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74 Cards in this Set
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Fungi importance |
important as nosocomial infections and as opportunistic infection of immunocompromised few are primary pathogens |
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nosocomial infections |
infection that can be acquired in a hospital |
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opportunistic infections |
usually part of normal flora, but when they get to a wrong spot, for ex. an IV punture spot where there isn't supposed to be bacteria, they can contaminate even f they are weak |
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fungi and benefits in nature |
decomposition of plant matter edible mushrooms |
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fungi and practical uses |
leavening agent in bread fermentation of beer/wine |
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cells walls of fungi: chitin |
stains with calcium binding agents- Calcoflour white- for rapid identification of fungi in clinical specimens |
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cells walls of fungi: ergosterol |
similar to cholesterol. we use this to treat fungal infection, it prevents ergosterol from creating more ergosterol in fungus and thus fungi can't multiply b/c it can't make new cell walls |
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antivirals that affect ergosterol synthesis |
1. Amphotericin B 2. Azoles 3. Nystatin |
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3 types of fungi |
1. moulds 2. yeasts 3. thermally dimorphic |
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thermally dimorphic |
mould at 20 degrees C yeast at 37 degrees celsius |
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molds |
body of fungus called "thallus," masses of hyphae e.g. white powdery layer on moldy fruit |
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molds- coenocytic hyphae |
one big mold cell with multiple nuclei |
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molds- septate hyphae |
individual cells |
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yeasts |
oval or spherical in shape |
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yeast reproduction |
reproduce by budding |
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psuedohyphae |
a line of cells that form if buds fail to detach |
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candida albicans use of pseudohyphae |
candida albicans may attach to epithelial cells as a yeast, invading deper tissues by using psuedohyphae |
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saccharomyces uses |
yeast-thanol for wine yeast-carbon dioxide for leavening of bread non pathogenic |
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yeast growth compared to moulds |
yeast are capable of facultative anaerobic growth, most moulds are aerobic only |
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yeast capsules |
some yeasts produce a polysaccharide capsule ex. cryptococcus neoformans often causes meningitis in immunocompromised |
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Thermally dimorphic fungi |
two forms of growth; as a mould at lower temp. and/or yeast at body temp. |
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Thermally dimorphic fungi infectious? |
Thermally dimorphic fungi are not infectious in yeast form, mould form spreads by spore in the air |
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sporothrix- subcutaneous infection classification |
dimorphic also caled "rose garner's disease" |
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sporothrix- subcutaneous infection affect |
causes lymphangitis, inflammation of the walls of lymphatic vessels, usually in the arms or legs, causing more ulcers as disease progresses |
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fungal reproduction |
formation of spores, conidia, important for microscopic identification and or reproduction to preserve DNA very different from bacterial endospores |
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fungal vs bacterial survivability |
fungi are not picky eaters, can survive in less rich media that bacteria can. can grow better than bacteria in less than favourable conditions most are aerobic and grow best at 25-30 degrees C |
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fungal diseases are calles |
mycoses- plural mycosis- singular |
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types of mycoses |
1. superficial 2. cutaneous 3. systemic goes from less to more severe |
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superficial mycoses |
fungal infection along surface of hair shafts and outer layer of skin causes mild infecrtions ex. malessezia furfur |
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cutaneous mycoses |
fungal infection of deeper layers of the epidermis |
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cutaneous mycoses process |
deeper infection is due to dermatohytes which degarde and use keratin as carbon source (food) |
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cutaneous clinical diseases are called tineas |
capitis for head pedis for feet cruris for groin corporis for tosrso barbae for beard |
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systematic mycoses |
infections in deep tissues/ organs |
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opportunistic fungal pathogens are problematic b/c.. |
they are normally on our skin or gut |
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opportunistic fungal pathogens |
fungi are common cause of infections in immunocompromised individuals ex, aspergillosis: caused by aspergillus niger- a mold it infects people with debilitating lung diseases and immunocompromised |
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candidiasis- candida albicans |
causes vulvo-vaginal candidiasis and thrush C. albicans is normal flora in the gut and mouth |
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thursh |
are in new borns, immunocompromised and in people who have been treated with broad spectrum antibiotics |
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antiseptic |
disinfectant used on the skin |
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aseptic technique |
use of methods to exclude microorganisms |
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bactericidal |
kills bacteria |
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bacteriostatic |
inhibits growth of bacteria, doesn't kill |
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disinfectant |
chemicals used to destroy many micro-organism and viruses used for normal cleaning, lysol |
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fungicide |
kills fungi |
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pasteurization |
brief heat treatment used to reduce the numbers of organisms and to kill pathogenic organisms milk we drink is pasteurized |
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sanitization |
reduction of the # of organisms to a level that meets public health standards |
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steriliztion |
destruction of all forms of microorganisms, including spores |
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viricide |
inactivating viruses |
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ventilation and surgery |
you want clean air when doing surgery to not infect |
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how to have proper ventilation |
1. ultra-clean air with High Efficiency particulate air filters (HEPA) 2. building standards for correct air flows |
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isolation rooms with airlocks: + pressure |
air from corridor can't get into room |
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isolation rooms with airlocks: - pressure |
air from room can't get into corridor |
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physical means of controlling microbial growth |
1. heat 2. filtration 3. cold 4. high pressure 5. desiccation (drying) 6/ osmotic pressure 7. radiation |
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steriliaztion achieved by heat |
hot air 160-180 degree C for 1-2 hrs. autoclaving (moist heat) 121 degree C with 15 pounds per square inch for 15 mins. can kill C. botulinum spores (industry standard) |
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other methods to achieve sterilization |
1. irradiation (gamma or UV) 2. filtration 3. chemicals |
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complications with irradiation and filtration |
irradiation- can't penetrate too dep, not effective filtration- good for fluids, filters through viruses so that only virus needed for antivirus is needed |
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important determinant of efficiency of sterilization |
whether or not object to be sterilized is free of organic matter ie. blood, fecal material, tissue |
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spore test |
test ability of autoclaving to inactivate bacterial spores- no growth after a succesful autoclaving |
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spore test process |
ampule containing nutrient media and spores of non-pathogenic bacteria are autoclaved with object to be sterilized. then ampule is incubated to test for growth |
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spore test result determination |
growth (lack of sterilization) is indicated by a change in the pH of the ampule growth media seen as a colour change bacteria has germinated and the growing or vegetative bacteria are using nutrients in the medium and producing acid or alkali compounds that change the pH |
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negative test/ sterile- left positive test/ not sterile- right |
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chemical means of controlling growth halogens |
chlorine and iodine can sterilize if used well |
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chemical means of controlling growth aldehydes |
sterilize very well used in balming liquid; we put worms in to denature proteins ex. glutaraldehyde or cidex |
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chemical means of controlling growth ethylene oxide |
gas that sterilizes used in industry, very poisonous |
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peroxygens |
strong oxidizer, sterilizes |
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most used and useful disinfectants in everyday health care situations halogens |
iodine adn chlorine |
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iodine |
avaialbel as tincture (solution in alcohol) or as an iodaohor ( comb. of iodine and organic molecule which releases iodine slowly) eg. Betadine |
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Chlorine |
strong oxidizing agent eg. chlorox |
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alcohols |
kill bacteria and fungi but not endospores adn non-developed viruses |
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alcohol mechanism |
mechanism is protein denaturation and disruption of the liid membranes |
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degerming |
just takes away dirt on skin. we have bacteria inside our skin, injections carry the risk of hitting those bacteria and causing infection |
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isopropanol= rubbing alcohol |
better than ethanol b/c it doesn't evaporate as fast |
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optimal conc. ethanol |
70% denaturation needs water to work |
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alcohol no good? |
not good for treating wounds, as they cause a coagulation of proteins, creating an environment where the bacteria can grow inside the "scab" |
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relative resistance of microorganisms to chemical agents |
endospores, mycobacteria, cysts of vegetative protozoa, vegetative protozoa, gram negative bacteria, fungi, naked viruses, gram positive bacteria, enveloped viruses |