Researchers have discovered that fungi found in chronic wounds can form mixed bacterial-fungal biofilms associated with poor outcomes and longer healing times.

Their characterization of the fungi found in diabetic foot ulcers was published in the online Journal of the American Society for Microbiology.

Researchers in Pennsylvania and Iowa followed 100 patients with diabetic foot ulcers over 26 weeks, or until the wound healed or required amputation. They sampled patients’ deep wound fluid every two weeks, conducting genetic sequencing to identify 284 specific fungi.

Though no one species was associated with poor outcomes, mixed communities in which bacteria and fungi comingled were linked to slow healing or complications. Together, they can create biofilms, which are thought to keep many chronic wounds festering.

Understanding how those species interact has been a “huge missing piece” in  wound care, said senior author Elizabeth Grice, assistant professor at the University of Pennsylvania. 

More than 7 million American diabetics will have a diabetic foot ulcer in their lifetime. Fifteen percent will face lower limb amputation.