Micro Exam #3- Study Grind- Chapter 9

A chemical agent that only inhibits the growth is referred to as _______. What if it kills?

Bacteriostatic, bactericidal

Enzymes

Denature proteins, high against target substrate, remove prions on medical instruments ex. Human tears= lysozyme, which penetrates cell walls of bacteria causing it to rupture protects the eye

Oxidizing Agents

Denatures proteins by oxidation, release oxygen radicals, preventing metabolism High levels of activity Disinfectants, antiseptics for deep wounds, water purification, and sterilization of food-processing and medical equipment defends against anaerobic microorganisms ex. peroxides, ozone, and peracetic acid

True or False: boiling water cannot exceed boiling temperature

True, added heat is carried away by more escaping steam

Phenol

straight carbolic acid, denatures proteins and disrupts cell membranes original surgical antispeptic

Thermal Death Time

the time it takes to completely sterilize a particular volume of liquid at a set temperature

Surfactants

"surface active" chemicals, reduces the surface tension of solvents such as water by decreasing the attraction among other chemicals and disrupt cell membranes ex. Soaps and detergents, quats (ammonium cation)

What environmental conditions affect microbial death rates?

1) Temperature 2) pH 3) organic materials

What are the actions of antimicrobial agents?

1) altering cell walls and membranes 2) damage to proteins and nucleic acids

What are the factors affecting the efficacy of antimicrobial methods?

1) nature of site to be treated 2)Relative susceptibility of microorganisms 3) environmental conditions

Most resistant microbes

Bacterial endospores (bacillus and closteridium) Species of Mycobacterium (tuberculosis) Cysts of protozoa ***** Prions are the most resistant living thing

The time needed to reduce a population of bacteria by 90% (1 log drop in number) is the ________

D value rate of killing

How do phenols and phenolics kill bacteria (mode of action)?

Disrupt plasma membrane and denature proteins

Gaseous Agents

Ethylene Oxide, Propylene Oxide Denature proteins and DNA by cross-linking organic functional groups, thereby killing everything they contact without harming inanimate objects Sterilization of heat and water sensitive objects-- explosive and harmful to people High level of activity

What are the two types of pasteurization?

Flash pasteurization= 72 for 15 Batch Pasteurization= 63 for 30

Iodine (Halogen)

Halogen antiseptic, can treat water

Why is hot dry air a good sterilizing agent?

It denatures proteins and fosters the oxidization of metabolic and structural chemicals; requires longer times and higher temperatures because it penetrates the microbes more slowly

How does pasteurization work? Are all organisms eliminated?

Low heat denatures proteins and damages plasma membrane. No only some will be eliminated

Boiling is, dry heat or moist heat?

Moist heat

What are heat-related antimicrobial methods?

Moist heat Dry heat

What type of organisms or infectious agent is most difficult to kill by chemical means?

Prions are hardest, then endospores

If you want to kill a bacterial population in a shorter period of time what might you be able to change if you can't change the agent?

The concentration is usual. Temperature increase may help (a second agent)

Choose the agent that will kill the hardest agent there is to kill because then it will kill all that are easier as well. True or False?

True

Disinfectants are more concentrated and can be left on the surface for longer periods of time. True or False?

True

True or False: After freezing food some microbes can still be intact

True

True or False: Chemical agents tend to destory or inhibit the growth of enveloped viruses and vegetative cells of bacteria, fungi and protozoa more than fungal spores, protozoan cysts or bacterial endospores

True

True or False: Longer boiling time has great antimicrobial strength

True

True or False: Moist heat is better than dry heat because water is a better conductor of heat in the air

True

True or False: Slow freezing is more effective than fast freezing

True

True or False: Sterilization does not kill prions (infectious proteins)

True

True or False: alcohol-based antiseptics are more effective than soap in removing bacteria from hands but not effective against some viruses (diarrhea), swabbing skin with alcohol is a physical action

True

True or False: enveloped viruses are more easily disrupted than the protein coats of nonenveloped viruses

True

True or False: high temperatures denature (cell walls and nucleic acids) proteins

True

True or False: if cell membrane is disrupted by physical or chemical agents the cell is at risk of bursting as water moves into the cell by osmosis

True

True or False: sterilization in the autoclave requires the steam to be able to contact all liquids and surfaces that might be contaminated with microbes

True

True or false: true sterilization using heat requires higher temperatures than that of boiling water

True, increased pressure from not letting off steam

True or False: Pure alcohol is not a good disinfecting agent

True, water is needed to denature proteins

How does an autoclave work?

When steam enters the autoclave chamber, it forces air out, raises the temp of the contents, and increases the pressure until a set temperature and pressure are reached 121 degrees C 15lbs per sq in

bacteriostatic

a chemical or physical agent inhibits microbial metabolism and growth but doesn't necessarily kill the microbes

lyophilization

a technique of combining freezing and drying, to persevere microbes and cells for many years

bactericidal

agents that destroy or permanently inactivate a particular type of microbe

What do high level germicides kill?

all pathogens including bacterial endospores (used to sterilize invase instruments like implants)

aseptic

an enviorment or procedure that is free of contamination by pathogens

Antimicrobials

antibiotics, semi synthetics and synthetics Act against cell walls, cell membranes, protein synthesis and DNA transcription and replication Intermediate to low activity Used for disinfectants and treatment of infectious diseases

Heavy Metals

aresenic, zinc, mercury, silver, copper, etc Denature proteins, combine with sulfer atoms in cystiene Low level of activity Fungistats in paints; silver nitrate cream; surgical dressings, burn creams and catheters; copper in swimming pools and aquariums put on newborns eyes for blindness

Alcohols

bactericidal, fungicidal and viriusidical against enveloped viruses. Not effective against bacterial and fungal endospores, intermediate level disinfectants, denature proteins and disrupt cell membranes ex. isopropanol, ethanol alcohols dry up fast, may not be on microbes long enough to effect them

Phenolics

carbolic acid chemically altered, compounds derived from phenol molecules that have been chemically modified by the addition of halogens or organic functional groups, denatures proteins and disrupts cell membranes, intermediate to low activity level. Disinfectants and antiseptics ex. pine and clove oils. Chlorine mix, lysol

Chlorine (Halogen)

disinfects water

How do Quats function?

disrupt cellular membranes so that affected cells lose essential internal ions (k+) bactericidal

Desiccation

drying, used to preserve foods, inhibits microbial growth because metabolism requires liquid water inhibits spread of most pathogens except some mold on raisins

What do low-level germicides kill?

eliminate vegetative bacteria, fungi, protozoa and some viruses. Used to disinfect only what comes in contact with skin like furniture

True or False: disinfection does guarantee that all pathogens are eliminated

false

True or false: pasteurization is sterilization

false

Halogens

four very reactive, nonmetallic chemical elements: iodine, chlorine, bromine (hot tubs), and fluorine (toothpaste) intermediate level of activity effective against vegetative bacterial and fungal cells, fungal spores some bacterial endospores and protozoan cysts, and many viruses used alone and combined unfold and denature proteins and enzymes

What do intermediate level germicides kill?

fungal spores, protozoan cysts, viruses and pathogenic bacteria but not bacterial endospores. respiratory devices

Aldehydes

glutaraldehyde and formaldehyde (-CHO) Denature proteins High level of activity Used as disinfectant and embalming fluid

Pasteurization:

heating a product enough to destroy the microorganisms that cause spoilage without ruining the taste, also used to kill pathogens

Ultra high temperature sterilization

involves flash heating to get rid of all living microbes

Iodophor (Halogen)

iodine-containing organic compound that slowly releases iodine long lasting and not irritating on skin ex. Betadine prepares skins for surgery

How does lyophilization work?

microbes or object is subjected to dry ice and then subjected to a vaccum that removes frozen water through sublimination (water is transformed directly from solid to gas) this prevents formation of large dangling and damaging ice crystals

What is the different between disinfecting and sanitation?

one is in private place and one is in public area

Synthetic Detergents

positively charged organic surfactants that are more soluble in water than soaps

What is hot air sterilization used for?

powders and oils that are effected by water ex. coco powder

What does refrigeration do?

refrigeration decreases microbial metabolism, growth and reproduction because chemical reactions occur more slowly in low temperatures cold loving microbes (psychrophilic) still live in fridge, halts mesophiles, Listeria and Yersinia (blood products),

How does refrigeration work as a method to control bacterial growth?

slows metabolism and therefore slows growth

Tinctures

solutions of other antimicrobial chemicals in alcohol--> often more effective

What are ionizing radiation used for?

sterilizaiton of medical and lab equipment and preservation of food (destroys DNA)

what are nonionizing radiation used for?

sterilization and disinfection of surfaces and other transparent fluids and gases (Mutates DNA- thymine dimers)

autoclave

sterilize chemicals and objects that can tolerate moist heat. Consists of a pressure chamber, pipes to introduce and evacuate steam, valves to remove air and control pressure and gauges as well.

Nature of site being treated example

surgery sterilization of skin

What happens if there is damage to the envelope by physical or chemical agents?

the enveloped virus is not able to replicate

Thermal Death Point

the lowest temperature that kills all cells in a broth in 10 min

Filtration

the passage of a fluid (either a liquid or gas) through a sieve designed to trap particles (cell or virus) and separate them from fluid

microbial death

the permanent loss of reproductive ability under ideal environmental conditions

Sanitization

the process of disinfecting places and utensils use by the public to reduce the number of pathogenic microbes to meet accepted public health standards

What is degerming?

the removal of microbes from a surface by scrubbing (such as washing hands or prepping for an injection) action of scrubbing with soap or alcohol is more important in removing microbes

Sterilization

the removal or destruction of all microbes, including viruses and bacterial endospores, in or on an object

Pasteurization

the use of heat to kill pathogens and reduce the number of spoilage microorganisms in food and beverages ex. milk, fruit juice, wine and beer

What does boiling kill?

the vegetative cells of bacteria and fungi, the throphozoites of protozoa and most viruses within 10 min at sea level

Osmotic Pressure

use high concentrations of salt or sugar in foods to inhibit microbial growth ex. honey and pickles, fungi can deal with this

Disinfection

use physical or chemical agents known as disinfectants (ex. UV light, heat, alcohol and bleach) to destroy or inhibit microorganisms especially pathogens (not endospores or viruses)

Microbial Death Rate

used for evaluating the efficacy of an antimicrobial agent. constant time/ over number of living organisms under a particular set of conditions straight line= constant. Exact population killed each minute

What does moist heat do?

used to disinfect, sanitize, sterilize, pastuerize, kills cells by denaturing proteins and destroying cytoplasmic membranes

antisepsis

when a disinfectant chemical is used on skin or other tissue

Decimal Reduction Time (D)

when measuring the effectiveness of heat sterilization. the time required to destory 90% of the microbes in the sample

antiseptic

when the disinfectant chemical is used on skin or other tissue it is called an _______.