Infection: Antimicrobials Flashcards
How are antibacterials classified?
Bactericidal (kill bacteria) or bacteriostatic (inhibit growth)
Broad or narrow spectrum
Target site
Chemical structure
What are the 4 different mechanisms of action of antibacterials? Give an example for each
Most important
Inhibit cell wall synthesis - beta lactams and glycopeptides (penicillin and vancomycin)
Inhibit protein synthesis - tetracyclines
Inhibit nucleic acid synthesis - quinolones, rifampicin
Inhibit cell membrane function
Least important
What bacteria is vancomycin effective against?
gram +ves
has a narrow therapeutic window so needs close monitoring
What are the mechanisms of resistance of antimicrobials?
- Drug inactivating enzymes that destroy the antibiotic before it can work eg beta lactamases destroy beta lactams
- Altered target eg the target enzyme has a lower affinity for the antibacterial
- Altered uptake, either decreased permeability or increased efflux
What bacteria are penicillins effective against?
Mainly active against streptococci and gram negatives
Name some penicillins are what they are effective against
Penicillin - steptococci
Amoxicillin - gram +ves with some activity against g -ves
Flucloxicillin - streptococci and staphylococci
Co-amoxiclav - mixture of amoxicillin and some g-ve
What bacteria is cetriaxone effective against?
Broad spectrum
Has good activity in cerebral spinal fluid so good for use in meningitis
What condition is meropenem used for?
Used for life threatening sepsis with an unknown cause - very broad spectrum
What bacteria is doxycycline effective against?
Broad spectrum but commonly used for g+ve in penicillin allergy
Used for atypical pneumonia
What bacteria is gentamycin effective against?
Profound activity against g-ves (so reserved for severe gram negative sepsis)
can be potentially nephrotoxic
What is erythromycin used for?
Alternative to penicillin in mild g+ve infection
Active against atypical respiratory pathogens
What is ciprofloxacin effective against?
Very active against g-ves and atypical pathogens
High risk of C difficile
What is trimehtoprim used to treat?
UTIs
What is antimicrobial stewardship?
A program that promotes the appropriate use of antimicrobials, improves patient outcomes, reduces microbial resistance, and decreases the spread of infections caused by multidrug-resistant organisms.
