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Flashcards in Antimicrobials Deck (15):
1

Antibiotic

traditionally referred to substances produced by microorganisms to suppress the growth of other microorganisms

2

Antimicrobials

broader, refers to antibiotics synthesized in the laboratory as well as those synthesized by other microorganisms

3

Which antimicrobial actually kills the organism?

Bacteriocidal
- 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)

4

Which antimicrobial inhibits growth of bacteria but DOES NOT KILL?

Bacteriostatic
- 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.

5

have activity against a wide range of drugs (Fluoroquinolones)

Broad Spectrum

6

have activity against a single species or a limited group of pathogens (Penicillin)

Narrow Spectrum drug

7

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.
-

8

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

9

Microbial resistance can be innate(they secrete that already destroys it) or acquired(contact with drugs giving).

TRUE

10

When does resistance develop?

- Misuse of drug (short duration
- dose is too low
- infection recurs

11

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

12

What is appropriate selection of antimicrobial drugs based on?

- type of infection
- status of pt
- drug properties

13

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

14

Status of pt depends on

Prego
Allergies
Age
Renal impairment
Hepatic Insufficiency
Abscesses
Presence of indwelling catheters

15

Drug properties depend on

PK
- Drug concentrations low in bone, pts with osteomyelitis must be treated for several weeks(get higher concentration)
- Route of elimination – renally excreted drugs good for UTI, however may accumulate in pts with renal impairment and cause increased toxicity (AMG VERY TOXIC).
- Adverse effect profile – risk to benefit ratio
- Cost - consider total cost (drug + administration + monitoring.)
- Convenience – consider frequency and duration( once or twice a day same shit like amoxicillin)