Ch. 11 – Microbiology – Flashcards

Unlock all answers in this set

Unlock answers
question
What is sterilization?
answer
The destruction of all microbial life.
question
What is disinfection?
answer
Destroys MOST microbial life, reducing contamination on inanimate surfaces.
question
What is antisepsis?
answer
Destroys MOST microbial life, reducing contamination on a living surface.
question
What is decontamination?
answer
The mechanical removal of most microbes from an animate or inanimate surface.
question
What are the primary targets of microbial control?
answer
the microorganisms that can cause infection or spoilage that are constantly present in the external environment.
question
What microorganisms have the highest resistance to forms of control?
answer
Prions and bacterial endospores.
question
What microorganisms have moderate resistance to forms of control?
answer
Protozoan cysts, some fungal spores, naked viruses, and some hearty bacteria like M.Tuberculosis, S.Aureus and Psuedomonas.
question
What microorganisms have the lowest resistance to forms of control?
answer
Most vegetative bacterial cells, most fungal spores/hyphae, enveloped viruses, yeasts and protozoan trophozoites.
question
What are the methods of microbial control?
answer
1.)Sterilization
2.)Disinfection
3.)Antisepsis
4.)Sanitization
5.)Degermination
question
What does sterilization do? What surfaces is it used on? What accompanies it?
answer
Removes all viable microorganisms including viruses and spores. Inanimate. Usually heat but chemicals can be used as well.
question
What does disinfection do? What surfaces is it used on? What accompanies it?
answer
The use of a physical process or chemical agent (disinfectant) to destroy vegetative pathogens and most viruses. DOES NOT DESTROY BACTERIAL ENDOSPORES AND SOME VIRUSES. Removes toxins. Used on inanimate surfaces.
question
What does Sanitization do?
answer
Any cleansing technique that mechanically removes microorganisms to reduce contamination to safe levels. Ex: washing dishes or clothes.
question
What is degermation? How does it work?
answer
Reduces the numbers of microbes on HUMAN SKIN. Works by removing oils and microbes on the outer layer of the skin through physical/chemical or both. Ex: hand washing and surgical scrubbing.
question
What does CIDE mean?
answer
To kill. DOES NOT NECESSARILY RESULT IN STERILIZATION.
question
What is a bactericide?
answer
chemical that destroys bacteria NOT endospores
question
What is a fungicide?
answer
Chemical that kills fungal spores, hyphae, and yeasts.
question
What is a virucide?
answer
A chemical that inactivates viruses.
question
What is a sporicide?
answer
Can destroy bacterial endospores.
question
What is a germicide/microbicide?
answer
Chemical agents that kill a variety of microorganisms.
question
What does statis/static mean?
answer
To stand still.
question
What is bacteristatic?
answer
Prevent the growth of bacteria.
question
What is fungistatic?
answer
inhibit fungal growth.
question
What is a microbistatic?
answer
Materials used to control microorganisms in the body such as antiseptics.
question
What is microbial death?
answer
When cell structures become dysfunctional and the cell becomes irreversibly damaged

OR

a cell can no longer reproduce under ideal environmental conditions.
question
What are the factors that influence action of antimicrobial agents?
answer
1.)The number of microorganisms
2.)The nature of the microorganism
3.)The temp and pH of environment
4.)The concentration of the agent
5.)The mode of action of the agent
6.)The presence of solvents, interfering organic matter and inhibitors.
question
What are the 4 ways agents work?
answer
1.)Affect the cell wall
2.)Affect the cell membrane
3.)Affect protein synthesis
4.)Affect protein function
question
How do agents affect the cell wall?
answer
By blocking its synthesis, digesting it or breaking it down. Once gone, the cell is easily lysed.
question
What is an example of an agent that effects a cell wall?
answer
Penicillin, cephalosporins, vancomyocin, detergents, and alcohol.
question
How do agents affect the cell membrane?
answer
They disrupt the normal transport of materials in/out of the cell or allow the free flow of substances in/out of the cell.
question
What is an example of an agent that effects the cell membrane?
answer
Surfactants - detergents that easily open holes in the membrane
question
How do agents affect protein synthesis?
answer
They disrupt DNA transcription or replication OR disruption of the translation in the ribosomes.
question
What is an example of the disruption of DNA transcription/replication?
answer
Ciprofloxacin, sulfonamides, and radiation (gamma, UV and X)
question
What is an example of the disruption of the translation in the ribosomes?
answer
Streptomycin, tetracycline, chloramphenicol, and erythromycin.
question
How do agents effect protein fucntion?
answer
Generally work by altering protein's natural structure (conformation).
question
What is denaturation?
answer
Involves breaking the bonds within the protein to disrupt its conformation.
question
What is coagulation?
answer
Aggregation of proteins resulting in a non-functioning mass.
question
What are the 4 methods of physical control?
answer
1.)Heat
2.)Cold/Desiccation
3.)Radiation
4.)Filtration
question
Generally, ______ temperatures are microbicidal and ______ temperatures are microbistatic.
answer
higher/lower
question
What are the common methods of moist heat control?
answer
1.)Pressurized Steam
2.)Non-pressurized Steam
3.)Pasteurization
4.)Boiling water
5.)Dry heat
question
What is pressurized steam? What does it destroy? What is it used on?
answer
Increasing the pressure of steam allows for higher temps and better microbe killing. It destroys vegetative cells, spores and viruses. Sterilizes heat-resistant materials and any material that will be discarded.
question
What is pressurized steam NOT effective against? What is an example of a pressurized steam method?
answer
Not effective in sterilizing substances that repel or absorb moisture (waxes, oils, powders.)

Autoclave is a commercial device used for steam-heat sterilization. Average setting = 15 psi 121 celcius for 15 minutes.
question
What is non-pressurized steam? What does it kill? What is it ineffective against?
answer
Intermittent sterilization. Destroys vegetative cells and viruses but NOT spores. Used to sterilize heat sensitive culture media. Inneffective against objects that don't allow microbial growth but can disinfect them.
question
How does non-pressurized steam work?
answer
Exposed to free-flowing steam for 30-60 minutes, incubate for 23-24 hours, treat again and repeat for 3 days in a row.
question
What is pasteurization?
answer
Technique in which heat is applied to liquids to kill potential agents of infection and spoilage while maintaining flavor and food value.
question
What does pasteurization sterilize?
answer
Does not STERILIZE the liquid as spores, thermoduric and thermophilic organisms still remain.
question
What is flash pasteurization?
answer
71.6 celcius for 15 seconds - common in Asia
question
What is Batch pasteurization?
answer
63-66 celcius for 30 minutes - common in USA
question
What is Ultrahigh-temperature pasteurization?
answer
134 celcius for 1-2 seconds. Allows milk to be stored for long periods at room temperature aka coffee creamer.
question
What is the goal of pasteurization?
answer
To prevent the transmission of milk-borne diseases from infected cows and milk handlers.
question
Does pasteurization kill ALL microbes?
answer
no
question
What does boiling water do? How does it work? What is its downside?
answer
For DISINFECTION NOT STERILIZATION. Expose materials to boiling water for 30 minutes. After 10, all non-spore forming pathogens and most viruses. Decontaminates suspect drinking water. Biggest downside = recontamination.
question
What are the 2 methods of dry heat sterilization?
answer
Incineration and Dry Oven
question
What does incineration do?
answer
Ignites and reduces microbes to ashes and gas. Common practice in microbiology lab - flaming the loop. Hospitals use it to eliminate infectuous waste products.
question
What does dry oven do?
answer
Electric coils radiate heat within an enclosed compartment. Sterilization occurs at 150-180 celcius for 2-4 hours. Is used on heat-resistant items that do not sterilize well with moist heat.
question
What does refridgeration and freezing do?
answer
Designed to SLOW microbial growth. Common in food processing and storage. Not considered a viable method of sterilization or disinfection.
question
What does dessication do?
answer
Drying. Inhibits growth by removing water. Inhibits the spread of most pathogens but not all of them. Not considered a viable method of sterilization or disinfection.
question
What is lyophilization?
answer
Mixture of freezing and drying. Used to preserve microbes and other cells for long periods of time.
question
What is radiation?
answer
Energy emitted from atomic activities and dispersed at high velocity through matter or space.
question
What are the 2 categories of radiation?
answer
Ionizing and Non Ionizing
question
What is ionizing radiation?
answer
Excites the electrons to the point that they are ejected from the molecule entirely causing the formation of ions. DNA is the most sensitive.
question
Ionizing radiation causes ______ _______ ______ in organelles and the production of toxins.
answer
lethal chemical changes.
question
What is ionizing radiation used in?
answer
Sterilization of commercial food products.
question
What are the potential problems with ionizing radiation?
answer
Potential change in taste and nutritional value, and introducing undesirable chemical rxns. Causes potential danger to operators and possible damage to materials.
question
What is ionizing radiation the preferred method of sterilization for?
answer
Drugs and tissues by hospitals.
question
What are some examples of ionizing radiation?
answer
Gamma rays, x rays, cathode rays
question
What is non-ionizing radiation?
answer
Excites electrons causing them to jump orbitals but don't leave the molecule. Leads to abnormal linkages and bonding. DNA is very succeptible. Leads to Thymine dimers.
question
What is non-ionizing radiation usually used for?
answer
Disinfecting air. Commonly seen in lights in hospitals, operating rooms, schools, food prep areas, and dental offices. Can treat liquids.
question
Does non-ionizing radiation pass easily through solids? What is its threat?
answer
No but can be used in some applications. Can be damaging to human skin.
question
What is filtration effective in removing? How does it work?
answer
Microbes from the air and liquids. Fluid strained through a filter with openings large enough for fluid but too small for microorganisms.
question
When is filtration used?
answer
Prepare liquids that can't withstand heat such as serum, blood products, vaccines, IV fluids, and enzymes. Can decontaminate beverages without altering their taste. Water purification. Can remove airborne contaminates.
question
What are sounds waves used for?
answer
Disrupt cell structure. Sonicator. Gram negative bacteria are most susceptible. NOT A RELIABLE SOURCE OF DISINFECTION/STERILIZATION BY ITSELF
question
What is osmotic pressure used for?
answer
Salt concentration. Involves the use of salt to create a hypertonic environment. Results in water leaving the cell which inhibits cellular processes.
question
What are the chemical agents of microbial control?
answer
1.)Halogens
2.)Phenols/Derivatives
3.)Alcohols
4.)Oxidizing agents
5.)Surfactants/Detergents
6.)Heavy Metal Compounds
7.)Aldehydes
8.)Gaseous Sterilants and Disinfectants
question
How do the halogens work? What are some examples? DISINFECTANT
answer
They generally disrupt microbial enzyme function. They are effective against vegetative cells and some spores. Ex: Household bleach and betadine
question
How do the phenols work? What are some examples? DISINFECTANT
answer
Effective against vegetative cells but not spores. They denature proteins and disrupt cell membranes. Have nasty odor and bad side effects. Ex: Orthophenylphenol (lysol), hexylresocrinol (throat lozenges), hexochlorophene (Phisoderm)
question
How do alcohols work? What are some examples? DISINFECTANT
answer
Effective against vegetative cells but NOT spores. Mostly inactivation of enveloped viruses than nonenveloped viruses. Work by denaturing proteins and disrupting cell walls and membranes. Disadvantage - evaporate quickly. Isopropanol and ethanol commonly used in 70-95% mixtures. 100% alcohol dehydrates cells and inhibits their growht.
question
How do oxidizing agents work? What are some examples? DISINFECTANT.
answer
Bactericidal, virucidal, fungicidal and sporicidal in higher concentrations. Effective against anaerobic organisms. Used to treat drinking water and eliminate spores on surfaces. Oxidize enzymes and shuts down microbes metabolism. Ex: peroxide, ozone, paracetic acid.
question
How do surfactants/detergents work? What are some examples? DISINFECTANT
answer
Work against vegetative cells but NOT spores. Work by disrupting the cell membrane structure. Ex: soaps, detergents, mouthwash.
question
How do heavy metal compounds work? What are some examples?
answer
All work differently. Most are no longer used.

Copper - algae growth in water.

Zinc/Mercury - fungal growth in paint

Silver - oral ulcers. opthalmic gonorrhea. In plastic and steel to control microbial growth. Germicidal ointments. Catheters to prevent UTI's.

Mercury - Antiseptic
question
How do aldehydes work? What are some examples? STERILIZERS
answer
Denature proteins and inactivate nucleic acids. Glutaraldehyde - cleaning lensed instruments and some respiratory equipment. Carcinogenic. Formaldehyde - vapor sterilizes laboratories.
question
How do gaseous sterilizers and disinfectants work? What are some examples?
answer
Ethylene Oxide Gas - effective against all microbes. Reacting with proteins. Useful in sterilizing fabrics, implantable objects and any heat or moisture sensitive items. Exposure time = 3-12 hours for full sterilization. GAS IS TOXIC, EXPLOSIVE, POTENTIALLY CARCINOGENIC.
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New