Lecture 3-Diagnostic Microbiology

Question 1

What factors decide what culture will be used with a specific organism

Answer 1

1) source of sample tested
2) species suspected to be present in sample
3) nutritional requirements for said species

Question 2

How are cultureS preserved?

Answer 2

By freezing them or keeping cold
Lyophilizer is fancy fridge name

Question 3

Three steps of staining identification

Answer 3

1. Make a smear
2. Fix dried smear with heat
3. Stain with desired dye

Question 4

What is the simple staining method

Answer 4

Single dye normally used
All organisms same colour
Size, shape, number, arrangement

Question 5

What is differential staining

Answer 5

Occurs when 2 different stains are used to differentiate two different types or parts of cells

Question 6

What is the difference between grams negative and gram positive bacteria

Answer 6

.gram positive has a smooth cell wall with a large ration of petidoglycan whereas, gram positive has small ratio of peptidoglycan (smal’line) and ribbed cell wall

Question 7

What are 3 other ways of staining

Answer 7

Flagella staining
Endosperm staining
Capsule staining

Question 8

What is fluorescence microscopy

Answer 8

Dye fluoresces at specific wavelength, tagged antibodies

Question 9

What is electron microscopy

Answer 9

Uses election beam rather then light) very precise

Question 10

What 2 aspects are important when studying morphology in detail

Answer 10

1. Absence or precense of certain traits help with identification
2. Morphology( structure) impacts physiology and pathogenicity

Question 11

What does morphology help science with/it’s use

Answer 11

I. Morphology helps to classify and identify (gram stain)
2. Gives clues to how cocci /bacteria behave in environment C capsules/endospores for example

Question 12

What are some characteristics of bacteria

Answer 12

‘1. Small 2. Fast metabolism 3. Easter growth

Question 13

What are the 3 basic shapes of bacteria

Answer 13

1. Spherical (cocci)
2. Red shaped (bacillus)
3. Spiral (spirilum)

Question 14

Define: chemically defined

Answer 14

All the chemical components are know in A growth

Question 15

Define: chemicaly undefined

Answer 15

’ When components can’t be controlled or are unknown

Question 16

Define enrichment media

Answer 16

Specific increase in a specific species of bacteria, isolate and multiply

Question 17

Define psychrophiles

Answer 17

.bacteria that grows best between 15to20°C

Question 18

Define mesophiles

Answer 18

Grow 25 to 40°C
Most bacteria belong here

Question 19

Define hermophiles

Answer 19

40 to 85°C

Question 20

Define aerobic micro organisms

Answer 20

-grow at normal atmospheric levels of oxygen

Question 21

Define anaerobic microorganism

Answer 21

. Cannot live in conditions containing oxygen

Question 22

Facultative microorganism define

Answer 22

Grow in aerobic and anaerobic conditions

Question 23

Micro aerophillic organism

Answer 23

( Can use oxygen for chemical reaction

Question 24

What is intracellular pH?

Answer 24

7.5

Question 25

What are other factors that influence bacteria growth

Answer 25

. pH, water, osmotic pressure