Antibiotics I Flashcards
antibiotics are produced by _____ that kills or inhibits growth of other opportunistic microorganisms
microorganisms
what is an indicator of an antibiotic drug’s selectivity?
therapeutic index
pathogen specific and has a rapid response for sensitive organisms
narrow spectrum
better for mixed infections, has gram + and gram - coverage, but may give up some effectiveness for gram + to gain effectiveness for gram -
broad spectrum
since narrow spectrum antibiotics can target one or two bacteria, they will produce ____ _____ _____.
less side effects
what are broad spectrum antibiotics good for?
empiric coverage
why do broad spectrum antibiotics lead to super-infection?
they alter normal gut flora = allow more pathogenic organisms an opportunity to survive
what spectrum antibiotics are preferred if bug is susceptible/sensitive?
narrow spectrum
what will gram + stain look like?
blue
what are 3 examples of gram + cocci?
staph
strep
enterococcus
what will gram - stain look like?
pink
what are 2 examples of gram - cocci?
neisseria
h. flu
name the bacteria that is highly adaptive to surrounding environment
pseudomonas aeruginosa
what are the bacteria-lacking cell wall called?
intracellular (atypical)
4 beta lactam antibiotic classes that are cell wall inhibitors
Penicillins
Cephalosporins
Monobactam
Carbapenems
3 antibiotics that are cell wall inhibitors, but not beta-lactams
Bacitracin
Cycloserine
Vancomycin
medication that inhibits RNA transcription. what is it used for?
Rifampin
treats TB
6 drug classes that inhibit protein (ribosome) synthesis that is necessary for bacterial growth
MALT-SO
Macrolides
Aminoglycosides
Lincosamides
Tetracyclines
Streptogramins
Oxazolidinones
what kind of antibiotics penetrate the cytoplasmic membrane integrity of the bacteria?
peptide antibiotics
what antibiotic medication inhibits nucleotide biosynthesis of bacteria?
trimethoprim-sulfamethoxazole
what class of antibiotics inhibit topo-isomerase?
fluoroquinolones
which antibiotic inhibits DNA replication of bacteria?
metronidazole
when bacteria goes under a change to become resistant
vertical mutation/resistance
when bacteria gets a resistant gene from an already-resistant organism
horizontal mutation/resistance
DNA and plasmids carrying the resistant gene transferred directly from resistant to susceptible bacteria. which gram bacteria use this?
conjugation
gram -
DNA and plasmids transferred via a bacteriophage (virus infects bacterium, replicates, and incorporates resistant gene). which gram bacteria use this?
transduction
gram +
DNA and plasmids acquired from environment (released by dead bacteria). which gram bacteria use this?
transformation
gram +
what gram bacteria is more worrisome? why?
gram -
less work is required for it to become resistant
drugs that act on targets that are essential for bacterial survival
bactericidal
what kinds of drugs are considered bactericidal? (2 MOAs and 1 drug class)
cell wall synthesis inhibitors
DNA synthesis inhibitors
aminoglycosides
drugs that act on targets that are necessary for bacterial growth, but not survival
bacteriostatic
what kinds of drugs are considered bacteriostatic? (3)
protein synthesis inhibitors
sulfonamides
trimethoprim
linezolid
linezolid is bacteriostatic against what? (2)
staph aureus
enterococcus
linezolid is bactericidal against what? why?
strep pneumo
strep is not as resistant (it’s stupid)
between strep and staph, which is more resistant?
staph
smallest amount of antibiotic needed to inhibit the growth of bacteria
minimal inhibitory concentration
which 2 antibiotic classes are concentration-dependent killing?
aminoglycosides
fluoroquinolones
which 4 antibiotic classes are time-dependent killing?
“Bedtime Varies, Morning Comes”
Beta-lactams
Vancomycin
Macrolides
Clindamycin
how should a concentration-dependent killing antibiotic be administered?
dose once a day
how should a time-dependent killing antibiotic be administered?
dose more frequently so concentration is always above the MIC
since gram + bacteria has a huge cell wall that covers the penicillin binding protein, what kinds of antibiotics are important to use?
cell wall inhibitors
why don’t gram - bacteria respond well to beta lactams?
because gram - bacteria contain a beta-lactamase that destroys beta lactam rings
which 2 drug classes bind to penicillin-binding proteins on the cell membrane to inhibit the last step of cell wall synthesis and weakens the cell wall?
penicillins
cephalosporins
narrow spectrum PCN used to treat staph and strep
penicillin-v
broad spectrum PCNs used to treat gram +, gram -, and gram - anaerobes (2)
amoxicillin
ampicillin
what do all bacterial cell wall inhibitors in beta lactam category contain?
beta lactam ring structure
what is a beta lactam ring structure essential for?
bactericidal activity
how does staph produce beta-lactamases (penicillinase); AKA enzymes for resistance?
via altered penicillin-binding-proteins
where are penicillins distributed to?
most body fluids (bile, serum, synovial fluid)
where do penicillins have poor penetration? (2)
bone
cerebrospinal fluid (unless inflamed meninges)
how are penicillins elminated?
renal elimination
since penicillins have a high TI, which patients can actually receive it? (2)
pregnancy
lactating
what are the 4 main ADR of penicillins?
Neurotoxic
Abdominal pain
Skin rash/Seizure
Throat closure
Yacking (vomitting)
Diarrhea (C. difficile)
what kind of penicillins cause concern for C. difficile (super-infection)?
broad spectrum penicillins
when does neurotoxicity occur in penicillins? (2)
high dose
intrathecal administration (CSF)
which penicillin has a high risk of interstitial nephritis?
methicillin
what should be avoided in patients with history of severe allergies to PCNs? why?
all beta-lactam antibiotics with a R-side chain
body forms IgE to penicillic acid (reactive metabolite)
which PCN has poor oral absorption because it is acid-labile?
PCN G
which PCN has good oral absorption because it is stable in gastric acid?
PCN V
what characteristics make PCN a broad spectrum? (2)
increased water solubility
increased membrane penetration
which amino-penicillin has a better bioavailability?
amoxicillin
what is the amoxicillin used as first line treatment for?
sub-acute bacterial endocarditis prophylaxis
what PCN is the only one still used for pseudomonas aeruginosa? what is the administration route?
piperacillin
IV
what is the main characteristic of anti-staph penicillins?
stable against beta-lactamase
what are the 3 PCNs that are combined with a beta-lactamase inhibitor?
amoxicillin/clavulanic acid (augmentin)
ampicillin/sulbactam (unasyn)
piperacillin/tazobactam (zosyn)
which PCN + beta-lactamse inhibitor combo has better bone penetration?
piperacillin/tazobactam (zosyn)
what is the use for PCN combined with B-lactamase inhibitor? (3)
severe intra-abdominal infections
severe soft tissue infections
anaerobes
what are the 1st generation Cephalosporins?
what do they treat?
cephalexin
cefazolin
MSSA (staph)
strep
which cephalosporin is a good alternative in questionable or mild PCN allergies (rash)?
1st gen cefazolin
which generation cephalosporins are used for anaerobes and gram -?
2nd generation (cefotetan + cefoxitin)
2nd generation Cephalosporins (cefotetan + cefoxitin) are first line prophylactic treatment for …..
intra-abdominal surgery prophylaxis
which is the only approved “anti-MRSA” cephalosporin in the US?
ceftaroline
what specific organisms is ceftaroline used for?
MRSA
PRSP (penicillin-resistant staph pneumo)
which cephalosporine generation/drug has good gram + and gram - coverage?
4th generation
cefepime
what are the 2 uses of 4th gen cephalosporin cefepime?
anti-pseudomonal
critically ill patients
which organism cannot be covered with any cephalosporin?
enterococcus
how are cephalosporins excreted?
kidney
what are 3 ADR of cephalosporins?
GI
hypersensitivity
super-infection
which cephalosporin generations have a cross-reactivity with penicillins?
1st gen
2nd gen
a patient taking a cephalosporin begins to experience N/V, flushing, tachycardia, headache, and sweating. what is this reaction called and what likely caused it?
disulfiram-like reaction
alcohol use
a patient taking a cephalosporin presents with bleeding. what caused this? what generation cephalosporin could they be taking?
inhibited vitamin K carboxylase = low clotting factors
2nd/3rd generation
which medication interacts with some 2nd and 3rd generation cephalosporins? what can the use of both together lead to?
warfarin
bleeding
a patient is taking a penicillin and presents with hypoprothrombinemia. what could they be taking?
piperacillin + CPH
which cell wall inhibitor is promoted as “non-nephrotoxic replacement for AMG”?
aztreonam
what does Aztreonam cover? (2)
gram -
pseudomonas
a patient presents with a severe gram - infection but is allergic to PCN, CPH, and carbapenems. what can they receive as treatment?
aztreonam (cell wall inhibitor)
how is aztreonam excreted?
renal tubules (kidney)
which class does aztreonam have cross resistance with?
especially with which drug?
3rd + 4th gen cephalosporins
ceftazidime
-penem
carbapenems (cell wall inhibitors)
how are carbapenems excreted?
kidney
why does imipenem need to be combined with cilastatin?
cilostatin inhibits dehydropeptidase that causes nephrotoxicity
what is an ADR of imipenem?
seizure
which medication do carbapenems decrease, specifically imipenem?
valproic acid for seizures
which carbapenem has the narrowest spectrum and long half life?
ertapenem
why are carbapenems considered the atomic bomb of antibiotics?
they have the broadest spectrum of all beta-lactams
how do carbapenems work against carbapenemase?
add a beta-lactamase inhibitor
which gram + bacteria is not covered by Carbapenems?
enterococcus
which beta-lactams are good for serious gram - infections and meningitis? (3)
broader spectrum PCN
3rd gen CPH
4th gen CPH
what do many use cefazolin for? and why?
surgical prophylaxis
least irritating for IM + good bone penetration
what are carbapenemas restricted for?
severe infections in hospital
name the 2 glycopeptides and their MOA
vancomycin
telavancin
inhibits late step of cell wall synthesis
what are the uses for vancomycin (glycopeptide)? (2)
gram +
c. difficile
how is vancomycin excreted?
kidney
what are 5 ADR to remember for vancomycin?
Nepthrotoxicity
Ototoxicity
Red man syndrome
Tissue necrosis if IM
corn protein allergy
when can vancomycin cause nephrotoxicity and ototoxicity?
when used with AMG
how does vancomycin cause red man syndrome?
releases histamine based on infusion rate
a glycopeptide that has large nephrotoxicity, interferes with coag test, not recommending in pregnancy, increased QT interval, and interacts with fluoroquinolones, macrolides, and antipsychotics
telavancin
polypeptides that inhibit cell wall synthesis (2)
fosfomycin
bacitracin
which polypeptide works for gram + and gram -, and is used for UTI?
fosfomycin
what is the dosing for fosfomycin? why?
once daily
high TI
what are the ADR of fosfomycin?
GI
headache
which polypeptide works for gram + only and is used for eye and skin infections via topical?
bacitracin
why isn’t bacitracin used systemically?
causes renal necrosis
cell membrane destabilizer that is bactericidal and narrow for gram + only
daptomycin
what is the use for daptomycin?
vancomycin-resistant organisms
what are 3 ADR of daptomycin?
myopathy
rhabdo
eosinophilic pneumonia
if a patient is taking a statin, which antibiotic could cause myopathy and rhabdo?
daptomycin
