4.2 Antibitoic resistance Flashcards
Outline the classification of antimicrobials
Bactericides VS Bacteriostatic
Spectrum (B-road VS Narrow)
Target site (mechanism of action)
Chemical structure (antibacterial class)
Factors when choosing antibiotics
Cause of infection
Active against target organism
Site of infection
Right formulation (e.g. IV, oral)
Half life (dosing frequency)
Interaction with other drugs
Therapeutic drug monitoring
Methods of measuring antibiotic activity
Disc diffusion testing
-zone size determines antibiotic resistance
Broth microdilution
-MIN: minimum inhibitory conc.
What is MIC (minimum inhibitory conc.)
Minimum con. of antimicrobial agent at which visible growth is inhibited
Classes of antibacterials
Cell wall synthesis
Cell membrane function
Protein synthesis
Nuclei acid synthesis
Types of resistance
Intrinsic
Acquired
Adaptive
Mechanisms of resistance
-Enzymatic modification/destruction of antibiotics
-Enzymatic alteration of antibiotic targets
-Mutations of bacterial targets sites
Antibacterials that act against cell wall synthesis
-Beta-lactams
(Penicillins, cephalosporins, carbapenems)
-Glycopeptides
Antibacterials that acts against cell membrane function
Polymixins (e.g. colistin)
Antibacterials that act against protein synthesis
Tetracyclines (30s)
Aminoglycosides (30s)
Macrolides (50s)
Antibacterials that acts against nuclei acid synthesis
Quinolones (DNA gyrase)
Trimethoprim (folate synthesis)
Rifampicin (RNA polymerase)
Examples of Beta-lactate
Penicillins
Cephalosporins
Carbapenems
Glycopeptides
Different types of penicillins
Penicillin: streptococci
Amoxicillin: Gram-negatives
Flucloxacillin: staphylococci & streptococci
Co-amoxiclav: all of above, anaerobes
Piperacillin/tazobactam: as above,
Classification of Beta-lactatams
Penicillin
Cephalosporins
Carbapenems
Monobactams
