WHAT IS BIOFILM?

Acute infections caused by pathogenic bacteria have been studied extensively for well over 100 years. These infections killed millions of people in previous centuries but have been combated effectively by the development of modern vaccines, antibiotics and infection control measures. Most research into bacterial pathogenesis has focused on acute infections, but these diseases have now been supplemented by a new category of chronic infections caused by bacteria growing in slime-enclosed aggregates, known as biofilms. Biofilm infections, such as pneumonia in cystic fibrosis patients, chronic wounds, chronic otitis media and implant- and catheter-associated infections, affect millions of people worldwide each year, resulting in many deaths. In general, bacteria have two life forms during growth and proliferation. In one form, the bacteria exist as single, independent cells (planktonic) whereas in the other form, bacteria are organized into sessile aggregates. The latter form is commonly referred to as the biofilm growth phenotype. Acute infections are assumed to involve planktonic bacteria, which are generally treatable with antibiotics, although successful treatment depends on accurate and fast diagnosis. However, in cases where the bacteria succeed in forming a biofilm within the human host, the infection often turns out to be untreatable and will develop into a chronic state.

The important hallmarks of chronic biofilm-based infections:

Extreme resistance to antibiotics and many other conventional antimicrobial agents
Extreme capacity for evading the host defenses

WHAT ARE BACTERIAL BIOFILMS?

Biofilm formation is considered to be the way microbes adapt to hostile environments. Bacterial biofilm is widely found in natural environments with water, and also in human diseases, especially in patients with indwelling devices for the purpose of medical treatments. With the progress of medical sciences, more and more medical devices and/or artificial organs are applied in the treatment of human diseases; increasing the number of surfaces that are at risk of biofilm formation.

Biofilm is a structured consortium attached on a living or inert surface formed by microbial cells. These cells are adhered to each other and are surrounded by the self-produced extracellular polymeric matrix, known as biofilm.

The typical development of biofilm includes several stages:

Attachment to a surface

Formation of micro-colonies

Development of young biofilm

Differentiation of structured mature biofilm

Dispersal of mature biofilm