A comparative study on the value of Xpert MTB/RIF and T-SPOT.TB tests in the diagnosis of bone and joint tuberculosis.

We evaluated the application value of Xpert MTB/RIF and T-SPOT.TB in the diagnosis of bone and joint tuberculosis. One hundred two patients with suspected bone and joint tuberculosis (BJTB) were admitted to Zhengzhou Orthopaedics Hospital, Henan, China from April 2018 to February 2019. The Xpert MTB/RIF and T-SPOT.TB tests were performed using pus specimens and peripheral blood, respectively. The diagnostic performance of Xpert MTB/RIF and T-SPOT.TB tests was evaluated on the basis of the composite reference standard (CRS). A Total of 73 suspected BJTB were enrolled and categorized, including 12 confirmed BJTB, 27 probable BJTB and 34 non-BJTB. When CRS was used as the reference, the specificity, PPV and NLR values of the Xpert MTB/RIF assay were significantly higher than those of the T-SPOT.TB assay (97.1% vs. 82.4%, p < 0.05; 96.7% vs. 85.4%, p < 0.05; 0.26 vs. 0.12, p < 0.05). However, the sensitivity, NPV and PLR values of the T-SPOT. TB assay were significantly higher than those of the Xpert MTB/RIF assay (89.7% vs. 74.4%, p < 0.05; 87.5% vs. 76.7%, p < 0.05; 5.08 vs. 2.52, p < 0.05). The AUCs from Xpert MTB/RIF and T-SPOT. TB tests were 0.857 and 0.860, respectively. However, the difference was not statistically significant. The Xpert MTB/RIF and T-SPOT. TB tests demonstrated medium concordance in diagnosing BJTB. The sensitivity of T-SPOT.TB test combined with the specificity of Xpert MTB/RIF not only shorten the time of diagnosis but also improve the accuracy of diagnosis of BJTB and reduce the misdiagnosis rate. Therefore, they are useful for early diagnosis of BJTB.

Zhou Z ，Zheng Y ，Wang L 《-》

Diagnostic accuracy of the Xpert MTB/RIF assay for bone and joint tuberculosis using tissue specimens.

To evaluate the diagnostic accuracy of the Xpert MTB/RIF assay for bone and joint tuberculosis (BJTB) using tissue specimens, and to compare the diagnostic accuracy of different types of tissue specimens. This study involved 242 patients admitted with suspected BJTB between May 2018 and March 2020. The Xpert MTB/RIF assay was performed on surgically excised tissue. Diagnostic accuracy of the Xpert MTB/RIF assay was evaluated by culture, histopathology and a composite reference standard (CRS). One hundred and seventy-five patients were excluded (91 based on the exclusion criteria, and 84 as pus specimens were used instead of tissue specimens). Of the 67 patients enrolled, 14 were confirmed as BJTB, 20 as probable BJTB, 11 as possible BJTB, and 22 as non-BJTB. Using culture as the reference standard, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the curve (AUC) of the Xpert MTB/RIF assay were 92.9% (88.2-97.6%), 62.3% (56.1-68.5%), 39.4% (33.2-45.6%), 97.1% (92.3-100.0%), 2.464 (1.077-3.851), 0.114 (0.025-0.203) and 0.776 (0.654-0.897), respectively. When histopathology was used as the reference standard, the Xpert MTB/RIF assay had sensitivity, specificity, PPV, NPV, PLR, NLR and AUC of 79.3% (73.5-85.1%), 73.7% (67.8-79.6%), 69.7% (63.8-75.6%), 82.4% (76.5-88.3%), 3.015 (1.184-4.846), 0.281 (0.141-0.421) and 0.765 (0.646-0.884), respectively. Sensitivity, specificity, PPV, NPV, PLR, NLR and AUC obtained when using CRS as the reference were 73.3% (67.9-78.7%), 100.0% (100.0-100.0%), 100.0% (100.0-100.0%), 64.7% (58.5-70.9%), +∞, 0.267 (0.129-0.405) and 0.867 (0.781-0.952), respectively. Tissue samples were classified, and the positive rate of the Xpert MTB/RIF assay for BJTB using granulation tissue specimens was found to be significantly higher than that for caseous necrotic tissue, sequestrum and other necrotic connective tissues (P < 0.05). The Xpert MTB/RIF assay showed high sensitivity and specificity for the diagnosis of BJTB from tissue specimens.

Zhou Z ，Zheng Y ，Wang L 《-》

Diagnostic efficiency of Xpert MTB/RIF assay for osteoarticular tuberculosis in patients with inflammatory arthritis in China.

Li Y ，Jia W ，Lei G ，Zhao D ，Wang G ，Qin S ... -  《PLoS One》

Xpert MTB/RIF and GenoType MTBDRplus assays for the rapid diagnosis of bone and joint tuberculosis.

Bone and joint tuberculosis (BJTB) constitutes about 10-20% of the extrapulmonary tuberculosis (EPTB) cases in China. The GenoType MTBDRplus assay (MTBDR) has been endorsed by the World Health Organization (WHO) for the diagnosis of pulmonary TB (PTB), while the Xpert MTB/RIF assay (Xpert) has also been endorsed by the WHO for the diagnosis of both PTB and EPTB. The diagnostic utility of these two techniques for BJTB was investigated prospectively. Sixty pus specimens were obtained from orthopedic patients. Smear, culture, Xpert, and MTBDR assays were performed for each specimen, and MGIT 960-based drug susceptibility testing (DST) was conducted for all of the isolates recovered. The diagnostic efficiency of Xpert and MTBDR was evaluated on the basis of bacteriological examination and the composite reference standard (CRS). Fifty of the 60 patients were considered to have BJTB according to the CRS. The sensitivities of smear, culture, Xpert, and MTBDR were 26% (13/50), 48% (24/50), 82% (41/50), and 72% (36/50) respectively, while the specificities of all of the tests were 100% (10/10). Xpert was 100% concordant with MGIT 960-based DST for the detection of rifampicin resistance. MTBDR had a sensitivity of 83.3% and a specificity of 100% for the detection of rifampicin resistance and a sensitivity of 85.7% and specificity of 100% for the detection of isoniazid resistance. With their high sensitivities, short turnaround times, and ability to diagnose TB and detect drug resistance simultaneously, both Xpert and MTBDR are feasible as diagnostic tools for BJTB in clinical practice.

Gu Y ，Wang G ，Dong W ，Li Y ，Ma Y ，Shang Y ，Qin S ，Huang H ... -  《-》

Evaluation of targeted sequencing for pathogen identification in bone and joint infections: a cohort study from China.

Bone and joint tuberculosis (BJTB) is a distinct variant of tuberculosis in which clinical diagnosis often leads to relative misdiagnosis and missed diagnoses. This study aimed to evaluate the diagnostic accuracy of the targeted nanopore sequencing (TNPseq) assay for BJTB patients in China. The study enrolled a cohort of 163 patients with suspected BJTB. Diagnostic testing was performed using the TNPseq assay on samples including punctured tissue, pus, and blood. The diagnostic accuracy of the TNPseq assay was then compared with that of the T-SPOT and Xpert MTB/RIF assays. TNPseq exhibited superior performance in terms of accuracy, demonstrating a sensitivity of 76.3% (95% CI: 71.0-81.6%) and a specificity of 98.8% (95% CI: 93.5-100%) in clinical diagnosis. When evaluated against a composite reference standard, TNPseq demonstrated a sensitivity of 74.4% (95% CI: 69.3-79.5%) and a specificity of 98.8% (95% CI: 93.7-100%). These results exceed the performance of both the T-SPOT and Xpert MTB/RIF tests. Notably, TNPseq demonstrated high specificity and accuracy in puncture specimens, with a sensitivity of 75.0% (95% CI: 70.2-79.8%) and a specificity of 98.3% (95% CI: 92.7-100%), as well as in pus samples, with a sensitivity of 83.3% (95% CI: 78.6-88.1%) and a specificity of 100% (95% CI: 100-100%). Additionally, TNPseq facilitated the detection of mixed infection scenarios, identifying 20 cases of bacterial-fungal co-infection, 17 cases of bacterial-viral co-infection, and two cases of simultaneous bacterial-fungal-viral co-infection. TNPseq demonstrated great potential in the diagnosis of BJTB due to its high sensitivity and specificity. The ability of TNPseq to diagnose pathogens and detect drug resistance genes can also guide subsequent treatment. Expanding the application scenarios and scope of TNPseq will enable it to benefit more clinical treatments.

Zhang Q ，Ding Y ，Ren Q ，Zhang F ，Lyu G ，Lu T ，Song Z ，Wang Q ，Cheng Y ，Wang J ，Gu H ... -  《Annals of Clinical Microbiology and Antimicrobials》