Illuminating the golden staph

A ground-breaking new technique developed by researchers at the Macquarie University node of the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), which is led by The University of Adelaide, will slash the time it takes to detect a golden staph infection, from two days to just two hours.

Golden staph (Staphylococcus aureus) lives on the skin and in the nose. It is usually harmless, but if it enters the skin through a cut it can cause a range of infections which, in some cases, are fatal.

In the most at-risk patients, it is vital to identify the infection and begin treatment with appropriate antibiotics as quickly as possible. However, current identification techniques involve culturing cells for up to two days to provide a positive infection result.

This innovative approach—known as Time-Gated Luminescent in Situ Hybridization (or LISH)—takes just two hours. The researchers are also working on Time-Gated luminescence immuno-detection techniques for rapid diagnosis of prostate cancer and various infectious diseases based on urine and blood samples.

LISH involves binding of a luminescent single-stranded DNA probe with a target nucleic acid within a cell. Often, biological samples such as tissue, blood and urine have their own fluorescence when viewed under microscopes, creating a kind of ‘background noise’. Using Time-Gated Luminescence (TGL) microscopy imaging eliminates this, making it far more sensitive in detecting any nucleic acid target than the conventional fluorescence in situ hybridisation (FISH) approach currently used.

	THE RESEARCHERS TARGETED THE BACTERIUM WITH A LUMINESCENT DNA PROBE, ALLOWING THEM TO FIND THE 'NEEDLE IN THE HAYSTACK' BECAUSE ONLY THE 'NEEDLE' LIGHTS UP.

 

Image: Labelled S. aureus cells illuminated under TGL microscopy (left bright field & right TGL microscopy). Credit: Macquarie University.