TX & Control of Bacterial and Fungal Infections Flashcards
What are antimicrobials?
Substance of natural, semisynthetic or synthetic origin that destroy microbes, prevent multiplication and growth or prevent pathogenic effect
Who discovered penicillin?
Alexander Fleming
What is an antibiotic?
Produced by microorganism that at low concentration inhibits or kills other microorganisms
T/F
All antibiotics are antimicrobials, but not all antimicrobials are antibiotics
True
What is the mode of action of antimicrobial agents?
Attack DNA, ribosomes, and cell wall
What are broad spectrum antimicrobials?
Active against both Gram + and Gram - organisms
Is knowledge of the intrinsic resistance of a pathogen important?
Yes
What is a bactericidal drug?
Antimicrobial that kills bacteria
What is a bacteriostatic drug?
Antimicrobial that inhibits bacteria
What knowledge is needed to use antimicrobial agent?
- Know the drugs
- Know the microbiology
- Know the patient
When do you use an antibiotic?
When the patient has a treatable microbial infection
What is non-therapeutic use of antibiotics?
- Growth promotion
2. Prophylactic or Metaphylactic use (prevent infection)
What is antimicrobial susceptibility testing (AST)?
Lab test to determine whether bacteria is susceptible to particular antimicrobial agent
Usually performed when selecting an antimicrobial for treatment
What two types of AST are there?
- Disk diffusion test (Kirby Bauer test)
2. Broth/Agar dilution test
What is minimum inhibitory concentration (MIC)?
Minimum amount of drug needed to inhibit bacterial growth
What is a susceptibility break point?
Drug concentration above which organism is considered resistant
The organism is susceptible to drug at or below this value
What are the 3 break point values?
- Susceptible: Likely successful
- Intermediate: uncertain
- Resistant: Likely failure
What must be used in a disk diffusion test?
Must use bacterial isolate in pure culture
Use published reference breakpoints
What is a broth dilution test?
Add multiple dilutions of antimicrobial agents in wells
Measure MIC
Use published reference breakpoints
Why do susceptibility testing?
Help Patients today, tomorrow, and in the next decade
What is pharmacokinetics?
Fate of drug in body
What is pharmacodynamics?
Effect of drug on the body
Why use antimicrobial combinations?
- Obtain antimicrobial synergism
- Treat polymicrobial infections
- Decrease emergence of antimicrobial resistance
- Reduce drug toxicity
What is innate resistance?
Pre-existing genomic property
What is acquired resistance?
Acquired by mutation or horizontal gene transfer
What are some problematic bacterial organisms?
- Organisms with innate resistance
- Vancomycin resistant Enterococcus (VRE)
- Methicillin resistant Staphylococcus aureus (MRSA)
- MDR & XDR Mycobacterium tuberculosis
What are some strategies to reduce antimicrobial resistance?
Prudent drug use
Pathogen control
Policy
