Use of a Fluorescence Imaging Device to Detect Elevated Bacterial Loads, Enhance Antimicrobial Stewardship, and Increase Communication Across Inpatient Complex Wound Care Teams

Tracey DasGupta, RN, MN; Laura Rashleigh, RN, BScN, MScN, CON(C); Kevin Zhou, MClSc-WH, BScN; Liz Williamson, RN, MN, CRN(C); Susan Schneider, RN, MN; Sukaina Muhammad, RN, MClSc-WH; Manry Xu, RN, MClSc-WH, BScN, BSc, NSWOC; Stephanie Chadwick, MClSc-WH, NP-PHC, BScN, NSWOC(C); Kathryn Rego, BScN, RN; Marc Jeschke, MD, PhD, FACS, FCAHS, FCCM, FRCS(C); Shahriar Shahrokhi, MD, FRCSC, FACS; Leslie Lam, CPA, MBA; Leda Sitartchouk, MSc; Lisa Di Prospero, BSc, MSc, MRT(T)


Wounds. 2022;34(8):201-208. 

In This Article

Abstract and Introduction


Introduction: Wounds are increasing in number and complexity within the hospital inpatient system, and coordinated and dedicated wound care along with the use of emerging technologies can result in improved patient outcomes.

Objective:This prospective implementation study at 2 hospital inpatient sites examines the effect of bedside fluorescence imaging of wounds in the detection of elevated bacterial loads and its location in/around the wound on the inpatient wound population.

Materials and Methods: Clinical assessment and fluorescence imaging assessments were performed on 26 wounds in 21 patients. Treatment plans were recorded after the clinical assessment and again after fluorescence imaging, and any alterations made to the treatment plans after imaging were noted.

Results: Prior to fluorescence imaging, antimicrobial use in this patient population was common. An antimicrobial dressing, a topical antibiotic, or an oral antibiotic was prescribed in 23 wounds (88% of assessments), with antimicrobial dressings prescribed 73% of the time. Based on clinical assessment, more than half of the treated wounds were deemed negative for suspected infection. In 12 of 26 wounds, the fluorescence imaging information on bacterial presence had the potential to prompt a change in whether an antimicrobial dressing was prescribed. Five of these 12 wounds were fluorescence imaging-positive and an antimicrobial drug was not prescribed, whereas 7 of the 12 wounds were negative upon fluorescence imaging and clinical assessment but antimicrobial dressing was prescribed. Overall, fluorescence imaging detected 70% more wounds, with bacterial fluorescence indicating elevated bacterial loads, compared with clinical assessment alone, and use of imaging resulted in altered treatment plans in 35% of cases.

Conclusions: Fluorescence imaging can aid in antimicrobial stewardship goals by supporting evidence-based decision-making at the point of care. In addition, use of such imaging resulted in increased communication, enhanced efficiency, and improved continuity of care between wound care providers and hospital sites.


Wounds are a so-called silent epidemic affecting patients both inside and outside of the hospital setting. A point prevalence study of wound audits in 13 Canadian hospitals in 2006 and 2007 reported that an average of 41.2% of hospitalized patients had wounds.[1] The increasing number and complexity of wounds within the hospital system results in both a financial and resource burden, with wound care accounting for 2% to 3% of total health care spending worldwide.[2,3] Because wound care is not limited to a single department, hospital systems are increasingly utilizing specialized, interprofessional wound care teams to optimize the care of acute and chronic wounds. These teams often perform resource-intensive care comprising comprehensive wound assessments and facilitate interventions by recommending the best treatment and care plan. Even with this dedicated staffing, wound care continues to place a significant strain on hospitals.

Appropriate detection and management of bacterial burden are critical to improving wound healing and preventing further serious infection or escalation of sepsis. Although all wounds contain some level of bacteria, studies have shown that bacterial loads exceeding 10[4] CFU/g contribute to delayed healing[4,5] and potentially increase the cost of caring for these wounds.[2,6] The concept of the infection continuum published by the International Wound Infection Institute provides context on the effect of bacteria on wounds and wound healing as wounds increase in number and virulence.[7] Low bacteria levels represent stages of contamination or colonization that should not delay healing and typically do not require antimicrobial agents. However, the bacterial burden reaches a tipping point, or level of critical colonization, at which point the number of bacteria and their virulence begin to stall wound healing and initiate a host response.[7] This point is reached between 104 CFU/g and 105 CFU/g of bacteria.[4,8] Past this tipping point, an infection can occur. Local infection can occur as the bacteria move deeper into the wound and increase in number.[7] A local infection presents with subtle signs, and early detection and intervention are essential to help prevent further escalation. Left undetected or untreated, this local infection can escalate to spreading and systemic infection as bacteria begin to invade the surrounding tissue and more overt signs of infection present, eventually resulting in serious complications.

Clinical signs and symptoms (CSS) of infection such as redness, swelling, pain, and odor are subjective and can be mistaken for inflammation, making it difficult to identify elevated bacterial loads that may cause infection.[9–11] Furthermore, these CSS may be suppressed or absent in immunocompromised individuals and patients with comorbidities.[12,13] Because of the lack of point-of-care information to aid in the wound assessment, treatment decisions are routinely made without sufficient information about wound bacterial burden. The microbiologic analysis of wound samples may take 2 to 3 days to acquire, thus contributing to treatment delays or forcing a prophylactic approach. This can lead to overprescribing antimicrobial agents or antibiotics "just in case," which may result in antimicrobial resistance.

Antimicrobial resistance is a major threat because it can produce clinical unresponsiveness to treatment and rapid evolution to sepsis and septic shock.[14] Antimicrobial stewardship programs can successfully reduce the use of antimicrobial agents without negatively affecting clinical outcomes in acute care settings.[15] In line with this goal and others, many countries have engaged with the Choosing Wisely campaign, with many hospitals adopting the Choosing Wisely recommendations.[16] This program aims to reduce unnecessary tests and treatments in health care, emphasizing evidence-based patient care. Choosing Wisely highlights several reasons why unnecessary tests or treatments may occur, including ingrained practice habits, outdated decision support systems, patient insistence, and defensive medicine practices. All of these reasons can be applied to decisions around antimicrobial and antibiotic use. A goal of this campaign and the current study is to promote the judicious use of antimicrobial agents or antibiotics with evidence-based prescribing. However, the challenge of how best to implement this evidence-based prescribing remains.

Fluorescence imaging has emerged as a diagnostic tool to aid clinicians in determining the presence of elevated levels of bacterial burden (>104 CFU/g) in acute and chronic wounds. Point-of-care fluorescence imaging has been researched extensively to validate its diagnostic accuracy and utility for bacterial detection and treatment planning.[11,17–19] Multiple clinical trials have demonstrated that fluorescence imaging has a positive predictive value of greater than 95% for detecting bacteria at loads greater than 104 CFU/g[11,17–20] and that it increases the sensitivity of detecting these bacterial loads by threefold to fourfold compared with assessment based on CSS alone.[11,17] The point-of-care fluorescence imaging device studied herein (MolecuLight i:X; MolecuLight Corp.) provides objective, diagnostic information that has been shown to alter treatment plans in approximately 70% of wounds,[11,17] including treatment decisions specifically concerning antimicrobial stewardship.[11,17,18]

Both early detection of bacteria and dedicated patient care are essential to improve wound healing rates. Sunnybrook Health Sciences Center, Toronto, Canada, instituted a wound care program that consists of a practice structure including unit-based advanced practice nurses, clinical educators, wound champions, and the Complex Wound Services (CWS) team to support care for wounds with high complexity. The CWS is a specialized team that includes 3 advanced practice nurses and 1 registered nurse who specialize in managing wounds. The vision is to provide excellent, state-of-the-art care for patients with complex wounds. Specialty trained nurses with NSWOC (nurse specialized in wound, ostomy, and continence) certification, working in partnership with unit-based teams, engage in complex consultations, independent follow-up, patient and family education, adjunct therapy, transition planning, and capacity building of local leaders and teams. The Wound, Ostomy, and Continence Steering Committee at Sunnybrook led best-practice implementation and evaluation. This structure develops and maintains best-practice policies, guidelines, and procedures that promote wound, ostomy, and continence management, providing leadership and oversight to enhance overall skin health and monitor outcome measures.

This study describes the implementation of a fluorescence imaging device at 2 Sunnybrook locations to aid the CWS team and unit-based advanced practice nurses. The purpose of this study was to determine if fluorescence imaging could detect more wounds with elevated bacterial loads compared with CSS alone, provide objective information to support evidence-based treatment decisions, and help facilitate increased communication between sites for improved continuation of care. Because the device has been thoroughly researched,[11,17–20] the aim of this study was not to revalidate its bacterial detection capabilities but instead to determine how that information could inform treatment decisions. The objective of the evaluation was to measure how often fluorescence imaging affected or changed the care plan, in particular in response to the selection of antimicrobial agents.