Flashcards in Antimicrobials Deck (15):
traditionally referred to substances produced by microorganisms to suppress the growth of other microorganisms
broader, refers to antibiotics synthesized in the laboratory as well as those synthesized by other microorganisms
Which antimicrobial actually kills the organism?
- Organism falls rapidly after drug exposure
- Induce LETHAL changes in microbial metabolism or block activities essential for viability
- ***like likely to cause resistance*** actively destroying
- Includes most antimicrobial drugs (B lactams, Quinolones, aminoglycosides, advanced macrolides)
Which antimicrobial inhibits growth of bacteria but DOES NOT KILL?
- Number of organisms remains relatively constant after drug exposure
- Require immunologic mechanisms to eliminate organism
- Inhibit a metabolic rxn needed for cell growth but not necessary for viability
- More likely to cause resistance
- Examples of bacteriostatic drugs include sulfonamides, tetracyclines and erythromycin macrolides.
have activity against a wide range of drugs (Fluoroquinolones)
have activity against a single species or a limited group of pathogens (Penicillin)
Narrow Spectrum drug
What determines the exact organism responsible for an infection and thee antibiotics that it is sensitive or resistant too?
Culture and sensitivity, takes 72 hours and start with empiric treatment.
What are organisms classified as having HIGH susceptibility, intermediate sensitivity or resistance?
Based on Minimum Inhibitory Concentration (MIC) to the drug tested.
- MIC is the LOWEST concentration of the drug that inhibits bacterial growth
Microbial resistance can be innate(they secrete that already destroys it) or acquired(contact with drugs giving).
When does resistance develop?
- Misuse of drug (short duration
- dose is too low
- infection recurs
What are the 3 mechanisms that cause resistance to a drug?
- Inactivation by microbial enzymes ( beta Lactamase)
- Decreased accumulation of drug by microbe( block entrance)
- Reduced affinity of the target molecule by the drug
What is appropriate selection of antimicrobial drugs based on?
- type of infection
- status of pt
- drug properties
Type of infection is based on
- lab results
- knowledge of most common organisms causing various types of infections and drugs (EMPIRIC THERAPY)
- Empiric therapy FIRST, until lab results come back of minor URI/UTI cuz you know the causative organism and sensitivity
Status of pt depends on
Presence of indwelling catheters