A Prospective Multi-site Observational Study Incorporating Bacterial Fluorescence Information into the UPPER/LOWER Infection Checklists

Introduction: The UPPER/LOWER infection checklists look for signs and symptoms of local/superficial infection (UPPER) and deep infection (LOWER) to assist clinicians in identifying and distinguishing between these infection levels, facilitating appropriate treat with topicals versus systemic antibiotics. This case series evaluated the utility of incorporating real-time information on high bacteria loads, via real-time bacterial fluorescence imaging into these checklists.

Methods: This was a prospective, multi-site observational study of 26 chronic wounds, including nine pressure ulcers (PUs). Patients were initially assessed with the checklists to look for signs or symptoms of local/superficial infection (UPPER) and deep infection (LOWER); three symptoms present from either checklist was the threshold for infection-positive. Fluorescence images of their wound were then acquired to look for regions of bacteria, which uniquely fluoresce red or cyan under the violet light of the imaging device.

Results: Fourteen wounds (54%), including 7/9 PUs, were considered infected based on UPPER/LOWER checklists. Fluorescence images were positive for bacterial presence in each of these wounds. In eight wounds (31%), including 2/9 PUs, adding bacterial fluorescence information brought the wound past the UPPER checklist threshold, greatly influencing treatment decisions. Culture results later confirmed fluorescence findings. In the remaining four wounds, three checks were not obtained even with fluorescence positive images. Two of these wounds exhibited bacterial (red) fluorescence that completely removed with cleaning or debridement; post-debridement swabs were negative, suggesting surface bacteria only, supporting the lack of UPPER/LOWER signs and symptoms.

Conclusion: These cases suggest that the UPPER/LOWER checklists and fluorescence images work in a complementary manner, with each providing additional, unique information not captured by the other. Therefore, incorporation of a bacteria-specific component into these infection checklists had high utility in pressure ulcers and other chronic wounds, identifying additional patients in need of topical antimicrobials, antibiotics, additional cleaning/debridement, and other bacterial targeted treatments.