TOPIC 15: Chemical Agents (IN PROGRESS)

CURRENTLY IN PROGESS!!!

1. Surface Active Compounds (Surfactants)

2. Phenolics

3. Alcohols

4. Alkylating Agents

5. Halogen Compounds

6. Oxidizing Agents (Peroxygenes)

7. Acids

8. Heavy Metal Compounds

9. Bisbiguanide

10. Supercritical Fluids

10 Common Disinfectants & Antiseptics (Categories)

Interfere with cell membrane functions

Mechanism of Action: Surfactants

Cell membrane damage —> Leakage of cell contents —> Lysis

Mechanism of Action: Phenolics

Protein Coagulation —> Damaged Cell membrane —> Lysis

Mechanism of Action: Alcohols

DNA Damage —> preventing cells from dividing and replicating

Mechanism of Action: Alkylating Agents

Oxidation causing indiscriminate destruction of the cellular protein, nucleic acid, and cell membrane of microorganisms

Mechanism of Action: Halogen Compounds

Protein Denaturation

Mechanism of Action: Acids

Protein Denaturation —> Impairing cell function by destroying enzyme activity of bacteria

Mechanism of Action: Heavy Metal Compounds

Disruption of bacterial cell membrane —> Increasing permeability and resulting in cell lysis

Mechanism of Action: Bisbiguanide

Penetrates cells forming carbonic acid —> Lowering cell pH (makes cell more acidic)

Mechanism of Action: Supercritical Fluids

1. Soap

2. Detergents

3. Quaternary Ammonium Salts (QUATS)

Types of Surface Active Compounds (Surfactants)

1. Phenol (Carbolic Acid)

2. Cresol

3. Hexachlorophene

4. Triclosan

Types of Phenolics

1. Ethyl Alcohol

2. Isopropyl Alcohol

Types of Alcohols

1. Formaldehyde

2. Glutaraldehyde

3. Ethylene Oxide

Types of Alklyating Agents

1. Iodine

2. Chlorine

3. Fluorine

Types of Halogen Compounds

1. Hydrogen Peroxide (H2O2)

Types of Oxidizing Agents (peroxygenes)

1. Boric Acid

2. Benzoic Acid

3. Salicylic Acid

4. Whitfield’s Ointment

Types of Acids

1. Mercury

2. Silver

3. Copper

4. Nickel & Zinc

Types of Heavy Metal Compounds

1. Chlorohexidine

2. Alexidine

Types of Bisbiguanide

1. Super Critical Carbon Dioxide (scCO2)

Types of Supercritical Fluids

Surface Active Compounds (Surfactants)

Group of chemicals that lower the surface tension of water

False: Soap does not inhibit microbial growth therefore is not an antiseptic and/or disinfectant.

True or false: Soap is considered an antiseptic and disinfectant.

Mechanically carries away microorganisms

If soap is not considered an antiseptic or disinfectant why is it used?

Triclocarban or cloflucarban compounds (structurally related to triclosan)

What are some bacteriostatic agents contained in soap?

Soap can inactivate the germicide

After soap, why must you clean with 70% alcohol before using a germicide>

Detergent

Surfactants with strong cleansing activity and leaves behind no soapy deposits.

Fungi - Yes

Protozoans - Yes

Enveloped Viruses - Yes

Endospores - No

TB Bacilli - No

Non-Enveloped Viruses - No

Yes or No - Answer whether Quaternary Ammonium Salts (QUATS) are effective on the following microorganisms:

Fungi -

Protozoans -

Enveloped Viruses -

Endospores -

TB Bacilli -

Non-Enveloped Viruses -

Enveloped Virus

Virus with an extra lipid bilayer surrounding the capsid

Non-Enveloped Virus

Virus that is more virulent than its counterpart since it causes host cell lysis

30 mins; 1:1000 dilution

What is the time and ratio of dilution of QUATS needed to kill vegetative bacteria?

Benzalkonium Chloride (Zephiran Chloride)

What is an example of a QUAT found in skin antiseptics, oral rinses, mouthwashes?

Carbolic Acid

What is phenol also known as?

Joseph Lister; 1860s

Who used carbolic acid as a disinfectant for surgical wounds and what year?

Joseph Lawrence; 1879

Who developed Listerine, an alcohol-based oral antiseptic and what year?

throat lozenges

Phenol (Carbolic Acid) can be found in ___ ___.

It is corrosive, therefore a skin irritant

Why is carbolic acid no longer used as a surgical disinfetant?

0.1-1%

At what concentrations is Phenol (Carbolic Acid) bacteriostatic?

1-2%

At what concentrations is Phenol (Carbolic Acid) bactericidal?

5%; 48 hours

What is the percent solution of Phenol (Carbolic Acid) that kills anthrax spores? How long should it be applied to be effective?

Cresol

Phenolic used to disinfect inanimate objects

Cresol

Phenolic whose ingestion may cause local mucocutaneous damage and extensive systemic toxicosis, including damage to the following systems: CNS, hematologic, renal, CV, pulmonary.

Lysol; 1889

What is a combination of cresol and soap? What year was this invented?

1-3%

What percentage of the phenolic hexachlorophene is incorporated into soaps and detergents?

Phisohex

What is the hexachlorophene that is a topical cleansing detergent widely used for handwashing in hospital settings?

Gram (+) - Yes (inc those causing Staphylococcal & Streptococcal infections)

Gram (-) - No

Yes or No - Phisohex is effective against the following bacteria:

Gram (+) -

Gram (-) -

Leads to neurotoxicity

Hexachlorophene was formerly used to bathe infants but has been discontinued. Why?

Triclosan

Phenolic initially used in toothpastes and now commonly used in hand soaps, hand washes, and shampoos despite evidence that it poses environment and health risks.

Triclosan

Phenolic impregnated into cutting boards, knives, shower curtains, clothing, and concrete to make them antimicrobial.

Gram (+) - Yes

Gram (-) - Some (certain gram(-) bacteria and yeasts)

Yes, No,Some - Triclosan is effective against the following bacteria:

Gram (+) -

Gram (-) -

At least 2 minutes

What is the contact time required for Triclosan?

70%

What is the best concentration of alcohol?

60-90%

What is the effective range of alcohol?

Coagulates surface proteins of microorganisms too quickly, preventing deep penetration

Why is 100% alcohol not optimal?

Below 50%

What concentration of alcohol causes its bactericidal effect to drop significantly?

Bactericidal - Yes

Fungicidal - Yes

Virucidal - Some (ONLY enveloped viruses)

Sporicidal - NO (but may inhibit processes of spore relation and germination)

Yes, No, Some - Alcohol is:

Bactericidal -

Fungicidal -

Virucidal -

Sporicidal -

False (Alcohol will not work in the presence of visible dirt)

True or false: Alcohol will work in the presence of visible dirt.

Highly Volatile

What property of alcohol makes it only effective after immediate application?

37%

What is the concentration of formaldehyde to make formalin?

Formaldehyde

Alkylating agent that acts as a gaseous disinfectant and biocide.

Bacteria - Yes

Viruses - Yes

Fungi - Yes

Endospores - Yes

Yes or No - Formaldehyde is effective on the following:

Bacteria -

Viruses -

Fungi -

Endospores -

Can sterilize at low temperatures

Why does formaldehyde offer an alternative to heat sterilization?

Formaldehyde

Alkylating agents commonly used for the following:

• Storing tissue specimens

• Embalming fluid

• Inactivate infectious agents

1. Very irritating to living tissues

2. Carcinogenic

Why isn’t formaldehyde used as an antiseptic?

10x

How much more effective is glutaraldehyde compared to formaldehyde?

Bactericidal - Yes

Sporicidal - Yes

Yes or No - Glutaraldhyde is:

Bactericidal -

Sporicidal -

2%; Cidex

What is the solution glutaraldehyde is commonly used as and what is it called?

Irritates the skin

Why isn’t glutaraldehyde used as an antiseptic?

Ethylene Oxide

Alkylating agent used as gaseous sterilization for the following items:

• Items in plastic bags/packaged (inc catheters, plastic petri dishes)

• Heat-sensitive items

Carcinogenic and explosive

Why does using Ethylene Oxide requires proper handling and aeration?

Iodine

Halogen compound used as a topical tincture but may cause staining or skin irritation.

Iodophor

Compound of iodine complex with an organic molecule and increasing iodine stability and efficacy

Povidone Iodine

A common iodophore that includes a wetting agent that releases iodine relatively slowly.

Betadine

Brand of povidone iodine that is used as a hand scrub by medical personnel before surery and for topical antisepsis of a patient’s skin before incision.

Hypochlorous Acid

Chlorine gas mixed with water produces this strong antioxidant capable of entering cells easily

Chlorine

Halogen used in municipal drinking water and wastewater treatment plants, which produces an acid that produces the actual antimicrobial effect.

Sodium Hypochlorite (Clorox)

Has a 0.5-1% chlorine concentration and chemical component of common household bleach

0.5-1%

What is the chlorine concentration in sodium hypochlorite?

Fluorine

Halogen that has antimicrobial properties contributing to the prevention of dental cavities which is why it is used for the following purposes:

• Main active ingredient of toothpaste

• Added to tap water in communities

Chlorine & Phosphate

Fluorine enhances the uptake of what ions in tooth enamel promoting remineralization.

Bacteriostatic

Fluorine is bacteriostatic or bacteriocidal?

Interferes with their metabolism and reduces their production of the acids that contribute to tooth decay

How is fluorine bacteriostatic for plaque forming bacteria?

3%

What is the concentration of hydrogen peroxide used to disinfect surfaces?

Hydrogen Peroxide (H2O2)

Inexpensive skin antiseptic that breaks down into water and oxygen gas but may also cause damage to the skin and delay healing or lead to scarring

• Contact lens cleaner

• In gaseous form, used as a sterilant for rooms or equipment

What is hydrogen peroxide usually used for practically?

Gram (+) - Yes

Gram (-) - Yes (however, has slightly greater efficacy for gram (+) bacteria)

Fungi - Yes

Viruses - Yes

Endospores - Yes

Yes or No - Hydrogen Peroxide is effective for the following:

Gram (+) -

Gram (-) -

Fungi -

Viruses -

Endospores -

• Eye wash products

• Pesticides

What is boric acid usually used for?

0.02%

What is the concentration of boric acid in eye wash products?

Preservative in food (like fruit juices, jams, ice creams, pastries, soft drinks, chewing gum, pickles)

What is the main purpose of benzoic acid?

Inhibitory effects on the proliferation of bacteria and yeasts

Why is benzoic acid typically used to avoid food spoilage?

Cosmetics and skin care products

Aside from being used in food products, what is benzoic acid also typically used in?

Skin disorders like acne, dandruff, psoriasis, seborrheic dermatitis of skin and scalp, common warts, and other skin conditions

What is salicylic acid usually used to treat?

6% benzoic acid and 3% salicylic acid

What is Whitfield’s Ointments are mixture of?

Superficial fungal skin conditions (like ringworms, athlete’s foot among others)

What is Whitfield’s Ointment usually used as treatment for?

Mild antibacterial activity

What type of activity does Whitfield’s Ointment have>

Heavy Metal Compounds

Very small concentrations of this type of disinfectant shows significant antimicrobial activity?

May bioaccumulate in human and animal cells in excessive concentration and can be toxic.

What is the problem of heavy metal compounds?

Bacteriostatic

Bacteriostatic or bacteriocidal: Mercury

Syphilis

What was mercury used for many centuries to treat?

Mercury

Heavy metal compound that is used less nowadays because of its toxicity to the body and environment including bioaccumulation ini fish

Merbromine (Mercurochrome)

Mercury

Topical antiseptic at 2% solution and has no effect on spores