How to Identify Biofilm in a Wound Protection Status
Staphylococcus aureus biofilm


One of my favorite topics to discuss in wound care is biofilms. When I conduct wound care in-services or trainings, I always ask the audience, "Who wants to tell me what a biofilm is?" There is silence. From that point, I proceed to tell my little story about biofilms. It sounds a little like this...You know when we go to bed at night, get up in the morning and feel that sticky film on our teeth? We brush our teeth with a minty-fresh toothpaste. Now our teeth feel clean. By the next morning, that sticky, fuzzy feeling returns, right? Or, when your pet's water dish develops that slimy swamp layer and then you change it? Well that, my folks, is a biofilm!

Think of those bright shiny red granulating wounds that become stagnant. We start throwing all sorts products on the wound, and nothing is working. Or maybe you see wound healing progress for a few weeks, and then it stalls again. My analogy might seem silly, but the health care professionals and patients that I educate remember it.

How to Identify a Biofilm

I think of biofilms as intelligent, diabolical creatures! When wound progress becomes stagnant for about 3-4 weeks, you should be suspicious of a biofilm colony. Many times biofilms are not seen. They are microscopic, but can present themselves as a shiny film. There are no signs and symptoms of infection. When the biofilm become larger, you can then identify them much easier. Biofilms are usually composed of mixed strains of bacteria, fungi, yeasts, algae, microbes, and other cellular debris. A biofilm is formed when certain types of microorganisms adhere themselves to the wound surface. A viscous substance is then secreted.

Why Biofilms Can Be a Challenge

Antibiotics are designed to attack bacteria, and may only partially eliminate the bacteria contained within a biofilm. The dense exopolymeric material (EPM) matrix actually paralyzes large antibodies and neutralizes microbicides. A biofilm is capable of promoting anaerobic bacteria growth, synergism between different bacteria, generating MRSA-resistant proteins, producing negative charges of polysaccharides and DNA bind cationic molecules like Ag+, antibiotics, and polyhexamethylene biguanide. This is why clinical studies show 60% of chronic wounds contain a biofilm, and can again reform in three days after sharp debridement. The wound appears to be healing, then becomes stagnant again.


The progressive development of biofilm.

Ways to Manage a Biofilm

Sequential sharp debridement of wounds will disrupt the biofilm growth and promote faster healing. Treating wounds with an antimicrobial or bacteriostatic dressing in an alginate or polymeric foam form will help prevent reformation of biofilms. Dressings impregnated with silver, cadexomer iodine, and methylene blue are at the top of the list. Stay away from gauze impregnated dressings and skin graft application, as this is the perfect food source environment for biofilms. Systemic antibiotics are used to destroy the biofilm microbes and prevent reseeding of bacteria on the wound surface. Maggot debridement therapy has been reintroduced for the treatment of chronic wounds. Studies have shown that the excretions/secretions of maggots contain many bioactive compounds.

"Biofilm has a 3D architecture and is like Facebook for bugs." -Mara Williams.

Harris LG, Bexfield A, Nigam Y, Rohde H, Ratcliffe NA, Mack D. Disruption of Staphylococcus epidermidis biofilms by medicinal maggot Lucilia sericata excretions/secretions. Int J Artif Organs. 2009 Sept;32(9):555-64.
Phillips PL, Yang Q, Davis S, et al. Antimicrobial dressing efficacy against mature Pseudomonas aeruginosa biofilm on porcine skin explants. Int Wound J. 2015 Aug;12(4):469-83. doi: 10.1111/iwj.12142
Stechmiller JK, Schultz G. Implementing Biofilm and Infection 2014 Guidelines. National Pressure Ulcer Advisory Panel. Available at
Wolcott RD, Rhoads DD. A study of biofilm-based wound management in subjects with critical limb ischemia. J Wound Care. 2008 Apr;17(4):145-8, 150-2, 154-5.

About the Author
Cheryl Carver is an independent wound educator and consultant. Carver's experience includes over a decade of hospital wound care and hyperbaric medicine. Carver single-handedly developed a comprehensive educational training manual for onboarding physicians and is the star of disease-specific educational video sessions accessible to employee providers and colleagues. Carver educates onboarding providers, in addition to bedside nurses in the numerous nursing homes across the country. Carver serves as a wound care certification committee member for the National Alliance of Wound Care and Ostomy, and is a board member of the Undersea Hyperbaric Medical Society Mid-West Chapter.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.

WoundSource ENEWS


I appreciate this very succinct, simple, but accurate explanation of biofilms. While some clinicians ignore biofilms, I have found that others are so concerned about biofilms that they are constantly disrupting the wound bed, which of course also damages new growth. As in all things on earth, balance is important.

Polymeric membrane dressings release a nontoxic surfactant to break the chemical bonds between the adherent microbial contamination and the wound bed. The glycerol in the dressings pulls fluid from the body into the wound bed, which floats the loosened contaminants so that they can easily be pulled into and onto the dressings by the locked-in superabsorbent, along with the excess watery portion of the fluid. The result is a continuously cleansed wound bed filled with concentrated nutrients from the body, and no need to disturb the fragile new granulation tissue - not even with rinsing at dressing changes!

Because of this powerful built-in wound cleansing system, new users must be warned to expect a dramatic increase in wound fluid during the first few days of polymeric membrane dressing use. Patients and families can easily be taught to change the dressings when the color of the outer membrane becomes darker, indicating that the dressing is saturated.

Linda Benskin, PhD, RN, SRN (Ghana), CWCN, CWS, DAPWCA
Clinical Research & Education Liaison, and Charity Liaison
Ferris Mfg. Corp. (and Independent Researcher for Developing Countries)

Very informative piece on biofilm. I have used maggots in management of biofilms and the results have been very impressive. After maggot debridement therapy, either use of foam dressing or grafting at the earliest opportunity ensures either no return of biofilm or there is complete healing. Maggot debridement therapy is the cheapest option, of course with the patient's acceptance.

Thank you for a concise overview, there are few who could explain biofilm so simply, however may I suggest that biofilm are capable of reforming in 24 hours not 3 days. In addition, plasmid mediated resistance is extremely common in a biofilm and is currently contributing significantly to multi drug resistant infections as a result. These must be taken seriously and addressed. Hypochlorous acid 0.046% (Anolyte) I've found to be the most effective cleaning solution for destroying all but the persisted cell. Anyone else using it?

Im beyond thrilled with the description of biofilm and some suggestions in tackling it. I deal with the worst of the worst chronic wounds in a hospice setting. I have had such terrific luck with the Anacapa line of products. Anasept irrigation solution, Anasept wound cleanser spray and finally my favorite all time product the Anasept gel. 0.54% sodium hypochlorite! It is compatible with silicone and foam based dressings! Heal on my friends!

Very nice piece about the biofilm. Indeed biofilms are really hard to cope with, and most promising methods often bring about irritations to the host tissue that do not promote or can even further impede the wound healing process. This said, I really would like to see antimicrobial Photodynamic Therapy become more known and accepted. Besides the broad-spectrum antimicrobial activity, also against biofilm-encapsulated pathogens, the application of Low-Level-Laser (painless, while no thermic effects) even has additional anagic, anti-inflammatory and pro-regeneritive effects to the wound. This form of therapy pre-dates the invention of antibiotics, but schould now be reconsidered. The cases-studies are encouraging. Lessons could be learned from dental medicine, where aPDT has been successfully applied for more than a decade in periodontitis (biofilm!) and dental surgery.

Hi Cheryl, nice article that properly identifies the importance of eradicating biofilm production in wound healing. I am soon to start a study on identifying what proteins that are created and blocked by biofilms and the reasons why competing bacterial groups combine to prevent the immune system from repairing the damage naturally. Liz is correct in stating that biofilms can aggressively reform in less than 48hrs and perhaps the solution will be to attack the issues from both ends and to properly analyze the slough for active ingredients.

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