MALDI-TOF and sensititre Flashcards
what is MALDI-TOF MS?
laboratory equipment for accurate and rapid ID of bacteria and fungus from clinical specimen and other sources
how does MALDI-TOF SM work?
an ionization technique that uses a laser energy absorbing matrix to create ions from large molecules with minimal fragmentation
in relation to MALDI-TOF what is laser-infrared?
provides high intensity pulsed energy to the analyze on the target, allowing it to desorb and ionize an instant without thermal decompensation
what is the time of flight?
time required to travel a distance through a medium
what does MALDI measure in bacteria?
measures highly abundant proteins found in microorganisms
how does MALDI-TOF work?
compared spectra of analyzed organisms proteins from unknown organisms contained in the MALDI-TOF MS database
what are the reagents needed for MALDI-TOF
-target plate
-toothpicks
-target position map
-HCCA matrix: lyses bacterial cell wall
-BTS (bacteria test standard): calibration and quality control
MALDI-TOF steps for bacterial ID
-collection of clinical sample
-sample submission to clinical lab for culture and ID
-culture set up and incubation
-examine for growth on plates
-if culture is pure then proceed with MALDI-TOF
what are the types of extraction methods for MALDI
-direct smear
-formic acid extraction
-tube extraction
what can cause no organism ID on MALDI
-organism not in MALDI database
-too much bacterial cells on target plate
-not enough bacterial cells on target plate
-reagent failure
-no peaks found (technical error)
what is sensititre test
lab equipment used to perform antimicrobial (drug) susceptibility tests based on principles of MIC values
T/F antimicrobials with low MIC’s are more effective than those with high MIC’s
T
-only a low dose is necessary to eradicate the microbe causing the disease
