture was statistically analyzed,P<0.05,and the difference was statistically significant.Drug sensitivity tests were performed on 45 culture-positive specimens,9 of which were resistant to RIF and 36 to which RIF was sensitive.In 9 cases of DST diagnosis of rifampicin-resistant cases,Xpert was diagnosed with rifampicin resistance in 8 cases,and Xpert was diagnosed as rifampicin in 1 case.In 36 cases of DST-diagnosed rifampic-sensitive cases,Xpert was diagnosed with rifampicin-resistant 2 cases,and Xpert was diagnosed with rifampic-sensitive 34 cases.Conclusion: The sensitivity of Xpert in diagnosis of spinal tuberculosis is higher than that of culture and smear.Xpert has higher specificity and shorter time.It can be used in early and rapid diagnosis of spinal tuberculosis.