Article Text

Download PDFPDF

Comparison of Bactec NR-660 and Signal systems.
  1. K Rimmer,
  2. M Cabot
  1. Department of Medical Microbiology, Royal Liverpool Hospital.


    Bactec NR-660, a computerised blood culture system using infrared analysis of microbial generated carbon dioxide, was compared with the Signal system, which detects gaseous pressure (due to bacterial metabolism) by a manometer. Four trials were undertaken: an in vitro evaluation of 99 bacteria in simulated blood cultures, and three prospective comparisons of a total of 2588 paired patient samples. Combined results for bacteria in simulated blood cultures showed a highly significant difference (p less than 0.001) between Bactec NR-660 aerobic medium (6A) and any other phial under test. Detection rates for most bacteria by Signal were on average three times slower than the first Bactec phial (mean delay 58.3 hours). Overall, the systems were not comparable.

    Statistics from

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.