Antibiotics + Resistance Flashcards
what is a bactericidal antibiotic?
one that kills bacteria
what is a bacteriostatic antibiotic?
one that inhibits bacterial growth
what is a narrow spectrum antibiotic?
one that acts on a limited range of bacteria
what is a broad spectrum antibiotic?
one that works on a wide range of gram negative and positive bacteria
what are the three possible methods by which antibiotics work?
acting on the bacterial cell wall
affecting the bacterial ribosomes
acting on bacterial DNA
name three groups of antibiotics that act on the bacterial cell wall
penicillin’s
cephalosporin’s
glycopeptides
what effect does a penicillin have on bacteria?
it inhibits cell wall synthesis
is penicillin bactericidal or bacteriostatic?
bactericidal
how are penicillin’s excreted?
rapidly via the kidneys
what structural feature is found in some penicillin’s?
a beta lactam ring
name five different types of penicillin’s
penicillin flucloxacillin amoxicillin co-amoxiclav tazobactam/piperacillin
what are the three forms of penicillin?
benzylpenicillin
phenoxymethyl penicillin
long acting penicillin
how is benzylpenicillin administered?
IV
what is another name for benzylpenicillin?
penicillin G
what is another name for phenoxymethyl penicillin?
penicillin V
how is phenoxymethyl penicillin administered?
orally
how is long acting penicillin administered?
IM
what two methods of administration can be used for flucloxacillin?
IV and oral
is flucloxacillin broad or narrow spectrum?
very narrow
what organisms can flucloxacillin be used to treat?
gram positive staph and strep only
what methods of administration can be used for amoxicillin?
IV and oral
what can bacteria produce that destroys amoxicillin and why?
beta lactamase, as it destroys the beta lactam ring within it
what methods of administration can be used for co-amoxiclav?
IV and oral
what is co-amoxiclav?
a combination of amoxicillin and clavulanic acid
what is clavulanic acid and what effect does this have on amoxicillin?
a beta lactamase inhibitor
extends the range of bacteria which can be treated with amoxicillin
how is Piperacillin/tazobactam administered?
IV only
what is Piperacillin/tazobactam?
a combination of an antibiotic and a beta lactamase inhibitor
what does Piperacillin/tazobactam treat?
everything besides MRSA infection and ESBL-producing organisms
what does ESBL stand for?
extended spectrum beta lactamases
how do cephalosporins work?
inhibit cell wall synthesis by preventing cross-linking of peptidoglycan
are cephalosporins bactericidal or bacteriostatic?
bactericidal
how are cephalosporins excreted?
via kidneys and urine
are cephalosporins safe in pregnancy?
yes
what structural feature is found in cephalosporins?
a beta lactam ring
are cephalosporins broad or narrow spectrum?
broad
what negative effect can cephalosporins have?
kill off normal gut flora, allowing C.Diff overgrowth
name two glycopeptides
vancomycin
teicoplanin
how do you identify an antibiotic that is a cephalosporin?
has a ceph or cef in its name
how are glycopeptides administered?
IV
how do glycopeptides affect bacteria?
binds to the end of a growing peptide chain in peptidoglycan synthesis,preventing cross linking and weakening the bacterial cell wall
are glycopeptides bacteriostatic or bactericidal?
bactericidal
why do glycopeptides need to be given IV?
they are not absorbed orally
how are glycopeptides excreted?
via the kidneys and urine
what organisms are glycopeptides useful against?
only gram positive bacteria
how do antibiotics that affect protein synthesis work?
they attach to bacterial ribosomes
name the two main groups of antibiotics that affect protein synthesis?
macrolides
aminoglycosides
name three macrolides
erythromycin
clarithromycin
azithromycin
how are macrolides excreted?
via the liver, biliary tract and into the gut
which macrolide is safe in pregnancy?
erythromycin
name an aminnoglycoside
gentamicin
how is gentamicin administered?
IV
is gentamicin bacteriostatic or bactericidal?
bactericidal
how is gentamicin excreted?
via the urine
what is gentamicin active against?
gram negative aerobic organisms i.e. coliforms and pseudomonas
describe the therapeutic index of gentamicin
very narrow, so blood levels must be checked regularly
what can be damaged by aminoglycosides and what can this cause?
kidneys and the 8th cranial nerve
renal failure, deafness and disturbance of balance
name three other antibiotics that inhibit protein synthesis
clindamycin
chloramphenicol
tetracyclines
how are clindamycin, chloramphenicol and tetracyclines excreted?
via the liver and biliary system
what is clindamycin used for?
second line for staph and strep
against true anaerobes
what is chloramphenicol mainly used for?
as a topical treatment for eye infections
are tetracyclines bactericidal or bacteriostatic?
bacteriostatic
name three antibiotics that act on DNA
metronidazole
trimethoprim
fluoroquinolones
what methods of administration can be used for metronidazole?
oral and IV
how does metronidazole work?
causes strand breakage of bacterial DNA
what is metronidazole used for?
infections caused by true anaerobes and protozoa
how is trimethoprim givem?
orally with or without sulphamethoxazole
what is the method of action of trimethoprim?
inhibits bacterial folic acid synthesis
what is trimethoprim given with sulfamethoxazole called?
co-trimoxazole
how is trimethoprim excreted?
in urine
is trimethoprim safe in pregnancy?
yes, from the fourth month onwards
how do fluoroquinolones work?
interact with topoisomerases, preventing replication as the DNA cant uncoil
are fluoroquinolones bacteriostatic or bactericidal?
bactericidal
are fluoroquinolones narrow or broad spectrum?
broad, so their use is restricted to prevent C.Diff infection
what antibiotics can be given orally to treat pseudomonas?
fluoroquinolones
how are fluoroquinolones excreted?
in urine
name two fluoroquinolones
ciprofloxacin
levofloxacin
how is ciprofloxacin administered?
IV or oral
how is levofloxacin administered?
IV only
what is ciprofloxacin used for?
complicated UTI’s
what is levofloxacin used for?
severe CAP in penicillin allergic patients
what side effect can tetracyclines have?
permanent staining of teeth and bones in children under twelve
what side effects can glycopeptides have?
vancomycin damages the kidneys
what does metronidazole interact with?
alcohol
what possible side effects can fluoroquinolones have?
weakened tendons
joint damage in children
seizures
name three antibiotics that should not be given to pregnant women
gentamicin
tetracyclines
fluoroquinolones
what four antibiotics are associated with increased risk for C.Diff infection?
cephalosporins
co-amoxiclav
ciprofloxacin
clindamycin