Transmission of infection

Question 1

What is virulence

Answer 1

The ability of the microbe to cause disease

Question 2

What is dose

Answer 2

The number of microbes entering the body

Question 3

What is ID50

Answer 3

Infectious dose 50 (how an infectous dose is expressed)

Question 4

What is the infectios dose of TB

Answer 4

1 bacillus

Question 5

What is the infectous dose of Syphilis

Answer 5

57 bacteria

Question 6

What is the incectious dose of E. coli 0157

Answer 6

<10 cfu

Question 7

What is the infectious dose of influenxa virus

Answer 7

<10 (tissue culture ID50)

Question 8

What does a low ID50 indicate

Answer 8

More infectious

Question 9

What makes a device/instrument critical (high risk)

Answer 9

Items in contact with normally sterile body sites

Question 10

What are examples of high risk instruments

Answer 10

foreceps, periodontal scaler

Question 11

Why is an instrument semi critical (spaulding clacification)

Answer 11

It has been in contact with intact mucous membrane

Question 12

What is an example of a semi critical device/instrument

Answer 12

Dental handpiece

Question 13

What does the title noncritical (low risk) indicate

Answer 13

The object has been in contact with intact skin

Question 14

What is a non-critical object

Answer 14

light cure

Question 15

What does minimal risk indicate

Answer 15

Items not normally in contact with intact skin

Question 16

What is a minimal risk object in the dental setting

Answer 16

Dental chair

Question 17

How are minimal risk objects cleaned

Answer 17

Decontaminated using detergent/antibacterial wipes

Question 18

How are low riskobjects cleaned

Answer 18

Some are placed in a washer disinfector with the semi-critical and critical instruments however some, such as light cure, can be decontaminated using antibac wipes etc

Question 19

What is a non-critical environment surface called

Answer 19

Housekeeping surfaces

Question 20

What are examples of household surfaces (not directly touched suring treatment)

Answer 20

Walls
Hand sink
Floor

Question 21

What is the definition of clinical contact surfaces

Answer 21

Contaminated area from patient materials either by direct spray or splatter generated during dental procedures ​

OR ​

By contact with gloved hands of dental health care personnel

Question 22

What are examples of clinical contact surfaces

Answer 22

Light handle
Worktop
Spitoon and tubing
Drawer handles

Question 23

What is the most common pathway of indirect transmission

Answer 23

Through poor hand hygeine
-Touching contaminated surface and then the susceptible patient

Question 24

What is the definition of cleaning

Answer 24

A process which physically removes infectious agents and the organic matter on which they thrive but does not necessarily destroy infectious agents​

The reduction of microbial contamination depends upon many factors, including the effectiveness of the cleaning process and the initial bioburden​

Cleaning is an essential prerequisite to ensure effective disinfection or sterilisation.​

Routine cleaning is regular cleaning which is carried out on a scheduled basis, not on an ad hoc basis and not in response to an outbreak

Question 25

What are the common issues with surface cleaning

Answer 25

Visual assessment of cleanliness = poor measure of invisible soiling ​ Visual clean can = large numbers of bugs and residues Body fluids form films which then makes it easier for bugs to attach themselves to. This then makes surface cleaning more difficult.  

Question 26

What is detergent

Answer 26

Body fluids form films which then makes it easier for bugs to attach themselves to. This then makes surface cleaning more difficult.  

Question 27

What is the difference between high and low level disinfectant

Answer 27

High level disinfectant -Kills all microbes (including mycobacteria) but not large numbers of bacterial spores ​ -Usually require longer contact time (hours)​ Low level disinfectant -Kill most vegetative bacteria, some fungi and some viruses in a practical period of time (<10 mins)

Question 28

What factors compromise the efficacy of detergents

Answer 28

Organic matter​ When dried or coagulated matter​ Time of exposure​ Coverage of large or irregular areas

Question 29

How can we break each linkin the chain of infection

Answer 29

Infectious Agent – ? ​ Reservoir – Surface design, Surface material, Cleaning, Role of detergents ​ Portal of exit – Aerosol control ​ Mode of Transmission – Hands, fomites (objects or materials) ​ Portal of entry – PPE ​ Susceptible Host – Vaccinations