Session 2 - Infection Model Flashcards Preview

ESA 3 - Infection and Immunity > Session 2 - Infection Model > Flashcards

Flashcards in Session 2 - Infection Model Deck (27)
Loading flashcards...
1
Q

Give 2 examples of Viruses, Bacteria, Fungi (yeast and mould) and Parasites (protozoa and helmniths)

A

Viruses – HIV, HPV, influenza,

Bacteria – E. coli, staph aureus

Fungi:

a) Yeast – Candida albicans (vaginal flora), cryptococcus neoformans
b) Mould – Aspergillus, dermatophytes (e.g. athletes foot)

Parasite:

a) Protozoa – Trypanosoma cruzi, Cryptosporidium parvum
b) Helminth (worm) – Tape worm, roundworms, flukes

2
Q

How can you assess the minimum inhibitory concentration required to kill bacteria?

A

Minimum inhibitory concentrations can be assessed by placing a varying concentration of the antibiotic in a number of vials containing the bacteria and seeing what the smallest amount of concentration is needed to kill the bacteria. Usually assessed by having the vial change colour in the presence of bacteria.

3
Q

What 3 ways can render an antibiotic no longer effective against an MO?

A

a) Drug inactivating enzymes produced, e.g. beta lactamases
b) Altered target – target enzyme develops lower affinity for antibiotic
c) Altered uptake – either an increase in the efflux of the drug or a decrease in the permeability of the membrane to the antibiotic

4
Q

What are the 2 ways a bacteria can gain resistance?

A

1) Chromosomal gene mutation – A mutation In the genetic material encoding the target enzyme results in an altered enzyme which the drug is less able to impact
2) Horizontal gene transfer – Transposons (parts that be transferred between plasmids or between plasmids and chromosomes) can move from one organism to another by 3 processes:
a. Conjugation – Resistance passing from one organism to another by direct transfer
b. Transduction – A vector, usually a phage, picks up the transposon from one bacteria and gives it to another.
c. Transformation – free sections of DNA can transfer from one bacteria to another by crossing the PM

5
Q

What are the 4 areas that an antibiotic can act on?

A

Cell wall synthesis, protein synthesis, cell membrane function, nucleic acid synthesis

6
Q

What are the 2 types of AnB attack cell wall synthesis?

A

BCG

Beta lactams

Cell wall synthesis

Glycopeptides

Beta lactams and glycopeptides

7
Q

What 3 types of AnB attack protein synthesis?

A

TAMPon

Tetracyclines
Aminoglycosides
Macrolides
Protein Synthesis

on

Tetracyclins, aminoglycosides, and macrolides

8
Q

What type of AnB attacks cell membrane function?

A

Child Pornography

Cell membrane

Polymixins

Polymixins

9
Q

What type of AnB attacks nucleic acid synthesis?

A

NewQuay

Nucleic acid synthesis

Quinolones

Quinolones

Tampons, BCG and Child pornography in NewQuay

10
Q

What is the mechanism of action of penicillin?

A
  • Cross linkage between cell walls achieved by penicillin binding protein
  • Penicillin gets into penicillin binding protein and blocks enzyme from forming cross links
11
Q

What is the mechanism of action of vancomycin?

A

• Sits on the peptide chains that cross link and stops the penicillin binding proteins from binding and forming cross links.

12
Q

What is the mechanism of action of fluoroquinolones?

A

• Bind to two nuclear enzymes and inhibit DNA ligase and therefore replication

13
Q

Name the 4 categories of beta lactams

A

1) penicillins
2) cephalosporins
3) carbapenems
4) monobactams

14
Q

What are cephalosporins used for? give example

A

Broad spectrum and c difficile. e.g. ceftriaxone

15
Q

What are carbapenems used for? give example

A

Broad spectrum gram -ve, safe for penicillin allergy e.g. meropenem

16
Q

Give 3 types of penicillin and what they are used for

A

o Penicillin – used against streptococci

  • Amoxicillin – Used against gram negatives
  • Flucloxacillin – against staphylococci and streptococci
17
Q

What is vancomycin used for? What type of AnB is it?

A

MRSA. Glycopeptide.

18
Q

Give an example of a tetracycline AnB. What is it used for?

A

Penicillin allergy against gram +ve bac

19
Q

Give an example of an aminoglycoside. What is it used for?

A

Gentamicin – gram –ve

20
Q

Give example of quinolone and use.

A

Ciprofloxacin – gram-ve

21
Q

Give example of macrolide and use.

A

Erythromycin – gram +ve, alternative to penicillin

22
Q

What treatment is given for UTIs? What about in cases of MRSA UTI?

A

Trimethoprim. MRSA - Trimethoprim + Sulphonamide

23
Q

What are the two categories of antifungals?

A

azoles and polyenes

24
Q

How do you treat herpes simplex?

A

Aciclovir

25
Q

How do you treat influenza a and b?

A

tamiflu

26
Q

What is an antimicrobial stewardship?

A
  • Selecting an appropriate drug and optimizing its dose and duration to cure an infection
  • Minimizing toxicity and conditions for selection of resistant bacterial strains.
27
Q
A