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10.19 Antibiotics II
10am by Dr. Figuroa
102
Microbiology
Professional
10/19/2011

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Cards

Term
Which ribosome has the E, P, and A sites?
Definition
large ribosomal subunit
Term
Whata re the three ways antibiotics can inhibit bacterial ribosome function?
Definition
initiation, elongation, misreading
Term
Drugs that act on bacterial ribosomes often have what kind of effect on eukaryotic host?
Definition
mitochondrial toxicity
Term
Describe the characteristics you must take into consideration when administering aminoglycosides.
Definition
concentration dependent killing, post antibiotic effect, follow drug levels, peak= effectiveness, trough = accumulation (renal excretion)
Term
What is the spectrum of aminoglycosides?
Definition
gram - rods NOT anaerobes
gram + cocci in combination
Term
What is the spectrum of streptomycin?
Definition
M. tuberculosis, F. tularenis, Yersinis pestis combination for enterococcus
Term
What are the uses of streptomycin?
Definition
TB, Single agent, combination
Term
What is the spectrum of gentamycin and tobramycin?
Definition
GNR not anaerobes, pseudomonas, combination
Term
What is the spectrum of amikacin?
Definition
resistant GNR
Term
What are the uses of gentamicin and tobramycin?
Definition
blood strem UT, combinations, NOT anaerobic
Term
How do bacteria develop resistance to aminoglycosides?
Definition
enzyme modification, altered ribosomal target, decreased permeability, efflux pump
Term
What are the otoxocity symptoms that can be caused by aminoglycosides? When do these symptoms occur? How?
Definition
auditory and vestibular, idiosyncratic and dose dependent, binds NMDA receptors, reactive oxygen species, mitochondrial toxicity (genetic predisposition--> necrosis or apoptosis
Term
At what doses do you get nephrotoxicity from aminoglycoside agents?
Definition
dose dependent and length dependent; sometimes idiosyncratic
Term
How do aminoglycosides cause nephrotoxicity?
Definition
filtered and binding to proximal tubules, binds megalin, alterations in calcium channels, necrosis or apoptosis due to cationic nature (calcium dependent)
Term
What is the spectrum of linezolid?
Definition
gram positive, especially resistant ones, good lung penetration
Term
Is resistance developing to linezolid?
Definition
ribosome target modification is seen with long-term use
Term
What are the mjoar side effects of linezolid?
Definition
hematologic, neuropathy, and serotonin syndrome
Term
What are the special characteristics of tetracyclines and glycocyclines?
Definition
long acting (doxycycline, minocycline, tigecycline), reversible binding to ribosome, binds metals (teeth, bones), captures photons, broad spectrum activity
Term
How do organisms become resistant to tetracycline?
Definition
efflux pump, ribosome protection (molecules taht have homology for ribosomal proteins, promotes dissociation), modification of molecule (oxidation Tet[x]), modification of ribosome target
Term
What is the spectrum of tetracycline?
Definition
broad spectrum, lots of resistance
Term
What are the characteristics of tetracycline dosing?
Definition
frequent dosing
Term
What is the spectrum of doxycycline?
Definition
broad spectrum, intracellular bacteria
Term
How do you give tetracycline?
Definition
PO
Term
How do you give doxycycline?
Definition
IV/PO
Term
What are the characteristics of doxycycline dosing?
Definition
BID
Term
How do you give minocycline?
Definition
IV/PO
Term
What is the spectrum of minocycline?
Definition
intracellular bacteria and staphylococcus
Term
What are the dosing characteristics of minocycline?
Definition
BID
Term
How do you give tigecycline?
Definition
IV
Term
What is the spectrum of tigecycline?
Definition
broad spectrum, much less resistance, NOT pseudomonas
Term
What are the characteristics of tigecycline dosing?
Definition
BID dosing, binds ribosome more tightly
Term
How does chloramphenicol work?
Definition
binds 50S; block A site
Term
What is the spectrum of chloramphenicol?
Definition
broad spectrum, resistance growing
Term
What are the side effects of chloramphenicol?
Definition
dose-dependent anemia (reversible), and aplastic anemia (irreversible)
** rarely used in this country but frequently in third world (cheap)
Term
How do bacteria become resistant to choloramphenicol?
Definition
chloramphenicol acetyl transferase
Term
How do macrolide/azalide/ketolides work?
Definition
reversible binding to ribosomes based on intracellular concentration
Term
What is the spectrum of macrolide/azalide/ketolide?
Definition
broad spectrum but resistance common among gram - organisms and increasing in gram + organisms
Term
Which antibiotic that targets bacterial protein synthesis is also anti inflammatory?
Definition
macrolide/azalide/ketolide
Term
What are the side effects of macrolide/azalide/ketolide?
Definition
GI, hearing loss (reversible)
Term
What are the mechanisms of resistance against macrolide/ketolide/azalide?
Definition
efflux pumps, altered binding sites (methylation= inducible or constitutive), alteration of tunnel morphology
Term
How do you give erythromycin?
Definition
IV/PO
Term
What is the spectrum of erythromycin?
Definition
respiratory gram +, helicobacter/campylobacter jejuni, mycoplasma, chlamydia, legionella
Term
What are the dosing characteristics of erythromycin?
Definition
QID dosing, GI upset frequent, motilin analogue, resistance increasing
Term
What is the spectrum of clarithromycin?
Definition
respiratory gram +, helicobacter/campy, mycoplasma, chlamydia, legionella + atypical mycobacteria (LESS RESISTANCE THAN ERYTHROMYCIN)
Term
What are the characteristics of clarithryomycin dosing?
Definition
BID dosing
Term
How do you give clarithrymycin?
Definition
PO
Term
How do you give azithromycin?
Definition
IV/PO
Term
What is the spectrum of azithromycin?
Definition
respiratory gram +, helicobacter/campy, mycoplasma, chlamydia, legionella
Term
What are the characteristics of azithromycin dosing?
Definition
single dose STD perscription; daily dosing; long half-life
Term
How do you give telithromycin?
Definition
PO
Term
What is the spectrum of telithromycin?
Definition
same as azithromycin (respiratory pathogens)
Term
What are the dosing characteristics of telithromycin?
Definition
daily dosing, resists efflux, does not induce erm
Term
How does clindamycin work?
Definition
binds in same area as macrolides on a ribosome and turns off toxin production
Term
What is the spectrum of clindamycin?
Definition
gram +, anaerobic (increasing resistance)
Term
How are bacteria resistant to clindamycin?
Definition
clindamycin is resistant to the bacterial efflux pump but NOT to the alteration of ribosome target (inducible erm)
Term
What are the possible side effects of clindamycin?
Definition
C. difficile colitis
Term
Name a type of antibiotic used in animal feeds?
Definition
quino/dalpopristin
Term
Is there an IV formulation of streptogramins?
Definition
yes
Term
What is the spectrum of streptogramins?
Definition
gram +, especially resistant ones (NOT E. faecalis)
Term
Describe resistance to streptogramins?
Definition
efflux, modification of drug, modification of ribosome
Term
What are the side effects of streptogramins?
Definition
myalgia, arthralgia
Term
Ribosome modification of a bacteria can cause multiple resistance to which types of antibiotics?
Definition
macrolides, lincosamides, and streptogramins
Term
How do quinolones work?
Definition
inhibit topoisomerase and gyrase
Term
How does rifampin work?
Definition
inhibits the dissociation of RNA polymerase from sigma factor
Term
How do sulfa and trimethoprim work?
Definition
inhibit the synthesis of folic acid
Term
What must you take into account when giving flouroquinolones?
Definition
concentration dependent, spectrum and toxicity depends on side groups
Term
How do you give flouroquinolones?
Definition
IV/PO formulation
Term
Why are flouroquinolones so popular?
Definition
inexpensive, good tissue penetration
Term
What are the major side effects of flouroquinolones?
Definition
tendon rupture, bone deformities (use care with children), QT prolongation
Term
How are bacteria able to become resistent to flouroquinolones?
Definition
mutations of target enzymes
Term
How do you give ciprofloxacin?
Definition
IV/PO
Term
What is teh spectrum of ciprofloxacin?
Definition
gram neg organisms including pseudomonas
B. anthracis, STDs NOT syphilis
Term
What is the most potent antibiotic against GNR?
Definition
ciprofloxacin
Term
How often do you give cipro?
Definition
BID
Term
How is ciprofloxacin excreted from the body?
Definition
urinary
Term
How do you give Levofloxaxin?
Definition
IV/PO
Term
What is the spectrum of levofloxaxin?
Definition
gram negative > streptococcal, mycoplasma/chlamydia, legionella
Term
How is levovloxaxin excreted?
Definition
urinary excretion
Term
How often do you give levofloxacin?
Definition
daily or BID
Term
How do you give moxifloxacin?
Definition
IV/PO
Term
What is the spectrum of moxifloxacin?
Definition
more potent against G+, less potent against G-, more anaerobes (oral)
Term
How often do you give moxifloxacin?
Definition
daily
Term
Which flouroquinolone has less urinary excretion?
Definition
moxifloxacin
Term
How does trimethroprim-sulfa work?
Definition
two step inhibition: 1) inhibit generation of folinic acid 2) necessary for metabolism
Term
What is the spectrum of trimethoprim sulfa?
Definition
broad aerobic (not strep/not pseudomonas), pneumocystis jiroveci
Term
What are the side effects of trimethoprim-sulfa?
Definition
rash including phototoxicity, erythema multiforme to TEN, renal toxicity/hepatitis, hyperkalemia
Term
Which bacteria is exhibiting increasing resistance to trimethoprim-sulfa?
Definition
e coli
Term
What enzyme is inhibited by sulfa, PAS, and Dapsone?
Definition
dihydro-pterorate synthetase (converts PABA + Dihydro-Pteridine into Dihydropterorate)
Term
What enzyme is inhibited by trimethoprim?
Definition
dihydro-folic acid reductase (dihydrofolic acid into tetrahydro-folic acid)
Term
What is the spectrum of rifampin?
Definition
broad spectrum (staph and mycobacteria)
Term
How does resistance against rifampin occur?
Definition
occurs rapidly if used as a single agent due to enzyme mutation
Term
What are the side effects of rifampin?
Definition
hepatitis, orange secretions/urine, induction of P450
Term
What is the spectrum of metronidazole?
Definition
anaerobes, C. difficile, amoebae (trichomonas, giardia, entamoeba)
Term
How do you give metronidazole?
Definition
oral/IV
Term
T/F Metronidazole has poor tissue penetration
Definition
false, has good penetration
Term
What are the side effects of metronidazole?
Definition
antabuse reaction, neuropathy, dysgeusia (metallic taste), black urine
Term
What is the mechanism of nitrofurantoin?
Definition
unclear; msut be reduced by an enzyme for activity
Term
What is the spectrum of nitrofurantoin?
Definition
(lower UTI infections), many gram -, (not proteus, not pseudomonas), enterococcus
Term
What are the side effects of nitrofurantoin?
Definition
pulmonary infiltrates/fibrosis, eosinophilia
Term
How do you give mupirocin?
Definition
topically
Term
What is the spectrum of mupirocin?
Definition
gram positive esp. Staph
Term
How does mupirocin work?
Definition
binds tRNA-isoleu
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