Bacterial Genetics & Antibiotic Resistance

Front 1

5 ways bacteria resist antibiotics

Back 1

1) Degrade or alter antibiotics
2) Efflux pump
3) Uptake reduced
4) Overproduction of target metabolic bypass
5) Alteration of target

Front 2

How do bacteria degrade or alter antibiotics?

Back 2

-split beta-lactam ring
-modify aminoglycosides

Front 3

What types of antibiotics does the efflux pump effect?

Back 3

tetracyclines and macrolides

Front 4

What type of antibiotic has a reduced uptake in bacteria?

Back 4

cephalosporins

Front 5

What types of antibiotics are targeted for overproduction of target metabolic bypass?

Back 5

sulfonamides and timethoprim

Front 6

Which antibiotic is effected when penicillin binding protein is altered?

Back 6

beta-lactams

Front 7

Which antibiotic is effected when 50S ribosomal subunit is modified?

Back 7

macrolide

Front 8

Which antibiotic is effected by DNA gyrase and topoisomerase?

Back 8

fluoroquinolones

Front 9

How to pathogens develop resistance?

Back 9

Natural selection

Front 10

5 ways antibiotics are misused:

Back 10

1) Given when not needed
2) Continued when they are no longer necessary
3) Given at wrong dosage
4) Wrong antibiotic used to treat infection
5) Antibiotics purchased OTC leading to indiscriminate use

Front 11

Refers to a genetic change that is transferred from parent cell to offspring

Back 11

Vertical gene transfer

Front 12

Refers to the transfer of genetic material from one bacterium to another

Back 12

Horizontal gene transfer

Front 13

This type of transfer occurs though mutations

Back 13

Vertical gene transfer

Front 14

This type of transfer occurs though transformation, conjugation and transduction

Back 14

Horizontal gene transfer

Front 15

What is a change in the base sequence of a cell's DNA

Back 15

mutation

Front 16

These type of mutations are caused by mutagens (chemical, physical or biological)

Back 16

Induced mutations

Front 17

What kind of mutations result in antibiotic resistance?

Back 17

point mutations

Front 18

Transfer of naked DNA from a donor cell to a recipient cell is:

Back 18

Transformation

Front 19

Transfer of genetic material from one bacterium to another by means of a bacteriophage (virus) is:

Back 19

Transduction

Front 20

Transfer of DNA between bacterial cells by direct cell-to-cell contact (by a sex pilus) is:

Back 20

Conjugation

Front 21

What is it called when the new genetic material is integrated into the chromosome or plasmid of the host bacterium?

Back 21

Genetic recombination

Front 22

Occurs between closely related DNA sequences and generally substitutes one sequence for another

Back 22

Homologous recombination

Front 23

Occurs between dissimilar DNA sequences and generally produces insertions or deletions

Back 23

Nonhomologous recombination

Front 24

Requires enzymes provided by rec genes

Back 24

Homologous recombination

Front 25

Requires specialized (site-specific) recombinant enzymes such as those found in lysogenic bacteriphages and transposons

Back 25

Nonhomologous recombination

Front 26

Transfer of genes from one cell to another by means of naked DNA

Back 26

Bacterial transformation

Front 27

Bacterial transformation steps:

Back 27

1) Donor cells lyse and release free DNA
2) DNA attached to a recipient cell where it is cut into small pieces by nucleases and reduced to a single strand
3) Remaining strand integrates into the resident DNA by looking for a region of sequence homology
4) Invading strand replaces one of resident strands and undergoes replication

Front 28

A virus that replicates inside a bacterial cell is:

Back 28

A bacteriophage

Front 29

T/F: The phage nucleic acid takes over the cell's biosynthetic machinery to replicate its own genetic material

Back 29

True; it then synthesizes phage specific proteins

Front 30

This type of phage multiplies with the cell and results in lysis and release of phage particles

Back 30

Virulent phage

Front 31

This type of phage enters the cell and integrates into specific sites within the host bacterial chromosome

Back 31

Temperate phage

Front 32

T/F: Temperate phage genes are repressed and the phage DNA replicates as part of the host chromosome

Back 32

True

Front 33

T/F: After induction, the temperate phage undergoes the normal lytic cycle

Back 33

True

Front 34

This type of transduction transfers any bacterial gene

Back 34

Generalized transduction

Front 35

This type of transduction transfers only genes adjacent to site of integration of a lysogenized temperate phage

Back 35

Specialized transduction

Front 36

Steps of generalized transduction

Back 36

1) random fragment of bacterial DNA is accidentally encapsulated in a phage protein coat
2) when this particle infects a new host cell it injects the bacterial DNA fragments into the cell
3) New DNA can become integrated into the host chromosome by recombination

Front 37

Steps of specialized transduction

Back 37

1) After induction genes located next to the prophage may be excised and replicated along with the phage DNA
2) When the phage infects another cell both chromosomes and phage DNA integrates into the new recipient

Front 38

Steps of conjugation

Back 38

1) Certain plasmids (F) can transfer themselves
2) Donor cell makes a sex pilus that makes contact with receptor sites on the recipient cell
3) Pilus retracts into the donor cell bringing donor and recipient into close contact (no evidence that DNA passes through this tube)

Front 39

T/F: During conjugation the F plasmid never integrates itself into the bacterial chromosome

Back 39

False

Front 40

During conjugation, when the plasmid is transferred to another cell it drags along the _____ with it

Back 40

chromosome

Front 41

During conjugation, integration into the recipient cell occurs how?

Back 41

Homologous recombination

Front 42

Conjugative Resistance (R) Plasmids are found in what type of bacteria?

Back 42

Gram-negative

Front 43

Conjugative Resistance (R) Plasmids contain what?

Back 43

F factor and resistance genes often coding for multiple resistance

Front 44

Structure of R plasmid

Back 44

RTF (Resistance Transfer Factor) carries the replication and transfer genes (F)
R determinant -contains multiple transposons with resistance genes

Front 45

Resistance genes are often parts of what?

Back 45

Transposons

Front 46

Another name for transposons

Back 46

Jumping genes

Front 47

T/F: Transposons can move from place to place on the chromosome and into and out of plasmids

Back 47

True

Front 48

T/F: Transposons do not carry genes coding for resistance

Back 48

False; they carry insertion sequences and genes coding for resistance

Front 49

T/F: If transposon inserts into a functional gene it will be destroyed resulting in cell death

Back 49

True

Front 50

Transposons are considered to be:

Back 50

a biological mutagen

Front 51

These are often contained within transposons; they can capture multiple gene clusters

Back 51

Integrons

Front 52

What are cassettes?

Back 52

Multiple gene clusters

Front 53

What do integrons do?

Back 53

integrate gene cassettes into the genome

Front 54

What do integrons consist of?

Back 54

a 2 component gene capture and expression system

Front 55

Allows a number of different resistance genes to be transferred as a unit from one bacterium to another

Back 55

Integrons

Front 56

5 means of antibiotic resistance

Back 56

1) overuse of antibiotics
2) R plasmid
3) Transposons/Integrons
4) Spontaneous mutations
5) Other means of horizontal gene transfer

Front 57

5 solutions to antibiotic resistance

Back 57

1) Reduce antibiotic usage
2) Develop new class of antibiotics and vaccines
3) Contain resistance in the hospital
4) Build alliances and partnerships to decrease access to antimicrobials
5) Fund research that might provide a better understanding of the genetics of resistance