Lecture 3 - An Infection Model Flashcards
What is the difference between gram positive and gram negative bacteria?
Gram + have thicker peptidoglycan wall
Gram + bacteria have no outer lipid membrane whereas gram - bacteria do
What is meant by normal flora or the micro biome?
The microorganisms that are normally present in/on the body
What are some gram positive cocci bacteria which are part of the normal flora of the skin?
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus species
What are some Gram positive bacilli bacteria part of the normal flora of the skin?
Corynebacterium species
Propioibacterium acne’s
What colour do gram positive bacteria stain?
Purple/violet
Why do gram positive bacteria stain purple?
Their thick peptidoglycan wall retains the crystal violet stain
What colour do gram negative bacteria stain?
Red
Why do gram negative bacteria stain red?
Their thin peptidoglycan walls cannot retain the stain
What causes cellulitis?
Infection caused by bacteria that are part of the normal skins micro biome
What microorganism commonly causes Thrush?
Candida albicans
Which bacterial microbe is important in controlling the levels of Candida albicans?
Lactobacillus bacteria
How do Lactobacilli keep number of Candida albicans under control preventing thrush from developing?
Maintain the acidic pH around the genitals in women preventing the overgrowth of Candida albicans
What type of microbe is Streptococcus mutans?
Gram + cocci
Where are Streptococcus mutans normally found?
Oral cavity
High in saliva
Surface of enamel
How do Streptococcus mutans cause infection?
Use glucose and sucros (fermentable carbs) to build their capsule.
They attach to the enamel and digest the enamel
What type of microbe is Streptococcus pneumonia?
Gram positive cocci
Where are Streptococcus normally found?
Mucus layer overlying epithelial surface of the upper respiratory tract
How does Streptococcus pneumonia cause infection?
Directly invades endothelial cells of the upper/middle respiratory tract
What type of microbe is Escherichia coli (E.coli)?
Gram negative bacillus
Where is Escherichia coli normally found?
Lower intestine
How does Escherichia coli cause infection?
What is the method of infection?
How does the infection produce symptoms?
When orally ingested travels down digestive tract releasing the Shiga toxin with damages lining of small intestine
What type of microbe is Candida albicans?
Gram + fungi/yeast
Where is Candida albicans normally found?
Skin
Mouth
Gut
Vagina
How does Candida albicans cause infection?
Infection is when it overgrows Orr enters deep into the body
Hyphae breach mucosal surface and damage underlying tissues
