Simple Color Change Test Identifies Wound Infections

  • March 22, 2022

The test works by detecting virulence factors released by the bacteria, which prompt a simple color change in a solution.  The test could help clinicians to determine whether to prescribe antibiotics, and may help to avoid unnecessary prescribing.  As the test can be administered at the point of care, and does not require expensive and time-consuming laboratory analysis, it may be very useful in low-resource or remote regions.

At present, it can be difficult to know whether a wound is infected, especially at the very early stages of infection when prompt treatment could make a big difference.  Commonly, wound swab samples need to be analyzed in a lab, taking significant time, effort, and resources to identify infection.  By the time an infection is confirmed, the opportunity to tackle it early may have been missed.  To avoid this, clinicians may prescribe antibiotics prophylactically, or if an infection is merely suspected but not confirmed.

While this may be prudent, depending on the clinical situation, excessive prescribing and use of antibiotics underlies the emergence of multidrug-resistant bacteria, and so it is important that we only use these drugs when needed.  Ruling an infection in or out quickly would be very useful, and this new technology aims to provide a simple method to achieve this.  The new test, which the developers have called the SPaCE NtP swab sensor kit, has been developed and is being commercialized by a spin-out company called SmartWound Limited.

The test consists of swabbing a wound then inserting the swab into a special solution which changes color in the presence of bacteria that can be harmful in wounds:  Staphylococcus aureus, Pseudomonas aeruginosa, Candida species, and Enterococcus faecalis (SPaCE).

The test solution contains small vesicles that encase a fluorescent dye.  When a swab from a wound infected with one or more of the SPaCE bacteria is incubated in the solution, virulence factors released by these bacteria lyse the vesicles, releasing the dye, and the color change can easily be determined using a handheld fluorimeter.

Providing a result in just 30–60 minutes, the system could be ideally suited for low-resource and remote use.  “Antimicrobial Resistance (AMR) is seen as a major healthcare challenge by the World Health Organization (WHO),” said Toby Jenkins, a Researcher involved in the study, in a University of Bath announcement.  “Our technology will enable healthcare professionals to make better prescribing decisions, which will help reduce the spread of resistance.”

REFERENCE:  MedGadget; 05 NOV 2021; Conn Hastings

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