Microbiology Chapter 23

Physical methods of controlling microorganisms are:

Scrubbing, heat, cold, and ultraviolet light.

Factors Influencing Chemical Agents

Several factors influence the effectiveness of antimicrobial agents: Nature of the disinfectant Concentration of the disinfectant Nature of the material to be disinfected Number of microorganisms present Type of microorganism present Length of exposure to disinfectant Temperature of the disinfectant during exposure Disinfectant's pH during exposure

Phenol

Slightly acidic, and is also known as carbolic acid.

Levels of control

Sterilization is the highest level of microbial growth(autoclave) because it is the process of completely removing or destroying all life forms, endospores, or their products on or in a substance. 2. Destruction offers less control of the growth of microorganisms. The process of disinfection does not inactivate microbial endospores. It kills most vegetative microorganisms. 3. Antisepsis are applied to living tissue.

There are 3 levels in controlling the growth of microorganisms:

Sterilization, Disinfection and Antisepsis

Light (ultraviolet)

Ultraviolet light is a form of nonionizing radiation thateffectively control the growth of microorganisms placed directly in its path . It inhibits microbial growth by damaging the cell's genetic material.

Iodophore

is a compound of iodine and a surfactant such as a dtergent than can slowly release the free iodine.

Cremation

Aform of incineration.

Sporicides

Agents that kill bacterial and mold spores, can also be used during the process of terminal disinfection of embalming instuments and equipment.

Autoclave

Apiece of equipment that works like a pressure cooker.

Joseph Lister

1827-1912 first used phenolic acid as a disinfectant during surgery to disinfect wounds.

Three methods of moist heat are?

Decontamination are boiling, free-flowing stream, and steam under pressure.

Chemical Methods of Controlling Microorganisms

Germicides, Bactericides, Fingicides, Vircides, Insecticides, Larvacides, and Sporicides. Germicides and Bactericides kill bacteria but not spores Fungicides kill both fungi and spores

Disinfectants suitable for mortuary procedures include:

Halogens, alcohols, aldehydes, phenolic compounds, and quaternary ammonium compounds.

Alcohols

Inclding ethyl alcohol, isopropyl alcohol, are used to control microbial growth. -alcohols are the most effective in aqueous solution because proteins are not soluble in high concentrations of alcohol. -alcohols are also added to other disinfectants to enhance their germicidal power.

Formalin

Is a concentrated liquid form of Formaldehyde used as a disinfectant in which gas is dissolved in water. Formalin 37% formaldehyde by mass 40% formaldehyde by volume.

Germicides

Kill a variety of different types of organisms but not necessarily spores.

Bactericides

Kill bacteria but not necessarily spores

Fungicides

Kills both fungi and their spores

Intesticides

Kills insects and larvacides kill larvae, which are worm like forms of newly hatched insects.

Static=

Prevent

Bleach + Formaldehyde =

Trihalomethane

Disadvantages of alcohol

alcohols are volatile , and they may evaporate before their germicidal effect occurs. -Isopropyl also lacks the ability to destroy hydrophilic viruses, and neither isopropyl or ethyl clcohol can be used to sterilize instruments because they do not kill bacterial endospores

Sea Level water boils

at 100 degrees Farenheit and 212 degrees Celcius and it takes about 10 mins to sterilize water that does not contain endospores.

One of the most important aspects of the embalming process is broken down into three 3 terms

Temporary Disinfection, preservation, and restoration of human remains.

Controlling the growth of microorganisms are reflected in the first two

Temporary disinfection and preservation.

Decimal Reduction Time

The time it takes to kill 90 percent of the present microorganisms.

What must embalmers do to stop the decomposrition of human remains?

They must retard the growth of microorganisms that coontribute to the decomposition.

Hydrophilic

Tough protein coat on virus making it hard to permeate. -Premeate= pass through

Boiling kills?

Vegetative bacteria, most viruses, and fungi.

Aldehydes

A group of organic compounds that control microbial growth by reacting with proteins in microorganisms and altering their chemical structure.

Scrubbing

A manuel process by which microorganisms are removed from a surface.

Tincture

A solution of iodine and alcohol that is primarily used as an antiseptic. -does not assure sterilization because it does not kill endospores.

Heat

Can be used to control the growth of microorganisms by incineration, dry heat, and moist heat. Which are forms of boiling, free-flowing steam, and steam under pressure , respectively.

Phenolic Compounds

Carbolic Acid, Cresols (Lysols), and Hexachlorophene

Cold Temperatures

Do inhibit the growth of microorganisms, which can begin multiplyng again when they are introduced to warm temperatures.

4 remaining Halogens

Fluorine, chlorine, bromine, and iodine. -each requires one electron to reach stability -both chlorine and iodine are used extensively as disinfectants.

Free-Flowing Stream

Fractional sterilization, items are placed in free-flowing stream for 30 minutes on successive days.

Glutaraldhyde

Inactivates the DNA and RNA of microorganisms.

Glutaraldhyde

Is an effective disinfectant and is actually a cold chemical sterilant when activated in a 2% solution. -germicidal in 10 minutes and kills endospores in3 - 12hours .

Temperature

Is another physical method in which the growth of microorganisms can be controlled.

Dry Heat

Is less effective than moist heat because proteins do not denature as easily when they are dry.

Disinfection

Is the destructuion of pathogenic agents by chemical or physical means by applying the disinfectant to an inanimate object.

Thermal Death Point

Is the lowest temperature which all microorganismsare killed in 10 minutes

Thermal Death Time

Is the minimum time it takes to kill all microorganisms present

Steam under pressure

Is the most effective form of controlling microbial growth because pressure, temperature, and length of exposure can be controlled.

Antisepsis

Is the process by which microbial growth is inhibited on living tissue to prevent infection.

Refrigeration

Is used at morgues to cool human remains and retard microbial growth.

Cides=

Kill

Vircides

Kill viruses

Sterilization

Offers the highest level of microbial growth control.

Iodine

controls microbial growth by oxidizing. -can be used in a form of a tincture or an iodophore.

The requirement to kill bacterial endospores?

15 pounds per square inch, at 121 degrees Celcius, for 15 minutes.

Combustion Chamber

Also known as a retort with a temperature of 1600 degrees Farenheit and 871 degrees Celcius

Halogens

Are widely used disinfectants that work by oxidizing the components of microbial cells. -Some halogens also react with cellular proteins. -6 elements on periodic table, found in the next to last cloumn on far right side.

Incineration

Burn to ashes... Often used in funeral homes

How does heat kill microorganisms?

By coagulating the proteins they contain and breaking hydrogen bonds within the microorganisms.

Larvacides

Kills larvae, worm like forms of newly hatched insects

A common iodophore :

Providone-iodine, or Betadine, which is a common antiseptic.