Autofluorescence imaging device for real-time detection and tracking of pathogenic bacteria in a mouse skin wound model: preclinical feasibility studies


Bacterial infection significantly impedes wound healing. Clinical diagnosis of wound infections is subjective and suboptimal, in part because bacteria are invisible to the naked eye during clinical examination. Moreover, bacterial infection can be present in asymptomatic patients, leading to missed opportunities for diagnosis and treatment. We developed a prototype handheld autofluorescence (AF) imaging device (Portable Real-time Optical Detection, Identification and Guidance for Intervention – PRODIGI) to noninvasively visualize and measure bacterial load in wounds in real-time. We conducted preclinical pilot studies in an established nude mouse skin wound model inoculated with bioluminescent Staphylococcus aureus bacteria. We tested the feasibility of longitudinal AF imaging for in vivo visualization of bacterial load in skin wounds, validated by bioluminescence imaging. We showed that bacteria (S. aureus), occult to standard examination, can be visualized in wounds using PRODIGI. We also detected quantitative changes in wound bacterial load over time based on the antibiotic treatment and the correlation of bacterial AF intensity with bacterial load. AF imaging of wounds offers a safe, noninvasive method for visualizing the presence, location, and extent of bacteria as well as measuring relative changes in bacterial load in wounds in real time.

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aUniversity Health Network, Princess Margaret Cancer Centre, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
bUniversity of Toronto, Department of Medical Biophysics, Faculty of Medicine, 1 King’s College Circle, Toronto, Ontario M5S 1A8, Canada.
cUniversity Health Network, Department of Biostatistics, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
dUniversity of Toronto, Dalla Lana School of Public Health, 155 College Street, 6th Floor, Toronto, Ontario M5T 3M7, Canada.
eUniversity Health Network, Techna Institute, 124-100 College Street, Toronto, Ontario M5G 1P5, Canada.