Unit 8: sterilization, antiseptics and disinfectants Flashcards

Question

How is autoclave tape helpful

Answer 1

Placed on the outside of an autoclaved pack or container Tape changes colour as soon as it is exposed to 121*C Does not indicate how long it was exposed to that temp so it should not be sued as the only indicator of sterility

Answer 2

Strips of paper with a chemical pellet that melts after reaching a certain temp for a certain amount of time As the pellet melts, a dark dye wicks along the strip of paper. It must reach the end of the strip to be “accepted” Strips should be placed in the center of EACH individual pack and the center of the loaded autoclave to ensure sterility

Answer 3

A commercially prepared vial containing Bacillus stearothermophilus spores (which are killed at 121*C in 12 minutes) is paced in the center of an autoclave load. After autoclaving, contents of the vial are cultured at 56*C for up to 3 days to see if there is growth Used as quality assurance for the autoclave machine. Should be run periodically to ensure machine is working properly

Answer 4

Used when an item is required immediately Once the autoclave has reacher 120*C the load is timed for 3 min After that time, the autoclave is shut off, set on rapid exhaust and the drying cycle is skipped After sterilization, allow packs to cool slowly

Answer 5

Liquid sterilization - Glutaraldehyde Gas sterilization - Ethylene oxide - Plasma sterilization Aldehyde - Formaldehyde and glutaraldehyde - Toxic and irritating - Antimicrobial Cold sterilisation - Soaking instruments in disinfecting solutions (chlorhexidine or glutaraldehyde) - Used only for minor procedures or equipment that cannot tolerate other sterilization methods - Must be rinsed thoroughly with sterile water under aseptic conditions (sterile gloves)

Answer 6

Flammable, explosive, toxic Penetrates paper and plastic packaging without melting it - Wrapped in plastic packaging, sealed Temp versus time - 3-4 hours at room temp, humidity must also be controlled Quarantine is well ventilated area for a min of 24 h, time can be reduced to 4 h in an aerator

Answer 7

hydrogen peroxide Safer for enviro and personnel than ethylene oxide Not safe for - Linen - wood/paper - Endoscopes - Certain plastics - Liquids - This method cannot penetrate the walls of instruments so the lumen will remain contaminated

Answer 8

Antiseptics and disinfectants work by - Damaging the cell membrane - Interfering with or damaging proteins - Damaging DNA and/or RNA The strength of a disinfectant (how well it works) is measured by a value called the Phenol Coefficient or Co-efficent of disinfectant - The higher this number the better ability to kill microbes

Answer 9

Steal a piece of host cell membrane when they leave infected host cell – this envelope surrounds the virus particle If this envelope is disrupted, the virus is destroyed

Answer 10

Do not have any phospholipids (usually smaller pieces of genetic material in protein capsule) resistant to chemicals that damage cell membrane

Answer 11

Chemicals that work by destroying cell membranes are limited in their ability to kill spores and certain viruses Spores do not have cell Membranes Viruses can be broadly categorized as enveloped and non-enveloped viruses.

Answer 12

Has a good coefficient of disinfection Good killing action at low concentration Broad spectrum Vegetative bacteria and fungi; bacteria; endospores and fungal spores; enveloped and non enveloped viruses Stable Can be stored for long periods of time without losing effectiveness Can store at room temp, in the presence of light and air Homogeneous Uniform in composition; every application acts the same Soluble Soluble in water → makes it more effective to use (can spread, wipe, immerse) Non toxic to animals and people Non corrosive, non bleaching, non staining, not flammable Works at room temp High penetration of biofilms and fat Phenol very effective with fat;bleach is not Detergent ability Both cleans and disinfects; the ability to clean will help to penetrate fats, grime, biofilms Is not neutralized by organic material that may be present Ease of use Affordable and readily available Deoderizing

Answer 13

Most commonly used at 70% v/v dilution Kills all vegetative cells, including Mycobacterium Does not destroy spores, kills some (not all) viruses Dissolves lipids, dentures proteins, does not damage nucleic acids There must be contact time, so apply alcohol and allow to evaporate on own Has decreased efficacy at higher temp due to faster evaporation Ethanol is NOT effective at 95-100% due to rapid evaluation

Answer 14

Cuts through fat and lipids Inexpensive, readily available Can use on skin, on inanimate surfaces, for soaking → both a disinfectant and an antiseptic Comes in a hand gel format that includes surgical strength hand cleaners (must follow manufacturer's directions for surgical asepsis)

Answer 15

Will cause cooling when applied to skin Can be absorbed causing alcohol intoxication – especially in small animals and pediatrics Flammable, explosive Damages plastics and rubber

Answer 16

2-propanol Used at 70% v/v dilution (aka rubbing alcohol) As effective as ethanol, especially of fortified with iodine or another disinfectant Cheaper and more easily obtainable than ethanol

Answer 17

Commonly used disinfectants; contains ammonia Disrupts cell membranes and denatures protein

Answer 18

Broad spectrum against bacteria Effective at destroying enveloped viruses

Answer 19

Non enveloped virus Some Pseudomonas resistance Mycobacterium Spores

Answer 20

Stable, dissolves easily in water Odorless, does not stain, not corrosive Effective i n pus, blood, feces Inexpensive

Answer 21

Can cause slight injury to tissue Should never be mixed with soaps (will decrease efficacy) Decreased activity in hard water Older generations require long contact times (10-20 min)

Answer 22

Hydrogen peroxide (Peroxigard™) Hypochlorites Potassium peroxymonosulfate (Virokon®)

Answer 23

Very commonly used Hydrogen peroxide forms free-oxygen radicals These are very reactive oxygen molecules that can damage cell membranes, mitochondria and other cell components Activity Broad spectrum Non enveloped viruses Can destroy spores at very high concentration If concentration is too low, catalase producing bacteria may have some resistance

Answer 24

Decomposes to water and oxygen Inexpensive, easy to use aqueous solution Can be vaporized and used for “gas sterilization” Objects are placed in a chamber and gassed with a hydrogen peroxide compound Good for glass, metals, certain equipment

Answer 25

Decomposes in the presence of light, metals, oxygen New formulations are stable for months in storage

Answer 26

Chlorine containing agents Most common → sodium hypochlorite (bleach) Denatures protein The chlorine combines with water to release hypochlorous acid (HOCL) During reaction, any surrounding cysteine residues and S-S bonds are destroyed Broad spectrum including bacteria, fungi, spores and all types of viruses Acts within 30 min; spores may take hours

Answer 27

Concentrated solutions will rapidly release chlorine gas Never mix with acid → will produce toxic chlorine gas Never combine with Quats → will produce toxic chloramine gas Caustic effects to skin and mm, especially at higher concentrations

Answer 28

Concentrated sodium hypochlorite is 20% w/v Household bleach is 5.25% w/v sodium hypochlorite To use as a disinfectant, use a 10% solution of household bleach Corrosive → must be rinsed afterwards Be careful of fumes when using concentrated sodium hypochlorite Area must be well ventilated Avoid spills

Answer 29

Oxidizing agent with detergent action - Oxidizes sulfur bonds in proteins and enzymes disrupting the function of the cell membrane causing rupture of the cell wall Broad spectrum bacteria, fungi, most viruses (incl. parvo) - Not spores Comes as a tablet that makes a 1% solution in water - 7 day shelf life once made (must write date made) Requires 10 min of contact time followed by rinsing Disinfecting hard surfaces, including food bowls, cages, kennels Can also use as aerosol if concerned about air contamination Low toxicity but avoid direct skin use

Answer 30

Infrequently used in the vet clinic as they can cause toxicities in cats

Answer 31

Antiseptic that is related to the Quats Mild, low toxicity, rapid acting, poor absorption Complex organic molecules that dissociates into a positively charged salt This salt binds to and disrupts negative charges associated with bacteria cells walls Low concentrations: static High concentrations: cidal Broad spectrum against bacteria, yeast and some viruses No action on spores Antiseptic of choice for MRSA

Answer 32

Chlorhexidine are available in strengths ranging from 0.05% to 4% Higher concentration will cause tissue damage and delayed wound healing Intact skin with stand a higher concentration than wounds

Answer 33

Aqueous formulas - Do NOT have alcohol - Safe for use around eyes and for flushing of wounds Solutions continuing alcohol - NOT safe around the eyes and will cause damage to wound and healing tissue

Answer 34

Antiseptic Broad spectrum bactericidal (may be less effective than chlorhexidine – Jarral et al., 2011) Used at a 2-2.5% solution Can be purchased as A water (aqueous) solution A “tincture” 2.0-2.5% iodine in 70% ethanol More effective because can cut through lipid Used for cleaning cuts, wounds, surgical prep Apply a single coat to skin and allow to air dry AVOID eye contact Do NOT allow to pool under patient on a surgery mat Will cause burns if prolonged contact with solution

Answer 35

Iodine that is loosely bound to a detergent (such as povidone) that releases it slowly and cuts through organic matter Prolonged effect after applied to skin Not irritating to the skin; but can have mild hypersensitivity and will discolor skin Povidone-iodine is most common (betadine, Losan) Surgical scrubs (esp. In LA), teat dips