Maybe it is not clear how I choose my random paper of the day. However, I am quite sure that everybody will understand why I chose the paper of W. Michael Dunne, Jr. (2002). How could I not choose a paper with such a great title: “Bacterial Adhesion: Seen Any Good Biofilms Lately?” I have to admit, I haven’t seen any biofilms lately. Or more correct: I was not aware of any biofilms around me lately, but I am sure there have been some as they can be found on a variety of “wet” surfaces like “contact lenses, ship hulls, dairy and petroleum pipelines, rocks in streams, and all varieties of biomedical implants and transcutaneous devices”. Biofilms are the results of a combination of aquatic bacterial populations, a surface and glycocalyx. The latter is the “slime” surrounding the bacteria and is mainly made of polysaccharides (sugars). The biofilm structure differs between the bacteria species. However, it seems true for all species that bacteria in biofilms are harder to destroy with antibiotics as their planktonic (solved) form. The “slime” of the biofilm helps to gather essential minerals and nutrients from the surrounding and protects the bacteria from enemies like antibiotics, bacteriophages and predators. Not all bacteria can bind on all surfaces. If a bacteria is near a surface, the net sum of different forces like e.g. electrostatic and hydrophobic interactions decides if the bacteria can dock on or not. These forces differ between different bacteria species. For example, in contrast to the most bacteria, which are negatively charged, Stenotrophomonas maltophilia is posetively charged at physiological pH and can therefore bind on negatively charged surfaces like Teflon where the other bacteria are repelled. The adhesion process is strengthened by production of adhesin and/or receptor-specific ligands on the surface or on structures extending from the cell surface, such as pili, fimbriae, and fibrillae. The method can differ in the same bacteria depending on the surface: “In the case of Vibrio cholerae El Tor, a toxin-coregulated pilus is used […] during the process of human infection, whereas […] adhesin [is] used to anchor to abiotic surfaces in an aquatic environment.“ Adhesion of a bacteria species can enhance the adhesion of another bacteria species by forming a heterogeneous biofilm. This makes it hard/impossible to prevent biofilms on certain surfaces even though they are known to cause infections, biofouling and corrosion. However, biofilms can also be beneficial for nitrogen fixation and bioremediation of wastewater. Summing up: Biofilms are universal and as Dunne wrote: “One has only to experience the process of cleaning a J trap in a clogged sink drain to fully appreciate the potential magnitude of bacterial biofilms and the process of biofouling on a small scale.” "Bacterial adhesion: seen any good biofilms lately?"
W. Michael Dunne Jr. Clinical microbiology reviews 15.2 (2002): 155-166.
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IdeaI love to increase my general science knowledge by reading papers from different fields of science. Here I share some of them. Archiv
März 2018
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