Micro + abx Flashcards
What colour do gram +ve bacteria stain?
Purple
What colour do gram -ve bacteria stain?
Pink
Give some examples of gram -ve bacteria
- E.coli
- Salmonella
- Shigella
- Pseudomonas
Remember as commonly associated with the gut
Which gram +ve cocci form clusters?
Staphylococcus
Which gram +ve cocci form chains?
Streptococcus
What are the 3 mechanisms of antibiotic action?
1) Inhibit cell wall synthesis
2) Inhibit protein synthesis
3) Inhibit nucleic acid synthesis
Which abx classes inhibit cell wall synthesis?
- Beta lactams
- Glycopeptides
What are beta lactam abx?
- Penicillins
- Cephalosporins
- Carbapenems
Which abx classes inhibit protein synthesis?
- Macrolides
- Tetracyclines
- Aminoglycosides
Which abx classes inhibit nucleic acid synthesis?
- Quinolones
- Sulfonamides
Give examples of penicillins
- Amoxicillin
- Pen V
- Flucloxacillin
- Co-amoxiclav contains clavulanic acid/amoxicillin
Give examples of cephalosporins
- Cephalexin
- Ceftriaxone
- Cefuroxime
Give examples of carbapenems
- Meropenem
Give examples of glycopeptides
- Vancomycin
- Teicoplanin
- Telavancin
Give examples of macrolides
- Azithromycin
- Clarithromycin
- Erythromycin
Give examples of tetracyclines
- Doxycycline
- Lymecycline
Give examples of aminoglycosides
- Gentamicin
- Neomycin
- Streptomycin
Give examples of quinolones
- Ciprofloxacin
- Levofloxacine
Give examples of sulfonamides
- Sulfasalazine
What do bactericidal vs bacteriostatic abx do? When are they useful?
Bactericidal:
- Kill the bacteria
- Generally by inhibiting cell wall synthesis
- Useful for difficult to treat infections or those that need quick eradication e.g. meningitis
Bacteriostatic:
- Prevent bacteria multiplying
- Inhibit protein synthesis/DNA replication
- Useful for reducing toxin production e.g. in severe cellulitis/nec. fasciitis, toxic shock syndrome
What is pharmacokinetics?
The movement of a drug from its administration site to the place of its pharmacologic activity and then its elimination from the body
Which abx can cause C. Diff?
- Cephalosporins
- Carbapenems
- Co-amoxiclav
- Ciprofloxacin
- Clindamycin
What are important resistant gram positive bacteria? What are they resistant to?
- MRSA
- Methicillin resistant Staph aureus
- Resistant to all beta lactic abx as well as methicillin (?fluclox) - VRE
- Vancomycin-resistant enterococci
- Resistant to vancomycin
- Promoted by cephalosporin use
What are important resistant gram negative bacteria? What are they sensitive to?
- ESBL
- Extended spectrum beta lactamase
- Sensitive to beta-lactamase inhibitors -> clavulanate added to amoxicillin = co-amoxiclav, tazobactam added to pipericillin = tazocin - CRE
- Carbapenem resistant enterobacteriaceae
- Tx options are very few and very toxic
What stepwise approach for remembering what abx cover which bacteria?
- Amoxicillin - covers strep, listeria, enterococci
- Switch to co-amox - covers staph, haemophilus, E.coli
- Switch to tazocin - covers pseudomonas
- Switch to meopenem - covers ESBLs
- Add vancomycin/teicoplanin - covers MRSA
- Add Clarithromycin/doxycycline - covers atypical bacteria
Each consecutive step covers the bacteria in the previous
