why do bacteria in a biofilm have different characteristics than free-floating bacteria
Biofilm Bacteria living in a biofilm usually have significantly different properties from free-floating bacteria of the same species, as the dense and protected environment of the film allows them to cooperate and interact in various ways.[34] One benefit of this environment is increased resistance to detergents and antibiotics, as the dense extracellular matrix and the outer layer of cells protect the interior of the community. In some cases antibiotic resistance can be increased a thousandfold.[35] Lateral gene transfer is often facilitated within bacterial and archaeal biofilms[36] and leads to a more stable biofilm structure.[37] Extracellular DNA is a major structural component of many different microbial biofilms.[38] Enzymatic degradation of extracellular DNA can weaken the biofilm structure and release microbial cells from the surface.
Escherichia coli Escherichia coli (/ˌɛʃɪˈrɪkiə ˈkoʊlaɪ/;[1] also known as E. coli) is a Gram-negative, facultative aerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms (endotherms).[2][3] Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in their hosts, and are occasionally responsible for product recalls due to food contamination.[4][5] The harmless strains are part of the normal microbiota of the gut, and can benefit their hosts by producing vitamin K2,[6] and preventing colonization of the intestine with pathogenic bacteria, having a symbiotic relationship.[7][8] E. coli is expelled into the environment within fecal matter. The bacterium grows massively in fresh fecal matter under aerobic conditions for 3 days, but its numbers decline slowly afterwards.[9]