New point-of-care test rapidly detects Pseudomonas infection in wounds

An inexpensive, disposable, electrochemical sensor can detect Pseudomonas infection in chronic wounds in less than a minute with good sensitivity and specificity, researchers reported online January 27, 2016 in Wound Repair and Regeneration.

Because such a point-of-care test could be performed rapidly and its results used immediately (as opposed to several hours or up to a day required for current methods), this test has the potential to lower health care costs, minimize drug resistance, and improve patient outcomes, the researchers predicted.

“Being able to detect Pseudomonas and other infectious organisms at the time of the clinic visit will greatly enhance our ability to take care of patients,” said the study’s co-author Victoria Shanmugam, MD, Director of the Division of Rheumatology at the George Washington University School of Medicine and Health Sciences, in Washington, DC. “We would not have to wait for culture results before making a decision about antibiotics, and this would allow us to better tailor therapies for our patients.”

Dr. Shanmugam is also the principal investigator of the Wound Etiology and Healing (WE-HEAL) study, a National Institutes of Health-funded biospecimen and data repository designed for studying chronic wounds. Pseudomonas aeruginosa is known to delay healing in chronic wounds.

In the present study, Dr. Shanmugam and colleagues collected wound effluent specimens from a convenience sample of 12 participants from the WE-HEAL study. The researchers tested the samples with a disposable electrochemical sensor that detects pyocyanin, a unique toxic metabolite produced by Pseudomonas. The researchers compared the electrochemical results against the current gold standard of bacteria testing (16S rRNA profiling), and determined that the probe correctly identified the presence of Pseudomonas with a sensitivity of 71% and specificity of 57%.

The researchers aim to develop the probe as a rapid, point-of-care screening test for P. aeruginosa and other clinically-relevant bacteria, which would allow clinicians to promptly switch from broad-spectrum antibiotics to specific directed therapies, improving patient care outcomes.

“Infections are a major challenge in medicine, and by using this probe, we were able to harness one of the unique molecules produced by bacteria to detect infection,” Dr. Shanmugam said. “We plan to continue to refine this testing method and hope to scale it up for detection of other bacteria and to optimize it for clinical use.”