Lab Practical Review – Flashcards
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| Temperature & Growth |
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| Minimum, Optimum, Maximum |
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| Optimum 5oC |
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| Psychrophiles |
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| Optimum 37oC |
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| Mesophiles |
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| Optimum 60oC |
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| Thermophiles |
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| pH Groups |
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| ?Acidophiles < 6.0 ?Neutrophiles 6.5 - 7.5 ?Alkylophiles (basophiles) >7.0 |
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| Oxidation-Reduction Potential (requirements or tolerance) |
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| ?Strictly Aerobic: requires O2 ?Facultative: Can live w/o O2 but prefers it (E. coli) ?Strictly Anaerobic: Fermentation only - does not like O2 |
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| Osmotic Pressure - Salt Concentration |
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| ?Halophiles: Require higher salt to survive & grow ?Halotolerant: do not require higher salt but can tolerate it ?Non-Halophile: grow best with only 0.5% salt; use other solutes to bind water ?Osmophile: tolerates osmotic pressure when other solutes (not salt) are high in concentration |
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| UV Resistant |
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| can absorb UV & correct damage |
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| UV Sensitive (lethal) |
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| Cannot tolerate or correct damage from UV rays |
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| What bacteria is Urease (+)? |
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| Proteus |
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| Exoenzymes |
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| enzymes from the outside that can cause a reaction to bacteria |
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| Mixed Acid Fermentor (very strong acid production) |
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| E. coli |
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| Only media that selects Gram (+) |
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| PEA |
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| Tryptophan (Indole) Tube |
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| Tryptophanase produces Indole + pyruvic acid + NH3 The trytone in the broth is reduced and turns cerise ? The Red Kovac was trippin’ with acid and spent alldol monee (indoleammonie) |
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| Negative Staining |
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| Anionic dye & negative cell - stains background around cell |
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| Gram Stain (+) |
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| Purple (no LPS & thick peptidoglycan) from Crystal Violet |
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| Gram Stain (-) |
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| Pink (thin peptidoglycan) from Safranin |
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| Gram's Iodine |
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| Mordant |
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| Acid Fast |
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| Pink (+) because of mycolic wax in cell wall (mycobacteria, clostridium) |
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| Spore Staining (+) |
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| Green Endospores or Free Spores and Pink vegetative cells (clostridium, bacillus) |
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| DES (Desoxycholate) |
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| Selects for Gram (-), Differential for Lac (+) ferm; reaction is red organisms pulling dye from media ? desoxychocolate and strawberries |
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| EMB (Eosin Methylene Blue) |
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| Selects for Gram (-), Differential for Lac (+) ferm; reaction is either Eosin (pink/purple) or Methylene Blue (dark blue/black) organisms pulling dye from media **Ea pulls Eosin, Ec pulls dark blue because strong acid fermentor. Ec also creates green metallic sheen |
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| Blood Agar |
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| Differentiates organisms based on reactions to blood ? Alpha hemolysis: partial clearing ? Beta hemolysis: complete clearing ? Gamma hemolysis: no clearing **Staph is Beta and Strep is both Alpha and Beta |
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| Starch Agar |
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| Amylase hydrolyzes starch to sugars; iodine added: clear (+), brown/purple (-) **Bacillus cereus ? Amy cleared it out of the starch (park) – my back swing is serious ? Amy wants to clear diet of starch |
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| Milk Agar |
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| Caseinase hydrolyzes casein into amino acids --> clear ? I’m casing the milk joint till it’s clear ? I cleared my milk shake case |
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| Lipase Agar |
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| lipase hydrolyzes fat to glycerol & fatty acids; organism pulls in blue dye from medium ? Lippy the fat blue whale |
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| Phenol Red (Sugar Ferm Tubes) - pink liquid |
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| Alkaline reaction ? alki’s like pepto bismal |
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| Phenol Red (Sugar Ferm Tubes) - yellow liquid |
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| Acid reaction |
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| Phenol Red (Sugar Ferm Tubes) - yellow & gas bubble |
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| Acid & Gas reaction ? acidic lemons give me gas |
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| Phenol Red (Sugar Ferm Tubes) - No color change - stays red |
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| Neutral reaction ? neutrals are angry red |
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| MR-VP Tubes (Methyl Red) |
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| Mixed Acid Fermentor (+) = Red liquid **E. coli is strong mixed acid fermentor ? E.coli has best acid party mix because he’s in the red district |
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| MR-VP Tubes (Voges-Proskauer) |
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| 2,3 butanediol ferments acid close to neutral with red color after VP I (alpha napthol) & VP II (KOH) ? VP has neutral nappy red butt when KOH’d |
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| Catalase Tube |
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| Catalase converts H2O2 to H2O & O2 --> addition of H2O2 creates bubbles ? The cat likes bubbles |
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| Oxidase Tube |
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| Oxidase Cytochrome C oxidizes aromatic amines to colored products - dark blue-black ? Oxidase purple haze |
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| Nitrate Tube |
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| Nitrate Reduction after N I (sulfanilic acid) and N II (dimethyl-alpha-napthylamine) = red color (+) If clear, add Zinc = stays clear (+); changes to red (-) ? Blemishes are red and Zinc keeps it clear |
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| Urea |
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| Urease converts urea to NH3 & CO2; color is cerise **Proteus vulgaris ? Urease is Cerise for Proteese |
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| SIM stab |
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| Sulfur, Indole & Motility Black (+), cloudiness throughout tube (+), Red after Kovacs (+) **Proteus & Salmonella have same results ? She stabbed his black sulfur heart, Kovac’s money is indee red (remember crazy acid party), clouds are motile |
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| Simmons Citrate |
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| Citrate as sole carbon source - growth on green or blue color ? Carbon grows in the green grass or deep blue sea |
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| Phenylalanine/PPA |
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| Phenylalanase converts phenylalanine to PPA & NH3 & turns green after Ferric Chloride ? Phyllis the ferret likes green apples |
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| Litmus Milk Tubes - Pink Liquid |
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| Acid Reaction from Lactose Ferm ? Best acid is found in the red district |
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| Litmus Milk Tubes - Pink Solid |
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| Acid Curd Reaction or Acid Curd Reduction ? Don’t eat the red milk curd – it’s laced with acid |
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| Litmus Milk Tubes - Colorless & white |
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| Reduction - litmus reduced ? Reduced milk is watery |
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| Litmus Milk Tubes - Blue/purple liquid |
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| Alkaline reaction ? Alki’s are blue w/o alcohol |
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| Litmus Milk Tubes - Clearing of medium (brown/amber) |
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| Peptonization/Proteolysis ? Pepto lysis clears the brown |
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| IMViC |
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| **Best test for differentiation of Fecal (Ec) vs. Non-Fecal (Ea) Indole, Methyl Red, Voges-Proskauer, Citrate Ec + for first two and - for second two tests; Ea opposite ? I M optimist (E. coli is ++) ? I M pessimist (Enterobacter is --) |
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| Kliger's Iron Agar (KIA) - all red |
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| Negative for Glu, Lac & H2S |
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| Kliger's Iron Agar (KIA) - red top, yellow bottom |
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| Glu (+) |
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| Kliger's Iron Agar (KIA) - Yellow throughout |
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| Glu (+) & Lac (+) |
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| Kliger's Iron Agar (KIA) - red top, black in middle, yellow butt |
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| Glu (+) & H2S (+) ? Gassy Klingon’s have clear or black butts |
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| Kliger's Iron Agar (KIA) - yellow top & butt, black in middle, |
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| Glu (+), Lac (+), H2S (+) |
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| OF Glucose - Open & Closed Green/Purple |
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| Strictly Oxidative (aerobic) |
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| OF Glucose - Open & Closed Yellow |
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| Fermentative (anaerobic) |
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| OF Glucose - Yellow at top only – Mainly Green/Purple |
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| Incomplete Oxidative |
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| OF Glucose - Green/Purple Open, and only Closed Yellow |
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| Facultative, NOT Ferm |
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| BSA |
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| Selects for Salmonella – dull green with black or dark brown colonies |
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| BGA |
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| Selective for Gram (-), Differential for Lactose (+) & (-) |
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| SS Agar |
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| Selective mostly for Salmonella & Shigella, Differential for Lactose (+) & (-) |
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| EMB (Eosin Methylene Blue) |
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| ? Ec takes up MB (Methylene blue): Blue w/ green sheen (more gas) ? Ea takes up E (Eosin): Purple-pink (less gas) ? Color changes based on amount of acidic gas produced |
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| Coagulase |
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| Clumpy (+); Only valid for Staph Gram (+) |
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| MSA (Phenol Red & Manitol Salt Agar) |
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| 7.5% NaCl, Selective for Staph (prefers salt); Inhibits other bacteria that are not salt tolerant ? Halophiles will change red to yellow (Staph) |
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| Staphylococcus 110 Medium |
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| 7.5% NaCl but no Phenol Red, Selective for Staph No color change, just natural colony pigment formation |
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| DNase |
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| Blue green plate has clearing with (+) growth (w/ or w/o Hcl) Tests for exoenzymes to hydrolyze DNA |
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| M-Staphylococcus broth |
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| 10% NaCl, Selective for Staph (prefers salt); Inhibits other bacteria |
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| Endo Agar |
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| Selects for Gram (-), differential for Lactose (+) ? Ec has golden metallic sheen (more gas) ? Ea has Purple-pink (less gas) ? Color changes based on amount of acidic gas produced ? Lactose (+) = red colonies |
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| BHI (Brain Heart Infusion) |
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| Differential for Staph (+) & Strep (-) ? Add H2O2 for + Catalase reaction |
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| Water Analysis - Presumptive Test |
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| Analysis used for Enterics - Intestinal Bacteria (Gram (-) and can be coccobacillus) Look for Acid & Gas = Lac (+) Ferm |
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| Water Analysis - Confirmed Test |
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| Streak Presump (+) & streak on EMB & Endo plates; Look for coliforms – fecal vs. non-fecal |
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| Water Analysis - Completed Test |
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| Use the colonies from the (+) test and inoculate on Lac to confirm ? Lac broth & slant: if gas in tube, Lac (+) Lactose is very strong acid producer (glucose not as much) |
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| Coliform Fecal |
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| E. coli Lac (+) & only in colon |
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| Non-Fecal |
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| Ea Lac (-) and just intestines |
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| Test used to differentiate between E. coli and E. aerogenes |
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| IMViC Ec is (+) for first two and (-) for second two Ea is (-) for first two and (+) for second two |
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| MFM (Membrane Filter Method) |
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| Bacteria 1.0 micron so filters used 0.45 micron (sometimes .22) |
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| Filter used for MFM |
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| M-FC: membrane fecal coliform |
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| Temp M-FC incubated at |
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| 44.5oC ? E. coli can be isolated because tolerates 45-46 oC ? Ea is inhibited because tolerates only up to 44 oC |
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| Advantages of MFM test w/ M-FC |
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| ? Temp allows for only Fecal coliform count (no non-fecal) ? Test larger samples of water |
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| MPN |
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| Most Probable Number use the table to determine the range of colonies of coliforms ? Compare numbers for 10ml, 1ml & .01ml & match to table to determine MPN ranges |
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| MIC |
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| Minimum Inhibitory Concentration how little of the stuff you can use that is effective w/o minimal side effects |
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| Disinfectants |
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| Strong Chemicals for inanimate objects): ? Formaldehyde (most effective) ? Phenol (not very effective) **Does not sterilize but can eliminate some infectious agents |
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| Antiseptics |
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| mild chemicals that reduce # of microbes ? Iodine – aseptic |
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| Antibiotics |
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| ? chemicals that interfere with microbial cell function ? cmeasure zone of inhibition in mm & compare to Kirby-Bauer table |
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| Formaldehyde |
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| most effective disinfectant |
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| Phenol |
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| Not very effective disinfectant |
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| Iodine |
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| Aseptic antiseptic - medium effectivity |
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| Kirby-Bauer Table |
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| Table that is used to determine the category of antibiotic |
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| Antibiotic Categories |
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| o Resistant (<#) o Intermediate (range) o Sensitive (>#) |
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| Plate used for antibiotic effectiveness |
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| MH Plate - Mueller Hinton plate and always used for KB test |
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| Gram Stain Procedures |
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| ? Smear prep & heat fix ? Crystal violet for 1 minute, rinse with water ? Iodine for 1 minute (mordant), rinse ? Decolorize with Ethyl Alcohol 10-15 sec, rinse ? counterstain with safranin, rinse |
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| Acid Fast Procedures |
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| ? Smear prep & heat fix ? Carbolfuschin while steaming for 10 min ? rinse with acid alcohol ? counterstain with methylene blue ? rinse with water |
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| Spore Stain Procedures |
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| ? Smear prep & heat fix ? Malachite Green while steaming for 10 min ? rinse with water ? counterstain with safranin ? rinse with water |
