Mycobacterium tuberculosis detection from oral swabs with Xpert MTB/RIF ULTRA: A pilot study

Abstract

Objective: Diagnostic testing for tuberculosis depends on microbiological detection of Mycobacterium tuberculosis (Mtb) in sputum. For patients unable to expectorate sputum, such as children and individuals living with HIV, this poses barriers to rapid diagnosis and treatment initiation. Therefore, this study aimed to use oral swabs as an alternative sample type for Mtb detection via molecular testing. Results: In a pilot study, we aimed to evaluate sensitivity of Mtb detection via oral swabs using Xpert MTB/RIF ULTRA. We enrolled 33 TB cases and 30 controls from Lima, Peru, and detected Mtb from oral swabs with a sensitivity of 45% (95% confidence interval (CI) 29-62%) and specificity of 100% (95% CI 89-100%) using liquid culture of sputum as reference test. Our current protocol will need optimization, but these results support future exploration of the use of oral swabs for Mtb detection.