Download Effect of chemical and biological agents

Experiment 4
Effects of physical, chemical and biological
agents on bacteria
Outline
Moist heat
Bacteria
Culture media
Equipments
E.coli
B.subtitis
Broth
Water bath
UV
S.aureus
S.aureus
E.coli
Agar plates Agar plates
UV light
Reagents
Non
Chemical &biological
agents
Non
2% iodine
1% crystal violet
2% mercurochrome
garlic
paper disks of penicillin
paper disks of streptomycin
 Effect of moist heat
Bacteria
4 students / group
E.coil (liquid) (shake it)
Temperature
100℃
B.subtitis (slant)
RT
100℃
RT
Time
5min
30min
Control
5min
30min
Control
Tube number
1#
2#
3#
4#
5#
6#
Stand A
Stand A
Stand B
Stand B
Stand C
Stand C
 Effect of UV light
Condition：
expose UV light for 30min
Bacterial strain：
S.aureus
Inoculation method：Streak plate (with cotton stick)
mark
UV
UV 30min
 Effect of chemical and biological agents
Reagents:
1. 1% crystal violet
2. 2% mercurochrome
3. 2% iodine
4. garlic
5. paper disk of penicillin
Bring with me
tomorrow！
6. paper disk of streptomycin
Species：
S.aureus
E.coli
1 agar plate
1 agar plate
Mark
Manipulation
1
6
2
5
3
4
Observation of results
 Part 1. Effect of moist heat on bacteria;
E.coli, B.subtitis
 Part 2. Effect of UV light on bacteria;
S.aureus
 Part 3. Effect of chemical & biological agents on bacteria;
E.coli, S.aureus
Moist heat
 E.coli
1#: 100℃, 5min
2#: 100℃, 30min
3#: RT, Control
 B.subtitis
4#: 100℃, 5min
5#: 100℃, 30min
6#: RT, Control
Effect of moist heat on bacteria
Record:
Strains
100℃, 5 min
100℃, 30 min
Control
E. coli
B. subtitis
 Clear: “-” or bacterial growth: “+”
 Surface growing / Turbidity / Precipitate growing;
UV radiation
Describe result:
 Covered part
 Radiated part
UV
Effect of chemical and biological agents
 Measure inhibition zone
• diameter or 2 radius
Effect of chemical and biological
agents
Inhibition zone diameter (mm)
>15mm
10~15mm
<10mm
susceptibility degree
Extremely
sensitive
Medium
sensitive
Slight
sensitive
0mm
Resistant
Record:
Diameter of Inhibition Zone (mm)
Cultures
E.coli
S.aureus
Susceptibility
degree
1%
Crystal
violet
2%
Penicillin Streptomycin 2%Iodine
Mercurochrome
Garlic