Rapid molecular detection of respiratory pathogens in patients admitted with suspected community-acquired pneumonia: secondary analysis of a randomized controlled trial.

In a randomized trial, we demonstrated that implementing point-of-care (POC) PCR detection of respiratory pathogens in an emergency department (ED) setting did not change overall antibiotic use but led to more targeted treatment and a clinically relevant, albeit non-significant, reduction in length of stay. This study aimed to assess the diagnostic impact of POC-PCR testing in patients with suspected community-acquired pneumonia (CAP) in the ED. This study is a secondary analysis of a Danish multicenter randomized controlled trial (RCT) that included patients aged ≥18 years admitted to the ED between March 2021 and February 2022. In the primary trial, patients were randomly assigned to one of two parallel groups: (i) intervention group: POC-PCR in addition to standard care, or (ii) control group: standard care only (SCO). The present secondary analysis focuses exclusively on patients in the intervention group, where both POC-PCR and standard culture-based diagnostics were performed. The diagnosis of CAP was determined by an expert panel. In the intervention group, 145 patients had a lower respiratory tract (LRT) specimens analyzed using both POC-PCR and culture. POC-PCR identified notably more microorganisms compared with culture (187 vs 34). The agreement between positive results obtained by POC-PCR and culture was 6 of 19 (31.6%) for Streptococcus pneumoniae and 16 of 61 (26%) for Haemophilus influenzae. Concentrations of ≥107 copies/mL detected by POC-PCR for S. pneumoniae and H. influenzae were associated with a diagnosis of CAP. Of the 67 patients identified with S. pneumoniae and/or H. influenzae, 46 (69%) received targeted treatment, 57 (85%) received adequate treatment, and 10 (15%) received inappropriate treatment. The rapid pathogen detection by POC-PCR is likely to improve diagnostic accuracy and promote appropriate use of antibiotics in CAP patients. Our findings suggest that point-of-care (POC)-PCR testing can significantly enhance the diagnostic accuracy for CAP in the emergency department (ED), thereby facilitating more targeted and effective antimicrobial treatment. In light of growing concerns about antimicrobial resistance and the pressing need for rapid diagnostics in acute care settings, we believe our study holds considerable relevance for clinical practice in the ED.