Flashcards in Misc. antibiotics Deck (46)
What is the MOA of tetracyclines?
REVERSIBLY binds to the 30S ribosomal subunit (inhibits protein synthesis - no binding of tRNA to acceptor site)
Tetracyclines ____________ bind to the 30S subunit while aminoglycosides _______________ bind to the 30S subunit
Are tetracyclines bacteriocidal or static?
STATIC (cidal at high concentrations against susceptible organisms)
What are 3 big MOR for tetracyclines?
1) efflux pumps
2) ribosomal protection proteins
3) enzymatic inactivation
Do you see cross-resistance at all for tetracyclines?
YES but not for minocycline
Which tetracycline is resistant to the MORs?
Describe the spectrum of activity for tetracyclines
GRAM POS: MSSA, PSSP, bacillus, listeria, nocardia
GRAM NEG: burkholderia pseudomallei, neisseria, H. flu
Aerobes: actinomyces, proprionibacterium
MISC: legionella, chlamydophila, chlamydia, mycoplasma, ureaplasma, rickettsia
What are the miscellaneous bacteria covered by tetracylcine
What is a special inclusion and exemption of tigecycline?
OMISSION: proteus and pseudomonas
True or false: tigecycline has pseudomonas activity
FALSE (big hole in activity)
Why can you not use tigecycline for bacteremias or UTIs?
cannot maintain good levels in the blood and does not concentrate in the bladder
What is the route of admin for tigecycline?
What impairs absorption of tetracyclines?
di and trivalent cations
Where is a big site of distribution of tet?
What 3 drugs are not eliminated via the kidney? andwhat 2 are?
renal: tetracycline, demeclocycline
non renal: doxy, mino, tige
what do you use tet/glycylcyclines for?
RMSF, CA pneumo, STDs
What is demeclocycline particularly useful for?
Name 5 adverse effects of tetracyclines
1) GI (nausea and vomiting)
3) PHOTOSENSITIVITY (exaggerated sunburn)
4) renal (fanconi-like syndrome with expired tets)
5) PREGNANCY CAT D
What can you get with expired tet?
fanconi like syndrome (renal failure)
What effects do tetracylcines have on pregnancy?
discoloration of teeth and decreased bone growth
What is the MOA of sulfonamides?
INHIBITS dihydropteroate synthetase (so PABA cannot be incorporated into tetrahydropteroic acid)
Are sulfonamides bacteriocidal or static?
What is the most common short acting sulfonamide?
What does Trimethoprim do?
inhibits dihydrofolate reductase
____________ blocks conversion of PABA ---> dihydrofolic acid while __________ blocks dihydrofolic acid ----> tetrahydrofolic acid
(both result in no purines produced)
Is resistance common to sulfonamides?
YES (structural change of enzyme)
What is the big gram positive and big gram negative bug TMP-SMX targets?
+ = staph aureus
- = stenotrophomonas maltophilia
TMP-SMX is prophylaxis of choice for what bug?
Where do TMP-SMX get good distribution?