Cleaning, Disinfection, and Decon and biocontainment

What does -cide mean?

Killing action

What does -static mean?

Growth inhibition/prevention

What is cleaning?

Removal of foreign material

What is sanitization?

Any cleansing technique that mechanically removes microbes

What is antiseptic?

Disinfectants applied directly to exposed body surfaces

What is disinfection?

Process to destroy vegetative pathogens on inanimate objects (not endospores)

What is sterilization?

A process that destroys all viable microbes including viruses and endospores. Microbiocidal

What is the rate of bacterial growth?

Exponential

What is the rate of bacterial death?

Constant

What are easily susceptible pathogens/

Enveloped virus, Gram positive and negative bacteria, large non-enveloped viruses, fungi

What are the hardest to destroy pathogens?

Prions, coccidia, bacterial spores, Mycobacterium, Protozoan cysts, non-enveloped viruses

What what does a higher number of microorganism mean?

Increases necessary contact time

How can the location of microorganisms impact disinfection and sterilization?

Pores can be hard to get through. Flat solid surfaces are easier

What disinfectant gets better the more it is diluted?

Iodophors because free iodine concentration is higher

What happens to the efficacy of most disinfectants as concentration increases?

It gets stronger

Increase in temp causes what for disinfection?

Improves it

T/F pH changes can improve or hinder an antimicrobial?

True

What is the most important factor to maintain efficacy of gaseous disinfectants?

Relative humidity

What can water hardness do to disinfection efficacy?

Divalent cations like Mg2+ or Ca2+ can cause insoluble precipitates with disinfectant

How can organic matter prevent disinfection or sterilzation?

They act as a physical carrier

Why feces in a footbath bad?

It becomes a physical barrier to the boot from disinfectant. This is why cleaning should be done before disinfection

What is filtration?

Passage of a liquid or gas through a filter with pores to retain microbes (common in vaccines or injectables)

What are the physical methods of microbial control?

Filtration

Osmotic pressure

Radiation

Desiccation

Temperature

What is osmotic pressure used to prevent bacterial growth?

High concentrations of salt and or sugar to create a hypertonic solution

What organisms have a greater availability than bacteria to survive hypertonic environments?

Fungi

What type of wavelength is better for penetration and has more energy?

Shorter

What are the ionizing radiation types?

Electron beams, gamma rays, x-rays

What is the nonionizing radation we use?

UV light

T/F UV lights are the only necessary disinfection in a BSC?

False, humidity can impact effectiveness, temperature is important, and dust can accumulate on the bulb

What is the human risk of UV light?

Causes pyrimidine dimers that can lead to eye, skin, or other melanomas

What is desiccation?

State of extreme dryness

What is lyophilization?

Freeze drying to preserve microbial cultures

What does desiccation and lyophilization do?

It creates a microbiostatic environment

What does high temperature do?

Denatures proteins

Interferes with cytoplasmic membrane and cell walls

Disrupts nucleic acids

What is thermal death point?

Lowest temp that kills all cells in 10 minutes

What is thermal death time?

Time to sterilize volume of liquid at set temp

T/F moist heat is more effective than dry heat?

True, water is a better conductor of heat than air

What are methods of using moist heat for disinfection, sanitation or sterilization?

Boiling, autoclaving, pasteurization, ultrahigh-temp sterilization

What does the pressure allow for in an autoclave?

Prevents team from escaping

When do you use dry heat over moist heat?

Moist heat will damage the item

What type of heat requires higher temperatures for a longer time?

True

What is the ultimate means of sterilization?

Incineration (dry heat)

What is dry heat most effective against?

Enveloped viruses, vegetative cells of bacteria, fungi, protozoa

What are ideal traits for a disinfectant?

Broad spectrum, fast-acting, stable, water soluble, not effected by environment, non-corrosive, non-toxic, easy to use, odorless, cleaning, environmentally friendly, inexpensive

What are the steps of cleaning and disinfection?

1. Remove all grossly visible debris

2. Rinse thoroughly

3. Allow area to dry

4. Apply appropriate disinfectant

5. Allow for proper contact time

6. Rinse thoroughly

7. Allow area to dry

What is risk group 1?

Does not cause disease in healthy human adults

What is risk group 2?

Limited and treated disease of minimal community risk with usually fecal-oral spread

What is risk group 3?

Causes serious disease with limited treatments and moderate to high community risk, typically aerosol spread

What is risk group 4?

Life-threatening with no treatments and high community risk

What factors goes into your risk assessment?

Risk, likelihood, hazard severity

What happens at BSL1?

Low risk work with minimal design features, programs

Required basic training

What is BSL-2?

Moderate risk work with some safety features and equipment

Task-specific training

What is BSL-3?

High risk work with more features and safety equipment

Must demonstrate proficiency and there are required training programs

What is BSL-4?

Extreme work risk with extensive features, redundant safety equipment, extensive programs and extensive training and demonstrated proficiency

What are some engineering controls to prevent incidents?

Sealed concrete walls, directional airflow, biosafety cabinet use, , vacuum lines that are filtered, PPE

What are some administrative controls to prevent incidents?

SOP training, security background checks, risk assessments, minors are not allowed, PPE

What is an example of a primary barrier?

Tube of ebola

What is an example of a secondary barrier?

Ebola in a tube in a BSC

What does 0.3um mean in a HEPA filter?

It is the most penetrating size of a particle. Smaller and larger particles are collected with higher performance

What can HEPA not filter?

Gases and vapors

What does HEPA stand for?

High Efficiency Particulate Air filter

How do HEPA filters work?

Straining, inertia impaction, interception, and diffusion

When do HEPA filters need replacement?

When they are loaded to the extend that sufficient airflow can not be maintained

Must be decontaminated before removal in high BSLs

Where are HEPA filters typically located?

Just outside of the room you are filtering air for

What hood protects the inside from the outside (product)?

Laminar flow hoods

What hood protects you from the inside?

Chemical fume hood

What BSCs protect the environment and you while working?

Class 1

What BSCs protect you, the product, and the environment?

Class 2, 3, and isolators

What is required PPE based on?

Project risk assessment

T/F PPE can be reusable or single use?

True

When should you use two gloves?

Working with infectious agents that you do not what on your skin

What does ABSL mean?

Animal biosafety level

What are two major animal biocontainment challenges?

Necropsy and sample transport

What is the mechanism of action for oxidizing agents?

Forms hydroxyl radicals leading to DNA damage

Attacks membrane lipids

Addition of metal ions will increase efficacy

What are the pros and cons for

Pros: Hard water friendly, kills spores, (also viruses, fungi, anaerobes and gram+)

Cons: Mildly corrosive, respiratory irritant, short shelf life, can leave a residue

What is the practical usage for oxidizing agents?

Very good for room decontamination and foot baths and effective against bacteria, viruses, fungi, and spores