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39 Cards in this Set
- Front
- Back
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What is our first line of defense against infection? Why?
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Our skin because it is not normally penetrable
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What is a Biofilm?
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Community of microorganisms (same or different species) that live attached to biological surfaces.
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Where do biofims live? (three places)
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On solid surfaces with moisture, soft tissue, and air-liquid interface.
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What are the 2 basic steps to Biofilm Formation?
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1. Colonization
2. Growth |
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What are the 2 basic steps of Colonization in regards to Biofilms?
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1. Form stable association with surface
2. Lose flagella and produce polysaccharides |
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What are the 2 basic steps to Growth in biofilms?
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1. Building the 3D biofilm
2. Cells specialize |
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In biofilms, cells specialize into what 4 structures?
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1. Fixed cells
2. Motile cells 3. Pillars 4. Monolayer cells |
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What are 4 benefits of living in a Biofilm?
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1. Variety of habitats available
2. More resistance to toxins (antibiotics, bleach, etc) 3. Specialized structures - division of labor 4. Easy to transmit genetic materials (increased conjugation + spread of antibiotic resistance) |
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Cells communicate through what?
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Diffusible products
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Communication is especially important when what is true?
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Space is limited!
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What is the overall maximum ppm of ethylene oxide residue limit on medical devices? What is the max for intrauterine devices?
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250 ppm with 5 ppm being the max for intrauterine
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What must you do when plastic is sterilized in EtO?
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You have to let it sit after exposure for EtO to diffuse out.
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How many minutes is needed to achieve a 10^-6 sterility assurance level?
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100 minutes
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What is SAL?
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Sterility Assurance Level is the level in which sterility is ensured to a certain point.
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What is Sterility?
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A condition characterized by the absence of ALL living organisms like bacteria, yeast, mold, and viruses.
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What is Bioburden?
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The number of viable microorganisms on the implant material/device prior to sterilization.
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What is Sterility Assurance Level?
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The probability that a given implant material will remain nonsterile following exposure to a given sterilization process.
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What is the accepted MAXIMUM SAL for implants?
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10^-6
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What are the 3 considerations for choosing a specific sterilization method?
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1. Implant integrity
2. Packaging integrity 3. Maintaining SAL criterion |
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What are 5 Sterilizing Methods?
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1. Autoclave - steam
2. Ethylene Oxide (EtO) 3. Radiation 4. Gas Plasma/Ozone 5. Vapor phase hydrogen peroxide |
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What is the limitation of EtO?
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Produces carcinogens that are not environmentally friendly and thus be removed carefully.
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Why must you let devices sit for a long period of time after sterilization treatment with EtO?
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Because EtO clings to surfaces and diffuses slowly once implanted and that's REALLY BAD.
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What are the four molecular sequences in bacterial attachment?
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1. Attachment
2. Adhesion 3. Aggregation 4. Dispersion |
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What can Biofilms do when they form long strands?
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They can form streamers that then break off and float away causing more biofilms to be made.
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How long can it take biofilms to form?
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Few minutes to a few months!
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What are the 5 steps with timing of bacterial growth on substrates?
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1. Reversible adsorption of bacteria (seconds)
2. Irreversible attachment of bacteria (sec-min) 3. Growth & Division of Bacteria (hrs.-days) 4. Exopolymer production & Biofilm formation (hrs.-days) 5. Attachment of other organisms to biofilm (days-months) |
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What are the 3 processes of tissue integration and bacterial adhesion?
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1. Biochemically parallel
2. May be competitive 3. May be mutually exclusive |
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What is the Race for the Surface?
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The race of various components present on the surface to adsorb to the surface.
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What are the four components of an Operating Room?
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1. Built to maintain sterility
2. Non-porous surfaces 3. Specialized ventilation 4. Sterilized gowns and tools |
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What is the one distinguishing feature of infection from inflammation?
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The production of pus or suppuration.
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What is Pus?
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Massive numbers of neutrophils and macrophages that phagocytosed as much bacteria as possible and then died
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If infection is sustained over time, what can happen?
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Fibrous tissue may form around the liquefied infectious region to encapsulate bacteria and prevent the spread - an abscess
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Why do abscesses move to the surface?
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As they grow, they grow in the direction that offers the least resistance to movement which is usually toward fatty tissue and skin
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What are the 3 types of infection associated with implants?
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1. Superficial immediate infections
2. Deep immediate infection 3. Deep late infection. |
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What is superficial immediate infection?
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Infections near or on the skin and is caused by bacteria that normally populate the skin like sutures!
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What is Deep immediate infection?
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Infection that occurs after invasive surgery like implantation procedures caused by relocation of skin bacteria into the wound.
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What is Deep late infection?
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Infection that occurs months or years after surgery in areas that had previously showed no signs of trouble.
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Why are deep late infections so troublesome?
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They can be hard to treat due to their location.
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What are some ways researches are designing materials to discourage bacterial adhesion?
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1. Changing geometric factors on the implant surface
2. Making materials that release antibiotics |
