Antibacterial: General Drug and Resistance Mechanisms Flashcards
Do G+ Bacteria have a thick or thin peptidoglycan layer?
Thick
Do G- Bacteria have a thick or thin peptidoglycan layer?
Thin
What is the Makeup of LPS?
Phospholipid and Polysaccharide
What is the Bacterial Cell wall composed of?
Peptidoglycan
What is the difference between prokariotic and eukariotic cell membrane?
Sterols in Eukariotic CM
What is the Purpose of LPS in G- bacteria?
Prevents penetration of bulky, high molecular wt antibiotics, erythromycin.
What is the Purpose of Lipid bilayer in G- bacteria?
Greatly reduces penetration of Water soluable drugs
What is the Purpose of the hydrophilic pores in G- bacteria?
Allows penetration of Water sol. molecules up to 650 daltons (sulfonamides)
What is the Purpose of the nutrient receptor pores on the outer membrane in G- bacteria?
Agents sturcturally related to nutrients use these receptors.
What is the Purpose of the Teichoic Acid in G+ bacteria?
Strong anionic character affects rate of penetration
What is the Purpose of the Lipid bilayer of the cytoplasmic memrane in G+ bacteria?
Rate of penetration depends on lipophilicity
What is the Purpose of the nutrient transport protiens on the cytoplasmic membrane in G+ bacteria?
Facilitated rapid penetration of agents similar in structure
Cyclosporine, phosphomycin, tetracycline
What is the MBC?
Minimum Bacteriocidal/Bacteriostatic Concentration
What is Pre-Emptive Therapy?
Treatment of succeptible patients that don’t yet have symptoms.
What is the difference between Empirical and Definitive therapy?
Empirical: Don’t know organism
Definitive: Know the organism
What are the Nosocomial Superbugs?
ESKAPE
Enterococcus faecium Staphylococcus aureus Klebsiella pneumoniae Acinetobacter baumanii Pseudomonas aeruginosa Enterobacter sp.
What is the style of resistance daptomycin?
Reduced drug entry into the organism
How does the bacteria reduce entry of Abtx?
Overall increase in the net positive membrane charge
What is the style of resistance tetracycline?
Increased drug export
What is the style of resistance Metronidazoe?
Change in activation of Pro-Drug.
How is Metronidazole activated y bacterial clls?
Reduced
What is the style of resistance of Aminoglycosides (streptomycin)?
Expression of ezymes that destroy the drug
What is the style of resistance of amoxicillin?
B-Lactamase breaks the B-Lactam ring.
How is B-Lactamase blocked?
Clavulonic Acid (Augmentin)
What is the style of resistance Trimethoprim and Sulfonamides?
Impaired drug binding to the original target
What is the style of resistance vancomycin?
New or different pathways that aren’t inhibited by the drug. (Cell wall synthesis)
