Types of Disinfecting agents Flashcards
What is most commonly used as part of an aseptic technique to disinfect surgical sites, injection sites, and sites with low-disinfectant requirements
Alcohols
What are the advantages of alcohol?
Low cost
General lack of toxicity when applied topically
Bactericidal activity against gram + and gram - bacteria
Produces the largest and fastest reduction in bacterial counts
What are the disadvantages of alcohol?
Ineffective against bacterial spores
Must be applied in sufficient quantities & remain in contact with the skin for 1 to 3 minutes to be effective
Flammable
What are the most common antiseptics applied to the skin?
Ethyl alcohol & isopropyl alcohol 70%
What has better virucidal activity?
Ethyl alcohol
What has better bactericidal activity?
Isopropyl activity
What is the mechanism of action of alcohol against pathogens?
Solubilizing lipid membranes and denaturing of proteins
What viruses are largely unaffected by alcohol disinfection?
Nonenveloped viruses like canine parvovirus
Why are high concentrations of alcohol less effective?
Very high alcohol concentrations lack the water needed to effectively denature the proteins of the pathogen
Does alcohol have any cleaning ability?
No. It should not be used to cleanse the site or equipment
What reduces the effectiveness of both ethyl and isopropyl alcohol?
The presence of organic debris
Why should alcohol not be used on open wounds?
It denatures the structure of serum exudate and allows for the formation of a barrier that may seal in underlying bacteria, allowing the infection to spread to underlying tissues
Why is alcohol not recommended for high-level disinfection?
It is not virucidal against naked viruses or bacterial spores
It is inactivated in the presence of organic debris
Why are Halogen Chlorine Compounds classified as intermediate-level disinfectants?
They can kill the vegetative forms of bacteria, algae, fungi, and both enveloped & nonenveloped viruses (parvovirus)
What is the mechanism of action of Chlorine compounds?
Denaturing protein structures
Chemically inactivating essential enzyme systems needed by the pathogen
In spite of a wider spectrum of activity what are many disinfectants not effective against?
Bacterial spores
What are chlorine disinfectants most commonly available as?
Sodium hypochlorite
What metal is chlorine not corrosive against?
High-quality stainless steel
What can generate when chlorine is mixed with other acidic cleansers?
Toxic amounts of chlorine gas
What can generate when chlorine is mixed with ammonia-containing household cleansers?
A very poisonous gas called chloramine
What is chlorine readily inactivated in the presence of?
Any organic material. It combines with organic material instead of the pathogen proteins
What are most Iodine Compounds and Iodophors used as?
Topical antiseptics before surgical procedures or for aseptic disinfection of tissue
Iodine Compounds and Iodophors are what?
Bactericidal, virucidal, fungicidal, and sporicidal
What is the mechanism of action of Iodine Compounds and Iodophors?
Diffuses into the pathogen cell and disrupts metabolism and protein structure and synthesis
Can iodine bring inactivated by organic material?
Yes, especially blood.
It is still considered to be better at maintaining its antiseptic activity in the presence of organic material than chlorines
What are Iodine Compounds and Iodophors quite effective against?
Dermatophytes that cause ringworms
What is used instead of free-iodine compounds?
Iodophors
Have a longer duration of antiseptic or disinfecting action
What is an iodophor?
A combination of molecular iodine and a carrier molecule that releases the iodine over time
Prolonging the antimicrobial activity
What is the most common iodophor?
Iodine mixed with polyvinylpyrrolidone (PVP)
A combination is more commonly known as Povidone-iodine
When are iodophors referred to as surgical scrubs?
When they are combined with detergent or nonionic surfactant
What are the surgical scrubs designed to do?
Clean dirty surgical sites by solubilizing dirt and organic material and providing some low-level disinfection
Why is it important to distinguish between iodophor solutions and scrubs?
The presence of the scrub soap is not appropriate for any use inside of the body
What cavity should neither iodine scrub nor solution never be used in?
Peritoneal cavity
What is a member of a class of antiseptics known as biguanides and is one of the most commonly used disinfectant and antiseptic compounds in veterinary medicine?
Chlorhexidine
What are the trade names of Chlorhexidine solution?
Nolvasan
Virosan
Hibistat
What is the wide range of Chlorhexidine related to?
Its low tissue irritation and its bactericidal and fungicidal properties
What is Chlorhexidine not considered effective against?
Nonenveloped viruses (parvovirus) and enveloped viruses
What is the mechanism of action of Chlorhexidine?
Damaging the cell membrane of the pathogen, lysing the cell
Is Chlorhexidine active against organic material?
Yes, including blood
Is combining chlorhexidine with other cleaning products advised?
No. It can be inactivated by anionic and nonionic detergents, soaps, and minerals in hard water
If Chlorhexidine is left in contact with the site, how long is its residual activity?
Up to 24 hours
Can chlorhexidine be considered safe as an external ear preparation?
Yes, but if the compound gains access to the middle ear it is considered to be ototoxic
What is a high-level disinfecting chemical sterilizer with a wide spectrum of activity against bacteria, viruses, fungi, and bacterial spores?
Glutaraldehyde
Glutaraldehyde has a similar chemical structure to what, but has less irritation and none of the potential carcinogenic effects?
Formaldehyde
Glutaraldehyde is used primarily for what?
A disinfectant on equipment that cannot be heat sterilized (endoscopes) and used to cold-sterilize clinical instruments
What is an advantage of glutaraldehyde?
It has the ability to kill bacteria normally protected from disinfectants by biofilm
Glutaraldehyde 2% are not inactivated by what?
Organic debris
Effective in the presence of hard water
What has a significant effect on glutaraldehydes?
Temperature
pH
How do oxidizing compounds work?
By denaturing proteins and lipids of microorganisms
What is commonly available as a 3% solution and has historically been used to debride necrotic tissue and kill bacteria?
Hydrogen peroxide
Is Hydrogen peroxide bactericidal or bacteriostatic?
Bactericidal
What version of hydrogen peroxide has been successfully marketed as a proprietary compound?
Accelerated hydrogen peroxide
What is the concentration of accelerated hydrogen peroxide?
0.5%
What does the manufacturer of accelerated hydrogen peroxide claim?
That it is bactericidal, virucidal, some fungicidal activity
What is another oxidizing agent that is used to disinfect pools, hot tubs and formulated with potassium to be used as a surface disinfectant?
Peroxymonosulfate
What is mixed with a surfactant, organic acids, and buffers in a dry powder to tablet form that has to be dissolved in water?
Potassium peroxymonosulfate marketed as Trifectant
Trifectant is what?
Virucidal (non-enveloped viruses), bactericidal, fungicidal
What is part of a larger group of related compounds in mouthwashes, surface disinfectants, and many household disinfectants (Lysol, pine oil, similar cleansers)
Phenols
What are phenol compounds quite effective against?
Gram + bacteria
What are phenol compounds quite ineffective against?
Gram-negative bacteria
Viruses
Fungi
Spores
Are phenols easily inactivated by organic material?
No
What are Quaternary Ammonium Compounds?
Cleansing agents with germicidal activity
What are quaternary ammonium compoinds used to disinfect?
surfaces of floors, walls, and vehicles used in livestock and egg-laying operations
Why are quaternary ammonium compoinds not used as antiseptics?
because the active ingredients bind to gauze & cotton
What is the major quaternary ammonium compound used in vet med?
Benzalkonium chloride which is the key ingredient in Roccal-D
What are quaternary ammonium compounds effective against?
Gram + bacteria
Enveloped viruses
What are quaternary ammonium compounds ineffective against?
Bacterial spores
Non-enveloped viruses
Poor efficacy against fungi & gram-negative bacteria
What is used together to irrigate ear infections, wounds, or fistulas with Pseudomonas and are considered effective against a fairly narrow spectrum of gram - bacteria and Staphylococcus aureus?
Ethylenediamine tetraacetic acid (EDTA) and Tris buffer compounded
