Evidence for Microbial Biofilms in Cholesteatomas

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Abstract
IN NATURE, bacteria most commonly exist as microbial communities known as biofilms. These biofilms provide an environment in which the bacteria are protected from external deleterious conditions. Bacteria can become free from the biofilm and become motile, free-swimming organisms. Hence, bacteria exist in 2 principal forms, as motile, replicating cells (planktonic form) or as quiescent cells, within a hydrated matrix of polysaccharide and protein (sessile form). Many bacteria, typically Pseudomonas species, Staphylococcus species, and Haemophilus influenzae, have the capacity to adhere to inanimate as well as living surfaces. Once adherent, the bacteria secrete a complex polysaccharide matrix in which the bacteria become embedded. These microcolonies gradually enlarge and then through a process called "quorum sensing," form large colonies of sessile bacteria. Bacteria in these biofilms are resistant to antibiotics by mechanisms that are different than those used by planktonic bacteria.1 The exact mechanism of antibiotic resistance of bacteria within biofilms is unknown but probably involves a number of factors including the direct protection afforded by the biofilm itself,2 alterations in the local environment,3,4and changes in bacterial phenotype.5