Ex. 15: disinfectants and antiseptic

Use-dilution method:

-The Use Dilution Test is a standard method for evaluating liquid and dilutable liquid disinfectants for hard surfaces. *can compare diff chemicals at diff time points* -this method is specified by the U.S. EPA as the required method for disinfectant claim substantiation. STEPS: -is performed, in brief, by soaking stainless steel carriers or small glass rods/beads in bacteria and then dried for 30 minutes. -In our lab, we use two kinds of bacteria: a gram-positive spore former, Bacillus megaterium, and a gram-positive non-spore-former, Staphylococcus aureus. -These bacteria carriers are then exposed to the test disinfectant at room temperature for 1, 5, 15, and 30 minutes. We use three disinfectants: Bleach, Lysol, and Windex. -Finally, after rinsing bacteria carriers with sterile water the glass beads are placed in nutrient broth to determine if any still have surviving bacteria. This makes the method a qualitative one, meaning that results are determined by whether or not bacteria grow, rather than by enumerating the bacteria.

Filter Paper Disk method:

-looking for the zone of inhibition. Which indicated the chemical will inhibit the growth of the microbe. STEPS: -The disk-diffusion method involves applying different chemicals to separate, sterile filter paper disks. -in our lab we use six different antiseptics: Mouthwash, Benzalkonium chloride, Povidone Iodine Solution, 1:1 Dilution of Soap in Water, 1:1 Dilution of Antibacterial Soap in Water. -A small disc of sterile filter paper is dipped into an antiseptic and then placed on an agar plate inoculated with a lawn of bacterial culture allowing the antiseptic to diffuse out into the agar. -The plate is then incubated to allow bacterial growth. After incubation, plates are examined for bacterial growth in the area where the antiseptic has diffused into the agar around the discs. - If the antiseptic is inhibitory, the bacteria will not grow where the antiseptic has diffused into the agar, and there will be a circular area absent of bacteria growth surrounding the disc. This area is called a zone of inhibition.

Compare and contrast antiseptics to disinfectants. Be able to name some examples of each.

-they are both widely used for cleaning in both homes and healthcare settings. -both used for destroying disease causing microorganism which may lead people to think they are the same -Disinfectants--> are chemicals that a can be applied to non-living objects or surfaces to inhibit the growth of microorganisms. FYI may not necessarily eliminate all the microorganism. -they prevent the spreading of germs and bacteria to people by sterilizing the surfaces where they are applied. -largely used in homes for cleaning bathrooms, kitchens and floors -ex: hydrogen peroxide (H2) is used in healthcare and hospitals to clean surgery tools and rooms. -ex of most common disinfectants: alcohols, oxidizing agents and bleaches. -some microorganisms may be resistant to some disinfectant becoming difficult to kill them completely. -Antiseptics--> are chemicals agents used to destroy or prevent the growth of microorganism that could cause infections or disease. -they are applied on broken skin to kill disease causing microorganisms that might have infected the areas or keep them away from these areas. -are meant to be applied on living tissue with zero injurious effects on the body surface where it is applied. -may act as sanitizers for cleaning hands to remove bacteria when a person cannot wash hands. -product examples: mouthwash, cold sores, treatment creams. -MAJOR DIFF 1. Disinfectants are applied to non-living items while antiseptics are applied to living tissue 2. disinfectants inhibit the growth of microorganisms that exist on surfaces that they are applied on while antiseptics kill and destroy microorganisms on living tissues 3. disinfectants disinfect areas that can spread germs while antiseptics reduce the risk of infections by germs. 4. disinfectants are very toxic and injurious when used on living tissues while antiseptics have no injurious effect on living tissue

zone of inhibition

If the antiseptic is inhibitory, the bacteria will not grow where the antiseptic has diffused into the agar, and there will be a circular area absent of bacteria growth surrounding the disc. This area is called a zone of inhibition.

Disinfectant

The elimination of microorganism from inanimate objects or surfaces. an agent used to disinfect inanimate objects or surfaces but is generally too toxic to use on human tissues. *The chemical agents designed to inactivate or destroy microorganism on inert surfaces*

Sanitizer

a chemical agent that reduces, but may not eliminate, microbial numbers to a safe level. They are intended to kill a predetermined number of vegetative cells (not endospores) on an already well-cleaned surface

Antiseptic

an agent that kills or inhibits the growth of microbes but is safe to use on human tissue. chemicals able to inhibit infection on/in a living organism. They do not need to kill the infection-producing agent, merely inhibit its growth. *an antimicrobial substance that are applied to living tissue/skin to reduce the possibility of infection, sepsis or putrefaction*

Denaturation

causes the tertiary structure of the protein to unfold so that some of its original properties, especially its biological activity, are eliminated *a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure, and secondary structure which is present in their native state. *

sterilization

the destruction of all life forms. *any process that removes, kill or deactivates all forms of life and other biological agents like prions present in a specific surface, object or fluid. *

Decontamination

the treatment of an object or inanimate surface to make it safe to handle. *the process of cleansing an object or substance to remove contaminants such as microorganism or hazardous material, including chemicals, radioactives. *

The standard method we could use to compare disinfectants is called the _______ method.

use- dilution