Application of Droplet Digital PCR in Sputum Samples in Myasthenia Gravis Patients with Pneumonia.

BACKGROUND

Due to the rapid progression of the pneumonia in patients with Myasthenia gravis (MG), faster pathogen detection techniques are needed. The droplet digital polymerase chain reaction (ddPCR) has the ability to detect pathogens in about 3 h. Thus, this study focused on application of ddPCR in sputum samples in the MG patients with pneumonia and analyzed the association between ddPCR and other laboratory results.

METHODS

We prospectively enrolled 22 MG inpatients with pneumonia and collected 24 sputum samples. All samples were analyzed using traditional culture, ddPCR and metagenomic next-generation sequencing (mNGS) in parallel. Clinical outcomes during hospitalization were documented.

RESULTS

Among the 24 sputum samples collected from 22 MG patients, ddPCR achieved a 100% positivity rate with the identification of bacteria in all 24 samples, while mNGS also demonstrated a high detection rate, identifying bacteria in 23 of 24 samples (95.8%), and additionally detecting viral and fungal pathogens across multiple cases. In 4 patients with negative sputum culture results, pathogens were identified by both ddPCR and mNGS.

CONCLUSION

The ddPCR demonstrated rapid and sensitive identification of predefined bacterial targets and drug-resistance genes, making it suitable for initial diagnostic screening and timely clinical decision-making in MG patients with pneumonia. The speed of ddPCR detection is faster than mNGS and traditional culture, and the results are similar to mNGS and culture, with good consistency.