Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Medical Microbiology > Antibiotics > Flashcards

Antibiotics Flashcards

1
Q

Beta-lactam antibiotics (mechanism of action)

A

Mechanism of action:

  • Bind PBPs and thus inhibit peptidoglycan crosslinking
  • bactericidal except against Enterococcus spp)

Includes: penicillins, cephalosporins, carbapenems, monobactams

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Vancomycin (Mechanism of action)

A
  • Binds to D-Ala and interrupts chain for peptidoglycan synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Vancomycin (Mechanism of resistance)

A

Altered binding site, D-alanyl-D-alanine

Thickened cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Vancomycin (Pharmacokinetics)

A
  • Poor oral bioavailability
  • Give IV
  • Well distributed
  • Not extensively metabolized
  • Renal elimination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Vancomycin (Adverse effects)

A

Red Man’s syndrome

Nephrotoxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Beta-lactam antibiotics (mechanism of resistance)

A

Mechanisms of resistance:

  • Altered PBPs with decreased affinity for beta-lactam drug
  • Mechanism in gram+ (Staphylococcus, Enterococcus, Streptococcus)
    • Overexpression of efflux pumps, loss of porins, B-lactamases (catalyze hydrolysis of B-lactam ring; periplasmic space of gram-, outside cell wall in gram+)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Beta-lactams (Pharmacokinetics)

A

Pharmacokinetics:

  • Moderate absorption
  • Moderate distribution (some carbapenems good for CNS)
  • Not extensively metabolized
  • 80-100% excreted renally unchanged (except nafcillin, oxacillin, ceftriaxone)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Beta-lactams (Adverse effects)

A

Adverse effects:

  • Hypersensitivity (rash)
  • Seizures (at high doses; esp carbapenems)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Fosfomycin (mechanisms)

A

Mechanism of action:
- inhibits first step in peptidoglycan synthesis by binding to enzyme that catalyzes formation of N-acetylmuramic acid (precursor of peptidoglycan)

Mechanism of resistance:
- decreased drug uptake, target site modification, enzymatic inactivation

Pharmacokinetics:

  • Orally
  • Excellent distribution
  • Excreted unchanged

Notes:

  • well tolerated
  • use for uncomplicated UTIs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Inhibitors of protein synthesis

A

Mechanism of action:
- inhibition of ribosomal function results in impaired protein synthesis

Mechanism of resistance:
- Efflux pump overepxression, ribosomal mutation or modification

Includes: aminoglycosides, macrolides, tetrcyclines, linezolid, clindamycin, tigecycline

Can be 50S or 30S inhibitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Linezolid (mechanism)

A

Mechanism of action:
50S inhibitor that blocks initiation of protein translation

Pharmacokinetics:

  • Excellent absorption
  • Extensive, including CSF, distribution
  • Metabolized by oxidation
  • 30-40% excreted unchanged in urine

Toxicity:

  • MYELOSUPPRESSION
  • Serotonin syndrome (with other serotonergic agents)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Macrolides, clindamycin (mechanism)

A

Mechanism of action:
50S inhibitor that blocks translocation of peptidyl-rRNAs which elongate peptide chain

(MACROLIDES)
Pharmacokinetics:
- Moderate absorption
- Extensive distribution (minimal CSF)
- Extensively metabolized hepatically (clarithromycin)
- Unchanged drug eliminated via feces (azithromycin). Unchanged drug and metabolites via urine (clarithromycin)

Toxicity:

  • Erythromycin used for pro-kinetic GI effects
  • Clarithro/Azithro have fewer GI side effects
  • Torsades de pointes (ventricular tachycardia with clarithromycin + CYP3A4 hepatic enzymes)
----------------------------------------------------------
(CLINDAMYCIN)
Pharmacokinetics:
- Very good absorption
- Extensive (minimal CSF) distibution
- Extensively metabolized hepatically
- Elimination mostly via bile/feces

Toxicity:
- C. dificile colitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Tetracyclines, tigecycline (mechanism)

A

30S inhibitors that block access of tRNAs to ribosomes

(TETRACYCLINES)
Pharmacokinetics:
- Good oral absorption (90-100% bioavailable); chelation decreases
- Extensive distribution, poor CSF
- Minocycline extensively metabolized hepatically, > doxycycline > tigecycline
- Mino eliminated biliary; doxy by feces/20% unchanged in urine; tige: via bile

Toxicity:

  • GI, esophageal ulceration (take with fluid and remain upright)
  • Gray to brown discoloration of teeth in children
  • Photosensitivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Aminoglycosides (mechanism)

A

30S inhibitors that bind 16S rRNA component of ribosome leading to mistranslation

Pharmacokinetics:

  • Minimal absorption
  • Poor distribution (not CNS)
  • No hepatic metabolism
  • Exclusively filtered as unchanged drug
    • Need pharmacokinetic monitoring to maximize peaks and minimize toxicity

Adverse effects:

  • Nephrotoxicity (proximal tubular cell accumulation, reversible)
  • also ototoxicity

Includes:

  • Gentamycin
  • Tobramycin
  • Amikacin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Trimethoprim/Sulfamethoxazole (mechanism)

A

Inhibitor of DNA/RNA synthesis
Inhibit nuclear acid synthesis

Mechanism of resistance:
- Bypass targets; structural changes in target enzymes

Pharmacokinetics:

  • Excellent absorption
  • Extensive distribution, including CSF
  • SMX extensively metabolized hepatically; minimal hepatic metabolism for TMP
  • SMX 30% excreted unchanged in urine; 70-90% for TMP

Toxicity:

  • Skin reactions in 3-4% patients (mild, Stevens-Johnson, toxic epidermal necrolysis)
  • Renal - mild elevations of serum creatinine; acute interstitital nephritis
  • Hematological - neutropniea, thrombocytopenia (rare)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Rifamycins (mechanism)

A

Mechanism of action:
Inhibits DNA-dependent RNA polymerase (inhibits RNA synthesis)

Mechanism of resistance:
- target site mutation

Pharmacokinetics:

  • Very well absorbed orally
  • Extensively distributed including CSF
  • Extensively metabolized hepatically
  • Biliary elimination

Toxicity:

  • Orange-red discoloration of tears, sweat, urine
  • Gastrointestinal
  • Hepatotoxicity (elevation in bilirubin to fulminant hepatitis)
  • Many drug-drug interactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Fluoroquinolones ( mechanism)

A

Mechanism of action:
- inhibit topoisomerases which catalyze reactions vital for DNA replication, transcription, recombination and repair

Pharmacokinetics:

  • Excellent absorption
  • Extensive distribution, moderate CNS penetration
  • Metabolism differs among agents:
    • Levo: no hepatic metabolism
    • Cipro: 10-20% total elimination
    • Moxi: >60% dose hepatically metabolized
  • Renal clearance depends on degree of hepatic metabolism

Toxicity:

  • CNS
  • Tendinitis with rupture
  • C dificile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Fidaxomicin (mechanism)

A

Mechanism of action:
- inhibiting transcription of bacterial RNA polymerase

Macrocyclic antibiotic, only used for C. dif infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Nitrofurantoin (mechanism)

A

Mechanism:
- appears that parent compound is reduced to form DNA-damaging oxygen radicals

Mechanisms of resistance:
- Mutations resulting in inhibition of reductase activity

Pharmacokinetics:

  • only PO availability
  • Very low drug levels in tissues and serum
  • Minimal metabolism
  • Extensively eliminated via urine (high urine concentrations), short half-life
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Metronidazole (mechanism)

A

Mechanism:
- Pro-drug; anaerobic nitro-reduction to radical metabolites that bind to and perturb DNA function

Mechanism of resistance:
- Rare outside of intrinsically-resistant organisms

Pharmacokinetics:

  • Excellent absorption (100% BA)
  • Extensive distribution (including CSF)
  • Extensive metabolism
  • Minimal renal elimination of unchanged drug but metabolites eliminated renally

Toxicity:

  • GI: metallic taste
  • Peripheral neuropathy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Daptomycin (mechanism)

A

Mechanism of action:
- Inserts into CM in Ca++ dependent manner, resulting in membrane depolarization via efflux of potassium that is associated with disruption of DNA, RNA, protein synthesis and possibly death

Mechanism of resistance:
- Multiple; thickened cell wall and altered binding site

Pharmacokinetics:

  • only IV absorption
  • LImited distribution, minimal CSF penetration
  • LImited metabolism
  • 90% excreted via kidney

Toxicity:

  • Muscle pain/weakness (CPK elevations)
  • Rash
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Polymyxins (mechanism)

Colistin or Polymyxin B)

A

Mechanism of action:
- Inserts into membranes and interacts with phospholipids, acts as cationic detergent

Mechanism of resistance:
- possible altered binding site (modification of phospholipids)

Pharmacokinetics:

  • IV only
  • Limited with minimal CSF penetration
  • Unclear metabolism
  • Minimal renal elimination of unchanged drug

Toxicity:

  • dose-related, reversible nephrotoxicity
  • Neurotoxicity and paresthesias
23
Q

Natural Penicillins

  • Penicillin V (PO)
  • Penicillin G, benzathine (IM)
  • Pencillin G, procaine (IM)
  • Penicillin G, Na/K (IV)
A

Good for:
Streptoccocus, Enterococcus (E. faecalis)
Treponema pallidum
Mouth anaerobes

Not good for:
Staphylococci
S. pneumoniae
Gram -

Notes:

  • only cidal against Enterococcus with aminoglycoside
  • Hypersensitivity, seizures at high dosese
24
Q

Aminopenicillins

A

Amoxicillin and Ampicillin (IV/PO)

Good for:

  • Streptococcus, Enterococcus, PLUS Listeria monocytogenes
  • Treponema pallidum
  • Mouth anaerobes
  • PLUS E coli, Proteus mirabilis, H influenzae (resistance)
  • PLUS Lyme

Notes:
- Hypersensitivity, seizures at high dosese

25
Aminopenicillins PLUS B-lactamase inhibitors
Ampicillin + Sulbactam (IV) Amoxicillin + Clavulanate (PO) Good for: - Streptococcus, Enterococcus, Listeria monocytogenes - PLUS MSSA* - Treponema pallidum - Mouth anaerobes - PLUS E coli, Proteus mirabilis, H influenzae, Klebsiella - PLUS Lyme - PLUS Bacteroides fragilis* Notes: - Hypersensitivity, seizures at high dosese - Diarrhea
26
Penicillinase Resistant Penicillins
Nafcillin/Oxacillin (IV) Dicloxacillin (PO) Good for: - EXCELLENT MSSA - Streptococcus Bad for: - Enterococcus - gram - Notes: - hepatotoxicity (oxacillin) - Interstititial nephritis (nafcillin) - Unique due to HEPATIC ELIMINATION
27
Extended Spectrum Penicillin PLUS B-lactamase inhibitor
Ticarcillin + Clavulanate (IV) Piperacillin + Tazobactam (IV) Good for: - EXCELLENT MSSA - PLUS Enterococcus spp - Gram - broad spectrum: including PSEUDOMONAS - Excellent anaerobic activity (including Bacteroides f.) Notes: - used commonly in hospitals for empiric coverage - diarrhea common - P/T is more potent gram- agent
28
1st Generation Cephalosporins Cefazolin (IV) Cephalexin (PO) Cefadroxil (PO)
Good for: - EXCELLENT for MSSA, Streptococcus - Limited gram-; some against E. coli, Klebsiella - Oral anaerobes Not for: - Enterococcus Notes: - hypersensitivity - seizures at high doses - Cefadroxil has longer half-life than cephalexin - Not for sinusitis, otitis media and lower respiratory infections
29
2nd Generation Cephalosporins 2A - Cefuroxime (IV/PO) - Cefaclor (PO) - Cefprozil (PO)
Good for: - MSSA, Streptococci - Limited gram-; E coli, Klebsiella PLUS H. influenzae - Oral anaerobes Not for: - Enterococcus Notes: - Use for sinusitis, otitis media (but many hospital gram- are resistant)
30
2nd Generation Cephalosporins 2B | - Cefoxitin
Good for: - Streptoccocus - PLUS B. fragilis (moderate) Not for: - MSSA - Enterococcus Notes: - Intraabdominal and pelvic infections
31
3rd Generation Cephalosporins - Ceftriaxone (IV) - Ceftibuten (PO) - Cefdinir (PO) - Cefpodoxime (PO) - Cefotaxime (IV) - Cefixime (PO)
Good for: - MSSA (moderate) - EXCELLENT Streptococcus - Broad gram- activity (no pseudomonas) Not for: - Enterococcus Notes: - Ceftriaxone has biliary elimination - extended half-life and Q12-24hr dosing - Ceftriaxone/Cefotaxine: gold-standard for community-acquired meningitis, N. gonorrhea, neuro Lyme
32
3rd Generation Cephalosporin | - Ceftazidime (IV)
Good for: - Gram- PLUS PSEUDOMONAS - oral anaerobes Not for: - Poor MSSA, Streptococcus, Enterococcus (none)
33
3rd Generation Cephalosporins | - Ceftaroline (IV)
Good for: - MRSA* (only B-lactam) - EXCELLENT Streptococcus - Broad gram- (not pseudomonas) - oral anaerobes Not for: - Enterococcus - Pseudomonas Notes: - Ceftaroline = ceftriaxone + MRSA
34
4th Generation Cephalosporin | - Cefepime (IV)
Good for: - MSSA, Streptococcus - Broad gram-, PLUS Pseudomonas - Oral anaerobes Not for: - Enterococcus
35
Aztreonam (monobactam)
Good for: - gram- including Pseudomonas Not for: - Gram+ - Anaerobes Notes: - Safe for patients with severe allergic reactions to other beta-lactams
36
Carbapenems - Imipenem/Cilastatin (IV) - Meropenem - Doripenem
Good for: - Streptococcus, MSSA - Decent: E. faecalis - EXCELLENT gram- including Pseudomonas and other MDRs - Broad anaerobes including excellent B. fragilis Notes: - imipenem has higher incidence of seizures in patients with decreased renal function or history - Cilastatin inhibits renal tubule brush border enzyme that hydrolyzes imipenem (not B-lactamase inhibitor)
37
Carbapenems | - Ertapenem
Good for: - EXCELLENT gram- (NOT PSEUDOMONAS) - Anaerobes (excellent B. fragilis) Not for: - less active for Gram+ - no Enterococcus - Pseudomonas Notes: - Q24 hr dosing
38
Vancomycin (IV and PO)
Good for: - Very good strep and MRSA/MRSE, Enterococcus( static) - (first line empirical) - C. DIFICILE (PO) Not for: - no Gram- (including gram- anaerobes) - no VRE Notes: - Causes Red Man's syndrome at infusion site - Nephrotoxicity - Used exclusively for GRAM+ and C.dif diarrhea
39
Fosfomycin (PO)
Good for: - EXCELLENT against E. COLI and other gram- (not pseudomonas) - Staphylococcus, Enterococcus, Streptococcus Not for: - Pseudomonas Notes: - well-tolerated - used as single dose oral regimen for acute cystitis in female (good due to increasing E. coli resistance
40
Trimethoprim/Sulfamethoxazole (IV/PO)
Good for: - Staph. aureus, Staph. epi, most MRSA/MRSE (STAPHYLOCOCCUS) - Most gram- (stenotrophomonas maltophilia) - PCP - Nocardia, Toxoplasma gondii - Not for: - Strep, entero - B. fragilis, other anaerobes - Pseudomonas Notes: - Skin rash, elevations of serum creatinine (inhibits secretion), acute interstitial nephritis - Myelosuppression - Many uses: GI, urinary, skin, pneumocystis, toxoplasmosis, nocardiosis - monitor for increase in INR - dosing based on Trimethoprim
41
Rifampin (IV/PO)
Good for: - M. TUBERCULOSIS - prophylaxis N. meningitidis - Staph/Strep Not for: - monotherapy for Staph/Strep - no Enterococcus Notes: - Orange-red discoloration of tears, sweat, urine - Hepatotoxicity - has MANY drug-drug interactions; used in combination (energing resistance) - Used for: tuberculosis, staphylococcal endocarditis, infections of prosthetic materials
42
Fidaxomicin (PO)
Good for: - variable for Entero, Staph, Strep - Gram+ anaerobes (C. dificile) Not for - Gram- Notes: - Only use for C. dif infection
43
Quinolones - Ciprofloxacin (IV/PO) - Levofloxacin - Moxifloxacin
Good for: - Levo/moxi - EXCELLENT for S. pneumo - Strep (moderate) - Cipro/Levo - EXCELLENT gram- (PLUS Pseudomonas) - Moxi - moderate gram- (poor pseudomonas) - Moxi - increased anaerobe (including B. fragilis) - Atypicals: Chlamydia, Mycoplasma, Legionella Not for: - Staph (resistance) - Enterococcus - anarobes Notes: - CNS, tendinitis with rupture, C. dif diarrhea/colitis - Used for: UTI, prostatitis, respiratory tract, GI bone and joint infections, STDs
44
Aminoglycosides - Gentamycin (IV) - Tobramycin - Amikacin
Good for: - synergistic with cell-wall active against against Enterococcus (cidal) - Broad spectrum gram- (including Pseudomonas) - amikacin is best - Strep and Staph (moderate) Notes: - Nephrotoxicity (via proximal tubular cell accumulation) - Always with cell-wall active agents for staph/strep/entero endocarditis - Double coverage for severe gram- infections - Need pharmacokinetic monitoring
45
Macrolines - Azithromycin (IV/PO) - Clarithromycin (PO)
Good for: - ATYPICALS: Legionella, Chlamydia, Mycoplasma - Strep penumoniae, other strep, MSSA (not first line) - H influenzae, N. gonorrhea, M. catarrhalis - H. pylori - Anaerobes, not B. fragilis - Mycobacterium avium complex (MAC) Not for: - not first line for gram+ Notes: - Erythromycin: pro-kinetic GI effects - Torsades de pointes - clarithromycin (with CYP34A) - USE for: atypicals in community-acquired pneumonia - Otitis, Sinusitis, Pneumonia - Clarithromycin: more prone to drug-drug interactions
46
Tetracyclines - Tetracycline (PO) - Doxycycline (IV/PO) - Minocycline (PO)
Good for: - Strep penumoniae, STAPH (MRSA), Enterococcus - Minimal for Strep pyogenes - H influenzae, N gonorrhea, M. catarrhalis - Campylobacter - EXTENSIVE against anaerobes, atypicals, Rickettsia, Lyme Notes: - GI/esophageal ulceration - Gray/brown discoloration of teeth in children - Photosensitivity - LImited gram- activity; limited use; good for COPD exacerbations, upper respiratory tract infections
47
Tigecycline (IV)
Good for: - EXTENSIVE gram+ (MRSA, VRE) - EXTENSIVE gram- (but no pseudomonas) - EXTENSIVE anaerobes (including b. fragilis) Not for: - pseudomonas Notes: - Not for bacteria
48
Clindamycin (IV/PO)
Good for: - Staph aureus (MRSA), S. epi, Strep spp (but not first line) - Good anaerobes Not for: - Enterococcus - Gram - Notes: - Nausea/vomiting/diarrhea - C. DIF COLITIS (so rarely used in oral infections, skin and soft tissue infection for those with penicillin allergy) - combination therapy in ncrotizing frasciitis
49
Linezolid (IV/PO)
Good for: - EXTENSIVE Gram+ (MRSA, most VRE) Not for: - Gram - Notes: - Myelosuppression - Serotonin syndrome - Use for resistant gram+ infections with few options
50
Nitrofurantoin (PO)
Good for: - most gram+ (including VRE) - E. coli, Klebsiella, Enterobacter Not for: - Proteus, Pseudomonas (always resistant) Notes: - GI symptoms - Pulmonary - can cause cough and dyspnea to fibrosis - Only used for UTIs (NOT pyelonephritis)
51
Metronidazole (IV/PO)
Good for: - EXTENSIVE anaerobes (B. fragilis) - Trichomonas - Giardia - H. pylori - C. DIF Not for: - gram+ or gram- Notes: - GI, metallic taste, peripheral neuropathy - Drug of choice for initial C. dificile disease
52
Daptomycin (IV)
Good for: - EXTENSIVE gram+ (MSSA, MRSA, VRE) Not for: - gram- - anaerobes/other Notes: - muscle pain/weakness (CPK elevation) - NOT for pneumonia - Used for: gram+ bloodstream infections resistant to first line
53
Polymyxins: - Polymyxin B (IV) - Colistin (IV)
good for: - EXTENSIVE gram- (inc Pseudomonas) Not for: - Gram+, anaerobes, other Notes: - dose-related, reversible nephrotoxicity - neurotoxicity and paresthesias - Last resort for MDR gram- infections (used in combination)

Medical Microbiology (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions