6: Antimicrobial Agents Flashcards
Why is antibiotics resistance bad?
Because antibiotics are used in routine medical practice in primary and secondary care
What is Antimicrobial Stewardship?
A systematic effort to educate + persuade antimicrobial prescribers to follow EVIDENCE-BASED prescribing
What are the benefits of Antimicrobial Stewardship? (3 things)
- Reduced Abx overuse
- Reduce Abx resistance
- Reduced Abx resistance developed @ an individual patient level AND community level
Where does MRSA cause infections? (4 places)
- Skin
- Soft tissue
- Bone
- Blood
Why is MRSA dangerous?
Develops resistance to new Abx quickly
How are MRSA infections transmitted?
Direct contact from person to person
What are the 2 types of MRSA infections?
- CA-MRSA (Community Acquired)
2. HA-MRSA (Hospital Acquired
What does CA-MRSA start as?
Skin infection
What does HA-MRSA start as?
Skin / wound / surgical site infection
What is the Pathogenesis of MRSA Infections?
- S. aureus synthesises Penicillin-binding Protein 2a (PBP2a)
- PBP2a has low affinity for Beta-lactams (produced by Abx)
- This low affinity allows for transpeptidase activity and cell wall synthesis
- This allows bacteria to grow and reproduce
What does S. aureus synthesise?
Penicillin-Binding Protein 2a (PBP2a)
What is special about PBP2a?
It has a low affinity for Beta-lactams
What are Beta-lactams produced by?
Abx
What does a low affinity for Beta-lactams allow?
Allows transpeptidase activity and cell wal synthesis –> allows bacteria to grow and reproduce
How are MRSA infections managed? (5 things)
- Healthcare professional + public education
- Fast detection in the lab
- Active surveillance
- Patient isolation
- Abx therapy
What are the 2 Abx used for MRSA infections?
- Glycopeptides (but expensive and toxic)
2. Flucloxacillin
What does Clostridium difficile cause? (2 things)
- Mucosal inflammation
2. Diarrhoea
What is the pathogenesis of Clostridium difficile colitis?
Alteration of normal bacteria flora of the colon caused by Abx
What is the management of Clostridium difficile?
Abx therapy but symptoms may reappear with prolonged Abx use –> so isolate the patient
What is the difference between Bactericidal vs Bacteriostatic drugs?
Bactericidal: KILL target organism
Bacteriostatic: INHIBIT / DELAY bacteria growth / reproduction
What is an example of a Bactericidal drug?
Penicillin
What is an example of a Bacteriostatic drug?
Tetracycline
Can some Abx be both Bactericidal and Bacteriostatic?
Yes
What are the 6 Mechanisms of Action of antimicrobial agents?
- Block pathogens Recognition / Attatchment to host
- Inhibit Cell Wall Synthesis
- Disrupt components of Cytoplasmic Membrane
- Inhibit General Metabolic Pathways
- Inhibit Protein Synthesis
- Inhibit Nucleic Acid Synthesis
(learn dem from outside of cell to inside nucleus ygm)
How does blocking pathogens Recognition / Attatchment to host work?
Stops virus from attaching to + entering the cell
How does inhibiting Cell Wall Synthesis work?
Prevents peptidoglycan synthesis by preventing CROSS-LINKING of NAM subunits (N-acetyglucosamine n dem man)
How does disrupting components of Cytoplasmic Membrane work?
Damages cell membrane –> causes leakage of important solutes needed for cell survival
How does inhibiting Protein Synthesis work?
This targets Mitochondria
Binds to subunits of ribosomes and disrupts protein metabolism
How does inhibiting Nucleic Acid Synthesis work?
Interrupts DNA replication / RNA translation
–> This inhibits bacterial multiplication + survival
What are the 2 spectrums of action of Antimicrobial Agents?
- Broad Spectrum
2. Narrow Spectrum
What organisms are Broad Spectrum agents used for?
Gram +ve and -ve organisms
Broad secret agent attack InstaGram models that are both +ve and -ve
What organisms are Narrow Spectrum agents used for?
Particular species of microorganisms
Narrow secret agents attack specific influencers
What are the 3 routes of Antimicrobial Administration?
- Orally
- Intramuscular
- IV
Even though Oral administration reaches the same therapeutic blood levels as rapidly as IV, when is IV preferred? (3 times)
- Oral can’t be tolerated (patient vomiting)
- Oral can’ be absorbed (malabsorbtion)
- Patient critically ill
What are the 3 side effects of Antimicrobial Agents?
- Toxicity
- Allergies
- Changes to Normal Flora
TAC
What can Antimicrobial Agents be toxic to? (4 things)
- Kidney
- Liver
- Nerves
- Unborn foetus
Secret agent poisons you
What can allergies (from Antimicrobial Agents) cause?
Anaphylactic shock –> Death
Secret agent shocks you and kills you
What does changes to normal flora (caused by Antimicrobial Agents) cause?
Opportunistic pathogens to cause secondary infections
Secret agent makes makes your opps morphe into secondary school opps dat kill u
