Detection of bacteria in burn wounds with a novel handheld autofluorescence wound imaging device: A pilot study

Objective: To compare the detection of bacteria in burn wounds between an bacterial fluorescence imaging device MolecuLight i:X, (Canada), and standard microbiological swabs. Methods: Wounds were swabbed three times on one occasion; once with a standard swab, once with a high-fluorescent area swab, indicating a bacterial load >104 colony-forming units (CFU)/ gram and a finally with a non-fluorescent (nF) area swab. Proportion agreement of the microbiological results was calculated and the accuracy of the device to detect relevant bacteria was assessed. Results: A total of 14 patients with 20 wounds participated in the study. Median post-burn day at sampling time was 21 days. Of the 20 wounds, nine had a positive swab result in either of the three swabs, and 11 showed a highfluorescent area. Overall, positive and negative proportion agreement between standard swab and highfluorescent swab sample results were 100%. Sensitivity, specificity, positive and negative predictive values of presence of highfluorescence were 78%, 64%, 64%, and 78%, respectively. For Pseudomonas aeruginosa detection, these results were 100%, 70%, 44% and 100%, respectively. Conclusion: The diagnostic accuracy of the bacterial fluorescence imaging device to detect relevant bacteria in burn wounds was moderate and the reliability was equal to standard swabbing. Further research in larger sample sizes and on the relevance of minimal bacterial load and its potential to help with Pseudomonas aeruginosa management is needed. Declaration of interest: The authors have no conflicts of interests to declare. The authors gratefully acknowledge the contribution of MolecuLight Inc. and Jamie Joint; this included the use a MolecuLight device for two months at no charge.