New point-of-care diagnostic testing could help doctors detect wound infection in less than a minute, according to a new study in Wound Repair and Regeneration. This new testing would present a vast improvement over the 24 hours it currently takes to plate and incubate bacteria.

Point-of-care diagnostic testing has progressed rapidly in many areas of clinical practice. These portable devices can now produce laboratory-quality immunoassays and other results in just minutes. Point-of-care diagnostic testing in the field of wound care has progressed more slowly, however, and there is still significant need for rapid alternatives for bacterial identification. Even the newest identification methods require several hours of incubation to get enough cells for analysis.

Researchers at George Washington University used wound fluid from chronic wound patients enrolled in the Wound Etiology – HEAL (WE-HEAL) Study. They used inexpensive, disposable electrochemical sensors to detect pyocyanin excreted by Pseudomonas aeruginosa, present in most chronic wounds.

The researchers compared the electrochemical results against 16S rRNA profiling using 454 pyrosequencing. Blind identification of the results yielded nine correct matches, two false negatives, and three false positives, resulting in a sensitivity of 71 percent and specificity of 57 percent for detection of Pseudomonas.

"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 Victoria Shanmugam, director of the Division of Rheumatology at the GW School of Medicine and Health Sciences and principal investigator of the WE-HEAL study. "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."

After further enhancements and testing, this method could some help doctors detect wounds at the bedside and even in the emergency department. This would allow ED physicians to switch to specific directed therapies sooner, rather than the current method of prescribing broad-spectrum antibiotics for the patient to use until the lab results become available.

Immediate diagnostics lowers healthcare costs, minimizes drug resistance and improves patient care outcomes. Furthermore, this approach requires only 7.5 microliters of sample, eliminates sample preparation and takes less than one minute to complete.

"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," Shanmugam said.

The research team plans ongoing enhancement and development of the approach with a goal creating a rapid point-of-care diagnostic tool for infection. They hope to make the tool capable of detecting other bacteria and optimize it for clinical use.