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131 Cards in this Set
- Front
- Back
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What do sugar fermentation tubes test for?
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tests if microorganism can ferment particular sugars
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What are the results of sugar fermentation tubes?
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Yellow= acid
Yellow + gas= acid and gas Red = negative/alkaline |
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What is a Durham Tube?
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Capsule in certain tests that tests for gas production
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What does Phenylalanie (PPA) test for?
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tests for enzyme phenylalanase (PPA and NH3)
add ferric chloride--> deep green |
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What does hydrogen sulfide production (H2S) test for?
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enzyme cyestein desulferase
--black precipitate |
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What does tryptophan (indole) test for?
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enzyme tryptophanase
--add Kovacs reagent: pos if red |
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What does the catalase test test for and how is it carried out?
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Tests for catalase enzyme which converts hydrogen peroxide to water and oxygen.
Add hydrogen peroxide to culture and look for bubbles |
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What is Endo agar differential for?
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Lactose fermentation
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What is Endo Agar selective for?
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Gram negative microorganisms
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What results from Endo Agar?
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Positive results in red colonies and surroundings
Coliforms-- gold metallic sheen |
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What is Blood Agar differential for?
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Different reactions on blood
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Gamma hemolysis?
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No clearing
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Beta hemolysis?
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Complete clearing
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Alpha hemolysis?
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Partial clearing; sometimes green
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What does Milk Agar test for?
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Caseinase
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What is the positive result of milk agar?
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Turns from white to clear around positive colonies
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What does OF Glucose test for?
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aerobic (oxidative)/ anaerobic (fermentative) growth
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How do you perform the OF Glucose test?
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Two tubes (green gelatin for gram -, purple gelatin for gram +), add oil to one and leave the other one uncovered
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Results of OF Glucose test.
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Oxidation: with oil: no change; without oil: yellow
Fermentation: yellow in both No Rxn: no change in both Ambiguous: with oil: yellow; without oil: no change |
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What does bismuth sulfide agar (BSA) test for, what's the medium color, and what are positive results?
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Tests for salmonella typhi. Medium is a dull green. And salmonella produces black growth
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What does the SIM test for?
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Sulfur, Indole, Motility
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What are the results of SIM?
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Sulfur: black
Indole: add kovacs-turns red Motility: growth away from inoculation line (cloudiness) |
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What does DNase test for and what are the results?
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Tests for exoenzyme DNase--> hydrolyzed DNA
Shows clearing |
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What is Staphylococcus 110 selective for?
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Staphylococcus: natural pigment growth
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What is in the MSA Agar?
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7.5% NaCl
Mannitol Phenol Red Indicator |
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What is Mannitol Salt Agar selective for?
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Staphylococcus
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What are the results of MSA?
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Red medium turns yellow and growth exists in positive results
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What does a lipase plate test for and what are the results?
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tests for presence of lipase enzyme
produces dark blue precipitate |
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What does IMViC stand for?
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Indol, Methyl Red, Vogues-Proskauer, Citrate
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What microorganisms does IMViC differentiate between and what are the results?
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Escherichia coli vs. Enterobacter aerogenes
Ec ++- - Ea - - ++ |
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What does the SIM test for?
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Sulfur, Indole, Motility
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What are the results of SIM?
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Sulfur: black
Indole: add kovacs-turns red Motility: growth away from inoculation line (cloudiness) |
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What does DNase test for and what are the results?
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Tests for exoenzyme DNase--> hydrolyzed DNA
Shows clearing |
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What is Staphylococcus 110 selective for?
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Staphylococcus: natural pigment growth
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What is in the MSA Agar?
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7.5% NaCl
Mannitol Phenol Red Indicator |
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What is Mannitol Salt Agar selective for?
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Staphylococcus
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What are the results of MSA?
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Red medium turns yellow and growth exists in positive results
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What does a lipase plate test for and what are the results?
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tests for presence of lipase enzyme
produces dark blue precipitate |
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What does IMViC stand for?
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Indol, Methyl Red, Vogues-Proskauer, Citrate
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What microorganisms does IMViC differentiate between and what are the results?
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Escherichia coli vs. Enterobacter aerogenes
Ec ++- - Ea - - ++ |
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What is Phenylethyl Alcohol Agar selective for?
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Selective for gram positive: shown by growth
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What is M-staphylococcus broth selective for and why?
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Selective for staphylococcus because it has a 10% NaCl concentration
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What does the motility test determine? What indicator is used?
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Determines if bacteria are motile or not (movement).
Tetrazolium chloride is red growth indicator |
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How do you carry out the coagulase test?
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Incubate plasma
--if clumpy/solid, it's positive |
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What is desoxycholate citrate selective for and what is the result?
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Selective for gram negative and lactose negative microorganisms
(lac + will be red) |
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What does SS Agar test for and what are the results?
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Tests for salmonella (black), shigella (colorless), and lactose positive (red)
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What is brilliant green agar (BGA) differential for?
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Lactose/sucrose fermentation
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What are the results of BGA test?
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Positive: yellow/green colonies and surroundings
Negative: opaque red/pink/white colonies and red surrounding |
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What does nitrate broth test for?
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Ability of microorganisms to reduce nitrate
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How is the nitrate test carried out and what are the results?
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Nitrate I and nitrate II are added: if it appears red it is positive
Add zinc in clear tubes: if it appears red, it's negative |
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What is Eosine Methylene Blue (EMB) selective and differential for?
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Selective: gram negative
Differential: Lactose (+color change, -no change) |
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What are the results of mixed acid fermentors on EMB plate?
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Dark blue/black centers
E.coli has green metallic sheen |
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What are the results of butanediol fermentors on EMB plate?
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pale pink, lavender centers
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What does the Kliger's Iron Agar (KIA) test for?
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tests for glucose/lactose fermentation, H2S, and gas
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What are the results from KIA test?
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Glucose: yellow butt
Lactose: yellow slant H2S: black precipitate Gas: cracks or lifting |
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What does litmus milk test for?
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Tests for lactose fermentation, reduction of litmus, presence of caseinase, deamination of amino acids to produce NH3
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What are the results of litmus milk test?
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acid rxn: pink liquid (pH drop)
acid curd: pink solid reduction: litmus reduced: white color alkaline rxn: blue liquid peptonization/proteolysis: clearing of medium (brown/amber color) |
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What does Voges Proskauer test for and how is it carried out?
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Tests for 2,3 butanediol fermentor (alpha-napthol intensifies color)
After VPI and VPII are added, red if positive |
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What does methyl red test for?
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Mixed acid fermentors
Color remains red |
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What does Urea test for, what is the indicator, and how can you tell if it is positive?
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enzyme urease, phenol red, red color is positive
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What does oxidase test for and what's the result?
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tests for the oxidase enzyme (through dimethyl-p-phenylenediamine hydrochloride)
changes to dark blue/black color |
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What does Simmons Citrate test for?
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Tests for ability of microorganism to utilize citrate as sole carbon source
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What are the positive results of simmons citrate?
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Media turns deep prussian blue and growth will appear
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What is desoxycholate agar (DES) selective and differential for and what are the results?
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Selective: gram negative
Differential: lactose fermentors Precipitates and red |
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What is the pH for a positive methyl red test?
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5.1
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What are the products of lipase?
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3 moles fatty acid, 1 mole of glycerol
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What does starch agar test for, how is it carried out, and what are the results?
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Tests for presence of amylase.
Iodide is added and appears blue/black Amylase is present if there is colorless areas |
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How do you differentiate salmonella from shigella
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motility, hydrogen sulfite
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What test do you add ferric chloride to get results?
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phenylalanine (PPA)
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Staph v. Strep
Types: aureus, epidermidis, saprophyticus |
Staph
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Staph v. Strep
Most penicillin resistant |
Staph
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Staph v. Strep
Microscopically: irregular clusters |
Staph
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Staph v. Strep
Found in nasal membrane, hair follicles, skin, perineum |
Staph
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Staph v. Strep
Types: pyogenes, pneumoniae, agalactiae |
Strep
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Staph v. Strep
Microscopically: chains of cocci |
Strep
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Staph v. Strep
Found in pharynx, teeth, saliva, colon, rectum, vagina |
Strep
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Streptococcus pyogenes hemolysis?
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Alpha
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Streptococcus pneumoniae hemolysis?
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Beta
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What staining technique shows shape and size?
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Simple Stain
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What staining technique uses cationic dyes?
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Simple Stain
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What dyes are methylene blue and crystal violet typically used for?
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Simple Stain
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What kind of staining process stains the background of the sample?
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Negative stain
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What are nigrosin (black anionic) and india ink (insoluble) dyes used for?
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Negative staining
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What are the three common types of endospores?
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Bacillus, clostridium, sporsarcinae
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What are the chemicals used for endospore stains (in order)?
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Malachite green
Steam Water Safranin |
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What does a positive spore test look like?
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Green
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What does a negative spore test look like?
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Pink
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Why are endospores steamed after the dye is added?
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Because they are heat/chemical resistant and the steam helps the dye penetrate through the cell wall.
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Is gram staining selective, differential, or structural?
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Differential
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What is the difference between gram positive and gram negative microorganisms?
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Gram positive have higher peptidoglycan and lower lipids
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What are the chemicals used for gram staining (in order)?
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Crystal violet
Gram's Iodine 95% ethanol Saffranin |
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What does a positive gram stain look like?
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Purple
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What does a negative gram stain look like?
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Pink
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Is acid fast staining selective, differential, or structural?
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Differential
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Is spore staining selective, differential, or structural?
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Structural
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What is the difference between acid fast positive and negative?
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Acid fast positive have higher wax content in their walls
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What two microorganisms are acid fast positive?
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mycobacterium and nocardia
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What the two types of mycobacterium?
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tuberculosis and leprae
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What are the steps of an acid fast stain (in order)?
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Calbol fuschin
Steam Acid Alcohol Methylene Blue |
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What does a positive acid fast stain look like?
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Red
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What does a negative acid fast stain look like?
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Blue
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How many lenses does a simple microscope have?
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One
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How many lenses does a compound microscope have and what are they called?
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Two: Ocular and objective
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Ocular magnification x objective magnification =
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Total magnification
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What are the three principle forms of microorganisms?
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Cocci (spherical), Bacilli (rod), and Helicoidal (spiral)
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What are the five methods of tube media preparation?
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Pour, broth, deep, slant, fermentation broth
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What is natural media?
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Media composed of complex raw materials whose actual chemical compound is unknown
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What is synthetic media?
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Media whose exact chemical compound is known and is often designed for isolation, selection, or differentiation
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What is selective media?
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Media which favors the growth of one type of microorganism over another
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What is differential media?
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Media which differentiates or distinguishes between different types of microorganisms based on differences in appearance of growth or color changes
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What are biochemical tests?
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Tests used to determine physiological characteristics or microorganisms particularly in terms of bacterial enzymes and the chemistry of biooxidation
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What chemicals are in sugar fermentation tubes?
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Glucose, lactose, mannitol, phenol red, and a durham tube
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What is a main methyl red positive microorganism?
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Escherichia
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What is the intermediate in the Voges-Proskauer reaction?
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acetyl methyl carbinol (acetoin)
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What is used in the Voges-Proskauer test to intensify the brick red color?
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Alpha naphthol
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What is a main voges-proskauer positive microorganism?
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Eneterobacter
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What does the enzyme oxidase oxidize?
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Aromatic amines
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What is Kovac's reagent?
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p-dimethylaminobenzaldehyde, amyl or butyl alcohol, and HCl
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What is a main microorganism that is positive for urease and H2S?
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Proteus
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In the Urease test, what does the pH have to be for the indicator to appear red?
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8.1
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What is the indicator for OF Glucose?
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Brom Thymol Blue
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Coliform type
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Rod-shaped, gram negative, non-spore forming organisms that ferment lactose with the production of acid and gas when incubated.
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What species of Staphylococcus can coagulate plasma?
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Staphylococcus aureus
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What two main pathogens have the ability to cause enteric fevers, food poisoning, dysentery, and typhoid fever?
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Salmonella and Shigella
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How do you perform a standard plate count?
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Dilute the culture sample and growing the bacteria up on nutrient agar. Then count the number of colonies that grow on the nutrient agar to determine the number of bacteria in the diluted sample.
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Number of organisms per mL in direct microscopic count?
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(Average number of bacteria/field of view)(Microscopic factor)(1/dilution factor)
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Microscopic factor in direct microscopic count?
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Area of film(area of indention in breed slide)/Area of microscopic field (πr2)
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Two microorganisms that are coliforms
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Eschericia coli and Enterobacter aerogenes
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Presumptive test
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Series of 9-12 tubes of lactose broth used to identify if there are any bacteria in the water that are lactose fermenting gas producing.
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Confirmed test
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EMB or Endo Agar plates are inoculated from gas positive lactose broths. On EMB- form small colonies with dark centers. On Endo- reddish colonies.
Both- metallic sheen |
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Completed test
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Lactose positive gram negative colonies are selected and inoculated into lactose broth and onto nutrient agar slants. Gas and gram negative rods=coliform.
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