Antimicrobial Drugs - Penicillins Flashcards
What is the difference between bacteriostatic and bacteriocidal drugs?
Bacteriostatic: a drug which arrests the growth and replication of a bacterioum.
Bactericidal: a drug which kills bacteria.
What makes an organism Gram-positive?
thick peptidoglycan layer in the cell wall that can be stained purple by a primary basic dye.
What makes an organism Gram-negative?
thin peptidoglycan layer in the cell wall that doesn’t stain purple.
What is Inherent Resistance?
Gram-negative bacteria are inherently resistant to vancomycin
What bacteria have Inherent Resistance?
Gram-negative bacteria are inherently resistant to vancomycin
How do genetic alterations lead to drug resistance?
Spontaneous mutations of DNA -
or -
DNA transfer of drug resistance from one bacterium to another via PLASMIDS
How do protein alterations lead to drug resistance?
alteration of an antibiotics target sites through mutation -
decreased uptake of increased efflux of antibiotic causing decreased accumulation and insufficient concentration -
enzymatic inactivation of antibacterial agents
What is the MOA of Inhibitors of Cell Wall Synthesis?
Inhibit the formation of cross-linking of adjacent peptidoglycan strands in the bacterial cell wall. They are structurally similar to the terminal portion of the peptidoglycan strands and can compete for and bind to the enzymes that catalyze the cross linking.
What are Inhibitors of Cell Wall Synthesis?
Penicillin, Cephalosporin
Which penicillin is natural? What is it used for?
Benzathine Penicillin G - best for syphilis
Which penicillin are Penicillinase Resistant? What are they used for?
Nafcillin, Oxacillin - reserved for penicillinase-producing Staph. aureus
What is the penicillin type used for Listeria Monocytogens?
Extended-spectrum penicillins (like ampicillin)
What penicillin is a combination?
Augmentin: Amoxicillin + clavulanic acid
What penicillin are Antipseudomonal?
Peperacillin(most potent), Carbenicillin -
effective against pseudomonas aeruginosa
What is the adverse effect of penicillins as a group?
Hypersensitivity reaction which may be fatal.
