Advanced Microbiology - Prevention and Control

Question 1

Chain of infection (6)

- can intervene at each step to prevent spread of infection

Answer 1

Pathogen –> reservoir –> exit –> mode of transmission –> entrance –> host –> pathogen spread

Question 2

Decontamination includes? (in order of severity)

Answer 2

Cleaning, Disinfect and Sterilisation

Question 3

Decontamination VS anti-sepsis

Answer 3

BOTH to eliminate pathogen

BUT anti-sepsis is when applied to living tissue

Question 4

Disinfectant VS sterilization

Answer 4

Disinfecting = removal of sufficient number of potentially harmful organisms eg. surfaces and spills

Sterilization = complete killing of all types of micro-organism particularly C. diff vegetative spores.

Question 5

Methods of Sterilisation (4)

Heat has 2 types

Answer 5

Heat

• Moist = in autoclave high pressure steam and temp
• Dry = oven

Chemical - gas (H2O2) or liquid

Filtration

Ionising radiation (single use disposable equipment)

Question 6

Methods to ‘remove the reservoir’

Answer 6

Hand washing and decontamination

Question 7

When to hand wash? + most important

By either alcohol gel or soap and water

Answer 7

Before contact
*Before aseptic task 
*after bodily fluid exposure
after patient contact
After contact with patient surroundings

Question 8

Methods to minimize transmission (4)

Answer 8

Hand washing and PPE (personal protection equipment)
Decontamination
Sterilisation of equipment OR single use
Source protection and isolation

Question 9

Methods to eliminate exit and entrance?

Answer 9

treatments

Question 10

Methods to protect the susceptible host?

Answer 10

Vaccinations

Question 11

Which decontamination method to use is based on?

Answer 11

Risk of infection
Physical properties of equipment being used
Chemical properties of cleaning product
Physical properties of cleaning product 
harmful effects of cleaning product

Question 12

How should we clean: items that enter sterile parts of the body or break the skin?

Answer 12

STERILISE

Question 13

how should we clean: items that come in contact with mucous membranes or bodily fluids

Answer 13

DISINFECT

Question 14

how should we clean: items that come in contact with unbroken skin

Answer 14

CLEAN

Question 15

Diseases with vaccines against them (17)

Answer 15

Polio
Mumps
Diphtheria
Tetanus
Rubella
Measles
Acute meningitis (ACWY)
Meningococcal Septiceamia 
Whooping cough
HPV 
Hep A, B and C
Typhoid 
TB (BCG injection)
Anthrax
Yellow Fever
Varicella Zoster
Flu

Question 16

Passive immunity? two types

Last a few weeks

Answer 16

Vertical transmission of Antibodies from mother to child

HNIG - plasma injections with specific antibodies

Question 17

Active Immunity? two types

Lasts a long time

Answer 17

Infection - body creates the antibodies + plasma cells = memory
Vaccination - creates antibodies without disease occuring

Question 18

Examples of Live vaccinations? (4)

Answer 18

MRR, BGC, Varicella, yellow fever

Question 19

Attenuated pathogen? - what does it mean

Answer 19

been weakened so still invade the host but don’t cause the disease (virulence reduced)

Question 20

Inactivated Vaccinations examples? (8)

Answer 20

Pertussis
Influenza
Rabies
Hep A
Typhoid 
IPV
Diphtheria
HIB - heamophillus influenza type B

Question 21

Suspensions? inactivated vaccines?

Answer 21

whole intact dead organism - with antigens which stimulate antibody production

Question 22

Acellular sub unit vaccinations?

Answer 22

Part of the dead organism (just the antigens)

Question 23

Susceptible population?

Answer 23

any one not immune to particular pathogen

• not encountered the infection
• not had the vaccination (counter indicated for them)
• unable to amount an immune response (immunosupressed)

Question 24

Active VS inactive vaccination (2 for and 2 against for both)

Answer 24

Live = single does sufficient, strong immune response

BUT counter indicated for immunosupressed and could turn virulent

Inactive = Several doses, shorter acting, local reaction

BUT Stable constituents and not able to cause an infection