Unit 3: K43a.Intro To ABX

Question 1

What kind of cells comprise humans?

Answer 1

Eukaryotes

Question 2

What kind of cells comprise bacteria?

Answer 2

Prokaryotes

Question 3

Where can one find the genetic material in bacteria?

Answer 3

In the nucleoid, a tangle of genetic material

Question 4

TRUE or FALSE: bacteria have a nucleus

Answer 4

False

Question 5

Eukaryote or prokaryote: parasites

Answer 5

Eukaryote

Question 6

Eukaryote or prokaryote: fungi

Answer 6

Eukaryote

Question 7

Eukaryote or prokaryote: viruses

Answer 7

Prokaryote

Question 8

Eukaryote or prokaryote: bacteria

Answer 8

Prokaryote

Question 9

Why does it matter if a microbe is a eukaryote or prokaryote?

Answer 9

We need to know if the antimicrobial used can also damage human cells

Question 10

After gram staining, what color are

1. GRAM + cells?
2. GRAM - cells?

Answer 10

1. Purple

2. Pink

Question 11

What is the peptidoglycan later, and what difference does it make in gram + vs gram - bacteria?

Answer 11

Peptidoglycan is a layer surrounding a bacterium. In gram +, it is THICK. In gram -, it is THIN. The peptidoglycan holds the color for the gram stain.

Question 12

What is the difference between AEROBIC and ANAEROBIC bacteria?

Answer 12

Aerobic bacteria need oxygen.

Anaerobic bacteria do not need oxygen.

Question 13

What are the names for anaerobic bacteria that

1. can use oxygen
2. will die if exposed to oxygen?

Answer 13

1. Facultative anaerobes

2. Obligate anaerobes

Question 14

Aerobic bacteria are further classified into what?

Answer 14

Glucose fermenters vs non glucose fermenters

Question 15

What is a fastidious organism?

Answer 15

Only grows in particular things

Think: the friend you invite to dinner but will only eat certain foods in certain places

Question 16

Explain MIC

Answer 16

Minimum Inhibitory Concentration: lowest concentration needed to inhibit growth of bacteria

Question 17

Define MBC

Answer 17

Minimum Bactericidal Concentration: lowest concentration of an antibiotic that will kill bacteria

Question 18

Bacteriostatic vs Bactericidal

Answer 18

Bacteriostatic: prevents bacterial growth

Bactericidal: kills bacteria by attacking the cell wall

Question 19

Reason to give bacteriostatic antibiotics…

Answer 19

Does not kill. Just inhibits. Decreases bacterial load so person’s immune system can eliminate infection.

RISK: organism can regrow when medication stopped

Question 20

Reasons to give bactericical antibiotics…

Answer 20

Attacks cell wall to kill bacteria. Given for serious situations:
—severe/dangerous infections: endocarditis, meningitis, osteomyelitis
—infection in an immunocompromised patient

Question 21

Bactericidal meds can be _____ dependent or _____ dependent. Need to know this because…

Answer 21

Concentration
Time
Affects how they are dosed

Question 22

What does the MIC mean for time-dependent dosing?

Answer 22

Therapeutic effect only happens when the concentration is above MIC. When the concentration drops below MIC, it is time for another dose.

Question 23

Name some classic time-dependent Bactericidal antibiotics

Answer 23

Beta-Lactams
Tetracyclines
Linezolid

Question 24

Name some classic concentration dependent antibiotics

Answer 24

vancomycin
Aminoglycosides
Gentamicin

Question 25

Gentamicin toxicities:

Answer 25

Nephrotocicity

Ototoxicity

Question 26

What does the MIC mean for concentration-dependent dosing?

Answer 26

Cmax/MIC (aminoglycosides)

OR

AUC/MIC (vancomycin)

**administering large doses on an intermittent basis will maximize effect

Question 27

Define NARROW SPECTRUM

Answer 27

Treats a very specific or a few specific bacteria. Doesn’t kill other bacteria unnecessarily.

Question 28

Define BROAD SPECTRUM

Answer 28

Works for a large variety of bacteria prior to identification of specific organism (e.g. sepsis protocol)

Question 29

Define EXTENDED SPECTRUM

Answer 29

A child medication that is chemically modified from the narrow spectrum parent. New child med is effective against more bacteria than the parent med.

Question 30

Major risk of broad spectrum antibiotics

Answer 30

Superinfection

Question 31

Criteria for ABX selection

Answer 31

— C and S results (takes a few days)
— Host status (allergies, age, pregnancy, site of infection, etc)
— drug factors (pharmacokinetics, cost, toxicity, resistance)

Question 32

Definitive antibiotic treatment

Answer 32

We know exactly what we’re treating

Question 33

Empiric ABX treatment

Answer 33

Using an antibiotic that is effective for organism that typically causes that specific infection (e.g. nitrofurantoin for uncomplicated UTI)

Question 34

Prophylactic ABX treatment

Answer 34

To prevent infection

i.e. valacyclovir daily to prevent HSV outbreak

Question 35

Mechanisms of microbe resistance

Answer 35

— decreased bacterial cell permeability (unable to enter bacteria)
— enzymatic modifications (e.g. bacteria make enzymes that destroy antibiotic)
— alterations on target site
— active efflux: bacterial cell pumps antibiotic back out of cell

Question 36

ESKAPE pathogens: explain why they’re a concern and name them

Answer 36

High resistance. Limited treatment options.

Enterococcus faecium 
Staphylococcus aureus
Klebsiella pneumoniae 
Acinetobacter baumannii 
Pseudomonas aeruginosa
Enterobacter species

Question 37

1 duty in prescribing antibiotics

Answer 37

Prevent resistance

Question 38

How to prescribe the prevent resistance

Answer 38

Limit antibiotic use
Avoid using antibiotics for colonization
Adding most narrow spectrum agent that you can
Use correct dose
Use correct duration of therapy (shortest possible)

Question 39

MBC:MIC > 4

Answer 39

Bacteriostatic

Question 40

MBC:MIC <= 4

Answer 40

Bactericidal

Question 41

Bacteriostatic or Bactericidal?

Tetracyclines

Answer 41

Bacteriostatic

Question 42

Bacteriostatic or Bactericidal?

Beta Lactams

Answer 42

Bacteriostatic

Question 43

Bacteriostatic or Bactericidal?

Vancomycin

Answer 43

Bactericidal

Question 44

Bacteriostatic or Bactericidal?

Sulfonamides

Answer 44

Bacteriostatic