The answer to whether these microbial structures can make you sick is a definitive yes. Biofilms are complex communities of microorganisms, such as bacteria and fungi, that stick to a surface and encase themselves in a protective, self-made barrier. This communal lifestyle allows pathogens to survive conditions that would normally eliminate them, making them a major factor in persistent and difficult-to-resolve infections. The microorganisms within these structures exhibit dramatically different behaviors compared to their free-floating counterparts, which is why certain illnesses become chronic.
What Exactly Is a Biofilm?
A biofilm is a highly organized, cooperative community of microbes attached to a living or inert surface. Formation begins when free-floating microbes adhere to a surface and secrete a slimy, protective matrix. This matrix is known as the Extracellular Polymeric Substance (EPS), and it constitutes up to 90% of the biofilm’s total mass.
The EPS is a complex mixture of biopolymers, primarily composed of polysaccharides, proteins, and extracellular DNA. This substance provides mechanical stability and mediates interactions between the individual cells. Once established, the biofilm grows into a three-dimensional structure that can harbor multiple species of microorganisms. The microbes within this architecture are physiologically distinct from their planktonic, or single-celled, counterparts.
Mechanisms of Biofilm Disease
The physical structure of the biofilm is the primary factor causing persistent and difficult illnesses. Microorganisms living within the EPS matrix exhibit a profound increase in tolerance to standard treatments compared to free-floating cells. The EPS acts as a physical and chemical barrier that slows the penetration of antimicrobial agents, preventing a sufficient concentration of medicine from reaching the microbes.
The concentration of antimicrobial agents required to affect microbes within a biofilm can be hundreds of times higher than the amount needed for free-floating cells. Furthermore, bacteria deep within the structure often enter a state of slow growth or dormancy. This protects them from many antibiotics that specifically target rapidly dividing cells. These slow-growing microbes, called persister cells, can survive therapy and later reactivate to cause infection recurrence.
The biofilm also provides a powerful defense against the body’s immune system. The thick, dense EPS matrix physically shields the microbes from immune cells, such as phagocytes, which engulf and destroy invading pathogens. By preventing immune cells from reaching the infection site, the biofilm establishes a long-term presence. This unsuccessful attempt by the immune system to clear the infection often results in chronic inflammation and associated tissue damage.
Common Biofilm-Associated Infections
Biofilm formation is a major factor in many chronic infections that resist standard medical intervention. For instance, patients with cystic fibrosis frequently develop persistent lung infections involving Pseudomonas aeruginosa, which forms structured biofilms deep in the airways. Chronic wound infections, including diabetic foot ulcers, are highly associated with biofilms, preventing the body from progressing through normal healing stages.
Biofilms are a significant source of illness when they colonize medical devices inserted into the body. Inert surfaces, such as prosthetic joints, heart valves, and intravenous catheters, provide an ideal attachment point for microorganisms. Once a biofilm forms on a device, it can lead to a localized infection that may seed bacteria into the bloodstream, potentially causing a dangerous systemic infection. Biofilms on medical devices are responsible for a large percentage of hospital-acquired infections worldwide.
A common example of a biofilm is dental plaque, which forms daily on the surface of teeth. If not removed, the metabolic activity of the microbes within this plaque can lead to gingivitis and periodontitis. This illustrates the natural tendency of microorganisms to adopt this community lifestyle on surfaces throughout the body.
Treating Biofilm-Related Illnesses
The inherent resistance mechanisms of the biofilm structure present substantial challenges to treatment. Standard courses of antibiotics often fail to completely eradicate the infection, leaving behind surviving persister cells that trigger recurrence. Since the minimum inhibitory concentration (MIC) for biofilm-embedded bacteria is so high, administering a dose strong enough to eliminate the infection often risks toxicity to the patient.
Current strategies often involve combination therapies or the use of agents that target the biofilm structure itself. For infections involving medical devices, the most reliable method requires the physical removal and replacement of the infected implant or catheter. Researchers are also investigating novel treatments, such as compounds that break down the EPS matrix or agents that interfere with bacterial communication, known as quorum sensing. These innovative approaches aim to dismantle the protective structure before or alongside conventional antimicrobial drugs.