Use of a multiplex polymerase chain reaction system for enhanced bloodstream pathogen detection in thoracic transplantation

摘要

Background: Bloodstream infections (BSIs) constitute a frequent post-transplant complication in thoracic allograft recipients, especially during the early post-surgical period when patients are under intense immunosuppression. Thus, early and accurate identification of the responsible pathogens is of critical importance for patient survival. In this study we investigated the potential clinical utility of a multiplex real-time polymerase chain reaction (PCR) technology (SeptiFast; Roche Diagnostics) for the detection of BSIs in a cohort of thoracic allograft recipients. Methods: Our observational study included analysis of 130 blood samples from 30 thoracic allograft recipients (23 heart and 7 lung) using SeptiFast in parallel with blood culture. Samples were drawn when there were clinical and laboratory signs of BSI. The applied molecular assay has been designed to allow direct detection of a wide panel of Gram-positive and Gram-negative bacteria and fungi in blood samples. Results: Real-time PCR yielded concurrent negative and positive results with blood culture methodology in 113 (86.9%) and 5 (3.9%) samples, respectively, with 100% concordance in species identification. SeptiFast identified microorganisms in 9 (6.9%) additional samples that were negative by blood culture. The combined use of SeptiFast and blood culture during the early post-transplant period (<2 months) significantly increased the number of positive samples detected to 17.9% (14 of 78) from 7.7% (6 of 78) detected by blood culture alone (p < 0.05). SeptiFast results were available, on average, within 6 hours from sample collection. Conclusions: The PCR-based SeptiFast test is a valuable addition to the traditional blood culture method for rapid etiologic diagnosis of BSIs in thoracic transplant recipients, especially during the early post-transplant period.