L14: Dissemination of Abx Resistance Genomes II

Question 1

How do bacteria acquire resistance?

Answer 1

Acquire large pieces of DNA from other bacteria or phages

Question 2

What are hte modes of genetic exchange?

Answer 2

Transformation
Conjugation
Transduction

Question 3

What is transformation?

Answer 3

Naked DNA released by donor cell via lysis

Naked DNA is taken up by competent recipient cell

Question 4

What is competence?

Answer 4

Ability of bacterial cell to take up DNA from environment

Question 5

What are the risks of naked DNA?

Answer 5

Susceptible to degradation to environmental factors like detergent or nucleases

Question 6

What is the form of the naked DNA as it enters the recipient?

Answer 6

Single stranded through pore

Question 7

What happens to the naked DNA after being taken up by a cell?

Answer 7

Circularize -> lost by dilution
Degradation
Recombination into chromosome

Question 8

What is conjugation?

Answer 8

Donor reaches out to recipient cell with sex pilus -> pull cell in -> makes pore-> can transfer DNA through in a rolling mechanism

Question 9

What are the clinical relevance of conjugation?

Answer 9

Rapid dissemination of drug resistance via conjugal R plasmids or conjugal transposons

Interspecies transfer

Normal flora can act as resistance reservoir`

Question 10

What mediates transduction?

Answer 10

Bacteriophage