Antibiotics 1 Flashcards
1
Q
Describe the characteristic structures of gram-positive bacterium [2]
A
- thin cell membrane
- thick peptidoglycan cell wall
2
Q
Describe the characteristics structures of gram-negative bacterium [4]
A
- thin cell membrane
- thin peptidoglycan cell wall
- thick periplasm
- outer membrane
3
Q
What is a periplasm? [1]
A
concentrated gel-like matrix in the space between the inner cytoplasmic membrane and the outer membrane of the bacteria
4
Q
What do antibiotics tend to target on a bacterium? [4]
A
- cell wall peptidoglycan
- metabolism
- DNA
- ribosome
5
Q
What are the 2 types of antibiotics (classifed in terms of action)? [2]
A
- bactericidial antibiotics
- bacteriostatic antibiotics
6
Q
How do bactericidal antibiotics work? [2]
A
- Achieve sterilisation of the infected site by directly killing bacteria
- Lysis of bacteria can lead to release of toxins and inflammatory material
7
Q
How do bacteriostatic antibiotics work? [2]
A
- Suppresses growth but does not directly sterilise infected site
- Requires additional factors to clear bacteria → immune mediated killing
8
Q
Define the term: antibiotic spectrum [1]
A
The range of bacterial species effectively treated by the antibiotic
9
Q
What are the features of broad spectrum antibiotics? [2]
- hints:
- definition?
- function?
A
- Antibiotics that are active against a wide range of bacteria
- Treat most causes of infection but also have a substantial effect on colonising bacteria
10
Q
What are the features of narrow spectrum antibiotics? [3]
- hint:
- definition?
- when is it useful?
- limitations?
A
- Antibiotics that are active against a limited range of bacteria
- Useful only where the cause of the infection is well defined
- Have a much more limited effect on colonising bacteria
11
Q
Give examples of gram negative bacteria [5]
A
- pseudomonas
- haemophilus
- neisseria
- other coliforms
- E. coli
12
Q
Give examples of gram positive bacteria [3]
A
- staphylococcus
- enterococcus
- streptococcus
13
Q
Give examples of anaerobes [2]
A
- clostridium
- bacteroides
14
Q
What are the 3 types of antibiotic therapies? [3]
A
- guided therapy
- empirical therapy
- prophylactic therapy
15
Q
What is guided therapy? [1]
- hint: what is it dependent on?
A
Depends on identifying cause of infection and selecting agent based on sensitivity testing
16
Q
What is empirical therapy? [2]
- hint:
- definition?
- when is it used?
A
- Best (educated) guess therapy based on clinical/epidemiological acumen
- Used when therapy cannot wait for culture
17
Q
What is prophylactic therapy? [1]
A
preventing infection before it begins
18
Q
What are the types of antibiotic associated harm? [2]
A
- disruption of bacterial flora
- development of C. difficile colitis
19
Q
Overgrowth of bacterial flora with yeasts can lead to…? [1]
A
thrush
20
Q
Overgrowth of bacterial flora of the bowel can lead to…? [1]
A
diarrhoea
21
Q
What type of antibiotic is used for guided therapy? Narrow spectrum or broad spectrum? [1]
A
narrow spectrum antibiotic
22
Q
What type of antibiotic is used for empirical therapy? Narrow spectrum or broad spectrum antibiotics? [1]
A
broad spectrum antibiotic
23
Q
What are the 5 types of β-lactam antibiotics? [5]
A
- Penicillin
- Cephalosporins
- Carbapenems
- Monobactams
- β-lactam/β-lactamase inhibitor combinations
24
Q
Give 3 examples of penicillin (β-lactam antibiotics) [3]
A
- Benzylpenicillin
- Flucloxacillin
- Amoxicillin
25
Give an example of cephalosporins (β-lactam antibiotics) [1]
Ceftriaxone
26
Give an example of carbapenems (β-lactam antibiotics) [1]
meropenem
27
Give an example of monobactams (β-lactam antibiotics) [1]
aztreonam
28
Give 2 examples β-lactam/β-lactamase inhibitor combinations [2]
1. co-amoxiclav
2. piperacillin/tazobactam
29
Describe the mechanism of action of ß-lactam antibiotics [4]
all ß-lactams share the same branching structure of peptidoglycan which acts to inhibit crosslinking of cell wall peptidoglycan leading to lysis of bacteria
* it is bacteriostatic
30
Define beta-lactamases [1]
enzymes that lyse and inactivate beta-lactam drugs
31
Which organisms commonly secrete beta-lactamases? [2]
1. gram -ve bacteria
2. S. aureus
32
What is the complication beta-lactamase secretion? [1]
high level resistance to antibiotic (usually total antibiotic failure)
33
How are ß-lactam antibiotics typically administered? [2]
1. most are given intravenously (IV)
2. some can be given orally
* amoxicillin
* flucloxacillin
* **however vomiting limits dose**
34
How are ß-lactam antibiotics usually excreted? [2]
* Usually excreted unchanged in urine
* Some also via bile
35
What is the half-life of the β-lactam: benzylpenicillin? [1]
1 hour
36
What is the half-life of the β-lactam: ceftriaxone? [1]
8 hours
37
What are the potential GI toxicity adverse effects of β-lactam antibiotics? [3]
1. nausea/vomiting
2. diarrhoea
3. cholestasis
38
What are the potential hypersensitivity adverse effects of β-lactam antibiotics? [3]
1. type 1 hypersensitivity
* urticaria
* anaphaylaxis
2. type 4 hypersensitivity
* mild to severe dermatology
3. interstitial nephritis
39
What are the potential infection adverse effects of β-lactam antibiotics? [2]
1. candidiasis (oral/vulvovaginal)
2. *clostridium difficle* infection
40
What are the miscellaneous rare adverse effects of β-lactam antibiotics? [3]
1. seizure
2. haemolysis
3. leukopaenia
41
What is a urticarial rash? [1]
raised, itchy rash that appears on the skin in type 1 hypersensitivity
42
How is benzylpenicillin typically administered? [1]
via IV
43
What type of agent is benzylpenicillin?
Narrow spectrum or broad spectrum? [1]
narrow spectrum antibiotic
44
Which bacteria are **benzylpenicillin** effective at targeting (incl. which class each bacteria is in)? [3]
1. Streptococcus = gram +ve
2. Neisseria = gram - ve
3. Clostridium = anaerobe
45
How is amoxicillin administered? [1]
orally
46
Which bacteria are **amoxicillin** effective at targeting (incl. which class each bacteria is in)? [5]
1. Streptococcus = gram +ve
2. Enterococcus = gram +ve
3. Neisseria = gram -ve
4. Haemophilus = gram -ve
5. Clostridium = anaerobe
47
What is unique about flucloxacillin? [1]
it is a synthetic penicillin developed to be resistant to beta-lactamase produced by staphylococci
48
Which bacteria are **flucloxacillin** effective at targeting (incl. which class each bacteria is in)? [2]
1. Staphylococcus aureus (**except** MRSA) = gram +ve
2. Streptococci = gram +ve
49
Beta-lactamase inhibitors are combination drugs that are often co-admininstered with penicillin
Name 2 beta-lactamase inhibitors and state which drugs each are made of [4]
1. Clavulanic acid & amoxicillin = **co-amoxiclav**
2. Tazobactam & piperacillin = **tazocin**
50
Which bacteria are **co-amoxiclav** effective at targeting (incl. which class each bacteria is in)? [9]
1. Streptococcus = gram +ve
2. Enterococcus = gram +ve
3. Staphylococcus = gram +ve
4. Neisseria = gram -ve
5. Haemophilus = gram -ve
6. E. coli = gram -ve
7. Other coliforms = gram -ve
8. Clostridium = anaerobe
9. Bacteroides = anaerobe
51
Ceftriaxone is 3rd gen. cephalosporin antibiotic.
Which bacteria are ceftriaxone effective at targeting (incl. which class each bacteria is in)? [8]
1. Streptococcus = gram +ve
2. Staphylococcus (except MRSA) = gram +ve
3. E. coli = gram -ve
4. Neisseria = gram -ve
5. Haemophilus = gram -ve
6. Other coliforms = gram -ve
7. Clostridium = anaerobes
8. Bacteroides = anaerobes
52
Aztreonam is the only monobactam antibiotic out there.
Which bacteria are aztreoname effective at targeting (incl. which class each bacteria is in)? [5]
1. E. coli = gram -ve
2. Neisseria = gram -ve
3. Haemophilus = gram -ve
4. Pseudomonas = gram -ve
5. Other coliforms = gram -ve
53
Describe the mechanism of action of vancomycin [1]
Inhibits cell wall formation in Gram +ves only
54
How is vancomycin typically administered? [1]
administered intravenously (IV)
55
Which bacteria are vancomycin effective at targeting (incl. which class each bacteria is in)? [4]
1. Streptococcus = gram +ve
2. Staphylococcus = gram +ve
3. Enterococcus = gram +ve
4. Clostridium = anaerobe
56
What are the potential complications of vancomycin toxicity? [3]
1. Nephrotoxicity → more likely with higher doses
2. Red-man syndrome
* Occurs if injected too rapidly
* Anaphylactoid reaction
* Very rare now infusion rates slow
3. Ototoxicity (rare)
