STERILIZATION/DISINFECTION Flashcards by Klent Perez

Give me an example of a quaternary ammonium compound.`

Benzalkonium Chloride (Zephiran)

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Difference between boiling and pasteurization

Boiling destroys vegetative cells; pasteurization destroys food pathogen in milk and dairy products

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Biosafety Level 2 precautions

PPE, sterile technique, CP (contact precaution), vaccinations

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Which BSC?

Sterilize both the air entering and circulating the cabinet and exhaust air

CLASS II BSC

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Destruction of PATHOGENS is known as the process called what?

Disinfection

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True or False.

Alcohol is considered as an ANTISEPTIC.

True.

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What is the most common chemical sterilant?

Ethylene glycol

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Differentiate ionizing radiation from non-ionizing radiation.

Ionizing radiation - sterilization; short wavelength; high energy gamma rays
Non-ionizing radiation - disinfection; long wavelength; low energy UV light

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Which biosafety cabinet is open-fronted, with negative pressure and ventilated cabinets?

CLASS I BSC

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Which biosafety level?

Exotic viruses that pose life- threatening
risks; transmitted via aerosols with no
available vaccine or therapy

BIOSAFETY LEVEL 4

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What are the characteristics of the radiation used in ionizing radiation sterilization?

Short wavelength, high-energy gamma rays

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What is the standard temperature and time for autoclaving infectious wastes?

132°C, 30 to 60 minutes.

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Which biosafety level?

Airborne; viruses unlikely to be encountered in a routine lab

BIOSAFETY LEVEL 3

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Which BSC?

All air entering and leaving the cabinet is sterilized with HEPA filter

CLASS III BSC

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Autoclaving is used to sterilize what materials?

culture media and surgical instruments; possibly glassware too

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Expression of the bactericidal power of a particular substance as compared to pure phenol

Phenol Coefficient

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This Crede’s prophylaxis is used to prevent?

GON (gonococcal ophthalmia neonatorum)

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Iodine can come in three forms with regards to disinfection. What are those three?

Alcohol-iodine, iodophor, iodine tincture

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True or False.

Ethylene glycol and peracetic acid BOTH perform COLD sterilization.

True. <3

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What are the parameters for Tyndallization?

100°C for 30 minutes, for 3 consecutive days.

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What is the principle behind inspissation?

Thickening through evaporation

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Biosafety Level 3 precautions

PPE, sterile technique, aerosol precaution, vaccination

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What types of microorganisms are destroyed during sterilization?

Pathogenic and non-pathogenic microorganisms (vegetative cells and spores).

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Why is incineration banned in the Philippines?

Due to environmental concerns

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What does glutaraldehyde sterilize?

Medical instruments (e.g. bronchoscope)

Which BSC? Provide the highest level of safety

CLASS III BSC

What is the difference between an antiseptic and a disinfectant?

An antiseptic is used on living tissues, while a disinfectant is used on non-living things.

What types of materials are sterilized using filtration?

Culture media that cannot be heated, antibiotic solutions, CHO solutions, and vaccines.

What are the three main physical methods of sterilization?

Heat, ionizing radiation, and filtration

What is the temperature range and time for dry heat sterilization using an oven?

160 to 180°C for 1 1/2 to 2 hours.

What type of radiation is used in non-ionizing radiation disinfection?

Long wavelength, low energy UV light

Interpret a Phenol Coefficient (PC) value less than 1.

Phenol is more effective than the disinfectant.

What are the two methods in fractional sterilization?

Tyndallization and Inspissation

What is the standard disinfectant?

Phenol

Why are viruses sometimes able to pass through filters?

Because they are small (0.01 to 0.3 µm in diameter).

What are the four methods under dry heat sterilization?

Oven, Incineration, Flame, and Cremation

What disinfection method involves this to remain on skin for 60 seconds?

Iodine

Give an example of non-ionizing radiation.

Mercury lamps

This method of sterilization is used for culture media that CANNOT be heated.

Filtration

The two halogens that can disinfect are?

Iodine and chlorine

What is inspissation used for?

Sterilizing culture media with increased protein content, such as egg-based media and serum media

What are the two types of heat sterilization?

Moist heat and dry heat

What is the temperature range for incineration?

870 to 980°C

Biosafety Level 3 includes organisms such as?

MTB cultures, mold stages of systemic fungi

What is cremation used for in terms of sterilization?

Controlling diseases

Biosafety Level 1 precautions

PPE, sterile technique

Which method of sterilization is INACTIVATED by ORGANIC COMPOUNDS?

QUATS (Quaternary Ammonium Compounds)

How does air filtration work?

HEPA filter (High Efficiency Particulate Air filter)

What is incineration used for?

Sterilizing infectious wastes by reducing them to ashes

Iodine + detergent is?

Iodophor

Name the principle behind tyndallization.

Fractional Intermittent / Discontinuous Sterilization

Describe the process of fractional sterilization.

It involves heating to kill vegetative cells, an incubation period allowing spores to germinate, and then a final heating step to kill the germinated cells.

Which BSC? Unsterilized room air enters and circulates within the cabinet and exhaust air from cabinet is filtered by HEPA filter

CLASS I BSC

Disinfection is also divided into physical and chemical methods. Name all three physical disinfection methods.

Boiling, Pasteurization, and Non-ionizing radiation

What metal compound is found in Crede's Prophylaxis?

1% silver nitrate

What size particles does a HEPA filter remove?

Particles larger than 0.3 µm

Under moist heat, what are the two sterilization methods?

Autoclaving and fractional

What biological indicator is used to validate autoclave sterilization?

Bacillus stearothermophilus

What are the two main methods of pasteurization? Give their temperatures and times.

Batch/LTH: 63°C for 30 minutes; Flash/HTH: 72°C for 15 seconds.

What is the purpose of flaming in sterilization?

Sterilizing wire loops and inoculating needles

What biological indicator is used to validate dry heat sterilization in an oven?

Bacillus subtilis var. niger

What is formaldehyde vapor and vapor phase H₂O₂ used to sterilize?

HEPA filters in Biological Safety Cabinets (BSCs)

What does peracetic acid sterilize?`

Surfaces of surgical instruments

What equipment do you need to perform autoclaving?

Autoclave

The biologic indicator in ionizing radiation

Bacillus pumilis

Name the five chemical methods of disinfection.

Alcohol, Quaternary Ammonium Compounds (QUATS), Halogen, Heavy metal, and Phenol

Dry heat sterilization using a flame is aided by the use of what laboratory equipment?

Bunsen burner

Which biosafety level? Common clinical pathogens

BIOSAFETY LEVEL 2

Chlorine is found in which household item?

Bleach

Which biosafety level? No known potential for infecting healthy people

BIOSAFETY LEVEL 1

Differentiate incineration and cremation.

Incineration burns infectious wastes and animal carcasses; cremation burns human and animal remains.

Which organism does copper primarily target?

Algae; hence the term, algicide (killing algae)

Name two general methods of sterilization.

Physical methods and chemical methods

Tyndallization can sterilize what?

Heat-sensitive media

Biosafety Level 2 includes organisms such as?

B. anthracis and Y. pestis

Chlorine is most often used in the form of?

Sodium hypochlorite

True or False. Sterilization only targets harmful (pathogenic) microorganisms.

False. Sterilization targets all microbial life, both pathogenic and non-pathogenic.

What is the most effective method of sterilization?

Autoclaving

What organisms are typically used in the Phenol Coefficient test?

Salmonella typhi and Staphylococcus aureus

What is sterilization?

The complete destruction of microbial life, including both pathogenic and non-pathogenic organisms (vegetative cells and spores).

Biosafety Level 1 includes organisms such as?

B. subtilis and M. gordonae

What is the temperature and time required for boiling to effectively disinfect?

100°C for 15 minutes

What is the standard temperature, pressure, and time for autoclaving?

121°C, 15 psi, 15 minutes

What is the best concentration for an alcohol to be an effective antiseptic?

70% ethyl alcohol / isopropyl alcohol

Biosafety Level 4 precautions

Class III BSC, isolation, personnel and contaminated material must be decontaminated before leaving the facility

What are the parameters for inspissation?

75 to 80°C for 2 hours, for 3 consecutive days.

CLASS II BSC is also known as?

LAMINAR FLOW BSC

What disinfection method destroys food pathogen in milk and dairy products?

Pasteurization

What equipment is used for Tyndallization?

Arnold Sterilizer

Interpret a Phenol Coefficient (PC) value equal to 1.

The disinfectant and phenol have the same effectiveness.

What is the purpose of boiling as a disinfection method?

To destroy vegetative cells.

Name the disadvantages of QUATS.

nonsporicidal, nontuberculocidal

What heavy metal is the active ingredient in Merthiolate?

Mercury

Chlorine can be neutralized with?

Sodium thiosulfate

What is the quality control (QC) organism used for ethylene glycol sterilization?

Bacillus subtilis var. globigii

Iodine in alcohol is?

Iodine tincture

Which BSC? Used by most hospital microbiology laboratories

CLASS II BSC

Biosafety Level 4 includes organisms such as?

Arbovirus, Arenavirus, Filovirus

What type of materials are commonly sterilized using ionizing radiation?

Plastic syringes, catheters, and gloves

True or False. Pasteurization is a sterilization method.

False. It is a disinfection method.

What is an advantage of using glutaraldehyde for sterilization?

It does not corrode metal or rubber.

What is the principle behind autoclaving?

Steam under pressure

What is a general statement about the current recommendation for the use of heavy metals as disinfectants?

They are no longer recommended.

Which BSC? System is entirely close and all infectious material are handled with rubber gloves sealed to the cabinet

CLASS III BSC

How does liquid filtration work?

Pulling the solution through a cellulose acetate or cellulose nitrate medium using a vacuum.

Interpret a Phenol Coefficient (PC) value greater than 1.

The disinfectant is more effective than phenol.