Term
|
Definition
is sample pathogenic?
specific treatment
epidemiology data stored and shared |
|
|
Term
|
Definition
liquid vs solid media
electrolytes/blood/peptone/NaCl/water
solid always with agar
can add selective compounds |
|
|
Term
|
Definition
detection of metabolised substrates
detection of enzyme markers
immunological - use of antibodies
metabolic substrates - glycosidases - produced by bacteria ex strep |
|
|
Term
| problems with measuring metabolic substrates |
|
Definition
not many naturally chromogenic by products existing
media must be highly batch producible
media must be basic as possible to reduce cross reactivity |
|
|
Term
|
Definition
not many natural substrates available
easy
more sensitive
useful for confirmation
expensive
ecoli |
|
|
Term
|
Definition
quick and cheap
gram stain
can't be used on mycobacteria - acid-fast used |
|
|
Term
|
Definition
relies on AB-AN complexes
hundreds of types of antibodies generated towards one species
highly sensitive vs highly specific |
|
|
Term
|
Definition
staph aureus
fibrin clot produced when enzyme complexes react with thrombin like molecules in the plasma |
|
|
Term
|
Definition
uses indirect method
automated
can be reversed - use antibody to bait antigen
can do hundreds at a time |
|
|
Term
|
Definition
faster
less bias
larger scale
reduces human error
can be used for susceptibility testing
Vitek-2
MALDI-TOF |
|
|
Term
|
Definition
99 different tests at a time
£20 per time
few hours
requires monoculture
susceptibility testing too |
|
|
Term
|
Definition
10 minutes
96 tests per time
bacteria proteins vaporised and ionised and fired through detector and spectra compared to database
seperation based on charge and mass
all bacteria have a unique proteomic fingerprint |
|
|
Term
|
Definition
important for predicting in vivo response
disc diffusion
simple cheap reliable
organism applied evenly to surface
filter paper containing specified conc of known antibiotic applied to field
antibiotic diffuses into agar
zone of inhibition or no change
doesn't always mean sensitivity
zone used to calculate MIC
most problems usually from lab handling |
|
|
Term
|
Definition
minimum inhibitory conc
lowest conc that will inhibit growth
confirms unusual resistance
antibiotics serially diluted + tested - can be agar or broth |
|
|
Term
|
Definition
Minimum bacerial conc
lowest conc of antimicrobial that will be bactericidal to more that 99.9% of the culture |
|
|
Term
|
Definition
Measure MIC
test resistance more than susceptibility
antimicrobial gradient absorbed onto marked strip
placed on field of bacteria
exact conc growth is inhibited can be read from strip |
|
|
Term
| automated susceptibility testing |
|
Definition
measure mic breakpoints
used dehydrated conc of antibiotics
no good on direct samples like blood |
|
|
