Clinical impact of a commercially available multiplex PCR system for rapid detection of pathogens in patients with presumed sepsis

Abstract

BackgroundTimely identification of pathogens is crucial to minimize mortality in patients with severe infections. Detection of bacterial and fungal pathogens in blood by nucleic acid amplification promises to yield results faster than blood cultures (BC). We analyzed the clinical impact of a commercially available multiplex PCR system in patients with suspected sepsis.MethodsBlood samples from patients with presumed sepsis were cultured with the Bactec 9240™ system (Becton Dickinson, Heidelberg, Germany) and aliquots subjected to analysis with the LightCycler® SeptiFast® (SF) Test (Roche Diagnostics, Mannheim, Germany) at a tertiary care centre. For samples with PCR-detected pathogens, the actual impact on clinical management was determined by chart review. Furthermore a comparison between the time to a positive blood culture result and the SF result, based on a fictive assumption that it was done either on a once or twice daily basis, was made.ResultsOf 101 blood samples from 77 patients, 63 (62%) yielded concordant negative results, 14 (13%) concordant positive and 9 (9%) were BC positive only. In 14 (13%) samples pathogens were detected by SF only, resulting in adjustment of antibiotic therapy in 5 patients (7,7% of patients). In 3 samples a treatment adjustment would have been made earlier resulting in a total of 8 adjustments in all 101 samples (8%).ConclusionThe addition of multiplex PCR to conventional blood cultures had a relevant impact on clinical management for a subset of patients with presumed sepsis.

Microbiological Diagnosis of Sepsis: Polymerase Chain Reaction System Versus Blood Cultures

“…17,19 According to previous studies, the use of PCR diagnostic techniques such as SeptiFast could help increase this percentage significantly. 10,11,20,21 In this study, we observed that blood cultures that showed growth were obtained in only 28.6% of the evaluated patients, which is largely consistent with the findings reported for other studies. 18 In comparison with SeptiFast, blood culture showed moderate sensitivity at 72 hours (53.7%); however, this sensitivity is higher than that observed in similar studies.…”

“…8 The LightCycler SeptiFast Test (SeptiFast, Roche Diagnostics) is a multipathogen probe-based real-time polymerase chain reaction (PCR) system targeting DNA sequences of bacteria and fungi in blood samples, and it is considered to be a potentially valuable complementary tool in the management of patients with suspected sepsis. [9][10][11] However, the superiority of the SeptiFast system to blood culture for identifying pathogens in sepsis remains unclear. A recently published meta-analysis 12 of 34 studies with a total of 6012 patients showed suboptimal sensitivity of SeptiFast.…”

Comparison of three different commercial PCR assays for the detection of pathogens in critically ill sepsis patients

“…This is comparable to the results of some earlier studies [26,27]. In studies performed in emergency departments, the rates of positivity were generally higher.…”

Detection of microbial DNAemia: does it matter for sepsis management?

“…This commercial real-time PCR assay detects 25 bacterial and fungal species or genera that account for [90% of bloodstream pathogens [7]. Observational studies comparing its accuracy to blood culture have indicated a sensitivity ranging between 60 and 95% and specificity between 74 and 83% in hemato-oncology, emergency and critical care settings [9][10][11][12]. PCR took a reported median time of 7-18 h from sampling to result.…”

“…In these studies, many febrile episodes were associated with pathogen DNAemia detected by PCR but not by blood culture. Many of these ''false-positive'' PCR results were deemed clinically significant, based on retrospective patient chart review or subsequent isolation of the pathogen from relevant clinical samples [9][10][11][12].…”