Antimicrobials Flashcards
various ways antimicrobials work (6)
- disrupt folic acid synthesis
- disrupt DNA topoisomeras
- damage DNA
- disrupt mRNA synthesis
- disrupt protein synthesis
- disrupt cell wall synthesis
classes that disrupt folic acid synthesis (2)
- sulfonamides
2. trimethoprim
classes that disrupt DNA topoisomerase (2)
- fluoroquinolone
2. quinolone
classes that damage DNA (1)
- metronidazole
classes that disrupt mRNA synthesis (1)
rifampin
via RNA polymerase
classes that disrupt protein synthesis @ 50S subunit
- macrolides
- streptogramins
- chloramphenicol
- clindamycin
- linezolid
classes that disrupt protein synthesis @ 30S subunit (2)
- aminoglycosides
2. tetracyclines
classes that disrupt cell wall synthesis via PDG synthesis disruption (1)
- glycopeptides
classes that disrupt cell wall synthesis via PDG cross-linking mess up (6)
- PCNase-sensitive PCN
- PCNase-resistant PCN
- Antipseudomonal PCN
- Cephalosporin (I-V)
- Carbapenem
- Monobactam
examples of sulfonamides (3)
- sulfamethoxazole
- sulfisoxazole
- sulfadiazine
examples of fluoroquinolones (2)
- ciprofloxacin
2. levofloxacin
examples of quinolone (1)
nalidixic acid
example of macolides (3)
- azithromycin
- clarithromycin
- erythromycin
example of streptogramin (2)
- quinupristin
2. dalfopristin
example of aminoglycoside (5)
- gentamicin
- neomycin
- amikacin
- tobramycin
- streptomycin
example of tetracycline (3)
- tetracycline
- doxycycline
- minocyclien
example of glycopeptide (2)
- vancomycin
2. bacitracin
example of PCNase-sensitive PCN (3)
- PCN G
- ampicillin
- amoxicillin
example of PCNase-resistant PCN (3)
- oxacillin
- nafcillin
- dicloxacillin
example of antipseudomonal PCN (2)
- piperacillin
2. ticarcillin
examples of 1st gen ceph
cephazolin
example of 2nd gen ceph
cefoxitin
ex of 3rd gen ceph
ctx
ex of 4th gen ceph
cefipime
ex of 5th gen ceph
ceftraroline
ex of carbapenem (4)
- imipenem
- meropenem
- ertapenem
- doripenem
ex of monobactam (1)
- aztreonam
PCN G vs PCN V difference
G is IV and IM
V is PO
mechanism of PCN G and V
bind PCN-binding protein (transpeptidase) and block cross-linking of PDGN
also activates autolytic enzymes
PCN G, V used against: (5)
bactericidal or lytic?
GP:
- strep pneumo
- strep pyogenes
- actinomyces
- meningococcus
- treponem pallidum
bactericidal
toxicity of PCN G, V (2)
hypersentivity reactions
hemolytic anemia
how do bacteria get resistance to PCN G,V
penicillinase (beta-lactamase) that cleaves the beta-lactam ring of PCN
Ampicillin vs. amoxicillin
they’re both wider spectrum PCN but amoxicillin has greater oral bioavailability
use of ampicillin and amoxicillin vs PCN G, V
they also cover:
- H flu
- E coli
- Listeria monocytogenes
- Proteus mirabilis
- Salmonella
- Shigella
amp and amox HELPSS kill enterococci
mechanism of penicillinase-resistant PCN’s:
oxacillin, nafcillin, dicloxacillin
disrupt cross-linking of PDGN but they also have bulky R group that blacks beta-lactam ring from beta-lactamase
use of penicillinase-resistant PCN
simple staph aureus
not for MRSA
toxicity of penicillinase-resistant PCN (2)
- hypersensitivity reactions
2. interstitial nephritis
toxicity of amipcillin/amoxicillin (3)
- hypersensitivity reactions
- rash
- pseudomembranous colitis
beta-lactamase inhibitors (3)
- clavulanic acid
- sulbactam
- tazobactam
CAST
organisms not covered by cephalosporins? (5)
LAME
- Listeria
- Atypical: mycoplasma
- Atypical: chlamydia
- MRSA (except 5th gen ceph Ceftaroline)
- Enterococci
1st gen ceph
- examples (2)
- covers what (3)
- what’s used before surgery; why?
- cefazolin and cephalexin
- proteus mirabilis
- e. coli
- klebsiella
“PEcK”
- cefazolin used to prevent staph aureus infection
2nd gen ceph
- examples (3)
- covers what (7)
- cefoxitin; cefaclor; cefuroxime
- H Flu
- Enterobacter
- Neisseria spp
- Proteus
- E Coli
- Klebsiella
- Serratia
HEN PEcKS
3rd gen ceph
- examples (3)
what infections
- ceftriaxone; cefotaxime; ceftazidime (cef-T’s)
1. GN infections resistant to other beta-lactams
CTX for meningitis and gonorrhea
Ceftazidime for pseudomonas
4th gen ceph
- examples (1)
- what infection
- cefepime
used for pseudomonas and GP’s
5th gen ceph
- example (1)-
- covers what
ceftaroline
broad spectrum GP and GN including MRSA
BUT does not cover pseudmonas
toxicity of cephalosporins (3)
- hypersensitivity reactions
- vitamin K def
- increased nephrotoxicity of aminoglycoside
monobactam
- example
- toxicity
- aztreonam
- usually nontoxic; just some GI upset
aztreonam
- mechanism
beta-lactamase resistant abx
aztreonam synergistic with what
aminoglycoside
aztreonam used against
- what situations
GN rods only
no activity against GP or anaerobes
used in pts with PCN-allergy and pts with renal insufficiency who cannot tolerate aminoglycoside
carbapenem mechanism
beta-lactamase resistant abx
carbapenem always given with what? why?
cilastatin
inhibits renal dehydropeptidase I to prevent it from becoming inactivated in renal tubules
carbapenem use (3 general classes)
GP cocci
GN rods
anaerobes
toxicity of carbapenem (3)
- GI distress
- skin rash
- CNS: seizure
vanco mechanism
binds D-ala D-ala of cell wall precursoors
bactericidal
vanco use
GP only
- MRSA
- enterococci
- c. dif
vanco toxicity (3)
- nephro
- oto
- thrombophlebitis
how do bacteria become resistant against vanco?
D-ala D-ala —> D-ala D-lac
30S inhibitors
aminoglycosides (bactericidal)
tetracycline (bacteristatic)
buy AT 30
50S inhibitors
chloramphenicol
clindamycin
macrolides (erythromycin)
linezolid
CCEL at 50
what abx prevents ribosomes from even finding mRNA
linezolid
which abx prevents initiation complex formation
aminoglycosides
what abx prevents peptidyl transferase
chloamphenicol
what abx prevents translocation of ribosome in translation? (2)
Macrolides
Clindamycin
what abx prevents A-site tRNA binding
Tetracycline
what abx are bateristatic
all protein synthesis inhibitors except for aminoglycosides, which are bactericidal
which abx needs O2 for uptake?
aminOglycOsides 2Os, O2
What bugs covered by aminoglycoside?
severe GN rod infections
synergistic with beta-lactams
which aminoglycoside is used for bowel surgery?
neomycin
toxicity of aminoglycoside (4)
- nephrotoxicity (esp if with cephalosporin)
- ototoxicity (esp if with loop diuretics)
- NMJ blockade
- teratogen
how bacteria become resistant to aminoglycosides
bacterial transferase enzyme inactivates drug by transferring acetyl, phosphate, adenyl group
aminoglycoside mechanism
prevents initiation factor for translation
tetracyclin mechanism
prevents attachment of amino-acyl tRNA
what should you avoid when on tetracycline?
dairy or antacaids b/c Ca and Mr inhibit absorption in gut
use of tetracyclines (4)
- borrelia burgdorferi (doxycycline)
- m. pneumoniae
- rickettsia
- chlamydia
why can we use tetracyclines for rickettsiae and chlamydia even though they’re intracellular bugs
it accumulates intracellularly
tetracyclin toxicity (4)
- GI distress
- teeth and bone bad
- photosensitivity
- teratogen
how bacteria become resistant to tetracycline
decrease uptake and increase efflux using plasmid-encoded transport pumps
mechanism of macrolide
blocks translocation during sliding of ribosome
“macroSLIDES”
use of macrolides (3)
- atypical PNA (mycoplasma, chlamydia, legionella)
- STD (chlamydia)
- GP cocci (strep infections in pts w/PCN allergies)
macrolide toxicity (6)
MACRO
- motility issues
- arryhthmias (QT prolongation)
- cholestatic hepatitis
- rash
- eOsinophilia
- increases concentration of tehophylline and warfarin
how bacteria become resistant to macrolides
they methylate 23S rRNA -binding site to prevent drug from binding to it
mechanism of chloramphenicol
blocks peptidyltransferase at 50S
use of chloramphenicol 2)
- meningitis (h flu, neisseria, strep)
2. rocky mountain spotted fever (ricketsseiae rickettsii)
chloramphenicol toxicity (3)
- anemia
- aplastic anemia
- gray baby syndrome (in premies b/c they lack UDP-glucoronyl transferase)
how bacteria become resistant to chloramphenicol
plasmid-encoded acetyltransferase inactivates it
mechanism of clindamycin
blocks translocation at 50S
Clinda uses (4)
- anaerobic infections (bacteroides, c perfringens) in aspiration PNA
- lung abscess
- oral infections
- GAS
what treats anaerobes above the diaphragm
what treats anaerobes below the diaphragm
above: clinda
below: metro
clinda toxicitiy (3)
psuedomembranous colitis (c difficile)
fever
diarrhea
sulfonamide mechanism
inhibits folate synthesis
use of sulfonamides (5)
- GP
- GN
- nocardia
- chlamydia
- UTI
sulfonamide toxicity (6)
- hypersensitivity reaction
- hemolysis if G6PD def
- nephrotoxicity (tubulointerstitial nephritis)
- photosenstiive
- kernicterus in infants
- displace warfarin from albumin
how bacteria become resistant to sulfonamides
decresae uptake
increase PABA synthesis
alter enzyme needed to make DHF
trimethoprim mechanism
inhibits bacterial DHF reductase
trimethoprim use
ppx in pneumocystis PNA, toxo
also in UTI, shigella, salmonella
trimethoprim toxicity (3)
- megaloblastic anemia
- leukopenia
- granulocytopenia
fluoroquinolone mechanism
inhibit DNA gyrase (topo II) and topo IV
fluoroquinolone use
GN rods of GU and GI
pseudomonas, neisseria
some GPs
fluoroquinolone toxicity
- Gi upset
- rash, h/a dizzy
- tendonitis w/ tendon rupture
- leg cramps and myalgias
- teratogen
- arrhyhtmia
TERRIBLE
how bacteria become resistant to fluoroquinolone (2)
chromosome encoded mutation in DNA gyrase
plasmid can also code for efflux pumps
metronidazole mechanism
free radical metabolites damage DNA
use of metronidazole (6)
GET GAP
- giardia
- entamoeba
- trichomonas
- gardnerella vaginalis
- anaerobes (bacteroides, c diff)
- pylori (H pylori) triple therapy
metronidazole toxicity (3)
- disulfiram-like reaction (flushing, tachy, hypotension) with alcohol
- h/a
- metallic taste
anti mycobacterium tuberculosis drug
- ppx
- tx
ppx: INH
tx: RIPE - rifampin, INH, pyrazinamide, ethambutol
anti mycobacterium avium-intracellulare drug
- ppx
- tx
ppx: azithromycin and firabutin
tx: azithro/clarithro + ethambutol … can add rifabutin or cipro too
anti mycobacterium leprae
- ppx
- tx
ppx: none
tx: long-term dapsone and rifampin for tuberculoid form
add clofazimine for lepromatous form
INH mechanism
decrease synthesis of mycolic acid
what does bacteria need to have for INH to become activated
bacterial catalase-peroxidase
INH toxicity (2)
- nephro
2. hepato
what can be given with INH to prevent neurotoxitity and possible drug-induced lupus
vitamin B6 (pyridoxine)
examples of rifamycin (2)
- rifampin
2. rifabutin
rifamycin mechanism
inhibits DNA-dep RNA polymerase
use of rifamycin (4)
- mycoTB
- delays resistance to dapsone when used for leprosy
- ppx for meningogoccus
- ppx for h flu
tifamycin toxicity (3)
- minor hepatotoxicitiy
- increase cyt p450
- orange body fluids (nonhazardous)
rifampin or rifabutin has less cyt p-450 stimulation … therefore, which one used more for HIV infection
rifabutin
pyrazinamide mechanism
uncertain… effective in acidic environment of phagolysosome where TB resides in macrophages
pyrazinamide toxicity (2)
- hyperuricemia
2. hepato
ethambutol mechanism
decrease carb polymerization of myco cell wall by blocking arabinosyltransferase
ethambutol toxicity (1)
optic neuropathy (red-green color blindness)
abx for endocarditis w/surgical or dental procedures
PCN
abx for gonorrhea
ctx
abx for h/o recurrent UTIs
TMP-SMX
abx for meningococcal infetion
ciprofloxacin in adults
rifampin in chidlren
abx for pregnant woman with GBS
ampicillin
abx for prevention of gonorrheal or chlamydial conjunctivitis in newborn
erythromycin
abx to prevent post surg infection with staph aureus
cefazolin
abx for ppx of strep pharyngitis in child with prior rheumatic fever
oral PCN
abx for syphilis
benzathine PCN G
in HIV w/ < 200 CD4, what infection risk?
- what abx for ppx?
pneumocystis PNA
TMP-SMX
in HIV w/ <100 CD4, what infection risk?
what abx for ppx
pnuemocystis PNA
Toxo
TMP-SMX
in HIV w/<50 CD4, what infection risk
what abx for ppx
mycobacterium avium
azithromycin
abx for MRSA (5)
- vanco
- linezolid
- tigecycline
- ceftaroline
- daptomycin
abx for VRE(2)
- linezolid
2. streptogramin
abx for pseudomonas (6 classes:12 abxs)
- PCN: piperacillin; ticarcillin
- cephalosporin: ceftazidime (3); cefepime (4)
- aminogylcoside: amikacin, gentamicin, tobramycin
- fluoroquinolones: ciprofloxacin, levofloxacin
- monobactam: aztreonam
- carbapenem: imipenem, meropenem
various ways anti-fungals work (5)
- inhibit cell wall synthesis
- forms membrane pores
- inhibit nucleic acid synthesis
- inhibit lanosterol synthesis
- inhibits ergosterol synthesis
ex of fungal cell wall synthesis inhibitors class and (3)
Echinocandins:
- caspo.fungin
- mica.fungin
- anidula.fungin
ex of fungal membrane pore formers class and (2)
Polyenes
- amphotericin B
- nystatin
ex of fungal nucleic acid synthesis inhibitors (1)
5-Flucytosine
ex of lanosterol synthesis inhibitors (1)
Terbinafine
ex of ergosterol synthesis inhibitors class and (6)
Azoles
- fluconazole
- ketoconazole
- clotrimazole
- miconazole
- itraconazole
- voriconazole
Amphotericin B mechanism
binds to ergosterol (fungal MB lipid) and makes a pore to leak electrolytes
use of amphotericin B (7)
- serious systemic mycoses
- cryptococcus
- blastomyces
- coccidiodes
- histoplasma
- candida
- mucor
intrathecal for fungal meningitis
what do you need to give also when giving amphotericin B? why?
K and Mg
altered renal tubule permeability
amphotericin B toxicity (6)
- f/c
- hypotension
- nephro
- arrhythmias
- anemia
- IV phlebitis
nystatin mechanism
makes a pore in fungal MB
nystatin difference from amphotericin B
it’s the topical version
nystatin use (3)
- oral candida
- diaper rash
- vaginal candidiasis
mechanism of Azoles
inhibit fungal ergosterol synthesis by inhibiting cyt p450 enzyme that converts lanosterol to ergosterol
use of Azoles
- local and less serious systemic mycoses
- fluconazole for suppression of cryptococcal meningitis in AIDS and all candida
- itraconazole for Blastomyces, coccidiodes, histoplasma
- clotrimazole and miconazole for topical fungal infections
itraconazole for what? (3)
blastomyces
cocciciodes
histoplasma
Azole toxicity (2)
- gynecomastia (2/2 testosterone synthesis inhibition)
2. liver dysfunction (2/2 inhibit cyt-p450)
5-Flucytosine mechanism
inhibtis DNA and RNA biosynthesis by conversion to 5-fuorouracil by cytosine deaminase
5-flucytosine use (1)
- systemic fungal infection (esp cryptococcus meningitis) in combo with amphotericin B
cryptococcus meningitis antifungals
5-flucytosine with amphotericin B
5-Flucytosine toxicity
BM suppression
Echinocandin mechanism
inhibit cell wall syntehsis by inhibiting syntehsis of beta-glucan
Echinocandin use (2)
- invasive aspergiloosis
2. candida
Echinocandin toxicity (2)
- GI upset
2. flushing (2/2 histamine release)
Terbinafine mechanism
inhibits fungal enzyme squalene epoxidase –> prevents formation lanosterol and ultimately ergosterol
Terbinafine use
- dermatophytoses (esp onychomycosis - fungal infection of toenails or finger nails)
what is onychomycosis
fungal infection of toenails and finger nails
Terbinafine toxicity (4)
- GI upset
- taste disturbance
- hepatotoxitiy
- h/a
Griseofulvin mechanism
interferes with microtubule function - disrupts mitosis
Griseofulvin deposits where?
keratin-containing tissues (nails)
Griseofulvin use (2)
- oral Tx of superficial infections
2. inhibits growth of dermatophytes (tinea, ringworm)
Griseofulvin toxicity (5)
- teratogen
- carginogen
- confusion
- h/a
- increase p-450 and warfarin metabolism
Antiprotozoan therapy ex (5)
- Pyrimethamine
- suramin
- melarsoprol
- nifurtinmox
- sodium stibogluconate
tx for toxo
pyrimethamine
tx for trypanosoma brucei
suramin and melarsoprol
tx for trypanosoma cruzi
nifurtimox
tx for leishmaniasis
sodium stibogluconate
chloroquine mechanism
blocks detoxification of heme into hemozin –> heme accumulates and is toxic to plasmodia
antihelminth therapy ex (5)
- mebendazole
- pyrantel pamoate
- ivermectin
- diethylcarbamazine
- praziquantel
what to use against flukes (trematodes)like Schistosoma
praziquantel