Point-of-Care Testing by Multiplex-PCR in Different Compartments in Suspected Lower Respiratory Tract Infection After Lung Transplantation-Results of a Prospective Study.

Background: Respiratory tract infections (RTIs) are a leading cause of morbidity and mortality following lung transplantation (LTx). This study evaluated a point-of-care multiplex-PCR testing system (POCTmPCR) for pathogen detection in various respiratory samples from LTx recipients.

Methods: In a prospective single-center study, LTx recipients with RTI undergoing bronchoscopy were enrolled. Samples from bronchoalveolar lavage (BAL), sputum, and nasopharyngeal swabs (NPS) were analyzed by POCTmPCR in conjunction with conventional diagnostics. The primary study endpoint was the concordance of POCTmPCR results between samples (DRKS00032359).

Results: Fifty participants with a median age of 48 years were included; 28 (56%) were previously colonized. Using POCTmPCR, 44 bacterial pathogens were identified in BAL from 30 patients, 49 in sputum (30 patients), and 33 in NPS (17 patients). POCTmPCR identified 24 viral pathogens in BAL from 20 patients, 22 pathogens in sputum of 19 patients, and 19 in NPS of 19 patients. For viral POCTmPCR, sensitivity and specificity compared to BAL were 84% and 97% in sputum, and 80% and 97% in NPS, respectively. For bacterial POCTmPCR, sensitivity and specificity were 80% and 67% in sputum, and 37% and 85% in NPS, respectively. POCTmPCR in comparison to conventional workup had a sensitivity of 89% and 80% and specificity of 75% and 76% for viral and bacterial pathogens, respectively.

Conclusion: POCTmPCR in nasal swabs and sputum may serve as an alternative to BAL for detecting respiratory viruses. Performance for bacterial detection in noninvasive samples was lower. The POCTmPCR system used lacks detection for SARS-CoV-2 and Aspergillus spp.