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Exam Four

Microbiology Lecture

Antisepsis? Reduction of the number of pathogens on living tissues
Aseptic? An environment or procedure that is free of pathogens.
Suffix -cide? Destruction of a type of microbe
Suffix -cidial? Destruction of a type of microbe
Degerming? Removal of microbes by mechanical means.
Disinfection? destroying most microorganisms on nonliving tissues.
Pasteurization? use of heat to destroy pathogens and reduce the number of spoilage microorganisms on food/beverages.
Sanitization? Removal of pathogens from objects, to meet public health standard.
Suffix -stasis? to inhibit not completely destroy a type of microbe
Suffix -static? to inhibit, not completely destroy a type of microbe
Sterilization? to destroy all microorganisms and viruses on or in an object.
Microbial Death? loss of microbes in an ideal environment.
What are the categories for the action of antimicrobial agents? 1. disrupt the cell wall/membrane. 2. interrupt the cell's metabolism and reproduction by interfering with nucleic acid and proteins.
Alteration of Cell Wall? What category? the cells burst from osmosis. category one.
Alteration of Cell membrane? What category? the cells leak. category one.
Damage to viral envelopes? What category? viral replication is interrupted. category two.
Damage to nucleic acids? What category? fatal mutations occur or protein synthesis is stopped. category two.
Damage to proteins? What category? proteins are denature and lose function?
Denatured? bonds of protein molecule are broke by heat or chemicals so proteins cease to function.
Relative Susceptibility of Microbes order from Most resistant to most susceptible? 1.Prions. 2.Bacterial Endospores. 3.Mycobacteria. 4.Cysts of Protozoa. 5.Active-stage protozoa (trophozoites). 6.Gram-negative bacteria. 7.Fungi. 8.Nonenveloped viruses. 9.Gram-positive bacteria. 10.Enveloped viruses.
The effectiveness of Germicides is classified as? 1.High. 2.Intermediate 3.Low.
Why is it important to clean objects before sterilization or disinfection? feces, blood, vomit and biofilm secretions makes it hard for heat, chemicals and radiation to penetrate.
Disk Diffusion? is a type of method to determine the effectiveness of antimicrobial agents.
Zones of inhibition? areas free of bacterial growth; the wider the zone the more effective the agent is.
BSL-1 Microbes Permitted? Precautions Required? and PPE? Permitted:microbes not known to cause disease in healthy humans. Required:minimal; hand washing with antimicrobial soap an disinfection of surfaces. PPE: non required.
BSL-2 Microbes Permitted? Precautions Required? and PPE? Permitted:moderately microbes associated with human disease. Required:BSL1 plus limited acess to the lab facility and BSC. PPE:gloves, lab coat, full foot coverage, face/eye protection.
BSL-3 Microbes Permitted? Precautions Required? and PPE? Permitted:microbes associated with serious or lethal diseases. Required:HEPA safety cabinets, special lab design, HEPA-Filter. PPE:protective lab clothing, gloves, respiratory and face protection.
BSL-4 Microbes Permitted? Precautions Required? and PPE? Permitted:microbes that cause severe or fatal disease in humans. Required:seperate building or complete isolation from other areas. PPE:full body, air supplied, pressurized suit.
Physical method of microbial control are? moist heat, dry heat, freezing, refrigeration, desiccation, filtration and radiation.
Thermal death point? lowest temperature that kills all cells in a broth in 10 minutes.`
Thermal death time? time it takes to completely sterilize a volume of liquid
Decimal reduction time (D)? time required to destroy 90% of microbes in a sample.
Moist Heat? use of water to sterilize objects. It's more effective than dry heat because water is a better conductor of heat than air.
Methods of moist heat? boiling, autoclave and pasteurization.
Autoclaving? pressure is applied to boiling water to get a higher temperate. The higher the pressure the hotter the temperature. All microbes can be destroyed in autoclaves. it can also be used to sterilize media and biohazard waster.
Autoclaving Operation? time: 10minutes. temperature: 121 C. pressure: 15psi(pounds per square inch)
How to test for proper operation of Autoclaves? 1.autoclave tape. 2.beads that melt. 3.endospore test ampule
How does endospores test ampule work? a tube is placed in autoclave. the flexible plastic vial is squeezed by the amount of pressure in the autoclave, the flexible vial breaks the ampule that within it to mix with the endospore slide. if the color of the medium is yellow (pos.) or red (neg.)
Why is endospores strip used to test autoclaves sterility? Bacterial endospores are the most resistant forms of life. if the autoclave is able to kill the most resistant, a scientist can be confident that any other microorganisms is killed.
Why does the medium turns yellow in Endospores test ampule? a yellow results means endospores are still alive, meaning the autoclave didn't kill the most resistant microorganism. the metabolic waste of the endospores will lower the PH level in the medium to change the color.
Pasterurization? non sterilization that kills pathogens and reduce microbial spoilage of food/beverages. Termoduric acid and Thermophilic bacteria can survive pasteurization.
Ultrahigh-temperature sterilization (UHT)? flash heating of liquids to rid all living microbes.
Dry Heat? sterilize powder, oil or materials that can be damaged by steam by using an oven or incinerator. Dry heat requires a higher temperature and takes longer times than moist heat.
Refrigeration? Freezing? Lyophilization? 1.halts growth of most pathogens. 2.inhibits microbial metabolism. 3.combination of freezing and drying; keeps organisms viable for reconstitution later.
Dessication? drying out; inhibits microbial growth.
Filtration? sterilize heat-sensitive materials and used to prevent air born contamination(surgical mask/HEPA-filters).
Radiation? has two categories 1.Ionizing:create ions that denature DNA 2.Nonionizing:make new covalent bonds that affects structure of proteins an nucleic acid.
What are chemical agents used for? disinfection, antisepsis and preservation
What organisms are resistant to chemicals? fungal spores, endospores and protozoan cysts.
What are the 8 chemicals used for antiseptics and disinfectants? 1.phenol/phenolics. 2.alcohols. 3.halogens. 4.oxidizing agents. 5.surfactants. 6.heavy metals. 7.aldehydes. 8.gaseous agents.
Phenol? Phenolics? Bisphenolic? Phenol:also called carbolic acid is a natural occurring molecule. Phenolics: synthesized from phenol. less odor and greater efficacy. Bisphenolic: 2 covalently linked phenolic that is found as an active ingredient in Lysol.
What 2 oils are also phenolic and is used for antiseptic? Pine and Clove.
What problems does Phenol/Phenolics have? bad odor, irritate skin and can cause brain damage in infants.
What is the common used alcohol for microbial control? 1.Isopropanol: rubbing alcohol. 2.Ethanol: drinking alcohol.
Alcohol function is? to denature proteins. requires water in order to denature so 70-90% alcohol is more effective than 100% alcohol.
Halogen? Types? reactive nonmetallic chemical elements. Type: 1.iodine. 2.chlorine. 3.bromine. 4.fluorine.
Iodophor? Example? iodine containing organic compound that slowly releases iodine. Betadine is an example.
Chlorine Treatment and Resistances ? Chloramines? TX:used for swimming pools, drinking water and waste water. Resistant:all protozoan cysts, bacterial endospores and viruses. Chloramines:is a combination of chlorine and ammonia that is used in wound dressing.
Bromine? preferred over chlorine to disinfect hot tubs because it evaporates slower in hot temperatures.
Fluorine? Treatment? Fluoride: disrupts metabolism of microbes in dental plaque biofilms. TX:drinking water and toothpaste.
Oxidizing Agents? Types? kill microbes by oxidizing enzymes by removing the organisms electrons. Types:hydrogen peroxide, ozone and peracetic acid.
Hydrogen Peroxide? used for disinfectants not for antiseptics.
Ozone? Treatment? when oxygen gets and electrical discharge it generates 03 which is an ozone. its more effective than chlorine but more expensive. TX:drinking water.
Peracetic acid? an effective sporocide that sterilizes surfaces. used for medical equipment.
Surfactants? Types? reduce surface tension of solvent to make it better at dissolving solute molecules such as dirt, oil and bacteria. Types: soap and detergent.
Soap? Antimicrobial soap? Detergent? Quat? Soap:good for degreming, poor antimicrobial agent. Antimi:antiseptic but must be left on an surface for 2mins to work. Detergent:more soluble in water. Quat:disrupt cell membranes, tx Gram (+), resistant to mycobacteria, naked viruses and endospores.
Heavy Metals? antimicrobial and denature proteins. Types: zinc, silver, arsenic, mercury and copper.
Silver? Mercury? Copper? Silver:antimicrobial in burn cream, surgical dressings and catheters. Mercury:metabolic poison used to preserve vaccines. Copper:effective algicide to control algal growth in reservoirs, water storage tanks and pools.
Aldehydes?Types compounds -CHO that denature proteins and inactivate nucleic acid. Types 1.Gluteraldehyde 2.Formaldehyde(formalin)
Gluteraldehyde? Foraldehyde? 1.Gluteraldehyde:kills bacteria, viruses, fungi. disinfect med/dental equipment. 1.Formaldehyde(formalin):used for embalming, disinfect isolation room, surgical equipment and kidney dialysis machines. Problems:irritate mucous membrane and cancer.
Gaseous Agents? used when items cannot be sterilized by using heat or water soluble chemicals. sterilizes mattresses, pillows, heart-lung machine componet, artificial heart valve and catheters.
Ethylene Oxide? gas that used as gaseous sterilant. the problems are hazardous, explosive, toxic and carcinogenic.
Protozoa? Eukaryotic unicellular microorganism that has DNA for nucleic acid, metabolic with proteins yet lacks a cell wall. This microorganism however is motile; either cilia, pseudopods or flagellum
Protozoa Life Stages? starts in the Trophozoite stage where its motile(flagella, cilia, pseudopodia) and in the feeding stage. one it reaches adverse conditions it Encysts and enters Cyst stage where it is dormant. When in favorable conditions it Excyst to Trophozoite stage.
Encysts? Excyst? Encysts:forms a cyst capsule to survive harsh environment. Excyst: releases trophozoite for feeding.
Helminths? eukaryotic parasitic worms that have DNA nucleic acid, metabolic with proteins and a cell wall.
Helminths Morphology? 1.cestodes:flat, ribbon-like, segmented body. 2.trematodes:flat, leaf-like body(ovoid). 3.Nematodes: cylindrival, unsegmented body.
Hyphae? long branch filaments.
Septate hyphae? divided into cells by cross walls called spta. ech cell in these hyphae has a single nucleus.
Aseptate Hyphae? are not divided by septa, as a result they are Coenocytic (multicucleate)
Haustoria? modified hyphae form on fungi that derive their nutrients from living plants and animals.
Mycelium? tangled mass of hyphae
Dimorphic? produce both yeast and mold thallus
Pseudohyphae? buds remain attached to one another and to parent cell in long filaments.
Mycosis? infection or disease that is caused by fungi.
Dermatophytes? fungi that grows on skin, hair and nails.
Mycetomas? tumor-like infections of the skin, bones, feet and fascia.
Created by: aneshia