Antimicrobial therapy Flashcards
Antibiotics
Modes of action
-Inhibitors of cell wall synthesis
-Inhibitors of protein synthesis
-Inhibitors of nucleic acid synthesis
-Inhibitors of metabolic pathways
-Inhibitors of cytoplasmic membrane
function
-Inhibitors of fatty acid synthesis
Antiviral
Mode of action
Inhibit:
-Absorption to and
penetration of the cell
-Uncoating of the viral
nucleic acid
-Nucleic acid replication
-Assembly of new viral
particles
-Release of infectious virions
Antifungal
Mode of action
-Azole: inhibit the synthesis of ergosterol
-Polyenes: interact with fungal membrane sterols physicochemical
-5-fluorocytosine: inhibits macromolecular synthesis.
Assessment of antimicrobial susceptibility
-EUCAST disk diffusion test
-Broth Microdilution Method
-E-strip test
Antimicrobial resistance
mechanism
-Affinity of antibiotic for target reduced
-Alternative pathways
-Decreased uptake
-Enzymatic modification of the antimicrobial agent
Selective toxicity
To kill or inhibit the infecting organism without damaging the host cells (drug example - antibiotiocs)
Where do antibiotics come from?
-Other organisms (e.g fungi, soil bacteria)
-Synthetic
Why is selective toxicity hard to achieve in antivirals?
The survival of a virus depends on the hosts cell as it live inside them
Definition: Antimicrobial resistance
When a pathogen does not respond to medicines or they have mechanisms that make the medication ineffective
Definition: Antibiotic breakpoint
A maximum MIC ( Minimum inhibitory concentration) threshold for predicting successful antibiotic therapy
-Used to define if an organism is susceptible or resistant
Bacteriostatic antibiotic
Stops bacterial growth and reproduction without killing them
Total cell count and viable cells stay static
Bactericidal antibiotic
Kill the bacteria
Total cell count stays the same but viable cell count decreases
Bacteriolytic antibiotic
Destruction or dissolution of bacterial cells
Total cell count and viable count both decrease
