You may not be familiar with the term “biofilm,” but you have it on a regular basis. The plaque that forms on your teeth and causes decay is one type of bacterial biofilm. That “stuff” that clogs your drains is also biofilm. If you have ever walked in a stream or river, you may have slipped on biofilm-coated rocks.
Biofilm not only lives on surfaces in nature, populations of these microorganisms are in your gut and that of your pet. Biofilm microorganisms are of two types: free-living planktonic microbes and colonizing sessile biofilm organisms. They produce a matrix that encases them so they strongly adhere to surfaces and resist dislodgement. The biofilm of healthful commensal microorganisms greatly contributes to intestinal barrier function and colonization resistance. Disrupted, healthful biofilm permits colonization and biofilm formation by potential pathogens such as Klebsiella pneumonia, E. coli, and Candida albicans.
Microbes residing within biofilms may consist of one or more species that communicate and collaborate with one another in a heterogeneous community. Biofilm formation appears to be initiated by contact with a surface. It is a survival mechanism that triggers regulation of genes such as those mediating motility and growth as well as expression of genes regulating synthesis of exopolysaccharides and exoproteins. The presence of calcium, iron, and magnesium is essential for biofilm creation and serves to cross-link the anionic regions of polymers.
Life within a biofilm provides significant survival advantages to bacteria and yeasts. Biofilms adhere to surfaces and resist dislodgement. Biofilm formation may be viewed as an adaptive mechanism that enables microbes to persist and reproduce in an advantageous micro ecological niche. They are protected from predation by phages and protozoa as well as from host immune responses and are highly resistant to the spectrum of antimicrobials ranging from germicides and disinfectants to antibiotics and bacteriocins produced by probiotics. Sessile biofilm microorganisms are 10 to 1000 times more resistant to antibiotics compared to planktonic forms of the same strain.
It is believed that antimicrobial resistance to biofilm-associated organisms is due to impaired ability to penetrate the biofilm matrix, reduced microbial growth rates, biofilm-induced expression of resistance factors, and other biofilm-associated physiologic changes that decrease the susceptibility to antimicrobials. Eradication of pathogen-associated biofilm is critical to successful elimination of these harmful pathogens and restoration of healthful biofilm communities.