Introduction: Early detection of the causing microorganism and timely therapeutic intervention are crucial for improved outcome of patients with sepsis. Quite recently, we evaluated the technical and diagnostic feasibility of a commercial multiplex real-time polymerase chain reaction (PCR) (LightCycler SeptiFast® assay) for detection of blood stream infections in a cohort of intensive care unit (ICU) patients with the risk of abdominal sepsis.
Results and findings: The PCR positivity rate showed a high coincidence with systemic inflammatory response syndrome (SIRS; 75.8%). In this study, we focussed on patients from the same surgical ICU with upcoming SIRS and addressed the utility on therapeutic decision making following diagnostic application of PCR in addition and comparison to conventional microbiological and laboratory tests. In total, 104 patients on the ICU fulfilling the American College of Chest Physicians/Society of Critical Care Medicine SIRS criteria were enrolled. Blood samples were taken within 24 h of upcoming SIRS. Some 39.9% (n = 59) of the blood samples (n (Total) = 148) were positive using multiplex-PCR and 20.3% (n = 30) using conventional culture. In 11.4% of all samples, multiplex-PCR detected more than one microorganism. Among the 77 microorganisms identified by multiplex-PCR, only 25 (32.5%) could be confirmed by blood culture; an additional 17 could be confirmed by microbiological test results from other significant patient specimen. Positive blood samples independent of the detection method were characterised by significant elevated levels of procalcitonin (p < 0.05) but not C-reactive protein. In 25 cases (16.9%, n = 148), the rapid identification of involved pathogens by multiplex-PCR led to prompt adjustment of therapy.
Conclusions: Our study demonstrates improved detection of specific pathogens with a high intrinsic resistance and positive impact on therapeutic decision-making by additional multiplex-PCR-based analysis of blood samples for infectious agents in patients with new onset of SIRS. Thus, we showed for the first time that PCR test results guide clinical treatment successfully.