Week 8 Y

Question 1

Sensitivity

Answer 1

Ability to detect a true positive

Question 2

Specificity

Answer 2

The ability to test for a true negative

Question 2

Name types of culture methods

Answer 2

General purpose, selective, differential, chromogenic

Question 2

Microscopy advantages and disadvantages

Answer 2

Fast, cheap specificity possible

Poor sensitivity, can’t recover organisms

Question 3

Advantages + dis of culture

Answer 3

Cheap, shows antigen well, pathogen can be analysed further

Slow, difficult to culture some pathogens

Question 4

Immunodiagnostics tests

Answer 4

Agglunitation
ELISA

Question 5

Antibiotics

Answer 5

Inhibits the growth of micoorganisms

Question 6

Bacterialcidal

Answer 6

Kills bacteria

Question 7

Bacteriostatic

Answer 7

Stops growth, doesn’t kill bacteria, can grow back again

Question 8

Minimum inhibitory concentration

Answer 8

lowest concentration of the antibiotic that results in
inhibition of visible growth under standard conditions.

Question 9

Selective toxicity

Answer 9

More damage to bacterium than host

Question 9

Synergy

Answer 9

If two antibiotics used in
combination has an antibacterial effect much
greater than either drug alone

Question 9

How resistance is transferred via horizontal gene transfer

Question 9

How the inactivation of a drug works

Answer 9

Enzymes are produced by microbes which degrade the drug, neutralising it, e.g beta-lactamase

Question 10

How drug targets are duplicated

Answer 10

The microbe produces additional copies of the drug target, diluting the drug’s effect as it binds to only a subset of the targets.

Question 10

Conjugation

Answer 10

Involves the direct transfer of genetic material between bacteria via a pilus (a tube-like structure).

Question 10

How drug permeability is reduced

Answer 10

The microbial cell reduces the uptake of the drug by altering membrane permeability or reducing the number of drug-specific porins, e.g gram negative bacteria

Question 10

How modification of drug target works

Answer 10

Microbes alter the structure of the drug’s target site, reducing or eliminating the drug’s binding affinity

Question 10

Transformation

Answer 10

Bacteria take up free DNA from their environment, often from lysed (broken) cells, incorporated into dna

Question 11

Absence of drug target

Answer 11

The microbe naturally lacks the specific structure or pathway targeted by the drug, making it inherently resistant.

Question 11

Name the 3 HGT mechanisms

Answer 11

Transformation, transduction and conjugation

Question 12

Transduction

Answer 12

A bacteriophage transfers genetic material between bacteria.
bacterial DNAmay accidentally be packaged into a phage particle.
When this phage infects another bacterium, it injects the resistance gene into the recipient, which may integrate it into its genome or plasmid.

Question 13

Conjugation

Answer 13

Involves the direct transfer of genetic material between bacteria via a pilus

Requires cell to cell contact

Can transfer ARG across to GP+N bacteria

Question 14

The importance of the environment in ARGs

Answer 14

Site of Antibiotic resistance

Promotes evolution of ARGs and can create drug-resistant organisms

Question 15

Advantages of cultivation as a diagnostic tool

Answer 15

Direct observation, only living organisms, low cost, can find the CFU

Question 16

Disadvantages of cultivation as a diagnostic tool

Answer 16

Time consuming, not suitable for all organisms, labour-intensive

Question 17

What is the goal of biochemical testing

Answer 17

Identifies colonies growing, ensures it’s the right one as colonies have overlapping features e.g lactose fermenter with E.coli

Question 18

What is the goal of immunological testing with an example

Answer 18

Identifies and confirms an organism by using an antigen and antibody e.g Staphylococcus aureus on Mannitol Salt Agar

Question 19

maldi-tof stands for

Answer 19

matrix assisted laser desorption ionization-time of flight mass spectrometry