Studied by 10 people
what is the pathway for microbial mechanisms of pathogenicity
portals of entry
penetration/ evasion of host defenses
damage to host cells
portals of exit
what is pathogenicity
the ability to cause disease
what is virulence
the degree of pathogenicity
what are the three portals of entry
mucous membrane
skin
parenteral route
what is meant by parental route
deposited directly into tissues when barriers are penetrated
what is ID50? what does it measure
infectious dose for 50% of a sample population
measures virulence of a microbe
what is LD50? what does it measure
lethal dose for 50% of a sample population
measures potency of a microbe/toxin
what is adherence
when a pathogen attaches to a host tissue
how does the pathogen attach to the host cell
adhesins (ligands) on the pathogen bind to receptors on the host cells
what are the three ligands
glycocalyx
fimbriae
membrane proteins
microbes form …
biofilms
what is a biofilm
communities that share nutrients
what is a capsule made of
glycocalyx
what does capsules impair
phagocytosis
what are there components of the cell wall we should know
m protein
opa protein
waxy lipid
what does m protein resist
phagocytosis
what does the opa protein allow
attachment to host cells
what is the waxy lipid layer made of and what does it help resist
mycolic acid
digestion
what are coagulases
coagulate fibrinogen
what are kinases
digest fibrin clots
what are hyaluronidase
digests polysaccharides that hold cells together
what are collagenases
breaks down collagen
what are IgA proteases
destroy IgA antibodies (found in mucus membrane)
what is antigenic variation
pathogens alter their surface antigens
what are invasins
surface proteins produced by bacteria that rearrange actin filaments of the cytoskeleton
what does invasins cause
membrane ruffling
what do biofilms play a role in
evading phagocytes
biofilm bacteria are more resistant to …
phagocytosis and antibiotics
what are biofilm bacteria shielded by
extracellular polymeric substance of biofilm (EPS)
what are siderophores
proteins or molecules secreted by pathogens that bind iron more tightly than host cells
what molecule is required for most pathogenic bacteria
iron
what are the two consequences of siderophores
disrupts that host cell function
uses host cell nutrients
what are toxins
poisonous substances produced by microorganisms
what is toxigenicity
ability of a microorganism to produce a toxin
what is toxemia
presence of toxin in the host’s blood
what is intoxications
presence of toxin without microbial growth
what are exotoxins
proteins produced and secreted by bacteria
what are the two consequences of exotoxins
destroy host cells
inhibit metabolic functions
what are antitoxins
antibodies against specific exotoxins
what are toxoids
inactivated exotoxins used in vaccines
what are A-B toxins
contain an enzyme component (A part) and a binding component (B part)
inhibit protein synthesis
what are genotoxins
damage DNA by causing mutations, disrupting cell division and can lead to cancer
what are superantigens
cause an intense immune response due to release cytokines from host cells
cause symptoms of fever, nausea, vomiting, diarrhea, shock, and death
what are membrane-disrupting toxins
lyse host cells by disrupting plasma membranes
what are three membrane-disrupting toxins
leukocidins
hemolysins
streptolysins
endotoxins are only found in … bacteria
gram negative
what is the portion of lipopolysaccharides (LPS) of gram-negative bacteria
lipid A
what are plasmids
carry genes for toxins, production of antibiotics or resistance genes and other enzymes
what is lysogenic conversion
changes characteristics of microbe due to incorporation of a prophage
lysogenic conversion uses …
specialized transduction
what are two pathogen properties of viruses
cytopathic effects
alpha and beta interferons
what are cytopathic effects
visible effects of viral infections on a cell
what are alpha and beta interferons produced by and what do they protect
produced by virally-infected cells
protect neighboring cells from viral infection
what are the 5 portals of exit
respiratory tract
gastrointestinal tract
genitourinary tract
skin
blood
Note 
Flashcard (80)