Lecture 7-Mmi

important as nosocomial infections and as opportunistic infection of immunocompromised

few are primary pathogens

infection that can be acquired in a hospital

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

decomposition of plant matter

edible mushrooms

leavening agent in bread

fermentation of beer/wine

stains with calcium binding agents- Calcoflour white- for rapid identification of fungi in clinical specimens

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

1. Amphotericin B

2. Azoles

3. Nystatin

1. moulds

2. yeasts

3. thermally dimorphic

mould at 20 degrees C

yeast at 37 degrees celsius

body of fungus called "thallus," masses of hyphae e.g. white powdery layer on moldy fruit

one big mold cell with multiple nuclei

individual cells

oval or spherical in shape

reproduce by budding

a line of cells that form if buds fail to detach

candida albicans may attach to epithelial cells as a yeast, invading deper tissues by using psuedohyphae

yeast-thanol for wine

yeast-carbon dioxide for leavening of bread

non pathogenic

yeast are capable of facultative anaerobic growth, most moulds are aerobic only

some yeasts produce a polysaccharide capsule

ex. cryptococcus neoformans often causes meningitis in immunocompromised

two forms of growth; as a mould at lower temp. and/or yeast at body temp.

Thermally dimorphic fungi are not infectious in yeast form, mould form spreads by spore in the air

dimorphic

also caled "rose garner's disease"

causes lymphangitis, inflammation of the walls of lymphatic vessels, usually in the arms or legs, causing more ulcers as disease progresses

formation of spores, conidia, important for microscopic identification and or reproduction

to preserve DNA

very different from bacterial endospores

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

mycoses- plural

mycosis- singular

1. superficial

2. cutaneous

3. systemic

goes from less to more severe

fungal infection along surface of hair shafts and outer layer of skin

causes mild infecrtions ex. malessezia furfur

fungal infection of deeper layers of the epidermis

deeper infection is due to dermatohytes which degarde and use keratin as carbon source (food)

capitis for head

pedis for feet

cruris for groin

corporis for tosrso

barbae for beard

infections in deep tissues/ organs

they are normally on our skin or gut

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

causes vulvo-vaginal candidiasis and thrush

C. albicans is normal flora in the gut and mouth

are in new borns, immunocompromised and in people who have been treated with broad spectrum antibiotics

disinfectant used on the skin

use of methods to exclude microorganisms

kills bacteria

inhibits growth of bacteria, doesn't kill

chemicals used to destroy many micro-organism and viruses

used for normal cleaning, lysol

kills fungi

brief heat treatment used to reduce the numbers of organisms and to kill pathogenic organisms

milk we drink is pasteurized

reduction of the # of organisms to a level that meets public health standards

destruction of all forms of microorganisms, including spores

inactivating viruses

you want clean air when doing surgery to not infect

1. ultra-clean air with High Efficiency particulate air filters (HEPA)

2. building standards for correct air flows

air from corridor can't get into room

air from room can't get into corridor

1. heat

2. filtration

3. cold

4. high pressure

5. desiccation (drying)

6/ osmotic pressure

7. radiation

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)

1. irradiation (gamma or UV)

2. filtration

3. chemicals

irradiation- can't penetrate too dep, not effective

filtration- good for fluids, filters through viruses so that only virus needed for antivirus is needed

whether or not object to be sterilized is free of organic matter ie. blood, fecal material, tissue

test ability of autoclaving to inactivate bacterial spores- no growth after a succesful autoclaving

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

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

negative test/ sterile- left

positive test/ not sterile- right

chlorine and iodine can sterilize if used well

sterilize very well

used in balming liquid; we put worms in to denature proteins

ex. glutaraldehyde or cidex

gas that sterilizes

used in industry, very poisonous

strong oxidizer, sterilizes

iodine adn chlorine

avaialbel as tincture (solution in alcohol) or as an iodaohor ( comb. of iodine and organic molecule which releases iodine slowly)

eg. Betadine

strong oxidizing agent eg. chlorox

kill bacteria and fungi but not endospores adn non-developed viruses

mechanism is protein denaturation and disruption of the liid membranes

just takes away dirt on skin. we have bacteria inside our skin, injections carry the risk of hitting those bacteria and causing infection

better than ethanol b/c it doesn't evaporate as fast

70% denaturation needs water to work

not good for treating wounds, as they cause a coagulation of proteins, creating an environment where the bacteria can grow inside the "scab"

endospores, mycobacteria, cysts of vegetative protozoa, vegetative protozoa, gram negative bacteria, fungi, naked viruses, gram positive bacteria, enveloped viruses