What can MALDI-TOF tell us?
MALDI-TOF MS in Bacteriology
A number of researchers have shown that MALDI-TOF MS can be used for early identification of bacteria in blood cultures, urinary tract infections (UTIs), cerebrospinal fluids, respiratory tract infections, stool samples etc.
What does MALDI-TOF MS detect?
Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) has become a widely used technique for the rapid and accurate identification of bacteria, mycobacteria and certain fungal pathogens in the clinical microbiology laboratory.
What is a MALDI score?
MALDI-TOF MS identifications were classified using modified score values proposed by the manufacturer: a score value ≥2 indicated species identification; a score value between 1.7 and 1.9 indicated genus identification, and a score value <1.7 indicated no identification.
What molecule does MALDI-TOF identify?
After the matrix solution air-dried, the spotted samples were analyzed by MS (Jeong et al., 2013, 2014). MALDI-TOF MS has also been shown to be useful for detection of protein toxins, such as staphylococcal enterotoxin B, botulinum neurotoxins, Clostridium perfringens epsilon toxin, shiga toxin etc.
How does MALDI-TOF identify proteins?
One of the main uses of MALDI-TOF-MS is in the identification of proteins, by peptide mass fingerprinting (PMF). Here we describe a simple protocol that can be performed in a standard biochemistry laboratory, whereby proteins separated by 1D or 2D gel electrophoresis can be identified at femtomole levels.
Is MALDI-TOF accurate?
MALDI-TOF MS demonstrated high accuracy for the direct identification of pathogens from urine samples, with a pooled sensitivity of 0.85 and a pooled specificity of 0.93.
How accurate is MALDI-TOF?
The MALDI-TOF MS correctly identified 92% of the M. tuberculosis isolates (95% CI of 0.87 to 0.96), and 68% of M. bovisisolates (95% CI of 27% to 100%) to the species level. Mycobacterium tuberculosis complex in solid media with reference strains using augmented database showing more accurate identification.
How many organisms can MALDI-TOF identify?
For Gram-negative bacteria evaluation, there are 2263 clinical significant species can be analyzed by MALDI-TOF MS identification.
How do you calculate mass in MALDI-TOF?
TOF is a field-free flight tube. The ions travel in a strait and linear direction to the detector. The mass to charge ration (m/z) of the sample ions can be calculated using the equation T= C1(m/z)0.5 +C2.
What is the limitation of MALDI-TOF?
The most significant limitation of MALDI-TOF is its low analytical sensitivity without prior cultivation and the discrimination of phyletically related microorganisms such as Shigella and Escherichia coli [41] Consequently, MALDI-TOF is unsuitable for detecting the small number of bacteria in sterile samples.
What are limitations of MALDI-TOF?
Is MALDI-TOF quantitative?
MALDI-TOF MS has been applied by several groups to relative quantitative measurements. At the same time, the non-quantitative character of this method has been widely reported.
Is MALDI-TOF a molecular method?
Molecular and MALDI-TOF
Molecular techniques can generate results and positive identifications remarkably quickly; so can Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) mass spectrometry, which is having a significant impact on clinical microbiology.