Microbial biofilms are structured communities of bacterial cells enclosed in a self-produced matrix that provides a protective shield for bacteria to thrive and resist damage from many extreme environmental threats, such as antimicrobials and host defense mechanisms. Biofilm encased microbes are almost universally resistant to disinfectants and antibiotics, which can lead to prolonged and chronic infection, amputation, long-term disability, and death. Conventional antimicrobial drugs were not developed to target bacteria growing as biofilms and therefore are often poorly effective against biofilm containing infections. Biofilms also facilitate the spread of antibiotic resistance.
The presence of biofilms is implicated in chronic wounds, diabetic foot ulcers, urinary tract infections (UTIs), upper and lower respiratory tract diseases, native valve endocarditis, chronic otitis media, eye infections, and periodontitis.1 Biofilms can also develop on medical devices such as orthopedic prostheses, artificial cardiac valves, coronary stents, intravascular and urinary catheters, neurosurgical, cochlear, and breast implants, dentures, and ventricular-assist and ocular devices.1
Microbion is developing novel therapeutics to effectively manage these difficult to treat, biofilm-associated diseases.
Major mechanisms of biofilm antibiotic resistance
- Slow, incomplete, or ineffective antibiotic penetration into the biofilm matrix itself.
- Nutrient-limitation-mediated stress response, resulting in a much slower rate of growth and higher resistance to antibiotics.
- Alteration of microenvironments within the biofilm, such as pH gradients, that neutralize the action of antibiotics.2
- A subpopulation of “persister” microbes in biofilms that adopt a highly protected state with substantially reduced level of metabolic activity. If other bacteria in the biofilm become compromised, the persister cells tend to survive, and are then triggered to repopulate the biofilm.2
- Biofilms are breeding grounds for exchange of genetic elements, much of which can be found existing freely outside of cells, in a form known as eDNA.3
According to the National Institutes of Health (NIH), at least 80% of human infections involve bacterial pathogens growing as microbial biofilms.
- Magana M et al. Options and limitations in clinical investigation of bacterial biofilms. Clin Microbiol Rev. 31:e00084-16.
- Stewart PS and Costerton JW. Antibiotic resistance of bacteria in biofilms. Lancet. 2001;358:135-138.
- Ravaioli S et al. Biofilm extracellular-DNA in 55 Staphylococcus epidermidis clinical isolates from implant infections. Int J Artif Organs. 2011;34:840-846.