module 10 pt 2 Flashcards
what is biosafety 1
used in teaching laboratories
barrier protection (cloves, coat, safety glasses)
what is biosafety 2
moderate risk pathogens
barrier protections + manipulations that might generate aerosols must be performed in a biological safety cabinet
biosafety 3
emerging and high risk pathogens
barrier protection
negatively pressurized lab fitted with filters to prevent pathogen escape
safety cabinet for manipulations
biosafety 4
emerging and high risk pathogens, especially those spread by aerosols, for which there is no treatment, cure, or vaccine
barrier protection
manipulations must be performed in a sealed safety cabinet and by personnel wearing positive pressure suits fitted with an air supply
what are some pathogens that can be identified by microscope
neisseria gonorrhoea
tuberculosis
what are the two types of identifying microorganisms by culture
general purpose media
enriched media
what is general purpose media
support growth of most aerobic or facultatively aerobic organisms
blood agar
what is an enriched media
contain specific growth factors that enhance growth of certain pathogens
what is a selective medium
restricts the growth to a particular phenotype of interest
ex. MB inhibits gram positive so we can only see gram negative
what is a differential medium
does not restrict growth but permits the identification of a particular phenotype
ex. distinguishing
what do you do to assess sugar fermentation
differential media
what are miniaturized media kits
kits that allow rapid identification of clinical isolates by running multiple tests on the specimen at the same time
how can urinary tract pathogens be cultured
using general purpose media, selective media
what is the Thayer Martin medium used for
to culture neisseria gonorrhoea
its a selective medium that contains antibiotics that inhibit the growth of other bacteria
what is genital specimens non selective medium
chocolate agar
what can be used to determine if neisseria gonorrhoea is present
direct microscopic examination (can be detected for males)
non selective enriched media like chocolate agar
selective medium like Thayer Martin
what is PCR used for
a diagnostic
what is quantitative PCR
to quantify the amount of DNA or RNA in a sample
it generates an amplification curve that shows an increase in fluorescence as PCR progresses
what is qualitative PCR
used to detect the presence or absence of a specific DNA sequence in a sample
it exploits nucleotide polymorphisms and compares the patients sample to the pathogens DNA to determine which pathogen has infected the individual
what is serology
the study of antigen-antibody reactions in vitro
what is skin testing
methode for determining exposure to a pathogen
can all pathogens always be seen in skin testing
no
what is a precipitation reaction
an antibody antigen reaction leading ti the formation of a visible precipitate
what is passive/indirect agglutination
antigens of interest are also soluble so they need to be absorbed by a carrier and then put together
bound to red blood cells (carrier cells)
direct agglutination
soluble antibodies binding to soluble antigens that are bound to the surface of cells
what is sensitivity also called
true positive rate
what does sensitivity (true positive rate) refer to
the ability of a test to correctly identify individuals who have a disease or condition
specificity means what
the ability for a test to correctly identify individuals who do not have a disease or condition
what is specificity also called
true negative rate
is direct or indirect agglutination more sensitive
Indirect
what is direct agglutination usually used for
classification of the antigens found on the surface of red blood cells
where can neutralization reactions happen
in vivo or in vitro
what does chemically modifying antigens with fluorescent dye do
can help detect antigens on intact cells
what test mechanism has high specificity and sensitivity
fluorescent
what is an EIA
general term referring to any immunoassays that uses an enzyme linked system to detect the presence of a target antigen or antibody
ELISA
specific type of EIA used to detect amounts of soluble antigens and antibodies in samples
whats specific about ELISA
particular assay format
solid phase (microplate) to immobilize the antigen or antibody
where is body fluid applied on a rapid test
support matrix
when does a color form in rapid tests
concentration of chromophore gets high enough
what is immunoblot
isolation of protein, then transferred to a membrane where specific antibodies are then added for detection
