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Molecular diagnosis of septicaemia: SeptiFast vs. blood culture

Abstract number: P1817

Kotnik M., Luger C., Huber-Wechselberger A., Stumvoll S., Bocksrucker A., Sammer B., Metz-Gercek S., Apfalter P., Mittermayer H.

Objective: Rapid diagnosis of bacteraemia is of prime importance in the management of febrile patients. The SeptiFast (SF) blood assay detects 19 bacterial and 6 fungal pathogens in blood samples by nucleic acid amplification. Molecular biology methods provide faster results than conventional culture methods, hence SF allows a rapid diagnosis of septic episodes. We evaluated SF in comparison to blood culture in patients with suspected septicaemia.

Methods: Blood samples for SF were processed according to the manufacturer's specification. In short whole blood sample undergoes mechanical lysis with ceramic beads. In further purification steps DNA is extracted. PCR is carried out in three parallel real time reactions. The amplicons are detected by fluorescence emission. Blood cultures were processed according to the SOP`s of the respective laboratories. Over a period of two and a half years we tested 440 patients and compared SeptiFast (SF) results to BC.

Results: For 384 out of 440 samples complete data were available. 82 (21.4%) of samples were positive in BC, 122 (31.8%) in SF. Of 122 detected pathogens by SF, 65 were isolated from BC. Differing results between the two methods were obtained in 45 instances, BC was only positive in 8 (9 pathogens) and SF in 36 cases, respectively. In BC only the following pathogens were detected: S. epidermidis; b-haemolytic Streptococci (1); S. aureus (2); E. coli (1);E. coli and C. albicans (1); C. albicans (1); C. glabrata (1); C. parapsilosis (1); and BC-negative and SF-positive samples: S. epidermidis; b-haemolytic Streptococci (3); S. pneumoniae; S. spp. (6); S. aureus (3); E. faecalis (1); E. faecium (1); E. coli (6); K. pneumoniae/oxytoca (5); P. aeruginosa (5); C. albicans (4); C. tropicalis (1); A. fumigatus (1).

Conclusions: SF detected considerably more microorganisms than BC. The most striking differences were observed in S. pneumoniae, E. coli, Klebsiella, P. aeruginosa and C. albicans. In nine cases, however, BC yielded pathogens, which were not recovered by SF. In our study SF has been proven as a valuable tool for rapid diagnosis of septicaemia with a higher recovery rate than BC.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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