Bacterial Fluorescence Image Guidance of Antimicrobial Decision Making and Stewardship

Objective: Targeted, appropriate antimicrobials can prevent escalation to infection and future antibiotic necessity. Antimicrobial misuse often stems from diagnostic uncertainty during assessment for clinical signs and symptoms of infection (CSS). Rapid point-of-care fluorescence imaging, which visualizes bacteria at moderate/heavy loads in real-time, could alleviate uncertainty. Its ability to guide antimicrobial decision making was assessed as part of a multi-site clinical trial (NCT03540004).

Method: 166 chronic wounds (70 DFU/42 VLU/19 PU/26 SSI) were assessed for CSS based on IWII guidelines by 15 clinicians across 10 trial sites and treatment plan was recorded. Fluorescence images (FL) were then acquired, clinicians determined whether bacterial fluorescence was present (FL+), and treatment plan was modified if clinician deemed warranted. 

Results: The antimicrobial treatment plan was modified for 106/166 patients (64%) after seeing fluorescence images. 26% were switched to a more targeted topical antimicrobial product (e.g. silver based), 3% were given a lower level product (e.g. antimicrobial instead of antibiotic), and 35% were deemed to require higher antimicrobial treatment; mostly topical products when no antimicrobials had originally been prescribed. Antimicrobial changes occurred primarily, but not exclusively, in CSS-/FL+ patients (68% of group) and CSS+/FL+ patients (75% of group).

Conclusion: The data from this multi-site study of diverse wounds demonstrate the potential of real-time information on bacterial presence, obtained via bacterial fluorescence imaging, to guide evidence-based deployment of antimicrobials and antibiotics. Earlier identification of bacterial loads led to earlier and more targeted antimicrobial deployment. Evidence-based, timely intervention decreased the reliance on broad spectrum solutions, likely preventing escalation up the infection continuum and later antibiotic necessity.