Is a thin film of bacteria growing at the surface of nutrient broth, which means it is a strict aerobe (requiring oxygen for growth).
Bacteria growing at the bottom of a broth, could be a facultative anaerobe or an anaerobic bacteria (a bacteria that grows without oxygen).
is growth of a bacteria that occurs throughout the broth, such as a facultative anaerobe (a bacteria whose growth is accelerated by the presence of oxygen).
Has one basic dye with a positive charge.
It shows the morphology of the bacteria meaning the shape and arrangement of the bacteria.
What type of stain do Clostridium and Bacillus require?
Spore Stain which uses Malachite Green and Safranin. Water is decolorizing agent
What type of organisms require Acid Fast stain?
Mycobacterium (a gram positiver bacillus containing mycolic acid).
What happens to the capsule of an organism after a negative or capsule stain?
The capsule remains clear because no dyes can stain a capsule.
When put in a motility medium how does one determine if the organism is motile or non-motile?
Non-motile organisms will only grow along the puncture line of the medium.
Motile organisms will grow and spread out form the puncture line of the medium.
What is a fomite?
A fomite is an inanimate object or substance capable of carrying infectious organisms, such as germs or parasites, and spreading them to living things.
What types of tubes are used to determine if an organism is a ferementor of carbohydrates?
Durham Tubes (designed to catch gas bubbles).
What does it mean when a durham tube is red?
It means that it is basic and a negative result for carbohydrate fermentation.
What does it mean when a durham tube is yellow?
It means it is acidic and a positive result for carbohydrate fermentation.
What does it mean when there appears to be air in the Durham tube?
It means that the carbohydrate fermentation produced gas bubbles which were trapped there.
What does a positive reaction concerning starch digestion look like?
Positive for Amylase is a halo visible around the area where starch is utilized.
What enzyme is used in DNA digestion?
Enzyme Dnase - which breaks down long chains of DNA, and uses Methyl Green dye.
What does a positive Dnase result look like?
A clearing around the streak on the streak plate. A clear halo.
What enzyme is used in indole production?
Tryptophanase - which breaks down tryptophan into indole, pyruvic acid and ammonia.
If indole is present and Kovac's reagent is added what will occur?
A positive reaction of a red ring forming at the top of the medium or broth.
If indole is not present and Kovac's reagent is added what will occur?
A negative reaction of an amber or greenish ring at the top of the medium or broth.
What are the modes of transmission of infectious diseases?
1. Skin to Skin Contact (Cold Sores)
2. Body Fluids (Mono)
3. Air (Sneezing/Coughing/Influenza)
4. Fomites (Cellphones/Door Handles)
5. Oral/Fecal (E.Coli)
6. Arthropage Vector Borne (Tick: Lyme Disease)
7. Transplacental (Syphillus)
What is the importance of the aseptic technique?
A universal technique used in laboratories to prevent the contamination of the work area, helping transfer organisms without contaminating the surrounding areas.
What is a broth medium?
A liquid medium containing all the nutrients that a bacteria can utilize for growth.
Where do you label a Petri plate?
A small notch on the corner. with your initials, station number, and bacteria used.
In acid fast staining, what is the name of the coating that protect the cell wall from stain penetration?
Gram Positive Bacteria
1. Thick PTG wall (30 layers)
2. Susceptible to Penicillin
3. Susceptible to Lysosomes
4. Purple stained
Gram Negative Bacteria
1. Thin PTG wall (2-3 layers).
2. Not susceptible to penicillin
3. not susceptible to lysosomes
4. Red stained
What is the purpose of immersion oil?
Prevents the loss of light rays due to diffraction and improves resolution.
What is resolving power?
the ability to distinguish two points as distinct, separate objects rather than one blurred image.
List three bacteria and diseases caused by endospore forming bacteria.
Clostridium tentai - Tentus
Clostridium Botulinum - Botulism
Bacillis Anthraces - Anthrax.
What is the difference between a negative stain and a capsule stain?
A negative stain is a one step process in which the background is stained instead of the organism.
A capsule stain stains the protective coating of the bacteria agains the negative background stain.
List the bacteria and diseases caused by bacteria that possess capsules.
S. Pneumonia - pneumonia, meningitis, otitis media
E. Coli - UTI, diaherria, gastroenteritis.
K. Pneumonia - pneumonia
N. meningitis - meningitis
Name the primary and counter stain in the acid fast stain.
Primary - Carbolfusin
Counter - Methyl Blue
List all the reasons for studying biochemical characteristics of bacteria.
It allows us to identify genus and species.
What is the function of broth media?
-liquid at room temp and incubation temp
-beef bouillon (beef extract, peptone, and water)
-nutrient broth (urea)
What is the function of the semisolid media?
-jelly like consistency
-too soft to form a slant, but more solid than a broth
-SIM medium contains beef extract, peptone, peptonized iron, sodium thiosulfate and 3g of agar
-3-5g/L of agar
What is the function of the solid media?
-solid at room temperature and normal incubation temps
-15g/L of agar
-agar deeps, slants (TSA slant), and plates are options
What is difference between solid and semisolid?
-solid has 15g/L of agar
-semisolid has 3-5g/L of solid
What is the difference between complex and chemically defined medium?
-complex: contains organic components; most medias used in lab
-chemically: contains inorganic chemicals like glucose, Simmon's citrate agar
-clear solution is forced through a membrane that contains 0.2micron pores
-filters all bacteria but not viruses
-urea broth is sterilized this way
-ethylene oxide is used for things that would melt in the autoclave
-IV tubing, catheters, etc
-heating of glass or metal to 160-170 C for 2+ hours
-not satisfactory for paper or liquid products
Common Temps (freezing point of water, room, incubator, body, boiling water at room temp and autoclave at 15psi)
water freezes: 0 C & 32 F
room temp: 22-25 C & 71.6-77 F
incubator: 30-37 C & 86-98.6 F
body temp: 37 C & 98.6 F
water boils: 100 C and 212 F
water boils at 15psi: 121 C and 250 F
-eye piece 10X
-oil immersion 100X
total mag= eye piece x objective
1000X = 10X x 100X
Condenser adjustment knob
condenser should be on "O" for bright; the adjustment knob controls the height of condenser btwn stage and light source
What does parfocal mean?
One a specimen has been focused on in 10x the microscope has the ability to switch to higher magnification with a minimum focal adjustment.
lens' ability to distinguish between two separate points. smaller the resolving power is the better the lens
What are the typical bacteria arrangements?
Staphylo - a cluster of bacteria
Strepto - a chain of bacteria
Tetrad - a square cluster of bacteria
Sarcina - a stack of square cluster bacteria.
-rod shaped bacteria that forms chains
-found in soil
-arborescent TSA slant
subjective criteria a patient uses to describe their disease state (headache, pain, fatigue)
a disease that spreads from one host to another by direct OR indirect means (ie: cold or flu)
Common source epidemic
the sudden increase in the number of individuals infected by a specific disease followed by a rapid decline in the number of cases (food poisoning...not contagious)
slow, gradual increase in the number of individuals infected by a specific disease agent followed by a peak and then a slow decline in the number of cases. Disease is contagious...measles, chicken pox
organism or object that provides a pathogen with living conditions until it can transmit (bird carrying west nile)
insect that transmits a disease from host to host (mosquito transmits west nile)
fecal-oral transmission: food poisoning and intoxication
airborne transmission: spread of agents more than 1m from source (TB and measles and cold)
different than airborne; involves the droplet to be expelled less than 1m from source (flu and measles)
What elevations can a bacterial colony have?
Umbonate (looks like a fried egg)
What margins can a bacterial colony have?
Curled (curdled apperance)
Lobate (big lobes)
What consistency can a bacterial colony have?
Dry - ground glass appearance
Matte - flat paint look
Shiny - glossy
Mucoid - moist
What qualities of the skin protect from infection?
high salt content (sweat), low pH (acidity), fatty acid covering by sebaceous gland, and lysozyme secretion from sweat gland
Who is the father of antiseptic surgery and what did he do?
Joseph Lister and he used carbolic acid (phenol) to prep surgical sites
What is MRSA and where is it found?
Methicillin resistant Staphylococcus aureus & found in nasal passage
What are the temperature bacteria classifications?
psychophiles: frigid, -5-20 C
psychotrophs: grow 0-30 C; food spoilers
mesophiles: 20-45 C; human pathogens
thermophiles: 40-60 C; hottt
What is subculturing and what else is it called?
transfer organism from one medium to another; inoculation
What does asepsis mean?
without organism; so it what we want in aseptic technique so there is no contamination
How do you grow pure colony?
streak plate to grow single colony; TSA slant to grow that pure colony; gram stain to test for purity
What is the inoculating needle or loop for?
needle: from a slant or broth to deep
loop: to make a streak plate
(either is good to transfer TO broth)
-tetrad of cocci
-BRIGHT yellow colonies on TSA plate
-TSA slant = filiform
-broth = sediment
-random arrangement of small rods
-TSA slant will turn GREEN from pyocyanin but colony will be pinkish
-AEROBIC and MOTILE
-corn tortilla smell
-random arrangement of rods
-bright red from prodigiosin
-found on bread
-turbid in broth
-TSA slant = echinulate
Simple vs Differential stain
S: one dye for all cells
D: more than one dye to differentiate cells (gram, endospore, acid staining)
Fresh samples for gram staining are important why?
The gram + cells wall will deteriorate and make the cell appear gram -
Spore location in cell
central endospore = center
terminal endo= one of the cell's poles
subterminal endo= off center