Lecture 2: Disinfection and Sterilization

Question 1

Define antiseptic

Answer 1

substance that prevents or arrest growth of microorganisms, substance applied to living tissues

Question 2

define asepsis

Answer 2

prevention of contact with microorganisms

Question 3

define autoclave

Answer 3

device that sterilizes instruments or other objects using steam under pressure

Question 4

define disinfectant

Answer 4

chemical or physical agent that destroys microorganism, substance applied to inanimate objects

Question 5

define nosocomial infection

Answer 5

infection acquired in hospital by patient who was administer for a reason other than that infection. Infection was not present or incubating at time of admission

Question 6

define sanitizer

Answer 6

agent that reduces the number of bacterial contaminants to safe levels as judged by public health requirements

Question 7

define sterile

Answer 7

state of being free from all living microorganisms

Question 8

define sterilization

Answer 8

process used to render a produce free of all forms of viable microorganisms

Question 9

what is a low level disinfectant used for

Answer 9

vegetative bacteria, fungi, influenza viruses

Question 10

what is an intermediate disinfectant used for

Answer 10

enteroviruses, mycobacterium tuberculosis

Question 11

what is a high level disinfectant used for

Answer 11

bacterial and fungal spores

Question 12

what are the types of physical and chemical sterilization

Answer 12

1. Physical: heat, filtration, radiation
2. Chemical: ethylene oxide, hydrogen peroxide

Question 13

what is the MOA of steam sterilization

Answer 13

destroys microorganisms by the irreversible coagulation and denaturation of enzymes and proteins

Question 14

what are the 4 parameters needed for steam sterilization of instruments and packs

Answer 14

1. Steam
2. Pressure
3. Temperature
4. Time

Question 15

what is the ideal steam for sterilization

Answer 15

dry saturated steam

Question 16

how does high pressure help with steam sterilization

Answer 16

helps attain higher temperatures

Question 17

what are ideal temperatures for steam sterilization

Answer 17

121 C (250 F) and 132 C (270 F)

Question 18

what are the time periods needed for steam sterilization at both temperatures

Answer 18

1. 30 minutes at 121 C (250 F) in gravity displacement sterilizer
2. 4 minutes at 132 C (270 F) in pre vacuum sterilizer

Question 19

mechanical indicators of sterilization won’t detect __

Answer 19

loading problems

Question 20

what are the chemical sterilization monitors/indicators

Answer 20

temperature sensitive tape, steam markers

Question 21

what is an example of a biological sterilization monitor/indicator

Answer 21

geobacillus stearothermophilus spores (heat resistant), dead spores= all microorganisms exposed will be dead

Question 22

what is flash sterilization

Answer 22

sterilization of an unwrapped object at 132 C (270F) for 3 minutes at 27-28lbs of pressure in a gravity displacement sterilizer

Question 23

when do you use flash sterilization

Answer 23

emergences- insufficient time to sterilize by other methods

Question 24

what is the most commonly used process for sterilizing temperature and moisture sensitive devices

Answer 24

ethylene oxide

Question 25

what is the MOA of ethylene oxide chemical sterilization

Answer 25

alkylation of a protein, DNA, and RNA which prevents normal cel metabolism and replication. Kills bacteria, spores, fungi and live viruses

Question 26

what are the disadvantages of ethylene oxide chemical sterilization

Answer 26

1. Lengthy cycle time -12hrs 2. Flammable and explosive 3. Toxicity

Question 27

what are the 5 stages of ethylene oxide cycle

Answer 27

1. Purging/humidificaiton 2. Gas introduction 3. Exposure at least 12hrs 4. Evacuation 5. Air washes- 12-24hrs

Question 28

what is the MOA of vaporized hydrogen peroxide chemical sterilization

Answer 28

generation of destructive free radicals that react with and kill microorganisms

Question 29

what are the advantages of vaporized hydrogen peroxide vs ethylene oxide

Answer 29

1. Less toxic 2. Shorter cycles

Question 30

what is MOA of ionizing radiation sterilization

Answer 30

damages DNA or microorganisms

Question 31

what is ionizing radiation used for

Answer 31

all prepackaged equipment

Question 32

what is cold sterilization used for

Answer 32

1. Soaking instruments in disinfectant solution- commonly dental supplies and minor surgery equipment 2. Surgical equipment- lenses instruments, metals, rubber, plastic