Week 2 Flashcards
(42 cards)
What are the different ways to target bacteria?
Inhibition of cell wall synthesis
Inhibition of protein synthesis
Interference with metabolic pathways
Inhibition of nucleic acid synthesis
Disruption of the cell membrane
What drug classes are the beta-lactams?
Penicillins, cephalosproins, monobactams and carbapenams
How do beta-lactams work?
Inhibtion of penicillin-binding protein transpeptidase (PBP)
What is the function of PBP?
polymerize and modify peptidoglycan, the stress-bearing component of the bacterial cell wall.
What do beta-lactamases do?
They are the primary reason for resistance on beta-lactams. Beta-lactamases that target penicillin antibiotics and render them inactive are commonly referred to as penicillinases, while those that can hydrolyse cephalosporin antibiotics are known as cephalosporinases.
What are the beta-lactamase inhibitors called?
Clavulanic acid, tazobactam and avibactam.
What are the anti-staphylococcal penicillins? (except MRSA)
Dicloxacillin and flucloxacillin.
What are the aminopenicillins?
Amoxicillin and ampicillin.
What is the antipseudomonal penicillin?
Piperacillin (has action against pseudomonas aeruginosa.
What is the main difference between penicilins and cephalosporins?
Cephalosporins have a broader spectrum of activity.
What are features of 1st generation cephalosporins?
Cefalexin and cefazolin, moderate-spectrum, activity against s. aureus, used for streptococcal, do not cross BBB, increases risk of bleeding and effective against gram-positive.
What are the features of 2nd generation cephalosporins?
Cefaclor, cefoxitin and cefuroxime, moderate spectrum, improved gram-negative and weakened gram-positive coverage. Mainly used for bacterial upper respiratory tract infections. Do not cross BBB.
What are the features of 3rd generation cephalosporins?
cefotaxime, ceftazidine, ceftriaxone. Broad-specturm, more gram-negative coverage, can cross the BBB, strongly associated with clostridioides difficle-associated diarrhoea. Ceftazidime has anti-pseudomonal activity.
What are the features of 4th generation cephalosporins?
Cefepime. Broadest spectrum, similar Gram-positive coverage to the first-generation cephalosporins, covers many Gram-negative bacteria including, covers S. aureus. Reserved for treatment of multiresistant organisms, or for treating sepsis in neutropenic or immunosuppressed persons.
What are the features of 5th generation cephalosporins?
Only available for parenteral administration (ceftaroline fosamil, ceftolozane-tazobactam). Ceftaroline is the only cephalosporin for MRSA but does not cover pseudomonas aeruginosa. Ceftolozane-tazobactam has reduced Gram-positive coverage. In particular, it does not cover Staphylococci. It however does cover Pseudomonas aeruginosa.
What is the monobactam?
Aztreonam.
What are the features of aztreonam?
Safe for patients with allergies to other beta-lactams, except ceftazidime, Aztreonam has anti-pseudomonal activity. It is sensitive to inactivation by extended-spectrum beta-lactamases (ESBLs).
What are the features of carbepanems?
only available for parenteral administration (imipenem-cilastatin, ertapenem, meropenem). Most broad-spectrum antibiotics available, active towards S. aureus but are not effective for MRSA or VRE. Ertapenem is given once daily and has poor activity against important hospital acquired infections (e.g. Pseudomonas aeruginosa, Enterobacter faecalis, Acinetobacter species). Imipenem is administered with cilastatin, which prevents its inactivation in the kidney.
What are the glycopeptides?
Vancomycin and teicoplanin
What are the features of glycopeptides?
preventing cross-linking of peptidoglycan. Non-covalently bind with high affinity to the D-Alanine-D-Alanine terminus, mainly active against Gram-positive bacteria, useful for treating Staphylococci, including MRSA, Streptococci and Clostridioides difficile. When infused too fast, can cause histamine release, which causes the patient to become warm, flushed and hypotensive (red man sydrome).
Which drugs are aminoglycosides?
Amikacin, gentamicin, streptomycin and tobramycin.
What is the MOA for aminoglycosides?
bind to the bacterial 30S ribosomal subunit. Results in the production of incorrect proteins, which can damage the cell membrane, enhancing aminoglycoside entry, and affecting other processes, resulting in bactericidal activity.
Can aminoglycosides be administered with beta-lactams?
No as they are incompatible when mixed.
What are the macrolides?
Erythromycin, clarithromycin, azithromycin and roxithromycin.
