Antimicrobials Flashcards
Antibacterial soap that target cell wall
Beta lactams
Glycopeptides
Mechanism of action of beta lactams
Bind to penicillin binding protein that forms cross links holding the cell wall together, preventing cell wall synthesis.
Glycopeptides mechanism
Bind to end of cell wall polypeptide chain preventing penicillin binding protein from adding cross links
Examples of antimicrobials that interfere with protein synthesis
Amino glycosides
Tetracycline
Macrolides
Example of antimicrobials that interfere with nucleic acid synthesis
Quinolones
3 mechanisms of drug resistance
Drug inactivating enzyme
Altered target
Altered uptake
Give examples of beta lactams
Penicillin
amoxicillin
Cephalosporins
Carbapenems
Describe coamoxiclav and tazocin
Beta lactams + beta lactams even inhibitors
Strep/staph/anaerobes/gram negs
Give 4antibacterials with anaerobes activity
Coamoxiclav
Tazocin
Carbapenem e.g. Meropenem
Metronidazole
What is used for meningitis
Centriaxone, cephalosporin
Gram neg activity
Good activity in CSF crosses blood brain barrier
What beta lactams used in penicillin allergy
Meropenem
Broadest spectrum
Carbapenem
Activity of glycopeprides
Only Gram positive
Example of glycopeptide
Vancomycin
Treatment of C. difficile
Metronidazole in mild mod
Vancomycin in severe
Not absorbed orally
Treatment of UTI
Tetracyclines
Doxycycline
Trimethoprim (folic acid inhibition)
Treatment of legionella
Tetracycline
Example of amino glycoside
Gentamicin
Macrolide example
Erythromycin
Treatment of H pylori
Triple therapy Azithromycin Cephalosporins Omeprazole Ranitidine
Action of quinolone mechanism
Inhibit DNA topiosomerase and DNA gyrate to prevent supercooling of DNA so there is reduced space for further DNA production
Quinolones action
Gram negative
Example quinolone
Ciprofloxacin
Treatment of influenza
Oseltamivir
Treatment of varicella zoster
Aciclovir
Treatment of candida
Fluconazole
Treatment of malaria
Plasmodium falciparum Quinine artemisinin Vivax, ovale, malariae Chloroquine Primaquine (ROS g6pdd screen)
Targets for antimicrobial action
Cell wall synthesis
Protein synthesis
Nucleic acid synthesis
Membrane function
Treatment of Atypical Pneumonia
Don’t have cell wall so beta lactams don’t work
Macrolides - Clarythromycin
Tetracyclines - doxycycline
Treatment of community acquired pneumonia
Moderate - co-amoxiclav or erythromycin (macrolide)
Severe - Both
Treatment of hospital acquired pneumonia
More likely to be gram negative
Co-amoxiclav
Treatment of pnemonia
Oral/IV fluid Antipyretic Analgesic Antibiotic Oxygen
Treatment of pneumocystis pneumonia
Pneumocystis jiroveci
Cotrimoxazole
How do surface infection microorganisms evade antibiotics?
Formation of biofilm through quorum sensing.
Secrete slime layer in which substances can diffuse and protects the bacteria colony.
Dense extracellular matrix and outer layer of cells protect the interior community.
Allows for spread of antibiotic resistance through quorum sensing.
Lateral gene transfer is greatly increased.
Describe biofilm formation.
Adhesion using pili and fimbriae.
Growth and colonisation.
Quorum sensing to secrete extracellular matrix slime.
Nutrients diffuse into matrix.
Dispersion - biofilm is established and spread occurs.
What is quorum sensing?
Coordination of bacteria in colony based on population density through a series of stimuli and responses. Used to coordinate Biofilm formation Spore formation Resistance Increased virulence
Anaerobic activity
Metronidazole, co-amoxiclav, meropenem, tazocin
