SMaRT-PCR: sampling using masks and RT-PCR, a non-invasive diagnostic tool for paediatric pulmonary TB

Area of Science:

• Medical Diagnostics
• Microbiology
• Pediatric Pulmonology

Background:

• Paediatric tuberculosis (TB) diagnosis faces challenges with invasive sampling and low sensitivity of current methods.
• Developing non-invasive diagnostic tools is crucial for improving TB detection in children.
• Bioaerosol sampling offers a potential non-invasive alternative for TB diagnosis.

Purpose of the Study:

• To evaluate the diagnostic potential of non-invasive bioaerosol sampling using SMaRT-PCR for paediatric TB.
• To compare the sensitivity and specificity of SMaRT-PCR with standard diagnostic methods for TB in children.
• To assess the feasibility of using mask sampling for TB detection in a pediatric cohort.

Main Methods:

• Exhaled bioaerosols were collected from 51 children (aged 2-15 years) using modified N-95 masks during a talk-cough-breathe process.
• Mask samples were analyzed using in-house reverse transcriptase-polymerase chain reaction (RT-PCR) for 16s and rpoB RNA transcripts.
• Additional samples were tested with Xpert MTB/RIF and Xpert MTB/RIF Ultra assays.

Main Results:

• SMaRT-PCR demonstrated high sensitivity (96% for either gene, 75% for both) for detecting TB in treatment-naïve children, comparable to standard methods (71%).
• Specificity of SMaRT-PCR was high at 95% when detecting both genes, outperforming single-gene detection (85%).
• Mask sampling with Xpert assays showed low sensitivity (13%).

Conclusions:

• Bioaerosol testing via SMaRT-PCR presents a promising, non-invasive approach for diagnosing paediatric TB.
• The simplicity of mask sampling suggests potential for point-of-care applications.
• RNA transcript-based detection may enhance TB diagnostic sensitivity in children, warranting further clinical validation.