Biofilms in : Mixed species

Surface cities of microbes — plaque and catheters explain persistence, without a grow-your-own kit. J. William Costerton and colleagues popularized biofilm for sessile communities glued in their own matrix. Plaque is the everyday biofilm: mixed oral species on teeth, fed by sugars and time.

Catheters, joints and valves can host films that shrug off doses that kill planktonic cells. Extracellular polymeric substance — sugars, proteins, DNA — holds water and slows some drugs. Many species use chemical signals to coordinate group behavior once density rises — a concept, not a home experiment.

Reviews often estimate that a majority of chronic device-related infections involve biofilm; the exact share is debated. A biofilm is a community stuck to a surface and wrapped in a homemade matrix, not a lonely floating cell. Plaque and catheter films show why a drug that works in a flask can fail on a surface.