Bacterial Biofilms

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Once the human body has been exposed to, and therefore infected by foreign bacteria, the infectious agents travel through the body via the bloodstream and the lymph nodes. After this infection occurs these bacteria now, in the body are planktonic. This means they are individual, free swimming, and virtually functioning as single celled organisms. When these bacteria are threatened by the host’s immune system or antibiotics they form biofilms. A biofilm is a thin coating of organic as well as inorganic matter that contains bacteria that have fused together and permanently anchored themselves to an object or body surface in contact with water. Bacterial biofilms commonly form on teeth, heart valves, urinary tracts, and even the inner lining of …show more content…
Non-specific immunity can oppose any pathogen rather than target a specific pathogen. The first line of defense within non-specific immunity includes intact skin, mucous membranes and their secretions, and normal microbiota. The second line of defense within non-specific immunity includes phagocytic white blood cells, inflammatory responses, fever, and antimicrobial substances. The human body’s third line of defense is specific immunity. Specific resistance includes specialized adaptive lymphocytes such as B cells and T cells and antibody production. Antibodies produced by B cells coat the surface of a pathogen and act in neutralization, opsonization, and complement activation. Neutralization occurs when the pathogen is unable to bind and infect host cells because it is covered with antibodies. Osponization is like a flagging system. In this process, pathogens that have been seized by antibodies stick out like red flags; this alerts macrophages, neutrophils and other phagocytic cells to entomb and kill the bacteria. Complement activation directly clears infected cells, and destroys or lyses the foreign microbes. T cells, which include CD8+ and CD4+ cells kill infected cells and activate other immune cells. Cytokines are small proteins secreted by immune cells. They are key in immune cell growth, activation, and …show more content…
The planktonic bacteria attach to host proteins. These irreversible attachments signal the bacteria to create a biofilm. More and more bacteria anchor themselves permanently using cell adhesion structures such as pili and receptors called epitopes. This encourages bacterial multiplication and provides convenient sites for adhesion. The bacteria secrete an extracellular slimy substance comprised of proteins, polysaccharides, and nucleic acids to build the protective matrix biofilm structure. The bacteria now communicate by means of quorum sensing and use inducers to regulate gene expression within the bacterium. Quorum sensing is a bacterial mechanism entailed by consistent production and secretion of signaling molecules called inducers that creates a constant stimuli and response system that promotes biofilm formation. The biofilm grows by means of cell division and recruitment. The development of this complex biofilm makes the community of bacteria resistant the host’s immune response and to antibiotic

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