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| enterics |
-ferment glucose only under anaerobic conditions |
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mcs5109 Tue, 29 Apr 2008 22:47:19 GMT |
 |
| Denitrification Detection |
-selects N2 gas-producing heterotrophs
-nitrate broth has C for C and E source
-nitrate serves as t.e-.a.
-N gas collected in Durham tube
-if bubble, + for denitrification |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| Nitrate |
-branch pt b/w recycling N within the soil or returning it to gaseous form
-used by plants, die, ammonifiied, |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| Denitrification |
-formation of N gas from nitrates
-soil bacteria causes this to occur
-nitrate--> nitrite--> N2O --> N2
-NO3 can serve as t.e-.a. in anaerobic conditions
-final end product (N2O or N2) depends on pH of environment
-must add fertilizer to replenish nitrates! |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| detection of nitrate |
-broth contains only NO2-
-nitrate detected by diphenylamine reagent to form blue/black color
-make sure all nitrite is removed! |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| detection of nitrification |
-use NH4+ to NO2-
-use broth with NH4+ as sole N source
-has to use NH4+ as E and CO2 as C sources
-Trommsdorf reagent w/ H2SO4
-rxs w/ nitrite to form blue-back color
-blue/black = + for nitrite |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
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| assimilatory nitrate reduction |
-once in plant cell, nitrates reduced to ammonium and incorporated into aa's
-soil doesn't hold to negatively charged NO3 well |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| NItrobacter |
-oxidizes nitrite to nitrate |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| Nitrosomonas |
-oxidize ammonium ions to nitrite |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| Nitrification |
-NH4 converted to NO2 then to NO3
-aerobic conditions
-NO3 principle source of N for protein synthesis in plants
-chemoautotrophic (use CO2 as C source and NH3 for E source)
-increases nitrate in soil |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| Nessler's reagent |
-K2HgI4
-yellow= + for ammoniafication |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| detection of ammoniafication |
-peptone-rich broth
-amino groups released as NH3
-NH3 detected by Nessler's reagent |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| ammoniafication |
-also N fixation
-animal wastes and carcasses decomposed by soil microbes to produce aa's
-converted into ammonia then ammonium (NH4+)
-affected by wide spectrum of bacteria and fungi
-NH4+ can be re-released into plants/ other microorganisms
-becomes substrate for nitrifying bacteria |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| bacteroids |
-irregular shapes
-Y-, T-, and club-shaped |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| to ID Rhizobium |
-roots/nodules crushed and stained
-outside nodules, rod-shaped
-inside nodules, bacteroids form |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
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| excess ammonium |
-synthesize aa's
-deposited into soil to fertilize other plants |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
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| Rhizobium |
-close association w/ roots (usually legumes)
-plants provides anaerobic environment and nutrients from photosynthesis
-Rhizobium fixes N for plant
-form root nodules packed w/ bacteria
-ammonium incorporated into aa's and proteins |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| Azotobacter cells |
-ovoid rods
-cysts
-selected using mannitol salts broth w/ no N source (can only grow if it can fix atmospheric N)
-all other N-fixing bacteria require more than just mannitol as E and C source |
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mcs5109 Sat, 26 Apr 2008 20:22:15 GMT |
|
| Nonsymbiotic N fixing microbes |
-reside in soil
-Azotobacter/Azotospirillum (aerobic)
-Clostridium (anaerobic)
-all fix relatively little N and limited by E available to them |
1 |
mcs5109 Sat, 26 Apr 2008 19:25:45 GMT |
|
| cyanobacteria |
-free-living
-photosynthetic
-fix most N in aquatic environment |
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mcs5109 Sat, 26 Apr 2008 05:28:42 GMT |
|
| N fixation |
-microbial process where N gas is converted into ammonia (NH3/NH4+) and rapidly assimilated into organic molecules
-reverses denitrification
-include symbiotic and non-symbiotic |
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mcs5109 Sat, 26 Apr 2008 05:28:42 GMT |
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| N |
-80% of atmosphere |
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mcs5109 Sat, 26 Apr 2008 05:28:42 GMT |
|
| cycle |
-10-fold range change on semilog paper |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
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| yogurt |
-produced from milk w/ 25% water removed
-add 1:1 ratio Streptococus thermophilis (grows faster, primary producer of acid) and Lactobacillus balgaricus (flavor and aroma)
-# microbes drops after a few weeks
-beneficial bacteria
-inhibits undesired organisms (ex: E. coli disappears after 3 days)
-anti-cancer effects? |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
|
| fermenting milk products |
-extends shelf life
-creates new products/flavors
-lactic acid maintains protective gut flora
-produce vitamins absorbed into body |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
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| homolactic |
-lactic acid primary byproduct
-not only byproduct
-variations in metabolic pathways produce different dairy products |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
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| heterolactic species |
-lactic acid produced, but not the primary byproduct
-not as useful as homolactic
-may have = or > amounts CO2, ethanol, acetic acid, organic acids |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
|
| fermented milk |
-produce lactic acid as fermentation byproduct--> homolactic or homofermentative species
-used in lactic starter cultures to produce butter, cultured buttermilk, other fermented milks, cultured sour cream, yogurt, cottage cheese |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
|
| starter cultures |
-ferment milk and create greater shelf life
-acidophilis milk (Lactobacillus acidophilis)
-bulgarian milk (Lactobacillus bulgaricus)
-cultured buttermilk (Streptococcus cremoris, S. lactis)
-yogurt (Lactobacillus bulgaricus; Streptococcus thermophilis)
-cheese |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
|
| killing microorganisms |
-killed exponentially
-same % will be killed per unit time
-use semilog paper
-should be straight line |
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mcs5109 Sat, 26 Apr 2008 05:17:47 GMT |
|
| HTST |
-71/7C
-15 sec |
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mcs5109 Sat, 26 Apr 2008 04:42:58 GMT |
|
| LTLT |
-62.8C
-30 min |
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mcs5109 Sat, 26 Apr 2008 04:42:58 GMT |
|
| pasteurization |
heating process used to kill most common potential pathogens in milk
-does not sterilize
-microbes reduced by 90%
retard spoilage
-heat/time of exposure of milk so that M. tuberculosis (and 4 other pathogenic microbes) are killed
- |
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mcs5109 Sat, 26 Apr 2008 04:42:58 GMT |
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| pathogens in cow milk |
-lisertia
-salmonella
-mycobacterium tuberculosis
-brucella
-coxiella burnetti (rickettsia cause Q fever) |
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mcs5109 Sat, 26 Apr 2008 04:42:58 GMT |
|
| common spoiling microorganisms in cow milk |
-streptococcus
-lactobacillus
-microbacterium
-pseudomonas
-flavobacterium
-bacillus
-most are harmless |
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mcs5109 Sat, 26 Apr 2008 04:42:58 GMT |
|
| cow milk |
-sterile, but contaminated at udders
-microorganisms introduced eventually spoil the milk |
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mcs5109 Sat, 26 Apr 2008 04:42:58 GMT |
|
| HE results |
-positive for many non-pathogenic enterics (coliforms of E. coli, enterbacter, citrobacter, and non-coliforms that ferment sucrose) (salmon-pink to orange)
-if negative, colonies and medium = blue/green (pathogenic, non-coliform, non-sucrose fermenting; Salmonella, Shigella)
-Salmonella= green colonies w/ black centers
-Shigella= green colonies w/o black centers |
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mcs5109 Tue, 29 Apr 2008 22:45:14 GMT |
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| Hektoen Enteric |
-isolate/ID Salmonella and Shigella
-brom thymol blue and acid fushin dyes
-toxic to GP and most GN enterics
-high [] carbs and peptones
-lactose/sucrose present
-if either lactose or sucrose fermented, colonies turn salmon pink (+ for fermentation)
-bile acids might ppt under low pH conditions
-contains sodium thiosulfate and ferric ammonium citrate
-if H2S produced--> black colonies (independent of sugar fermentation) |
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mcs5109 Sat, 26 Apr 2008 04:27:55 GMT |
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| E. coli and Salmonella |
-both enterics
-GN
-rods
-ferment lactose
-produce H2S |
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mcs5109 Sat, 26 Apr 2008 04:27:55 GMT |
|
| Salmonella |
-many Salmonella strains harmful
-infections from Salmonella called salmonellosis
-colonies mucous surfaces--> typically in intestinal tract
-most severe disease from S. typhii (typhoid fever aka enteric fever, rare today)
-mostly in poultry/eggs |
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mcs5109 Sat, 26 Apr 2008 04:04:14 GMT |
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| E. coli |
-E. coli O157:H7 contaminates hamburger
-has altered genes to cause hemolytic-uremic syndrome--> leads to kidney failure/death
-mostly from undercooked hamburgers
-many E. coli strains harmless |
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mcs5109 Sat, 26 Apr 2008 04:04:14 GMT |
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| pathogenic food bacteria |
-food= nutrient rich
-only some strains of E. coli, Salmonella are pathogenic |
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mcs5109 Sat, 26 Apr 2008 04:04:14 GMT |
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| poultry |
-contaminated during gutting process
-eggs become contaminated with Salmonella via cloaca (passageway for digestive/excretory/reproductive tract) |
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mcs5109 Sat, 26 Apr 2008 04:04:14 GMT |
|
| comminute |
-ground up meat for burgers, sausage
-grinds surface contamination throughout meat
-well oxygenated, nutrient rich medium
-contaminated fluids |
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mcs5109 Sat, 26 Apr 2008 04:04:14 GMT |
|
| beef |
-becomes contaminated during slaughter
-exacerbated when meat comminuted (ground up) for burgers |
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mcs5109 Sat, 26 Apr 2008 04:04:14 GMT |
|
| gut bacteria info |
-temp range from 35-38C
-can thrive in guts of many species
-most harmless/beneficial
-some harmful |
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mcs5109 Sat, 26 Apr 2008 04:04:14 GMT |
|
| 3. Completed tests |
-dark, lactose-fermenting colony of EMB plate streaked onto nutrient agar
-positive if lactose fermented, gas produced, organism is GN rod |
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mcs5109 Sat, 26 Apr 2008 02:37:54 GMT |
|
| 2. Confirmed test |
-performed if + result from presumptive test
-confirms if really coliforms
-inoculum taken of positive tube ans streaked to EMB plate
-reveals dark, lactose-fermenting colonies
-E. coli= green metallic
-E. coli= always of intestinal origin
-Enterobacter and Klebsiella= pink/purple colonies; not always of intestinal origin
-little/no color= non-lactose fermenters (may be intestinal GN) |
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mcs5109 Sat, 26 Apr 2008 02:37:54 GMT |
|
| 1. Presumptive test |
-Most Probable Number (MPN)
-will show presence of organisms that ferment lactose and produce gas--> lactose containing broth and Durham tube
-estimation of MPN per 100mL
-different [] of water sample inoculated into lactose broths, incubated, then checked for acid/gad production
-calculate MPN from gas in tubes and compare to safety standards |
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mcs5109 Sat, 26 Apr 2008 15:16:35 GMT |
|
| standard analysis of water steps |
1. presumptive test
2. confirmed test
3. completed test
-a negative result from ANY test= no coliforms present in water sample/no fecal contamination |
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mcs5109 Sat, 26 Apr 2008 02:37:15 GMT |
|
| EPA water standards |
-<2.2 coliforms/100mL water via MPN method
-or, 1 coliform/100mL via membrane filtertechnique |
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mcs5109 Sat, 26 Apr 2008 02:20:21 GMT |
|
| indicator organisms |
-coliforms
-most non-pathogenic
-GN
-non-spore forming
-Enterobacteriaceae
-aerobic/facultqative anaerobes
-ferments lactose
-present in large #s in gut
-survive longer in water than enterics
-E. coli most common |
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mcs5109 Sat, 26 Apr 2008 02:20:21 GMT |
|
| human pathogens in water |
-bacteria, viruses, fungi, protozoa
-caused mostly by fecal contamination of water supply
-pathogens of intestinal origin cause diseases related to digestive tract (enteric pathogens)
-most fecal contamination not pathogenic
-low #s can cause disease |
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mcs5109 Sat, 26 Apr 2008 02:20:21 GMT |
|
| potable water |
-water intended for human consumption
-doesn't have to be free of microorganisms |
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mcs5109 Sat, 26 Apr 2008 02:20:20 GMT |
|
| biocode |
-produced by adding values of "+" or "-" results
gives species name
-any 1 species can have several biocodes (from variation in strains)
-different biocodes for different strains
-normally, a particular 5 digit biocode= 1 species |
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mcs5109 Sat, 26 Apr 2008 01:45:18 GMT |
|
| Enterotube II |
-for Enterobacteriaceae
-12 different media
-15 different assays
-produces biocode |
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mcs5109 Sat, 26 Apr 2008 01:45:18 GMT |
|
| species |
-collection of different strains
-share many traits and differ from other species
-not all strains w/in a species the same: only 90% E. coli ferments lactose
-must use different assays to ID species |
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mcs5109 Sat, 26 Apr 2008 01:45:18 GMT |
|
| strains |
-populations derived from a single cell
-like a pure culture
-considered clones
-may be 100s per species |
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mcs5109 Sat, 26 Apr 2008 01:45:18 GMT |
|
| miniaturized test systems |
-API 20E System
-API Staph-Ident Sytem
-Enterotube II
-important in clinical setting
-takes <5 hrs sometimes |
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mcs5109 Sat, 26 Apr 2008 01:30:26 GMT |
|
| Bergey's manual od Systematic Bacteriology |
-describes all known microorganisms today |
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mcs5109 Sat, 26 Apr 2008 01:30:26 GMT |
|
| Urea broth |
-contains urea, phenol red (now yellow)
-ammonia liberated, raises pH, turns hot pink
-Proteus + for urease
-Klebsiella gives slow rxn |
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mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| Urease |
-urea= amide compound
-cleaved by urease to produce ammonia and CO2
-urease produced by Proteus
-distinguished from other non-lactose fermenting enteric genera (Salmonella, Shigella) |
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mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| Simmon's citrate agar |
-contains only citrate as C and E source
-contains pH indicator bromethyl blue
-if citrate permease made by cell, CO2 liberated
-creates NaCO3--> alkaline (blue)
-growth/blue= + for citrate utilization
-no growth/green= no citrate utilization |
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mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| Citrate utilization |
-citrate= int. of Krebs cycle
-some organisms can use citrate as sole E and C source
-must produce enzyme citrate permease to absorb citrate into bacterial cell
-converted to pyruvate and CO2
-also produce oxaloacetate and acetate |
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mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| Motility |
-ability to move via flagella
-incolulating needle/stab
-spreads if motile
-(don't confuse w/ mobile) |
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mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| Kovac's reagent |
-contains butanol to extract indole
-extracts indole
-indole reacts w/ dimethyl amino benzaldehyde of Kovac's reagent |
0 |
mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| SIM (indole) |
-tryptophan= aa with indole as R group
-tryptophanase needed to cleave indole off
-distinguished coliforms
-Kovac's reagent
-cherry red= + for indole production |
0 |
mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| SIM agar |
-SIM agar contains cysteine and sodium thiosulfate
-contains ferrous ammonium sulfate
-black= positive for H2S
-contains tryptone (contains tryptophan) |
0 |
mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| SIM (sulfide) |
-cysteine and methionine have S
-cysteine desulfurase removes S atom--> alanine produced
-produces H2S
-H2S can also be produced by reduction of inorganic S compounds, such as thiosulfate
-SIM contains cysteine and sodium thiosulfate |
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mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| methyl red |
-fermentation of glucose
-large amounts of acid?
-red= high acid (below 4.5)
-orange= int. acid
-yellow= low acid (above 5.5)
-enterobacter species MR negative
-E. coli= MR positive
-opposite of phenol red results |
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mcs5109 Sat, 26 Apr 2008 01:02:39 GMT |
|
| Durham tube |
-if bubble present, then gas liberated (CO2 or H2)
-then, + for fermentation
-can have fermentation w/o gas production
-but not vice-versa |
0 |
mcs5109 Sat, 26 Apr 2008 00:39:39 GMT |
|
| phenol red carb tests |
-all enterics ferment glucose
-phenol red= pH indicator determines if necessary enzymes are present to ferment sucrose, lactose
-yellow= + for acid
-red= - for acid (or, acids have been neutralized)
-contains Durham tube |
0 |
mcs5109 Sat, 26 Apr 2008 00:39:39 GMT |
|
| lactose fermentater determining tests |
EMB, MacConkey's, phenol red lactose broth
-further distinction= methyl red, SIM, citrate, urea tests |
0 |
mcs5109 Sat, 26 Apr 2008 00:39:39 GMT |
|
| non-lactose fermenters (enterics) |
-Serratia
-Providencia
-Salmonella
-Shigella
-Proteus |
0 |
mcs5109 Sat, 26 Apr 2008 00:39:39 GMT |
|
| O/F outcome results |
-yellow on top (aerobic), green on bottom (anaerobic): Pseudomonas
-all yellow: entero
-all green: nuthin' |
0 |
mcs5109 Sat, 26 Apr 2008 00:18:35 GMT |
|
| O/F medium |
-oxidation/fermentation
-Pseudomonas (not enteric) species can oxidize glucose to produce acidic byproducts
only under aerobic conditions
-NOT fermentation
-distinguishes from enterics
-enterics ferment glucose to acidic byproducts only under anaerobic conditions
-contains glucose and pH dye
-initially slightly alkaline (green)
-if acid produced, changes to yellow |
1 |
mcs5109 Sat, 26 Apr 2008 00:20:47 GMT |
|
| MacConkey's |
-distingiushes b/w enteric and non-enteric
-selective b/c of crystal violet and bile salts
-selects GN
-presence of lactose and pH dye differentiates b/w lactose fermenters (coliforms, which give rise to pink or red colonies)
-non-lactose fermenters (white colonies) |
0 |
mcs5109 Sat, 26 Apr 2008 00:18:35 GMT |
|
| GN non-enteric genera |
-Alcaligenes
-Pseudomonas (infection in burn patients, cystic fibrosis patients, meat spoilage) |
0 |
mcs5109 Sat, 26 Apr 2008 00:06:25 GMT |
|
| how to distinguish among enteric species |
-citrates, SIM, urea utilization |
0 |
mcs5109 Sat, 26 Apr 2008 00:06:25 GMT |
|
| coliform species |
-ferment lactose rapidly to produce acid and gas
-Escheria
-Enterbacter
-Klebsiella
-Citrobacter
-normal flora of human body necessary for good health |
1 |
mcs5109 Sat, 26 Apr 2008 00:32:21 GMT |
|
| enteric family |
-actually "Anterobacteriaceae" family
-includes genera:
-Escherichia
-Enterobacter
-Klebsiella
-Citrobacter
-Serratia
-Proteus
-Salmonella
-Shigella
-Providencia
-GN
-non-spore forming
-rods
-facultative anaerobes
-ferment glucose |
0 |
mcs5109 Sat, 26 Apr 2008 00:06:25 GMT |
|
| enteric pathogens |
-many intestinal pathogens, though, cause disease related to digestive tract |
0 |
mcs5109 Sat, 26 Apr 2008 00:06:24 GMT |
|
| bacteria of intestines |
-most not pathogens
-imply fecal contamination
-includes bacteria, viruses, fungi, protozoans
-does not ensure presence of pathogens, but increases likelihood of their presence
-many belong to enteric family |
0 |
mcs5109 Sat, 26 Apr 2008 00:06:24 GMT |
|
| novobiocin |
-S. saprophyticus= resistant |
0 |
mcs5109 Fri, 25 Apr 2008 22:21:00 GMT |
|
| coagulase |
-bacterial enzyme that clots fibrogen in plasma
-clotting surrounds organism and physically isolates it from host defenses
-S. aureus produces coagulase
-latex beads coated w/ plasma proteins
-coagulase with cross-link beads, causing clumping
-clumping= + for coagulase |
0 |
mcs5109 Fri, 25 Apr 2008 22:21:00 GMT |
|
| Mannitol salt agar |
-7.5% NaCl= selective for staphylo, micrococcus
-S. aureus ferments mannitol, resulting in yellow color
-some S. saprophyticus ferment mannitol |
0 |
mcs5109 Fri, 25 Apr 2008 22:21:00 GMT |
|
| phenol red glucose broth |
-anaerobic conditions
-if not fermentative, broth remains red (micrococcus)
-if fermentative, broth turns yellow (staphylococcus) |
0 |
mcs5109 Fri, 25 Apr 2008 22:21:00 GMT |
|
| distinguishing staphylococcus from micrococcus |
-staphlyococcus= facultative anaerobes (can use O2 if present)
-grows well w/o O2 to produce acid end products
-micrococcus= aerobes, only grow under aerobic conditions
-produce H2O, CO2
-mannitol fermentation, coagulase, novobiocin |
0 |
mcs5109 Fri, 25 Apr 2008 22:21:00 GMT |
|
| Micrococcus |
-GP
-cocci
-tetrads
-aerobe
-positive for catalase (Staphylo... + too; distinguishes from Streptococci)
-salt tolerant
-found on skin, in environment (soil, water, air) |
2 |
mcs5109 Sun, 27 Apr 2008 16:10:51 GMT |
|
| catalase |
-aerobes/facultative anaerobes
-aka peroxidase
2 H2O2 --> 2 H2O + O2
-positive for catalase if bubbles (O2 released)
-in Staphylococcus and Micrococcus |
0 |
mcs5109 Fri, 25 Apr 2008 21:21:06 GMT |
|
| superoxide dismutase |
-enzyme makes H2O2
2O2* +2H+ --> H2O2 + O2
-(H2O2 also toxic to cells, but not as much as superoxide) |
0 |
mcs5109 Fri, 25 Apr 2008 21:21:06 GMT |
|
| respiratory chain |
-final e- acceptor= O2
-can form superoxide (radical, toxic)
-must produce superoxide dismutase to survive |
0 |
mcs5109 Fri, 25 Apr 2008 21:21:06 GMT |
|
| alpha-rxn |
-very slight clearing
-green/yellowish coloration
-associated w/ lactic acid bacteria that can partially degrade hemoglobin (produces H2O2)
-most oral Steptococci that are not pathogenic |
0 |
mcs5109 Fri, 25 Apr 2008 21:21:06 GMT |
|
| beta-rxn |
-zone of clearing
-caused by B-hemolysins produced in the cells
-most Streptococci (except S. pneunomiae)
-also, S. aureus and Bacillus
-a few scattered B-hemolytic cells not uncommon in healthy swabs |
0 |
mcs5109 Fri, 25 Apr 2008 21:21:06 GMT |
|
| gamma-rxn |
-no hemolysis
-Streptococcus species |
0 |
mcs5109 Fri, 25 Apr 2008 21:21:06 GMT |
|
| hemolysis |
-disruption of red blood cells (erythrocytes)
-zone of clearing if hemolysis occurs |
1 |
mcs5109 Fri, 25 Apr 2008 21:10:22 GMT |
|
| Staphylococcus and streptococcus |
-commonly in skin, skin glands, mucous membranes |
0 |
mcs5109 Fri, 25 Apr 2008 20:39:24 GMT |
|
| S. faecalis |
-recently reclassified as Enterococcus |
0 |
mcs5109 Fri, 25 Apr 2008 20:32:17 GMT |
|
| S. pneunomiae |
-pneumonia and other infections |
0 |
mcs5109 Fri, 25 Apr 2008 20:32:17 GMT |
|
| S. pyrogenes |
-associated w/ upper respiratory infections (URI)
-scarlet/rheumatic fever
-causes strep throat/tonsillitis
-from Group A Streptococcus (specific antigen on surface) |
1 |
mcs5109 Fri, 25 Apr 2008 21:13:29 GMT |
|
| Streptococcus |
-GP
-cocci
-chains
-can ferment in presence of O2
-aerotolerant
-coagulase-negative
-S. pyrogenes
-S. pneunomiae
-S. faecalis
-no catalase
-sensitive to salt |
1 |
mcs5109 Fri, 25 Apr 2008 21:23:16 GMT |
|
| S. aureus |
-differentiated by production of coagulase (coagulates blood plasma)
-high salt [] tolerance (10%)
-produces alpha toxin on blood agar to produce beta-hemolysis
-ferments mannitol
-most important human pathogen of genus
-associated with abscesses, boils, toxic shock syndrome, pneumonia, wound infections |
1 |
mcs5109 Fri, 25 Apr 2008 21:33:47 GMT |
|
| Staphylococcus |
-GP
-facultative anaerobic
-cocci
-single cells, pairs, grape-like clusters
-S. aureus
-S. epidermis
-S. saprophyticus
-positive for catalase
-salt tolerant
-common in oral, resiratory, and lower digestive tracts, skin, salty or dairy products, brines |
2 |
mcs5109 Fri, 25 Apr 2008 21:31:48 GMT |
|
| pathogens |
-organisms that cause disease
-almost all microorganisms can cause disease under right conditions
-finding pathogens in healthy individuals common |
0 |
mcs5109 Fri, 25 Apr 2008 20:32:17 GMT |
|
| proteolytic enzymes |
-hydrolyze proteins
-aka proteases |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:09 GMT |
|
| Milk agar |
-casein= protein imparts white color
-must be degraded by exoenzymes to yield aa's for metabolism
-not selective (contains glucose, lactose, tryptone, yeast extract)
-zone of clearing= produces casein-hydrolyzing exoenzymes |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:08 GMT |
|
| Bacillus differential medium |
-Bacillus= casein hydrolyzer |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:08 GMT |
|
| thermoduric Bacillus |
-will NOT grow at thermophile temps (45-65C)
-can survive up to 80C
-Bacillus= mesophile
-heating soil sample to 80C kills all non-spore-forming Bacillus
-leaves only spores |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:08 GMT |
|
| Bacillus spores |
-endospores= heat-resistant forms of bacteria that enhance survival
-fungal spores= reproductive structure (DO NOT CONFUSE!)
-thermoduric |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:08 GMT |
|
| Bacillus pathogens |
-B. cereus (food poisoning of dairy)
-B. anthracis (anthra of cattle/bio warfare agent)
-B. thuringiensis (produces Bt toxin fatal to insects; used in corn as insecticide) |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:08 GMT |
|
| Bacillus |
-GP
-rods
-mesophiles
-produce endospores (only other GP to do so= Clostriudium)
-common in soil
- |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:08 GMT |
|
| Common GN genera |
-Pseudomonas
-Algaligenes
-family Enterobacteriaceae
-includes genuses:
-Escherichia
-Enterbacter
-Citrobacter
-Klebsiella
-Salmonella
-Shigella
-Serratia
-Proteus
-Providencia |
1 |
mcs5109 Mon, 28 Apr 2008 00:30:43 GMT |
|
| Common GP genera |
-Bacillus
-Streptococcus
-Staphylococcus
-Micrococcus |
0 |
mcs5109 Fri, 25 Apr 2008 20:15:08 GMT |
|
| EMB as Selective and differential mediums |
-ex: EMB contains lactose
-selects for GN or intestinally-derived GP
-if able to ferment lactose, produce acid by-products to turn dyes deep blue/purple
-GN produce a green sheen when they ferment lactose (E. coli)
-E. aerogenes produces dark purple colonies
-non-lactose fermentors produce white colonies
-basically: EMB differentiates b/w lactose fermentors |
2 |
mcs5109 Sat, 26 Apr 2008 00:09:15 GMT |
|
| Differential medium |
-enables differentiation based on metabolic differences
-ex: blood agar
-differences may be seen in colony shape/color of surrounding medium/end-products |
0 |
mcs5109 Fri, 25 Apr 2008 19:57:26 GMT |
|
| EMB |
-selective medium
-eosin/methylene blue dyes
-selects for organisms that can survive in bile salts of digestive tract (also can survive in 2 dyes)
-selects for GN
-selects for GP that can grow in digestive tract |
0 |
mcs5109 Fri, 25 Apr 2008 19:57:26 GMT |
|
| selective medium enrichment methods |
-give desired species advantage
-ex: lactose favors lactose fermentors
-lactic acid favors Proprionibacterium species |
0 |
mcs5109 Fri, 25 Apr 2008 19:57:26 GMT |
|
| selective medium examples |
-low pH favors fungi growth, inhibits bacteria
-high salt [] favors Staphylococcus growth |
0 |
mcs5109 Fri, 25 Apr 2008 19:41:55 GMT |
|
| selective medium |
-helpful to incubate inoculum under exclusive conditions (O2, temp, osmotic pressure, inhibitory substances)
-allows growth for some organisms |
0 |
mcs5109 Fri, 25 Apr 2008 19:41:55 GMT |
|
| 1st step to ID a species |
-reduce microbial load to smaller, more select species
-use selective/differential medium |
0 |
mcs5109 Fri, 25 Apr 2008 19:41:54 GMT |
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