Disinfection and Sterilization

Question 1

List the bacteria/viruses from most resistant to least resistant (Spaulding’s Classification)

Answer 1

Prions
Endospores of bacteria
Mycobacteria
Cysts of protozoa
Vegetative protozoa
Gam-negative bacteria
Fungi, including most fungal spores
Viruses without envelopes
Gram-positive bacteria
Viruses with lipid evelopes

Question 1

Define the three types of equipment and give examples

Answer 1

Noncritical: either don’t touch patient or only touch intact skin
Semi-critical: contacts non intact skin or mucous membranes, but doesn’t penetrate them
Critical: Enter sterile tissue including blood vessels

Question 2

What does/doesn’t Low-Level Disinfection kill, and what type of equipment is it for?

Answer 2

It is for non-critical items.

It will kill most vegetative bacteria; some fungi. It will not kill mycobacteria, or spores

Question 3

What does/doesn’t High-Level Disinfection kill, and what type of equipment is it for?

Answer 3

It is for semi critical items. Must be capable of sterilization when contact time is extended.

It will kill/destroy vegetative bacteria; kill mycobacteria, fungi, both enveloped and non-enveloped viruses. Does not necessarily kill spores

Question 4

What items must be sterilized?

Answer 4

Items that are in contact with the blood stream; items contacting non-intact mucous membranes or normally sterile body sites; surgical instruments, needles, syringes, cardiac and urinary catheters, scopes, instruments for foot care

Question 5

List 7 factors that affect microbial growth

Answer 5

1- Nutrient availability
2- Moisture
3- Temperature
4- pH
5- Osmotic pressure
6- Barometric pressure
7- Gaseous atmosphere

Question 6

List 3 ways to control microbial growth in vitro

Answer 6

Cleaning, Disinfection (aseptic), and sterilization

Question 7

List cleaning equipment and * those that are most commonly used by RT’s.

Answer 7

Alcohol, Formaldehyde, Glutaldehyde, Hydrogen Peroxide, Iodine/Chlorohexidine, Peracetic Acid, Phenolic, Quaternary Ammonium, Bleach (Sodium Hypochlorite), White Vinegar (homecare)

Question 8

common examples of cleaning products

Answer 8

1. soap and water
2. detergents
3. 0.5% accelerated hydrogen peroxide

Question 9

common examples of low level disinfection

Answer 9

1. 3% hydrogen peroxide for 10 mins
2. 60-95% alcohol (10 mins)
3. 0.5% accelerated hydrogen peroxide

Question 10

common examples of high level disinfection products

Answer 10

1. 2% glutaraldyhyde (20 mins at 20 celcius)
2. 6% hydrogen peroxide (30 mins)
3. pasteurization (30 mins @ 75 celcius)
4. 7% accelerated hydrogen peroxide (20 mins)

Question 11

common examples of sterilization products

Answer 11

1. dry heat
2. 100% ethylene oxide
3. 2.5-3.5% glutaraldyhyde (10 hours @ 20 Celsius)