Term
| the eyepiece is the _______ lens |
|
Definition
|
|
Term
| the lenses on microscope (4 x, 10 x, 40 x) are called ____________ lens |
|
Definition
|
|
Term
| _________ is for mounting specimen |
|
Definition
|
|
Term
| _________ oil is used to minimize __________ |
|
Definition
| immersion oil, light scattering |
|
|
Term
| remove scope from cabinet using_____ and ______ |
|
Definition
|
|
Term
| use ______ adjustment knob first but do not hit the ______ lens |
|
Definition
|
|
Term
| only use _______ adjustment once you have found object |
|
Definition
|
|
Term
| what objective lens do you use oil for |
|
Definition
|
|
Term
| you use ________'s to wipe oil off the lens |
|
Definition
|
|
Term
rod shaped-
shepre shaped-
yeast |
|
Definition
rod shaped-bacilli
sphere-cocci
yeast- unicellular circles/ovals |
|
|
Term
| the method of handling microbes and materials in a way that minimizes contamination is called _______ technique |
|
Definition
|
|
Term
| the process of transferring a microbe from one medium to the next is called _______ and the sample being transferred is called an __________ |
|
Definition
|
|
Term
|
Definition
1. liquid: nutrient broth in tube (NB)
2. solid: nutrient broth+ agar (solidifying agent)(NA-nutrient agar) |
|
|
Term
| deep, slant, plate/petri dish |
|
Definition
deep- liquid straight across
slant- semi solid at a slant
petri dish- plate |
|
|
Term
| transferring an inoculum using aseptic technique |
|
Definition
-inoculate 2 NA slants from 2 NB cultures (take culture from 2 nutrient broths and inoculate them into slants)
-inoculate 1 TSB from 1 NA plate (take culture from plate and inoculate into TSB (soy broth)
-inoculate 1 NA plate from 2 broth cultures (divide plate) (take cultures from 2 broths and inoculate plate, one culture per side) |
|
|
Term
|
Definition
|
|
Term
| when do you need to sterilize |
|
Definition
-every time you open a test tube, the mouth must be sterilized
- before replacing cap, flame again
-flame loop before and after use |
|
|
Term
| the _____ is always used when transferring organisms from a liquid medium |
|
Definition
|
|
Term
|
Definition
- isolation streak plate is a method to separate individual bacteria from mixtures
-when a mixture of bacteria is streaked across a plate, the concentration of bacteria gets so low that a single bacterium can form isolated colonies on the surface of the plate
- a colony arises from a single bacterium that divides repeatedly to form a visible mass of cells |
|
|
Term
| isolation streak plate is a method used to separate individual_________ from _________ |
|
Definition
|
|
Term
|
Definition
1. flame loop, dip in inoculum, use to streak section A
2. flame loop between A and B, use streaks in section A as the inoculum for section B
3. it is not necessary to flame loop between section B and C, use streaks in section B as inoculum for section C a ^b>cv |
|
|
Term
| following incubation of streak plate you should observe |
|
Definition
| the presence of individual colonies |
|
|
Term
|
Definition
- useful for observing shape and arrangement of cells
-use only one stain |
|
|
Term
| if only the cells are stained then it is called a ________ stain, if the background is colored, leaving some or all of the cell structure unstained, then it is called _______ stain or also known as ______ stain |
|
Definition
just cells= DIRECT stain
background colored leaving some or all of cell structure unstained= NEGATIVE STAIN |
|
|
Term
| difference between direct and negative stain |
|
Definition
-direct stain directly stains cells
-negative stain colors background and leaves part or all of cell unstained |
|
|
Term
| capsule stain is an example of |
|
Definition
| negative stain (makes capsule show up, rest of slide colored) |
|
|
Term
capsule is also known as
what functions? |
|
Definition
glycocalyx
-makes cell sticky helping them attach better to surfaces
-they evade host immune system
ex: streptococcus pneumoniae, mycobacterium |
|
|
Term
| smear preparation and staining for DIRECT SIMPLE STAIN |
|
Definition
-get clean slide
-add lapful of water to slide
-obtain TINY amount of bacteria from plate using loop
- mix bacteria into drop of water and spread mixture
-let the mixture air-dry completely
-pass the slide through the flame 3 times to HEAT FIX
-cover smear with CRYSTAL VIOLET for 1 min
-rinse smear until run off it clear and blot dry
-observe using all lenses |
|
|
Term
| why do we heat fix when doing a smear and stain |
|
Definition
1: causes the cells to adhere to the slide so it wont wash off
2:Kills the microorganisms
3:Causes changes in the bacterial cells which causes them to stain better
It removes water from the bacterial cell, pores open in the cell so more stain can enter the cell wall. |
|
|
Term
| if bacterial cells aren't killed before smear what might happen |
|
Definition
| their ability to retain dye will not be as good as it would if they were dead |
|
|
Term
| what is the goal of streaking a plate? |
|
Definition
| to produce isolated individual colonies on the agar plate |
|
|
Term
| what is a bad streak plate? |
|
Definition
one that shows bad flaming after area A (too much bacteria)
improper set up |
|
|
Term
| how to inoculate a streak plate? explain and draw |
|
Definition
1. open tube of nutrient broth/organism
2. flame tube mouth
3.flame loop
4. obtain some of the organism
5.make streak in section A
6. flame loop
7. use section A as medium for section B
8. dont flame
9.use section B for section C |
|
|
Term
| what would you expect to see if you forgot to heat fix your slide? |
|
Definition
nothing, bacteria would wash off the slide if it isn't heat fixed!!
if it didn't wash off it wouldn't retain dye very well either. |
|
|
Term
| differential staining (3 types) |
|
Definition
useful for the identification of specific groups of organisms
* uses two or more stains to complete the procedue
1. gram stain
2. endospore stain
3. acid-fast stain |
|
|
Term
|
Definition
-based on the cell wall characteristics that differentiates two major groups of bacteria
-gram +(purple) and gram - (pink) |
|
|
Term
|
Definition
1.make smear
2. cover smear with crystal violet for 1 min, rinse with water
3. cover smear with iodine for 1 min, rinse with water
4. tip the slide and drip alcohol down until run off is clear (10 seconds!)
5.cover smear with safranin for 1 min
6. rinse with water and blot dry
CRYSTAL VIOLET(primary), IODINE(mordant), ALCOHOL(decolorization),SAFRANIN (counterstain/pink) |
|
|
Term
| what order do we use the dyes and alcohols for gram stain |
|
Definition
crystal violet
iodine
alcohol
safranin |
|
|
Term
the primary stain in gram staining is?
the mordant is?
the decolorization is?
the counterstain is? |
|
Definition
primary-crystal violet
iodine- mordant
alcohol- decolorization
safanin- counterstain |
|
|
Term
| differential staining (3 types) |
|
Definition
useful for the identification of specific groups of organisms
* uses two or more stains to complete the procedue
1. gram stain
2. endospore stain
3. acid-fast stain |
|
|
Term
|
Definition
-based on the cell wall characteristics that differentiates two major groups of bacteria
-gram +(purple) and gram - (pink) |
|
|
Term
|
Definition
1.make smear
2. cover smear with crystal violet for 1 min, rinse with water
3. cover smear with iodine for 1 min, rinse with water
4. tip the slide and drip alcohol down until run off is clear (10 seconds!)
5.cover smear with safranin for 1 min
6. rinse with water and blot dry
CRYSTAL VIOLET(primary), IODINE(mordant), ALCOHOL(decolorization),SAFRANIN (counterstain/pink) |
|
|
Term
| what order do we use the dyes and alcohols for gram stain |
|
Definition
crystal violet
iodine
alcohol
safranin |
|
|
Term
the primary stain in gram staining is?
the mordant is?
the decolorization is?
the counterstain is? |
|
Definition
primary-crystal violet
iodine- mordant
alcohol- decolorization
safanin- counterstain |
|
|
Term
|
Definition
clostridium and bacillus produce endospores
-endospores- a survival structure that allows the bacterial cell to survive unfavorable conditions
- under favorable conditions they germinate and release a viable vegetative cell |
|
|
Term
|
Definition
-can differentiate between acid fast- and non acid-fast bacteria
-acid fast have mycolic acid in cell walls making them waxy |
|
|
Term
| what genus can be recognized using the acid fast stain? |
|
Definition
| mycobacterium (have my colic acid) |
|
|
Term
|
Definition
eukaryotic
unicellular (yeast)
or
multicellular (molds)
mold ex: asperfillus, rhizopus, penicillium |
|
|
Term
|
Definition
eukaryotic
-divided into 4 groups based on motility:
1. use cilia (paramecium)
2.use amoeboid motion (amoeba)
3. use flagella
4. no motility
*know how paramecium and amoeba look |
|
|
Term
| fungal infections like athlete's foot are challenging to treat and often require long term courses of anti fungal drugs. why do you think fungal infections are so difficult to treat? |
|
Definition
| because both fungal and human cells are eukaryotic so this makes them have less differences that can be targeted without damaging our own cells. |
|
|
Term
|
Definition
selective media- supports growth of one group of organisms but inhibits the growth of another. usually they contain salts or dyes to inhibit the growth of the organisms not targeted for study
differential media- allows the growth of more than one microorganism of interest but with distinct differences in appearance of colonies. usually contain a specific substrate and pH indicator to serve as a differential medium.
selective and differential media- allows for only certain bacteria to grow, with a component that also differentiates among the species that survive.
enriched media- extra nutrient constituents have been provided to support the growth of fastidious microbes or encourage the growth of particular bacteria |
|
|
Term
| what media allow certain bacteria to grow, but also has component that differentiates among those bacteria that have survived |
|
Definition
| selective & differential media |
|
|
Term
| what media supports the growth of one group of organisms while inhibiting the growth of another (usually contain salts or dyes to inhibit the growth of the organisms not targeted) |
|
Definition
|
|
Term
| which media tends to use salts or dyes to inhibit growth of organisms |
|
Definition
|
|
Term
| which media allows for the growth of more than one microorganism of interest but with distinct differences in appearance of colonies (usually uses a specific substrate and pH indicator to serve as a differential medium) |
|
Definition
|
|
Term
| in differential media what is usually used as a means of differentiation |
|
Definition
| pH indicator or specific substrate |
|
|
Term
| what kind of media provides nutrients to support the growth of fastidious microbes or encourage the growth of particular bacteria |
|
Definition
|
|
Term
|
Definition
-both enriched and differential medium
-we can differentiate kinds of streptococci based on their patterns of hemolysis
-hemolysins- toxins that can break down red blood cells
-kinds of hemolysis:
1. beta hemolysis: complete breakdown of the RBC's (clearing around colonies)
2. alpha hemolysis: partial destruction of the RBCs (greenish brown color around the colonies)
3. gamma (y) hemolysis: no lysis of RBS (intact blood agar around colonies) |
|
|
Term
| blood agar is what kind of medium |
|
Definition
| enriched and differential |
|
|
Term
|
Definition
| toxins that can break down red blood cells |
|
|
Term
| how can we differentiate different kinds of streptococci? |
|
Definition
| on their patterns of hemolysis |
|
|
Term
| what are the patterns of hemolysis |
|
Definition
beta (β) hemolysis: complete breakdown of the RBCs (clearing around the colonies)
alpha (α) hemolysis: partial destruction of the RBCs (greenish brown color around the colonies)
gamma (γ) hemolysis: no lysis of RBC (intact blood agar around the colonies) |
|
|
Term
| which hemolysis causes clearing around colonies |
|
Definition
| beta hemolysis (complete breakdown of RBCS) |
|
|
Term
| which hemolysis causes greenish brown color around colonies |
|
Definition
| alpha hemolysis- partial destruction of RBC |
|
|
Term
| which hemolysis leave blood agar around colonies intact? |
|
Definition
| gamma (y) hemolysis- no lysis of RBC |
|
|
Term
| mannitol salt agar medium |
|
Definition
-selective and differential media
-shows staphylococcus pathogenic and nonpathogenic
-- selective: high concentration of salt selects salt tolerant (halophilic) satphylococcus only
-differential: mannitol fermentation differentiates pathogenic and nonpathogenic staphylococcus
- pathogenic species of staphylococcus: grow and ferment mannitol to acid- phenol red (pH indicator) changes from pink to yellow
-non pathogenic staphylococcus: grow but can't ferment mennitol-indicator stays pink |
|
|
Term
| mannitol salt sugar has what medium |
|
Definition
- selective and differential
- selective: high concentration of salt selects salt tolerant (halophilic) satphylococcus only
-differential: mannitol fermentation differentiates pathogenic and nonpathogenic staphylococcus |
|
|
Term
|
Definition
|
|
Term
staphylococcus is ___________ or has a high concentration of salt so it is selected this way against other bacteria using the mannitol salt agar (selective media)
pathogenic species of staphylococcus grow and ______ mannitol to acid which causes indicator to turn from pink to ________
nonpathogenic species of satphylococcus: grow but can't _______mannitol- indicator ________ |
|
Definition
halophilic
pathogenic-ferment manitol, change pink to yellow
nonpathogenic- grow but can't ferment manitol, indicator stays pink |
|
|
Term
| eosin methylene blue agar |
|
Definition
-selective and differential medium
-selective: dyes 1. eosin and 2.methylene blue select for gram negative bateria (including coliforms)
-differential: lactose fermentation differentiates between coliforms (lector fermentors) and noncoliforms (non lactose fermenters)
coliforms- grow and ferment lactose to acid- trigger a pink to metallic green colony coloration
-non-lactose fermenters: colonies will appear colorless
SOOO
gram positive: no growth
lactose fermenter: pink
non lactose fermenter: colorless
ecoli: metallic green (coliform) |
|
|
Term
| what differentiates between coliforms and noncoliforms? |
|
Definition
-coliforms=lactose fermentation
-non coliforms=non lactose fermenters |
|
|
Term
|
Definition
coliforms- grow and ferment lactose to acid- trigger a pink to metallic green colony coloration
-non-lactose fermenters: colonies will appear colorless |
|
|
Term
| coliforms which grow and ferment lactose to acid will trigger a _____ to ____ colony coloration on eosin methylene blue agar |
|
Definition
|
|
Term
| non lactose fermenters will appear _____ on eosin methylene blue agar |
|
Definition
|
|
Term
|
Definition
-nosocomial infections: infections acquired in a hospital setting ex: ventilator associated pneumonia (VAP)
-common causes of VAP: gram positive organisms such as streptococcus, staphylococcus, gram negative organisms including coliforms ( such as ecoli) as well as non coliforms (pseudomonas)
-media to distinguish the above scenario- a good tool to have clinically
-maconket agar: SELECTIVE AND DIFFERENTIAL MEDIUM
-selective: gram positive
-differential: coliforms, non coliforms.
selective: bile salts and crystal violet select for gram negative bacteria (including coliforms)
differential: lactose fermentation differentials between coliforms and noncoliforms (lactose fermenters- pink, non lactose fermenters: colorless) |
|
|
Term
| ecoli is gram _____ and is a _____ |
|
Definition
|
|
Term
| what selects for gram negative bacteria? |
|
Definition
| bile salts and crystal violet |
|
|
Term
|
Definition
| -identifying gram negative coliforms and noncoliforms to identify causes of nosocomial infections/ventilator associated pneumonia |
|
|
Term
|
Definition
-commonly used method to estimate the number of microbes in a sample
-originial smaple is diluted through a series of bottles/tubes
-a volume of the dilution is put onto plates and number of colonies are counted after incubation
-number of bacteria in the original sample is calculated by multiplying number of colonies on the plate by the dilution factor corresponding to that plate
-only plates containing between 30 and 300 colonies are considered to be valid and countable |
|
|
Term
| only plates containing between _ and _ colonies are considered valid and countable |
|
Definition
|
|
Term
| The presence of coliforms in food or water indicates the possibility of fecal contamination and thus the potential of fecal pathogens also being present. |
|
Definition
|
|
Term
Both MacConkey agar and EMB are useful in growing Gram positives.
true or false |
|
Definition
| false- both select for gram negative |
|
|
Term
| high concentration of ______ in mantol salt agar makes this medium selective, while the ________ makes it differential. fermentation of mantel results in the medium around the colony changing from ____ to _____ |
|
Definition
salt makes it selective
mantel makes it differential
red to yellows |
|
|
Term
| growth of ecoli on EMB (eosin methylene blue agar) would produce _________ colonies while growth on the maconkey agar would produce ______ colonies |
|
Definition
|
|
Term
| ou are testing a sample of water from a local swimming pool. Your 10-1 final dilution plate has 38 colonies on it. The safety standards from swimming pools state that the water cannot contain more than 200 CFU per milliliter [cells per milliliter]. Is the pool you are testing safe to swim in? Why or why not? |
|
Definition
| b. No, the final cell number is 380 and therefore, more than 200 CFU per milliliter. Correct |
|
|
Term
| You are testing a sample of milk from a New York dairy that has been cited for some recent safety violations. Your 10-2 final dilution plate has 201 colonies on it. The FDA safety standard for milk of the type you sampled is 3x105 per milliliter. Is this milk sample safe to drink? Why or why not? |
|
Definition
| b. Yes, the final cell number is 2.01x104 and, therefore, less than 3x105 per milliliter. Correct |
|
|
Term
|
Definition
patient A- complete clearing beta hemolysis
streptococcus pyrofens: complete clearing
pseudomonas aeruginosa: incomplete clearing alpha hemolysis
staphylococcos epidermidis: no clearning gamma hemolysis |
|
|
Term
|
Definition
sample I- colorless colonies (non lactose)
e coli- pink colonies (lactose fermenter)
pseudomonas aeruginosa: colorless colonies
staphylococcus epidermidis: no growth |
|
|
Term
| manitol salt agar results |
|
Definition
sample m- color around colony yellow (mannitol fermenter) pathogenic sp
staphylococcus aureus: color around colony yellow (mannitol fermenter) pathogenic sp
staphylococcus epidermidis- growth but no color change (non mantel fermenter) non pathogenic sp
ecoli- no growth |
|
|
Term
| eosin methylene blue results |
|
Definition
sample p: metallic green colonies (lactose fermenter)
ecoli- metallic green colonies (lactose fermenter)
pseudomonas aeruginosa: colorless colonies (nonlactose)
staphylococcus epidermidis: no growth |
|
|
Term
|
Definition
oxygen requirement of bacteria varies dramatically
a. obligate aerobe- growth at top of tube only where high oxygen concentrations have diffused into medium
b. facultative anaerobe- both aerobic and anaerobic growth but greater growth with oxygen, growth is best where the most oxygen is present at top but occurs throughout tube
c. obligate anaerobe- only anaerobic growth, ceases in presence of oxygen, growth occurs at bottom where there is no oxygen
d. aerotolerant anaerob- only anaerobic growth, but continues in presence of oxygen, growth occurs evenly and oxygen has no effect |
|
|
Term
| for what microbes does growth occur evenly, and oxygen has no effect |
|
Definition
|
|
Term
| for what microbes does growth occur most at bottom of tube |
|
Definition
| obligate anaerobes- they cannot grow where there is oxygen |
|
|
Term
| for what microbe does growth occur most at top of tube but still is present through out |
|
Definition
| facultative anaeobe- does but aerobic and anaerobic growth but greater growth in presence of oxygen |
|
|
Term
| for what microbe is growth only occurring at top of tube where oxygen is |
|
Definition
|
|
Term
| grwoth patterns in BHI adar deeps |
|
Definition
brain-heart infusion nutrient agar
tube 1: obligate aerobe: growth is only at the surface o the tube
tube 2: facultative anaerobe: uneven distribution of growth from top to bottom (more growth at top)
tube 3: aerotolerant anaerobe: uniform growth from top to bottom
tube 4: obligate anaerobe: absence of growth in the top portion of tube where oxygen is present. also not large cracks in the agar as a result of gas production by the anaerobic organism |
|
|
Term
| cracks are shown in the agar as a result of gas production by the ______ micro organism |
|
Definition
|
|
Term
|
Definition
-catalyzes hydrogen peroxide to water and oxygen
-hydrogen peroxide is toxic to the cells so many bacteria produce the enzyme catalase to break it down
- this test helps in distinguishing gram positive cocci from one another:
staphylococcus- catalase positive, white film
enterococcus- catalase negative, more clear |
|
|
Term
| oxidase (cytochrom c oxidase) |
|
Definition
-cytochrome c oxidase is the final enzyme of the electron transport chain that reduces O2 to form H2O
-purpose of this test is to determine if the bacterium of interest has cytochrom C oxidase in its electron transport chain
-this helps distinguish gram negative rods from one another |
|
|
Term
| what helps us distinguish gram positive cocci from one another? |
|
Definition
|
|
Term
| what helps us distinguish farm negative rods from one another? |
|
Definition
cytochrome c oxidase test
(aerobic organisms like pseudomonas test oxidase positve) (facultative anaerobes such as E.coli- test oxidase negative) |
|
|
Term
| what acts as final electron acceptor in anaerobic respiration |
|
Definition
| nitrate, sulfate, sulfur, and carbonate |
|
|
Term
| what acts as the final electron acceptor in fermentation |
|
Definition
| pyruvate and pyruvate derivatives |
|
|
Term
|
Definition
coal tar derivatives have been shown to cause cancer in animals but are allowed in cosmetics because they are only applied to the skin and aren't being injected into humans. coal tar colorants are listed as:
FD&C- color that can be used in food, drugs, and cosmetics
D&C- color that can be used only in drugs and cosmetics
External D&C- color that can be used in drugs and cosmetics applied to skin surface |
|
|
Term
| why is proper storage a good idea |
|
Definition
1. increased heat causes breakdown of cosmetic
2. degraded ingredients may irritate skin. |
|
|
Term
|
Definition
| will not close the pores of the skill, so it should be less likely to cause acne |
|
|
Term
|
Definition
-general purpose culture medium
-rich in nutrients |
|
|
Term
|
Definition
-red
-high salt- inhibits most bacteria (NOT staphylococci)
-mannitol- sugar alcohol- bacteria which can ferment this produce acid that causes a yellow color change in media.
-NON fermenting- red, FERMENTING- YELLOW
-staphylococcus aureus- causes infections such as acne to abscesses, toxic shock, blood poisoning. |
|
|
Term
| what is the name of the bacteria causing acnes, abscessed, toxic shock, blood poisoning which we use the __________ to test? |
|
Definition
MSA-- mannitol salt sugar
staphylococcus aureus |
|
|
Term
| staphylococci that ferment mannitol will produce a _________ color change |
|
Definition
|
|
Term
| non- mannose fermenting bacteria produce what color in the MSA plate |
|
Definition
red
(yellow if it DOES ferment mannitol) |
|
|
Term
| eosin methylene blue agar (EMB) |
|
Definition
| -contains a purple dye INHIBIITING gram positive -SUPPORTS GRAM NEGATIVE GROWTH -lactose fermenting bacteria metabolize the lactose in the media and produce acid causing a color change (GREEN for strong acid such as ecoli or PINK for weaker fermentation) |
|
|
Term
| to test for presence of fungi in producets use |
|
Definition
|
|
Term
| sabouraud dextrose agar ((SDA) |
|
Definition
- a medium used for growing fungi because the nutrients and slightly acidic environment encourages fungal growth and survival
- fungi such as yeast and molds grow |
|
|
Term
what does MSA select for
what does it differentiate |
|
Definition
staphylococci
manitol and non manitol fermenters
YELLOW if fermented
(manitol fermenters are pathogenic) staphylococcii aureus |
|
|
Term
| what does EMB select and differentiate for |
|
Definition
selects for gram -
differentiates lactose fermenters and nonlactose fermenters/coliform/noncoliform
GREEN if coliform
coliform- ecoli feca matter |
|
|
Term
| macconkey selects and differentiates for |
|
Definition
selects- gram -
differentiates:: lactose fermenters and non lactose fermenters
coliform/noncoliform
* test nosocomial infections due to hospital like ventilator associated pneumonia
RED if coliform |
|
|
Term
| what tests nosocomial infections like VAP |
|
Definition
|
|
Term
| which tube would have cracks seen due to gas production |
|
Definition
facultative anaerobe
aerotolerant anaerobe |
|
|
Term
| catalase distinguishes what |
|
Definition
gram positive cocci
h202> h20 and oxygen |
|
|
Term
| oxidase disttinguishes what |
|
Definition
|
|
Term
| does staphylococcus contain catalase |
|
Definition
|
|
Term
| does enterococcus contain catalase |
|
Definition
|
|
Term
| what is the final enzyme of ETC |
|
Definition
| oxidase (reduces O2 to H2O) |
|
|
Term
| will aerobic have oxidase |
|
Definition
|
|
Term
| what is blood agar....selective or diff |
|
Definition
|
|
Term
| pink cells with green stained structure |
|
Definition
|
|
Term
| what is the purpose of performing an isolation streak plate |
|
Definition
| to obtain a pure culture or to determine if a culture is pure |
|
|
Term
| two characteristics of a hypothesis |
|
Definition
| must be falsifiable, makes a prediction between 2 variables |
|
|
Term
| Students commonly confuse Saccharomyces cerevisiae and Staphylococcus Aureus when viewed on a microscope slide. How could you microscopically differentiate S. Cerevisiae and S. Aureus? |
|
Definition
| S. cerevisiae will be LARGER |
|
|
Term
| Considering the Gram stain technique, what would you observe if you decolorized too much? |
|
Definition
|
|
Term
|
Definition
| multiple dilution factors for all tubes (by adding exponents) |
|
|
Term
| oxidase presence causes what |
|
Definition
|
|
Term
| ecoli is a _________ ____________ |
|
Definition
|
|
Term
|
Definition
used to test sensitivity of bacteria to antibiotics
larger zone of inhibition= more effective
- measure in mm |
|
|
Term
| what are the biochemical tests |
|
Definition
-gelatin hydrolysis
- starch hydrolysis
- casein hydrolysis
- carbohydrate formation (phenol red)
- TSI
- IMViC reactions (SIM, MRVP, Simmons citrate)
- urease test
- nitrate reduction |
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Term
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Definition
- protein GELATIN is broken down by enzyme GELITINASE
- gelatin medium is semi- solid at room temp and solid when refrigerated
- inoculated with organisms, incubated at 37C, and then refrigerated
POSITIVE FOR GELITANASE- tube is runny after incubation/ refrigeration
NEGATIVE FOR GELITINASE- tube gels after inoculation and refrigeration |
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Term
| if you inoculate a gelatin medium and refrigerate it and it comes out runny what does this mean? |
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Definition
| the organism is gelatinase positive because the enzyme has broken down the gelatin |
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Term
| if you inoculate a gelatin medium and refrigerate it and it gels what does this mean? |
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Definition
| the organism is gelitinase negative because enzyme didn't break down the gelatin |
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Term
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Definition
- starch is broken down by AMYLASE enzyme
- starch agar medium is inoculated with organisms and incubated at 37C.
- the reagent iodine will then be added to test for the presence of starch, in the presence of starch iodine turns blueish-black.
POSITIVE FOR AMYLASE- agar surrounding colony does not turn bluish black after adding iodine (meaning starch is absent)
NEGATIVE FOR AMYLASE- agar surrounding the colony turns bluish black after adding iodine (starch is present meaning it wasn't broken down so it is amylase negative) |
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Term
| what breaks down starch/ hydrolyzes it |
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Definition
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Term
| what reagent is used to test for starch hydrolysis? |
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Definition
iodine
(iodine turns starch blue/black, so if it does this then amylase was not present) |
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Term
| what turns starch blue/black and what test is it used for? |
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Definition
iodine
starch hydrolysis via amylase |
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Term
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Definition
- the PROTEIN CASEIN is present in milk and is broken down by ENZYME CASEASE
- casein agar or milk agar is inoculated with organisms and incubated at 37C
CASEASE POSITIVE- clear zone surrounding colony, casein is hydrolyzed
CASEASE NEGATIVE- casein is intact, no breakdown via casease |
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Term
| what is casein and what media tests it |
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Definition
a protein present in milk
a plate with casein will test for casein hydrolysis via casease |
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Term
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Definition
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Term
| phenol red broth / carbohydrate formation |
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Definition
-phenol red broth is used to determine an organisms ability to utilize a specific sugar
- medium contains pH indicator phenol red, the sugar of interest (glucose or lactose), protein and a small inverted tube called a durham tube
- at neutral pH, the tube will appear red
- organism is inoculated in tube for 24 hrs
SUGAR MAY BE METABOLIZED BY FERMENTATION- acids are produced which when released decrease the pH and cause the phenol red to turn yellow
GAS and METABOLIZED BY FERMENTATION- acid produced, so broth is YELLOW, but gas accumulation also appears as bubble in durham tube
SUGAR CANT BE METABOLIZED BY FERMENTATION- organism will use the protein present in the medium instead, and the by product of protein metabolism such as ammonia, increases the pH and as a result the phenol red turns BRIGHT PINK
REVERSION- if tubes are incubated for too long, then reversion can occur meaning the bacteria utilized all of the carbohydrate and then start breaking down the amino acids in the medium- causes pH to increase again and phenol red will revert from yellow to red on the surface of the medium
( HALF YELLOW HALF RED) |
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Term
| if phenol red broth/ carbohydrate formation test is done and tube is bright pink with no bubbles what does this mean? |
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Definition
| carbohydrate metabolism by fermentation did not take place, the organism used the protein in medium creating a by product such as ammonia which increased the pH and resulted in a BRIGHT PINK |
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Term
| if phenol red broth/ carbohydrate formation test is done and the tube is yellow with bubbles in tube what does this mean? |
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Definition
| sugar/carbs were metabolized by fermentation but gas was also produced as a by product of fermentation!!! |
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Term
| if phenol red broth/ carb formation test is done and the tube is yellow with no bubble what does this mean? |
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Definition
| the sugar was metabolized by fermentation, acids were produced lowering the pH and turning the phenol red YELLOW |
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Term
| if phono red broth is done and the top of the tube is red while the bottom is yellow what has happened? |
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Definition
reversion
- tube was incubated too long
- bacteria utilize all carbohydrate and metabolize it via fermentation turning it YELLOW
- but then they begin to break down the amino acids in the medium also causing the pH to increase and turning the yellow phenol red BACK TO RED ON SURFACE |
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Term
| Triple sugar iron agar (TSI) |
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Definition
- a differential medium that can differentiate gram negative enteric bacteria based on the ability to FERMENT certain CARBS to produce HYDROGEN SULFIDE!!!
- the medium contains (GLUCOSE, LACTOSE and SUCROSE), a pH indicator, iron, sulfur, and protein. the concentration of glucose is much lower than the other sugars.
- the organism is stabbed and streaked on the slant and incubated for exactly 24 hrs
- at neutral pH slant will be ORANGE RED
- results recorded are color reaction of the slant, color reaction of the butt, production of gas, and production of hydrogen sulfide gas
IF SUGAR IS METABOLZED- acid is produced that decreases pH to a YELLOW
IF GAS IS PRODUCED- crack seen in agar or agar may be pushed up the tube (PRODUCED AS BY PRODUCT OF METABOLIZING CARB)
IF SUGARS ARE NOT METABOLIZED- protein in the medium may be used by organism which causes pH to increase and change color to a MEDIUM MAGENTA OR BRIGHT RED
IF HYDROGEN SULFIDE GAS PRODUCED- it reacts with iron and forms a black precipitate |
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Term
| what are the three possible results of the TSI test |
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Definition
1. sugar metabolized- acid produced, lowering pH, turns YELLOW. ***if gas is also produced CRACKS IN AGAR**
2. sugars not metabolized- protein in the medium used and pH increases turning medium MAGENTA OR BRIGHT RED
3. hydrogen sulfide gas produced- reacts with iron forming black precipitate |
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Term
| after you do the TSI test, a black precipitate has formed what does this mean? |
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Definition
| hydrogen sulfide gas was produced- iron reacts with it forming this black precipitate |
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Term
| after you do the TSI test, it is yellow and cracks are in the agar what does this mean? |
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Definition
pH was lowered meaning the sugar was metabolized through fermentation and has turned YELLOW
the cracks indicate gas production |
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Term
| after doing TSI test, the tube is bright red, what does this mean? |
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Definition
| the sugar was not metabolized, so the medium protein was used instead, raising the pH causing RED COLOR |
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Term
TSI 4 possibilities:
yellow butt and slant with gas:
yellow butt and red slant:
magenta butt and slant
magenta butt and slant with black precipitate |
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Definition
yellow but and slant with gas: glucose plus one or two sugars metabolized, gas produced, no hydrogen sulfide
yellow butt and red slant: glucose only metabolized, no gas, no hydrogen sulfide
magenta butt and slant: no sugars metabolized, proteins metabolized, no gas and no or little hydrogen sulfide
magenta butt and slant with black precipitate: no sugars metabolized, proteins metabolized, no gas, sulfide production |
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Term
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Definition
| - used to identify enteric bacteria (gram negative facultative anaerobic bacteria that reside in GI tract)
-INDOLE- indole is produced as a result of hydrolysis of tryptophan (an amino acid)
- SIM (sulfur, indole, motility) media is a combined media that contains proteins, iron and sulfur
-the sIM media is inoculated with the organism and KOVACS reagent is added after incubation.
CHERRY RED- indole positive (tryptophan hydrolysis has occurred)
NO RED- indole negative, no hydrolysis of tryptophan
- SIM media can also detect release of hydrogen sulfide gas
HYDROGEN SULFIDE PRODUCED- it reacts with iron and forms black precipitate
Methyl red (M) and Voges-Proskauer tests (V)
- all enteric organisms metabolize glucose to either acidic end products or neutral end products
- the MRVP broth medium- contains glucose and other ingredients and can differentiate organisms that generate acidic and neutral end products
- organism is inoculated into a single broth tube of MRVP. after incubation half is transferred into empty test tube so there are two tubes now.
Methyl red test (M)
- add drops of methyl red to one tube- if tube turns RED the end product is acidic (MR+)
- if TUBE STAYS YELLOW- organism has not produced an acidic end product (MR-)
voges proskaur test (V)
- add drops of VP reagents A and B to other tube
- RED/RED BROWN- organism has produced NEUTRAL end product VP+
- YELLOW/YELLOW BROWN- VP-, the organism has not produced a neutral end product
*** USUALLY MUTUALLY EXCLUSIVE- if an organism is MR+ then it is VP-
citrate test
- simmons media
- inoculated and incubated
- if medium turns BLUE- organism utilized citrate
- if medium stays green- organism did not utilize citrate |
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Term
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Definition
identifying enteric bacteria
(gram neg, facultative anaerobic bacteria in GI) |
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Term
| indole is produced as a result of |
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Definition
| hydrolysis of tryptophan (an amino acid) |
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Term
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Definition
sulfur, indole, motility
it contains proteins, iron, and sulfur |
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Term
| hydrogen sulfide in general is detected by |
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Definition
| reacting with iron and turning black precipitate |
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Term
a positive indole test would be what
a negative indole test would be
the presence of indole means what |
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Definition
SIM media turns cherry red!!!!!!!!
if negative- SIM media doesn't turn red
tryptophan hydrolysis has occurred |
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Term
| if SIM media is hydrogen sulfide positive what happens |
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Definition
| bottom of tube turns black |
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Term
| if SIM media is hydrogen sulfide negative what happens |
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Definition
bottom of tube is yellow
(DOESNT TURN BLACK!) |
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Term
| the indole test (part of IMViC) uses what medium |
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Definition
| SIMS ( sulfur, indole, motility) |
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Term
| what is added to SIM media after inoculation and incubation? |
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Definition
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Term
| what medium is kovacs reagent used for |
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Definition
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Term
| what does SIM media detect |
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Definition
indole production (hydrolysis of tryptophan)
release of hydrogen sulfide |
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Term
| the Methyl red (m) and votes proskauer tests (v) (PART OF IMViC) use what medium |
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Definition
| MRVP- which contain glucose and other ingredients and can differentiate organisms that generate acidic and neutral end products) |
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Term
| the MRVP test differentiates what |
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Definition
| enteric organisms that generate acidic or neural end products. |
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Term
| when using MRVP what tests are you doing |
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Definition
MEthyl red (M) and Voges- proskauer (V) which are part of the IMViC
testing for neutral or acidic end products |
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Term
| when using the MRVP you do what after inoculation |
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Definition
put half of tube in another test tube so you have 2 tubes
- one tube use for methyl red test, add drops of methyl red
IF IT TURNS RED- MR+ (produced acidic)
- one tube for votes proskauer test- add drops of VP reagents A and B
RED/ REDDISH BROWN- VP+ (neutral end product) |
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Term
| if during your voges proskauer test after adding ____________ reagent your tube turns RED what does this mean |
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Definition
vp+ (neutral end products)
reagent- VP REAGENTS A AND B |
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Term
| if during you methyl red test if IMViC, you add methyl red and it turns RED this means what |
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Definition
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Term
| a neutral end product turns VP test what color |
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Definition
VP+ turns tube RED or reddish brown
meaning a neutral end product was made |
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Term
| what reactions are usually mutually exclusive out of IMViC? |
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Definition
methyl red and votes proskauer
if one is positive the other is negative |
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Term
| methyl red test turning red means neutral or acidic? |
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Definition
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Term
| VP test turning RED means neutral or acidic |
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Definition
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Term
| Citrate test uses what medium |
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Definition
simmons citrate meidum
(contains citrate as sole source of carbon)
- organism inoculated and incubated
- if medium in the slant turns BLUE the citrate has been utilized
- if medium in slant STAYS GREEN- organism could not utilize citrate |
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Term
| negative citrate is what color |
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Definition
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Term
| positive citrate test is what color |
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Definition
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Term
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Definition
| urease test
-urea broth used to detect the presence of the enzyme urease, which hydrolyzes urea
- as a result of hydrolysis, ammonia is released which increases pH.
- urease is especially produced by organisms that reside in the stomach so they can survive in the acidic pH
- YELLOWISH ORANGE- stayed this color after incubation, it is NEGATIVE FOR UREASE
- BRIGHT PINK- organism is UREASE POSITIVE |
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Term
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Definition
| detecting the presence of urease WHICH IS FOUND IN ORGANISMS RESIDING IN STOMACH SO THEY CAN SURVIVE IN LOW ACIDIC pH |
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Term
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Definition
| enteric organisms ( produce it to fight acidic environment) |
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Term
| if tube stays yellowish orange after incubation in urea broth |
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Definition
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Term
| if tube turns bright pink after incubation in urea broth then |
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Definition
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Term
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Definition
- nitrate (NO3) is a nutrient that can be utilized by bacteria and reduced to nitrite (NO2) which can be further deducted to nitrogen (N2) or nitrous oxide (N2O)
- the organism is inoculated in nitrate medium and incubated to determine if nitrate reduction (formation of NO2, N2 or N2O) occurred
STEPS
1. after incubation, nitrate reagents A and B are added to the broth which can detect the presence of nitrite (NO2)
RED BROTH- nitrite is present and this is POSITIVE
CLEAR- either the broth is still NO2 or it was reduced all the way to nitrogen (N2) or nitrous oxide (N2O)( NEEDS FURTHER TESTING)
step 2: if clear, zinc is added to tube
- if any original nitrate NO3 is present, zinc will convert it to nitrite(NO2). in this scenario tube will turn RED since nitrate reagents A and B (which detect nitrite) are already present from step 1 THIS IS NEGATIVE TEST FOR NITRATE REDUCTION since the organism did not reduce nitrate on its own
- if the tube STAYS CLEAR, then no original nitrate remained, meaning this is POSITIVE FOR NITRATE REDUCTION because N2 of N2O must have been present. |
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Term
| what is nitrate reduction |
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Definition
| the formation of NO2, N2 of N2O (from nitrate NO3) |
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Term
| if you do the nitrate reduction test and get a red tube initially this means |
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Definition
| nitrate (NO3) has been reduced to nitrite (NO2) |
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Term
| if you do the nitrate test and get a clear tube this means |
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Definition
2 possibilities
1. still nitrate present, no reduction
2. nitrate has been reduced to nitrogen(N2) or nitrous oxide (N2O)
NEEDS FURTHER TESTING!!!!
ADD ZINC!!!!!
1. if zinc is added and it turns red- the zinc cause nitrate to convert to nitrite (NO2) meaning it is NEGATIVE FOR NITRATE REDUCTION since it didn't do it alone
2. if zinc is added and it stays clear, then no original nitrate was in tube meaning it was initially reduced to nitrogen or nitrous oxide so it is a POSITIVE RESULT FOR NITRATE REDUCTION |
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Term
nitrate tubes
- yellow without zinc
- clear with zinc
- red with zinc |
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Definition
yellow without zinc added- positive test, nitrate reduced to nitrite
clear with zinc- positive, nitrate reduced to nitrogen or nitrous oxide
red with zinc- negative for nitrate reduction, organism unable to reduce nitrate alone |
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Term
| what reagents are used for nitrate test |
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Definition
nitrate reagent A and B
and ZINC |
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Term
| rapid identification methods |
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Definition
multitest system- a signle unit that may run 10 or more tests at the same time
- results within 24 hours leading to an identification of the organism
ex: API20E, Minitek, Pathotec, enteropluri-test |
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Term
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Definition
allows for 15 biochemical determinations with one inoculation
- results read at 24 hours with a 5 digit code created based on the positive results
- the 5 digit code is then found on the code booklet giving you the identification of the organism |
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Term
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Definition
- method of identification of an organism or individuals DNA
- it is useful for epidemiologists to determine the source of infection and identify the organism causing a particular infection
- once the DNA is collected it is cut into small pieces using restriction endonucleases enzymes
- these enzymes cut DNA at specific sequence called the restriction site
- DNA samples with different nucleotide sequences such as samples of different bacteria will be cut differently by the same enzyme and yield different sizes of fragments |
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Term
| what is DNA fingerprint useful for |
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Definition
epidemiologists
DETERMINING SOURCE OF INFECTION AND IDENTIFYING ORGANISM CAUSING IT |
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Term
| DNA is cut into small pieces during DNA fingerprinting by what? |
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Definition
| restriction endonucleases (enzymes) |
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Term
| how are DNA fingerprinting/dna fragments examined? |
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Definition
gel electrophoresis
1. restriction enzymes cleave DNA into smaller segments of various sizes
2. DNA segments are loaded into wells in a porous gel, the gel floats in a buffer solution within a chamber between two electrodes
3. when an electric current is passed through the chamber DNA fragments move toward the positively charged cathode
4. smaller DNA segments move faster and father than larger creating the difference in appearance |
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Term
| how to do gel electrophoresis |
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Definition
- DNA samples are mixed with a loading dye and loaded into the wells of an agarose gel
- an electric field is applied across the gel causing the negatively charged DNA fragments to move from their origin (sample well) through the gel to the positive end
- the gel matrix acts as a sieve through which smaller fragements move faster than large ones
- a pattern of bands are produced fro each sample and are made visible by staining with a dye (ethidium bromide) that binds to the DNA molecule
- the bands show up under a UV lamp |
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Term
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Definition
- agglutination happens when antibodies bind to particulate antigens or cells such as bacteria and form visible climbs called agglutinates
- all diagnostic reactions use something to make antigen- antibody reactions detectable
- passive agglutination utilize beads attached to either antigen or antibodies. when the corresponding antibody or antigen from the patient sample is added clumping will be observed. |
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Term
| what does passive agglutination utilize to make antibody antigen reactions detectable |
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Definition
beads attached to either antigens or antibodies
**when the corresponding antibody or antigen from the patient sample is added, then visible clumping will be observed |
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