Download Control of Microbial Growth

Control of Microbial Growth
Chemical and
Chemotherapeutic Agents
Chemical Control
 MH (one per group)
 Culture
 Pick one of 2
 Coordinate with other table
A
C
 Quadrants
 Label for solutions
 (A, B, C, D)
 Label bacteria used
B
D
 Swab
 Confluent growth streak
 Rotate 90°
 Filter Disk
 Dip in proper solution
 Place in appropriate quad
 Repeat for all 4 quads
Chemotherapeutic Agents
 MH agar plate
 Group: Pairs
 Swab
 Confluent
 2x (90°)
 AB discs
dispenser
seat discs
Chemical Agents MOA
 Isopropranol
 H2O2
 Clorox
 Lab cleaner
 Other
Lysol
Betadine
Chlorhexidine
 Denature, dissolve PM
 Oxidative decarboxylation
 Oxidation
 Denature, dissolve PM
 Others
Denature, dissolve PM
Oxidation
Disrupts plasma membranes
Minimum Inhibitory Concentration
MIC
KB: measurements
Results
 Zones of inhibition
Measure diameter
Units: mm
 Results
Table of MIC
Interpretation
 Susceptible
 Intermediate
 Resistant
Chemotherapeutic Agents MOA
 Naldixic acid
 TMPS
 Gentamycin
 Vancomycin
 Penicillin
 Sulfisoxazole
 Tetracycline
 Azithromycin
 Inhibit DNA gyrase
 Inhibit Folic acid synthesis
 30S binding/interferes with
mRNA
 Inhibit cell wall synthesis
 Inhibit cell wall synthesis
 PABA analog, blocks folic acid
 30S binding/interferes with
tRNA
 50S binding/ prevents protein
elongation
Additive and Synergistic Effects of AB
 Combination Therapy
Reduce resistance
Lower dosage
Enhance activity
 Results
Zones of inhibition
 Effects
Additive
Synergistic