Cultivation and identification Flashcards
culture media
various nutrients used to grow bacteria
broth
water based liquid culture that do not solidify above freezing point
Agar
solid culture media that provides a firm surface on which cells can for a discrete colonies
liquifies at boiling point
resolidifies at 42 degrees celsius
synthetic
chemically defined, pure composition is known
maintains a particular nutrients in order ensure optimal growth (expensive)
nonsynthetic
exact composition unknown, meat, veggies, tissue infusions, vary from batch to batch, ingredients are present but not precisely defined, used by fastidious mos
general all purpose media
supports growth of broad spectrum microorganisms
enriched media
supports growth of mos by addition of growth supplement
selective media
suppresses growth of unwanted bacteria and encourages the growth of wanted bacteria
differential media
distinguish between various genera or species of different microorganisms by color changes or other morphological characteristics
enrichment media
designed to increase very small numbers of desired mos to detectable numbers, uses selective agents and light elevated temperatures
reducing media
contains an agent that absorbs oxygen or slows the penetration of oxygen in a medium
transport media
used to keep fragile microorganisms stable until sent to the lab (doesnt change it just keeps it from dying)
(at medical campuses)
streak plate
increasingly dilutes population, to help determine how many colonies there are
pour plate
used for food samples
used for anaerobes and microaerophobic organisms
used for milk and food colonies
resolving power
the ability to see two objects as seperate and distinct
total magnification 1500X
light becomes diffracted
numerical aperature
represents the angle of light produced by refraction and is a measure of the quantity of light gathered by the lense
bright field
most common multipurpose microscope
dark against white background
normally have 3 or 4 objectives
objective lense
magnifies the real image of the object (real image)
ocular lense
near the eye, magnifies the virtual image
darkfeild
white against black background
special disc blocks out all light besides peripheral light
phase contrast
special condenser and objectives are used which alters the light as it passes through and around the specimen
differential interference contrast (DIC)
same as phase contrast but has additional prisms that add contrasting colors to the image and 2 beams of light instead of one
produces well defined images that are colored
fluorescense
uses fluorochrome dye with conjugated Ag-Ab complexes
used for myobacterium TB screening
uses UV and lenses
referred to as immunoflorescense
electron microscope
5000-100000X+ uses electrons and magnetic fields TEM (transmission electron microscope) SEM (scanning electron microscope) Used for viruses
wet props view
motility (organism is living)
dry props view
structure/shape (organism is dead)
procedure for preparing broth
drop on slide, air dry, heat fix
procedure for preparing agar
drop of sterile water, saline, broth, air dry, heat fix
dye
colored organic compounds used to stain microbiological specimens in order to enhance the contrast between the mo and the background
chromophore
charged color portion of the dye
basic dyes
used to stain cell components
positive charde
MB,CV,Safranin
acidic dyes
used to stain background
negative charge
eosin, nigrosin, india ink
procedure for simple staining
apply stain to air dried heat fixed slide leave on for a few seconds to 2 minutes rinse with water dry in blotting book MB,CV,CF, safranin
gram stain
uses chemical composition of cell wall
differences in thickness in charge concentration
hans christian gram- 1884
stains in the gram stain
primary stain= crystal violet mordant= iodine decolorizer= alcohol or acetone counterstain= safranin
acid fast or ziehl neelsen
stronger more aggressive staining procedure because of waxes and lipids in cell walls
stains in dye in the acid fast/ziehl neelsen
primary stain= carbol fuchsin
mordant= heat
decolorizer= acid alcohol
counterstain= methylene blue or bright green
positive acid fast =
pink
not acid fast =
blue or green
spores =
green
vegetative cells =
red
endospore stain
similar to acid fast
describe the procedure for structural staining
stain background with india ink or congo red
determine presence of capsules
used for cryptococcus neoformans
used to reveal overall shape and arrangement of mo and other structures
flagella stain
leifson stain
spore stain
shaeffer fulton endospore stain
metachromatic granule stain
stains granules different shades
pigmentations
water soluble (Pseudomonas) non-water soluble (Serratia)
morphology
elevation, form, margin, consistency
optical properties
translucent, transparent, opaque
turbidity
cloudiness
pellicle
surface film
sediments- precipitates
dense clumps or clusters of mos
