Sterilization and Disinfection

Question 1

What are approaches to control infectious disease agents?

Answer 1

1) the body’s own defense mechanisms - the field of immunology
2) chemotherapeutic agents - antibiotics and others
3) public health measures - national, state, local guidelines
4) sterilization and disinfection - control of infectious agents by physical and chemical means

Question 2

Sterilization

Answer 2

the destruction of all forms of life, including all bacterial spores; complete state/all or nothing

Question 3

What does - cide / -cidal mean?

Answer 3

to kill, make nonviable

Question 4

What does -stasis / -static mean?

Answer 4

to prevent multiplication without necessarily killing the agent

Question 5

Disinfection

Answer 5

a process that eliminates a defined scope of microorganisms, including some spores; used on inanimate objects

Question 6

Antiseptics

Answer 6

chemical agents applied to the skin to eliminate or reduce the number of bacteria present, spores are unaffected

Question 7

Sepsis

Answer 7

a toxic condition resulting from the presence of microbes or microbial products (toxins) in the body (NOT related to sterilization or disinfection

Question 8

Asepsis

Answer 8

a condition free of viable microorganisms

Question 9

Health-Care Associated Infections (HAIs) or Nosocomial Infections

Answer 9

infections acquired during a hospital stay or from other healthcare providers

Question 10

Surfactants

Answer 10

compounds that lower the surface tension between two liquids, a gas and a liquid, or between a solid and a liquid

Question 11

Detergent

Answer 11

a surfactant or mix of surfactants with cleansing properties while in dilue solutions

Question 12

Soap

Answer 12

a salt/fatty acid used for cleaning and lubricating; soaps are surfactants

Question 13

What is the primary purpose of soap?

Answer 13

to remove organic matter such as oils and dead skin cells that may harbor microorganisms

Question 14

Aseptic techniques - Surgical

Answer 14

practices that prevent microorganisms from gaining access to surgical wounds and tissues of patients

Question 15

How do we practice surgical asepsis?

Answer 15

hand washing with a surgical handrub technique using antiseptic and washed skin being kept wet with antiseptic for 3-5 minutes; cleaning and disinfecting or patient and surroundings before surgery

Question 16

Aseptic techniques - Medical

Answer 16

practices designed to keep objects, personnel, patients, and the hospital environment free from agents that cause disease

Question 17

What are examples of medical asepsis practices?

Answer 17

hand-washing, using gloves and gowns, incinerating body discharge, using sharp containers to dispose of syringes and needles

Question 18

Body substance precautions

Answer 18

a system of isolation in which barrier techniques are used for specific patient interactions vs specific diagnoses; standard of care for all patients; wearing gloves, gowns, face protection, and giving private room for patient as needed

Question 19

Special precautions

Answer 19

used in situations where patients have high-virulence airborne diseases such as TB

Question 20

Infection control committee

Answer 20

each hospital establishes their own, includes distinguishing nosocomial infections and identifying the source and methods of transmission of each infection

Question 21

Universal precautions

Answer 21

biosafety precautions in lab, assume all patients are infected with blood-borne pathogens, place specimens in a well constructed secure container with a lid, never pipette by mouth, always wash hands after completing lab activities

Question 22

How should healthcare professionals clean a bio-hazard spill?

Answer 22

1) contain the spill (ex. cover with absorbent material)
2) saturate towels with appropriate disinfectant solution (recommended 1:10 dilution of bleach, pour on outer edge of absorbent material and work towards center)
3) wait 10-15 minutes
4) discard everything into appropriate container (including your gloves)

Question 23

High-level disinfectant

Answer 23

uses a sterilant and kills everything but spores

Question 24

Intermediate-level disinfectant

Answer 24

uses an agent that kills viruses, fungi, mycobacteria, and vegetative bacteria but not spores

Question 25

Lowl-level disinfectant

Answer 25

uses an agent that kills vegetative forms of bacteria, some fungi, and lipid viruses

Question 26

Critical item

Answer 26

introduced into a normally sterile body area, require sterilization (ex. surgical intruments)

Question 27

Semi-critical items

Answer 27

touch intact mucous membranes; require high-level disinfectant agents (ex. endoscopes)

Question 28

Non-critical items

Answer 28

touch unbroken skin; require intermediate to low-level disinfection agents (ex. BP cuff, crutches)

Question 29

What factors influence the degree of killing?

Answer 29

type of bug, number of bigs, surface, contact time, temperature, pH, biofilms, concentration of disinfecting agent, presence of organic material (blood, sputum)

Question 30

What can interfere with disinfection/killing?

Answer 30

soil can provide protection for microorganisms, a more basic pH is harder to sterilize

Question 31

What problem can we encounter with bacterial endospores?

Answer 31

they are among the most resistant forms of life, they can survive intense temperatures; the genus Bacillus falls into this category

Question 32

What problem can we run into with Mycobacteria?

Answer 32

they are rather resistant to aqueous disinfectants because of their waxy cell surface

Question 33

What problem can we run into with blood-borne viruses?

Answer 33

they are problem agents because we can’t sterilize the bloodstream, meaning transmission is what we can prevent

Question 34

What issue can we run into with environmental organisms?

Answer 34

they can be found in many different locations and are often resistant to chemical disinfectants (ex. Pseudomonas aeruginosa and Acinetobacter)

Question 35

What heat methods we can use to achieve sterility and disinfection?

Answer 35

Moist heat, autoclave, dry heat, pasteurization, open flames/incinerators

Question 36

Moist heat

Answer 36

coagulation of proteins caused by breaking of hydrogen bonds can kill some microorganisms

Question 37

Autoclave (steam under pressure)

Answer 37

very effective, build 15 lbs of pressure to achieve 12 C for 15 or more minutes

Question 38

Dry heat

Answer 38

170 C for 2 hours, can be used on powder, oil and glassware

Question 39

Pasteurization

Answer 39

mild heating we use in food products to retain taste while sufficeintly killing microorganisms

Question 40

Open flame/incincerators

Answer 40

not very common, but used to be used for tweezers and inoculating loops

Question 41

What filter methods do we use to sterilize and disinfect?

Answer 41

membrane filters and high-efficiency particulate air filters (HEPA)

Question 42

Membrane filters

Answer 42

made of multiple materials, used to prepare media that cannot withstand autoclaving and solutions for patient use

Question 43

High-efficiency particulate air filters (HEPA)

Answer 43

used to filter air in operating suites and rooms of burn patients

Question 44

What radiation methods do we use to sterilize/disinfect?

Answer 44

Ionizing radiation and ultra-violet light

Question 45

Ionization radiation (gamma rays)

Answer 45

used for sterilization of plastics

Question 46

Ultra-violet light

Answer 46

can disinfect air, have very little penetration and can only kill microorganisms suspended in air or on surfaces

Question 47

What chemical methods do we use to sterilize/disinfect?

Answer 47

Chlorine, aldehydes, phenol, CHG, alcohols, iodine, heavy metals, oxidizing agents, QUATS, gaseous chemo sterilizers (very few achieve sterility, dilute according to manufacturer)