L13: Dissemination of Abx REsistance Genomes I

Question 1

What are hte types of genome found within a bacteria?

Answer 1

Chromosomal
Plasmid
Phage

Question 2

What is a plasmid?

Answer 2

Autnomous, self replicating, extrachromosomal double stranded DNA that is easily transferred from host to host

Question 3

What are conjugative plasmids?

Answer 3

F/R plasmids that can autonomously transfer themselves from 1 host to another

Question 4

What are nonconjugative plasmiids?

Answer 4

Plasmids that cannot autonomously transfer themselves but can recombine with a conjugative plasmid and be transferred in thatway

Question 5

What does the bacteriophage genome carry?

Answer 5

Virulence factors

Ex: Diptheria, Cholera

Question 6

What happens in a lytic infection?

Answer 6

Phage replicates itself within the host -> lyses host cell -> release progeny

Question 7

What happens in a lysogenic infection?

Answer 7

Phage becomes latent and becomes a prophage -> can circularize or integrate into host chromosome

Can potentially convert to lytic stage if stimulus present

Question 8

What are transposable elements?

Answer 8

Genetic units that mediate their own transfer from 1 location to another within the same genome or from 1 genome to another WITHIN the same cell

Question 9

What are the types of transposable elements?

Answer 9

Insertion sequence
Transposons
Transposable Prophages
Conjugal Transposon

Question 10

What are insertion sequences?

Answer 10

Segments of genes that carry only genes for transposition recombinase and inverted repeats

Question 11

What are transposons

Answer 11

transposable elements with genes for transposition as well as other functions

IS-Gene-IS

Question 12

What is a transposable prophage?

Answer 12

Bacteriophage that can transpose within the host

Question 13

What is a conjugla transposon

Answer 13

Transposon with the ability to transpose within a cell as well as to other cells via conjugation

Question 14

What are R plasmids?

Answer 14

Plasmids that often carry genes conferring multiple abx resistance

Genes:
Inactivate abx
REduce permeability to abx

Question 15

How for can selection for non-selected resistance occur?

Answer 15

A cell may take up R plasmid with a multiple abx resistant cassette -> if this cell is resistant to an administered abx -> it will survive and grow in the new niche left behind by the dead cells -> this will select for all the other abx resistant genes within the cassette as well -> thus you end up with selection for multiple abx resistance through just 1 abx