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Question 1

What are the differences in the cell walls of gram positive and gram negative bacteria?

Answer 1

Gram postive has three layersGram negative have five layers – has an outer membrane of lipopolysaccharide– has two layers of periplasmic membrane

Question 2

What different types of fungi are there?

Answer 2

Single celled – CandidaMulticellular – Aspergillis

Question 3

What are bacteriophages?

Answer 3

Viruses which parasitise bacteria by injecting in their DNA

Question 4

What is characteristic about bacterial DNA?

Answer 4

Have circular DNA which gets wound up completely and is not enclosed in a nuclear envelope/free in the cytoplasm

Question 5

Describe plasmids

Answer 5

DNA which are not part of the main bacterial DNA which are able to transfer genetic material from one bacteria to another.

Question 6

Define pharmacokinetics

Answer 6

What the body does to the drug

Question 7

What in the body determines the concentrations of drug in the blood and tissue?

Answer 7

1. Route of administration2. Method of distribution3. Rate and method of elimination or metabolism

Question 8

Why is pharmacokinetics important?

Answer 8

Drugs can work well against neisseria meningitids (infects meninges) but may not be able to get through the BBB so would be ineffective.

Question 9

Define pharmacodynamics

Answer 9

What the drug does to the micro-organisms

Question 10

What are the two main type of antibiotics?

Answer 10

Time dependent killing antibioticsandConcentration dependent killing antibiotics

Question 11

Describe time dependent killing antibiotics

Answer 11

Successful treatment requires a prolonged antibiotic presence at the site of infection but you do not need a high concentration- just above MIC for 24 hours

Question 12

Describe concentration dependent killing antibiotics

Answer 12

Successful treatment requires a high antibiotic concentration at the site of infection- high Cmax:MIC ratio at one point during the day

Question 13

What is Cmax?

Answer 13

The maximum concentration of the antibiotic

Question 14

What is MIC?

Answer 14

Minimum inhibitory concentration– the minimum concentration of the antibiotic needed to have an effect on the bacteria

Question 15

Describe Therapeutic drug monitoring

Answer 15

Take a blood sample at certain intervals in order to make sure that the concentration of drug in the blood is within a sufficient range (therapeutic window)

Question 16

How do you measure antibiotic activity?

Answer 16

Disc sensitivity testingE-tests

Question 17

What is an E test?

Answer 17

A laboratory test which allows you to determine if the bacteria is susceptible to a particular antibiotic and to what concentration it is susceptible to.

Question 18

What are the two ways that bacterial resistance can develop?

Answer 18

Chromosomal gene mutationHorizontal gene transfer

Question 19

Descrive chromosomal gene mutation

Answer 19

Mutation occurs in one chromosome which gains resistance. When it is exposed to antibiotics, it will survive and then pass on its mutation and therefore its resistance.

Question 20

Describe horizontal gene transfer

Answer 20

DNA can enter the cell by:- bacteriophages- plasmids- free DNAThis DNA is the integrated into the bacteria’s DNA which means that is has integrated the DNA which gives resistance into tis own DNA

Question 21

What are the specific changes that occur in bacteria that give it antimicrobial resistance?

Answer 21

1. Inactivate beta-lactamase enzyme2. Alter target site, so antimicrobial cannot bind to the cell3. Metabolic pathways are altered4. Decreased permeability of bacterial cell5. Active efflux mechanism – get antimicrobial out of the bacteria as quickly as possible

Question 22

How can you avoid antimicrobial resistance?

Answer 22

1. Antimicrobial stewardship- use the right antibiotic a the right time with the right dose, frequency and duration through the correct route2. Infection control

Question 23

How can you prevent antibiotic resistance?

Answer 23

1. Prevent bacterial exposure to antibiotics- minimise risk of infection- monitor and control antimicrobial prescribing2. Prevent the spread of recognised resistant bacteria- isolation or cohorting- hand hygiene- decolonisation of patient (disinfectant body wash)

Question 24

Give some other characteristics of bcteria

Answer 24

Ribosomes are smaller in bacteria than eukaryotesContain plasmids