MCQ's: Antibiotics Flashcards
Which of these antibiotics are effective against anaerobic bacteria?
Imipenem, metronidazole, trimethoprim, aztreonam, vancomycin
Metronidazole - anaerobes and parasites
Imipenem - broad spectrum including some anaerobes
Aztreonam covers which bacteria?
Aztreonam is a monobactam and covers a wide range of gram negative
What are bacteriocidal antibiotics?
Penicillins Cephalosporins Carbapenems Aminoglycosides Quinolone Metronidazole Vancomycin
Which antibiotics are bacteriastatic?
Sulphonamide
Tetracyclines
What is the mechanism of benzylpenicillin?
Inhibits cell wall synthesis
Mechanism of actions of cephalosporins?
Inhibit cell wall synthesis.
All beta-lactams rings binds to proteins and prevent peptidoglycan cross-linkage in the bacterial cell-wall thus weakening it.
Gentamicin mechanism of action?
Arrests protein synthesis by binding to 30S ribosomal RNA subunit.
How does ciprofloxacin work?
Inhibits DNA synthase
Mechanism of action of Rifampicin?
Binds to the RNA subunit of DNA-dependant RNA polymerase, preventing bacterial protein synthesis
Agents that cover MRSA?
Meropenem, Ciprofloxacin, Vancomycin, Clindamycin, Fusidic acid, Teicoplanin
Which of these have gram negative cover?
Vanc, gentamicin, ciprofloxacin, aztreonam, metronidazole
Gentamicin, Ciprofloxacin, Aztreonam
Mechanism of action of Amphotericin B?
Creates pores in the fungal cell membrane
Which azole antifungals are well absorbed orally?
All azoles except Miconazole
How do azole antifungals work?
By affecting fungal ergosterol synthesis
True or false:
dose adjustment is needed for ketoconazole in patients with renal failure.
False.
Ketoconazole is metabolised in the liver and inactive metabolites are excreted in the bile. No dose adjustment needed in renal failure.
Which antibiotic cause ototoxicity?
Vancomycin and Gentamicin
Which antibiotic causes red discolouration of body fluids?
Rifampicin
Which antibiotics can increase the potency and duration of non-depolarising muscle relaxants?
Aminoglycosides- decrease pre-junctional release of ACh and reducing sensitivity post junctional ACh
ie. amikacin, gentamicin, neomycin sulfate, streptomycin, and tobramycin.
Which antibiotics can cause discolouration in children’s teeth?
Tetracyclines
Which antibiotic can cause Red Man Syndrome and what is it?
Vancomycin- causes histamine release and associated symptoms include widespread rash known as red man syndrome.
Which Abx are sensitive to B-lactamase enzymes produced by resistant bacteria?
Which are resistant?
Piperacillin and Benzylpenicillin are sensitive.
Meropenem (very) and Flucloxacillin (moderately) are resistant.
Can Amphotericin B be orally administered?
No, only IV
What antibiotics can be both bacteriocidal or bacteriostatic?
Macrolides such as a Azithromycin/ clarithromycin/ erythromycin etc depending on their plasma concentration.
