Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chapter 11
Physical and Chemical Control of Microbes
| Term | Definition |
|---|---|
| Historical microbial control methods | salting food, smoking food, pickling food, drying food, exposing food, clothing, and bedding to sunlight |
| Four possible outcomes of microbial control outside the body | sterilization, disinfection, antisepsis, decontamination |
| Sterilization | the destruction of all microbial life |
| Disinfection | destroys most microbial life, reducing contamination on inanimate surfaces |
| Antisepsis (degermation) | destroys most microbial life reducing contamination on a living surface |
| Decontamination (sanitization) | the mechanical removal of most microbes from an animate or inanimate surface |
| Bacterial endospores | considered the most resistant microbial entitles destruction of endospores is the goal of sterilization |
| Sterile | process that destroys or removes all viable microorganisms, including viruses |
| Disinfection | the use of a physical process or a chemical agent (disinfectant) to destroy vegetative pathogens but not bacterial endospores normally only used on inanimate objects |
| Sepsis | the growth of microorganism in blood and other tissues |
| Asepsis | any practice that prevents the entry of infectious agents into sterile tissues and prevents infection |
| Antisepsis | application of chemical agents (antiseptics) to exposed body surfaces and surgical incisions to destroy or inhibit vegetative pathogens |
| Germicide and microbicide | chemical agents that kill microorganism |
| Bactericide | a chemical that destroys bacteria expect for those in the endospore stage |
| Fungicide | kills fungal spores, hyphae, and yeast |
| Virucide | inactivates viruses, especially on living tissues |
| Sporicide | capable of killing endospores |
| Bacteristatic agents | prevent the growth of bacteria on tissues or objects in the environment |
| Fungistatic chemical | inhibit fungal growth |
| Microbistatic agents | chemicals used to control microorganisms in the body (antiseptics and drugs) |
| Sanitization | (decontamination) any cleansing technique that mechanically removes microbes and debris reduces contamination to safe levels |
| Sanitizer | soap or detergent used to sanitize |
| Antisepsis/degermation | (decontamination) reduction of the number of microbes on the skin involves scrubbing skin or immersing it in chemical or both |
| Critical medical devices | expected to come into contact with sterile tissues |
| Semicritical medical devices | come into contact with mucosal membranes |
| Noncritical medical devices | those that do not touch the patient or are only expected to touch intact skin |
| Death of microscopic organism | harder to see, no conspicuous vital signs, lethal agents don't alter the overt appearance of microbial cells, loss of movement cant be used to indicate death |
| Factor that affect death rate | number of microorganisms, nature of the microbes in the population, type of microbial growth, temperature and pH of the environment |
| Cellular targets of physical and chemical agents | cell wall, cell membrane, cellular synthetic processes (DNA,RNA), proteins |
| Damage to the cell wall | blocking cell wall synthesis, digesting the cell wall, breaking down the surface of the cell wall detergents and alcohols disrupts the cell wall |
| Surfactants | polar molecules with hydrophilic and hydrophobic regions opens up leaky spots |
| Native state | normal 3-dimensional configuration of a protein that allows proper function |
| Denature | disruption of proteins, rendering them nonfunctional breaking of the bonds that maintain the secondary and tertiary structure |
| Heat | the most widely used method of microbial (others) -radiation -filtration -ultrasonic waves -cold |
| Moist heat | hot water, boiling water, steam temp: 60C to 135C |
| Dry heat | air with low moisture content that has been heated by a flame or electric heating coil temp: 160C to several thousand degree Celsius lack of water increases stability of some protein configurations, necessitation higher temperature |
| Moist heat | 121 c temperate 15 minutes (time 2 sterile ) |
| Temperature and length of exposure | should be considered for adequate sterilization higher temp. allow shorter exposure times lower temp. require longer exposure times |
| Thermal death time | shortest length of time required to kill all test microbes at a specified temperature |
| Thermal death point | lowest temp required to kill all microbes in a sample in 10 min |
| Cold treatment | merely retards the activities of most microbes most are not adversely affected by gradual cooling, long term refrigeration, or deep freezing |
| Desiccation | dehydration of vegetative cells directly exposed to normal room air delicate pathogen can be killed by desiccation can preserve food |
| Lyophilization | combination of freezing and dying |
| Radiation | energy emitted from atomic activities and dispersed at high velocity through matter or space -gamma rays -X rays -ultraviolet radiation |
| Irradiation | bombardment of microbes with radiation |
| Ionizing radiation | radiation ejects orbital electrons from an atom, causing ions to form causes the most damage to proteins |
| Nonionizing radiation | excites atoms, raising them to a higher energy state |
| Cold sterilization | ionizing radiation used as an effective alternative for sterilizing materials |
| Ultraviolet (UV) radiation | not as penetrating as ionizing radiation ranges from 100 nm to 400 nm |
| Effects of UV radiation | initially absorbed by DNA form pyrimidine dimers |
| Filtration | an effective method to remove microbes from air and liquids |
| Osmotic pressure | adding large amounts of salt or sugar to foods creates a hypertonic environment "cured" meats are treated with high salt concentrations so they can be kept long periods without refrigeration high sugar in jams and jellies has same effect |
| Antimicrobial chemicals | solids or gaseous antimicrobial chemicals are dissolved in water, alcohol, or mixture of the two |
| Aqueous solution | containing pure water as the solvent |
| Tinctures | antimicrobial chemicals dissolved in pure alcohol or water-alcohol mixture |
| Desirable qualities of a germicide | rapid action in low concentration, solubility in water or alcohol and long-tem stability, penetration of inanimate surfaces to sustain a cumulative or persistent action |
| High-level germicide | kill endospores, sterilants if properly used, critical items that are not heat-sterilizable. catheters, heart-lungs equipment |
| Intermediate level germicides | kill fungal but not bacterial spores, resistant pathogens such as the tubercle bacillus and viruses respiratory equipment, thermometers |
| Low-level germicides | vegetative bacteria, vegetative fungal cells, some viruses. Electrodes, straps, furniture that touches skin but not mucous membrane |
| Factors affecting the microbicidal activity of chemical | nature of microorganism being treated, nature of material being treated, degree of contamination, time of exposure, strength and chemical action of the germicide. |
| Halogens | fluorine, bromine, chlorine, iodine |
| Chlorine and its compounds | -Gaseous chlorine (Cl2) -Hypochlorites (ClO1) -Chloramines (NH2Cl) *kill bacteria, endospores, fungi, viruses |
| Hypochlorite | broadly used in industry and allied health household bleach is a weak solution of sodium hypochlorite |
| Chloramines | used as alternatives to pure chlorine in water treatment |
| Aqueous iodine | topical antiseptic, treatment for burned skin |
| Iodine tincture | used in skin antisepsis |
| Iodine tablets | disinfecting water |
| Phenol | first used as the major antimicrobial chemical toxic and irritating side effects |
| Phenolics | destroy vegetative bacteria, fungi, and some viruses too toxic to use as antiseptics |
| Ethyl alcohol (70%) | skin degerming and disinfection of some types of medical equipment evaporation rate limits effectiveness |
| Surfactants (detergents) | limited microbicidal power, activity due amphipathic nature of the molecule, varied effects, activity reduced by the presence of organic matter |
| Quaternary ammonium compounds (quats) | disinfectants: mixed with cleaning agents to sanitize a variety of objects and surfaces preservations for ophthalmic solutions and cosmetics |
| Soap | weak microbicides |
| Oligodynamic | toxic in minutes quantities |
| Ethylene oxide | sterilizes and disinfect plastic and delicate hospital instruments |
| Propylene oxide | less toxic and sterilization of food |
| Dyes as antimicrobial agents | incorporated into solutions an ointments to treat skin infections |
| Aqueous ammonium oxide | detergents, cleansers, and deodorizers |
| Organic acid | used in food preservation |
| Triclosan | excreted in the urine of 75% of Americans detectable levels in groundwater sources |
| Hydrogen peroxide (H2O2) | germicidal effects are due to toxic reactive oxygen. bactericidal, virucidal, fungicidal, and sporicidal at high concentrations |
| Applications of Hydrogen peroxide | antiseptic-skin and wound cleansing, bedsore care, mouthwashes disinfectant-soft contacts, surgical implants, plastic equipment sterilization of delicate reusable instruments |
Created by:
brittanemorris2013