Week 10

Question 1

Define antibiotic

Answer 1

Any substance that inhibits growth and replication of a bacterium or kills the bacterium.

Question 2

Antibiotics targets bacteria that are found where?

Answer 2

Within or on the body.

Question 3

Define antiseptics

Answer 3

Chemicals used to sterilise surfaces of living tissue when risk of infection is high.

Question 4

Define disinfectants

Answer 4

Non-selective antimicrobials used on non-living surfaces, kill a wide range of microorganisms.

Question 5

What are the general ways that antibiotic resistance can spread in bacteria?

Answer 5

Spontaneous mutation.

Taking up genetic material containing antibiotic resistant genes.

Question 6

When do spontaneous mutations occur that cause antibiotic resistance?

Answer 6

Mistakes are often made when copying bacterial DNA during binary fission. This leads to mutations that code for antibiotic resistance.

Question 7

What are the benefits of antibiotic resistant mutations?

Answer 7

They allow bacteria to survive where other bacteria die.

This can be passed on to successive generations.

Question 8

Name some reasons why antibiotic resistance is increasing

Answer 8

Uncontrolled use of antibiotics.

People vulnerable to infection living in small areas.

Overuse of antibiotics in animal husbandry.

Increase travel.

Question 9

How is bacterial resistance spread due to overuse of animal husbandry?

Answer 9

Spread via meat or can enter the environment.

Question 10

What is animal husbandry?

Answer 10

Breeding and caring for farm animals.

Question 11

How does increased travel aid bacterial resistance to antibiotics?

Answer 11

Allows spread of bacterial resistance to antibiotics globally rapidly.

Question 12

What was the original method for determining antibiotic sensitivity?

Answer 12

Grow some concentrations of bacteria with serial dilutions of antibiotic and determine the minimum inhibitory concentration.

Question 13

What were the issues with the original method of determining antibiotic sensitivity?

Answer 13

Very time consuming.

Question 14

When was the disk diffusion method of measuring antibiotic resistant discovered and who by?

Answer 14

Kirby-Bauer - 1956

Question 15

What is the purpose of the disk diffusion method?

Answer 15

To determine the sensitivity of bacteria to different antibiotics.

Question 16

What are the benefits of the disk diffusion method?

Answer 16

Can assess many antibiotics at once.

Question 17

What are the clinical uses of the disk diffusion method?

Answer 17

To determine the antibiotic treatment a patient may need.

Question 18

What the of agar is used in the disk diffusion method?

Answer 18

Mueller-Hinton

Question 19

How is the effect of different antibiotics on bacteria shown by the disk diffusion method?

Answer 19

Presence of absence of bacteria growth around a disk of paper impregnated with antibiotic is an indirect measure of antibiotic inhibition of bacterial growth.

Question 20

Outline the process used to form and carry out a Disk diffusion and what occurs to show antibiotic specificity.

Answer 20

1) Mueller-Hinton agar plate is inoculated with bacteria.
2) 6-mm filter paper disks are impregnated with known concentrations of antibiotic.
3) Mueller-Hinton agar - water absorbed into disk from agar - antibiotic diffuses into surrounding agar.
4) Concentration of antibiotic decreases as the distance from the disk increases.
5) Simultaneous growth of bacteria and diffusion of antibiotic.
6) Sharply marginated circle of bacterial growth at point where critical antibiotic concentration is reached. (Minimum inhibitory concentration

Question 21

What is the difference between an antibiotic and antimicrobial?

Answer 21

Antibiotics only target bacteria. Whereas antimicrobial is the umbrella term for anything that inhibits or kills microbial cells

Question 22

What type of antibiotic preparation is used to treat infections outside the body?

Answer 22

Creams or ointments

Question 23

What type of antibiotic preparation is used to treat infections inside the body?

Answer 23

Pills or liquids

Question 24

What type of antibiotic preparation is use to treat very serious infections?

Answer 24

Injection into the bloodstream

Question 25

Why are resistant strains of bacteria often harmful when they are inside the body?

Answer 25

They have more severe side effects and are often highly toxic.

Question 26

What are the different methods of resistance to antibiotics that bacteria can have and how do they work?

Answer 26

Reduce uptake into the cell. Activate efflux from the bacterial cell. Eliminate or reduce binding of the antibiotic to the target cell. Enzymatic Cleavage or modification to inactivate antibiotic molecule. Metabolic bypass of inhibited reaction. Overproduction of antibiotic target.

Question 27

Name the ways in which bacterial resistance can be passed on

Answer 27

Conjugation Transformation Transduction

Question 28

How is bacterial resistance passed on by conjugation?

Answer 28

When two bacteria are near each other, genetic material can be passed directly between cells or via pills or pores.

Question 29

What are DNA sequences that can more from one location on the genome to another by conjugation called?

Answer 29

Transposons

Question 30

How does bacterial resistance get passed on by transformation?

Answer 30

When a bacterium dies, it breaks up and releases its DNA into the environment. Nearby bacteria can pick up this floating DNA and integrate it into their own genomes.

Question 31

How does bacterial resistance get passed on by transduction?

Answer 31

When a virus attack a bacterium and takes over the host cell to makes copies of its self. Sometimes it's of bacterial DNA are included in the DNA of the virus particles produced. The viruses then carry these chunks of bacterial DNA to other bacteria they infect.

Question 32

Why must a patient complete an antibiotic course?

Answer 32

This ensures that as many bacteria as possible that are causing the infection are killed so that none are left to start a resistant bacterial population.

Question 33

Can antibiotics be used against the common cold?

Answer 33

No

Question 34

Why do antibiotics often lead to resistance when they are prescribed to patients whose prescription is unsure?

Answer 34

Broad-spectrum antibiotics are used which then interfere with many different bacterial types.

Question 35

How do antibiotics actually lead to resistance?

Answer 35

They create an environment which selects for resistant strains as they have large advantages over strains the are susceptible to antibiotics.

Question 36

Name some ways in which antibiotic stewardship is carried out.

Answer 36

Prevent infections that require antibiotic treatment by having good hygiene. Use antibiotics which are targeted and narrow-range. Develop better diagnostic method.

Question 37

How does producing better diagnostic methods reduce the spread of bacterial resistance?

Answer 37

More targeted, narrow-range antibiotics can be prescribed.

Question 38

Why are new antibiotics rarely produced?

Answer 38

Newly found antibiotics are often highly toxic. Have to go alot of testing which takes time and is expensive.

Question 39

What are the alternative methods of treatment of infection to antibiotics?

Answer 39

Bacteriophages Antivirulence drugs Bacteriocins

Question 40

What are bacteriophages?

Answer 40

Viruses that infect bacteria?

Question 41

What are the issues with using bacteriophages as a method to fight infections?

Answer 41

People don't like the idea of putting bacterial viruses into their body. Regulation of bacteriophages is very difficult.

Question 42

What are the advantages of using bacteriophages to fight infections?

Answer 42

More available than antibiotics. Very diverse. Bacteria-specific

Question 43

What is meant by bacteria-specific?

Answer 43

When bacteria become resistant, the phage will often evolve to re-infect it.

Question 44

How do anti virulence drugs work to fight bacterial infections?

Answer 44

They disable the specific proteins the bacterium uses to attach to host cells, preventing them from establishing infections.

Question 45

What are the issues than can arise from using antivirulence drugs to fight bacterial infections?

Answer 45

They disarm bacteria rather than killing them, so bacteria are still able to pass their genetic material on.

Question 46

What are bacteriocins?

Answer 46

Proteins produced by bacteria that are toxic to similar or closely related bacteria.

Question 47

What are the advantages of using bacteriocins to fight infection?

Answer 47

They have a narrow range. Can be used to delay food spoilage. Bacteriocins that attack pathogens are produced by bacteria that are harmless so would make ideal antibiotic substitutes.