Microbiology Laboratory final; media, biochemical tests etc. – Flashcards
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Unlock answers| nosocomial infection |
| hospital-aquired |
| pathogenic |
| disease causing |
| opportunistic |
| does not cause diesease unless immune system is compromised |
| microorganisms are found |
| as mixed populations |
| light microscopy |
| enables examination of cell morphology |
| rod-shaped |
| bacilli |
| circular/spherical shape |
| coccus |
| streptococcus |
string of cocci
|
| staphylococcus |
| clump of coccus shaped bacteria |
| Resolution |
| how clear the image is |
| Magnification |
| how large the image is |
| total magnification |
| 10x · objective maginication |
| course adjustment use |
| 4x and 10x only |
| fine adjustment |
| 40x and 100x |
| gram positive |
color: dark purple Thick peptidoglycan layer 2 membranes polysaccharide capsule flagella: 2 support rings S-layer attached to petidoglycan if present sporulate teichoic acid/lipoids form lipoteichoic acid
|
| gram negative |
Cytoplasmic Membrane Thin peptidoglycan layer stains: light pink porins (pores) flagella (4 support rings) s-layer attached directly to outer layer do not sporulate Lipopolysaccharide outer layer |
| gram stain |
crystal violet buffer 2 stain- grams iodine decolorizer counterstain- safranin
|
| acid-fast stain |
for gram positive bacteria stain- carbol fuchsin decolorizer- acid-alcohol counterstain- methylene blue red color=acid fast; mycobacterium blue= non acid-fast; staphylococcus |
| spore stain |
gram positive spore formers- bacillus/clostridium stain- malachite green counterstain- safrain spore color- green vegetative cell- red |
| spore locations |
central- middle of cell sub-termial- near end of cell termial- end of cell |
| capsule stain |
negative stain no heat fixation stain- nigrosin; malachite green cell color- blue capsule- clear background- black Klebsiella pneumoniae |
| selective media |
| only growth of certain microorganism |
| differential media |
| distinguish one type of microorganism from another growing on the same media |
| blood agar |
type- differential and enriched streptococcus hemolysis alpha hemolysis- partial; greenish color beta hemolysis- complete; clear halo gamma hemolysis- no color change |
| MacConkey Agar |
selective for gram negative differential for- E. coli / Enterobacter test- lactose fermentation pink colonies- positive fermentation
|
| Mannitol Salt Agar |
selective- gram positive; staphylococcus phenol red indicator; pink color mannitol fermentation- yellow; S. arueus
|
| Eosin Methylene Blue agar |
selective- gram negative differential- lactose fermenters e. coli- metallic green color; positive fermentation Enterobacter- pink colonies; weak fermentation |
| Phenylethyl Alcohol agar |
| selective- gram positive |
| Methyl Red Test |
test- pyruvate fermentation media- MRVP broth indicator- methyl red; pH postive result- red color; e. coli negative result- no color change; e. aerogenes |
| Citrate test |
test- ability to transport citrate media- simmon's citrate agar; slanted in tube indicator- bromothymol blue; [in media] positive result- blue [pH inc]; e. aerogenes negative result- green; e.coli ; |
| Indole Test |
test- use of tryptophan as carbon source media- tryptone broth indicator- Kovak's reagent positive result- red layer at top of solution; e. coli negative result- no change; e. aerogenes
|
| Sulfur Indole Motility [SIM] test |
test- production of sulfide, indole production, motility media- SIM in test tube indicator- Kovaks reagent positive result- 1. black along stab=sulfide production; 2. red color=indole production; 3. black throughout=motility negative result- no red, no black |
| Nitrate Reduction Test |
test- ability to use nitrate as an electron acceptor media- nitrate broth indicator- dimethyl-alpha-napthylamine positive result- red
|
| Urease Test |
test- hyrdrolyze urea to ammonia/CO2 media- urease broth indicator- pH positive result- pink color=pH increase; p. vulgaris |
| Catalase Test |
test- ability to catalyze H2O2 into H2O/O2; differential between staph/strept media- TSA indicator- H2O2 drops on colony positive result- bubbles; staphylococcus |
| Starch Hydrolysis |
test- ability to hydrolyze starch media- starch agar indicator- gram's iodine positive result- no blue color negative result- blue color |
| Carbohydrate Fermentation |
test- ability to ferment sucrose, glucose, lactose media- phenol-red glucose/sucrose/lactose broth tubes indicator- phenol-red in media positive result- yellow color; decrease pH, gas present in durham tubes negative result- no color change |
| Terminal Death Time [TDT] |
| minimum time is the last tube with growth |
| Osmotic Stress |
| growth in the presence of different salt concentrations |
| Kirby-Bauer Method of Antibiotic Disk Diffusion |
tests for antibiotic susceptibility media- Mueller-Hinton; allows antibody to diffuse through media zone of inhibition- area around disc without growth |
| Dilution |
tube=10-x plate= 10-[x-1] |
| colony forming units |
| number of colonies;; plate dilution [10-5] |
| pGLO permeability |
CaCl2 transformation solution weakens membrane heat shock treatment causes membrane to become permeable |
| operon |
| cluster of genes under the control of a single promoter |
| endospore forming bacteria |
| Bacillus subtilis |
| parfocal |
| lens that stays in focus when magnification is changed |
