6: Antimicrobial Agents

Question 1

Why is antibiotics resistance bad?

Answer 1

Because antibiotics are used in routine medical practice in primary and secondary care

Question 2

What is Antimicrobial Stewardship?

Answer 2

A systematic effort to educate + persuade antimicrobial prescribers to follow EVIDENCE-BASED prescribing

Question 3

What are the benefits of Antimicrobial Stewardship? (3 things)

Answer 3

1. Reduced Abx overuse
2. Reduce Abx resistance
3. Reduced Abx resistance developed @ an individual patient level AND community level

Question 4

Where does MRSA cause infections? (4 places)

Answer 4

1. Skin
2. Soft tissue
3. Bone
4. Blood

Question 5

Why is MRSA dangerous?

Answer 5

Develops resistance to new Abx quickly

Question 6

How are MRSA infections transmitted?

Answer 6

Direct contact from person to person

Question 7

What are the 2 types of MRSA infections?

Answer 7

1. CA-MRSA (Community Acquired)

2. HA-MRSA (Hospital Acquired

Question 8

What does CA-MRSA start as?

Answer 8

Skin infection

Question 9

What does HA-MRSA start as?

Answer 9

Skin / wound / surgical site infection

Question 10

What is the Pathogenesis of MRSA Infections?

Answer 10

1. S. aureus synthesises Penicillin-binding Protein 2a (PBP2a)
2. PBP2a has low affinity for Beta-lactams (produced by Abx)
3. This low affinity allows for transpeptidase activity and cell wall synthesis
4. This allows bacteria to grow and reproduce

Question 11

What does S. aureus synthesise?

Answer 11

Penicillin-Binding Protein 2a (PBP2a)

Question 12

What is special about PBP2a?

Answer 12

It has a low affinity for Beta-lactams

Question 13

What are Beta-lactams produced by?

Answer 13

Abx

Question 14

What does a low affinity for Beta-lactams allow?

Answer 14

Allows transpeptidase activity and cell wal synthesis –> allows bacteria to grow and reproduce

Question 15

How are MRSA infections managed? (5 things)

Answer 15

1. Healthcare professional + public education
2. Fast detection in the lab
3. Active surveillance
4. Patient isolation
5. Abx therapy

Question 16

What are the 2 Abx used for MRSA infections?

Answer 16

1. Glycopeptides (but expensive and toxic)

2. Flucloxacillin

Question 17

What does Clostridium difficile cause? (2 things)

Answer 17

1. Mucosal inflammation

2. Diarrhoea

Question 18

What is the pathogenesis of Clostridium difficile colitis?

Answer 18

Alteration of normal bacteria flora of the colon caused by Abx

Question 19

What is the management of Clostridium difficile?

Answer 19

Abx therapy but symptoms may reappear with prolonged Abx use –> so isolate the patient

Question 20

What is the difference between Bactericidal vs Bacteriostatic drugs?

Answer 20

Bactericidal: KILL target organism

Bacteriostatic: INHIBIT / DELAY bacteria growth / reproduction

Question 21

What is an example of a Bactericidal drug?

Answer 21

Penicillin

Question 22

What is an example of a Bacteriostatic drug?

Answer 22

Tetracycline

Question 23

Can some Abx be both Bactericidal and Bacteriostatic?

Answer 23

Yes

Question 24

What are the 6 Mechanisms of Action of antimicrobial agents?

Answer 24

1. Block pathogens Recognition / Attatchment to host
2. Inhibit Cell Wall Synthesis
3. Disrupt components of Cytoplasmic Membrane
4. Inhibit General Metabolic Pathways
5. Inhibit Protein Synthesis
6. Inhibit Nucleic Acid Synthesis

(learn dem from outside of cell to inside nucleus ygm)

Question 25

How does blocking pathogens Recognition / Attatchment to host work?

Answer 25

Stops virus from attaching to + entering the cell

Question 26

How does inhibiting Cell Wall Synthesis work?

Answer 26

Prevents peptidoglycan synthesis by preventing CROSS-LINKING of NAM subunits (N-acetyglucosamine n dem man)

Question 27

How does disrupting components of Cytoplasmic Membrane work?

Answer 27

Damages cell membrane --> causes leakage of important solutes needed for cell survival

Question 28

How does inhibiting Protein Synthesis work?

Answer 28

This targets Mitochondria Binds to subunits of ribosomes and disrupts protein metabolism

Question 29

How does inhibiting Nucleic Acid Synthesis work?

Answer 29

Interrupts DNA replication / RNA translation --> This inhibits bacterial multiplication + survival

Question 30

What are the 2 spectrums of action of Antimicrobial Agents?

Answer 30

1. Broad Spectrum | 2. Narrow Spectrum

Question 31

What organisms are Broad Spectrum agents used for?

Answer 31

Gram +ve and -ve organisms Broad secret agent attack InstaGram models that are both +ve and -ve

Question 32

What organisms are Narrow Spectrum agents used for?

Answer 32

Particular species of microorganisms Narrow secret agents attack specific influencers

Question 33

What are the 3 routes of Antimicrobial Administration?

Answer 33

1. Orally 2. Intramuscular 3. IV

Question 34

Even though Oral administration reaches the same therapeutic blood levels as rapidly as IV, when is IV preferred? (3 times)

Answer 34

1. Oral can't be tolerated (patient vomiting) 2. Oral can' be absorbed (malabsorbtion) 3. Patient critically ill

Question 35

What are the 3 side effects of Antimicrobial Agents?

Answer 35

1. Toxicity 2. Allergies 3. Changes to Normal Flora TAC

Question 36

What can Antimicrobial Agents be toxic to? (4 things)

Answer 36

1. Kidney 2. Liver 3. Nerves 4. Unborn foetus Secret agent poisons you

Question 37

What can allergies (from Antimicrobial Agents) cause?

Answer 37

Anaphylactic shock --> Death Secret agent shocks you and kills you

Question 38

What does changes to normal flora (caused by Antimicrobial Agents) cause?

Answer 38

Opportunistic pathogens to cause secondary infections Secret agent makes makes your opps morphe into secondary school opps dat kill u