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83 Cards in this Set
- Front
- Back
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FACTS ABOUT WATER
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-seldom if ever pure in nature
-what matters is the kind not the amount of bacteria -water that has autotrophs and sacrophytic heterotrophs is safe (parasitic and pathogens) |
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POTABLE
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Safe to drink
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DISEASE CAUGHT IN CONTAMINATED WATER
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Dysentary, typhoid fever and cholera
they are spread by the fecal-water route through contaminated water |
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WHY IS IT HARD TO EXAMINE WATER
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1. numbers of pathogens may be too low and could be missed
2. when they are detected could be too late to prevent the spread of disease |
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SEWAGE INDICATOR BACTERIA
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E.coli
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E.COLI
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-Belong to the coliform group
-Easy to identify -never appears in nature, only on the large intestines of warm-blood animals -survives longer in water than other human pathogens |
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COLIFORM GROUP
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-Facultative anaerobe
-Gram-negative -non-endospore former -bacilli, random arrangement **ferments lactose sugar to produce gas |
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PRESUMPTIVE TEST
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Gas bubble on Durham's tube
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CONFIRMED TEST
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-Uses both selective and differential media
-E.Coli turns into a green metallic sheen when positive -coliform produce small colonies with dark centers* |
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FACTS ABOUT MILK/FOOD
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-Milk and food can support microbial growth by supplying nutrient
-by leaving food and milk in room temperature it can be an excellent growth medium -unlike water what matters is quantity and not kind of bacteria -the quantity is what determines the sanitary quality -high quality is refrigerated |
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MICROORGANISM FOUND IN MILK
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-Staph. epidermidis
-Micrococcus -E.Coli -Staph. Aureus -Salmonella |
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POUR PLATE METHOD
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-Method used to measure the quantity
-not to count below 30 or above 300 -used for milk and food |
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MAJOR DIFFERENCE BETWEEN MILK AND FOOD
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food is solid so it needs to be aseptically blended with sterile water
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FOODBORNE INFECTION
(fever) |
-ingests food contaminated by microorganism
-delayed symptoms -diarrhea, cramps, nausea, vomiting and fever** -bacterial enteritis, salmonellosis, typhoid fever, shingellosis, traveler's diarrhea |
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MICROBIAL INTOXICATION
(NO FEVER) |
-they are preformed toxins that produced the illness
-grow and multiply in the food and produce poisons -rapid symptoms -diarrhea, cramps, nausea, vomiting, no fever** -staphylococcal enterotoxicosis, botulism, mycotoxicosis |
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RADIATION
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the process of emitting radiation in the form of waves or particles
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IONIZING RADIATION
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-high energy and short wavelenghts
-very penetrating -forms free radicals (removes e-) -free radicals do lethal cellular damage -X-Rays, Gamma Rays |
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NON-IONIZING RADIATION
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-low energy and long wave lenghts
-not very penetrating -blocked by water, paper, plastic or glass -UV light -265nm is what kills cellular DNA (germicidal) |
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GERMICIDAL USE OF UV
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-uses no heat
-lethal to most microorganisms -no good penetrator -used in place of chlorine to purify water -can only sterilize the area in direct contact with light |
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CULTURES USED IN UV LIGHT
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Both G+
Bacillus megatherium- most resistent because is endospore former took one hour Staph. Aureus-less resistent because does not form endospores - took 10 mins |
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STOCK CULTURE
WHAT CAN GO WRONG |
1. chance of contamination is big
2. it can weaken and die, the identification cannot be done in one night 3. Causing variable or no results |
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HOW TO AVOID THE PROBLEM
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Reserver stock culture
Working stock culture |
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RESERVE STOCK CULTURE
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It will not be used for making routine slides or inoculations.
-it is subcultured then stores in the refrigerator as a reserve |
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WORKING STOCK CULTURE
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It is used for making all of the routine smears and inoculations.
If it is old or contaminated it is replaced |
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MORPHOLOGY OF THE UNKNOWN
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-shape (cocci, bacilli)
-arrangement (random, chains, grape-like clusters, tetrads) -G+ and G- **gram staining can reveal all of the morphology |
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CULTURAL CHARACTERISTICS
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The macroscopic appearance of bacteria in or on different kinds of media
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NUTRIENT AGAR SLANT
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growth-scarce, moderate, abundant
color (chromogenesis) opacity (opacity/opaqueness) |
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CHROMOGENESIS
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The production of pigments
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OPACITY-OPAQUENESS
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The quality or state of a body that makes it impervious to the rays of light
-due to the amount of growth and color -opaque -translucent -transparent |
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OPAQUE
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solid growth, no light can go through
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TRANSLUCENT
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Light passes through but you can't see through it
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TRANSPARENT
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Light passes through and you can see through it
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NUTRIENT BROTH
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1. Surface
2. Subsurface 3. Sediment |
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PELLICLE (SURFACE)
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A thick layer or cells across the entire surface of the broth
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MEMBRANOUS (SURFACE)
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A thin layer of cells across the entire surface of the broth
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FLOCCULENT (SURFACE)
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Large, floating mass of bacteria on the surface
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RING (SURFACE)
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Cells only around the side of the test tube
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SUBSURFACE
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Between the top and the bottom of the tube
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TURBID (SUBSURFACE)
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Cloudiness due to cells
Scarce Moderate Abundant |
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GRANULAR (SUBSURFACE)
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Turbidity due to very small floating particles
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FLOCCULENT (SUBSURFACE)
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Small floating masses
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FLAKY (SUBSURFACE)
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Large particles in suspension
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SEDIMENT (Pellet)
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Cells at the bottom of the tube
-Amount (scarce, moderate, abundant) -color -type (granular, flocculent, flaky, viscid) |
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VISCID (SEDIMENT)
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Sticky
Viscous Gelatinous |
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METABOLISM
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All the chemical reactions that occurs within the cells of living organism
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ENZYMES
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Protein molecules that catalyze specific chemical reaction
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ENDOENZYMES
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Enzymes that function and remain within cells.
The majority of a cells' enzymes |
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EXOENZYMES
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Enzymes that are produced inside bacteria but are secrete outside the cell to catalyze reactions external to the cells
-it is necessary because are absorption feeders -it is these specific enzymes that are used to identify the unknown bacteria |
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OXIDATIVE BACTERIA
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-Bacteria that gets energy from organic molecules
-uses oxygen to produce CO2 and H2O *aerobic cellular respiration |
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FERMENTATIVE BACTERIA
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-bacteria uses organic compounds for energy
-produce complex end product (acids, aldehydes, alcohols, hydrogen gas, and CO2) -products can be used to identify them |
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DURHAM TUBE FERMENTATION
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-Negative - red, no gas bubble
-Acid, no gas - yellow, no bubble -Acid and gas - yellow, gas bubble |
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MIXED-ACID FERMENTATION
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-Methyl red test
-E.coli makes a lot of gas -reagent used is methyl red -Red is a positive test -Yellow is negative |
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BUTANEDIOL FERMENTATION
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-Baritt's A - alphanapthol
-Baritt's B - KOH -pink or red is positive -yellow is negative needed 1-2 hrs to get result |
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CATALASE PRODUCTION
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-TSA slant
-add 3% hydrogen peroxide -positive if it bubbles |
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NITRATE REDUCTION
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-nitrate broth
-reagents: nitrate A, Nitrate B - a red color appears immediately if positive Only if negative add zinc -if it turns red is negative -if nothing changes then is positive |
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HYDROLYSIS
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The breaking down of complex organic macromolecules into their smaller, simpler, subunit building blocks in the presence of water
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HYDROLASES
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Exoenzymes which split complex organic compounds into smaller units. It accomplishes the splitting in the presence of water.
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STARCH HYDROLYSIS
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Starch agar plate
-Reagent: iodine -if it turns black/blue starch is still present so is negative for starch hydrolysis -if after adding it has a clear zone, starch is no longer present-positive for starch hydrolysis |
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CASEIN HYDROLYSIS
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-milk agar plate
-casein hydrolysis is indicated by a clear zone Protein hydrolysis is proteolysis or peptonization |
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FAT HYDROLYSIS
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-spirit blue agar plates
-if dark blue precipitate shows, then is positive for fat hydrolysis -fatty acid is what reacts |
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TRYPTOPHAN HYDROLYSIS
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-Tryptone broth
-Kovac's reagent is used to detect product indole -if after adding the reagent a red layer forms at the top of the culture broth is positive |
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UREA HYDROLYSIS
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-Urease broth
-the ph raises which causes the color change -red/pink is positive |
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GELATIN HYDROLYSIS
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-nutrient gelatin tube
-gelatinase is the enzyme that breaks down the gelatin protein -positive result is liquefaction even after refrigeration |
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HYDROGEN SULFIDE PRODUCTION
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-Kligler's iron agar tube
-iron salt in the agar reacts with hydrogen sulfide gas to form a dark black precipitate product |
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MOTILITY
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-SIM tube
-a positive would be the spread of growth outward from the initial stab |
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CITRATE UTILIZATION
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Simmons Citrate agar slant
-changes from green (negative) to a deep Prussian blue (positive) |
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PHENYLALANINE DEAMINATION
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-Phenylalanine slant
-reagent: 10% ferric chloride -Positive result: 1-5 min is dark emerald green color |
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LITMUS MILK REACTION
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-Litmus milk tube
-litmus is ph indicator 5 results -acid--pink -alkaline--blue/purple -litmus reduction--white -coagulation--curd formation -peptonization--clear violet or brown layer |
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CHEMOTHERAPEUTIC AGENTS
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-inhibit or prevent microbial growth without causing harm to individual
-chemical agents that are used internally -may be natural or synthetic |
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ANTIBIOTIC
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-natural
-substance produced by microorganisms that in small amounts inhibit other microorganism |
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SYNTHETIC DRUG
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Manufactured chemical agents that kill or inhibit microorganisms
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HOW ANTIBIOTICS ARE EFFECTIVE
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1. Selective toxic
2. easy to use 3. reliable 4. yields results in a short time |
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BROAD SPECTRUM ANTIBIOTICS
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Effective against a large range of both G- and G+ bacteria
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NARROW SPECTRUM ANTIBIOTICS
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Effective against only a restricted number of bacteria
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MECHANISM ON HOW ANTIBIOTICS KILL
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1.interferes with the synthesis of peptidoglycan
2.targets prokaryotic cytoplasmic membranes 3. interferes with protein synthesis 4. inhibits nucleic acid synthesis 5. interferes with the synthesis of folic acid |
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ZONE OF INHIBITION
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A clear zone of no microbial growth around a disc on an agar plate
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DISINFECTANTS
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chemical agents used on non-living inanimate objects to lower levels of microbes
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ANTISEPTICS
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chemicals used on living tissues and mucous membranes
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MICROBICIDAL AGENTS
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chemical agents that results in microbial death
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MICROBIOSTATIC AGENTS
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Chemical agents that cause a temporary inhibition of microbial growth. when agent is removed, growth resumes
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ACTIONS OF DISINFECTANTS
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1.denatures
2. interferes with DNA structure 3. inhibits protein function 4. disrupts the cytoplasmatic membrane 5. disrupts the cell wall 6. dissolves cellular lipids |
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OLIGODYNAMIC ACTION
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the ability of small amounts of heavy metals to exert an antimicrobial effect
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AGENTS USED
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Phenol
Lysol Bleach Mouthwash Iodine Ethanol Silver Nitrate Copper Nitrate Bleach is full spectrum |
