Evaluation of a real-time PCR assay for detection and quantification of bacterial DNA directly in blood of preterm neonates with suspected late-onset sepsis

Abstract

BackgroundRapid and accurate diagnosis of neonatal sepsis is highly warranted because of high associated morbidity and mortality. The aim of this study was to evaluate the performance of a novel multiplex PCR assay for diagnosis of late-onset sepsis and to investigate the value of bacterial DNA load (BDL) determination as a measure of infection severity.MethodsThis cross-sectional study was conducted in a neonatal intensive care unit. Preterm and/or very low birth weight infants suspected for late-onset sepsis were included. Upon suspicion of sepsis, a whole blood sample was drawn for multiplex PCR to detect the eight most common bacteria causing neonatal sepsis, as well as for blood culture. BDL was determined in episodes with a positive multiplex PCR.ResultsIn total, 91 episodes of suspected sepsis were investigated, and PCR was positive in 53 (58%) and blood culture in 60 (66%) episodes, yielding no significant difference in detection rate (p = 0.17). Multiplex PCR showed a sensitivity of 77%, specificity of 81%, positive predictive value of 87%, and negative predictive value of 68% compared with blood culture. Episodes with discordant results of PCR and blood culture included mainly detection of coagulase-negative staphylococci (CoNS). C-reactive protein (CRP) level and immature to total neutrophil (I/T) ratio were lower in these episodes, indicating less severe disease or even contamination. Median BDL was high (4.1 log10 cfu Eq/ml) with a wide range, and was it higher in episodes with a positive blood culture than in those with a negative blood culture (4.5 versus 2.5 log10 cfu Eq/ml; p < 0.0001). For CoNS infection episodes BDL and CRP were positively associated (p = 0.004), and for Staphylococcus aureus infection episodes there was a positive association between BDL and I/T ratio (p = 0.049).ConclusionsMultiplex PCR provides a powerful assay to enhance rapid identification of the causative pathogen in late-onset sepsis. BDL measurement may be a useful indicator of severity of infection.Electronic supplementary materialThe online version of this article (10.1186/s13054-018-2010-4) contains supplementary material, which is available to authorized users.

Is quantitative ultrasound a measure for metabolic bone disease in preterm-born infants? A prospective subcohort study

“…We observed a decline in mcSOS in the first 6 weeks. Our finding was identical to other studies which also showed a decline in mcSOS [5,[14][15][16][17]19]. A decline in SOS during the first weeks of life might be related to a postnatal inadequate mineral intake and illness.…”

“…Up to date, most studies have measured the bone development from the admission of the infant to 36 weeks gestational age (GA). Only a few studies have reported repeated measurements of one or both parameters during a longer period [3,[14][15][16][17].…”

Culture-Negative Early-Onset Neonatal Sepsis — At the Crossroad Between Efficient Sepsis Care and Antimicrobial Stewardship

“…This may change in the future. A recent publication reports promising results using multiplex real-time PCR in late-onset neonatal sepsis with results potentially available within 4 h of blood sampling and good concordance with blood culture results ( 94 ).…”

<p>Neonatal sepsis biomarkers: where are we now?</p>

“…A larger study evaluating the clinical efficacy of the multiplex PCR approach revealed sensitivity of 77%, specificity of 81%, positive predictive value of 87%, and NPV of 68% compared with blood culture. 76 One of the greatest advantages of multiplex PCR detection is the possibility of obtaining meaningful results in as little as 4 hours. The Roche LightCycler SeptiFast Mgrade system requires 100 µL blood and can detect 20 different pathogens.…”