Antibac/antifungal agents Flashcards
define these terms: antibiotics antimicrobial agent bacteriostatic/fungistatic bactericidal/fungicidal
chemical products of microbes that inhibit or kill other organisms
encompasses antibiotics and synthetic compounds and semi synthetics
inhibit growth eg protein synthesis inhibitor
kill organism eg penicillins
define these terms: Minimum inhibitory concentration (MIC) minimum bacterial/fungical conc (MBC/MFC) synergism antagonism indifference antimicrobial spectrum
min conc at which visible growth is inhibited eg low MIC means sensitive organism
min conc needed to kill organism
activity of 2 antimicrobials given together is greater than the sum of their activity if given separately
one agent diminishes activity of the other
activity is unaffected by the addition of another agent
range of organisms likely to be sensitive to a type of agent
what is the issue with broad spectrum antibiotics
kill natural flora
what are the two types of mechanisms of action of antimicrobial agents
inhibit enzymes and physical structures
exhibit selective toxicity to target
what are the 5 specific antimicrobial targets
cell wall protein synthesis DNA synthesis RNA synthesis Cell membrane
what is targeted in bacterial cell walls
peptidoglycan
what is targeted in fungal cell walls
B 1 - 3 glucan
what are some antibacterial cell wall inhibitors
B lactams: (traget transpeptidases) penecillin Cephalosporins Carbapenems monobactams
glycopeptides - tigecycline
(inhibit binding of transpeptidases and stops cross linking) - used for MRSA
what is an anti fungal cell wall inhibitor
echinocandins
inhibit B 1 3 glucan synthase
describe some examples of antibacterial protein synthesis targets
aminoglycosides - binds to 30S subunit ribosome
M.L.S. antibiotics
Tetracyclines - doxycycline for MRSA - bind to 30S sub unit
oxazolidnones - bind 50S sub unit
Mupirocin or fusidic acid
why are there not antifungals that target protein synthesis
same mechanisms as humans so would be toxic
describe some antibacterial DNA synthesis drugs
trimethoprim - inhibits folate synthesis (UTIs) via inhibits reductase
sulphonamides - same but via inhibit synthetase
quinolones/fluroquinolnes
what is an example of a DNA synthesis anti fungal target
5 flurocytosine - not very effective
what is a antibacterial RNA synthesis drug
firfamycin - RNA polymerase inhibitor
what are some antibacterial cell membrane drugs
colistin for gram +
daptomycin
