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76 Cards in this Set
- Front
- Back
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how do sulfonamides work (antimetabolites)
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competitively inhibit folic acid and inhibit DNA synthesis
analog of PABA bacteristatic (reversible) |
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inhibits the production of folic acid by competitive inhibition?
what infection is it used for |
sulfonamides
used for UTIs cause it is conc in urine |
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sulfonamides - bacteriocidal or static
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static
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some of these antibiotics are concentrated in urin and so their greates application is in treating UTIs
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Sulfonamides
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inhibits dihydrofolate reductase
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trimethoprim
an antimetabolite. often used in conjunction with sulfonamide (BACTRIM) |
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narrow spectrum antibiotic.
antimetabolite works against M. tuberculosis by interfering with the sythesis of mycolic acid (material unique to the cell walls of mycobacteria) |
isoniazid
antimetabolite (inhibits enzyme termed InhA needed for fatty acid elongation) |
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isoniazid - cidal or static
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cidal - penetrates well through human cell membrane to fight M. tuberculosis
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how does penecillin work
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inhibits cell wall synthesis
by binding PBPs (many are responsible for the terminal stages of cell wall synthesis e.g transpeptidazes) inactivation of PBPs trigger autolytic enzymes to break down cell wall |
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this class of antibiotics inhibits peptidoglycan synthesis
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cell wall inhibitors
uncouples the control of endogenous degradative activities (autolysins) which normally are synchronized with cell wall synthesis - cell lysis in hypotonic media |
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A Penicillin which is hydrolyzed by acidity of stomach, is sensitive to penecillinase and has benzyl side chain on 6-amino-penicillanic acid
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penicillin G
works against G+, some G- |
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penicillin which is NOT sensitive to acid hydrolysis but IS sensitive to penicillinase and has a phenoxymethyl side chain
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Penicilin V
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not sensitive to acid hydrolysis but still sensitive to penicillinase with an aminobenzyl side chain
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ampicillin
broader specturm the P G and V. works against G- enteric Bacilli, and G+ |
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B lactam antibiotics are structural analogs of?
and bind what? |
analogs of pepotidoglycan pentapeptide
bind penicillin-binding proteins (PBPs e.g transpeptidase) |
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sensitive to penicillinase - limited spectrum - highest activity against Gm+ bacteria and G- cocci; ineffective versus Gm- enterics
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Penicilin G and V
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sensitive to penicillinase - broader spectrum (active against G- enteric bacilli as well as retaining most activity against G+)
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ampicillin
amoxiciillin (like ampicllin but higher serum levels) |
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semisynthetic penicillin - acid resistant - resistant to penicillinase - available oraly
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oxacillin
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like peniccilins but substitute a dihydrothiazine ring instead of the thiazolidine ring of the penicillins
cidal or static? |
cephalosporins - bacteriocidal
good for people with penicillin allergies |
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cephalosporins work against what kind of bacteria
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broad spectrum, gram + and some gm - bacilli
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first generation cephalosporin cefazolin is good against
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g+ cocci, some gm - bacilii but NOT P.aeruginosa
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secod generation of cephalosporins (cefuroxime) is good against
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g- enterics, less effective against gm +
NOT effective gainst P. aeruginosa |
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third generation cephalosporin called ceftriaxone are effective against
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P. aeruginosa -
better CNS penetration improved B-lactamase stability |
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clavulanic acid and sulbactam are
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B-lactamase inhibitors
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vancomycin targets
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only gram + organisms
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binds R D-Ala-D-Ala
inhibiting RNA synthesis |
vancomycin
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D-alanine analong which inhibits cell wall synthesis and is used to treat TB
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cycloserine
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Bacitracin (a cell wall inhibitor) treats what kind of bacteria
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Gm + organism
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restricted to topical (in neosporin)
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bacitracin
a cell wall inhibitor |
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an inhibitor of protein synthesis -bacteriocidal but not lytic.
binds 30 S? fights what kind of bacteria enters through imperfections in growing membrane |
streptomycin
gm - |
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streptomycin targets what kind of bacteria
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gram-negative
note: stretpomycin and gentamicin are aminoglycosides and there fore are inhibited by anaerobic and acid conditions |
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group of drugs that are
used for treatment of immunocompromised patients because limited to serious infections |
aminoglycosides
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blocks the binding of aminoacyl-RNA to 30S
bacteriostatic not to be give during pregnancy or kids (mottled anamel) |
tetracycline or doxycycline
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resistance to efflux pump
derivitive of tetracycline |
tigecycline
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blocks chain elongation
bacteriostatic inhibits 50S |
erythromycin
spectrum similar to penicillin but includes mycoplasma and chlamydia |
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like erythromycin but broader spectrum, high sustained tissue concentrations
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azithromycin
is a macrolide (binds 503) like erthromycin |
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blocks chain elongation
is aminoglycoside bacteriostatic (sometimes bacteriocidal) used against B.fragilis |
chloramphenicol
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a derivitive of lincomycin. has activity against Gm+ and moderate activity against anaerobes.
bacteriostatic inhibits peptidyl transfer aminoglycoside |
clindamycin
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two drugs that inhibit translation by interactions with ribosome and have potential for treating VREF, MRSA
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oxazolidinones and streptogramins
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binds tRNA synthetase inhibits translation
bacteriostatic treatment of MRSA |
Mupirocin
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topical treatment of impetigo caused by s.aureaus and s.pyogenes
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mupirocin
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inhibitors of DNA replication
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Quinilones
e.g Nalidixic Acid Fluroquinolones and Nitroamidazoles |
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group of drugs that inhibit DNA gyrase and are bacteriocidal
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quinolones
e.g nalidixic acid works against Gm- enterics and good for treating UTI Bacteriocidal not for pregant women or children due to growing bone |
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should not be prescribed for pregnant women or children because they damage growing bone
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quinolones
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an anaerobic drug which binds DNA and fragments it
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nitroimidazoles
(metronidazole) good for Bacteriodes species bactericidal action requires anaerobic conditions |
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broad spectrum
inhibits RNA synthesis by binding B subunit of bacterial RNA polymerase, inhibiting specific binding to DNA |
rifampin
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efficeintly secreted in saliva - so useful as prophylactic against infectious bacteria (N. menigitidis!)
used in combo with other drugs cause resistance develops rapidly |
rifampin
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ethambutol and pyrazinamide are used
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TB
etham - static pyrazin - cidal |
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using penicillin and tetracycline would not work why
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penicillin requires growth and tetracycline is static
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penicillin and aminoglycosides work well together because
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one damages the cell wall and one is taken up poorly by bacterium
e.g streptomycin (aminoglycoside) enters through growing membrane |
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aminoglycosides are inhibited by
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acid, and anaerobic conditions
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hydrolyzes the lactone ring of erythromycin
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erythromycin esterase
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antibiotic efflux from cell is an issue for what two antibiotics
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tetracycline and fluconazole (an antifungal - inhibitor of membrane synthesis)
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alteration of ribosomal targets occur frequently for
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erythromycin and streptomycin
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mode of bacterial resistance of vancomycin
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alteration of cell wall precursor targets
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methicillin resistance is via
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altered affinity PBPs
(Neisseria, HiB, P. aeruginosa) |
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altered dihydropteroate synthetase
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sulfonamide
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four classes of drugs which inhibit protein synthesis
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aminoglysides (streptomycin)
macrolides (erythromycin) tetracycline chloramphenicol |
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mechanisma of resistance is an interference with transport of drug into cell / efflux pumps
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tetracycline
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mechanism of resistance is detoxificaiton of drug by acetylation of hydroxyl
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chloramphenicol
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mechanism of resistance is enzymatic methylation o 23S ribosomal RNA
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erythromycin
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altered target enzyme (gyrase, RNAP) affects what two drugs
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ciprofloxacin (a fluoroquinolone) and rifampin
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inhibits ergosterol synthesis (anti-fungal)
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azoles
fluconazole |
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topical or oral fungal infections
"swish and swallow" |
nystatin
is not absorbed by GI tract which is good cause it would be toxic systemically nystatin works by increase membrane permeability -by binding sterols in the CM. |
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fungal drug that affects membrae permeability, is fungicidal
it is polyene compounds so it binds sterols in cell membrane |
amphotericin B
(is only injectable) |
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amphotericin B - cidal or static
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cidal
Nystatin is static |
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inhibits cell membrane synthesis in fungus - used to treat thrush
fungistatic |
azoles
fluconazole |
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inhibitors of glucan synthesis
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echniocandins (Caspofungin)
dont get confused with Azoles which inhibit ergosterol synthesis. glucan is in fungal wall and ergosterol is in the CM |
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antimetabolite anti-fungal drugs which works by replacing uracil with 5-fluroururicil in fungal RNA
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Flucytosine
therefore interferes with DNA synthesis and is cidal or static |
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therapeutic index
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dose toxic to host/ dose therapeutic
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how does toatl cell count and viable cell count differ with bacteriostatic and bactericidal
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1. bacteriostatic: no change in total count, decrease viable
2. decrease total and viable |
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Quinolones work against what kind of bacteria and are therefore used to treat what
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work against Gm- enterics - used to treat UTI
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quinolones - cidal or static
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cidal
inhibitors of DNA replication e.g nalidixic acid - used against Gm - enterics |
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treatment of anthrax
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Ciprofoloxacin - a fluorquinolones
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inhibits gyrase AND topoisomerase so theoretically resistance will not develop rapidly due ot multiple DNA targets
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fourth generaion fluroquinolones
moxifloxacan |
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activated under anaerobic conditions
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nitroimidazoles
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polymyxin B and polyumyxin E (colisin) are cidal or static
they affect cell how |
cidal
affect membrane permeability |
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Streptomycin is not used except for treating
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tb -
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