A bioluminescent Pseudomonas aeruginosa wound model reveals increased mortality of type 1 diabetic mice to biofilm infection

OBJECTIVE: To examine how bacterial biofilms, as contributing factors in the delayed closure of chronic wounds in patients with diabetes, affect the healing process. METHOD: We used daily microscopic imaging and the IVIS Spectrum in vivo imaging system to monitor biofilm infections of bioluminescent Pseudomonas aeruginosa and evaluate healing in non-diabetic and streptozotocin-induced diabetic mice. RESULTS: Our studies determined that diabetes alone did not affect the rate of healing of full-depth murine back wounds compared with non-diabetic mice. The application of mature biofilms to the wounds significantly decreased the rate of healing compared with non-infected wounds for both non-diabetic as well as diabetic mice. Diabetic mice were also more severely affected by biofilms displaying elevated pus production, higher mortality rates and statistically significant increase in wound depth, granulation/fibrosis and biofilm presence. Introduction of a mutant Pseudomonas aeruginosa capable of producing high concentrations of cyclic di-GMP did not result in increased persistence in either diabetic or non-diabetic animals compared with the wild type strain. CONCLUSION: Understanding the interplay between diabetes and biofilms may lead to novel treatments and better clinical management of chronic wounds.