Can We Wound Biofilms?
These complex 3D structures of bacteria explain many of the challenges clinicians face with wound care, infection and healing. Scientists are fighting back.
Antonie van Leeuwenhoek (1632-1723) was the first person to delve into the field of microbiology and document initial observations of bacteria. After this preliminary discovery, microbiology was not actively studied again until the 1800s, when it began to gain a foothold in contemporary medicine. Fast-forward to today’s labs, where clinicians are becoming more knowledgeable in the bacteriology of wound healing, and researchers are identifying new ways to overcome long-standing challenges in wound healing, such as biofilms.
Biofilm is a term used to describe a colony of microorganisms, such as bacteria, fungi or yeast, encased by an extracellular polymeric substance (EPS). The EPS forms a shield, often causing the bacteria to be resistant to antibodies. While biofilms have been understood in nature for many decades, researchers are only recently beginning to recognize the role they play in infected wounds and the healing process.
The US National Institutes of Health (NIH) estimates that 80% of human bacterial infections involve biofilms. These infections can develop quickly, sometimes in a matter of hours, and are highly complex. Biofilms are resistant to the defense mechanisms of the body, and as polymicrobial systems, they are difficult to treat with systemic antibiotics or topical antibiotics.
Biofilms may explain many of the challenges clinicians face with wound care, infection and healing. Due to antibiotic resistance, biofilms may cause chronic infections or prevent wounds from fully healing because the infection is never fully eradicated. Persistent infection can lead to systemic infections, risky prolonged exposure to antibiotics or amputation of the infected site.
Tasked with breaking down biofilms in order to develop effective treatments, scientists are conducting in vivo studies to better understand biofilm properties and identify ways to expose the bacteria. Two models that our lab developed to study the effectiveness of treatments for infected wounds in small and large animals, include the:
- Infection Prevention Model, where treatment is applied prior to inoculation with bacteria and wounds are swabbed at regular intervals to determine bacteria levels.
- Infection Treatment Model, where treatment is delayed for several days to allow establishment of bacterial infection prior to treatment. Wounds are swabbed prior to treatment for baseline levels and then at regular intervals post-treatment to determine bacterial levels.
There are also models in development designed to test new treatments specifically for biofilms. The typical bacterial strain for all infected wound or biofilm models is methicillin-resistant Staphylococcus aureus or MRSA, as this environmental organism regularly causes infections in wounds and is a major concern in individuals with compromised immune systems, especially those who are hospitalized.
It’s evident that biofilms are a significant public health concern today and the more we do to understand their role in certain infectious disease and biofilm processes the greater the chances of controlling them and improving patient safety.
An earlier version of this post was published by MPI Research, which is now part of Charles River.