Rapid Pathogen ID in Blood Cultures / User Report

  • User: Dr Ian K Hosein & Josephine Silles
  • Establishment: The North Middlesex University Hospital
  • Date: December 23, 2013

Dr Ian K Hosein MD MA FCAP FRCPath MBA** Director of Infection Prevention & Control (pictured) and Josephine Silles, Microbiology Laboratory Manager, at The North Middlesex University Hospital,describe their experience using PNA FISH , the precursor to the new AdvanDx QuickFISH kits that are now available from Alpha Laboratories.

We have been trialling the AdvanDx PNA FISH® method for rapid identification of gram–positive cocci in clusters in positive blood cultures, for approximately one year. During that time we have obtained a statistically significant comparative in-vitro database that confirms its effectiveness for use in the routine clinical microbiology laboratory.

Use of PNA FISH has enabled us to distinguish coagulase-negative staphylococci from S.aureus within 90 minutes of a positive blood culture being signalled by our Bactec® system. This information is then used in
consulting with ward-based clinical staff. The methodology is based on Peptide Nucleic Acid (PNA) probes with unique hybridization characterisation and is presented in a convenient kit format, enabling samples to be examined in both batch or one-off mode.

Our experience has confirmed manufacturer views that the process is simple to perform with essentially 4 stages: prepare a smear using pre-formatted slides, hybridize, wash and examine under fluorescence microscopy. Importantly, the amount of hands-on time is comparatively low, estimated at 10 minutes per sample.

Our underlying objective was the introduction of useful technology into routine laboratory practice* and we now have a number of staff who have been trained to use the technique. They have found that it is both easy to implement in laboratory workflow and effective as a diagnostic tool. We are looking forward to the introduction of the new QuickFISH kits with the expected even greater speed and simplicity. In our hands, there is already increasing evidence that early pathogen identification, using the PNA FISH process for rapid identification of gram-positive cocci seen in positive blood cultures, has led to improved clinical outcomes and earlier patient discharges.

Alpha Laboratories is the exclusive UK distributor for AdvanDx QuickFISH kits that are
now available for Staphylococcus, Enterococcus and Gram Negative species identification. QuickFISH tests
require only 5 minutes hands on time and results are obtained within just 20 minutes.

References

*Hosein I, Duerden B I. Introducing rapid methods in the diagnostic laboratory. Reviews in Medical Microbiology 1994; 5:39-46.
**Note: Dr Hosein is now DIPC at Barking, Havering & Redbridge Hospitals NHS Trust

Note: This article was originally published in Leading Edge: Spring 2013.  If  you’d like to read similar news and articles, please visit: www.alphalabs.co.uk/leading-edge

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