Antimicrobials

Question 1

How can we control microbes?

Answer 1

• Sterilisation
• Disinfection
• Antimicrobial

Question 2

What is chemotherapy?

Answer 2

• Treatment of a disease with a chemical substance

Question 3

What is a antimicrobial?

Answer 3

• Chemical substance that kills or inhibits microorganisms

Question 4

What is a antibacterial?

Answer 4

• A chemical substance that inhibits bacteria

Question 5

What is an antibiotic?

Answer 5

• A chemical substance produced by a microorganism that inhibits bacteria

Question 6

What are the 4 principles when developing antibacterial agents?

Answer 6

• Safety
• Spectrum
• Absorption/distribution
• Resistance

Question 7

What pharmacological properties need to be considered when developing a drug?

Answer 7

• Active ingredients
• Formulation
• Lipophilicity
• Mode of action

Question 8

What is minimum inhibitory concentration (MIC)?

Answer 8

• Lowest concentration of a drug that prevents visible growth of bacteria
• The lower the concentration of drug, the more effective the antimicrobial

Question 9

What is a bacteriocidal?

Answer 9

• Kills bacteria

Question 10

What is a bacteriostatic?

Answer 10

• Prevents replication

Question 11

What are the 5 different modes of actions?

Answer 11

• Cell wall inhibitors
• Folate inhibitors
• DNA inhibitors
• Cell membrane disruptors
• Protein synthesis inhibitors

Question 12

What is the mode of action of cell wall inhibitors?

Answer 12

• Inhibits transpeptidase enzymes, which prevents cross bonds

Question 13

Name two examples of cell wall inhibitors

Answer 13

• Penicillins
• Cephalosporins

Question 14

What are penicillins?

Answer 14

• Divided into 6 groups
• Renal excretion
• Risk of hypersensitivity but generally safe
• Example: Synulox and Depocillin

Question 15

What are cephalosporins?

Answer 15

• Divided into four generations
• Better safety than penicillins
• Example: Convenia

Question 16

What is the mode of action of DNA inhibitors?

Answer 16

• Affects DNA/RNA

Question 17

Give 3 examples of DNA inhibitors

Answer 17

• Fluoroquinolones
• Nitroimidazoles
• Rifampin

Question 18

What are fluoroquinolones?

Answer 18

• Act on DNA gyrase to inhibit transcription
• Relatively safe but contraindicated in growing animals
• Example: Baytril

Question 19

What are nitroimidazoles?

Answer 19

• Damages DNA strands and prevents repair
• Relatively safe but neuro signs seen
• Example: Metrobactin

Question 20

What is rifampin?

Answer 20

• Inhibits RNA polymerase, which inhibits transcription
• Resistance can develop quickly
• No veterinary license, used on the cascade

Question 21

What is the mode of action of protein synthesis inhibitors?

Answer 21

• Targets prokaryotic ribosomes

Question 22

Give 6 examples of protein synthesis inhibitors

Answer 22

• Tetracyclines
• Chloramphenicols
• Aminoglycosides
• Macrolides
• Lincosamides
• Fusidic acid

Question 23

What are tetracyclines?

Answer 23

• Disrupt amino acid attachment at ribosomes
• Resistance seen
• Relatively safe
• Example: Ronaxan and Engemycin

Question 24

What are chloramphenicols?

Answer 24

• Prevents peptide bond formation
• Example: Nuflor

Question 25

What are aminoglycosides

Answer 25

• Distorts mRNA codes
• Ototoxic and nephrotoxic

Question 26

Give two examples of folate inhibitors

Answer 26

• Sulponamides
• Trimethoprim

Question 27

Give an example of a cell membrane inhibitor

Answer 27

• Polymixins

Question 28

What are good properties of an ideal antimicrobial?

Answer 28

• Good activity
• Readily absorbed
• Distributed to target site
• Resilient to resistance mechanisms
• Limited side effects and hypersensitivity