Key notes 2-16-2025

How does having a capsule effect the body?

It activates antiphagocytic and anticomplement activities

What happens when a bacteria has IgA proteases?

It cleaves IgA on mucous membrane

What is IgA?

Immunoglobulin A is found on the surface of mucous membrane that is the front line of protecting the body

• Cleaving this immunologlobin will allow the bacteria to take root in the body

What is LPS?

Lipopolysaccharide found in the outer wall of gram--negative bacteria

How many region does LPS have?

1) Antigenic O-specific polyusaccharide

2) Core polysaccharide

3) inner lipid A (aka endotoxin)

Why is LPS lipid A so important?

It is responsible for producing fever and shock condition in patientsW

What is the importance of the outer membrane functions?

1) Barrier to hydrophobic compounds

2) Acts as a sieve, allowing water-soluble molecules to enter via porins

3) Provides attachment sites to attach onto host cells

What is MacConkey agar selective for?

Gram negative organisms and lactose fermenters

What is Eosin-methylene blue (EMB) agar selective for?

Gram negative and between lactose / sucrose fermentation

What is Hektoen enteric (HE) agar selective for?

Gram-negative

Lactose and sucrose fermentation is a differential

• Orange color —> nonpathogen lactose & sucrose fermentors

• Green / blue and H2S gas —> Pathogens