Labs

Question 1

What is hemolysis?

Answer 1

Bacteria’s ability to lyse RBC

Question 2

How is hemolysis used to identify bacteria?

Answer 2

It is based on how ‘see thru’ the hemolysis is from the bacteria

Question 3

What does alpha hemolysis look like?

Answer 3

Partial disruption of RBC by bacteria results. It may have a greenish hue

Question 4

What does beta hemolysis look like?

Answer 4

Bacteria secrete enzymes that eliminate the RBC, creating this clear look

Question 5

What does gamma hemolysis look like?

Answer 5

It does not affect the RBC so there is no change

Question 6

What does delta hemolysis look like?

Answer 6

It creates a ‘double hemolysis’

Question 7

What do we use for antiB sensitivity testing?

Answer 7

Mueller-Hinton agar plate

Question 8

Why should you use the chart to interpret the size of the zone of inhibition?

Answer 8

The size does not determine which antiB is best. So, you need to use the chart to determine which will work best.

Question 9

What is the significance of spores?

Answer 9

THey are resistant to heat, desiccation, chemicals, radiation, and other harsh environmental elements.
Spores may help protect bacteria so it can stay alive in this “dormant” phase (ex: lepto in dried puddle that then rehydrates)

Question 10

What disease does Clostridium tetani cause? Name and symptoms

Answer 10

Tetanus
Lock-jaw, fever, stiff muscles

Question 11

Who is affected by tetanus?

Answer 11

Carnivores, pigs, cattle, & horses

Question 12

What disease does B. burgdorferi cause? Name and symptoms

Answer 12

Lyme disease
Stiffness, rash

Question 13

What animals are affected by Lyme disease?

Answer 13

Dogs, cats, horses, cattle

Question 14

How is Lyme disease contracted?

Answer 14

Ticks!

Question 15

Testing w a DTM jar, how should the sample be placed? How should the lid be secured on? Why?

Answer 15

1. On top of the medium
2. Lid should be lightly screwed on
3. This is so it can ‘breathe’ but not escape

Question 16

What color change occurs if dermatophyte grows?

Answer 16

Red

Question 17

Max no of days you should observe bottle/plate for growth w a DTM sample?

Answer 17

7 to 10 days. Check it daily

Question 18

What can cause positive color reactions on DTM besides dermatophytes?

Answer 18

Contaminates & non pathogenic fungi

Question 19

most common dermatophyte identifies on canine/feline species?

Answer 19

Ringworm AKA M. canis

Question 20

A positive DTM plate should look like…

Answer 20

Red in color

Question 21

How long should a wood’s lamp warm up for?

Answer 21

5min

Question 22

What should the woods lamp detect on a positive patient?

Answer 22

Hyphae in hair shafts

Question 23

T/F: All dermatophytes will fluoresce under a woods lamp

Answer 23

False! Only 50% will

Question 24

What is the common name for Microsporum canis?

Answer 24

Ringworm

Question 25

What is a Microsporum?

Answer 25

A genus of fungi & type of fungi imperfecta

Question 26

Purpose of crystal violet?

Answer 26

To stain G+ by retaining dye on the thick peptidoglycan

Question 27

Purpose of Iodine?

Answer 27

Acts as a mordant (glue) to adhere crystal violet stain to G+ bacteria

Question 28

Purpose of alcohol/ethanol?

Answer 28

Decolorizer & will dissolve outer membrane of G- cells

Question 29

Purpose of Safrorin?

Answer 29

Stains G- bacteria pink/red

Question 30

What type of media is blood agar?

Answer 30

Enriched!

Question 31

What is it called if a patient contracts an infection of a sort from the hospital?

Answer 31

Nosocomial

Question 32

What is the mechanism of action for Chlorhexidine?

Answer 32

Disrupts cell membranes

Question 33

Name two pathogenic bacteria that can produce endospores.

Answer 33

1. Bacillus
2. Clostridium

Question 34

What is the significance of endospores? How do they specifically benefit the bacteria?

Answer 34

1. Endospores produce bacteria/toxins
2. This makes it very difficult to treat and decontaminate

Question 35

Name two reasons to heat fix smears on a microscope slide before gram staining.

Answer 35

1. Kills bacteria
2. Protects/preserves cell morphology (shape)

Question 36

What is the goal of the four-quadrant streaking pattern? (2)

Answer 36

1. Spread out the colonies
2. Isolate the colonies