Chapter 15: Mechanisms of Pathogencitiy Flashcards
What are 3 examples of portal of entry
- mucous membrane
- skin
- parental route
Examples of the parental route
- infection sites
- wounds
- insect bites
what kind of organism can enter through the skin
staphylococcus
where are mucous membranes in the human body
- respiratory tract (TB)
- GI tract
- GU tract (STD)
- conjunctiva (measles)
what is the easiest poratl of entry
respitory tact
exoenzymes produce
toxins
toxin definition
substances that contribute to pathogenicity
Toxigenicity definition
ability to produce a toxin
Toxemia definition
presence of toxin in the hosts blood
toxoid defintion
inactivated taxin used in a vaccine
antitoxin defintion
antibodies against a specific toxin
characteristics od exoenzymes
- coagulase
- kinase
- hyaluronidase
- collagenase
coagulase
coagulates blood
fibrogen –> fibrin
example of organisms who use coagulase
s. aureus
kinase purpose
dissolves clots
examples of organism who use kinase
s. pyogenes
collagenase purpose
breaks down collagen
examples of organsims who use collagenase
c. perfriges (GANGREEN)
what does hyaluronidase do
blackens skin
examples of organsims who use hyaluronidase
- closterdium perfringes (gangreen)
- s. pyogenes
what are the two types of toxins
- exotoxin
- endotoxin
exotoxin is produced by
mostly gram positive bacteria
- produced as a part of growth
endotoxin is produced by
gram negative bacteria
- lipid A
exotoxins produce ______ sings / symptoms
specific
endotoxins produce ______ signs / symptoms
general
exotoxins are ______ in nature
protein
exotoxins are neutralized by
Ig antibodies (antitoxins)
example of a toxiod
DTap vaccine
what are general symptoms
- fever
- GI tract: nausea, vomiting, diaheaa / dysentery
- shock
are antibodies produced in responce to endotoxins
no
shock pathway
phagocytosis –> triggers Tumor Necrosis Factor or Cachetin –> released to the blood –> vital organs –> impense drops in blood pressure –> organs shut down
fever pathway
phagocytosis –> destroy and digest –> lysosomes release enzymes –> release IPS –> release cytokines –> interlukin (IL-1), called: endogenous pyrogens –> circulates –> reaches hypothalamus –> prostaglandin released –> resets temp –> fever
- chills ( increased IL-1, shivers)
OR - Crisis (decreased IL-1, sweating)
what are the three classes of exotoxins
- classic AB
- membrane disrupting
- Superantigens
what are the four examples of classic A+B
- C. diphteriae
- Botulinum toxin
- tetanopasmin
- vibriotoxin
C. dipteriae
B =binds
A = shuts down protein synthesis –> causes symptoms –> forms psedomembrane
Botulium toxin
B = binds
A = blocks neuromuscular junction –> no acetylcholine released –> result: flaccid acid
Tetroplasmin
B = binds
A = blocks GABA at the neuromuscular junction –> spasms 1. lockjaw 2. opithotenas 3. cardiovascular / respitory
GABA is responsiable for
relaxation
membrane disrupting
- tries to break phospholipid bilayer
- cellular components leak out
OR - make protein channels
process of membrane disrupting
- hemolysin
- leukocidin
- erythrogenic
–> scarlet fever –> red skin rash (breakage of blood vessels)
Superantigens
- prokokes immune responce
- releases cytokines
release of cytokines
interlukins –> circulate –> warning in vital sings –> affecs GI tract –> symtoms: nausea, vomitting, diarrhea
example of superantigens
s. aureus
- TSS
- Food posioning
vibrotoxin
B=binds
A = Gi tract cells –>convert to pumps –>triggers cAMP second system –>rice water stool
adherence
- establishes infection
- forms route for invasion
how does a caspule influence pathogenicity
- evades phagocytosis
example of adherence
s. mutans
s. mutans
uses capsule + enzyme glucosyltransferase digests sugar (sucrose) – > converts to:
1. glucose –> enzyme –> glucon –> plaque
2. fractose –> enzyme –> forms acid –> degenerates tooth structure
flucon
gummy thin polysaccaride
roles of the host
- provides receptors (plasma membrane) –> sugars –> mannose, fructose
roles of the pathogen
- has adhesions –> glycoproteins or lipoproteins –> on capsule, flagella, fibrae, M protein, mycolic acid, opa proteins
opa proteins are found on
neisseria gonnorhea
example of M proteins
s. pyogenes
M proteins
- heat and acid resistant
- used for attatchement
- evades phagocytosis
example of glycocalyx
caspule
streptococcus mutans
example of fimbrae
escherichia coli
pathogenicity
the ability to cause disease
virulence
the extent of pathogencicty