Biofilm-based Wound Management: Implications for Clinical Practice

Biofilm is a complex, often polymicrobial structure that can form on an array of surfaces, including teeth, implanted medical devices, showers and bathtubs, and notably chronic and hard-to-heal wounds.

For nonhealing wounds, planktonic bacteria—which are bacteria in their free-floating form—seed onto the surface of the wound and attach themselves to the wound base. They begin to form polymicrobial communities that can contain other species of bacteria and often fungal and viral components as well. These communities cover themselves with a protective coating called extra polymeric substance (EPS). The EPS is typically a polysaccharide. This sugary shell protects microbes within the biofilm from antibiotics and antimicrobials.1,2 This is why not all topical and systemic antibiotics and antiseptics will work on hard-to-heal wounds and why some may be chosen over others when designing biofilm-based wound management strategies. Within the EPS, polymicrobial communities communicate via a process known as quorum sensing. Quorum sensing allows communities to distribute resources, alert others, induce virulence, and even share antibiotic resistance genes, all within the protection of the EPS.3 While disrupting biofilm is an important component to any wound treatment strategy, biofilm is known to begin to form and reform in as little as 24 h.4,5 The speed at which biofilm forms and reforms means that these strategies are most effective when implemented into a protocol where evidenced-based antibiofilm interventions are used repetitively at each patient encounter.

Biofilm is known to be present in most, if not all, chronic and hard-to-heal wounds,4,6,7 but it is generally not visible to the naked eye. It is common for failed extracellular matrix, slough, exudate, and general wound debris to be mistaken for biofilm, even by experts in wound healing.2 Although the human eye typically cannot visualize biofilm, biofilm does tend to grow into these types of necrotic tissue. This is another reason why debridement is an important component of wound treatment: removing necrotic tissue lessens the overall bioburden and associated inflammation. Biofilms are known to be located on the surface of chronic wounds, but they also can integrate deeper into the tissue itself.2,8 Because of this, culturing a wound via swab may produce a false negative or only culture the planktonic bacteria, which would not provide clinically meaningful information.2

Managing biofilm has important implications on healing outcomes in chronic and hard-to-heal wounds as its presence is known to impact wound healing.2,4 Biofilm is considered the most important single cause of delayed wound healing after controlling for host factors associated with persistent, delayed healing, such as compression, offloading, debridement, and addressing any acute soft tissue infection.2 Wound care protocols that incorporate evidence-based wound bed preparation, control for host factors, and incorporate antibiofilm treatment strategies are known collectively as “wound hygiene.”4

Emerging evidence indicates that several interventions are associated with the disruption of biofilm in wounds. These technologies include noncontact, low-frequency ultrasonography, sharp debridement, and some dressings.2,4,6,9-11 Sharp debridement is considered one of the most important treatment strategies to combat biofilm and expedite wound healing.1,2,11 Once the EPS of biofilm is disrupted through a thorough sharp debridement, microbes within are exposed, and a window of time is opened where antimicrobials can be more effective.1,11 Continuing antibiofilm treatment after this initial disruption can help slow the reformation of biofilm and limit its negative effects on wound healing.

In conclusion, biofilm is known to present in most, if not all, chronic and hard-to-heal wounds. It usually cannot be seen by the naked eye, so its presence is presumed. Biofilm is associated with delayed wound healing, and incorporating evidence-based antibiofilm strategies into a proactive wound healing protocol of care that is delivered regularly and repetitively can expedite wound healing and improve patient outcomes.4,12

References

1. Wolcott RD, Rumbaugh KP, James G, et al. Biofilm maturity studies indicate sharp debridement opens a time-dependent therapeutic window. J Wound Care. 2010;19(8):320-328. doi:10.12968/jowc.2010.19.8.77709
2. Schultz G, Bjarnsholt T, James GA, et al. Consensus guidelines for the identification and treatment of biofilms in chronic nonhealing wounds. Wound Repair Regen. 2017;25(5):744-757. doi:10.1111/wrr.12590
3. Zhao X, Yu Z, Ding T. Quorum-sensing regulation of antimicrobial resistance in bacteria. Microorganisms. 2020;8(3):425. doi:10.3390/microorganisms8030425
4. Murphy C, Atkin L, Vega de Ceniga M, et al. Embedding wound hygiene into a proactive wound healing strategy. J Wound Care. 2022;31(Sup4a):S1-S19. doi:10.12968/jowc.2022.31.Sup4a.S1
5. Mancl KA, Kirsner RS, Ajdic D. Wound biofilms: lessons learned from oral biofilms. Wound Repair Regen. 2013;21(3):352-362. doi:10.1111/wrr.12034
6. 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
7. Johani K, Malone M, Jensen S, et al. Microscopy visualisation confirms multi-species biofilms are ubiquitous in diabetic foot ulcers. Int Wound J. 2017;14(6):1160-1169. doi:10.1111/iwj.12777
8. Schaber JA, Triffo WJ, Suh SJ, et al. Pseudomonas aeruginosa forms biofilms in acute infection independent of cell-to-cell signaling. Infect Immun. 2007;75(8):3715-3721. doi:10.1128/IAI.00586-07
9. Seth AK, Nguyen KT, Geringer MR, et al. Noncontact, low-frequency ultrasound as an effective therapy against Pseudomonas aeruginosa-infected biofilm wounds. Wound Repair Regen. 2013;21(2):266-274. doi:10.1111/wrr.12000
10. Phillips PL, Yang Q, Davis S, et al. Antimicrobial dressing efficacy against mature Pseudomonas aeruginosa biofilm on porcine skin explants. Int Wound J. 2015;12(4):469-483. doi:10.1111/iwj.12142
11. Malone M, Swanson T. Biofilm-based wound care: the importance of debridement in biofilm treatment strategies. Br J Community Nurs. 2017;22(Sup6):S20-S25. doi:10.12968/bjcn.2017.22.Sup6.S20
12. Rajpaul K. Biofilm in wound care. Br J Community Nurs. 2015;Suppl Wound Care:S6-S11. doi:10.12968/bjcn.2015.20.Sup3.S6