Comprehensive molecular testing for respiratory pathogens in community-acquired pneumonia.
Clin Infect Dis. 2016 Jan 7;
Authors: Gadsby NJ, Russell CD, McHugh MP, Mark H, Conway Morris A, Laurenson IF, Hill AT, Templeton KE
Abstract
BACKGROUND: The frequent lack of a microbiological diagnosis in community-acquired pneumonia (CAP) impairs pathogen-directed antimicrobial therapy. This study assessed the use of comprehensive multi-bacterial, multi-viral molecular testing, including quantification, in adults hospitalized with CAP.
METHODS: Clinical and laboratory data were collected for 323 adults with radiologically-confirmed CAP admitted to two UK tertiary care hospitals. Sputum (96%) or endotracheal aspirate (4%) specimens were cultured as per routine practice and also tested with fast multiplex real-time PCR assays for 26 respiratory bacteria and viruses. Bacterial loads were also calculated for eight bacterial pathogens. Appropriate pathogen-directed therapy was retrospectively assessed using national guidelines adapted for local antimicrobial susceptibility patterns.
RESULTS: Comprehensive molecular testing of single lower respiratory tract (LRT) specimens achieved pathogen detection in 87% of CAP patients; compared to 39% with culture-based methods. H. influenzae and S. pneumoniae were the main agents detected in CAP, along with a wide variety of typical and atypical pathogens. Viruses were present in 30% of cases; and 82% of these were co-detections with bacteria. Most (85%) patients had received antimicrobials in the 72-hours before admission; of these, 78% had a bacterial pathogen detected by PCR but only 32% were culture-positive (p<0.0001). Molecular testing had the potential to enable de-escalation in number and/or spectrum of antimicrobials in 77% of patients.
CONCLUSIONS: Comprehensive molecular testing significantly improves pathogen detection in CAP, particularly in antimicrobial-exposed patients, and requires only a single LRT specimen. It also has the potential to enable early de-escalation from broad-spectrum empirical antimicrobials to pathogen-directed therapy.
PMID: 26747825 [PubMed - as supplied by publisher]