Concurrent Tuberculosis and COVID-19 Testing from a Single Sputum Specimen for Enhanced Disease Detection

Area of Science:

• Infectious Diseases
• Public Health
• Diagnostic Microbiology

Background:

• Tuberculosis (TB) and SARS-CoV-2 share overlapping symptoms and transmission routes, complicating diagnosis.
• Integrated testing strategies are recommended for high TB burden countries to address co-infection.
• Simultaneous testing of respiratory pathogens is crucial for effective disease management.

Purpose of the Study:

• To evaluate the diagnostic accuracy of a single sputum test for both SARS-CoV-2 and Mycobacterium tuberculosis complex (MTBC).
• To assess the performance of the Xpert Xpress SARS-CoV-2 assay using a sputum swab capture method.
• To determine the prevalence of TB and TB-COVID-19 co-infection in a South African population.

Main Methods:

• A total of 1032 participants with respiratory symptoms or risk factors provided sputum for testing.
• Sputum was tested using the Xpert Xpress SARS-CoV-2 assay and Xpert MTB/RIF Ultra assay.
• Concordance analysis compared Xpress assay results with routine SARS-CoV-2 testing.

Main Results:

• SARS-CoV-2 was detected in 18% of participants, and TB in 3%.
• A 1% co-infection rate of TB and COVID-19 was observed.
• The Xpress assay demonstrated substantial agreement with routine SARS-CoV-2 testing (Kappa: 0.755).

Conclusions:

• Integrated sputum testing significantly identified cases of TB and rifampicin-resistant TB that might otherwise be missed.
• The sputum swab capture method is a reliable approach for SARS-CoV-2 detection.
• Simultaneous testing enhances the detection of co-infections and improves patient outcomes.