A Bio on Biofilm

When bacteria, fungi, and other microorganisms are introduced into a wound as a result of contact between the wound and a contaminated source, the microorganisms can begin to take residence. The individual bacterial cells inhabiting the wound begin to produce and release substances that, with time, meld together and collectively create a biofilm.¹ Sometimes, these changes develop a more rapid and recognizable pathway that can be identified by the cardinal signs of infection, detected by wound cultures, and subsequently treated to resolve the problem. All too often, this is not the case.

Once established, a biofilm is generally very difficult to eradicate, and the reasons for this are multifaceted. The structural makeup of a biofilm allows for bacteria to hide within as well as for the biofilm to be shared among an array of other bacteria and microbes; this makes it challenging for culture methods to isolate the correct bacteria.^1–3 Additionally, the bacteria have an ability communicate and share genetic material, including resistance, among the biofilm colony.¹ These characteristics contribute to their tolerance to the host’s immune defenses and make them particularly recalcitrant to antibiotic therapy.^4–6

It is estimated that 78% of all chronic wounds have biofilm, with many speculating the prevalence can be as high as 100%.⁷ Biofilm is not specific to any classification and has been found in all chronic wound etiologies.² The presence of biofilm causes inflammatory cells to migrate to the wound and begin to release substances that can inadvertently destroy normal tissue, proteins, and immune cells needed for healing.⁸ This causes the wound to stall and remain in the inflammatory phase instead of transitioning along the healing cascade to the proliferative phase.⁸

At this time, there are no definitive clinical indicators that can accurately prove the presence of biofilm within a given wound. As a result, the wound care specialist should assume the presence of biofilm and initiate biofilm-based wound management on all chronic wounds but especially those with:

• The presence of devitalized tissue,
• More than expected exudate,
• Negative wound cultures,
• Wounds that are unresponsive to antibiotics or antiseptics, and
• Wounds that are unresponsive to standard of care.^2,3

As with all wounds, it is imperative to identify and eliminate causative factors associated with the patient’s wound. Additionally, current biofilm-based best practice recommendations include:

• Aggressive debridement of non-vital tissue,
• Utilization of DNA molecular identification over traditional culture methods using actual tissue samples over surface specimens,
• Implementation of topical antiseptics and systemic antibiotics,
• Application of appropriate debriding agents/dressings, and
• Follow-up and reevaluation.^2,3

For example, a 64-year-old woman, who used a wheelchair and was obese, was a resident of long-term care. The patient had chronic venous stasis ulcers, lymphedema, and fairly managed type 2 diabetes, but there was no significant arterial disease. The patient had been seen at wound care clinics and lymphedema clinics and was also managed closely by her primary care physician group, which was certified in ostomy/wound care. Despite many of the components of standards of care, the wounds continued to deteriorate. The patient was discharged from the lymphedema clinic with prescribed lymphedema pumps, tubigrips, and farrowing wraps, which she wore daily. She received daily dressing changes of topical gentamycin, collagenase, and alginate with abdominal pads and bulky gauze roll performed by the nursing staff at the long-term care facility in which she resided.

Initially, the patient was hesitant to accept changes in treatment therapy due to the many years of failure that had beat down her optimism (hope). After a few visits and overcoming the initial hesitation, aggressive debridement was initiated, bacteria molecular testing was utilized and followed by antibiotics, and the use of hypochlorous acid-based wound cleanser was initiated. Furthermore, topical gentamycin was discontinued, while the rest of the dressings, compression, and patient habits/lifestyle remained the same as described previously.

Biofilm was a detriment to the patient’s wounds. The patient’s wounds improved as a result of utilizing the strategies of biofilm-based wound care.

References

1. Ereshefky M, Pedroso M. Rethinking evolutionary individuality. Proc Natl Acad Sci U S A. 2015;112(33):10126–10132. doi:10.1073/pnas.1421377112
2. Snyder RJ, Bohn G, Hanft J, et al. Wound biofilm: current perspectives and strategies on biofilm disruption and treatments. Wounds. 2017;29(6):S1–S17.   
3. Schultz G, Bjarnsholt T, James GA, et al. Consensus guidelines for the identification and treatment of biofilms in chronic nonhealing wounds. Wound Rep Reg. 2017;25:744–757. doi:10.1111/wrr.12590
4. Leid JG, Willson CJ, Shirtliff ME, Hassett DJ, Parsek MR, Jeffers AK. The exopolysaccharide alginate protects Pseudomonas aeruginosa biofilm bacteria from IFN-γ-mediated macrophage killing. J Immunol. 2005;175(11):7512–7518. doi:10.4049/jimmunol.175.11.7512
5. Gilbert P, Maira-Litran T, McBain AJ, Rickard AH, Whyte FW. The physiology and collective recalcitrance of microbial biofilm communities. ADV MICROB PHYSIOL. 2001;46:202–256. https://europepmc.org/article/med/12073654
6. Stewart PS, Costerton JW. Antibiotic resistance of bacteria in biofilms. Lancet. 2001;358(9276):135–138. doi:10.1016/s0140-6736(01)05321-1
7. Malone M, Bjarnsholt T, McBain AJ, et al. The prevalence of biofilms in chronic wounds: a systematic review and meta-analysis of published data. J Wound Care. 2017;26(1):20–25. doi:10.12968/jowc.2017.26.1.20    
8. Stacey M. Combined topical growth factor and protease inhibitor in chronic wound healing: protocol for a randomized controlled proof-of-concept study. JMIR Res Protoc. 2018;7(4):e97. doi:10.2196/resprot.8327

Seth Snowden is an Advanced Wound Specialist working with Wound Care Plus, LLC in the Greater Springfield, Missouri area.  As a part of the Wound Care Plus team, he was the first wound care specialist to apply a total contact cast in the long-term care setting.  Seth has almost fifteen years of diverse nursing experience and brings that wealth of knowledge to each individual he sees. He understands how chronic wounds can be a thief of joy, energy, time, comfort, and money, therefore, he is passionate about being able to assist or guide people through the resolution and lifting of that burden. Seth loves that each week through measurements, pictures, and response of the client, it is possible to see mountains moved or perhaps caverns be filled, and how amazing it feels to be a part of that process.