Module 4 Flashcards
what are growth phases of bacteria
lag phase:
-bacteria are acclimating to their environment, little to no growth occurs
Log or exponential growth phase:
-linear, log/exponential growth where rapid growth and division of bacteria occurs
Stationary phase:
-Rate of growth roughly equals rate of death, nutrients are less abundant
death/logarithmic decline phase:
-Cell death exceeds cell division, lack of nutrients
What are turbidity estimates
Total cell counts: live and dead
-For E. coli, Abs of 1.0 A600 = 1x10^9 cfu/mL
What is serial dilution counting
How to calculate:
-Start with colony count
-Divide by the volume plated (this gives cfu/mL of the tube used)
-Multiply by volume of tube (this gives total cfu in tube)
-Divide by volume placed in that tube from the previous (this gives cfu/mL of previous tube, then multiply by volume of tube to obtain total cfu)
What is counting chamber
Remember mm^3 is equal to microlitres!! must convert if answer requires mL
Describe the killing of bacteria
-Antibiotic: selectively kills bacteria preserving host
-Bactericidal: kills bacteria
-Bacteriolytic: bursting a cell open and killing
-Bacteriostatic: population number is not going up
-Mechanism of action: target way it kills
-Spectrum of activity: (narrow/broad)
-Effective dose:
-Toxic dose
-Therapeutic Index (T/E): toxic/effective dose
-Natural/semi-synthetic/synthetic
Describe cell wall inhibiting antibiotics
bacteriolytic
Describe protein synthesis inhibiting antibiotics
bacteriostatic
Describe plasma membrane damaging antibiotics
Describe nucleic acid synthesis inhibiting antibiotics
Describe metabolic inhibiting antibiotics
what is sensitivity testing
Describe antibiotic resistance
What are the modes of antibiotic resistance?
Describe the spread of antibiotic resistance
How can we prevent antibiotic resistance
