CHAPTER 15

• What are some examples of the portals of entry?

  Mucous membranes, skin (parenteral route), respiratory tract, gastrointestinal tract
• List some ways in which bacteria can damage host cells?


  -siderophores

  -direct damage

  -exotoxins

  -endotoxins

  -cytopathic effects
• What are some methods of penetration for bacteria?

  invasin, enzymes
• What are some ways that bacteria can penetrate host cells?

  -invasins
• What are some methods used by bacteria to evade host defenses?

  -capsules

  -cell wall components

  -antigenic variation
• what is pathogenicity?


  ability to cause disease
• what is virulence?


  degree of pathogenicity
• What is the parenteral route of entry?

  deposited directly into tissue when barriers are penetrated
• Most pathogens have a preferred _____ __ _____

  portal of entry
• What does ID50 describe?

  infectious dose for 50% of a sample population
• What does ID50 measure?

  virulence of a microbe
• What is LD50?


  lethal dose for 50% of a sample population (tissue or cell)
• what does LD50 measure?

  potency of a toxin
• How can you tell an organisms preferred portal of entry?

  Lowest # of microbes or endoscopes required means that it is easiest to infect through this portal of entry
• What is adherence?


  process of pathogen attaching to host tissue
• What are some different modes of adherence for bacteria?

  -adhesions

  -glycocalyx

  -fimbriae

  -pili

  -Opa proteins
• What are adhesins aka ligands?

  proteins on pathogen that bind to host cell receptors
• How does a capsule, glycocalyx, or biofilm help an organism avoid our defenses?

  -covers antigens preventing antibodies from binding to them
• How do proteases aid in a microbes pathogenicity?

  virulence factors break down host antibodies to evade being phagocytized
• Name the bacteria that have capsules

  -Yersenia Pestis

  -Streptococcus pneumoniae

  -Klebsiella pneumoniae

  -Haemophilus influenza

  -Pseudomonas aeruginosa

  -Neisseria meningitidis

  -Cryptococcus neoformans
• What are M proteins and what organism has them?

  Bacterial surface proteins that help bacteria resist phagocytosis

  Streptococcus pyogenes
• What are Opa proteins and what organism has them?

  proteins that allow attachment to host cells

  -Neisseria gonorrhoeae
• What is mycolic acid and what organism has it?

  Waxy lipid that helps resist digestion

  -Mycobacterium tuberculosis
• What are coagulases and what organism has the enzyme?

  enzymes that help bacteria form fibrin from our blood plasma into clots. This helps them hide from our immune cells.
• What are kinases?

  enzymes that help break down fibrin clots
• What is hyaluronidase?

  enzyme that digests polysaccharides that holds cells together
• What is collagenase?

  an enzyme that breaks down collagen
• What are IgA proteases?

  enzymes that destroy IgA antibodies
• How do Hyaluronidase and collagenase help bacteria?

  Helps to break down tissue and invade deeper into our tissue
• What is antigenic variation?

  The ability of pathogens to change their surface antigens to evade the immune system
• What are some examples of organisms that alter their surface antigens?

  -Trypanosoma sp

  -Influenza

  -COVID-19
• How does antigenic variation increase an organisms virulence?

  -renders antibodies ineffective

  -makes vaccines less effective
• What are invasins?


  surface proteins that rearrange actin filaments of the cytoskeleton to cause membrane ruffling
• What bacteria use actin filaments to move from one cell to the next?


  Shigella sp and Listeria sp
• ____ is required for most pathogenic bacteria


  iron
• what are siderophores?

  proteins that bind iron more tightly than host cells
• What are some ways that bacteria can cause direct damage to host cells?


  -produce waste products (change in pH)

  -Multiply in host cell and cause rupture

  -Toxins
• What is a toxin?

  poisonous substance produced by microbes
• What is toxigenicity?


  ability of a microbe to produce a toxin
• What is toxemia?


  Toxemia is a condition characterized by the presence of toxins in the blood.