Determining AMR and Horizontal gene transfer (L4)

Question 1

what is the Objective of susceptibility testing

Answer 1

Determine the minimum inhibitory concentration (MIC) of an antibiotic for a specific clinical isolate

Question 2

what does MIC mean

Answer 2

MIC = lowest concentration of antibiotic which has inhibited growth

Question 3

give me an example of suspectibaility testing for agar

Answer 3

Agar dilution method
Disk diffusion
E-test

Question 4

give me an example of susepctaibility testing for broth

Answer 4

Microdilution
Macrodilution

Question 5

Considerations when performing susceptibility testing

Answer 5

Mixed culture may have both a susceptible and resistant isolate

Number of cells in an inoculum
-To few may give un readable results or false negative
-To many may give a false-resistant result

Question 6

what is Vertical gene transfer (VGT)

Answer 6

is the transfer of genetic material from parent cell to daughter cell

Question 7

what is Horizontal gene transfer (HGT)

Answer 7

is the transfer of DNA from a donor cell to a recipient cell

Question 8

Why exchange DNA?

Answer 8

Improves the competitiveness of a cell under specific environmental conditions

This advantage can then be passed on to descendants via vertical transmission

Question 9

what is transformation

Answer 9

Many bacteria can import naked DNA released from nearby dead cells or plasmids

Question 10

Naturally competent - transformation

Answer 10

Natural transformation is conferred by specific protein complexes calledtransformasomes

Gram-positive bacteria
-Streptococcus andBacillus
Gram-negative species
-HaemophilusandNeisseria
.

Question 11

Artificially competent- transofrmation

Answer 11

Require artificial manipulations to drive DNA into their cells

E. coliandSalmonella,do not possess the equipment needed to import DNA naturally.

Question 12

Natural Transformation

Answer 12

Formation of the transformasome makes bacteria competent for DNA uptake.

Binding proteins capture extracellular DNA.

Proteins form a pore in the membrane for DNA entry.

Nucleases degrade unwanted DNA strands.

Recombination incorporates the desired DNA into the bacterial chromosome

Question 13

what is Conjugation

Answer 13

The transfer of genetic material between bacterial cells by direct cell-to-cell contact through a bridge-like connection (pilus) between two cells.

Question 14

describe plasmids

Answer 14

Found in Bacteria
DNA molecule, usually double stranded, replicates independently to chromosome

Question 15

summary of antibiotics suspecitbility testing

Answer 15

Important for determining the correct antibiotic therapy

Question 16

summary of transfer of genetic material

Answer 16

Genetic information in bacteria can be transmitted either vertically or horizontally

There are three primary methods of horizontal gene transfer