(CR-032) Does bacterial fluorescence imaging improve chronic wound biofilm detection over standard clinical assessment and blotting?

Liis Teene, MSc – Sr Director Clinical Affairs, MolecuLight; Perry Mayer, MB, BCh, FFPM RCPS – Medical Director, The Mayer Institute; Hanna Varonina, MSc – MolecuLight; Ashley Jacob, BSN – MolecuLight; Phil Bowler, PhD – Phil Bowler Consulting

Introduction: Biofilm, a more destructive and resilient form of bacterial loads, is highly prevalent in chronic wounds and must be mechanically removed to reinstate the healing cascade and avoid complications. Yet, biofilm is notoriously hard to identify and localize at the bedside, resulting in missed or incomplete removal and its rapid reconstruction within 24-hours. This study evaluated promising methods for point-of-care biofilm localization: fluorescence imaging of wound bacterial loads and biofilm blotting techniques.

Methods:

In this clinical trial, 40 chronic wounds (34 DFU, 3 VLU, 1 ALU, 1 neuropathic foot ulcer, 1 PU) underwent the following assessments: (1) Biofilm Based Wound Care (BBWC) checklist for clinical signs of biofilm¹, (2) blotting with a biofilm blotting technique, (3) fluorescence imaging for localizing bacterial loads*, wound scraping taken for (4) scanning electron microscopy to confirm matrix encased bacteria (biofilm), and (5) PCR and NGS sequencing to determine absolute bacterial load and species present.

Results:

20 patients with clinical indicators of biofilm, and 20 patients without clinical indicators of biofilm per BBWC checklist¹ were recruited. Among the entire cohort, 83% of wounds were microbiology positive for bacterial loads (qPCR). Blotting paper technique fared poorly in detection, with only 29% of wounds having positive blots. In contrast, fluorescence imaging detected regions of bacterial load, potentially biofilm, in 70% of wounds with bacteria (confirmed with qPCR/NGS sequencing). SEM images showing co-localization of bacterial loads and EPS matrix were used to confirm the presence of biofilm, which was strongly correlated with positive fluorescence (bacterial) imaging signals.

Discussion: Point-of-care methods which alert to and map out biofilm regions are revolutionary and clinically important in the management of chronic, stagnant wounds. By enabling the detection of regions of biofilm and high, pathogenic bacterial loads in and around wounds, treatments become targeted and potentially proactive. This study found that fluorescence imaging was able to alert to regions of biofilm in the clinical setting. Our data indicate that this safe, non-invasive, point-of-care optical imaging technology, which requires no contrast or contact with the patient, offers a unique and rapid approach to detecting wound biofilm to encourage optimal wound hygiene and clinical outcomes.

Trademarked Items: MolecuLight

References: 1Wolcott, Wounds Middle East, 2014