Sterilization, Disinfection, & Antisepsis- RA1 Flashcards Preview

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Flashcards in Sterilization, Disinfection, & Antisepsis- RA1 Deck (20):

Why are sterilization, disinfection, & antisepsis needed to prevent Hospital Acquired Infections (HAI)?

- Hospital acquired infections can lead to:
○ Serious illness or death
○ Extended stay & consequent loss of earnings/ hardship
○ Transmission of infection to other patients
- Studies indicate that 1/3 of hospital acquired infections are preventable

- Sterilization, disinfection & antisepsis are methods of preventing hospital acquired infections


Define sterilization.

Total destruction or physical removal of ALL microorganisms


List the most common methods of sterilization.

- Moist Heat
- Dry Heat
- Ethylene Oxide Gas
- Irradiation


Describe the mechanism of moist heat in sterilization.

Saturated steam under pressure (e.g. autoclave) kills microbes by irreversibly denaturing proteins, causing single strand DNA breaks & compromising membrane integrity


Describe the mechanism of dry heat.

Oven that kills microbes by irreversibly denaturing proteins, causing single strand DNA breaks & compromising membrane integrity


Describe the mechanism of ethylene oxide gas.

Kills by alkylating proteins, DNA, & RNA within cells, which prevents normal cellular metabolism & replication


Describe the mechanism of irradiation.

UV & Gamma Rays that kill by eliciting DNA damage through production of free radicals; blocking microbial replication


What is the definition of disinfection. How is disinfection different from sterilization?

- Disinfection= process of removing or killing most, but NOT all viable organisms
- Sterilization removes all organisms


What are the three categories of disinfection?

- High level
- Intermediate level
- Low level


What is the definition of high level disinfection?

High quality method that can approach sterilization; kills all but large bacterial spores--used for instruments & devices that cannot be sterilized


What is the definition of intermediate level disinfection?

Can kill most microorganisms but NOT effective against bacterial spores at all--used on semi-critical instruments that cannot be sterilized


What is the definition of low-level disinfection?

Kills most vegetative bacteria, some fungi, & some viruses-- used on non-critical instruments e.g. stethoscopes, BP cuffs...etc.


List the high level disinfection agents.

Peracetic acid
Hydrogen peroxide
Chloine compounds (bleach)


List the intermediate level disinfection agents.

Phenolic compounds


List the low level disinfection agents.

Quaternary ammonium


What is antisepsis?

Disinfectants are used to lower the number of microorganisms on skin surfaces
- None kill bacterial spores but do kill vegetative bacteria
- Are generally very safe


What is the most common & effective method for skin antisepsis for blood culture?

Iodine containing solutions


What are the two major iodine containing compounds?

1) Tincuture of iodine
2) Iodophors


Describe the mechanism of action of iodines.

Penetrates the cell wall of microorganisms & causes disruption of proteins, nucleic acid structure, & synthesis.


What are the two most highly resistant organisms to methods of disinfection & antisepsis?

1) Prions
2) Bacterial spores

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