Antibiotics Flashcards
How do beta lactam drugs disrupt cell wall synthesis?
Bind to penicillin-binding proteins (PBP) inhibiting transpeptidases responsible for cross linking proteoglycans.
Think penicillinoic acid think…
… degratation product - HYPERSENSITIVITY.
Which type are outer (and inner) membrane surfactants?
Polymixins (polymixin B and E)
Which polymixin in only used topically?
For example could be on an infected bee sting…
Polymixin B.
Two side effects of polymixins:
neurotoxicity and nephrotoxicity
How do quinolones stop DNA synthesis?
topoisomerase inhibitors.
What do rifamycins inhibit that afford it selectivity?
Inhibit bacterial DNA dependent RNA polymerase (not human RNA polymerase)
Two side effects of rifampin/rifampicin
Remember that liver transplant video.
Hepatotoxicity, discolouration of body fluids
What drug would leprosy and tuberculosis need?
Rifampicin (rifamycins)
What are rifamycins good for?
leprosy and tuberculosis.
T of F - resistance develops quickly in rifamycins?
TRUE (RIfamycins - REsistance)
Which drugs bind to the 30s subunit?
aminoglycosides,
tetracycline/doxycycline
Which of the protein inhibiting drugs is the one that binds to the 50s subunit (not the 30S)?
Chloramphenicol
What helps tetracycline selectivity along?
Not 100% selective
Accumulation via transport protein in the bacterial membrane.
What can’t you eat with tetracycline?
Milk, aluminium, iron.
What bacteria are aminoglycosides ineffective against?
+ve as well as strict anaerobes.
_____ are good for most hospital acquired ANAEROBIC -VE bacteria.
Aminoglycosides
Why aren’t amiNOglycosides effective against anaeobes?
Transport into the bacterium requires
What’s PABA?
That’s the precursor to folate that bacteria need to convert. (p-aminobenzanoic acid)
Which folate enzyme does tRimethopRim inhibit?
dihydrofolate Reductase
Which folate enzyme do SulphanamideS inhibit?
dihydropteroate Synthase
T or F: you’d expect sulphanamides to be given in combination with trimethoprim.
YES.
Quinolones are ______ and all end in ______.
Topoisomerase (DNA) inhibitors; -flaxacin.
What are two beta-lactamase inhibitors that you can combine with beta lactam drugs?
Clavulanic acid
Sulbactam
What is clavulanic acid?
Beta-lactamase inhibitor
What is sulbactam
Beta-actamase inhibitor
Where would beta-lactamase inhibitors not be effective?
Another kind of resistance is make PBPs with low affinity for beta-lactam antibiotics.