Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ASC306 > Antibiotics I > Flashcards

Antibiotics I Flashcards

1
Q

What does penicillin inhibit?

A

Cell wall peptidoglycan synthesis

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

What happens when disruption of the peptidoglycan wall occurs?

A

Osmotic lysis of the bacterium

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

What causes ‘Hotspot’ in dogs?

A

Staphylococcus

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

Beta lactam antibiotics …

A

Contain a beta lactam ring in their molecular structures. Inhibits cell wall biosynthesis in the bacterial organism.

Beta lactams are hydrophilic, they do not like crossing membranes.

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

Targeting bacterial peptidoglycan is an example of what?

A

Selective Toxicity

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

What is the most commonly used beta-lactamase inhibitor?

A

Clavulanic acid eg amoxycillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Beta-Lactam Antibiotics

What are natrual penicillins predominatly active against?

A

Gram +ves and anaerobes, but some very important gram -ves also

incl pasteurella, streptococcus, and clostridia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Beta-Lactam Antibiotics

What are aminopenicillins active against?

A

predom G+ve & anaerones, some important G-ve’s

Same as penicillin, but with better penetration (pKA related) into tissues/bacteria. eg amoxycillin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Beta-lactam Antibiotics

What are first gen cephalosporons active against?

A

Gram +ive, successive generations have increased activity against Gram-negative bacteria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Beta-Lactam Antibiotics

Why does first gen cephalosporins have excellent activity against staphylococcus

/

A

B-lactam ring is structually resistant to B lactamase.

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

Beta-Lactam Antibiotics

Third gen cephalosporins active against?

A

Further improved gram neg but reduced gram pos activity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the t1/2 of B-lactams?

A

approx 1hr

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

How safe is B-lactamans in regards to toxicity and what can it be used in?

A

Verysafe.

Geriatrics, juveniles, pregnancy and during lactation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the side effects of B-lactams and how do they come about?

A

Usually come about through a dysbiosis

  • killing good bacteria
  • recolonisation by a monomorphic population
  • toxins
  • GIT signs

Diarrhoahea, vomitting most common side effects

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

A bit about Procaine Penicillin?

A
  • Kills streptococcus, clostridia and pasteurella
  • Excellent anaerobic efficacy
  • Does not work against b-lactamase producing bacteria
  • Convient dosing (sid)
  • Never IV
  • Low LD50 esp in horses
  • Prescribed commonly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the procaine used for in penicillin?

A

An insoluble salt

17
Q

What can procaine do to a horse’s brain?

A

Inhibits neural conduction in inhibitory inter-neurons

18
Q

A bit about amoxicillin - clavulanic acid

A
  • excellent anaerobic efficiacy
  • works against b-lactamase producing bacteria
  • convient dosing (sid or bid)
  • good distribution to most tissues
  • not good for abcesses, pneumonia and mastitis
  • Never IV
19
Q

What happens if you give a small animal oral beta lactam?

A

Destroys normal gut flora, overgrowth of clostridum difficile, toxin production.

20
Q

Give a summary of Aminoglycosides

A
  • 30S ribosome target
  • Gram neg mostly
  • Doesnt kill anaerobes
  • SID dosing
  • Synergy with b-lactams
  • Poor oral absorption
  • Vestibular ototoxicity
  • Nephrotoxicity
21
Q

What is one of, if not the most commonly used antibiotic classes for production animals?

A

Tetracyclines

22
Q

What is the mechanism of action of the ocytetracycline?

A

Binds to ribosomes and inhibits protein synthesis

23
Q

A bit about tetracyclines?

A
  • broad spectrum
  • long t1/2 (12hrs)
  • excellent distribution
  • 50:50 hepatic: renal metabolism
  • out of date solutions are toxic
  • large animal use mostly
24
Q

Name the two classes of beta lactams

A
  1. penicillins
  2. cephalosporins (more resistant to breakage)
25
Q

Who is more susceptible to beta lactams and why?

gram +ve or gram -ve?

A
  • gram +ve more susceptible as more peptidoglycan and not as well protected
  • Gram -ve has more membrane so better protected.
    cell wall double lipid membrane structure, porins less permeable to BL.
26
Q

What do beta lactamases do?

(enzymes present in resistant bacteria)

A

hydrolyse beta-lactam ring (except cephalosporins)

27
Q

How do beta-lactamase inhibitors work?
MOA

A
  • Use a second beta-lactam that will bind (preferrentially as greater affinity for enzyme) to the beta-lactamase
  • and therefore spare the first (and more clinically efficacious) beta-lactam
28
Q

Describe the pharmacokinetics of b-lactams

A
  • hydrophilic
  • weak acids
  • good distribution except in pneumonic lung and absceses (abscess due to acidic enviro)
  • renal elimination

ASC306 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions