What are antibiotics only active against?
What are bactericidal?
Antimicrobial that kills bacteria (penicillins)
What does sensitive mean?
An organism is sensitive if it is inhibited or killed by the antimicrobial available at the site of infection
What is minimal bactericidal concentration (MBC)?
Minimum concentration of antimicrobial needed to kill a given organism
What is bacteriostatic?
Antimicrobial that inhibits the growth of bacteria
What does resistant mean?
Organism is resistant if it is not killed or inhibited by the antimicrobial available at the site of infection
What is minimal inhibitory concentration (MIC)?
Minimum concentration of antimicrobial needed to inhibit the growth of a given organism
What are the routes of antimicrobial administration?
Topical (applied to a surface such as the skin)
Systematic (taken internally, such as orally or parentally)
Parenteral (administered intravenously or intramuscularly)
What is parenteral administeration?
Administered intravenously or intramuscularly
What can antibiotics do to bacteria?
Kill or inhibit it
What are the 3 areas of bacterial metabolic activity that antibiotics can act on?
Inhibition of cell wall synthesis
Inhibition of nucleic acid synthesis
Inhibition of protein synthesis
Why are humans not harmed by antibiotics that inhibit cell wall synthesis?
Human cells do not have cell walls
What bacteria inhibit cell wall synthesis?
How do B-lactams stop cell wall synthesis?
Disrupting peptidoglycans synthesis by inhibiting enzymes (penillin-binding proteins, PBPs) responsible for cross linking the chains
What proteins do B-lactams target?
Penicillin binding proteins (PBPs)
What do glycopeptides act on?
Gram positive bacteria, they are unable to penetrate the wall of gram negative
What are examples of glycopeptides?
How are glycopeptides given and why?
Paternally because they are not absorbed from the GI tract
How do glycopeptides work?
Inhibit cell wall synthesis at a stage earlier than B-lactams, inhibiting the seemble of a peptidoglycan precurser
What do glycopeptides inhibit?
What allows selective action on bacteria protein synthesis?
Differences between bacterial and mammalian ribosomes
What are different classes of drugs used to inhibit protein synthesis?
What do aminoglycans act on?
Gram negative bacteria
How do aminoglycans work?
Insert a different amino acid into the protein
What do macrolides act on?
Gram positive bacteria
What are macrolides an alternative to?
Penicillins for people who are allergic
How do tetracyclines work?
Masks the codon on mRNA so the tRNA cannot bind
What is an example of a oxazolidinone?
How do oxazolidinones work?
Prevents the starting codon on the mRNA to be recognised by tRNA
What is an example of cyclic lippeptide and what does it work against?
Daptomycin which works against gram positive bacteria, MRSA in particular