Microbiology 20: Antimicrobials 1 Flashcards
What coverage do Glycopeptides antibiotics have ?
Gram +ve
When would Glycopeptide antibiotics be indicated ?
Gram +ve bacteria resistant to Beta lactams
E.g MRSA
Why are beta lactams considered bactericidal?
They dont kill existing bacteria, they inhibit cell wall synthesis so stop new bacteria from forming their cell walls and hence causing lysis.
Give 3 examples of classes of beta lactams ?
Penicillins
Cephalosporins
Carbapenems
Give an example of a drug that is a beta lactamase inhibitor?
Clavulanic acid
tazobactam
As you go up the generations of cephalosporins what happens to their activity against gram +ve and -ve bacteria ?
As you go up the generations the activity against gram -ve goes up and +ve goes down.
What complications can glycopeptides cause ?
Nephrotoxicity
Give 2 examples of Glycopeptides ?
Vancomycin
Teicoplanin
Which Glycopeptide is often used to treat C.difficile infection ?
Vancomycin
Which antibiotic is commonly used to treat meningitis ?
Ceftriaxone (cephalosporin)
Can’t normally penetrate blood brain barrier but does so when there is inflammation ie in meningitis
List 5 classes of Protein synthase inhibitors ?
Aminoglycosides Tetracyclines Macrolides Chloramphenicol Oxazolidinones (Linezolid)
Why are Proteinase inhibitors selective for bacteria and not hum an cells ?
They bind to the ribosomal subunit which is a different size in bacteria (30S) compared to human cells
What antibiotic coverage do Aminoglycosides (gentamicin) have ?
Good gram -ve activity
Poor gram +ve and anaerobe activity
what antibiotic coverage do Tetracyclines (doxycycline) have ?
Mostly gram +ve
Very good for intracellular pathogens e.g chlamydia and mycoplasma
Which class of Protein synthesis inhibitors are contraindicated in children and pregnant women ?
Tetracyclines
Deposit in bone and also cause discolouration of teeth
Chloramphenicol is contraindicated in the 3rd trimester as it can cause “grey baby syndrome”
What is a dangerous complication of giving babies chloramphenicol ?
Grey baby syndrome
Aplastic anaemia
What is the antibiotic coverage of Linezolid ?
Very active against gram +ve bacteria
Poor activity against gram -ve bacteria
In which infection is Linezolid particularly useful ?
MRSA
Give 2 side complications you can get with Linezolid ?
Optic neuritis
Thrombocytopenia
Give 2 classes of DNA synthesis inhibitors ?
Quinolones
Nitroimidazoles
What antibiotic coverage do quinolones (ciprofloxacin) have ?
very active against gram -ves
New quinolones: moxifloxicin and levofloxacin have more gram +ve cover than gram -ve
Give one example of a Nitroimidazole ?
Metronidazole
Which bacteria is Metronidazole particularly effective against ?
Anaerobes (C.Difficile)
Give one example of a class of RNA synthesis inhibitors ?
Rifampicins
