Antimicrobial Chemotherapy Flashcards
Beta Lactams Include
Penicillins, cephalosporins and cephamycins
Penicillin is produced by the fungus
Penicillium chrysogenum
Beta Lactam Mechanism of Action
Binds irreversibly to enzyme that cross link the cell wall - so cell wall is weak and cell cannot manage osmotic pressure so leads to cell lysis
Differences between pencillin, cephalosporins and cephamycin
cephalosporins and cephamycin have dihydrothiazine ring - penicillin does not have this
cephamycin has methoxy group - other two does not.
why does cephalosporins and cephamycin more effective in killing of bacteria than penicillin?
because they have semi-synthetic so are more resistant to enzymes that hydrolyse them
Aminoglycosides - streptomycin, kanamycin, neomycin, gentamycin - most effective against?
works well against gram positive and anaerobic gram negative bacteria
Aminoglycosides - mechanism of action
inhibits 30S ribosomal unit and prevents synthesis of proteins
Macrolides - erythromycin and clarithromycin
large lactone rings and effective against gram positive bacteria - used for patents allergic to penicillin
Macrolides are good at treating…
mycoplasma and mycobacteria
Macrolides mechanism of action
inhibit the 50S ribosomal subunit and prevents protein synthesis
Tetracyclines - tetracycline, doxycycline
Tetracene ring - inhibits 30S ribosomal subunit
Quinolones - ciprofloxacin and moxifloxacin
Inhibit DNA unwinding so prevents replication of DNA
Sulfa Drugs - Sulfanilamide and sulfadiazine
Inhibits folic acid synthesis - not toxic to human cells as they intake folic acid through diet rather than producing it
growth factor and nucleic acid analogues
Growth factor analogues prevent against microbial growth
Nucleic acid base analogues are formed by adding Br F and they interfere with DNA synthesis
Antibiotic Use in Humans
Penicillins 58.4%
Macrolides 11.8%
Tetracyclines 8%
Others 18.3%
