Feasibility and sensitivity of saliva GeneXpert MTB/RIF Ultra for tuberculosis diagnosis in adults in Uganda
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The objective of this prospective observational study carried out at China-Uganda Friendship Hospital-Naguru in Kampala, Uganda, was to determine the performance of GeneXpert MTB/RIF Ultra (Xpert Ultra) molecular testing on saliva for active tuberculosis (TB) disease among consecutive adults undergoing TB diagnostic evaluation who were Xpert Ultra positive on sputum. We calculated sensitivity to determine TB diagnostic performance in comparison to a composite reference standard of Mycobacterium tuberculosis liquid and solid cultures on two spot sputum specimens. Xpert Ultra on a single saliva sample had a sensitivity of 90% (95% confidence interval [CI], 81 to 95%) relative to the composite sputum culture-based reference standard, similar to the composite sensitivity of 87% (95% CI, 77 to 94%) for fluorescence microscopy (FM) for acid-fast bacilli on two sputum smears. The sensitivity of salivary Xpert Ultra was 24% lower (95% CI for difference, 2 to 48%; P = 0.003) among persons living with HIV (71%; 95% CI, 44 to 90%) than among persons living without HIV (95%; 95% CI, 86 to 99%) and 46% higher (95% CI, 14 to 77%; P < 0.0001) among FM-positive (96%; 95% CI, 87 to 99%) than among FM-negative (50%; 95% CI, 19 to 81%) patients. The semiquantitative Xpert Ultra grade was systematically higher in sputum than in a paired saliva sample from the same patient. In conclusion, molecular testing of saliva for active TB diagnosis was feasible and almost as sensitive as molecular testing of sputum in a high TB burden setting.
Byanyima , P , Kaswabuli , S , Musisi , E , Nabakiibi , C , Zawedde , J , Sanyu , I , Sessolo , A , Andama , A , Worodria , W , Huang , L & Davis , J L 2022 , ' Feasibility and sensitivity of saliva GeneXpert MTB/RIF Ultra for tuberculosis diagnosis in adults in Uganda ' , Microbiology Spectrum , vol. Early Online , e00860-22 . https://doi.org/10.1128/spectrum.00860-22
Copyright © 2022 Byanyima et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
DescriptionThis work was supported in part by NIH D43 TW009607 (J.L.D.), the Pulmonary Complications of AIDS Research Training (PART) program, and NIH K24 HL087713 (L.H.) and R01 HL128156 (L.H.).
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