December 2 notes

December 2, 2009
Host pathogen interactions:

g. Invasive disease – infections are caused by microorganisms that in a normally healthy person are considered a sterile site
- infectious disease where symptoms b/c of microbes growing in what, a healthy host is a sterile site
Ex. Your heart is not open to the outside world so heart and blood are a sterile site in a healthy person (lungs are not sterile)
h. Invasion factors- (subcategory of virulence factors) chemicals produced by microbes that cause disease / microbes that cause disease
chemicals produced by pathogens that allow those pathogens to get into normally sterile tissue (such as blood cerebrospinal fluid or muscle)

Toxigenic disease: Microbes growing in normally not- sterile site, producing “toxin” that results in symptoms in the host
- It is the production of the toxin protein that causes symptoms in the host
- Ex. Toxic shock syndrome – staph aureus can produce a protein called toxic shock syndrome toxin 1 TSST-1 in an aerobic environment which kicks system into overdrive (not an example of an invasive disease but an example of toxigenic disease.
I Exotoxin: Protein expressed by actively- growing bacteria, which contributes to symptoms in a host ex. TSS
ii) endotoxin= lipid A component of LPS
i) C. botulinum: like other clostridia sp.
a. Strict anaerobes
b. Spore forming
i. Spore very durable suspended animation state of bacteria
c. Reservoir is the soil
ii) Actively growing C. botulinum expresses botulism toxin by active toxin ( protein that has
a. Botulism toxin- the most toxic substance on planet earth
i. Deadly does: 1ng/ kg weight or the person
ii. Kills persons by paralyzing the diaphragm muscle
1. Death from suffocation botox disables motor neurons, incl. those that control diaphragm the person in turn cannot breath
b. Botulism food poisoning:
i. Prepping of canning food would create an anaerobic environment in the jar of canned vegetables for example
ii. This canning would allow for the germination of live spores and grow into live bacteria
iii. Spores then express botox gene
1. Lots of botox in jar
2. Safe way would be to heat the vegetables before hand and therefore heating them denatures the protein
c. Infant botulism and normal flora: human gut is non sterile, anaerobic
i. C. botulinum spores in soil, elsewhere
ii. Normal flora prevents the botulism spores from having a place to go so they will pass through the system
1. Gut is a good place for C. botulinum to grow except that, in a healthy adult, normal flora fills spots for C. botulinum to grow
2. Infants do not have a lot of normal flora yet their gut is still sterile for the most part so infants should not consume honey (botulism spores are in honey) floppy baby syndrome

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License