Microbiology McGrawhill Chapter 35
The ID50 refers to the
number of organisms in the initial inoculum required to cause infection in 50% of hosts.
Pathogens produce virulence factors primarily to ______
outcompete host cells for resources
One strategy for exploiting host cells that is used by certain bacteria such as Listeria, Shigella, and Rickettsia is to ______
use the actin filaments of the host cytoskeleton to facilitate motility through the host cell thereby enhancing infection of neighboring cells
Choose all of the following attributes that are necessary for any bacterial pathogen to attach to and colonize a host cell.
-Compete for nutrients -Capsule production -Utilize spikes to attach to host cells -Ability to survive new host environment -Presence of fimbriae
Vector-borne transmission
-anthropods -animals -fleas -mosquitoes -ticks
Airborne transmission
-coughing -sneezing -droplet nuclei -dust
contact transmission
-kissing -sex -touching
Choose which of the following characteristics describe endotoxins
-lipopolysaccharide -lipid A -gram-neg infections -produce fever -usually on chromosomal genes -heat stable -weakly immunogenic -cell wall material -can cause septic shock
Choose which of the following characteristics describe exotoxins
-protein -no fever -carried on plasmids -excreted by living cells -heat labile -highly toxic -antigenic
Vehicle transmission
-surgical instruments -fomites -shared cups
Rank the following stages of infectious disease progression in the correct order as they occur. 1) exposure 2) prodrome 3) illness 4) incubation 5) convalescence
1,3,4,2,5
Exotoxins (Heat stability)
Easily heat inactivated
Endotoxins (Heat stability)
Fairly heat stable
Exotoxins (Toxicity)
Generally very toxic
Exotoxins (Source--type of bacteria)
Gram-pos and Gram-neg bacteria
Endotoxins (Chemical structure)
LPS (Specifically Lipid A)
This type of pathogen cannot grow outside a host cell
Obligate intracellular pathogen
Endotoxins (Source--type of bacteria)
Only gram-neg bacteria
Endotoxins (Toxicity)
Small, localized amounts tend not to cause problems; very toxic once it becomes systemic
Endotoxins (Location in the bacterium)
Part of the outermembrane of gram-negative bacteria
Exotoxins (Chemical structure)
Protein
Pathogenicity islands
Segments of the genome that code for virulence factors
virulence
The magnitude of harm caused by an organism
invasiveness
The ability of a pathogen to spread to neighboring cells and adjacent tissues
Pathogenicity
The potential to cause disease
colonization
a microbe establishing itself and multiplying on a body surface.
primary pathogen
a microbe that causes disease in otherwise healthy individuals.
opportunistic pathogen
a microbe that causes disease only when the body is already compromised in some way.
Exotoxins (Location in the bacterium)
cytoplasmic protein;may or may not be secreted
virulence
degree of pathogenicity (disease causing ability) of a microbe.
