Comparison between Bactec Nr. 660 and a conventional 12-tube blood culture system.
The detection power of the automated blood culture system Bactec NR 660, based on infrared detection of carbon dioxide in an agitated aerobic medium and a non-agitated anaerobic medium, was compared with that of our conventional 12-tube blood culture system. Of 1685 paired blood cultures, 258 (15.3%) were positive in one or both systems. Clinically relevant isolates were found in 11.5%. The dominating species were Escherichia coli(41%), followed by Staphylococcus aureus(14%) and Klebsiella spp.(8%). The Bactec system detected 178 (10.6%) and the 12-tube system 157 (9.3%) clinically relevant microorganisms after seven days' incubation. Significantly more clinically relevant isolates were detected by the Bactec system alone as compared with the conventional system alone (40 versus 19, p less than 0.01). The detection time was significantly shorter in the Bactec system for all isolates and for E. coli and S. aureus separately (p less than 0.01). 1.8% of the isolates in the Bactec system and 2.1% in the 12-tube system were considered clinically non-relevant contaminants.
Department of Diagnostic Bacteriology and Antibiotics, Statens Seruminstitut, Copenhagen, Denmark.
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Nir
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Prag
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Jensen
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Arpi
D001322:Autoanalysis / Q000379:methods*; D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification; D001800:Blood Specimen Collection / Q000379:methods*; D006801:Humans; D018805:Sepsis / Q000097:blood / Q000175:diagnosis*