Anti-microbial agents Flashcards
give some examples of types of drugs that inhibit cell wall synthesis
B-lactams
Glycopeptides
Give 3 types of B-lactams
Penicillins
Cephalosporins
Carbapenams
give 2 examples of glycopeptides
Vancomcin
teicoplanin
How are G+ and G- bacteria different
G+ = thick peptidoglycan wall G- = thinner wall but covered in an outer memb - more resistant
What is an issue with drugs that inhibit cell wall synth
only work when bac is growing/spreading - do not have effect on latent inf
what B lactam does not get broken down by B lactamase
Flucloxicillin
what makes up Co-Amox
Amoxicillin + clavulanic acid (B lactamase inhibitor) -> increases coverage
give 2 examples of cephalosporins
ceftriaxone, cefuroxime
what should be used against ESBL prod org
Carbapenams
Give some features of B lactams
renally excreted - dec dose if impaired
do not cross BBB
short half life
broad spec
what interactions should be considered with B alctams
penicillin has 10% cross reactivity with cephalosporins/carbapenms
what type of bacteria are glycopeptides esp effective vs
G+ve - usefull vs MRSA and C. diff
what antibiotic is esp effective vs pseudomonas aureginosa
name + class + method of action
gentamicin
Aminoglycoside - inhib prot synth
how do aminoglycosides work
inhib prot synth - prev elongation of peptide chain and cause mRNA misreading
what are the risks of using aminoglycosides
ototoxic and nephrotoxic - monitor levels
how do tetracyclines work
inhib prot synth
bacteriostatic - prevent bac from reproducing
what is a side effect of using tetracyclines
photosensitivity rash
who should tetracyclines not be given to and why
deposit in growing bone - done give to kids/pregnant women
give 2 examples of macrolides
erythromycin/clindamycin
how do macrolides work
inhib prot synth by interfering with translocation
what are macrolides esp effective against
campylobacter, legionella, pneumophilia
what can be used to treat meningitis if a pt is penicillin allergic
chloramphenicol
what are some important side effects of chrolamphenicol
risk of aplastic anaemia and grey baby syndrome
what are oxazolidonides very active vs
MRSA (G+)
not active vs G-
what are some side effects of oxazolidonides
thrombocytopenia and optic neuritis
give 2 classes of drugs that work by inhibiting DNA synthesis
Quinolones
Nitroinidazoles
how do quinolones work
act vs the alpha subunit of DNA gyrase to inhib DNA synth
name a common nitroinidazole
metronidazole
name a class and example of a drug that work by inhibiting RNA synth
rifamycins - rifampicin
bind to DNA-dependent RNA polymerase
how can you easily check the compliance of rifampicin
will turn secretions orange
give 2 classes of drugs that inhibit folate metabolism
sulphonmides
diaminopyrimidines
what makes up co-trimazole
sulphamethoxalene + trimethoprim
give a common diaminopyramidines and what it is used to treat
trimephoprim - used vs community acquired UTI
what are the 4 ways that a bacteria gains resistance
1 - inactivation of AB/ enzyme chemical modulation
- Reduced accumulation
- Bypass Ab-sensitive step
- Target modification
what method of resistance fo ESBLs have
inactivation of Ab
what mechanism of resistance does MRSA have vs flucloxicillin
target modification/ production of alternate target
encodes novel penicillin binding protein
what is the mechanism of resistance for strep pneumonia vs penicillin
stepwise mut in PBP genes -> req inc concentrations of penicillins
which bac are ESBLs most common in
klebsiella and E. Coli
why would IV administration of an Ab be recommended over oral
if inf is serious/Deep/CNS
or if pt is not absorbing orally (eg sepsis -> drop in BP -> reduced perfusion of intestines)
what are the types of antibiotics in terms of pharmacokinetics
T1 - Conc dendent killing - want C-max as high as possible
T2 - time dependent killing - maximize time above MIC
T3 - mix of 1 and 2 - maximize area under the curve that is over the MIC
give an example of a c. dep killing antibiotic and how it should be given
aminoglycosides - given as big doses to maximize C-max
give some examples of time dependent killing antibiotics and how the should be given
penicillin, cephalosporins, carbapenams
give frequently at lower doses
give some examples of T3 antibiotics that are both concentration and time dependent killers
azithromycin
vancomycin
clindamycin
