Microbiology LAB MIDTERM Flashcards

Terms Definitions
Neutrophiles
Like neutral pH.
Mesophiles
Middle-loving organisms (temperature).  Body temp 37 deg C.
ELISA
Enzyme Linked ImmunoSorbent Assay;for the detection of antigens in bodily fluids.
Strep Pyogenes
Beta hemolyticmedically important strepcauses pneumonia and laryngitis
Strains of ___________ can cause typhoid fever and gastroenteritis and are among the most significant pathogens in non-purified drinking water?
Salmonella
XLD Agar Plate
selective -- Gram-negative (growth)differential -- xylose fermentation (yellow), lysine fermentation (pink), and sulfur reduction (black colonies)
Endo Agar
selective: gram- (-); diff.:lactose ferm.; positve: green metallic sheen
disinfection
a process in which vegetative, actively growing, microorganisms are destroyed on non-living objects and surfaces.-disinfectants are only used on inanimate objects b/c are toxic to humans and animals.
Parfocalized
Minimal focusing is needed when switching from one objective lens to the next.
What is the name for infections without symptoms?
subclinical
What distinguishes yeast?
Large size and oval shape
Phenylethanol Agar Plate
seletive -- Gram positive (phenyethanol-growth)
Staphylococci
gram (+), fac anaerobe, clusters, skin normal flora
Ammonification
amine groups are removed from amino acids and converted into ammonia; production of ammonia from organia ammonia.
Nitrogen Fixation
the conversion of atmospheric nitrogen to ammonia
binary fission
asexual reproduction by a separation of the body into two new bodies.
sterilization
the complete destruction or removal of all microorganisms, including viruses and endospores.-the organisms may be killed with steam, dry heat, or incineration,-absolute value...it is either sterile or it is not
Boiling
100 deg C.  Kills most vegetative cells but does not kill endospores.  
What is the upper respiratory tract?
Nose and Throat
What are other diseases caused by EBV?
Burkitt's Lymphoma
Nasopharyngeal
Carcinoma
AIDS
Chronic Fatique Syndrome
What color is usually an indicator of a gram positive bacteria?
Purple
Give three examples of normal residents in the eye conjunctiva.
Staphylococci,streptococci, and neisseriae.
Blood Agar Plate
enriched -- 5% sheep RBCdifferential -- hemolysis (beta-complete, alpha-partial, gamma-none)
different streak patterns
Quadrant Streak - 4 step streakingContinuous- continuous streak
dental carries
the degradation of tooth enamel and dentin in the formation of tooth decay.caused by sugar
Condenser Lens
controls the amount of light entering the objective lens
Refractive Index
The relative velocity with which light passes through one substance compared to another.   If substances have different refractive indices light passing through both substances will be refracted at the boundary between the substances.  This is the reason we use oil on 100x obj. lens - it has almost the same refractive index as glass. 
Opportunistic Pathogens
Do not normally cause disease in healthy immunocompetent individuals but under certain conditions they can cause disease.
In the indirect test what body fluid would you obtain from the patient in order to perform the test?
serum (plasma)
beta-Lactamase Test
a rapid test to determine is a bacterium is resistant to penicillins ot cephalasporins
Quality Control of Milk--Total Coliform Test
enumeration of coliforms;uses violet Red Bile Agar
magnification
the ability of a lens or lenses to make an image largerto have the power of causing objects to appear larger than they are.
Pure Culture
A culture that contains only one type of organism.  Technically, in a pure culture all the cells are the progeny (offspring) of a single cell.
Yeast appear Gram + or Gram - on staining?
Gram +
what are some common pathogenic microbes found in food?
Salmonella, Shigella, E.coli, Listeria monocytogenes, Staph. aureus
simple stain
a single dye which is added to the smearone step staining procedureuse of single stain to color a bacterial organism
Streak Plate Method
A solid agar plate is divided into four quadrants.  A loop is used to deposit the specimen onto the first quadrant.  The loop is flamed and is drag through part of the first quadrant to pick up cells and drawn into the next quadrant.  This is repeated until quadrant four has, ideally, only a few, isolated cells.  
Blood agar is a differential and enrichment agar. Why?
Differentiates based on hemolytic reactions.
Enrichment because it adds nutrients (sheep blood) to enhance growth of bacteria.
What organism causes Strep throat, and what does the Strep test detect on the organism?
Strep. pyogenes;Lancefield Group A antigen
What are the results that can be concluded about streptococcus from hemolytic observations?
Alpha and Gamma streptococci are normal flora.
Beta streptococcus are pathogens (S. pyogenes)
What is the common denominator of all EBV diseases?
Elevated antibody titers (levels) usually IgG.
When using the Kirby-Bauer test why are the areas of clearing around the disks different diameters even though both might be considered sensitive for that organism?
The diameters may be different because
 
the rate of diffusion of the disks into the media may differ,  and/or 
the degree of the microbe's sensitivity to the antibiotics may vary. Both however, may be still be considered effective against the microbe (based on charts of previous tests).
What can go wrong with Gram Stain
over/under use of decolorizersmear can be too thick and not decolorizedcultures cannot be more that 24 hrs old and can begin to decomposetoo much heat fixing, causing cell walls to rupture
What is the basic setup for the ELISA test?
Testing of blood (synthetic) serum
Four students (Suzy, Mary, Carol and Irene) who are suite mates complaing of fatigue.
Two controls (positive and negative)
Why is the ELISA test so sensitive?
ELISAs are very sensitive due to highly specific antibody – antigen interaction.
What are the dying steps to acid fast staining?
Apply carbol fuchsin (primary pink dye)
Decolorize - washes pink dye of non acid fast bacteria
Methylene blue (counterstain blue dye) - stains bacteria that do not hold carbol fuchsin.
What was the purpose of the positive control?
To demostrate to the positve test results
To verify the EBV with Secondary will produce positive result.
What are the two results of the ELISA test?
Blue/Green color - Positive (Suzy and Carol)
No color/clear - Negative
Predict the results if a very low concentration of antigen were loaded in a well. What would happen if not enough antibody was incorporated?
If there was a low concentration of antigen loaded in a well, and not enough antibody was incorporated into the agarose, you would see no pricipitin ring (if [antigen] is greater than [antibody]).
 
Or, a ring of very small diameter may be seen if there is enough antibody to equate to the low concentration of antigen (zone of equivalence is met).
What is the role/purpose of PBS buffer in the ELISA assay?
The PBS buffer was used to wash excess antigen and antibodies from wells, and as a negative control.
Staphylococcus epidermis
coagulase- negative
Obligate anaerobes
Cannot have oxygen
substances that inhibit bacterial growth
bacteriostatic
What is Barritts Solution A?
Alphanapthol
Streptococcus agalctine
Gram positiveHemolysis- betaLitmus- on going
In conjugation the whole chromosome (is/is not) transfered
NOT
What stains the bacteria purple?
crystal violet
What is autoclaving?
steamed heat under pressure
Catabolic reactions
breaking down substrates= generates energy or subunits to be used by the cell.
What are examples of obligate anaerobes?
Clostridium
Bacteroides
The total magnification obtained when the 4x (scanning) lens is in place is?
40 x
Oxidase test
Used to identify bacteria containing the respiratory enzyme cytochrome oxidase, which is responsible for the transfer of electrons to oxygen, reducing it to water. Can identify the oxidase positive Neisseria. It can also differentiate between oxidase negative Enterobacteriaceae from oxidase positive Psuedomonadeaceae A positive test comes out purple or dark bluea negative test has no color change
The conversion of ammonia to nitrite and the subsequent conversion to nitrate is called
Nitrification
Transfer without the spread of organisms.
aseptic transfer
What is the shutter-like structure within the condenser that regulates the amount of light that reaches the specimen?
iris diaphragm
What are organisms that grow and multiply in a container of culture medium?
culture
pH conditions: A. faecalis
grows in alkaline pH
How do you interpret the lysine decarboxylase test?
Positive-purple
Negative-yellow
What are metachromatic granules?
Distinct reddish-purple granules within cells that show up when the organisms are stained with methylene blue
Types of flagella
Monotrichous- has a single flagellum and is said to be polarAmphitrichous- flagella at both ends of cellLophotrichous- tufts of flagella at the end of the cellPeritrichous- flagella emerging from the entire cell surface
Production of wine is a fermentative process carried out by which organism
Sacchromyces cerevisae
While in liquefied state, solid media can be placed in test tubes, which are then allowed to cool and harden in a slanted position, producing________ _________.
agar slants
What is when a plate,broth, or slant have come from a previous slant, broth, or plate rather an organism?
subculture
What is the media of agar and nutrients for sampling the surface of the environment?
rodac
If you streaked for isolation from a dilution of .1 ml..and get 53 colonies on the plate..how many were in the original sample?
530
pH conditions: L.Lactis
grew in acidic conditions (pH 3-4)
What test uses the Tryptone Broth?
Tryptophan Hydrolysis/"Indole Test"
What does oxaloacetate + Citratase produce?
Pyruvate plus CO2
What are semi-synthetics?
Chemically altered antibiotics to make them more effective
What are sanitizers?
Agents that reduce microbial numbers numbers to a safe level
What type of microscope has The background is completely light-free and objects in the field become brightly illuminated by rays of light from the illuminator?
Darkfield microscope
What are Substances such as alcohol or betadine that inhibit microbial growth or kill microorganisms?
Antiseptics
What is the effect of temperature on E. Coli?
Mesophiles/Thermophiles
Litmus Mile Reaction results
Pink Color- acid reaction, by splitting of disaccharide into monosaccharides glucose and galactose.PInk and solid- acid clot, from accumulating acidFissures in clot- gasClot broken apart- stormy fermentationWhite color (lower portion of medium)- reduction of litmusSemisolid and not pink; clear to gray fluid at top- Curd, from caseases in bacteria that coagulate casein.Clarification of medium; loss of "body"- Digestion of peptone; peptonizationBlue medium or blue band at top- alkaline reaction
To add organism you do not want is called_____
contaminating
Describe the Streptolysin S
It is oxygen-stable but expresses itself optimally under anaerobic conditions as well
What is a moist heat process used in beverages to kill pathogenic bacteria and reduce the number of nonpathogenic bacteria?
pasteurization
What is brownian motion?
vibrating motion caused by bacteria being struck by H20 molecules.
The following has what gram reaction and what morphology? give a possible species.
Gram +Rod shapedBacillus Cereus
How do you interpret the urease test?
Positive-intense pink
Negative-no color change
What are obligate aerobes?
Bacteria that require oxygen for growth
What is it called If an agent inhibits the growth of bacterial cells but does not kill them?
Bacteriostatic
What type of bacteria are escherichia coli? What shape? Form spores? Aerobe or anaerobe?
Gram negative
Rods (Bacilli)
No
Facultative Anaerobe
Two forms of nitrogen fixation. what are they? and give a modern organism?
1.) Symbiotically- rhizobium2.) Non-symbiotically- azotobacter
Staph epidermidis have caused problems where doing what?
In hospitals on plastic prosthetics and heart valve replacements. Virtually impossible to eliminate from the O.R.
What is the amount of time required to kill a species at a given temp?
thermal death time
What is the other name for micrometer or nanometer?
micron and millimicron
What cellular structure is differentially stained using the Gram technique?
The cell wall (peptidoglycan (+ve) vs. none (-ve))
What is Used to determine the ability of an organism to reduce nitrate to nitrite or nitrogen gas by production of the enzyme nitratase?
Nitrate reductase test
What kind of medium is used for Methyl Red TEst and Voges Proskauer Test?
MR-VP Broth
What are microaerophiles?
Bacteria that prefer to grow in oxygen concentrations less than that found in the oxygen
Refers to the ability of lenses to reveal fine detail or 2 points distinctly separated
resolution or resolving power
what 2 genetic elements are necessary for a plasmid to have in order for transformation to occur
1.) Origin of replication2.) selectable marker
What are the two forms of streptolysins?
Streptolysin O and Streptolysin S
When are transmission-based precautions used?
When a patient is actually known or suspected to be infected with a highly contagious or epidemiologically important pathogen.
What kind of medium do you use for catalase test?
Nutrient Agar Slant
What type of test uses Kliger's Iron Agar?
Hydrogen Sulfide Production test
What is a condenser?
A lens system that is located under the stage; collects light and directs it from the lamp to the slide
What type of bacteria are acid fast? What is the defining property?
Mycobacterium
Mycolic acid (waxy)
in the membrane filtration analysis of water a FSC (fecal streptococci count) was obtained by using what media
KF agar- which contains sodium azide and inhibits growth of all genus except streptococci which will change the plate from purple to yellow.
In testing the effects of osmotic pressure on microbial growth we used e.coli and s. aureus. in what conditions did these grow that the other couldnt?
E.coli grew in high glucose concentration.S. aureus grew in high salt concentrations.
5th step in culture transfer techniques for an 'aseptic transfer' of microorganisms.
the instrument is removed, the necks of the tubes are re-flamed, and the caps are replaced on the same tube from which they were removed.
What does the PH in the killit ampule have to be to turn yellow?
at or below 6.8
What is expected in a capsule stain?
The background is dark (crystal violet) and the capsule appears in white with the black bacteria enclosed in the white capsule
What type of medium do you use for the Hydrogen Sulfide Production test?
Kliger's Iron Agar
What should you do before sticking a sterilized loop into bacteria?
Flame the bacterial culture top
List four ways S. aureus is different from S. epidermitis
1.) aureus coagulates blood2.) it grows on DNA plate3.) it is topographically gold4.) MSA aureus- yellow
What do Y- Hemolysins do?
It is non hemolysis and appears as a simple growth with no change in the medium
why is nutrient broth undefined media?
Because we do not know its exact chemical formula
What is starch hydrolysis used for?
used to determine the ability of an organism to hydrolyze (break down) starch
What does the hydrogen sulfide production test do?
Used to determine the ability of an organism to produce H2S
How does the catalase test work?
Hydrogen peroxide is formed as an end product of aerobic breakdown of sugars. When H202 accumulates, it becomes toxic. Catalase decomposes H2O2 and enables the organism to survive. Only obligate anaerobes lack this enzyme
2H2O2 + Catalase = 2H20 + O2
In testing the effects of heat on microbial growth nothing grew at 100 degrees but 2 organisms grew at 70 what were they?
Bacillus cereus formed some spores at 70 degrees and Aspergillus niger produced alot of spores at 70 degrees.
how does UV light kill bacteira?
it is a form of radiation. it causes THYMINE DIMERS to the bacterial DNA. this causes frameshift mutation in the whole genome and ultimately death.
How do you calcuate incidence rate
Number of new cases in a time period over size of at risk population at midpoint of time period X K
Why use buffers in the testing of pH conditions?
Because the organisms themselves will begin to change the pH by fermentation and/or wastes.
What is the methyl red test used for?
Determining the ability of an organism to produce mixed acid end products from glucose fermentation
What is the zone of inhibition?
an area around an agent that kills of bacteria
in the food analysis lab why did we swab our noses and then perform a dilution and finally plate it? (hint: plated on MSA)
Wer were testing for Staph Aureus which is part of the normal flora but can be deadily if you are shedding it.
What are the goals in preparing a smear?
Cause the cells to adhere to the slide
Insure that shrinkage of cells does not occur
Thinness of smears
What makes up a virus? why are they "not alive"?
virus is a piece of genetic material (ss/ds RNA/DNA) in a protein coat. They are not considered "live" because they cannot reproduce or function independently of a host.
Which plate would you use if you were checking whether your patient's upset stomach was salmonellosis or traveler's diarrhea?
Use manitol salt agar plate. if the organism does not grow it is most likely Salmonelosis. if it does and turns yellow (Staph aureus= travelers diarrhea). To be sure also innoculate Crystal violet and gram -ve salmonella typhimurium should grow and Staph not.
Cell Morphology
Main:cocci-spheresbacilli- rodssspirilla- spiralsVariations:Vibrios- curved rodscoccobacilli- short rodsspirochetes- flexible spirals
Enteric
gram negative rod shaped bacteria
Clostridium botolinum-causes-dangerous because-treatment
gangreen and tetanusproduces exotoxinlarge amounts of antitoxin
What is the shape of Ecoli
Rods
Escherichia coli
Gram negativeEMB Plate- green/metallic sheenPEA growth- low growthMSA- no growthMacConkey- reddish growth
Restriction endonucleases
Naturally occuring bacterial enzymes that cut up any foreign DNA in the bacterial cell (serve as immune system)
How can you kill endospores?
fractional sterilization
What are disinfectants applied to living tissue?
antiseptics
Selective/differentialfor what? how?Manitol Salt agar plate
Differential and selective.High salinity only allows Staphylococcus genus to grow. while the manitol sugar is broken at different rates to differentiate between species.
What aer Chemically altered antibiotics to make them more effective?
Semi synthetics
Bacitracin Susceptibility Test
used to differentiate between beta-hemolytic group A streptococci from other beta-hemolytic steptococci.Similar test can be done with other antibiotics like the Noviobiocin test we did. The antibiotic diffuses into the agar and inhibits growth of susceptible bacteria
Transduction
is mediated by ciruses that inject genetic material into the cell.
Wire loops and needles are extremely durable instruments and are easily sterilized by incineration in the _______ (hottest) portion of the Bunsen burner flame.
Blue
What is the term capable of inhibiting bacterial growth?
bacteriostatic
What is the rod cell shape name?
bacilli
Selective/differentialfor what? how?MacConkey agar
Maconkey is differential and selective. It has crystal violet (selective) no gram positive)) and lactose w/ indicators (differential)
What is the illuminator?
Area that provides light
Litmus Milk Medium
used to differentiate members within the genus Clostridium. Differentiates Eneterobacteriaceae from other gram-negative bacilli based on enterics' ability to reduce litmus.
three methods for genetic recombination
Conjugation, transformation and transduction
What sequence do restriciton enzymes recognize and excise?
pallindromic ex. AATGCCGTAA
A liquid medium lacks a solidifying agent and is called a ________ _______.
Broth medium
What is the growth of microorgansims that contains more than one organism?
mixed culture
What is it called that different media refract at different angles?
refractive index
What is the term of capable of killing microorganisms?
germicidal
What type of gram organism has bacterial cell walls that are rich in mucopolysaccarides that enable the cell to resist decolorizer?
gram positive
Intracellular enzymes
are produced inside the cell and function there. (Catelase)
What medium does the urease test use?
Urea Broth
What test uses simmons citrate agar?
Citrate utilization test
What are antimicrobials?
Compounds that kill or inhibit microorganisms
What is an example of an acidic dye?
Eosin
What is an example of aerotolerant anaerobes?
Streptococcus pyogenes
What are Bacteria that can't tolerate oxygen and must be cultivated under conditions in which oxygen is removed, otherwise they are killed
Obligate Anaerobes
Pathogenic staphylcoccus v nonpathogenic staphylcoccus on MSA
Pathogenic ones will turn the indicator yellow, forming a yellow halo around the growth. Non pathogenic ones will have good growth with no color change.
These organisms that do not belong are called__________
transient flora (moving)
What is Dental Caries primarily caused by?
Lactobacilli and streptococci
What is the small outer know used only for adjustments when looking through the microscope on oil immersion?
fine adjustment
Phenol red carbohydrate broths (red to yellow)
Organism fermented the carbohydrate.
What does urea + urease produce?
2 ammonia plus CO2
How does phenylalanine deamination test work?
Phenylalanine + Phenylalanase = Phenylpyruvic Acid + NH3
How can you tell if a bacteria is aerobic or anaerobic or facultative?
Aerobic-top
Anaerobic-bottom
Facultative-middle
What kind of bacteria is bacillus subtilis? What shape? Aerobe or anaerobe? Form spores?
Gram positive
Rods (Bacilli)
Aerobe
Yes
limit of resolution
They refer to the ability of a microscope to distinguish between two objects.
Why does heat kill bacteria?
it causes permanent denaturation of proteins and enzymes.
What makes up the culture medium?
Water-to desove the nutriants andBroth mixed with agar to solidify.
What is the purpose of the dichotomous key?
to identify an organism
What is a micrometer equal to and nanometer?
10-6 meter10-9 meter
What does Starch + Amylase produce?
Maltose + Glucose + Dextrin
What does H2S + ferric ions produce?
Ferrous sulfide (black precipitate)
What are a Group of anaerobes that can grow in the presence of oxygen, but dont use it?
Aerotolerant anaerobes
Organisms that don't ferment Sugars on Hektoen Enteric Agar
produce blue-green colonies, examples are Salmonella, Shigella, and ProteusProteus and Salmonella specied that reduce sulfur to H2S form colonies containing a black precipitate.
In the bacterial transformation lab how did we prove that transformation occured?
The original "competent cells" were placed in two tubes (control- no plasmid) and experimental (with plasmid). recall the plasmid was for ampicillin resistance. Now both were plated on ampicilian plates and only the experimental e.coli grew because they had transformed and incorporated the ampicilin resistant plasmid into thier own DNA.
Name three ways infectious diseases are transmitted
inhalation, direct skin contact, blood to blood contact
What is the temp at which a species dies at a given time?
thermal death point
How does the oxidase test work?
Aerobic organisms obtain their energy by respiration, which is responsible for the oxidation of various substrates through the cytochrome oxidase system. Obligate aerobes have this enzyme
What is the procedure for Tryptophan Hydrolysis/"Indole Test"?
Inoculate broth with organism
Incubate at optimum temperature
Add 10-12 drops of Kovacs Reagent
Interpret
What is the time required to kill a suspension of cells or spores at a given temperature?
thermal death time
Group C strep- cause- can be identified by?
sore throats and fever.Sensative to synergism with the combination of (trimethoprim and sulfamethoxozole).
UV light kills bacteria by producing thymine dimers throughout its genome. what are two ways this is corrected?
1.) photoreactivation- when light of a particular wavelength stimulates enzymes to repair the dimers.2.) excision repair- whereby restriction enzymes excise the damaged DNA and replace it with the correct sequence.
2nd step in culture transfer techniques for an 'aseptic transfer' of microorganisms.
The tubes are uncapped by grasping the first cap with the little finger and the second cap with the next finger and lifting the closures upward. Once removed these caps must be kept in the hand that holds the sterile inoculating loop or needle. The necks of the tubes are briefly passed through the flame.
Give three reasons why serial dilutions are performed.
1. Bacteria can be counted2. Bacteria counted can be more accurate3. There are varying numbers of bacteria in different biological sites
The following organism has what gram reaction and what morphology and yet it is known not to be Staphylococcus Aureus, why?
Both are gram positive and coccus shape, BUT M. luteus clump in duplets or quads.
How do you interpret the phenylalanine deamination test?
Positive-a deep green color appears within 1-5 minutes
Negative-amber color develops
What is a phase contrast micrscope?
A microscope that is able to differentiate the transparent protoplasmic structures and enhances a contrast between a cell and its surroundings
What are the four types of streaking in the streak plate method? Which is best?
Quadrant Streak (Method A)
Quadrant Streak (Method B)-Best
Radiant Streak
Continuous Streak
An alternative method for testing water is the memrane filtration analysis of water where
water to be tested is passed through a membrane with holes large enough to allow water to pass but to small for bacteria to pass. the filter papers are then plated to check for bacterial growth.
If it is plate dilution take # of colonies X plate dilution if it does not say plate dillution then take the dilution factor x .1 (pippete) X the number of colonies
ignore .1 ml were plated.
Why might the enterotube not give accurate results?
The amount of organism getting to each compartment can not be assured.
What is the drawback to hot oil methods?
Following the treatment, there is cleaning and drying- which may introduce new microbes
Carbohydrate phenol red test (gas in durham tube)
This means that the carbohydrate was fermented and CO2 was most likely produced and released as a by-product.
What is the Urease Test used for?
To determine the ability of an organism to split urea to form ammonia by the action of the enzyme, urease. Media also contains the pH indicator phenol red which turns an intense pink at basic pH
How does a gaspak anaerobic jar work?
Water is added to chemicals too generate H2 and CO2, oxygen is removed from chamber by combining with hydrogen to form water
In the standard analysis of water it is unfeasable to detect all organsisms instead what is done?
The water is tested for indicator organisms whose presence suggests that water may be contaminated (E.coli)
How do you know if you have growth in a nutrient broth?
turbidity appears or a button
In MSA plate change from red to yellow indicates
the organism can ferment mannitol and the acid produced as byproduct lowers pH to YELLOW. (Phenol red)
What is the nitrate reductase test used for?
Used to determine the ability of an organism to reduce nitrate to nitrite or nitrogen gas by production of the enzyme nitratase
Why is thermal death point and thermal death point important? Example?
Good industry canned foods must be heated to kill endospores
Clostridium
At the end of each lab period. __________ the bench top with _____________. Wash __________ with _________ and hot __________.
At the end of each lab period. Disinfect the bench top with disinfectant. Wash hands with soap and hot water.
How can you tell if a bacterium is non-acid fast?
They are easily decolorized by acid alcohol
In the normal flora lab we used the Chocolate agar plate to grow species. Why use this media?
Chocolate agar is media used for the most delicate bacteria for which even blood agar is to harsh (has been heated to detoxify heavy metals).
Plate dilution- say 36 counted on a 10-5 plate dilution. How many bacteria?
36 X 10^5= 3,600,000 no need to add an extra fold. Plate dilution is the multiplication factor.
Staphylococcus saprophyticus
Novobiocin- no sensitivity
Proteus vulgaris
Motility- motility observedGram- negativeTemp- incubator showed small growth, should grow around 23 degrees C
What is a disease-causing organism?
pathogen
Pseudomonas aeruginosa
Negative Stain- small, clustered bacillusGram stain- negativeEMB Plate- PurplePEA Plate- limited growthMSA Plate- no growthMacConkey Plate- Yellow growth
substances that kill bacteria are called
bactericidal
Biohazardous labels: Rating what is 0-1-2-3-4?
0-minimal1-slight2-moderate3-serious4-extreme
What is this cell arrangement? oooooo
strepto
Crystal violet, nigrosin and methelene blue are examples of...
Simple stains
What does NO3 + Nitratase produce?
NO2
What zoom is the ocular lense?
10x
Brownian motion
motion created by collisions with water molecules, does not show true motility in bacteria. They seem to vibrate in place
what were some of the antibiotics used in lab
PenicillinChloramphenicolGentamycinVancomycinStreptomycinTetracycline
To add organism you want is called_____
inoculate
What is the mechanical removal of microbes or move them around?
degerming
Name some vegetative bacteria that are moderately resistant.
m. tuberculosis,s.aureus,psuedomonas
Microaerophiles
Species that grow if provided only with a little bit of oxygen.
What breaks down large proteins into smaller ones?
Gelatinase
What is an extracellular slime layer called? What is it made of?
Capsule
Glyococalyx
What are four types of circle bacteria?
Dipplococci
Tetrads
Streptococci
Staphylococci
Basic stains
are the result of the auxochrome becoming positively charged by picking up a hydrogen ion or losing a hydroxide ion. It then becomes attracted to the negative charges on the surface of most bacterial cells making them colored.Examples are methylene blue, cyrstal violet, and safranin
Leishmania species
form ulcerative lesions on the skin may also attack internal organs. transfered by sand flies.
The survival and continued growth of microorganisms depend on an adequate supply of nutrients and a favorable growth environment. A solution containing these nutrients is a____________
culture medium
What is the selection of bacteria from one culture for growth in a different culture without contamination by unwanted microorganisms?
aseptic transfer
What is the process of inoculation a plate,slant,or broth from a previous plate,slant, or broth, rather than from a specimen?
subculturing
What is the flat platform between the upper lens system and lower set of devices for providing light with a hole in the center allowing light to pass through?
stage
what gram reaction and cell morphology. Name a potential species
+ veCoccusStaphyloCOCCUS aureus
What is the indicator in Carbohydrate Fermentation Tests?
Phenol Red
What test uses lysine decarboxylase broth?
Lysine decarboxylase test
What is an example of a microaerophile?
H. Pylori
What type of bacteria are streptococcus pneumoniae? What shape? Aerobe or anaerobe? Anything special?
Gram positive
Diplococci (circle)
Anaerobe
No
A differential stain to be use to differentiate between microorganisms
gram staining
the enterotube is an example of a ________________ system. it is primarily used for organisms of the family _____________________.
Multitest system.Enterobactericae
Describe the Streptolysin O
IT is oxygen-labile and expresses maximal activity under anaerobic conditions
What does staphylococcus epidermis look like on a slide?
blue and gram + cocci
Aerotollerant Anaerobes
those that can live in the presence of Oxygen or not with no difference.
How do you interpret Methyl Red test?
Positive-red color develops
Negative-yellow color develops
What type of test uses Tryptic Soy Agar Plate?
Oxidase Test
How do you interpret Voges-Proskauer Test?
Positive-Wine red color develops
Negative-Brown color develops
When do you heat fix a capsular stain?
After staining
What is a Solid medium to determine oxygen requirements of different bacteria?
TGYA shake
What is A lens system that is located under the stage; collects light and directs it from the lamp to the slide?
Condenser
Eosin Methylene Blue Agar (EMB)
Used for isolation of fecal coliformsContains sugars to encourage growth of fecal coliformsInhibit growth of Gram-positive organisms
How dowe makee.coli comptent?
place cells in COLD calcium chloride followed by heat shock. this process facilitates transfer of DNA across the membrane
What are three major types of Hemolysins?
Beta, Alpha and Y
What is the gram organism that have a cell wall high in lipid content and alcohol breaks down the lipid allowing the crystal violet-iodine complex to escape from the cell wall?
gram negative
TFTC vs. TNTC
Plate count must be between 30 and 300.Less than 30 TFTCMore than 30 TNTC
What type of test uses a starch agar plate?
Starch Hydrolysis
What medium is used for the carbohydrate fermentation test?
Glucose broth
Lactose broth
Mannitol broth
Maltose broth
Sucrose broth
How do you interpret Starch Hydrolysis?
Positive-zone of clearance appears adjacent to the streak line
Negative-No clearing; only a black/blue area surrounding the streak line
What is A method of separating one species of bacteria from another by diluting one loopful of organism into three liquefied nutrient agar plates?
Pour plate method
What is the auger used for Antimicrobial Sensitivity Testing? Whats the method called that we use?
Mueller-Hinton II agar
Kirby-Bauer Method
How negative stains work
the chromogen in the dye solution is acidic and carries a negative charge. The negative charge on the bacterial surface repels the negatively charged chromagen, so the cell remains unstained against a colored background
3 main ways antobiotics kill bacteria
1.) inhibit cell wall synthesis2.) interupt ribosomal activity3.) destroy cell membrane
What is when a urine specimen is collected using the aseptic technique?
clean catch, mid stream
Phenol red carbohydrate broths (red outside yellow inside)
organism OXIDATIVELY break down the peptones in the broth~ PROTEOLYSIS (pH goes up)
How do you interpret oxidase tests?
Positive-organisms change color to a dark red/black
Negative-no change
How long is the india ink or negrosin left on the slide for negative staining?
Leave it on
Metallic Sheen on Endo Agar
is produced due to large amounts of acid from lactose fermenters like Escherichia coli and Klebsiella pneumoniae
How were strep species originally classified into groups. Now how are they classified?
They used to be classified according to their hemolytic ability on blood agar plates. Now, they are classified by the antigens on their cell surfaces.
What is the problem with boiling?
The heat tolerance of many microbes is unknown.
what is the purpose of the time exposure experiment with the decontaminatant?
Determines time for bacteriocidal effect of the disinfectant at the manufacturer's concentration
Why is the gram stain the most important staining procedure in microbiology?
Because it differentiates MANY bacteria. Basically cuts in half.
What is the procedure for The Litmus Milk Test?
Inoculate litmus milk media
Incubate at opt temp
Interpret
What 2 dyes were used in capsular staining? What bacteria was used?
India ink and Crystal violet
Klebsiella pneumoniae
Lactose fermenters vs. non fermenters on MacConkey Agar
Neutral Red Dye is used and is colorless at pH over 6.8 and red at pH under 6.8Acid accumulating from lactose fermenters turn a shade of red on the agar while the non fermenters remain their normal color or the color of the medium. Formulations without crystal violet allow growth of Eneterococus and some species of Staphylococcus, which ferment lactose and appear pink on the agar
to truly get an accurate view of a fungus, we should view _________________. so in the fungi lab we did what slide preparation? how?
THALLUS (whole body)Henrici slide prep:petri plate is lined with moist paper upon which a microscope slide is placed and a drop of Aspergillus niger is placed bounded on three sides by petroleum jelly and finally a cover slip is placed on top.
What kind of stain is this? what medical importance does this serve?
Capsule, capsules enter the body without detection (NO PHAGOCYTOSIS)
What is the gelatin liquefacation test used for?
To determine the ability of an organism to produce the enzyme gelatinase, which liquifies gelatin
What is the diaphragm on a microscope?
Regulates the amount of light that reaches the slide
what does the distance the DNA traveled quantify?
Recall DNA is negative and "runs to the red" (positive electrode)...The distance it travels is dependent on its size, charge and conformation.
6th step in culture transfer techniques for an 'aseptic transfer' of microorganisms.
The needle or loop is again flamed to destroy remaining organisms.
What are the rules when counting colonies?
-Dont count any less than 30 or anymore than 300.
What is a catalase Test used for?
To test for the presence of enzyme catalase
Why is agar preferable to gelatin as a solidifying agent in culture media?
agar has no nutritional value so bacteria cannot feed off of it. The agar remains solid until it is melted at 100 degrees celcius and then cooled at 40 degrees celcius where it remains solid. Solid agar is better for bacteria to grow because microbes can't degrade it.
What is the Voges Proskauer Test used to determine?
The ability of an organism to produce acetoin 2, 3 butanediol, and ethanol which cause less lowering of the pH than methyl red positive organisms
What did S. aureus do in the blood culture? Conclusion?
Took over plate and made it yellow
Alpha hemolytic
In the normal flora lab how is the presence of Neisseria sicca on the chocolate agar plate confirmed?
the species has the enzyme to OXIDIZE Cytochrome C. when in contact with the reagent tetramethyl-p-phenylene diamine, the reagent will turn dark blue-black if cytochrome oxidase is present.
When starting with a liquid media, how should one start a smear?
Placing one or two drops of the media right onto the slide
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