What is an example of a biofilm?

When Bacteria Stick Together: The Story of Biofilms

Next time you brush your teeth, think about this: the sticky film you’re removing is more than just debris—it’s a living community of bacteria known as a biofilm. Dental plaque is one of the most common and well-known examples of biofilms in everyday life. It forms when bacteria like streptococci and lactobacilli cling to the surface of teeth, multiply, and encase themselves in a slimy, protective layer made of sugars and proteins.

Biofilms aren’t unique to mouths. In fact, most bacteria can form them given the right conditions. These microbial cities allow bacteria to survive harsh environments, resist antibiotics, and even evade the immune system. Staphylococci, for instance, are notorious for forming biofilms on medical devices like catheters or joint replacements, sometimes leading to persistent infections.

What makes biofilms so resilient is their structure. Bacteria within a biofilm communicate and coordinate behavior, sharing nutrients and defending their colony. This social lifestyle makes them far more resistant than free-floating bacteria.

While plaque is the most familiar example, biofilms are everywhere—from the slime on rocks in a stream to the gunk inside pipes. Understanding them helps us fight infections, improve hygiene, and even design better medical equipment. But for now, your daily dental routine remains one of the simplest and most effective defenses against biofilm buildup.

So when you floss or rinse with mouthwash, remember: you're not just cleaning teeth—you're dismantling a microscopic fortress.