Diagnostic accuracy of a fluorescence imaging device in diabetic wounds: a pilot study using a tissue culture system

DFUs are challenging chronic wounds that are vulnerable to infections. A fluorescence imaging device was developed to detect bacterial presence in wounds. This device utilizes the principle that when illuminated by violet light, some bacteria emit red fluorescence and others, such as Pseudomonas aeruginosa, emit cyan fluorescence. Several studies have reported the accuracy of this device. However, to the best of the authors' knowledge, no studies have examined the correlation between bacterial presence and tissue biopsy culture results in diabetic wounds. This study aimed to investigate the diagnostic accuracy of a fluorescence imaging device using a tissue culture system. Thirty-five patients (48 wounds) were included. Wounds were sampled using tissue culture methods and photographed using the fluorescence imaging device. Culture outcomes were categorized into non-Pseudomonas bacterial, Pseudomonas bacterial, both bacterial, and no-growth groups. Image outcomes were categorized into red, cyan, both colors, and negative groups. For detecting the presence of bacteria, the fluorescence imaging device showed a sensitivity, specificity, PPV, and NPV of 64.1%, 55.6%, 86.2%, and 26.3%, respectively, with an accuracy of 62.5%. For P aeruginosa, the device showed a sensitivity, specificity, PPV, and NPV of 66.7%, 87.2%, 54.6%, and 91.9%, respectively, with an accuracy of 83.3%. For non-Pseudomonas bacteria, the device showed a sensitivity, specificity, PPV, and NPV of 43.8%, 62.5%, 70.0%, and 35.7%, respectively, with an accuracy of 50.0%. The fluorescence imaging device can help to detect the bacterial bioburden; however, its accuracy may be lower than that reported in previous studies of diabetic wounds.