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Infectious diseases > LAB EXAM #1 > Flashcards

LAB EXAM #1 Flashcards

1
Q

Why is it important for pathogen and toxin use in Canada to be federally regulated?

A

Reduce accidents, increase saftey.

Ensure proceedure and standard protocall is the same accross Canada.

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2
Q

What are RG2 organisms?

A

Moderate risk to individuals, low risk to public health.

Capable of causeubg serious disease but unlikely due to effective medication and preventable measures along with low spread risk.

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3
Q

What is the difference between RG1,2,3,4?

A

RG1- will not cause disease in healthy individual
RG2- Can cause disease, treatable and preventable
RG3- Will cause serious disease, may not be treatable or preventable
RG4- Will cause death, hugfhly cointageious, not preventable or treatable

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4
Q

What is a containment zone?

A

An area that is up to standard for specific conainmengt level.

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5
Q

What are the 4 pillars of engineering saftey?

A
  1. Engineering control- physical saftey controls related to lab, ex. Closed and locked doors
  2. Administrative control- behind the scenes control administarted by camosun biological saftey officer.
  3. Standardized oporating proceedure- following proceedure wnen entering or exiting lab.
  4. Personal protective equitment- lab coats
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6
Q

What is SOP for entering lab?

A
  1. Place bags and belongings away
  2. Put on lab coat
  3. Disinfect table/surfaces
  4. Wash hands
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7
Q

What is POS for exiting lab after working with RG2 organisms?

A
  1. Remove gloves - autovlave
  2. Wash hands - garbage
  3. Sanatize work bench - garbage
  4. Take off lab coat
  5. Wash hands - harbage
  6. Grab belongings
  7. Exit lab
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8
Q

How does soap work?

A

Squeezes itself between oil molecules on your skin, (microorganims and viruses/pions adhear to these oils) then removes oils and dirt.

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9
Q

How do you use a microscope?

A
  1. Carry holding base and neck
  2. Plug in and turn on light source
  3. Lower course focus knob, and place revolving nosepiece to lowest objective (10x)
  4. Place specimine securly in specimine holder.
  5. Using condenser knob, lift condeser a paper thickness away from up-most possition
  6. Raise stage all the way till it stops uging course focus knob
  7. Look through oclar lenses and lower stage untill specimine is clear
  8. Focus on specimine using fine focus lense
  9. Begin increaseing objective and continue adjusting with fine focus knob
  10. When reacges 100x objective (oil immursion lense) turn objectives on an angle, place drop of oil directly on specamine, allow 100x objective to touch oil but not slide. Use kim whip to clean both slide and lense.
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10
Q

What are the differet types of stains?

A
  1. Simple stain - stains everything the same colour
  2. Structural stain - used to identify specific parts of microorganisms ex. Campsules or spores
  3. Differential stain - uses multiple reagents cuaseing bacterial cells/structures to stain differently.
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11
Q

How does the Modified Gin’s Capsul stain/Negative stain work?

A

Used when staining bacteriacl capsules or glycocalyx because of the gelatenous, non-ionic layer sourounding the bacterial cell, the stain will not stick, staining everythig includidng the backround, leaving the structure of interest unstained. (A counter stain can be used however.)

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12
Q

How does a GM stain work?

A

Gm+ bacterial cells are surrounded by a thick peptidoglycan layer and teichoic acid, meaning first stained used will dye the cells.
Gm- bacterial cells are surropunded by a thin peptidoglycan layer and then an outter layer (LPS) that will stain only after the second stain is used.

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13
Q

What are the 4 steps to performing a GM stain?

A
  1. Primary stain (Crystal violet) - posatvily charges cationic dye, stains all cells pruple.
  2. Mordant (grams’ Iodine) - crystal violet and iodine combine forming an insouluble complex (Cyrstal violet- iodine complex)
  3. Decoulorizer (Acetone- alcohol) - deteriates GM- outter layer removing stain, dehidrates and sets in GM+ purple stain.
  4. Countrer stain (Safranin) - stains colourless GM- peptidoglycan layer pink.
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14
Q

How do you make a smear from broth culture?

A
  1. Mix culture well
  2. Use a greased pencil to draw cirlcles on a slide, then using a sterile innoculating loop to stransfer multiple loop-fulls into the circle and spread
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15
Q

How do you make a smear from a colonly growing on a solid media?

A
  1. Draw with greased pencil, place steril water inside.

2. Using steril loop obtain small amounyt of culture to water and mix.

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16
Q

What is the purpose of heat fixing / fixation?

A

fixation kills bacteria, perserves morpholgy and adhears cells to the slide.

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17
Q

What does it mean if a bacteria passes teh string test? Whats happening?

A

With Gm- bacteria, the KOH dissolves the outer layer (LPS) exposing the bacteria cell’s DNA which attaches to the loop. GM+ has too think of a layer for the KOH to reach the DNA

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18
Q

What is sub-culturing?

A

Aseptically handling bateria and moving it from one grown media to another.

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19
Q

What guidlines showuld always be followed when working w/ bacteria transfer aseptically?

A
  1. Work close to a flame (rising hot air protects cultures and media from airborn contamination (microorganisms)
  2. Never place culture caps, lids or tubes of work benches
  3. Angle petri dish lid to form a barrier between culture abd the air above.
  4. Avoid talking and work quickly
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20
Q

What is biofilm?

A

Matrix-encloused bacterial population adhearing to eachother and or surfaces

21
Q

What is pureculture?

A

A culture conatining organisms desended froma single bacterial cell.

22
Q

What is the streak plate method for isolating colonies?

A

A way to obtain isolated cultures and pur culture bacterial sample by first using a steril loop to obtain a large quantity of culture and placing it 1/4 of the media. Sterilize, collect small sample from placed culture spread 1/4, continue untill 4/4.

After incubating visual colonies daughter cells should be present.

23
Q

What are two different ways to preform a spread plate?

A
  1. When speading a known volume, micropipetter and hockey stick
  2. Sterile swab when volume dosent matter
24
Q

What diffenec does dilutig cultures make?

A

If dilutes, it is easier to obtain single cells along the spread plate allowing single colonies to grow.

If dense, confluent growth will occure (lawn)

25
Q

What is streaking for growth?

A

Testing to see if multiple types of bacteria are abel to grow on a certain plate, not alot of bateria is needed on the plate, simple zig zag motion on 1/4 of plate is perfect.

26
Q

When preparing plates what is the pourpose of flaming the loop before, inbetween and after for isolating colonies?

A
  1. to sterilize loop ensuring to not introduce foreign bateria to culture broth and plate
  2. Remove excess bacteria to ensure obtainment of single cells —-> single colonies
  3. Sterilize ensureing bateria dosent grow on loop.
27
Q

What is the different between antisepics and disinfectants?

A

Antiseptics - chemical agents that are safe to apply to skin and live tissues
Disinfectants - cghemical agents that are garmful to skin/living tissues, used to kill all bacteria and prevent new growth

28
Q

What factors effect which antimicrobial agent is most sutable?

A

Number and types of microorganisms, environmental conditions (Temp, pH), presence of extraneous matter, time, toxicity, corrosive propertioes and cost

29
Q

What is the phenol coeficent?

A

Test that compares the effectivness of a given product by compared to the killig power of phenol under same conditions.

30
Q

What is the use-dilution method?

A

Establishes the appropreate dlution for use.

31
Q

What are the uncontrolled variables of zone-of-inhabition?

A
  1. Amount of product absorbed
  2. Solubitly in water
  3. Rate of diffusion
32
Q

What are chemotheraputic antimicrobial agents and what are their 3 catagories?

A

Chemicals taken internally to reduce disease.

  1. Antibiotics - Native products of microorganisms active againts other microorganisms
  2. Semi-synthetic - microbially produced, then aultered in lab
  3. Synthetic - produced entierly in the lab
33
Q

What is the Kirby-Bauer Disk Diffusion Method?

A

Standardized disk test, simular to the zone-of-inhibition, involves growing pure cultures in a specific broth to a standardized tubidity.

34
Q

What is Basal Media?

A

An all-purpous media designed to provide neutrients nessecary to support growth for most microbes. Can be ENRICHED by adding ingrediants providing extra neutriants, ex. Blood

35
Q

What is Selective Media?

A

Used to promote the growth or specific bacteria and inhibit the growth of other bacteria. When a specific medium is added to acheive groteh pf desired microbes we call this SELECTIVE MEDIUM

36
Q

Differetial Media?

A

Ingrediants incorperated cause certain organisms to develope an appearance different from other microbs allowing us to differentiate them due to chemical changes.

37
Q

Whar are the qualities of Blood Agar?

A

Used to determine if bacterial colonu producezes the enzyme hemolysin which breaks down red blood cells. Also differentiates what type of hemolysin it is.

  1. Beta - fully breaks down RBC, appears clear or white around bacteria
  2. Alpha - partially breaks down RBC, appears brown or green
  3. Gamma - Dosent break down RBC, no change
38
Q

What is MacConkey agar (MAC)

A

Selectrive and differential medium coIntaining bile salts that inhibit the growth of non-enteric (Intestional) organisms, along with a small amount of crystal violet which inhibits the groth of GM+ microbs lactose. If bacteria grows, we know it is enteric, and if and if it is able to ferment the lactose which acts as a carbohydrate (Food to bacteria) it will result in hot magenta colour and if not a pale pink colour. When lactose is fermented there is a drop in pH.

39
Q

What is Mannitol Salt Agar (MSA)?

A

Selective and differential agar that contains high levels of Sodium (7.5%) that inhibits the growth of most microbes except for staohylococcui, also contains mannitol and pH indicator. If growth occurs we know it is some form of Staphyococci. However only Staph. Aureus is able to ferment mannitol and therefor will appear yellow shpowing us that it is present.

40
Q

Are Gm+ or GM- Bacteria easier to control with antimicrobial chemicals, why?

A

Gm+ because it dosent contain an outer lipid membrane that protects it.

41
Q

What factors should be considered when determining the appropreiate antibiotic to use?

A

Other medications being taken, alergies, toxicity, sideffects amnd dosage amount.

42
Q

What cultures and plates are used for Lab #2,3 and 4?

A 
#2- Staphylococcus empidermis, halfnia alvei, escherichia coli and bacillus subtilis
#3- broth of yeast and broth of escherichia coli. Plates, YPD (Yeast extract peptone aextrose) and NA (Nutrient agar)
#4 - staphylococcus epidermidis, escherichia coli (Staphylococus aureus RG2 + Hafnia alvei 4.3) muller-hinton agar plate (4.1), TSA plate(4.2), BAP, MAC and MSA (4.3)
43
Q

For Lab #4, 4.3 what plates are used and which cultures are used for EACH plate?

A

BAP - S. aureus, E. coli, S. Epidermidis
MAC - E. coli, S. aureus, H. alvie
MSA - S. aureus, S. Epidermidis, E. coli

44
Q

What happens in Lab 2?

A
  1. 1 - Grams stain

2. 2 - String test

45
Q

What happens in Lab #3?

A
  1. 1- streak plate to isolate colonie
  2. 2 - two types of spread plates
  3. 3 - strak plate growth
46
Q

What happens in Lab #4?

A
  1. 1 - Kirby-bauer test
  2. 2 - disinfectants vs anticeptics
  3. 3 - selective vs differntial media
47
Q

What is Parfocal?

A

When the specimen remains semi-focused even when switching objectives

48
Q

What is the field of view?

A

He area you see when looking through a microscope. As magnification increases, feild of view decreases.

Infectious diseases (3 decks)

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