Molecular Detection of Late-Onset Neonatal Sepsis in Premature Infants Using Small Blood Volumes: Proof-of-Concept

Background: Conventional blood culture is still the gold standard for sepsis diagnosis but results are not immediately available and pathogens are only detected in approximately 25% of cases. New molecular assays for the detection of blood stream pathogens are promising diagnostic tools. Objectives: The aim of the study was to adapt and evaluate a multiplex PCR system using 100 mu l blood. Methods: 46 blood specimens of very low birth weight infants (818 +/- 242 g) with suspected sepsis were analyzed using the Roche SeptiFast MGRADE PCR with a modified DNA extraction protocol and software handling tool for decreased blood volume requirements. Results: In the noninfected group, 5/21 infants had a positive PCR result with coagulase- negative staphylococci. All pathogens detected in the blood culture positive group (n = 15) were also detected by PCR. In addition, 4/6 patients had a positive PCR result in the clinical sepsis group (clinical and laboratory signs of sepsis but negative blood culture). Overall, the PCR was demonstrated to have a higher sensitivity (90.5%; 95% CI 68.2- 98.3%) in comparison to blood culture (71.4%; 95% CI 47.7- 87.8%) including clinical sepsis cases, even though it had a lower specificity (80.0%; 95% CI 58.7-92.4% versus 100.0%; 95% CI 83.4-100.0%). Conclusions: These first data demonstrate the usability and potential benefit of this multiplex PCR using a modified DNA extraction for the rapid detection of nosocomial sepsis in preterm infants in addition to blood culture. Copyright (C) 2013 S. Karger AG, Basel