Microbial communities that attach to tissue and secrete a protective matrix shape the biology of persistent wounds. Pioneering work by William Costerton, University of Calgary, established the concept that bacteria living in structured biofilms behave very differently from free-floating cells. Subsequent experimental and clinical studies by Philip S. Stewart, Center for Biofilm Engineering, Montana State University, and clinical investigations by Garth A. James, Drexel University, documented biofilm presence in chronic wounds and linked those communities to impaired healing.
How biofilms form and persist
Biofilms develop when microbes adhere to wound surfaces and produce an extracellular polymeric matrix that includes polysaccharides, proteins, and extracellular DNA. That matrix creates steep gradients of oxygen and nutrients, producing metabolic heterogeneity in which some cells are slow-growing or dormant and therefore tolerant to antibiotics. Biofilm cells communicate chemically through quorum sensing and express stress-response programs that reduce susceptibility to host defenses and antimicrobials. The combined effect is a physical and physiological barrier: antibodies and phagocytes are less effective at clearing organisms, and antibiotics that target actively dividing cells often fail. This persistence is not uniform; composition and resilience vary by wound type, treatment history, and patient physiology.
Clinical consequences and treatment barriers
Clinically, biofilm-associated wounds commonly show prolonged inflammation, delayed granulation and re-epithelialization, and recurrent infection after apparent improvement. Because biofilms are typically polymicrobial, interactions among species can amplify virulence and promote protease activity that degrades host extracellular matrix and growth factors. These pathophysiologic changes increase the likelihood of chronic ulceration, secondary complications such as osteomyelitis in diabetic foot wounds, and the need for repeated debridement or even amputation in severe cases. Standard systemic antibiotics and superficial wound cultures often underestimate or fail to eradicate the resident community, creating a mismatch between laboratory results and clinical outcomes.
Addressing biofilm-driven wounds requires integrated strategies: thorough mechanical debridement, topical agents with biofilm activity, optimization of circulation and glycemic control, and development of anti-biofilm therapeutics informed by basic research. Cultural and territorial factors that limit access to specialized wound care amplify the human and economic burden, underscoring the need for policy and education interventions alongside biomedical advances.