Lecture 7- Introduction to Antibiotics and Resistance Flashcards
Antimicrobial classification?
Antibacterial, antiprotazoal etc
Antibacterial further classified: Bactericides or bacteriostatic Broad or narrow spectrum Target site (mechanism of action) Chemical structure
How to choose an antibiotic?
Active against target? Reaches infection site? Formulation? Half life for dosing? Toxicity? Therapeutic drug monitoring? Allergies?
How to measure antibiotic activity?
Disc sensitivity testing
What is the minimum inhibitory concentration?
Lowest concentration of antibiotic required to inhibit growth of microorganism
Resistance types?
Intrinsic
Acquired
Adaptive
Beta lactams?
Broad spectrum such as amoxicillin and flucloxacillin but resistance developing fast
Penicillins?
Includes penicillin, flucloxacillin and amoxicillin
Cephalosporins?
Broad spectrum but no anaerobes activity
Cetriaxone has good csf activity
Carbapenems?
Very broad spectrum and active against most gram negatives
Glycopeptides?
Vancomycin Most active against gram positives
Narrow therapeutic window
Tetracycline and doxycycline?
Both used for gram pos when there’s a penicillin allergy
Don’t give to children under 12 or pregnant women
Active against chlamydia and some Protozoa
Aminoglycosides?
Gentamicin for gram neg treatment
Used in severe gram neg sepsis
Macrolides?
Erythromycin and clarithromycin
Alternative to penicillin for mild gram pos infections
Used also for atypical respiratory pathogens
Quinolone?
Ciprofloxacin
Active against gram negs
Increasing side effects being found
Trimethoprim and sulphonamides
Trimethoprim alone used for UTIs
Combined with sulphonamide becomes co-trimoxazole
