Validation of a Clinically Relevant Diagnostic Marker for Early Diagnosis of Infection in Chronic Wounds

INTRODUCTION: Bacteria contaminate and colonize chronic wounds, increasing the risk of systemic infection and amputation. Early detection of infection is vital for timely treatment. However, the current clinical practice of visually identifying signs and symptoms of infection is suboptimal and can significantly delay diagnosis and treatment. Bacterial proteases produced by pathogenic bacteria hold promise as an early biomarker of pathogenicity in chronic wounds. 

OBJECTIVE: In this study, the use of bacterial protease activity (BPA) was validated against clinical examination.

MATERIALS AND METHODS: A prospective multicenter study was carried at 7 wound clinics across the United States to analyze 366 chronic wounds, including venous leg ulcers, diabetic foot ulcers, and pressure ulcers. Signs and symptoms of the infection were assessed by the investigator using the nonerosive reflux disease (NERDS) criteria at time 0, week 4, and week 12. Along with the clinical assessment, 2 wound fluid swabs were collected for iCasein assay (protease activity) and quantitative microbiology. Wounds were classified as BPA positive if an iCasein activity threshold (125 mUnits/swab) was exceeded. Wound imaging, measurement, and documentation were captured using a laser-assisted wound measurement system.

RESULTS: Based on the NERDS criteria, a relatively small proportion (18%) exhibited 3 or more clinical signs of infection; however, 72% of the wounds had bacterial count > 105. About half of the wounds (49%) test positive for BPA. Interestingly, the median BPA in wound fluid was observed to increase when 2 or more signs of infection were present.

CONCLUSIONS: The findings provide strong evidence that bacterial proteases provide a clinically relevant diagnostic marker for early identification of infection in chronic wounds. Integrating a point of care BPA test in clinical practice will allow for early intervention and may help lower treatment cost associated with the care of chronic wounds.

CITATION
Serena T, Bayliff S, Brosnan P, Yaakov R. Validation of a clinically relevant diagnostic marker for early diagnosis of infection in chronic wounds. Poster presented at: Symposium on Advanced Wound Care Fall; November 2-4, 2018; Las Vegas, NV.

Product: Silhouette (Aranz Medical, Christchurch, New Zealand) 

This abstract was not subject to the WOUNDS peer-review process.