Microbiology 2 - Antimicrobial agents 1 Flashcards
What is the broad mechanism of action of beta lactams?
Inhibition of cell wall synthesis
What is the broad mechanism of action of glycopeptide antibiotics?
Inhibition of cell wall synthesis
What 3 groups of antibiotics are classified as beta lactams?
Penicillins
Cephalosporins
Carbapenems
Name 2 glycopeptide antibiotics
Vancomycin
Teicoplanin
Describe the mechanism of action of beta lactams
Inhibits transpeptidase, which is an enzyme that forms cross links during the formation of the cell wall.
The resulting cell wall is therefore weak, and so the bacteria lyse because of osmotic pressure.
How does the cell wall of gram pos and gram neg bacteria differ?
Gram pos has peptidoglycan
What bacteria is penicillin active against?
Gram pos
What bacteria is amoxicillin active against?
Broad spectrum: gram pos and many gram neg
Is streptococci gram pos or neg?
Gram pos
Which beta lactam antibiotic is effective against pseudomonas?
Piperacillin
How can beta lactam resistance be overcome?
Include a beta lactamase inhibitor
Eg. Clavulanic acid + amoxicllin (in co-amoxiclav)
Is pseudomonas gram pos or gram neg?
Gram neg (Pseudo"moan"as - 'moan' = negative)
Is neisseria meningitis gram pos or gram neg?
Gram neg (Neisseria starts with N = negative)
Recall an antibiotic that is associated with C. difficile
Ceftriaxone (cephalosporin)
Which beta lactam antibiotics are stable to ESBL organisms?
Carbapenems
Recall a caution of beta lactam antibiotic
Excreted renally so reduce dose if renal impairment
What type of bacteria are glycopeptides effective against?
Gram pos only - they are large molecules so can’t penetrate gram neg cell wall
What are glycopeptides particularly useful for?
MRSA infection
What is a caution of glycopeptide antibiotics?
They are nephrotoxic
Recall the broad mechanism of action of glycopeptide antibiotics
Prevent peptide cross links in cell wall
Recall the broad mechanism of action of aminoglycosides
Bind to 30s ribosomal subunit, preventing elongation of polypeptide chain
Recall 2 examples of aminoglycoside antibiotics
gentamicin
amikacin
What type of bacteria are aminoglycoside antibiotics effective against?
Gram neg
Recall 2 toxicities of aminoglycosides
Ototoxicity
Nephrotoxicity
What type of bacteria are macrolides effective against?
Gram pos