In order to be a successful pathogen, a bacterium must perform several mechanisms- attachment, invasion, intoxication and resistance to attack by the immune system of the host. The bacterium has adaptation enabling it to perform all of these mechanisms. Due to the short regeneration time of bacterium, evolution can occur at a much faster rate than humans, with most bacteria multiplying (in optimum conditions) every 20 minutes, instead of every 20 years as it takes humans. This means bacteria can evolve and mutate optimising their mechanisms of pathogenesis and causes them to acquire resistance both to our immune responses, and the medical intervention we use in an attempt to stop them. The rate of bacterial resistance is building, and a recent
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Here, I will explore how bacterium have adapted to become successful pathogens through the development of pilli, capsules and toxins, as these are 3 of many bacterial adaptations which represent the ways bacterium have evolved to efficiently invade and kill host cells.
The first step of a bacteria killing eukaryotic cells thus becoming pathogenic is adhesion to the cell. This can be achieved through pilli, which are filaments on the surface of the bacterium, which can grow up to several microns in length. They are formed by the polymerisation of protein subunits called pilin. Pilli are used in bacterial conjugation as well as adhesins, to attach bacteria to their host cells. This is achieved through tip adhesins on the end of pilli such as FimH and PapG. An example of pilli adhesion can be seen in uropathogenic E. coli. this is the leading cause of urinary tract …show more content…
It can be argued that toxins are entirely responsible for pathogenesis as disease can be replicated through injection of the toxin alone. Also, many vaccinations can be formed from attenuated bacterium which have the toxin inactivated through formaldehyde treatment, hence making them harmless to patients. This is called a toxoid vaccination. The risk of this form of vaccination is if the bacteria mutate and reactivate the toxin, hence causing an actually pathogenic infection. An example of toxoid vaccinations are those used to vaccinate against diphtheria and tetanus. Toxins can be classified as endotoxins or exotoxins. An endotoxin is cell-associated, in that is a part of the bacterium rather than a secreted substance. An example of this is lipopolysaccharide(LPS), which is the main component of the outer membrane of gram negative bacteria. LPS triggers an innate immune response via binding to LPS binding protein which binds to CD14 receptor on nearby macrophage triggering cytokine release of IL-1, IL-6, TNF-alpha and prostaglandins. These cause an inflammatory response. The other type of toxins are exotoxins which are secreted from bacteria and damage host cells. A subset of exotoxins are superantigens, which are type 1 toxins. These are antigens which activate T-cells indiscriminately, and are able to activate up to 20% of the body’s T-cells (normally antigens
Here, I will explore how bacterium have adapted to become successful pathogens through the development of pilli, capsules and toxins, as these are 3 of many bacterial adaptations which represent the ways bacterium have evolved to efficiently invade and kill host cells.
The first step of a bacteria killing eukaryotic cells thus becoming pathogenic is adhesion to the cell. This can be achieved through pilli, which are filaments on the surface of the bacterium, which can grow up to several microns in length. They are formed by the polymerisation of protein subunits called pilin. Pilli are used in bacterial conjugation as well as adhesins, to attach bacteria to their host cells. This is achieved through tip adhesins on the end of pilli such as FimH and PapG. An example of pilli adhesion can be seen in uropathogenic E. coli. this is the leading cause of urinary tract …show more content…
It can be argued that toxins are entirely responsible for pathogenesis as disease can be replicated through injection of the toxin alone. Also, many vaccinations can be formed from attenuated bacterium which have the toxin inactivated through formaldehyde treatment, hence making them harmless to patients. This is called a toxoid vaccination. The risk of this form of vaccination is if the bacteria mutate and reactivate the toxin, hence causing an actually pathogenic infection. An example of toxoid vaccinations are those used to vaccinate against diphtheria and tetanus. Toxins can be classified as endotoxins or exotoxins. An endotoxin is cell-associated, in that is a part of the bacterium rather than a secreted substance. An example of this is lipopolysaccharide(LPS), which is the main component of the outer membrane of gram negative bacteria. LPS triggers an innate immune response via binding to LPS binding protein which binds to CD14 receptor on nearby macrophage triggering cytokine release of IL-1, IL-6, TNF-alpha and prostaglandins. These cause an inflammatory response. The other type of toxins are exotoxins which are secreted from bacteria and damage host cells. A subset of exotoxins are superantigens, which are type 1 toxins. These are antigens which activate T-cells indiscriminately, and are able to activate up to 20% of the body’s T-cells (normally antigens