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Microbiology 3
3 Microbiology
| Question | Answer | |
|---|---|---|
| What 3 things does success of identification depend on? | 1. Proper specimen selection (IE wouldnt collect urine for respiratory disease) 2. Proper collection 3. Proper transport to the lab (by tube system) | |
| Who is responsible for the quality of a specimen? | The person who collects/signs the specimen | |
| What technique can you use to prevent contamination? | Aseptic techniques | |
| What area of the body do you take samples from? | The infected part - not surrounding areas | |
| Why do samples have to be refrigerated? | Because they deteriorate quickly at room temp | |
| What are the 4 consequences of improper collection? | 1. Etiologic agent may not be found 2. Agent may not be destroyed 3. Overgrowth by normal flora may mask pathogen 4. Contaminants may interfere w/ pathogen identification | |
| What does presumptive/preliminary mean? | Wont be able to identify microorganisms right away, will take awhile | |
| Confirmatory data provided through 3 steps | 1. Isolation 2. Cultivation 3. Identification Have to grow it | |
| What does Broad Spectrums mean? | Giving a lot of antibiotics and hoping it will cover most of the microbes - could lead to resistance | |
| What | 1. Microscopic morphology 2. Staining reactions 3. Cultural appearance 4. Motility 5. O2 requirements (anaero, aero) 6. Biochemical characteristics (enzymes, toxics) | |
| In terms of Gram staining, what does +++ mean? | Lots of bacteria | |
| In terms of Gram staining, what does ++ mean? | Moderate size of bacteria | |
| In terms of Gram staining, what does + mean? | Only some bacteria in sample | |
| What 3 things can a Gram stain report tell you? | 1. Identifies + or - or neither (if no cell wall) 2. Identifies morphology 3. Indicates how much there is | |
| What does morphology mean? | Studying the relation of bacteria and its structure | |
| What are the 3 steps of Reports for C&S? | 1. Gram Stain Report 2. Preliminary Report 3. Final Report | |
| What does a Preliminary Report tell you? | Identification of bacterial agent | |
| What does a Final Report tell you? | Identifies bacterial agents drug sensitivites | |
| What is the most precise way of identifying microbes? | By Genetic Analysis - looking at genetic info | |
| What if a Genetic Analysis not good for? | New pathogens - bc they dont have information on the genes | |
| What is the quickest way for identification? | Genetic Analysis | |
| What is serology? | Branch of immunology that deals w/ in vitro diagnostic testing of blood; analyzing blood samples | |
| What assumption does serology rely on? | Every antibodies (Ab) has a specific antigen (Ag) | |
| What does a specificity test study? | Focuses on only a certain target Ab or Ag and doesn't react with others | |
| What does a sensitivity test study? | Detects very small amounts of target Ab or Ag through isolation | |
| What are the 7 types of sampling methods? | 1. Swab - least invasive 2. Sputum Samples 3. Biopsies 4. Brushings 5. Lavage 6. Thoracentesis 7. Aspirations - drawing fluids out of bodies | |
| What type of material are swaps made of? | Dacron or Rayon w/ plastic shaft | |
| How do you perform a Nasopharyngeal Swab Test? | Insert swab gently through nostril parallel to the palate & aim downwards. Swab left for 10 seconds | |
| How do you perform an Oropharyngeal Swab Test? | Insert into mouth, swab posterior pharynx and tonsil area | |
| During an Oropharyngeal Swab test, what area do you void? | The tongue | |
| How many microbes does a Sputum Sample contain and what happens of you have more? | 1-2, any more will be considered contaminated | |
| What kind of cells line the deep part of the respiratory tract? | Alveolar Macrophages | |
| What kind of cells line the trachea? | Ciliated columnar epithelium | |
| How do you know if you have the right part of the respiratory system in a sputum sample? | By looking at the cells | |
| Where is the Expectorated Sputum Sample taken? | In the mouth | |
| Why do you take the Expectorated sputum sample in the morning? And what must you do beforehand? | Because thats when the bacteria buildup, and have to mouthwash to minimize contamination (bc can only have 1-2 microbes) | |
| What can you do to induce a sputum sample? | Give nebulized sterile saline (LVN or SVN) either 0.9 or 3% concentration = salt draws secretions from airway | |
| Why do you have to label an induced sputum sample? | So then the analyzers know why there's a lot of salt/saline in the sample | |
| What kind of rooms does an induced sputum sample require? | A negative pressure room | |
| What are the 3 ways you can collect samples during a Fiberoptic Bronchoscopy? | 1. Transbronchial Biopsy Specimens 2. Bronchial Brushings 3. Bronchoalveolar Lavage BAL | |
| What does the catheter/sheath do for a sterile biopsy forcep? | For cleaning | |
| What dissolves in the lungs? And which tests is it used for? | Polyethylene Glycol; used for transbronchial biopsy specimens & bronchial brushings | |
| What is the process of a transbronchial biopsy specimen? | Inserted down suction lumen of bronchoscope, once in position the forceps push through the polyethylene plug, small tissue sample take, forceps retract into sheath and sample put into tissue prep | |
| What are Bronchial Brushings usually used for? | Tumours or masses | |
| What is the process of a bronchial brushing? | Similar to transbronchial biopsy specimen, but instead the brush is cut off | |
| What does a Tissue Preparation prevent? | Tissue Decay | |
| What are the 2 types of tissue preparations? | 1. Cytology 2. Formalin | |
| What are Tissue Preparations used for? | Used to prepare/harden the tissue sample of cell specimens for microscopic exams | |
| Out of the 3 types of sputum samples, which one is the least sterile? | The BAL | |
| What is the process for a BAL? | 20 cc sterile saline injected into suction lumen of bronchoscope, specimen trap attached to suction lumen, specimen collected through aspiration | |
| What are the 3 risks that a Thoracentesis can lead to? | 1. Pneumothorax - lung collapse 2. Bleeding 3. Infection | |
| Where are the 2 areas that a Thoracentesis can be taken from? | 1. Lung Parenchyma - tissue 2. Pleural Cavity - fluid | |
| What is the process for a Transtracheal Aspiration? | 14 gauge needle w/ polyethylene catheter attached to a syringe (go into trachea w/ needle), inserted into cricothyroid membrane, tracheal sample taken | |
| What is the last resort for a sample? | Open Lung Biopsy; full surgical procedure | |
| When would you use an Open Lung Biopsy? | When all other diagnostic tools fail to identify pathogen | |
| Who regulates the Biohazards Waste? | The Ministry of the Environment | |
| What are the 2 types of Biohazards Wastes and what are some examples of each? | 1. Anatomical Wastes - tissues, blood, body fluid 2. Non-Anatomical Wastes - needles, blades | |
| What kind of needle should waste handlers get? | Hep B Immunization | |
| How do safety needles work? | Retract when you are done | |
| What are the 4 things a sharp container must have? | 1. Should not be able to penetrate walls of container 2. Not allow retrieval 3. Must meet or exceed CSA standard 4. Be labelled w/ universal biohazard symbol | |
| How can you protect yourself with managing spills and biohazard waste? | PPE and routine practices | |
| Where can you get guidelines for managing spills? | From Clinical and Laboratory Standards Institute (CLSI) | |
| What are the 5 steps to Manage a Spill? | 1. Remove obvious organic material w/ towel 2. Apply low-level disinfectant/detergant 3. Rinse area & dry using towels 4. Dispose waste in plastic lined biohazard container 5. Dispose PPE, hand hygiene | |
| What are the 3 ways for microbial control? | 1. Physical 2. Chemical 3. Mechanical | |
| What are the 3 goals for Microbial Control? | 1. Destroy pathogens - ideally 2. Remove microorganisms - realistically 3. Reduce the # of microbes in a given area | |
| What are the 4 determining factors for which antimicrobial technique will be used? | 1. Material being treated 2. Type of microbe involved 3. Microbial load/amount 4. Time available for treatment | |
| What does Sterilization mean? | Destruction/removal of all microorganisms and their spores (IE endospores) | |
| What does Sterile mean? | Material being treated for sterilization | |
| What does Disinfection mean? | Destruction of vegetative microorganisms (not actively dividing, just feeding) through chemical or physical methods | |
| What are disinfections usually used on? | Inanimate surfaces | |
| What does Disinfectant mean? | Antimicrobial chemicals specifically designed to be used on nonliving surfaces (not people) | |
| What does Contamination mean? | The presence of microbes in or on the body or objects | |
| What does Contaminant mean? | Substance that is present in an environment where it does not belong or is present at levels that may cause harmful effects to living organisms | |
| What does Decontamination mean? | Reduction or removal of chemical or biological agents | |
| What does Aseptic mean? | Growth-inhibiting agent used on tissues to prevent infections/cleaning patients or prepping areas | |
| What does Bacteriostatic mean? | Substance that interferes w/ or inhibits bacterial cell growth and reproduction | |
| What does -static mean? | Inhibits | |
| What does -cidal mean? | Kills | |
| What does Bacteriocidal mean? | Action of a substance that kills bacteria | |
| What does Microbial Death mean? | Permanent loss of reproductive capability, even under optimal growth conditions | |
| What type of bacteria is the least resistance? | Vegetative cell | |
| What type of cells are most susceptible to bacteria? | Rapidly dividing cells | |
| What are 4 common types of microbes that demonstrate low resistance? | 1. Fungal spore and Hyphae 2. Enveloped Viruses - have proteins which is what the drug targets 3. Yeasts 4. Protozoan Trophozoites | |
| What are 4 types of microbes that demonstrate moderate resistance? | 1. Protozoan cysts 2. Fungal sexual spores 3. Some Viruses 4. Some bacterial vegetative cells | |
| What are the 2 types of microbes that demonstrate high resistance? | 1. Bacterial endospores 2. Prions | |
| What is used as an indicator of sterilization? | Destruction of bacterial endospores | |
| Does higher temperature require a shorter or longer period of time for sterilization? | Shorter period of time | |
| Between dry heat procedures and moist heat procedures, which ones uses higher temperature? | Dry heat procedures | |
| What happens to the chemical reaction when temperature increases? | Increase temp = increase speed of reaction | |
| How high does the temperature go to when using it for sterilization? (Death Rate) | Up until the agent is inactivated | |
| How does pH affect the ionization of a chemical agent? | May increase or decrease the amount of agent entering the cell | |
| When is concentration reduced? | When Extraneous Organic Matter is present | |
| What is considered an Extraneous organic matter? | Saliva, blood, mucous | |
| What are the 4 types of organic matter that inhibit the actions of disinfectants and heat? | 1. Blood 2. Saliva 3. Sputum 4. Other secretion/excretions | |
| What are the 3 negative effects of an Extraneous Organic Matter? | 1. Neutralization of agent 2. Reduce agent's concentration by diluting 3. Provide shelter to microbes from physical and chemical methods | |
| What does Mode/mechanism of action mean? | An antimicrobial agent's adverse effects on cells (like cell variance) | |
| What are the 4 things that antimicrobial agents affect? | 1. Cell Wall 2. Cell membrane 3. Cellular synthetic process (DNA, RNA) 4. Proteins | |
| What are 3 ways that agents can damage the cell wall? | 1. Blocking cell wall synthesis 2. Digesting the cell wall 3. Breaking down surface | |
| What happens to a bacteria when it looses its cell wall? | Becomes very fragile and could lysis | |
| What are the 3 types of agents that disrupt the cell wall? | 1. Penicillin class of antibiotics 2. Detergents - household 3. Alcohols | |
| What type of cell wall is most susceptible to detergents and alcohols? | Gram negative cells | |
| What happens to a cell when its cell membrane becomes disrupted? | Loses its selective permeability | |
| What does surfactant mean? | A surface-active agent that forms a water soluble interface | |
| How does surfactant work as a microbial agent? | By lowering the surface tension of the cell membrane; specifically bind to the lipid layer and penetrate the internal hydrophobic region of the cell membrane = leaves holes | |
| What does microbial life depend on? | Continuous supply of proteins to function as enzymes and structural molecules | |
| What are 3 things that agents can do to cellular synthetic processes? (DNA replication) | 1. Impede DNA replication 2. Change the genetic code 3. Inhibit cell growth and reproduction | |
| What does antimicrobials do to cellular synthesis process? (DNA replication) | Inhibits the formation of proteins required in growth and metabolism | |
| What affect does antimicrobial agents have on proteins? | Disrupts or denatures them (interrupts DNA sequence and looses their native status), which causes them to create random, irregular loops and coils | |
| What are the 3 things that happens to proteins once their configuration has been altered? | 1. Active sites are blocked 2. Interferes with the bonding of substrates 3. Changes in shape inactivates enzymes | |
| What is considered a critical item for sterilizing? | Something that penetrates skin or mucous membrane | |
| What are the 4 things that are considered a critical item? | 1. Surgical Instruments 2. Cardiac Catheters 3. Implants (eg. hip replacements or boobs) 4. Items introduced into the bloodstream or another sterile site | |
| What is considered a semi-critical item for sterilizing? | Items that come in contact w/ mucous membranes but DONT penetrate (IE tooth brush, cutlery, laryngoscope) | |
| What is considered a non-critical item for sterilizing? | Items that contact only intact skin (IE stethoscope) | |
| For the 3 common types of materials & equipments that have to be disinfected, how are they all cleaned? | Critical Items - sterilized Semi-Critical Items - Cleaning & Disinfection Non-Critical Items - Cleaning | |
| What are the 5 types of physical controls for microbial growth? And which 2 are more so for the food industry? | 1. Heat 2. Cold - Food 3. Radiation 4. Drying/Desiccation - Food 5. Filtration | |
| For the physical control of heat, what is considered a Microbicidal? What's considered a Microbistatic? | Microbicidal - temps that exceed a microbes max growth temps (kills them) Microbistatic - temps below the mini. growth temp (interferes w/ growth) | |
| What does Moist Heat do to proteins? (2) | Denatures them; 1. Impairs cellular metabolism 2. Interferes w/ DNA/RNA transcritpion | |
| What has a low resistance to Moist Heat? (2) | 1. Bacterial Vegetative cell 2. Fungi | |
| What has a high resistance to Moist Heat? | 1. Bacterial Endospores (needs higher temps) - thermal death times vary | |
| What are the 2 measurements used for measuring thermal death (moist heat)? | 1. Thermal Death Time (TDT) - shortest time to kill 2. Thermal Death Point (TDP) - lowest temp needed to kill in 10 mins | |
| What are the 4 methods used for Moist Heat Control? | 1. Steam under pressure 2. Non-pressurized steam 3. Boiling Water 4. Pasteurization (IE masks) | |
| How does steam under pressure work? | Steam is pressurized to elevate temp above 100C to sterilize | |
| What type is an Autoclave? | Uses steam under pressure to sterilize | |
| What is the most common combination use in an Autoclave? | 15 psi above normal (=2 atm) and up to 121C for 15-20 mins (in autoclave) | |
| Why wouldn't you go above the recommended combination used in an Autoclave? (2) | Doesn't actually decrease the exposure time by having a higher temp, plus it could potentially damage the equipment if they are unable to handle to high temp | |
| How does the Autoclave sterilize the microbial? (What is the mode of action/effect on it) (2) | 1. Denatures the proteins 2. Destruction of membranes and DNA | |
| How would you load an Autoclave? | To allow evacuation of air and circulation of steam (in order to pressurize have to have a way for the air to be able to escape and to also pressurize the air that was already left in there) | |
| How do you know when sterilization is achieved in an Autoclave? | When the steam condenses agaisnt the objects in the chamber AND raises their temp | |
| What does the processing times depend on in an Autoclave? (2) | 1. Bulk of load 2. Fullness of chamber (example - like having a comforter/sheets in a dryer) | |
| What type of substances/materials would use a Non-pressurized Steam Chamber for sterilization? | Substances that cannot stand high temps of the autoclave | |
| What is a Tyndallization? And what is it part of? | Non-pressurized Steam; fractional sterilization designed to destroy/kill spores indirectly | |
| When would you know if the Tyndallization has been effective? | When there's no more spores | |
| What is the process for a Tyndallization - Non-pressurized steam? | Substance is exposed to flowing steam for 30-60 mins, then a mineral is introduced to allow spore germination (tricks it into coming out of its protective coating) | |
| What happens in the Tyndallization when the spore has achieved germination? | Resultant vegetative cells are then destroyed by repeating steaming | |
| What kind of spores might be able to survive Tyndallization? | Highly resistant spores (takes higher temp & longer) | |
| What is Boiling water used for? | Disinfectant - since it cannot exceed 100C | |
| What is the disadvantage to Boiling Water? | Items can become re-contaminated easily when removed from water (eg. bottles for babies) | |
| How long would you use Boiling Water for (for disinfecting)? And for what types of pathogens? | 30 mins - kills MOST (not all) non-spore forming pathogens (eg staph, TB) | |
| What would you use Pasteurization for? (2) | Usually used for fluids & anaesthesia masks | |
| What is the process for Pasteurization? (2) | 1. Heat treatment for fluids to destroy sensitive vegetative cells 2. Rapid chilling | |
| What does rapid chilling achieve in pasteurization? (2) | 1. Inhibits growth of survivors (anything we werent able to kill = at least prevents) 2. Prevents germination of spores (bc not warm) | |
| Out of the 4 types of methods used for Moist heat sterilization, which ones does not actually achieve sterilization of products? And why? | Pasteurization; doesn't actually kill endospores or thermophilic microbes | |
| What are the 2 methods used for Pasteurization? And how do they work? | 1. Ultrahigh temp (UHT) - liquid exposed to 138C for fraction of second (AKA flash method) 2. Batch method/high temp short time (HTST) - liquid exposed to 63C @ 30 mins, then cooled to 4C | |
| Out of the 2 methods used for Pasteurization, which one will most likely change the flavour and nutrient content? | HTST - UHT wont change the flavour/nutrient | |
| How does the Dry Heat method work? | Air w/ a low moisture content heated by a flame or an electric heating coil (oven) | |
| What are the temp rages for the dry heat method? For what time? | 160-170C @ 2-4 hours | |
| How does the Dry Heath method sterilize products/what is the mode of action? | Dehydrates the cell = impairs its cellular metabolic reactions & denatures it | |
| Why does the Dry Heat method use such high temp? | Because lack of water can stabilize certain proteins therefore high temps are used for microbial control | |
| What is the most accurate method used in the Dry Heat? | Incineration | |
| How does the Incineration (for Dry Heat) work? (3) | 1. Oxidizes cellular components (causes release of Oxygen) 2. Increase concentration of toxic constituents (to accumulate) 3. Denatures enzymes & other proteins (so then they're no longer functional) | |
| What is the process for using a Dry Heat - Hot Air Oven? | 1. Preheat oven 2. Load the oven to allow circulation of air 3. Cycle times vary 12 mins to 4 hours @ temp between 160-170 C | |
| What would you use a Dry Heat - Hot Air Oven for? | Items that are heat-resistant BUT don't sterilize well w/ moist heat | |
| How does the Cold method affect microbes? | Microbiostatic - slows & interferes w/ growth | |
| What is the Cold method used for? | Not for cleaning, used to preserve foods, media, and cultures | |
| How does Desiccation work? | Drying the samples by removing water from the cells = metabolic inhibition (inhibit cellular reactions) | |
| What does Lyophilization mean? | Dry freezing; for preservation by removing H2O | |
| Why is Desiccation considered a non-effective way for microbial control? | Because it just removes water from cells therefore many cells retain the ability to grow back when water is reintroduced | |
| How do Filtration methods work? | Physically removes microbes by passing a gas/liquid through a filter | |
| When is the filtration method used? | To sterilize heat sensitive liquids and air in hospital isolation units & industrial clean rooms | |
| What are the 2 methods/types for filtration? | 1. Membrane Filters 2. HEPA Filters | |
| What is the Membrane Filtration? And how does it work? | Thin membranes of plastic materials; absorbs very little of the fluid being filtered | |
| What are the pore sizes used for in a Membrane Filtration? | Coarse 8 um - ultrafine 0.01 um | |
| In a Membrane Filter, what does the smallest pore size produce? And where are they collected? | Produces sterile filtrates; collected in a sterile container | |
| What kind of pressure is required in a Membrane Filter? And what does it do? | (-) Pressure; draws liquids through the filter (vacuums) | |
| What can Membrane Filters be used for? | Used to culture bacteria separated from liquid samples | |
| What does HEPA stand for? | High Efficiency Particulate Air Filters | |
| What can a HEPA Filter be used for? | To filter out respiratory and anaesthetic gases | |
| What is the effective rate for HEPA Filters? | 99.7 um for filtering particles >0.3 um | |
| How does Radiation work? | Electromagnetic Radiation - energy as waves transmitted through materials | |
| What happens to the wavelength when energy increases? | Energy Increase = Decrease Wavelength (shorter) | |
| How does Ionizing Radiation work? | High energy radiation w/ very short WL | |
| How does Ionizing Radiation cause ionization in molecules? (4) | 1. IR acts on vital cell components 2. Splits molecules into atoms/groups 3. Splits H2O molecules into H+ & Hydroxyl radicals (highly reactive molecules) 4. Hydroxyl radicals destroy DNA & protein | |
| What are the 3 methods that are included in Ionizing Radiation? Which one is most commonly used? Which one has high/low energy & long/short WL? | 1. X-Rays - Low energy/Long WL 2. Gamma Rays - most used 3. Electron Beams - High energy/Short WL | |
| What kind of items would you use Ionizing Radiation for? | Heat-sensitive items, therefore use cold sterilization | |
| How does Non-Ionizing Radiation work? | Little penetrating power (low energy); results in the formation of new covalent bonds (from UV light) & alters protein structures (denatures it) which leads to cellular death | |
| What are the 3 types of items used in Non-Ionizing Radiation? And how effective are they? | Air - passes nicely Liquids - slightly Solids - poorly | |
| What is the dosimetre? | Device that keeps tract of radiation exposure | |
| What is the range of WL (from UV) created in Non-Ionizing Radiation? What is the lethal range? | 100-400 nm; lethal = 240-280 nm | |
| What are the 4 areas that Non-Ionizing Radiation reduces the # of microorganisms? | 1. Air and on surfaces in ORs 2. Laboratory biological safety cabinets 3. Transparent fluids (slightly) 4. Vaccines | |
| What is a useful source that can be used for Non-Ionizing Radiation? And how does it help? (2) | The Germicidal Lamp (254 nm); decreases airborne microbes by 99% (like in OR), and can treat fluids and waters | |
| What is the disadvantage to the Germicidal Lamp? | Has damaging effects on human tissues, therefore have to make sure room is completely empty | |
| What are the 3 Indicators for Achieved Sterilization? | 1. Mechanical Control - Indirect 2. Chemical Indicators - Indirect 3. Biological Indicators - Direct | |
| What is a Mechanical Control? (As an Indicator for Sterilization) | Print-out of temp, pressure, and times obtained in autoclave | |
| What is the Mechanical Control important for? | In quality control/quality assurance | |
| What is a Chemical Indicator? (As an indicator for Sterilization) | Colour change (like on tape) will occur if chemical is held @ a specific temp for a specific time | |
| What is the Biological Indicator? (As an indicator for Sterilization) | Vial added into autoclave full of endospore strip and nutrient medium (everything they need to grow). Should be gone by the time the item is sterilized | |
| What happens (w/ a Biological Indicator) if sterilization was not achieved? | Spores will return to their vegetative state, capable of reproducing | |
| What does Aqueous mean? | Chemical that uses pure water as a solvent | |
| What does a Tinctures mean? | Alcohol or water-alcohol solvent mixture (adding alcohol) - usually on antiseptics | |
| What are the 2 types of Antimicrobial Chemicals that are either Aqueous or Tincutures? | 1. Gaseous 2. Solids | |
| What are the 7 factors that affect Antimicrobial Chemicals? | 1. Population Size 2. Population Composition 3. Duration of Exposure 4. Local Environment (IE biofilms present) 5. Concentrating of the Chemical Agent (increase concentration, increase effectiveness) 6. Temp 7. Organic Matter (body fluids) | |
| What are the 3 levels for Chemical Decontamination? | 1. High Level Disinfectants 2. Intermediate Level Disinfectants 3. Low Level Disinfectants | |
| What does Sporicidal mean? | Tending to kill spores | |
| What is the High Level Disinfectants used for? (Levels of Chemical Decontamination) And what are they used with? | Used to kill endospores (sporicidal) therefore end product will be sterilent. Used on medical devices that are heat-sensitive and critical items | |
| What is the Intermediate Level Disinfectants used for? (Level of Chemical Decontamination) And what are they used with? | Used to kill fungal spores, resistant pathogens (like TB), and naked viruses | Used on respiratory equipment and thermometers; and with semi-critical items |
| What is the Low Level Disinfectants used for? (Levels of Chemical Decontamination) And what are they used with? | Eliminate only vegetative bacteria, vegetative fungal cells and some viruses (low resistance) | Used to clean electrodes, furniture, surfaces; and w/ non-critical items |
| What are the 2 tests involved with evaluating disinfectants? | 1. Use-Dilution Test 2. Disk-Diffusion Test | |
| What is the Use-Diltution test looking for? And what is the process of it? | Tests the effectiveness of disinfectant; good disinfectant will have no re-growth | 1. Smear bacteria across the area 2. Then expose it to a cleaning agent 3. After contact time, disinfectant neutralized and surface incubated (warmed) |
| What is the process for a Disk-Diffusion Test? | 1. Filter paper disk soaked w/ chemical disinfectant/antiseptic 2. Placed on agar plate 3. Zone of Inhibition | |
| What are the 4 things that the Zone of Inhibition is variable & dependant on? What's included in the Incubation Conditions (3)? | 1. Growth Medium (agar) used 2. Microbial load 3. Concentration of chemical used 4. Incubation Conditions (were appropriate for that bacterium) | a) Time b) Temp c) Atmospheric conditions (anaero, ana) |
| What are the 8 types of Commonly Used Chemicals? | 1. Alcohols 2. Cl compounds 3. Iodine Compounds (surgery) 4. Glutaraldehyde 5. Peroxides 6. Ethylene Oxide (ETO) 7. Phenotics 8. Possible: ClO2 | |
| What type of Chemical Disinfectant level is Alcohol (Commonly used Chemical)? And where is it used? (2) | Intermediate Level Disinfectant - used on skin prior to injections & to disinfect thermometers | |
| What type of cells is Alcohol (a commonly used chemical) effective agaisnt? | Vegetative cells (TB) | |
| What is the range used for Alcohol (commonly used Chemical)? And what % is it at optimum concentration? | 50-95%; optimal [ ] is 70% | |
| What must Alcohol (a commonly used chemical) be mixed with? And why? | Must be mixed with H2O to penetrate because H2O helps it get across the cell's membrane (as a carrier) | |
| What are the 3 advantages to Alcohol (a commonly used chemical)? What are the 2 disadvantages? | 1. Unaffected by the presence of Organic matter 2. Stable and easy to handle 3. No Residue | 1. Ineffective agaisnt spores or Hep B 2. Flammable |
| What is a Halogen Compound? And what does it act on? | Strong oxidizing (releases O2 as they work) agents that form salts when combined w/ H ions | Act on amino acids and enzymes (proteins) - denatures |
| What are the 2 types of classes that the Halogen Compound is part of? | 1. Chlorine 2. Iodine | |
| What are Chlorine Compounds (a commonly used chemical) also known as? And what do they target? | AKA bleach (hypochlorite); 1% targets vegetative cells, endospores, fungi, and viruses - STRONG OXIDIZING AGENT | |
| What are the 3 advantages to Chlorine Compounds (a commonly used chemical)? And what are 6 disadvantages? | 1. Inexpensive 2. Good Deodorant 3. Readily available - no training | 1. Corrosive for steel 2. Relatively unstable 3. Aggravating to skin 4. Ineffective at alkaline pH 5. Activity reduced by organic matter 6. Irritating odor and residue |
| What are the 4 things that Iodine (a commonly used chemical) is effective agaisnt? | 1. Vegetative bacteria 2. Viruses 3. Fungi 4. Amoebae | |
| When using an Iodine compound (a commonly used chemical), what can it be inactivated by? | Organic material | |
| What is the Tincture mixture of an Iodine Compound (a commonly used chemical)? And what are the 4 disadvantages? | 2% Iodine combined w/ 70% alcohol to act as an antiseptic | 1. Staining; brownish/orangish colour 2. Residue 3. Toxic if ingested 4. Allergic reactions |
| What is considered to be an Iodophor? And what is its 4 advantages? | Iodine mixed w/ a surface active agent from which the iodine will be released slowly; INCREASES penetration | 1. Water soluble 2. Less prone to staining or irritating skin (gentler version of iodine) 3. No allergies 4. Non-corrosive |
| When is an Iodophor used? (2) | 1. As a surgical scrub 2. Pre-surgical tissue prep | |
| What are Phenolics used for (a commonly used chemical)? And what are the 2 types? | Used as an antiseptics on skin | 1. Hexachlorophene 2. Chlorhexidene |
| What are Phenolics effective against? (a commonly used chemical) | 1. Vegetative cells 2. Fungi | |
| What are the 4 advantages to Phenolics (a commonly used chemical)? What are the 3 disadvantages? | 1. Stable to heating & drying 2. Unaffected by organic compounds 3. Non-irritating to the skin 4. Leaves a residual protective film | 1. Slight odor 2. Expensive 3. Corrosive |
| What type is a Hexachlorophene? And what is it especially effective against? | Type of a Phenolics (a commonly used chemical); effective against gram (+) | |
| What is the disadvantage to Hexachlorophene? | Is absorbed by the blood stream, therefore could cause neurological damage | |
| What is the outcome for when you have a low [ ] of Hexachlorophene (type of phenolics)? And for a high [ ] ? | Low = bacteriostatic High = bacteriocidal | |
| What type is a Chlorhexidene? And what is it effective agaisnt? (3) | Type of a Phenolics (a commonly used chemical) | 1. Gram (-) 2. Gram (+) 3. Fungi |
| Out of the Hexachlorophene and a Chlorhexidene, which one is more deleterious? And why? | Chlorhexidene is less damaging because it is not absorbed by the blood stream | |
| * What is Chlorhexidene used in? And what does it treat? | Used in antibacterial mouthwash (used to clean patients mouth then suck it out); used to treat periodontal disease | |
| *** CHLORPHEXIDENE = | MILDER, LOW TOXICITY, RAPID ACTION, NOT ABSORBED INTO THE DEEPER TISSUES | |
| What is Glutaraldehyde formally known as? (a commonly used chemical) | A milder version of formaldehyde; looks like a yellow acidic liquid w/ a mild odor | |
| What is the [ ] solution for Glutaraldehyde (a commonly used chemical)? And what must you do to use it? | 2 % therefore must activate it to use it | |
| What must Glutahraldehyde be contained in? | In a fume hood; has a lid (like a garage door) and the air is vacuumed out (HEPA) to protect people that use it | |
| What is the most useful technique for using Glutarahldehyde? (a commonly used chemical) | Using it as an immersion disinfectant (dunk the equipment in there & leave for 20 mins) | |
| What are the 3 advantages to Glutaraldehyde (a commonly used chemical)? What are the 4 disadvantages? | 1. Active in organic matter 2. Non-corrosive 3. Broad spectrum activity | 1. Somewhat unstable 2. Long turnaround as prolonged exposure may be necessary 3. Irritating to tissues 4. Can be toxic |
| What are Quaternary Ammonium Compounds? And at what concentrations are they used at? | A Cationic (+) surface-active agent = decreases surface tension = breaks down membrane & causes holes | Used at low concentrations 0.1-0.2% |
| What are Quaternary Ammonium Compounds not effective against? (2) | Not effective against endospores & Hep B | |
| What are the 4 advantages to Quanternary Ammonium Compounds? And 3 disadvantage? | 1. Active in organic matter 2. Easy to handle 3. Non-irritating 4. No residue (it evaporates) | 1. Detergents can interfere w/ activity 2. Corrosive 3. Lower [ ] can support bacterial growths |
| What are Peroxides (a commonly used chemical)? | Oxidizing agents which inactivate essential proteins (destroys anaerobic bacteria) | |
| As a disinfectant, what are the [ ] ranges that Hydrogen Peroxide can be used at? | 6-25 % | |
| When using as an Antiseptic, what is the [ ] that Hydrogen Peroxide can be used at? | 3% | |
| What are the 2 types of Peroxides (a commonly used chemical)? And what are they used for? | 1. Zinc Peroxide - irrigation of deep wounds 2. Benzoyl Peroxide - deep wounds & acne | |
| Out of the 8 types of commonly used chemicals, which one is the most important? | ETO | |
| What is the boiling point and RH for ETO (a commonly used chemical)? | Bp = 10.8C RH = 33% | |
| What can you dilute ETO (a commonly used chemical) with? And what will this achieve? | Can dilute with 10% Carboxide and 20% Oxyfume; dilute to decrease explosion | |
| What are the 2 things that ETO (a commonly used chemical) is used for? | 1. Heat-sensitive medical 2. And Dental equipment | |
| What are the 2 indicators used for ETO (a commonly used chemical)? | 1. Chemical 2. Biological | |
| What are the 2 advantages to ETO (a commonly used chemical)? What are the 4 disadvantages? | 1. Good penetrating power 2. Destroys all organisms = sterilent | 1. Direct contact can damage mucous membrane 2. Rated as a Carcinogen (cancer-causing) 3. Slow-acting (90mins-12h) 4. Long turnaround time (4h) |
| What are the 4 things that Chlorine Dioxide (ClO2) (a commonly used chemical) is effective against? | 1. Vegetative bacteria 2. Fungi 3. Viruses 4. Endospores * everything but prions | |
| What does it mean by ClO2 being an Alkylating agent? | Removes a H ion to activate chemical (IE CH4 - CH3) | |
| What are the 4 uses for ClO2 (a commonly used chemical)? | 1. Treat drinking water 2. Wastewater 3. Food-processing equipment 4. Medical waster * Used to decontaminate Senate office | |
| What is the biological indicator for Dry-Heat Sterilization - Hot air oven? | Bacillus Subtilis | |
| What is the Dry-Heat Sterilization - Hot air oven incubated at? | 37C | |
| What are the 3 advantages for Dry-Heat Sterilization - Hot air oven? What are the 4 disadvantages? | 1. Safe for metal instruments 2. Does not dull cutting edges 3. Does not rust or corrode | 1. Long cycle time for sterilization 2. Poor penetration 3. May discolour 4. Destroys heat sensitive items |
| What is the biological indicator for a Moist heat sterilization - the Autoclave? | Bacillus stearothermo..... | |
| What are the 4 disadvantages to a Moist heat sterilization - the Autoclave? | 1. Corrosion of unprotected carbon steel 2. Dulling of unprotected cutting edges 3. Packages can remain wet - would have to send back 4. Can destroy heat-sensitive materials | |
| What is the biological indicator for a Chemical Sterilizer - ETO? What is it the same as? | Bacillus Subtilis - same as dry air - oven | |
| What are the first 5 Ideal Chemical Agent Characteristics? And then 6-11? | 1. Fast-acting in low concentrations (too much could harm) 2. Stable in the presence of Organic Substances (bodily fluids) 3. Broad-spectrum microbial action (works over large audience) 4. Non-toxic to humans & animals (household) 5. Penetrability 3. | 6. Easy to prepare and stable once prepared 7. Cheap & readily available 8. Odorless or pleasant odor 9. Compatible w/ soaps and detergents (prewiping) 10. Residual effect 11. Stable pH and temp changes |
Created by:
alexmanikus