Microbiology Antibiotics 2 Flashcards
(74 cards)
1
Q
Fluoroquinolones example
A
- Ciprofloxacin
- Levofloxacin
- Moxifloxacin
2
Q
Aminoglycosides example
A
• Gentamicin
3
Q
Glycopeptides example
A
- Vancomycin
* teicoplanin
4
Q
Macrolides example
A
- Erythromycin
* Clarithromycin
5
Q
Tetracyclines example
A
• Minocycline
6
Q
Fluoroquinolones: Used
A
Mainly used in hospital to treat Gram negative infection and lower resp tract infections
7
Q
Fluoroquinolones: Action
A
By inhibiting DNA gyrase,
8
Q
Fluoroquinolones: Resistance
A
Increasingly common – mainly target site modification but also efflux pumps.
9
Q
Fluoroquinolones:Absorption
A
Good oral bioavailability so po often as good as iv
10
Q
Fluoroquinolones:Distribution
A
Wide tissue distribution (2-3 L/Kg)
11
Q
Fluoroquinolones:Excretion and metabolism
A
Excretion y metabolism (ciprofloxacin, moxifloxacin) Renal clearance (Ciprofloxacin, moxifloxacin, levofloxacin)
12
Q
Fluoroquinolones: Side effects
A
Generally safe: • Rashes/phototoxicity • Tendenitis and rupture • GI upset • OTC prolongation (moxifloxacin) - (more likely to have ventricular tachy arrhythmia) • Hepatotoxicity
13
Q
Spectrum-ciprofloxacin: targets
A
- Aerobic Gram negative bacterial (coliforms, Pseudomonas, gonococci, H. influenza, atypical chest pathogens (legionella,mycoplasma, chlamydia))
- Border line activity against S.aureus and streptococci
- Not active against anaerobes
- Some activity against M. tuberculosis
14
Q
Spectrum – moxifloxacin: Target
A
- Much improved activity versus Staphylococci and Streptococci
- Poor activity vs. P.aeruginosa, better activity against anaerobes
15
Q
Spectrum – moxifloxacin:Indications
A
- Community acquired chest infections (moxifloxacin/levofloxacin)
- UTI/acute pyeonephitis (ciprofloxacin, levofloxacin) NB resistanct
- Intraabdominal infection (+ metronidazole)
- Bone/joint infection
- Oral therapy of P.aeruginosa (ciprofloxacin)
16
Q
Aminoglycosides: Action
A
Inhibiting of protein synthesis at ribosoms
17
Q
Aminoglycosides: Resistance by
A
Enzymes (aminoglycoside monitoring enzymes) but rare
18
Q
Aminoglycosides: Absorption
A
Intravenous/Im only
Poor oral absorption
19
Q
Aminoglycosides: Distribution
A
Modest tissue penetration – concentrated in the kidney and ears (toxicity)
20
Q
Aminoglycosides:Excretion
A
Renal excretion – accumulation in renal failure, no metabolism
21
Q
Aminoglycosides:Examples
A
Gentamicin
Tobramycin
Amikacin IV
22
Q
Aminoglycosides: Reduced use because
A
Toxicity requires therapeutic drug monitoring
23
Q
Aminoglycosides: Antimicrobial spectrum
A
Broad Gram negative activity
Coliform
P.aeruginosa
No anaerobic activity
24
Q
Aminoglycosides: Indications
A
- In combination therapy for intra abdominal infection
- In combination therapy for infective endocarditis
- In combination therapy for neutropaenic sepsis
- In combination therapy for neonatal sepsis (pen/fluclox)
- In combination therapy for P. aeruginosa infection (Cf)
- In combination therapy for S. aureus
25
Aminoglycosides: Side effects
7. Nephrotosicity (reversible)
| 8. Otototoxicity (irreversible)
26
Glycopeptides Example
Vancomycin
27
Glycopeptides Absorption
Intravenous hospital only, wide use to treat multi resistant Gram positive infection, especially MRSA
28
Glycopeptides Action
Inhibiting cross linking of bacterial cell wall
29
Glycopeptides Resistance
Rare except in Enterococci and due to altered target side (enterococci, Staphylococci) and permeability (Staphylococci)
30
Glycopeptides Excretion
Renal
31
Glycopeptides Metabolism
None
32
Glycopeptides Absorption note
Used for C.diff as although it has no oral bioavailabiity this doesn’t matter as it can target the gut without being absorbed.
33
Glycopeptides Side effects
Nephrotoxicity (around 10%) increased by use of other
Nephrotoxicity agents (gentamicin, frusemide)
Otoxicity very rare
Red man syndrome 9vancomycin) – histamine release mean the does is given too quickly
Thrombocytopenia (teicoplanin in big doses)
34
Glycopeptides Requires
Therapeutic drug monitoring
35
Glycopeptides Spectrum
Broad Spectrum: Active against nearly all gram positive bacteria, expecially multi resistant strains.
Not activie against Gram negative bacteria
36
Glycopeptides Indications
* MRSA infection
* Clostridium difficle associated diarrhoea (CDAD) as 2st line treatment
* Multiresistant Gram positive infection i.e. coagulase negative Staphylococci, Cornebacteria, Enterococci
* Prosthetic infection (Line, joint tc
* Penicillin allergy
37
Macrolides: Examples
Erythromycin/clarithromycin
38
Macrolides: Absorption
* IV and po agents widely used in hospital and community to treat lower respiratory tract infection and in penicillin allergy.
* Reasonable bioavailability
* Good oral absorption
39
Macrolides: Action
Inhibition of protein synthesis at ribosome
40
Macrolides: Resistance
Common, due to target modification
41
Macrolides: Distribution
Good tissue penetration
42
Macrolides: Excretion
Biliary and renal
43
Macrolides: Side effects
Nausea and GI upset, especially erythromycin (pharmacological effect on stomach motility)
44
Macrolides: Spectrum
1. Active against gram positive organism i.e. s. aureus ( not MRSA), Streptococci, resistance 10-20%
2. Active against atypical respiratory pathogens legionella, Mycoplasma, chlamydia
3. No activity against Gram negatives except for campylobacter
45
Macrolides: Indications
* Skin/soft tissue infection if penicillin allergic
* Community acquired pneumonia
* Campylobacter infection
* H. Pylori
* (Staph and strep)
46
Tetracycines: Examples
Minocycline
| Doxycycline
47
Tetracycines: Used in
Primary Care to treata acne
| In hospital as oral therapy for MRSA
48
Tetracycines: Action
Inhibits synthesis at ribosome
49
Tetracycines: Resistance
Relatively common due to efflux pumps and target site modification
50
Tetracycines: Contraindicated in children as
Concentrated in bones/teeth, bind to calcium
51
Tetracycines: Absorption
Only orally
52
Metronidazole: Absorption
Good bioavailability
| Available as iv/po
53
Metronidazole: Widely used to
Treat anaerobic infection
54
Metronidazole: Action
Disrupts DNA
55
Metronidazole: Distribution
Wide tissue distribution
56
Metronidazole: Resistance
Very rare in anaerobes
57
Metronidazole: Safety concerns
Early pregnancy
| Disulphuram-like reaction with alcohol, rare peripheral neuropathy on long therapy (Augments hangover)
58
Trimethoprim: Absorption
Po/Iv only with sulphamethoxazole (co-trimoxazole) to treat PCP
59
Trimethoprim: Used to treat
Uncomplicated UTI
60
Trimethoprim: Action
Inhibits Folate metabolism by inhibition of dihydrofolate reductase
61
Trimethoprim: Resistance
By over production or modification target enzyme enzyme (20% E.coli)
Renal excretion
62
Linezolid Which forms is available for clinical use
Oxazolidinase
63
Linezolid Active against
A wide range of gram positive bacteria including multi-resistant strains (MRSA, VRE)
64
Linezolid Absorption
Good bioavailability
65
Linezolid Penetration
Moderate/good tissue distribution
66
Linezolid Excretion/metabolism
None enzymatic degradation
| Breakdown products renally excreted
67
Daptomycin: Absorption
Only lipopeptide antibiotic available. Iv only.
68
Daptomycin: Active against
A wide range of gram positive bacteria including multi resistant strains (MRSA, VRE)
69
Daptomycin: Absorption
Poor oral absorption
| IV only
70
Daptomycin: Exrection
Renal
71
Daptomycin: Penetration
Poor lung penetration
72
Daptomycin: Toxicity
Muscle toxicity
73
Daptomycin: Second line for
Gram positive infection
74
Daptomycin: Not suitable for
Use in lung infection
