Electrochemical Test Rapidly Detects Infection in Wounds

A new study describes a method for testing bacteria in wounds that could lead to lower health care costs and improved patient outcomes.

Researchers at George Washington University (GW; Washington DC, USA), Northeastern University (Boston, MA, USA), and other institutions have developed an inexpensive, disposable electrochemical sensor that detects pyocyanin, a unique, redox-active molecule released by Pseudomonas aeruginosa in chronic wound fluids. By directly measuring the metabolite, the electrochemical test eliminates sample preparation, takes less than a minute to complete, and requires only 7.5 microliters of fluid to complete the analysis.

A study to compare the electrochemical results against rRNA profiling yielded nine correct matches, two false negatives, and three false positives, giving a sensitivity of 71% and a specificity of 57% for detection of P. aeruginosa. After further enhancement, the methodology could potentially provide a way to detect wound infections at the bedside, allowing physicians to switch from broad-spectrum antibiotics to specific directed therapies sooner, thus lowering health care costs, minimizing drug resistance, and improving patient care outcomes. The study was published on January 27, 2016, in Wound Repair and Regeneration.

“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 lead author Victoria Shanmugam, MD, director of the division of rheumatology at the GW School of Medicine and Health Sciences. “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.”

P. aeruginosa is a common Gram-negative bacterium that is recognized for its intrinsically advanced antibiotic resistance mechanisms and its association with serious illnesses, especially nosocomial infections such as ventilator-associated pneumonia (VAP) and sepsis syndromes. In all infections produced by P. aeruginosa, treatment is dually complicated by the organism's resistance profile, which may lead to treatment failure and expose patients to untoward adverse effects resulting from advanced antibiotic drug regimens.

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