Bacterial Fluorescence in the Application of Cellular Tissue Products

Introduction: Cellular and tissue-based products (CTPs) are applied to improve wound closure in non-healing wounds. Certain CTPs provide a biological scaffold to facilitate re-epithelialization, while others provide growth factors or cytokines to stimulate natural healing processes. Factors that can impede CTP integration include shearing and excessive tension, hematomas and seromas, poor vascularity and oxygenation, and infection. The presence of bacteria above a certain threshold can prevent CTP success, independent of overt infection. The presence/absence of autofluorescence signals indicating bacterial burden above 104 CFU/g have been associated with skin graft and healing outcomes after CTP application.1-3Methods:This prospective observational case series explores the association of bacterial fluorescence signals with venous and diabetic ulcer outcomes following CTP therapy. Patients were followed from their initial CTP application and on follow-up visits at weeks 2 and 4. Prior to CTP application, an independent researcher determined and recorded the bacterial presence in and around the wound bed using a non-contact, bedside bacterial fluorescence imaging device* . Early CTP integration was assessed at the 2-week mark (granulation tissue, epithelialization), and wound area reduction was assessed at 4-weeks, along with re-imaging to determine any changes in the wounds’ bacterial status. The clinical team were blinded to the imaging results and these results did not bias or influence any of the therapeutic decisions.Results:Bacterial fluorescence was evidenced frequently in the wound bed, particularly along the wound edges, in venous and diabetic ulcers even after routine wound bed preparation and immediately before CTP application. After 2 weeks, regional overlap was evidenced between areas free of bacterial fluorescence and new granulation/epithelialization. A greater than 40% percent area reduction (PAR) after 4 weeks was rarely observed when CTPs were applied over wounds positive for bacterial fluorescence. Fluorescence-negative wounds tended to achieve greater 4-week PAR.Discussion: The presence of moderate-heavy bacterial colonization, determined by bacterial fluorescence imaging, seemed to correlate with poor 4-week healing outcomes following CTP application as compared to fluorescence-negative wounds. These findings suggest that bacterial fluorescence imaging could improve CTP outcomes by enhancing wound bed preparation protocols and facilitating targeted removal of bacterial loads that reduce CTP efficacy.References:Isfahani, P., Alirezaei, S., Samani, S., Bolagh, F., Heydari, A., Sarani, M., & Afshari, M. (2024). Prevalence of hospital-acquired pressure injuries in intensive care units of the Eastern Mediterranean region: a systematic review and meta-analysis. Patient Safety in Surgery, 18(1). https://doi.org/10.1186/s13037-023-00383-8"