Answered You can hire a professional tutor to get the answer.
I need some assistance with these assignment. development of antibiotics as a new era in disease treatment Thank you in advance for the help!
I need some assistance with these assignment. development of antibiotics as a new era in disease treatment Thank you in advance for the help! Host susceptibility is an important virulence factor for bacteria. The first important step in bacterial pathogenesis is adherence to a host cell. This occurs by means of pili, which consist of long rods that extend out from the bacterial surface. The tips of the pili contain proteins that attach to host cell receptors. In some cases, "pilin, the protein subunits of the pilus shaft, attach to the host cell's receptors. In addition to pili, bacterial surface proteins called adhesins attach firmly to the host cells". Sometimes the host makes antibodies against pili or adhesin proteins, and this induces the bacteria to make different types of adhesins.
Only Gramnegative bacteria make adhesins. the mechanism of how Gram-positive bacteria attach to a host cell is not known.
The virulence of many bacterial pathogens is due to the toxins they produce, which disrupt normal cell functions and cause cell death. Scholar and Pratt (2000) explain that "exotoxins are proteins that are excreted by dividing bacteria. Exotoxins that attack a variety of cell types are called cytotoxins". those that attack a particular cell type or tissue have specific names, such as neurotoxin, leukotoxin, hepatotoxin, or cardiotoxin. Exotoxins can be associated with a specific bacterial disease. In addition to toxic proteins, pathogenic bacteria also produce hydrolytic enzymes that degrade host tissues and disseminate bacteria within the host. Heat-shock proteins produced by bacteria stimulate autoimmune responses so that host antibodies and T-cells attack healthy host cells.
The essential property that differentiates antibiotics from antiseptics is that they are sufficiently selective to allow their use within the body, rather than just on the surface. This selective toxicity is not absolute but it is quantifiable as we shall see in chapter 6. There is, therefore, always room for improvements and developing drug licensing regulations seek improvements in the comparative safety of antibiotics. "Antibiotics work by destroying either the proteins that build a bacterium's cell wall or the protein-producing ribosome. The drug must inhibit the target bacteria at lower concentrations, usually much lower, than those concentrations that produce toxic effects in humans. Some antibiotics can be given in very high doses without toxic effects, e.g. penicillins, but others may produce serious toxicity at levels that are not much above those required for treatment of infection. Many alterations to antibiotics have been made to improve this selectivity. though with some antibiotics this is virtually impossible to achieve. .
