Sterilization And Disinfection

Question 1

what is disinfection

Answer 1

reduction in the number of microbes present

Question 2

What is required before disinfection

Answer 2

decontamination/sanitizing

Question 3

what is high level disinfection

Answer 3

destroys tough organisms (e.g., bacterial spores, tubercle bacilli, and viruses) given enough time

They are chemically sterilants

Question 4

What is sterilization

Answer 4

the elimination of all forms of life (except prions)

An absolute term cant be partially sterile

Question 5

what is decontamination used for

Answer 5

cleaning to remove debris, blood, proteinaceous material and other soiling

reduces organic material that might interfere with subsequent disinfections or sterilization

Question 6

What is microbial death rate

Answer 6

reduction in bacterial numbers is logarithmic and the proportion killed is constant for a particular set of conditions. until low numbers are left

Question 7

what do disinfectants target

Answer 7

protein denaturation or by membrane damage

Question 8

What part of the structure is loss by denaturation

Answer 8

secondary and tertiary structure leading to loss of function

Same sequence of aa but loses its structure which is irreversible (ex. egg analogy)

Question 9

What are the different methods of disinfection

Answer 9

1. Using Chemicals (antiseptics, or disinfectants)
2. Pasteratzation (adding moderate heat)
3. Preservation (drying, osmotic methods like adding sugar)

Question 10

For chemical disinfectant do we want a high or low concentration of the disinfectant, 70% vs 100% alc

Answer 10

Higher is not always better

ex. 70% alc is more affective than 100% alc
100% alc prevents the organisms from destroying itself and preserves it so it can layer regrow, at 70% alc it damages it so the organism cant regrow

Question 11

What are important factors that need to be considered for disinfectant activity

Answer 11

the concentration

the time of exposure (ex. takes time for something to actually be considered disinfected its not immediate)

the number and type of microbes present (the tougher the organism the longer it takes to destroy)

Nature of material (ex. we don’t want to disinfect electronics)

Question 12

What time of disinfectants target the cell membrane

Answer 12

detergents

Question 13

What time of disinfectants target proteins

Answer 13

alcohol

Question 14

What are the two types of chemical disinfectants and what are they used on

Answer 14

1. antiseptics - used on skin (ex. alcohol and iodine)
2. disinfectants - used on inanimate objects (may kill bacteria or prevent growth)

Question 15

when are low level disinfectants used

Answer 15

will kill vegetative (actively growing) bacteria, enveloped viruses and some fungi

used for routine cleaning and non critical equipment cleaning ( floor, wall, chairs)

Question 16

when are intermediate disinfectant used

Answer 16

will kill all bacterial pathogens expect spores, most fungi, and most viruses

used for areas of high risk of contamination or on equipment coming into contact with mucous membranes

Question 17

What is considered critical equipment and how is it cleaned

Answer 17

enters sterile tissues (vascular system)

Cleaning followed by sterilization

Question 18

What are examples of critical equipment

Answer 18

surgical instruments, biopsy instruments, foot care equipment

Question 19

What is considered semicritical equipment and how is it cleaned

Answer 19

equipment that comes in contact with nonintact skin or mucous membranes but not penetrate them

Cleaning followed by high level disinfection

Question 20

what are examples of semicritcal equipment

Answer 20

respiratory therapy equipment

anaesthesia equipment

Tonomoters

Question 21

What is considered noncritical equipment

Answer 21

equipment that touches sonly intact skin and not mucous membranes or does not directly touch the patient

Cleaning followed by ;ow-level disinfection

Question 22

What are examples of noncritical equipment

Answer 22

ECG machines, oximeters, bedpans, urinals and commodes

Question 23

does alcohol kill bacterial spores

Answer 23

no, handwashing is more effective

Question 24

what types of alcohol are used as a disinfectant

Answer 24

proposal usually bot also ethanol

Question 25

what is a phenol based disinfectant

Answer 25

its disrupts the cell membranes and precipitate proteins as it is chemically toxic it is chemically altered and phenolics are used

Question 26

what are oxidizing disinfectants and what is a common example

Answer 26

halogens (fluorine, chlorine, iodine) act by oxidation of enzymes 5.25% hypochlorite, javex (bleach)

Question 27

what is 5.25% hypochlorite made of mainly

Answer 27

chlorine

Question 28

what happens after a preparation is opened

Answer 28

activity drops once its open

Question 29

when is 5.25% hypochlorite used

Answer 29

often used for handling blood spills Inactivated by organic material, dont dilute in blood spills

Question 30

what is the danger with chlorine

Answer 30

if it becomes acidified

Question 31

what happens if you wash metal

Answer 31

corrosion leading to oxidation

Question 32

when is hydrogen peroxide used

Answer 32

H2O2 is used as a chemical sterilants at 30% [ ], detergent properties/cleaning abilities in wipes of solution, used on cuts as a disinfectant at 0/5-0.6% [ ]

Question 33

what does H2O2 and acetic acid give

Answer 33

peracetic acid (powerful disinfectant)

Question 34

What does H2O2 and formic acid make

Answer 34

performed acid (powerful disinfectant)

Question 35

What are the benefits of acid and peroxides

Answer 35

powerful disinfectants that are highly reactive (intermediate to high level) they are not affected by protein or enzymes

Question 36

What is quaternary ammonium

Answer 36

a quat possibly disrupts membranes (they are low level disinfectants) wipes used for detergent/cleaning activity

Question 37

what is the purpose of heavy metals in disinfectants

Answer 37

copper, silver and lead can be incorporated into ointments, medical devices (e.g., uriniary catheters)

Question 38

What is UV disinfection

Answer 38

UV light (wavelength 254 nm) is used Used for water, wastewater, air and surface disinfectants, now used in terminal rooms at hospitals or in biological safety cabinets

Question 39

Can resistance develop with antiseptics

Answer 39

yes

Question 40

what are iodophors

Answer 40

used for skin disinfection, not as severe as iodine

Question 41

what are chlorhexidine

Answer 41

used for skin disinfection and hand washing

Question 42

what is triclosan

Answer 42

used for hand washing often in soap

Question 43

what is transient flora

Answer 43

are organisms that are acquired on hands during routine work it can include resistant organs carried by patients and transmitters easily to. others

Question 44

what is called if a healthy person carries transient flora

Answer 44

carriage it can be eliminated by hand disinfection

Question 45

what is the single most effective infection control practice

Answer 45

hand antisepsis and alcohol properly used kills 99.9% of bacteria

Question 46

what is best to use of hands are soiled

Answer 46

hand washing

Question 47

what is autoclaving

Answer 47

moist heat (steam) at increased pressure for a defined time, used for surgical instruments, can kill bacterial spores

Question 47

what is autoclaving

Answer 47

moist heat (steam) at increased pressure for a defined time, used for surgical instruments, can kill bacterial spores

Question 48

who invented the autoclave

Answer 48

chamberland

Question 49

What level of reprocessing is required for an instrument that comes in contact with intact skin?

Answer 49

Cleaning and low level disinfection

Question 50

Which of the following statements is true of household bleach when used a s a disinfectant?

Answer 50

it may be inactivated by blood

Question 51

Which of the following is true of UV disinfection when used as 254nm wavelength?

Answer 51

It is used for rooms after their occupation is finished

Question 52

You have been given a solid metal device to sterilize. What method would most commonly be used for this purpose in hospitals in Canada?

Answer 52

Autoclaving, level 3 lab

Question 53

Which of the following classes of chemical would you use as an antiseptic?

Answer 53

alcohol

Question 54

is moist heat or dry heat quicker

Answer 54

moist (autoclave) 121 degrees C for 15 mins dry (oven) 350 F for 1 hour (less effective)

Question 55

when are gas and liquid used for sterilization

Answer 55

when things can't withstand high temps ethylene oxide, aldehydes, ozone, per acetic acid, h2o2

Question 56

when is irradiation used for sterilization

Answer 56

used on instruments, industrial process

Question 57

when is filtration used for sterilization

Answer 57

in pharmacies does not eliminate viruses

Question 58

how do you get an autoclave to work quicker

Answer 58

heating up to 340 degrees C 15 mins --> 2 mins

Question 59

How does an autoclave work

Answer 59

steam flows into the chamber steam replaces the air the material is exposed to the steam and its under pressure kills bacteria after 15 mins

Question 60

when is gas sterilization used

Answer 60

used for objects damaged by heat or radiation requires aeration step after sterilization

Question 61

what are examples of gas sterilants

Answer 61

ethylene oxide, formaldehyde gas, hydrogen peroxide vapour cant be stopped with radiation

Question 62

what are examples of chemical sterilants

Answer 62

practice acid and glutaraldehyde used in liquid phase

Question 63

solid --> liquid

Answer 63

melting

Question 64

liquid --> solid

Answer 64

freezing

Question 65

solid --> gas

Answer 65

sublimation

Question 66

gas --> solid

Answer 66

deposition

Question 67

liquid --> gas

Answer 67

vaporization

Question 68

gas --> liquid

Answer 68

condensation

Question 69

plasma --> gas

Answer 69

deionization

Question 70

gas --> plasma

Answer 70

ionization

Question 71

what does radiation use

Answer 71

microwaves or gamma radiation used in industry for plastic objects, fluids, etc

Question 72

what are prions cause by

Answer 72

caused of Creutzfeldt-jacob disease and "mad cow disease" by misfolding proteins, no nucleic acids

Question 73

where are prions found

Answer 73

neurological tissue (Brain)

Question 74

what is needed to be done with surgical instruments that have been infected with prions

Answer 74

discard them (ideal) soak in 1N NaOH + autoclave (alkaline conditions)