Microbiology: Exam 2

Iodophores [Mortuary Procedures] (Halogens)

- A compound consisting of iodine - Combines with a carrier, such as polyvinylpyrrolidone - Often used as a preoperative skin disinfectant (Betadine, Wescodyne); - Non-irritating, non-staining, some viruses, virtually odorless, kills bacteria, molds, and some viruses quickly [tincture of iodine is a solution of iodine and alcohol, used as antiseptic, and stain skin] - Acts by reacting with cellular proteins

Quaternary Ammonium Compounds

- Benzalkonium Chloride, Zephiran Chloride - Disinfectants and antiseptics that damage cell membranes and denature proteins - Surface active agents that alter the surface tension of cell membranes causing cell contents to leak out, destroying the cell - Deactivated in presence of soap, alkaline substances and other organic matter found in items such as gauze - Ineffective against spores, fungi and viruses - May only be bacteriostatic, skin and respiratory irritant - May cause birth defects in pregnant women - Neutralized in hard water - 1:1000 aq soin disinfect instruments, kill vegetative bacteria in 30 minutes (except TB)

Cresol [C6H5(OH)CH3] (Mortuary Procedures)

- Disinfectant - High level exposure result in irritation and burning of skin, eyes, and throat - Abdominal pain and vomiting, heart damage, anemia, liver and kidney damage, facial paralysis, coma and death - Commonly used because work well in the presence of other organic compounds, crude cresols form colloidal suspensions in water - Found in wood, tobacco, crude oil, and crosote - Not kill all spores - Not antiseptic because damaged skin is necessary

Alcohols (Halogens)

- Disinfectant that denatures cell proteins and dissolves lipids in the cell membrane - Most effective in 70% aqueous solution - May be added to other disinfectants to enhance germicidal power, mild antiseptics, and generally non-toxic to living tissues - Volatile (may evaporate before germicidal effect occurs) - Do not kill bacterial endospores - Inactivated by organic matter - Considered intermediate level disinfectants - Flammable A) Ethyl Alcohol (Drinking Alcohol) - (CH3CH2OH, grain alcohol) B) Isopropyl Alcohol [(CH3)2CHOH, rubbing alcohol] - do not destroy hydrophilic viruses

Boiling (Moist Heat)

- Disinfection process, not sterilization - At sea level water boils at 100*C - 10 minutes needed to kill vegetative bacteria, most viruses, and fungi - Higher elevations (lower pressure) - Lower boiling temperature (10,000 ft, 89.1*C)

Sedimentation

- Heavier particles settle to the bottom of the container and liquid can be decanted - Large particles and suspended bacteria sink to the bottom of lakes, ponds, and flowing streams

Incineration (Dry Heat)

- Organisms removed by burning - A form of sterilization because both vegetative bacteria and the endospores are inactivates - Drawbacks because the object is also destroyed and the waste matter must burn completely - Cremation is a form in incineration

Aldehydes (Halogens) [Mortuary Procedures]

- React with proteins in microorganisms and alter their chemical structure - Provides maximum cross-linking of proteins A) *Formalin* (Aqueous formaldehyde (HCHO) solution) - 37% by mass - 40% by volume - Irritant of the skin, eyes, nose and throat - Ingestion causes severe pain, vomiting, coma and death - Known human carcinogen - Strong reducing agent

Sanitation (Levels of Control)

- Reducing the number of pathogens to the point that they no longer present a serious health hazard - Which often happens with disinfection

Free Flowing Steam (Moist Heat)

- Steam not under pressure - Fractional sterilization is a 3 day process to kill both vegetative bacteria and endospores that germinate - 30 minute exposure time (disinfection technique)

Disinfection (Levels of Control)

- The destruction of disease-causing microorganisms. Generally, the disinfectant is applied to an inanimate object - Does not inactivate microbial endospores - It does kill most vegetative microorganisms

Antisepsis (Bacteriostasis) (Levels of Control)

- The prevention or inhibiting of the growth of causative (pathogenic) organisms. - Can be used on living tissue because not as harsh as disinfectants - Does not result in the immediate killing of the organism, it simply stops or greatly inhibits the growth of bacteria - Aseptic means absence of pathogenic microbes from an object or area - Preservatives are antiseptics added to prevent deterioration of foods, serums, vaccines and other biological products

Filtration

- The use of biological filters to mechanically remove bacteria from liquids - Used when the liquid cannot be heated to control the organisms - Pores of the filter are smaller than the bacteria

Fungicide (Disinfectant)

A substance that kills fungi and spores

Insecticide (Disinfectant)

A substance that kills insects (larvicide - kills insect larva)

The process of passing a liquid through a material with pores so small that bacteria cannot pass through is

Filtration

An agent that liberates gases for the purpose of destroying macroscopic life forms is a

Fumigant

What agent destroys yeasts and molds?

Fungicide

Dry Heat

Higher temperatures can be achieved than boiling or free-flowing stream (boiling)

The polyatomic ion of hypochlorite is composed of chlorine and

Oxygen

Which of the following is used as a standard to measure the efficiency of chemical disinfectants?

Phenol

Which of these chemical agents is described as a coal-tar derivative?

Phenol

Arsenic

Not allowed in mortuary

Physical / Mechanical (Methods of Control)

Remove microorganisms without necessarily killing or preventing their growth

Which mechanical method of sanitation is likely to be used in the practice or mortuary hygiene?

Scrubbing

For disinfection, alcohol is most effective in

Seventy percent solution

Which of the following is NOT an effective disinfectant?

Soap

Fumigation (Disinfection)

Spraying chemicals or vapors into the air to kill insects or small animals that carry microbial pathogens to humans (fumigant is the fumigation agent)

The most effective method of sterilization is

Steam Under Pressure

Which of the following is the killing of all forms of life?

Sterilization

Which of these processes will destroy bacteria at 121 degrees Celcius?

Stream under pressure

Why are ultraviolet rays lethal to bacteria?

They damage the DNA or RNA of the microbe

Which of the following is NOT a factor in the action of a chemical disinfectant?

Time of day

Which of these is a chemical agent capable of killing viral organisms?

Virucide

Phenolic Compounds [Mortuary Procedures]

- (coal tar detivatives) - Control microbial growth by denaturing proteins and disrupting cell membranes - Not effective in killing bacterial endospores - Provides moderate cross-linking of proteins A) Phenol (carbolic acid) [C6H5OH] - Sickeningly sweet and tarry odor - Flammable, skin exposure shown to cause chemical burns, liver damage, diarrhea, dark urine and hemolytic anemia - Breathed in when smoking tobacco - Due to toxic nature, phenolic derivatives have replaced phenol as disinfectant and antiseptic - Not greatly retarded by presence of organic matter

Hexachlorophene (Mortuary Procedures)

- 450 times more effective as germicide than phenol - Once used in soaps, deodorants, toothpaste, talcum powder, mouthwash and shaving cream - Now only available with a prescription, but is an ingredient in several commercial embalming chemicals - Used to treat acne

Sterilization (Levels of Control)

- A process of completely removing or destroying all life forms and/or their products on or in a substance. - Provides the highest level of microbial growth control - Most commonly used agent of sterilization is heat

Hypochlorites (Bleaches) [Mortuary Procedures]

- Containing compounds - Sodium hypochlorite (NaOCL): Liquid bleach, 5% solution - 1:10 dilution effective for disinfecting and cleaning - Irritating to skin and mucous membranes, corrosive, inactivated by the presence of organic matter - Lethal if combined with ammonia (NH3) or formaldehyde (HCHO) - Cl acts by oxidizing components of cells - Cl compounds are used to treat drinking H2O and maintain pools - Cl2 = kills and inhibits

Scrubbing

- Manual process by which microorganisms are removed from a surface - Should be vigorous and forceful on inanimate objects, but human remains should never be treated with great force due to the possible damage that can occur to the tissues of the body - May be facilitated by the use of soaps, detergents or disinfectants - Used in practice of mortuary hygiene - May include the use of towels, sponges, mops or other wetted devices - Soaps reduce surface tension to help spread over the surface rapidly and remain in thin film

Moist Heat

- More effective at denaturing proteins than dry heat because proteins denature more easily when wet - Lower temperatures and shorter exposure times - (121*C for 3 -- 1.5 hours)

Desirable Qualities Of An Ideal Disinfectant

1) Ability to attack most types of microorganisms 2) Rapid action 3) Low toxicity to body tissues 4) Effective in the presence of organic matter 5) Highly soluble in water - so can easily mix and clean up 6) Stability/shelf life - doesn't decompose when exposed to heat, light or adverse weather conditions 7) Harmless to fabric and metal 8) Easily available 9) High penetrating power - easily penetrates the material being disinfected 10) Inexpensive - Cost should be least important factors

Disinfectants Suitable For Mortuary Procedures

1) Halogens - Group 17 elements, strong oxidizers

Factors Influencing The Action of Disinfection

1) Type (nature) of disinfectant [s,l, or g] 2) Concentration of the disinfection (increase not always better) 3) Type (nature) of the material to be disinfected (porus or non-porus) 4) Microbial load / classification (number and kind of microorganisms present) (higher numbers take longer, vegetative or spores, mixed or pure) 5) Contact time of disinfectant (higher time, higher kill) 6) Temperature of disinfectant during exposure (Not always higher) 7) pH of disinfectant during exposure

Measure of Control

1. *Phenol Coefficient Test* - The standard by which all disinfectants are measured - Compare dilutions under STD conditions 2. If disinfectant is as effective as phenol, phenol coefficient is number 1 3. If disinfectant is more effective as phenol, phenol coefficient number is greater than 1 (a multiple of 1) 4. If disinfectant is less effective than phenol, phenol coefficient number is less than 1 (a fraction of 1)

Chemical

2 broad categories -cide = kill -static = inhibit growth

Disinfectant (Chemical)

A chemical or physical agent that kills disease-causing microorganisms

If a chemical is more effective than phenol, the coefficient is

A multiple of 1

Germicide (Disinfectant)

A substance that destroys microorganisms, not necessarily their spores

Virucide (Viricide) (Disinfectant)

An agent destructive to viruses

Bactericide (Disinfectant)

An agent that destroys bacteria but not necessarily their spores

Which of the following will inhibit bacterial growth and reproduction?

An antiseptic

Which of these agents will kill bacteria?

Bactericide

The condition in which bacteria are prevented from growing and reproducing is

Bacteriostasis

Which of these chemical agents is a member of the quaternary ammonium compound family?

Benzalkonium Chloride

Free-flowing steam is equal to

Boiling

Which of these is least effective in achieving a sterile environment?

Boiling

Which of these chemical agents is often referred to as phenol?

Carbolic acid

Which of these is primarily bacteriostatic in its action?

Cold

The killing or removal of all pathogenic microorganisms is

Disinfection

Which of the following is NOT a phenolic compound?

Glutaraldehyde

The most commonly used agent for the process of sterilization is

Heat

What process is used to destroy something of no value?

Incineration

Steam Under Pressure (Moist Heat)

- Autoclave (pressure cooker) - Higher pressure, higher temperature (15 psi, 121*C) shorter exposure time (15 minutes) - Sterilization process (getting rid of ALL microbes)

Hot Air (Dry Heat)

- Higher temperatures and higher exposure times needed when compared to moist heat - Care must be taken in that objects must be able to withstand the heat without charring or burning

Ultraviolet (UV) Light

- Inhibits growth by damaging genetic material - Organisms must be exposed directly - Paper can prevent UV light from penetrating enough to kill microorganisms - Can kill bacteria

Cold

- Inhibits growth, but does not kill all vegetative cells or endospores, therefore it is bacteriostatic

Heat (Sterilization)

- Kills microorganisms by denaturing the proteins they contain and proteins are denatures more easily when they are wet. - One of the most reliable means of controlling the presence of microorganisms of their growth - Denature means to cause the 3 degree structure of the protein to unfold so biologically activity is eliminated - Thermal death point - Thermal death time - Decimal reduction time (Kill 90%)