Biofilms are estimated to be responsible for 80% of all human infections and cost industry, cities and hospitals in excess of $500 billion each year.
Biofilms are formed when bacteria and/or fungi adhere to surfaces and excrete a glue-like substance that acts as an anchor and provides protection from the environment. Biofilm formation can make bacteria up to 1000 times more resistant to antibiotics, antimicrobial agents, disinfectants and the host immune system and are acknowledged to be one of the main contributors to the “antibiotic resistance crisis”xvi.
Biofilms can form on both living and non-living surfaces including teeth (plaque and tartar), skin (wounds and diseases like seborrheic dermatitis), medical devices (catheters and endoscopes), kitchen sinks and counter tops, food and food processing equipment, hospital surfaces, pipes and filters in water treatment plants and oil, gas and petrochemical process control facilities.
Biofilm related infections are difficult to treat and they commonly manifest themselves as chronic or recurrent in nature. According to an estimate by the National Institute of Health (NIH, USA), approximately 80% of all human bacterial infections are caused by biofilmsxvii. These structures are implicated in a range of health concerns such as periodontal disease, the healing of chronic wounds, medical device associated infection, inflammatory skin conditions, Hospital-Acquired Infections (HAIs) and food safety.
It was not until the 1990s that the elaborate organization of attached bacteria was identified as a biofilmxviii. Research on biofilms has only progressed rapidly in the last decade, leading to a greater understanding of the role biofilms play in infection and antimicrobial resistance. New understandings of how biofilms develop and propagate will suggest ideas for preventing and eliminating them.
DEVELOPMENT OF BIOFILMS
Stage 1. Initial attachment:
Colonizing bacteria anchor to a surface through basic adhesion techniques. This is when the biofilm is weakest, so many makers of medical devices, such as catheters, design their equipment in a way that attempts to disrupt initial adhesion.
Stage 2. Irreversible attachment:
After the cells aggregate they form micro colonies and excrete EPS or “slime” to form an irreversible attachment that can weather shear forces and maintain a steadfast grip on the surface.
Stage 3. Maturation I:
The biofilm is fully formed. As it matures the biofilm becomes a multi-layered cluster.
Stage 4. Maturation II:
The biofilm continues to grow and become three-dimensional. As the biofilm matures it is able to provide protection against the host immune system, anti-microbials, disinfectants and antibiotics.
Stage 5. Dispersion:
The biofilm reaches its critical mass and releases planktonic bacteria to continue colonizing other surfaces.