Results and Relevance of Molecular Detection of Pathogens by SeptiFast – A Retrospective Analysis in 75 Critically Ill Children

Abstract

Background:

Sepsis is a common cause of death in children. Early detection of bloodstream pathogens is crucial for the appropriate antibio­tic treatment. Blood cultures (BC) are the gold standard test used for detection. Recently, additional molecular detection methods of microbial DNA by multiplex PCR (SeptiFast, SF) have become available.

Aim:

Our retrospective study was aimed to compare results of BC to those of SF regarding results and therapeutic relevance.

Method:

We identified a total of 110 SF samples in 75 patients with suspected systemic infection by retrospective chart review. Each patient underwent SF and BC testing simultaneously.

Results:

The initial analysis displayed no statistical significant difference in positive SF results compared to BC (p=0.19): in 26 of 110 samples (24%) microbial DNA was found. 19 BC (17%) showed microbial growth. 14 samples were positive in SF but negative in BC (13%). In patients who were pretreated with antibiotics (n=97) pathogens were identified in 24 samples by SF (25%) but only in 11 samples by BC (11%). Based on the clinical presentation and the spectrum of bacterial isolates 3 BC were considered contaminated. Considering this, SF yielded pathogens significantly more often than BC in the overall study population (p=0.04). SF results were available at least 31 h before BC results. Based on SF result antibiotic therapy was adjusted in 14 patients (13%).

Conclusion:

Molecular detection of pathogens by SF was faster and more frequently positive than BC. We have therefore demonstrated that SF might be superior to BC in testing for bloodstream pathogens. Prospective multicentric studies are required to determine whether this hypothesis can be maintained.

Zusammenfassung

Hintergrund:

Sepsis ist eine häufige Todesursache bei Kindern. Zur gezielten Behandlung ist ein schneller Erregernachweis erforderlich. Eine diagnostische Ergänzung zur Blutkultur (BK) bietet der molekulargenetische Nachweis von Erreger-DNA mittels Multiplex PCR.

Ziel:

Ziel unserer retrospektiven Analyse war der Vergleich von BK und PCR bezüglich Ergebnis und dessen Relevanz.

Methode:

Uns standen dazu Daten aus 110 Proben von 75 Patienten mit Symptomen einer Infektion zur Verfügung, die zeitgleich mittels BK und des molekulargenetischen Testsystems SeptiFast (SF) untersucht wurden.

Ergebnisse:

Mittels SF gelang ein Erregernachweis nicht statistisch signifikant häufiger (P=0,19): In 26 von 110 (24%) Proben war mikrobielle DNA nachweisbar, während 19 BK (17%) ein Keimwachstum zeigten. 14-mal war das SF Ergebnis bei negativer BK positiv (13%). In der Untergruppe der antibiotisch vorbehandelten Patienten (n=97) gelang mittels SF 24-mal (25%), mittels BK 11-mal (11%) ein Erregernachweis. Unter Berücksichtigung von Klinik und Art des nachgewiesenen Keims wurden 3 positive BK als kontaminiert gewertet. Es ergibt sich damit für die gesamte Studienpopulation ein signifikant häufigerer Keimnachweis im SF gegenüber BK (P=0,04). Das SF-Ergebnis lag immer mindestens 31 h vor dem Kulturergebnis vor. Eine Therapie­änderung aufgrund des molekulargenetischen Befundes folgte bei 14 Patienten (13%).

Schlussfolgerung:

Bei unseren Patienten war die molekulargenetische Erregerdiagnostik mittels SF schneller und häufiger positiv als die BK. Prospektive multizentrische Studien sollten den scheinbaren Nutzen weiter untersuchen.

Key words

SeptiFast - blood culture - pediatric - antibiotic therapy

Schlüsselwörter

SeptiFast - Blutkultur - Pädiatrie - antibiotische Therapie

• References

• 1 Berger A, Altiok I, Mechtler T et al. Adaption of the Roche Septifast system for the early detection of neonatal sepsis in very low birthweight infants. KlinPadiatr 2010; 222 (Suppl. 1) S4 DOI: 10.1055/s-0030-1261288.
• 2 Brierley J, Carcillo J, Choong K et al. Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine. Crit Care Med 2007; 37: 666-688
• 3 Connell TG, Rele M, Cowley D et al. How reliable is a negative blood culture result? volume of blood submitted for culture in routine practice in a children’s hospital. Pediatrics 2007; 119: 891-896
• 4 Dierkes C, Ehrenstein B, Siebig S et al. Clinical impact of a commercially availible multiplex PCR system for rapid detection of pathogens in patients with presumed sepsis. BMC Infect Dis 2009; 9: 126
• 5 Goldstein B, Giroir B, Randolph A. International pediatric sepsis consensus conference: definitions for sepsis and organ dysfunction in pediatrics. Pediatr Crit Care Med 2005; 6: 2-8
• 6 Haase R, Lieser U, Kramm C et al. Management of oncology patients admitted to the paediatric intensive care unit of a general children’s hospital – a single center analysis. Klin Paediatr 2011; 223: 142-46
• 7 Lehmann LE, Hunfeld KP, Steinbrucker M et al. Improved detection of blood stream pathogens by real-time PCR in severe sepsis. Intensive Care Med 2010; 36: 49-56
• 8 Louie RF, Tang Z, Albertson TE. Multiplex polymerase chain reaction detection enhancement of bacteremia and fungemia. Crit Care Med 2008; 36: 1487-1492
• 9 Lucignano B, Ranno S, Liesenfeld O et al. Multiplex PCR allows rapid and accurate diagnosis of bloodstream infections in newborns and children with suspected sepsis. L Clin Microbiol 2011; 49: 2552-2558
• 10 Mancini N, Clerici D, Diotti R et al. Molecular diagnosis of sepsis in neutropenic patients with haematological malignancies. J Med Microbiol 2008; 57: 601-604
• 11 Tschiedel E, Steinmann J, Buer J et al. Anwendung von LightCycler SeptiFast bei pädiatrischen Patienten. Klin Padiatr 2010; 222 (Suppl. 1) S25 DOI: 10.1055/s-0030-1261359.
• 12 Vince A, Zidovec Lepej S, Baršić B et al. LightCycler SeptiFast assay as atool for the rapid diagnosis of sepsis in patients during antimicrobial therapy. J Med Microbiol 2007; 57 (Pt10) 1306-1307
• 13 von Lilienfeld-Toal M, Lehmann LE, Raadts AD et al. Utility of a commercially available multiplex real-time PCR assay to detect bacterial and fungal pathogens in febrile neutropenia. J Clin Microbiol 2009; 47: 2405-2410
• 14 Wallet F, Nseir S, Baumann L et al. Preliminary clinical study usng a multiplex real-time PCR test for the detection of bacterial and fungal DNA directly in blood. Clin Microbiol Infect [epub ahead of print] 2009;
• 15 Watson RS, Carcillo JA, Linde-Zwirble WT et al. The epidemiology of severe sepsis in children in the United States. Am J Respir Crit Care Med 2003; 167: 695-701
• 16 Westh H, Lisby G, Breysse F et al. Multiplex real-time PCR and blood culture for identification of bloodstream pathogens in patients with suspected sepsis. Clin Microbiol Infect 2009; 15: 544-551