Antibiotics Flashcards
What are antimicrobials?
a broad category of agents that are used to treat or prevent infections caused by microorganisms
What are antibiotics?
specific class of antimicrobial that specifically target bacteria.
Three types of antibiotics?
Bacteriostatic, bactericidal, bacteriolytic
Bacteriostatic drugs?
Prevent growth of microorganism
Bactericidal drugs?
Kill microorganisms
Bacteriolytic drugs?
Lyse–> break down/degreade the microoganism
What happens to the OD after bacteriostatic antibiotics are added and why?
SLight increase–> could be due to size of cells increasing, or metabolic products contributing to it
What happens to the OD after bactericidal antibiotics are added and why?
Constant–> bacteria are not fragmented and so are still there
What happens to the OD after bacteriolytic antibiotics are added and why?
Drops–> bacteria fragments
Example of a bacteriolytic antibiotic?
Lysozyme
How does a lysozyme work?
Catalyses hydrolysis of B1-4 glycosidic links in the cell walls peptidoglycans
Cell bursts bc of osmotic pressure
Why was drug selectivity developed for antibiotics and an example?
So they could target bacteria but not humans
e.g. cell wall
What is the bacterial cell wall made up of?
Peptidoglycan
What is the fungal cell wall made up of?
Chitin
Examples of cell wall synthesis inhibitors?
Penicillin, glycopeptides, cephalosporins, carbapenems
PGCC
Nucleotide synthesis inhibitor example?
Sulphonamides
FOSul
DNA rep inhibitors?
Quinolones
QUINrep
Protein synthesis inhibitor example?
Macrolids, aminoglycosides, lincosamides, tetracyclines
MALT
How does penicillin work?
Make existing peptidoglycan wall weaker–> cell bursts as a result of osmotic pressure
What do sulphonamides target?
Folic acid DNA precursors
Which protein synthesis inhibitors target the 30S subunit?
Tetracyclines and aminoglycosides
What does vancomycin rpevent?
Formation of the peptidoglycan layer
What part of cell wall inhibitors is the functional unit?
Beta-Lactams
How does the beta lactam ring work?
Mimics the D-Ala AAs of the peptidoglycan wall that
Binds to transpeptidase enzyme instead
Cell wall is v weak as the bonds between the AA chains are not made
How did bacteria acquire resistance to beta lactam-containing antibiotics?
They developed beta lactamases
What is the “last resort” class of antibiotics?
Vancomycin
Issue with vancomycins?
Can cause nephron toxicity
What infections can cell wall inhibitors treat?
Bone and joint, respiratory, UTI, skin, heart, meningitis
How does sulfonamides target folic acid precursors?
Prevent formation of dihydrofolic acid from pteridine and PABA by inhibiting dihydrofolate synthase
