p.2
Antibiotic Resistance Evolution
What are the two main mechanisms through which bacteria develop antibiotic resistance?
Mutations and natural selection.
p.14
Kirby Bauer Sensitivity Test
What does the Zone of Inhibition (ZI) indicate?
The effectiveness of the antibiotic against bacteria.
p.1
Mechanism of Action of Penicillin
What do antibiotics do?
Kill bacteria or impair their growth.
p.12
Kirby Bauer Sensitivity Test
What does the Kirby Bauer Sensitivity Test determine?
The sensitivity of microbes to antibiotics.
p.14
Kirby Bauer Sensitivity Test
How do you determine which antibiotic is most resistant?
Check the table in the book against the diameters you measure.
p.10
Impact of Antibiotic Overuse
What are two main factors that inflate antibiotic resistance?
Over-prescription of antibiotics and improper use of antibiotics (by patients and livestock).
p.1
Discovery of Antibiotics
What was the first natural antibiotic to be discovered?
Penicillium notatum (fungus).
p.1
Discovery of Antibiotics
Who discovered Penicillium notatum and when?
Alexander Fleming in 1928.
p.16
Antiseptics vs. Disinfectants
What are antiseptics?
Substances that kill or inhibit microbes (not endospores) and are gentle enough for use on the skin.
p.16
Antiseptics vs. Disinfectants
What are disinfectants?
Substances that kill or inhibit microbes and may kill spores, but are only for use on surfaces and objects.
p.7
Gene Transfer in Bacteria
What role does gene transfer play in antibiotic resistance?
Bacteria can transfer resistance genes to each other through processes like conjugation, transformation, and transduction.
p.13
Kirby Bauer Sensitivity Test
How is the colony picked up?
With a swab, then stirred into saline.
p.5
Natural Selection in Bacteria
What happens to a survivor in an environment with no competition?
The survivor reproduces and its population becomes antibiotic resistant.
p.5
Natural Selection in Bacteria
What is the outcome of natural selection in the context of antibiotic resistance?
The population becomes antibiotic resistant.
p.8
Impact of Antibiotic Overuse
Why are antibiotics given to livestock?
Antibiotics are given to livestock to promote growth and prevent disease.
p.8
Antibiotic Resistance Evolution
What is a major consequence of giving antibiotics to livestock?
It contributes to the development of antibiotic-resistant bacteria.
p.2
Antibiotic Resistance Evolution
How can bacteria evolve antibiotic resistance?
Through mutations and natural selection.
p.15
Kirby Bauer Sensitivity Test
What does a zone of inhibition smaller than 19mm around S. epidermidis indicate?
The bacteria are resistant to the antibiotic toadicilin.
p.15
Kirby Bauer Sensitivity Test
What does a zone of inhibition greater than 20mm around S. epidermidis indicate?
The bacteria are sensitive to the antibiotic toadicilin.
p.14
Kirby Bauer Sensitivity Test
What should you measure around the antibiotic disc?
The diameter of the Zone of Inhibition (ZI).
p.12
Kirby Bauer Sensitivity Test
What are antimicrobials?
Compounds that kill or inhibit microbial growth.
p.15
Kirby Bauer Sensitivity Test
Do different species or families of bacteria have the same thresholds for resistance and sensitivity?
No, different species/families have different thresholds for resistance and sensitivity.
p.12
Kirby Bauer Sensitivity Test
What do antibiotics do?
Kill or inhibit the growth of bacteria.
p.17
Antiseptics vs. Disinfectants
What is the primary function of sanitizers?
Sanitizers reduce microbes to limits deemed acceptable by health and safety standards but do not eliminate all microbes.
p.9
Impact of Antibiotic Overuse
What is a potential consequence of continued overuse of antibiotics?
The creation of super resistant pathogens that we cannot kill.
p.12
Kirby Bauer Sensitivity Test
What do antifungal agents do?
Kill or inhibit the growth of fungi.
p.17
Bacteriostatic vs. Bactericidal Agents
What does a bacteriostatic agent do?
A bacteriostatic agent prevents new microbial growth but does not kill existing cells.
p.10
Antibiotic Resistance Evolution
What happens to resistant strains when exposed to antibiotics?
Resistant strains are not killed by antibiotics.
p.17
Bacteriostatic vs. Bactericidal Agents
What is the function of a bactericidal agent?
A bactericidal agent kills microbes.
p.10
Antibiotic Resistance Evolution
Can you name an example of a resistant strain?
MRSA (Methicillin-resistant Staphylococcus aureus).
p.11
Healthcare-Associated Infections
Why should you never open a plate with S. aureus?
Because it can be pathogenic and pose a health risk.
p.1
Mechanism of Action of Penicillin
How does penicillin inhibit bacterial growth?
By inhibiting peptidoglycan formation.
p.1
Mechanism of Action of Penicillin
Why can penicillin kill bacteria without harming human cells?
Because peptidoglycan, which penicillin inhibits, is a bacterial cell wall component not found in human cells.
p.18
Kirby Bauer Sensitivity Test
What type of plate is used in the experiment?
A nutrient agar (NA) plate.
p.18
Kirby Bauer Sensitivity Test
How should the bottom of the plate be labeled?
With 4 circles where you will place discs.
p.18
Kirby Bauer Sensitivity Test
How should the plates be kept to ensure the discs don't fall?
Keep the plates right side up.
p.18
Kirby Bauer Sensitivity Test
At what temperature and for how long should the plates be incubated?
Incubate at 37°C for 24 hours.
p.16
Antiseptics vs. Disinfectants
Can antiseptics be used on the skin?
Yes, they are gentle enough for use on the skin.
p.11
Antiseptics vs. Disinfectants
Which bacteria does not ferment mannitol on MSA?
Staphylococcus epidermidis.
p.10
Healthcare-Associated Infections
Where are many resistant strains commonly found?
Many resistant strains are nosocomial or healthcare-associated infections (HAI).
p.18
Antiseptics vs. Disinfectants
What should be done with the discs before placing them on the plates?
Impregnate the discs in antiseptics/disinfectants.
p.7
Impact of Antibiotic Overuse
Why is the overuse of antibiotics a concern?
Overuse of antibiotics can lead to antibiotic resistance, making infections harder to treat.
p.4
Antibiotic Resistance Evolution
What is the significance of a bacterium with better defense mechanisms?
It is more likely to survive antibiotic treatment.
p.13
Kirby Bauer Sensitivity Test
Why is Mueller-Hinton agar used instead of Nutrient Agar (NA)?
Because it is more permeable than NA.
p.6
Gene Transfer in Bacteria
How can bacteria pass along defenses?
Through gene transfer, specifically plasmid transfer.
p.7
Natural Selection in Bacteria
How does natural selection contribute to antibiotic resistance?
Bacteria with mutations that confer resistance are more likely to survive and reproduce, passing on the resistant traits to future generations.
p.7
Healthcare-Associated Infections
What are healthcare-associated infections (HAIs) and their relation to antibiotic resistance?
HAIs are infections patients acquire while receiving treatment for other conditions in a healthcare setting, often involving antibiotic-resistant bacteria.
p.13
Kirby Bauer Sensitivity Test
What is done after creating the lawn on the agar plate?
Antibiotics are dispensed.
p.16
Antiseptics vs. Disinfectants
Give examples of common antiseptics.
Hydrogen peroxide, iodine, alcohol.
p.16
Antiseptics vs. Disinfectants
Can disinfectants be used on the skin?
No, they are only for use on surfaces and objects.
p.7
Antibiotic Resistance Evolution
What is antibiotic resistance?
Antibiotic resistance occurs when bacteria evolve to survive exposure to antibiotics that would normally kill them or stop their growth.
p.16
Antiseptics vs. Disinfectants
Give examples of common disinfectants.
Bleach, formaldehyde, phenol.
p.13
Kirby Bauer Sensitivity Test
From which plate is a colony being chosen?
From an S. epidermidis plate.
p.4
Mechanism of Action of Penicillin
What is the primary action of antibiotics?
Antibiotics kill bacteria.
p.13
Kirby Bauer Sensitivity Test
How is the lawn created on the agar plate?
By streaking the plate in 3 directions using 1 cotton swab.
p.13
Kirby Bauer Sensitivity Test
What type of agar plate is being labeled today?
A Mueller-Hinton agar plate.
