Antimicrobial Therapy

Question 1

Define bactericidal and bacteriostatic.

Answer 1

• Bacteriostatic; a biochemical agent which inhibits bacterial growth without killing the bacterium
• Bactericidal; agent which kills the bacterium

Question 2

Define MIC.

Answer 2

MIC; minimum inhibitory concentration.

Question 3

Brief outline of antibiotic history.

Question 4

What are the sources of antibiotics?

Answer 4

Antibiotics are sourced from (1) moulds or fungi (2) other bacteria [e.g. Bacillus] (3) synthetic or semisynthetic.

*Used internally or topically to inhibit/kill pathogens. Work best on actively goring organisms NOT on non-growing persisters or spores.

Question 5

Define antibiotic resistance and what causes it.

Answer 5

AMR is the ability of bacterium to resist the facts f an antibiotic which had previously been effective in inhabiting to killing the bacterium at a given concentration.

Causes of AMR include over prescribing antibiotics, patients not finishing treatment, poor hygiene, lack of new research, etc…

Question 6

What are the advantages and disadvantages of phage therapy?

Answer 6

Adv.
- Specific to bacterial species
- Naturally occurring
- Active against resistance bacteria

Disadvantages
- Can develop phage-resistance
- Transduction
- Phage neutralising antibodies

Question 7

List and outline the type of culture media used for traditional bacterial growth.

Answer 7

Differential; contain compounds that allow microorganisms to be visually distinguished by colony morphology/the surrounding media(e.g. blood agar).
Selective; contains ingredients that inhibit the growth of some microbes bur allow other to grow(e.g. mannitol salt agar).
General; is non-selective and supports a range of microorganisms with non-complex growth.

Question 8

What makes a good or bad one? What should be considered about antibiotics?

Answer 8

Effective antibiotics must be soluble in bodily fluids, selective toxicity, stable, non-allergic, etc…

Points to consider are if said antibiotic should inhibit a bacterium or kill it(bacteriostatic or bactericidal), what’s the MIC?, etc

Question 9

Draw the general antibiotic targets in bacterium.

Question 10

Summarise the mechanism of resistance(VOD).

Question 11

Tabulate a summary of traditional diagnostic tests.

Question 12

Define nuclei acid tests(a molecular technique) and give examples.

Answer 12

A nucleic probe is a sequence of nucleotides with a label attached. the label is used to track what happens to the probe. The probe sequence will bind in a highly selective manner to a single strand of nucleic acid with a complementary sequence. (E.g. PCR, ELISA, 16S, etc…)

Question 13

Brief notes on 3 nuclei acid tests. (Include what they’re used for and their respective mechanisms)

Answer 13

PCR;
ELISA;
16S Ribosomal RNA Sequencing;