Chapter 15: Microbial Mechanism of Pathogenicity

Coagulases

are bacterial enzymes that coagulate (clot) the fibrinogen in blood.

Superantigens

are antigens that provoke a very intense immune response.

Coagulases

are bacterial enzymes that coagulate (clot) the fibrinogen in blood.

Superantigens

are antigens that provoke a very intense immune response.

Hyaluronidase

is another enzyme secreted by certain bacteria, such as streptococci.

waxy lipid

The (mycolic acid) that makes up the cell wall of Mycobacterium tuberculosis also increases virulence by resisting digestion by phagocytes, and the bacteria can even multiply inside phagocytes.

Membrane disrupting toxins

that destroy erythrocytes (red blood cells), also by forming protein channels, are called hemolysins.

adhesins

The attachment between pathogen and host is accomplished by means of surface molecules on the pathogen called or ligands that bind specifically to complementary surface receptors on the cells of certain host tissues.

Hemolysins

produced by streptococci are called streptolysins.

M protein

is found on both the cell surface and fimbriae.

Collagenase

breaks down the protein collagen, which forms the connective tissue of muscles and other body organs and tissues.

resistant portions

The toxin is contained in sclerotia, highly of the mycelia of the fungus that can detach.

microbes

The produce sur- face proteins called invasins that rearrange nearby actin filaments of the cytoskeleton.

Exotoxins

are produced inside some bacteria (mostly gram- negative) as part of their growth and metabolism and are secreted by the bacterium into the surrounding medium or released following lysis.

Pathogens

can gain entrance to the human body and other hosts through several avenues, which are called portals of entry.

Toxins

are poisonous substances that are produced by certain microorganisms.

Aflatoxin

is produced by the growth of the mold Aspergillus flavus.

Intoxications

are caused by the presence of a toxin; not by microbial growth.

bacterial proteins

They are that combine with a protein on macrophages; this non- specifically stimulates the proliferation of immune cells called T cells.

M protein thereby

The increases the virulence of the microorganism.

capacity of microorganisms

The to produce toxins is called toxigenicity.

Pathogenicity

is the ability to cause disease by overcoming host defenses, whereas virulence is the degree of pathogenicity.

Siderophores

are released into the medium, where they take the iron away from iron- transport proteins by binding the iron even more tightly.

natural source of LSD

The toxin itself, ergot, is an alkaloid that can cause hallucinations resembling those produced by LSD (lysergic acid diethylamide); in fact, ergot is a(n) .

potency of a toxin

The is often expressed as the LD50 (lethal dose for 50 % of a sample population)

Shock

caused by bacteria is called septic shock.

Membrane disrupting toxins

that kill phagocytic leukocytes (white blood cells) are called leukocidins.