Antimicrobial Flashcards
Microorganisms causing infection
Pathogens
causing cell death without affecting the host cell
Selective Toxicity
Optimal antimicrobial therapy is described by four (4) D’s:
right Drug
right Dose
right Duration of therapy
Decreased collateral damage
This is known when pathogenic microorganism is usually identified prior to the start of antibiotic therapy.
Definitive antimicrobial therapy
The microbial identification is done through several mechanism:
culture and sensitivity test
history taking
physical assessment
selection of antimicrobials may be based on the following:
sensitivity of the pathogen
site of infection
status of organ function
special population group
likelihood of resistance
classification of antimicrobial agents according to their overall effect on the microorganism:
bacteriostatic
bactericidal
these antimicrobials slow or retard bacterial cell’s ability to
reproduce or divide
bacteriostatic
these are antibiotics that cause cellular death
bactericidal
classification of antimicrobial agents according to their scope of effectiveness:
narrow spectrum
broad spectrum
these antimicrobials are effective against a limited type of
microorganisms; used in definitive therapy (e.g. isoniazid)
narrow spectrum
these antimicrobials are effective against a wide variety of
microorganisms from the same strain; usually indicated for empiric therapy (e.g. tetracyclines)
broad spectrum
classification of antimicrobial agents according to purpose:
curative
prophylactic
these are antibiotics that are used to treat an existing infection
curative
these antibiotics are used to prevent possible infection from
occurring
prophylactic
General Mechanism of Action of Antimicrobial Agents:
- interfere with the biosynthesis of the cell wall
- alter the permeability of the cell membrane
- inhibit synthesis and replication of RNA and DNA
- interfere with the steps in CHON synthesis
- alter other metabolic processes within the cell
this action of antibiotics results in the cell’s loss of structural integrity, which eventually leads to cell death
interfere with the biosynthesis of the cell wall
this action results in the leakage of cellular components, which leads to cellular degeneration and death
alter the permeability of the cell membrane
when the process of RNA and DNA synthesis is altered, cells cannot grow and multiply, which results to diminished number of cells and eventual cellular death
inhibit synthesis and replication of RNA and DNA
when protein synthesis is altered, cell division may be altered; hence, the cell will not be able to grow and divide, which results to diminished number of cells
interfere with the steps in CHON synthesis
alteration in the various processes that are crucial for normal cellular functioning can lead to cellular starvation
alter other metabolic processes within the cell
which antibiotic group is the most common cause of drug allergy?
penicillin group
Nephrotoxicity is an adverse effect that is most frequent with drugs such as:
aminoglycosides
amphotericin B
quinolones
vancomycin
Signs and Symptoms of Nephrotoxicity:
elevated blood urea nitrogen (BUN) and creatinine
presence of edema
muscle cramps
weakness
fatigue
development of hypertension and anemia
