Notes 12/2

a. Invasive disease
i. Any infectious disease where the problems are caused by microorganisms living in what normally, in a healthy person, is a sterile sight
1. Ex. Heart, Blood, Muscle, CSF
ii. Invasion factors
1. Chemicals produced by pathogens that allow those pathogens to get into normally sterile tissue
b. Toxigenic disease
i. Disease caused by microorganisms growing in a normally non-sterile site, producing “toxin” that → symptoms in a host
1. Ex. S. aureus makes TSST-1
ii. Exotoxin
1. Protein that is expressed by actively growing bacteria → symptoms in a host
a. TSST-1
iii. Endotoxin = lipid A of LPS
1. Not secreted by actively growing bacteria – just part of gram (-) outer membrane, only being released if the bacteria dies
II. Two examples of toxigenic bacterial diseases
a. Botulism
i. Clostridium botulinum (like other clostridia sp.)
1. Strict anaerobes
2. Spore-forming
a. Spores – very sturdy, non-metabolic, suspended animation bacteria
b. When in a favorable environment they will germinate and grow – expressing the botulism toxic gene
3. Reservoir – Soil
ii. Botulism toxin
1. When Clostridium botulinum is actively growing it expresses botulism toxin
a. Protein that causes symptoms in us when we have it inside of us
2. Deadly dose: 1ng/kg weight of a person
3. Death from suffocation: BoTox disables motor neurons, including those that control diaphragm → can’t breathe
iii. Botulism food poisoning
1. In home canned foods – Used to – have stray botulism spores on the vegetables. The prepping of the food would take all of the oxygen out of the can creating an anaerobic environment – allowing for germination of botulism spores (grow into active bacteria)
a. When they grow actively they express the botulism toxin protein – most toxic substance known to man-kind
2. Don’t have to ingest the bacteria to get sick – just ingesting the toxin is enough
iv. Infant botulism and normal flora
1. Human body has lots of normally non-sterile sights that are anaerobic
a. Ex. Gut
2. C. botulinum spores in soil and many other places
3. Normal flora in the gut prevent the botulism spores from having anywhere to grow – they will just pass out of your system after they are eaten AS SPORES
a. The spaces that would be a good place for them to grow are already filled up with normal flora
4. In infants there is little normal flora to displace the bacteria – thus the bacteria grow and harm the baby greatly – baby can’t hold its own muscles up anymore ‘floppy-baby syndrome’

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