Ocular Health

Question 1

Pathogenic

Answer 1

Something that can cause disease

Question 2

Why do we need basic knowledge of microbiology?

Answer 2

To help protect the vulnerable (weak, hospital px), avoid iatrogenic infection caused through medical exam or treatment)

Question 3

Bacteria are…

Answer 3

Prokaryotes - DNA is not enclosed in a nucleus

Question 4

Eubacteria

Answer 4

Have a peptidoglycan wall

Question 5

Archaebacteria

Answer 5

No peptidoglycan wall

Question 6

Gram Positive

Answer 6

Multi layered cell wall
Cause majority eye diseases
very thick peptidoglycan wall
end in cocci or coccus

Question 7

Gram Negative

Answer 7

Single layer cell wall
CL disease related
very thin peptidoglycan wall, but many layers

Question 8

Gram Stain Technique

Answer 8

1. Wash bacteria in a petri dish with crystal violet for 30s.
2. Wash it off
3. Add iodine solution and leave for 1 min
4. Add organic solvent (acetone/ethanol) and leave for 15s
5. Add counterstain (safranin) and leave for 30s

Question 9

Result for Gram Positive Bacteria

Answer 9

Lower permeability (thick wall) to organic solvent – retain the crystal violet and appear purple or blue - solvent doesn’t go through, crystal violet doesn’t wash off

Question 10

Result for Gram Negative Bacteria

Answer 10

Increased permeability (thin wall) to organic solvent and therefore absorb the counter stain and appear pink - crystal violet washes off, they absorb the counter stain