Microscopic examination of Infected materials Flashcards
who established the germ theory of disease?
Robert Koch
developed the Gram stain (allows us to examine a pus specimen directly for the gram-positive Staphylococcus
Christian gram
If sample can ONLY be collected through swabs, submit how many swabs?
Two
swab is rolled ?
back and forth
swab is ____ in specimen for several seconds and use to prepare a _____
immersed; thin spread of material
opaque material means ?
it is spread thinly
What are the steps to prepare smear from thick, granular, or mucoid material?
1) Place a portion of the sample on the labeled slide, and
press a second slide, with the label down, onto the
sample to flatten or crush the components.
2) Rotate the two glass surfaces against each other so that
the shear forces break up the material.
3) Once the material is flattened and sufficiently thinned, pull
the glass slides smoothly away from each other to
produce two smears.
4) If the material is still too thick, repeat the first three steps
with another (third) glass slide. The best smear or both
smears can be retained for staining.
thin specimens should be ?
dropped and not spread
what are the examples of thin specimens?
urine, csf, and transudates
what is the preferred type for thin fluids
cytocentrifugation
fluid should NOT be spread over a larger area of the slide,
UNLESS
Turbid
excellent method for preparing non viscous fluids such as
CSF and bronchoalveolar lavage fluids
cytocentrifuge prep
imparts an artificial coloration to the smear materials that allows them to be inspected using the
magnification provided by a microscope
staining
it colors the form and shapes presents and one of the example is methylene blue
simple stains
it colors the specific components presents and examples are gram stain and acid fast stain
differential stain
use in identification of an organism
probe mediated stains
available stains in ALL diagnostic microbiology laboratory
Gram, acid-fast, calcofluor white, and rapid modified wright giemsa
For wet prep in micro examination what type of specimen is use
fluids or semisolids
for cytocentrifuged what type of specimen is use
clear or slightly turbid
for smear drop prep what type of specimens are used
pus or fluid, tissue homogenate, and swab rinse
for smear pellet what type of specimens are use
blood culture and dilute specimen
for smear rolled what type of specimen is used
swabbed material
for smear imprint what type of specimen is used
tissue
a differential stain that allows to distinguish 2 major groups of bacteria while visualizing the morphology and
cellular arrangement of the organisms.
gram staining
Crystal violet is rinsed too vigorously. what is the effect?
Poor or no staining or gram (-) organisms
Decolorization is prolonged. what is the effect or outcome?
G (+) complex will be removed.
G (+) organisms will not stain
Decolorization is insufficient. what is the effect or outcome?
Organisms may be falsely (+)
Prolonged exposure to
safranin. what is the effect or outcome?
Gram (+) will be leached from
(+) cells
Insufficient exposure to safranin. what is the effect or outcome?
Failure to stain G (-) bacteria & background materials
uses heat to drive primary stain into the cell wall
ziehl-neelsen
use for identification of mycobacterium spp.
acid fast stain
uses detergents to drive primary stain into the cell wall
kinyuon
examination of specimens should begin with?
gross visual inspection
is the fastest and least expensive method for presumptive diagnosis in these common clinical settings.
simple gram stain or acid fast stain
Organisms are readily seen because more than?
105 colony-forming units
type of infection that are easily recognized by microscopy and only required limited interpretations
monomicrobial
disease related to streptococcus pneumoniae
pneumonia
disease related to staphylococcus aureus
abscesses or pyodermas
disease related to clostridium perfingers
gas gangarene
disease related to nocardia spp.
lung abscesses
If acid-fast bacteria are suspected, the acid-fast
stain should be performed _____
before an opinion is rendered
If a fungal element is not clearly gram-positive, what stain should be performed
calcofluor stain
Purulence with red blood cells, neutrophils, protein
background, and necrosis reflects
acute inflammation
Mononuclear cells, including lymphocytes, monocytes,
and macrophages, reflect
chronic inflammation
for scoring sputum
bartlett’s method
method for contamination assessment document
murray-washington
emphasizes the ratio between SECs and PMNs.
heineman’s method
