(FE) General Principles of Antimicrobials Flashcards
What is the difference between:
- Pathogen
- Pathogenicity
- Virulence
- Invasiveness
Pathogen:
- Microbes that are capable of causing disease
Pathogenicity:
- Ability of an organism to cause infection
Virulence:
- Severity of disease caused by pathogen / harmfulness of pathogen
- Highly virulent microbe can produce disease even in minute numbers
Invasiveness:
- Ability of pathogen to grow rapidly and cause direct damage to surrounding tissue by the numbers
What are the common pathogens?
- Parasites
- Protozoa
- Fungi
- Prokaryote
- Virus
- Prion
What are the 2 mechanisms that pathogens use to cause disease?
- Invasiveness
- Toxin production
How are bacteria classified?
- By the way they stain (ie Gram pos/neg)
- By shape (ie rods, spirals, spheres)
- By ability to use oxygen
What are some examples of anaerobic infections?
- Intraabdominal infections (from perforated viscus)
- DM foot infection
What are the ideal microbes?
Toxic only to microbes but not to the human cells
Classifications of antimicrobial agents?
1) Protein synthesis inhibitors acting on ribosomes
2) Folic acid synthesis in the cytoplasm
- Inhibit metabolism
3) Cell wall inhibitors
- Blocks synthesis and repair
4) Cell membrane
- Causes loss of selective permeability
5) DNA/RNA
- Inhibits replication and transcription
- Inhibits gyrase (unwinding enzyme)
How does antibiotic resistance occur in microbes?
1) Antimicrobials kill the bacteria causing illness, and good bacteria in the body
2) Only the drug-resistant bacteria are killed and now take over the body
3) Some bacteria give their drug-resistance to other bacteria, and cause more problems
How does antibiotic resistance spread in the community?
1) Person w/ antibiotic resistance -> spread to others in community/patients/HCP/surfaces
2) Animals w/antibiotic resistance -> fertiliser on crops/bacteria remain on meat which are consumed when meat is not handled or cooked well -> spread to humans
What are the mechanisms of acquired resistance?
1) Change in antimicrobial target (usual site of attack doesnt exist)
2) Nullifying cell permeability to drug penetration (drug cannot enter cell)
3) Decreased uptake of antibiotic by expression of efflux pump (drug gets kicked out of cell)
4) Production of enzyme that inactivates drug (drug may as well doesnt exist)
5) Production of an alternate pathway that bypasses the action of drug (drug doesnt work on cell)
6) Biofilm formation (extra protection from environment)
What are nosocomial infections?
- Healthcare-acquired infections
- High sick human traffic
- MRSA and VRE common
What is the systemic approach to antimicrobial use? (IMPT)
1) Confirm the presence of infection
- Risk factors
- Subjective/objective evidence
- Site of infection
2) Identify pathogens
- Microbiological tests and results
3) Select antimicrobial agent and regimen
- Empirical/definitive/prophylaxis
- Agent, route, dosage and duration
4) Monitor response to drug
- Therapeutic response
- Adverse reactions
What is the difference between pharmacokinetics and pharmacodynamics?
Pharmacokinetics:
- Movement of drug through body
- How body affects drugs
- Absorption, distribution, metabolism & excretion
Pharmacodynamics:
- How drug affects the body
- Toxicity, efficacy & potency of drug
What is the decision triad for choosing an antimicrobial agent?
Patient vs Antimicrobial Agent vs Organism
- Clinical status, allergies, risk factors, demographic, organ function
- PK, PD, drug interactions, side effects, cost
- Anticipated drug sensitivity, drug resistance, pathogenicity/virulence, ease of detection
What are the nursing implications to delay emergence of antimicrobial resistance?
- Prevent infections through vaccination
- Use the right drug for infection
- Restrict use of antibiotics to only when necessary
- Watch out for adverse effects
- Educate patients to use full course of antibiotics
- Prevent transmission of pathogen
