Intro to Antibiotics

Question 1

What is a broad spectrum antibiotic?

Answer 1

It is active against gram positive AND gram negative bacteria and it increases resistance.

Question 2

What is a narrow spectrum antibiotic?

Answer 2

It is active against gram positive OR gram negative.

Question 3

What does bactericidal mean?

Answer 3

• Kills bacteria

- Reasonably achievable tissue concentration that is greater than the minimum bactericidal concentration (MBC.)

Question 4

What does bacteriostatic mean?

Answer 4

• Stops growth or replication of bacteria

- Reasonably achievable tissue concentration that is greater than the minimal inhibitory concentration (MIC.)

Question 5

What do you need for a bacteriostatic drug to work?

Answer 5

You need a competent immune system.

Question 6

What does MIC stand for?

Answer 6

Minimal Inhibitory Concentration

Question 7

What does MBC stand for?

Answer 7

Minimum Bactericidal Concentration

Question 8

When are time-dependant antibiotics most effective?

Answer 8

When the level of drug remains above a certain cut-off for a significant portion of the day.

Question 9

T > MIC is greater than _____% of the dose interval?

Answer 9

40 - 50%

Question 10

When are concentration-dependant antibiotics most effective?

Answer 10

When a high leave of the drug is reached, often above an absolute cut-off. Does not need to be maintained for any specific amount of time.

Question 11

What does PAE stand for?

Answer 11

Post - Antibiotic Effect

Question 12

Concentration-dependant drugs have a ______ that causes continued organism suppression even after drug levels drop.

Answer 12

Post - Antibiotic Effect

Question 13

Cmax / MIC > ______?

Answer 13

8-12

Question 14

What is the “third - category” of dose - dependent drugs?

Answer 14

Some drugs have efficacy correlated with total body exposure to the drug (estimated by the AUC.)

AUC / MIC > 125

Question 15

What does AUC stand for?

Answer 15

Area Under the Curve

Question 16

What are the MOA of x-dependent drugs? (4)

Answer 16

1. Inhibition of cell wall synthesis
2. Disruption of cell membranes
3. Inhibition of protein synthesis
4. Inhibition of DNA synthesis / function

Question 17

Generally, drugs that inhibit the cell wall are low toxicity drugs. What drug is an exception?

Answer 17

Bacitracin. It is extremely nephrotoxic so it is only used topically.

Question 18

What are some B - lactam antibiotics?

Answer 18

Penicillins, Cephalosporins, Carbapenems and Monobactams, B - lactamase inhibitors.

Question 19

T/F: Drugs that inhibit cell wall synthesis require actively dividing bacteria and can be antagonized by antibiotics that inhibit protein synthesis.

Answer 19

True

Question 20

What is one category of drug that can be used to cause disruption of cell membranes?

Answer 20

Polymyxins

Question 21

Drugs that cause disruption of cell membranes are toxic, do not depend on bacterial replication and are rapidly _____ drugs.

Answer 21

Bactericidal

Question 22

T/F: Drugs that are used to inhibit protein synthesis all have the same level of toxicity.

Answer 22

False. Toxicity varies between drugs.

Question 23

Drugs that inhibit protein synthesis depend on __________ and are mainly bacteriostatic.

Answer 23

Bacterial replication

Question 24

What are some classes of drugs that inhibit protein synthesis as their MOA?

Answer 24

1. Aminoglycosides
2. Tetracyclines
3. Amphenicols
4. Macrolides/Lincosamides

Question 25

What are some classes of drugs that inhibit protein synthesis as their MOA?

Answer 25

1. Sulfonamides 2. Fluoroquinolones 3. Nitrofurans 4. Nitromidazoles 5. Rifampin 6. Novobiocin

Question 26

Drugs that are inhibitors of DNA synthesis and function can be ______ if they interfere with mammalian DNA.

Answer 26

Carcinogenic

Question 27

What class of drug causes nephrotoxicity (renal tubular epithelial cells, collecting ducts, and more distal tubular structures)?

Answer 27

Aminoglycosides

Question 28

What class of drug causes hepatotoxicity?

Answer 28

Tetracyclines sulfonamides

Question 29

What classes of drugs cause a neuromuscular blockade?

Answer 29

Aminoglycosides, Polymyxins, and Tetracyclines

Question 30

What class of drug causes ototoxicity?

Answer 30

Aminoglycosides

Question 31

Which drugs cause GI upset?

Answer 31

Ampicillin and Clindamycin

Question 32

Which drugs cause bone marrow toxicity?

Answer 32

Cloramphenicol and Sulfonamide

Question 33

Which drug is known for it's hypersensitivity reactions?

Answer 33

Penicillins

Question 34

What does resistance mean?

Answer 34

Bacterium is not inhibited or killed by concentrations of an antibiotic that would normally do so at concentrations that can be reached in the patient. ** Only use when necessary **

Question 35

What is extrinsic resistance? (3)

Answer 35

1. Drug does not reach the target site. 2. Drug is inactivated 3. Target is changed ** These mechanisms can affect a single antibiotic or an entire class of drugs. **

Question 36

What is intrinsic resistance?

Answer 36

Drug will never work against that class of bacteria because it does not possess the target structure (i.e. microbes with no cell wall resistant to penicillin) and does not exist in a favorable environment or antibiotic cannot get to site of action.

Question 37

What are the two categories of acquired resistance?

Answer 37

1. Chromosomal mutation | 2. Transferable drug resistance

Question 38

What is chromosomal mutation?

Answer 38

A form of acquired resistance that potentially occurs with increased sub-therapeutic exposure (non-transferable.)

Question 39

What is transferable drug resistance?

Answer 39

A form of acquired resistance where the resistant DNA is acquired from another bacterium.

Question 40

Transferable drug resistance has three different ways to acquire resistance. What are they?

Answer 40

Conjugation: passed from bacteria to bacteria Transduction: passed from virus to bacteria Transformation: plasmids are picked up by bacteria

Question 41

What is Biofilm?

Answer 41

Accumulation of microorganisms in which cells that are frequently embedded within a self-produced matrix of "slime" adhere to each other and/or a surface.

Question 42

Which bacteria maintains a biofilm?

Answer 42

Pseudomonas

Question 43

What organisms cause MRSA and MRSP in humans and dogs?

Answer 43

Humans: Staphylococcus aureus Dogs: Staphylococcus pseudointermedius

Question 44

T/F: Staph pseudointermedius is a big risk to healthy humans.

Answer 44

False. It only affects humans that are immunocompromised.

Question 45

What does decolonization mean?

Answer 45

Treating non-clinical carries of a bacteria with antibiotics.

Question 46

What species can you treat and recover from a bacteria without using decolonization?

Answer 46

Dogs