Biofilms Role in Chronic Infections
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A biofilm is an architectural colony of microorganisms, within a matrix of extracellular polymeric substance that they produce. Biofilm contains microbial cells adherent to one-another and to a static surface (living or non-living). Bacterial biofilms are usually pathogenic in nature and can cause hospital infections. The National Institutes of Health (NIH) revealed that among all microbial and chronic infections, 65% and 80%, respectively, are associated with biofilm formation.
The image shows a colony of biofilm.
A common misconception of microbial life is that bacteria exist as individual organisms in a ‘planktonic state’. However microorganisms have been shown to naturally accumulate on a wide variety of surfaces; where they form sessile, sedentary communities. Those surfaces include biomaterials such as contact lenses, medical devices including implants and urinary catheters. Bacterial contamination on implants and prosthetic medical devices causing infections can be life-threatening, leading to device failure, chronic infections and high mortality and morbidity rates.
Infections associated with Biofilm
It is estimated that about 65% of all bacterial infections are associated with bacterial biofilms. These include both, device- and non-device-associated infections. These include:
- Device related infections (device related infections affecting 2% of joint replacements, 4% for heart valves, 10% for ventricular shunts, 40% for ventricular assisted devices)
- Native valve endocarditis
- Central venous catheters
- Urinary Tract Infection
- Cystic Fibrosis infections
- COPD (Chronic Obstructive Pulmonary Disease) infections
- Otitis media
- Non-healing chronic wounds
- Hospital Acquired Pneumonia
- Clostridium Difficile Infection CDI
- Kidney infections,
Current Treatment Approaches
In patients, biofilms that form are resistant to the host's endogenous defences. Biofilms causing infections are progressive, and in some cases can become a chronic problem. They are treated with a combination of antibacterial therapies and tissue debridement. In the case of implant-associated infections treatment includes the delivery of high dose antibiotics according to the severity of infection, and if symptoms persist, then surgical replacement must take place.
Adversely, the large doses of antibiotics used to treat biofilms clinically have also contributed to the development of antibiotic-resistant bacteria strains. Also it has been seen that some bacteria within biofilms, called “persister cells,” are dormant variants that exhibit antibiotic tolerance and can become active when the therapy is withdrawn.
See also Infection Control
Due to the widespread distribution of biofilms in diseases and their resilience to numerous antimicrobial treatments, biofilm research is receiving more attention. Owing to increasing antimicrobial resistance, the focus of current research is shifting from targeting bacterial growth/division that causes cell death or dormancy, towards novel approaches.
The 4 videos below (approx 10 minutes in total) show some of these novel approaches, take a look.
- Jamal M, Ahmad W, Andleeb S, Jalil F, Imran M, Nawaz MA, Hussain T, Ali M, Rafiq M, Kamil MA. Bacterial biofilm and associated infections. Journal of the Chinese Medical Association. 2018 Jan 1;81(1):7-11. Available from: https://www.sciencedirect.com/science/article/pii/S1726490117302587 (last accessed 7.10.2019)
- British Society for Immunology Biofilms and their role in pathogenesis Available from: https://www.immunology.org/public-information/bitesized-immunology/pathogens-and-disease/biofilms-and-their-role-in (last accessed 7.10.19)
- Khatoon Z, McTiernan CD, Suuronen EJ, Mah TF, Alarcon EI. Bacterial biofilm formation on implantable devices and approaches to its treatment and prevention. Heliyon. 2018 Dec 1;4(12):e01067. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6312881/ (last accessed 7.10.19)
- biofilm What Are Bacterial Biofilms? A Six Minute Montage Available from: https://www.youtube.com/watch?v=lpI4WCM_9pM (last accessed 7.10.19)
- NIH Metabolomics of Bacterial Biofilms Available from: https://www.youtube.com/watch?v=0DSA_8t4-UA&feature=youtu.be (last accessed 8.10.2019)
- UTSWmed Breakthrough discovery to treat prosthetic joint infections Available from: https://www.youtube.com/watch?v=2LDNrZldtAU&app=desktop (last accessed 8.10.2019)
- MicroGen DX Javad Parvizi, MD on Biofilm Infections and Next-Gen Sequencing Available from: https://www.youtube.com/watch?v=8X5SIVbsoao (last accessed 8.10.2019)
- Vomaris Innovations Wound Biofilm Formation and Disruption by Electric Field Available from: https://www.youtube.com/watch?v=xO9LkAAdooU&app=desktop (last accessed 8.10.2019)