Use of a bacterial fluorescence imaging device: wound measurement, bacterial detection and targeted debridement.

OBJECTIVE: Diagnostics which provide objective information to facilitate evidence-based treatment decisions could improve the chance of wound healing. Accurate wound measurements, objective bacterial assessment, and the regular, consistent tracking of these parameters are important aspects of wound care. This study aimed to assess the accuracy, clinical incorporation and documentation capabilities of a handheld bacterial fluorescence imaging device (MolecuLight i:X). METHOD: Benchtop wound models with known dimensions and clinical wound images were repeatedly measured by trained clinicians to quantify accuracy and intra/inter-user coefficients of variation (COV) of the imaging device measurement software. In a clinical trial of 50 wounds, wound dimensions were digitally measured and fluorescence images were acquired to assess for the presence of bacteria at moderate-to-heavy loads. Finally, fluorescence imaging was implemented into the routine assessment of 22 routine diabetic foot ulcers (DFU) to determine appropriate debridement level and location based on bacterial fluorescence signals. RESULTS: Wound measurement accuracy was >95% (COV <3%). In the clinical trial of 50 wounds, 72% of study wounds demonstrated positive bacterial fluorescence signals. Levine sampling of wounds was found to under-report bacterial loads relative to fluorescence-guided curettage samples. Furthermore, fluorescence documentation of bacterial presence and location(s) resulted in more aggressive, fluorescence-targeted debridement in 17/20 DFUs after standard of care debridement failed to eliminate bacterial fluorescence in 100% of DFU debridements. CONCLUSION: The bacterial fluorescence imaging device can be readily implemented for objective, evidenced-based wound assessment and documentation at the bedside. Bedside localisation of regions with moderate-to-heavy bacterial loads facilitated improved sampling, debridement targeting and improved wound bed preparation.

Improved detection of clinically relevant wound bacteria using autofluorescence image-guided sampling in diabetic foot ulcers.

Clinical wound assessment involves microbiological swabbing of wounds to identify and quantify bacterial species, and to determine microbial susceptibility to antibiotics. The Levine swabbing technique may be suboptimal because it samples only the wound bed, missing other diagnostically relevant areas of the wound, which may contain clinically significant bacteria. Thus, there is a clinical need to improve the reliability of microbiological wound sampling. To address this, a handheld portable autofluorescence (AF) imaging device that detects bacteria in real time, without contrast agents, was developed. Here, we report the results of a clinical study evaluating the use of real-time AF imaging to visualise bacteria in and around the wound bed and to guide swabbing during the clinical assessment of diabetic foot ulcers, compared with the Levine technique. We investigated 33 diabetic foot ulcers (n = 31 patients) and found that AF imaging more accurately identified the presence of moderate and/or heavy bacterial load compared with the Levine technique (accuracy 78% versus 52%, P = 0·048; adjusted diagnostic odds ratio 7·67, P < 0·00022 versus 3·07, P = 0·066) and maximised the effectiveness of bacterial load sampling, with no significant impact on clinical workflow. AF imaging may help clinicians better identify the wound areas with clinically significant bacteria, and maximise sampling of treatment-relevant pathogens.

Handheld fluorescence imaging device detects subclinical wound infection in an asymptomatic patient with chronic diabetic foot ulcer: a case report.

Chronic wounds are a significant burden to global patient and health care infrastructures, and there is a need for better methods of early wound diagnosis and treatment. Traditional diagnosis of chronic wound infection by pathogenic bacteria, using clinical signs and symptoms, is based on visual inspection under white light and microbiological sampling (e.g. swabbing and/or biopsy) of the wound, which are subjective and suboptimal. Diagnosing microbial infection based on traditional clinical signs and symptoms in wounds of asymptomatic patients is especially challenging at the bedside. Bacteria are invisible to the unaided eye and wound sampling for diagnostic testing can cause unacceptable delays in diagnosis and treatment. To address this problem, we developed a new prototype handheld, portable fluorescence imaging device that enables non-contact, real-time, high-resolution visualisation of pathogenic bacteria and tissues in wounds. Herein, we report the clinical use of this imaging device in detecting subsurface heavy bacterial load and subclinical local infection in an asymptomatic 50-year-old patient with a non-healing diabetic foot ulcer.