Abx * Flashcards

1
Q

Streptomycin

A

Aminoglycoside

  • Binds 30S ribosomal subunit, blocks 3 steps (initiation, translocation, mistranslation)
  • Rapidly bacteriocidal v. G-, post antibiotic effect
  • 2nd-line therapeutic treatment for TB in combo with another agent (INH)
  • Nephrotoxcicity (reversible), Ototoxicity (nonreversible), associated with >5 days of therapy
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2
Q

Tobramycin

A

Aminoglycoside

  • Binds 30S ribosomal subunit, blocks 3 steps (initiation, translocation, mistranslation)
  • Rapidly bacteriocidal v. G-, post antibiotic effect

Treatment of serious systemic G- infections, used in combination with B-lactam (synergism)

  • Nephrotoxcicity (reversible), Ototoxicity (nonreversible), associated with >5 days of therapy
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3
Q

Gentamycin

A

Aminoglycoside

  • Binds 30S ribosomal subunit, blocks 3 steps (initiation, translocation, mistranslation)
  • Rapidly bacteriocidal v. G-, post antibiotic effect

Treatment of serious systemic G- infections, used in combination with B-lactam (synergism)

  • Nephrotoxcicity (reversible), Ototoxicity (nonreversible), associated with >5 days of therapy
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4
Q

Amikacin

A

Aminoglycoside

  • Binds 30S ribosomal subunit, blocks 3 steps (initiation, translocation, mistranslation).
  • Rapidly bacteriocidal v. G-, post antibiotic effect

Treatment in cases of resistance to tobramycin and gentamycin caused by inactivating enzymes

  • Nephrotoxcicity (reversible), Ototoxicity (nonreversible), associated with >5 days of therapy
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5
Q

Neomycin

A

Aminoglycoside

  • Binds 30S ribosomal subunit, blocks 3 steps (initiation, translocation, mistranslation)
  • Rapidly bacteriocidal v. G-, post antibiotic effect

Limited to topical use (skin and eyes)

  • Nephrotoxcicity (reversible), Ototoxicity (nonreversible), associated with >5 days of therapy
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6
Q

Kanamycin

A

Aminoglycoside

  • Binds 30S ribosomal subunit, blocks 3 steps (initiation, translocation, mistranslation)
  • Rapidly bacteriocidal v. G-, post antibiotic effect

Limited to topical use (skin and eyes)

  • Nephrotoxcicity (reversible), Ototoxicity (nonreversible), associated with >5 days of therapy
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7
Q

Tetracycline

A

Tetracyclines

  • Bind 50S ribosomal subunit and interfere with protein synthesis by blocking ribosomal translocation
  • Generally bacteriostatic v. aerobic Gram+ and some Gram-

Indications:

  • Rikettsia (RMSF, typhus, Q)
  • STI’s (Chlamydia, etc)
  • Respiratory infections
  • skin and soft tissue infections (staph, acne)

Contraindications:
GI disturbnces, Teeth and bone issues. Not for children or pregnant women

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8
Q

Oxytetracycline

A

Tetracyclines

  • Bind 50S ribosomal subunit and interfere with protein synthesis by blocking ribosomal translocation
  • Generally bacteriostatic v. aerobic Gram+ and some Gram-

Indications:

  • Rikettsia (RMSF, typhus, Q)
  • STI’s (Chlamydia, etc)
  • Respiratory infections
  • skin and soft tissue infections (staph, acne)

Contraindications:
GI disturbnces, Teeth and bone issues. Not for children or pregnant women

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9
Q

Demeclocycline

A

Tetracyclines

  • Bind 50S ribosomal subunit and interfere with protein synthesis by blocking ribosomal translocation
  • Generally bacteriostatic v. aerobic Gram+ and some Gram-

Indications:

  • Rikettsia (RMSF, typhus, Q)
  • STI’s (Chlamydia, etc)
  • Respiratory infections
  • skin and soft tissue infections (staph, acne)

Contraindications:
GI disturbnces, Teeth and bone issues. Not for children or pregnant women

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10
Q

Minocycline

A

Tetracyclines

  • Bind 50S ribosomal subunit and interfere with protein synthesis by blocking ribosomal translocation
  • Generally bacteriostatic v. aerobic Gram+ and some Gram-

Indications:

  • Rikettsia (RMSF, typhus, Q)
  • STI’s (Chlamydia, etc)
  • Respiratory infections (community-acquired pneumonia)
  • skin and soft tissue infections (staph, acne)

Contraindications:
GI disturbnces, Teeth and bone issues. Not for children or pregnant women

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11
Q

Doxycycline

A

Tetracyclines

  • Bind 50S ribosomal subunit and interfere with protein synthesis by blocking ribosomal translocation
  • Generally bacteriostatic v. aerobic Gram+ and some Gram-

Indications:
MDR Bacteria - intra-abdominal, skin, soft-tissue infections, community acquired pneumonia

Contraindications:
GI disturbnces, Teeth and bone issues. Not for children or pregnant women

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12
Q

Tigeclycine (glycylcycline)

A

Tetracyclines

  • Bind 50S ribosomal subunit and interfere with protein synthesis by blocking ribosomal translocation
  • Generally bacteriostatic v. aerobic Gram+ and some Gram-

Indications:
Antrhax, malaria, lyme disease

Contraindications:
GI disturbnces, Teeth and bone issues. Not for children or pregnant women

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13
Q

Erythromycin

A

Macrolide

  • Bind 50s ribosomal subunit, interfere with protein synthesis by block ribosomal translocation step
  • Generally bacteriostatic v. aerobic G+ and some G- bacteria

Respiratory infections, Acute otitis media, Streptococcal pharyngitis, Chlamydial infections, Diphtheria, Pertussis

Contraindications: GI disturbances and hepatotoxicity

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14
Q

Clarithromycin

A

Macrolide

  • Bind 50s ribosomal subunit, interfere with protein synthesis by block ribosomal translocation step
  • Generally bacteriostatic v. aerobic G+ and some G- bacteria

Respiratory infections, Acute otitis media, Streptococcal pharyngitis, Chlamydial infections, Diphtheria, Pertussis

Contraindications: GI disturbances and hepatotoxicity

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15
Q

Azithromycin

A

Macrolide

  • Bind 50s ribosomal subunit, interfere with protein synthesis by block ribosomal translocation step
  • Generally bacteriostatic v. aerobic G+ and some G- bacteria

Respiratory infections, Acute otitis media, Streptococcal pharyngitis, Chlamydial infections, Diphtheria, Pertussis

Contraindications: GI disturbances and hepatotoxicity

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16
Q

Telithromycin

A

Macrolide

  • Bind 50s ribosomal subunit, interfere with protein synthesis by block ribosomal translocation step
  • Generally bacteriostatic v. aerobic G+ and some G- bacteria

HEPATOTOXICITY –> ONLY APPROVED FOR COMMUNITY-ACQUIRED PNEUMONIA

Contraindications: GI disturbances and hepatotoxicity

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17
Q

Clindamycin

A

Lincosamide

  • Binds 50S Ribosomal subunit and interferes with protein synthesis by blocking ribosomal translocation step.
  • Bacteriostatic v. aerobic and anaerobic G+

Skin and soft-tissue infections

Contraindications: Diarrhea, pseudomembranous colitis caused by C. diff, skin rashes

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18
Q

Quinupristin/Dalfopristin

A

Streptogramins

  • Bind 50S ribosomal subunit, interfere with protein synth by blocking ribosomal translocation and inhibiting peptide elongation
  • Active v. most G+ bacteria, combination is bacteriocidal v. streptococci, most staph, bacteriostatic vs. enterococci.

Indications:
- treatment of infections caused by VRE, treatment of MSSA

Contraindications: Infusion-related effects of IV only combination, Arthralgias, myalgias

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19
Q

Linezolid

A

Oxazolidinone

  • Binds 50S ribosomal subunit, interferes with protein synthesis by blocking initiation.
  • active against aeorobic and anaerobic G+ bacteria.
  • Bactericidal v. streptococci, bacteriostatic v. staph and enterococci

Indications: treat MDR G+ bacteria MRSA, VRE, penicillin-resistant streptococci.

Side effects: myelosuppression (leukopenia, pancytopenia, thrombocytopenia) with treatment >2 weeks

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20
Q

Sulfisoxazole

A

Anti-folate sulfonamide

  • Competitive antagonist of dihydropteroate synthase
  • bacteriostatic v. many G- and some G+ bacteria

UTI (in combo)

Side Effects: Allergic reactions (fever, rash, photosensitivity, GI), crystalluria, hematuria

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21
Q

Sulfamethoxazole (SMX)

A

Anti-folate sulfonamide

  • Competitive antagonist of dihydropteroate synthase
  • bacteriostatic v. many G- and some G+ bacteria

UTI (in combo)

Side Effects: Allergic reactions (fever, rash, photosensitivity, GI), crystalluria, hematuria

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22
Q

Sulfasalazine

A

Anti-folate sulfonamide

  • Competitive antagonist of dihydropteroate synthase
  • bacteriostatic v. many G- and some G+ bacteria

Ulcerative colitis and enteritis

Side Effects: Allergic reactions (fever, rash, photosensitivity, GI), crystalluria, hematuria

23
Q

Trimethoprim/Sulfamethoxazole (TMP-SMX)

A

Anti-folate TMP-SMX Combo

  • TMP is a competitive antagonist of dihydrofolate reductase.
  • TMP is bacteriostatic v. many G- and some G+
  • SMX Competitive antagonist of dihydropteroate synthase
  • SMX bacteriostatic v. many G- and some G+ bacteria

TMP-SMX is bacteriocidal

Indications: UTI, PCP, Shigellosis, Salmonella, prostatitis, acute exacerbations of chronic bronchitis.

Contraindications: 5 days of treatment, megaloblastic anemia, leukopenia

24
Q

Ciprofloxacin

A

Fluoroquinolones

  • Inhibit TOPO II (DNA gyrase) in G- and inhibit TOPO IV in G+
  • Bactericidal v. G-, G+

Indications:

  • UTI
  • Diarrhea from shigella, salmonella, E. coli
  • soft tissue bone and joint infections
  • intra-abominal infections
  • *anthrax treatment and prevention

Contraindications: generally well tolerated, minor GI disturbances

25
Q

Lomefloxacin

A

Fluoroquinolones

  • Inhibit TOPO II (DNA gyrase) in G- and inhibit TOPO IV in G+
  • Bactericidal v. G-, G+

Indications:

  • UTI
  • Diarrhea from shigella, salmonella, E. coli
  • soft tissue bone and joint infections
  • intra-abominal infections

Contraindications: generally well tolerated, minor GI disturbances

26
Q

Levoflaxin

A

Fluoroquinolones

  • Inhibit TOPO II (DNA gyrase) in G- and inhibit TOPO IV in G+
  • Bactericidal v. G-, G+

Indications:

  • UTI
  • Diarrhea from shigella, salmonella, E. coli
  • soft tissue bone and joint infections
  • intra-abominal infections
  • **Respiratory tract infections

Contraindications: generally well tolerated, minor GI disturbances

27
Q

Ofloxacin

A

Fluoroquinolones

  • Inhibit TOPO II (DNA gyrase) in G- and inhibit TOPO IV in G+
  • Bactericidal v. G-, G+

Indications:

  • UTI
  • Diarrhea from shigella, salmonella, E. coli
  • soft tissue bone and joint infections
  • intra-abominal infections

Contraindications: generally well tolerated, minor GI disturbances

28
Q

Gemifloxacin

A

Fluoroquinolones

  • Inhibit TOPO II (DNA gyrase) in G- and inhibit TOPO IV in G+
  • Bactericidal v. G-, G+

Indications:

  • UTI
  • Diarrhea from shigella, salmonella, E. coli
  • soft tissue bone and joint infections
  • intra-abominal infections
  • ** Resipiratory tract infections

Contraindications: generally well tolerated, minor GI disturbances

29
Q

Moxifloxacin

A

Fluoroquinolones

  • Inhibit TOPO II (DNA gyrase) in G- and inhibit TOPO IV in G+
  • Bactericidal v. G-, G+

Indications:

  • UTI
  • Diarrhea from shigella, salmonella, E. coli
  • soft tissue bone and joint infections
  • intra-abominal infections
  • ** Resipiratory tract infections

Contraindications: generally well tolerated, minor GI disturbances

30
Q

Penicillins

A

penicillin G, cloxacillin, amoxicillin
mimic D-ala-D-ala, blocking peptidoglycan x-link, no more petidoglycan additions to cell wall.

  • acid labile, B-lactamase susceptible.
  • vs. g+, g- cocci, non-B-lactamase-producing anaerobes
31
Q

Clavulinic acid

A

beta-lactamase inhibitor, must be Rx with a beta lactam like penicillan. (sulfbactam and tazobactam are other beta-lactamase inhibitors)

32
Q

cefazolin

A

1st generation cephalosporin

  • Broad spectrum, best v. G+
  • Used for surgical prophylaxis, does not penetrate CNS
33
Q

cefamandole

A

2nd generation cephalosporin

  • G+, G-
  • no allergic cross-reactivity with penicillin
34
Q

ceftazidime

A

3rd generation cephalosporin

  • more G-, less G+
  • some cross to CNS
  • vs. inducible B-lactamase production but not constitutive B-lactimase producing strains
35
Q

cefeprime

A

4th generation cephalosporin

  • True broad spectrum drugs
  • penetrate CNS
  • more reisistant to chromosomal B-lactamases
  • Good against pseudomonas, enterobacteriacae, staph, haemophilus, tessera, most penicillin resistant strep.
36
Q

ceftaroline

A

latest generation cephalosporin

  • approved against MRSA
  • high affinity toward MRSA transpepsidase
  • administered IV
  • works on G+, G-
37
Q

aztreonam

A

monobactam

  • no activity toward G+ ( does not bind transpeptidase)
  • vs. G- rods, resistant to B-actamases
38
Q

carbapenem

A

imipenem

  • broad spectrum against g- rods g+ and anaerobes (mixed infections)
  • Inactivated by dehydropeptidases in renal tubules so use CILASTATIN to increase t1/2
39
Q

polymyxins

A

lipopetides (membrane disruptors)

  • large, used topically in neosporin
  • perforates G- bacteria by binding lipoplysacc. on membrane
  • resistance = lipopolysaccharide structural changes
40
Q

Inhibitors of peptidoglycan precursors

A

fosfomycin, bacitracin, D-cycloserine

41
Q

Oxacillin, cloxacillan, and dicloxacillin

A

Anti-staphylococcal penicillans

  • acid stable, B-lactamase resistant
  • vs. B-lactamase-producing staph, penicillan-susceptible strep and pneumonococci.
  • NOT for enterococci, anaerobic bacteria, G- occci and rods.
42
Q

amoxicillan

A

extended-spectrum penicillans

  • acid stable
    vs. G- because they penetrate outer membrane
  • B-lactamase susceptible.
  • Use in UTIs, otitis, LRT infections
43
Q

meropenam

A

carbapenam, resistant to modification by renal dehydropeptidase

44
Q

Vancomycin

A

Non-beta-lactam cell wall synthesis inhibitor

  • glycopeptide
  • large complicated structure binds D-ala-D-ala in cell wall
  • vs. G-
  • VRE = D-Ala-D-Lac, reduce binding affinity of Vanco
  • Vanco-resistant Staph creates thickened peptidoglycan layer
45
Q

Daptomycin

A

lipopeptide pore former

  • makes membrane pores__> K+ exists without cell rupture. Bacteria cannot grow.
  • v. G+ skin and soft tissue infections involving MRSA
46
Q

Peptidoglycan precursors assembly steps

A
  1. Nag converted to Nam-UDP (Fosfomycin)
  2. Peptide chains added to Nam-UDP (ala, glu, lys)
  3. More peptide chains added to Nam-UDP (D-ala, D-ala)
  4. 1 Lipid phosphotase dephosphorylates a lipid carrier on cell membrane (Bacitracin)
  5. Nam-UDP added to lipid on lipid membrane with NAG
  6. Flipped to outside
47
Q

Fosfomycin

A

Cell membrane synthesis inhibitor
Inhibits first committed step in cell wall-synthesis; Nag conversion to Nam by MurA
- TB naturally resistant

48
Q

Bacitracin

A

Cell membrane synthesis inhibitor
Inhibits lipid phosphotase that dephosphorylates the lipid carrier of Nam and Nag.
- use topically, nephrotoxic
- vs. G+, used with other Abx

49
Q

D-cycloserine

A

Cell membrane synthesis inhibitor
- competitively inhibits alanine racemes and D-ala ligase
when d-ALA to be addd to Nam. Looks like D-alanine.
- serious toxicity (Dose related CNS: tremors, convulsions, psychosis)
- 2nd line for TB

50
Q

Isoniazid (INH)

A
  • bactericidal against extracellular and intramacrophage mycobacteria
  • target mycolic acid synthesis in mycobacterial membrane
  • Use with other drugs
  • TB
  • activated by bacterial KatG, compound with NAD
  • targets FAS-II multiple enzyme system which makes long chain on mycolic acid
  • hepatitis, peripheral neuropathy (looks like B6)
  • metabolism depends on fast or slow acetylators (determined by genetics)
51
Q

Ethambutol (EMB)

A
  • Bacteriostatic mycobacterial drug
  • Targets arabinogalactan in mycobacterial membrane
  • blocks EmbA and EmbB arabinosyl transferases, weaken cell wall, make TB susceptible to damage
  • works bets against fast growing extracellular Mtb
  • can cause red-green color blindness, optic neuritis
52
Q

Pyrazinamide (PZA)

A

TB/mycobacterial drug that inhibits protein synthesis by targeting ribosomal protein S1 in latent bacteria.
- a stalled ribosome presents danger to cell (incomplete polypeptide) and cell uses RpsA/tmRNA mechanism to recycle the ribosome. PZA interacts with RpsA, to block the ribosome from interacting with tmRNA. Trans-translation is blocked.
Stalled ribosome => depletion of available ribosomes, accumulation of deleterious proteins.

53
Q

Rifampin (RIF)

A

First line TB drug

  • RNA synthesis inhibitor, inhibits transcription elongation (bacterial nascent RNA gets stuck, cannot depart from gene promotors)
  • bacteriacidal to G-, G+, mycobacteria, chlamydia
  • complex, semi-synthetic
  • induces P450 CYP3A (increased elimination of other drugs)
54
Q

Rifabutin and Rifapentine

A

Act like Rifampin but they are more potent, longer t1/2, better membrane permeability, and less CYP3A induction