Antibiotics for interns Flashcards
Narrow spectrum penicillins
Penicillin
Fluclox
Moderate spectrum penicillins
Amoxi
Amp
Broad spectrum penicillins
Ticarcillin
Piperacillin
1st gen cephalosporins
Cephazolin
Cephalexin
2nd gen cephalosporins
Cefaclor
3rd gen cephalosporins
Ceftriaxone
Cefotaxime
4th gen cephalosporins
Ceftazidime
Cefepime
5th gen cephalosporins
Ceftaroline
Carbapenems
Meropenem
Imipenem
Ertapenem
Mechanism of action of B-lactams
Bind to PBPs in bacterial cell walls to inhibit peptidoglycan (and therefore cell wall) synthesis)
B-lactams: bacteriostatic or bactericidal?
Bactericidal (except for Enterococcus)
Is bacterial killing by B-lactams concentration-dependent or -independent? Relevance to management?
Concentration-independent (TIME above MIC is what dictates efficacy)
Give frequent low doses
Absorption of B-lactams
Variable oral absorption (gastric acid degrades many penicillins, food delays rate and extent of absorption)
3 mechanisms of resistance to B-lactams (including examples of bacteria which utilise these)
Production of B-lactamase (MSSA, E. coli)
Alteration in PBPs to decrease binding affinity (MRSA, Strep pneumo)
Alteration of outer membrane to decrease penetration
Benzylpenicillin (pen B), amoxi, amp spectrum of activity
Strep/enterococci
E.coli/Klebs/Haem (amp)
Anaerobes (gram+ oral)
B-lactams
Pencillins
Cephalosporins
Carbapenems
Typical administration of amp vs amoxi
Amp: IV
Amoxi: oral
MSCNS
Methicillin-susc coag-negative Staph
Amoxiclav spectrum of activity
MSSA, MSCNS
Strep/enterococci
E.coli/Klebs/Haem
Some bowel anaerobes
Fluclox/diclox
MSSA, MSCNS
Some activity against Strep pyogenes
Ticarc/clav, piper/tazobactam spectrum of activity
MSSA, MSCNS Strep/enterococci E.coli/Klebs/Haem Pseudomonas Anaerobes
Cephalosporins CANNOT be used for?
Enterococci
1st gen ceph spectrum of activity
MSSA, MSCNS
Strep
E.coli/Klebs/Haem (generally not)
3rd gen ceph spectrum of activity
MSSA, MSCNS
Strep
E. coli/Klebs/Haem
Some anaerobes