Chapter 15 - Microbial Mechanism Flashcards
________ is the ability of a microbe/pathogen to cause disease in a host.
Pathogenicity
______ is the enhanced ability of a pathogen to cause infection.
Virulence
_______ is the characteristic or trait of the pathogen that makes it harmful. This can be capsules, toxins, antigenic variation, etc.
Virulence Factor
________ are the different ways by which a microbe can cause an infectious disease.
Mechanisms of Pathogenicity
_______ are non-oral entry, pathogens can be directly deposited into tissue or bloodstream, and typically involve an injection into a blood vessel.
Parenteral route
______ is the number of pathogens required to make 50% of the population sick. _____ measures the virulence of a microbe and infectious pathogens have varying values.
ID50 (Infectious Dose 50)
Low ID50 is an indicator of _______.
High infectiousness -> very virulent/dangerous
High ID50 is an indicator of ______.
Low infectiousness -> low virulent/dangerous
______ is the amount of toxin required to kill 50% of the population and measures the potency of a toxin. Toxigenic pathogens have varying values.
LD50 (Lethal Dose 50)
Low LD50 means _______.
High lethality and very toxic.
High LD50 means _____.
low lethality/ not very toxic.
_______ is the ability of pathogens to attach to host tissue/cells.
Adherence (adhesion/attachment)
______ are substances on the pathogen that bind to receptors on the host cell.
Bacterial Adhesins (ligands)
______ are found on Streptococcus mutans.
Capsules
_______ are found on E. coli O157:H7.
Fimbriae
______ are found in the cell wall of Streptococcus pyogenes.
M proteins
______ can be found in the cell wall of Neisseria gonorrhaea.
Opa proteins
_________ are found on Treponema pallidum.
Hooks
_________ helps form blood clots, which stop blood flow, and host defenses cannot reach the bacterium. Bacteria can also surround themselves inside a clot.
Coagulase
_______ breaks down blood clots surrounding the bacterium, which allows the bacterium to spread freely throughout the body.
Kinase
_______ breaks down hyaluronic acid in connective tissue.
Hyaluronidase
_______ breaks down collagen in connective tissue.
Collagenase
________ destroys IgA.
IgA Protease
______ are poisonous substances produced by pathogens that can produce fever, cardiovascular problems, diarrhea, and shock.
Toxin
_______ is the ability of a pathogen to produce a toxin.
Toxigenicity
______ is the presence of toxins in the bloodstream.
Toxemia
______ is a chemically modified toxin which is no longer toxic. ______ is non-toxic toxin that stimulates the immune system to make antibodies.
toxoid
______ is an antibody against a toxin (NOT towards the bacteria)
Antitoxin
Toxin production involves bacterial _____ that carry genes for toxins.
Plasmids
________ act as an antigen that triggers an immune response to produce Ab’s. An example of ______ is toxin.
Immunogen
A _______ immunogen is a good stimulator of immune response, meaning that antibodies are made which result in no fever. An example of _____ Immunogen would be protein toxins.
Strong
A ______ immunogen is a poor stimulator of the immune response, meaning no antibodies are made, resulting in a fever. An example of ________ immunogens would be lipid and polysaccharide toxins.
Weak
______ are secreted by living cells; mostly gram-positive bacteria, some gram-negative bacteria, and do not usually have a fever
Exotoxins
_____ are part of the dying bacterial cell wall, are secreted by gram-negative bacteria only, and are lipid portions of the LPS that break off and result in fever.
Endotoxins
______ are composed of proteins, are highly toxic, have a low LD50, do not induce fever, and are neutralized by antitoxin.
Exotoxins
______ are composed of lipids, have a high LD50, low toxicity, induce fever, and are not neutralized by antitoxin.
Endotoxins
_______ are Ag that cause a very strong immune response, cause proliferation of T cells, that release cytokines, which induce fever, nausea, vomiting, and shock.
Type 1 (Superantigen)
(Only exotoxin to induce a fever)
_______ cause lysis of host cells by disrupting their C.M., by forming channels in the phospholipid layer.
Type 2 (Membrane-Disrupting Toxins)
______ consists of 2 parts, is the most common type of exotoxin, and works by inhibiting protein synthesis in host cells.
Type 3 (A-B Toxins)
_________ can contaminate the food supply, provoke an allergic response, and are carcinogenic. Aflatoxin is an example of ________.
Fungal Toxins
________ causes damage to intestinal lining resulting in diarrhea or dysentery, avoids host defenses by growing in phagocytes and antigenic variation.
Parasitic Protozoa
________ are not very pathogenic, use the host’s nutrients or tissue without killing the host, and are present in the GI tract in large numbers interfering with host food absorption. This leads to symptoms of fatigue and weight loss.
Parasitic Helminths
