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MALDI in Microbiology

Until recently, clinical diagnostic laboratories predominantly relied on conventional phenotypic ways of diagnosing infections, and sometimes on gene sequencing techniques.…

Until recently, clinical diagnostic laboratories predominantly relied on conventional phenotypic ways of diagnosing infections, and sometimes on gene sequencing techniques. MALDI-TOF mass spectrometry generates specific mass spectral fingerprints, which can be seen as a matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry which has entered quotidian microbiological practice.

unique signatures or microorganisms that may assist in their accurate identification to the genus and species levels – with solid potential to be employed for strain typing.

Bacterial Identification

Several approaches for utilizing MALDI -TOF mass spectrometry are now being used in microbiological diagnostic laboratories. One approach compares results to databases of commercially available mass spectrometry signatures to identify the sample bacteria, and a second uses a proteome database to identify biomarker masses in the bacteria from sequenced genomes. De tweede bioinformatica-aanpak maakt het mogelijk om variatieverschillen in cultuurgroei en voorbeeldbehandelingsomstandigheden, terwijl het eerst bijzonder nuttig is in routinematige laboratoriummethoden, zoals diagnoses, en kan onderscheiden tussen species en subspecies.

Gezien zijn nauwkeurigheid kan de technologie ook worden directly applied to various clinical samples, most notably blood, cerebrospinal fluid, urine, pleural fluid, and peritoneal fluid. The major restraint is the amount of bacteria present in the samples, due to the detection limit of current MALDI-TOF protocols. To bypass this drawback, large volumes are usually required for blood and urine samples, as well as using cultures as an additional enrichment for blood.

Results observed for bacterial identification with MALDI-TOF mass spectrometry using either of the two aforementioned approaches,

One of the main advantages of employing MALDI-TOF technology for identifying bacteria is the rapid availability of results, which are typically ready in less than an hour. Additionally, MALDI-TOF mass spectrometry allows for accurate identification of a large diversity of bacteria that have scarce phenotypic traits and that necessitated 16S rRNA gene sequencing before the MALDI-TOF era.

Fungal Identification [19659004] MALDI-TOF mass spectrometry was quickly and successfully attuned for the identification of fungi. Voor nu is deze methode voornamelijk gebruikt voor de routine gistidentificatie, terwijl verdere ontwikkeling nodig is (namelijk in voorbeeldpreparatieprotocollen en databasebibliotheken) om deze identificatiebenadering te gebruiken voor andere groepen van schimmels (zoals dermatophytes en filamentous schimmels) .

Akin to the situation with bacteria, misidentification or non-identification of fungal genera and species by MALDI-TOF mass spectrometry is essentially due to errors, absences or incomplete reference spectra in databases.

Furthermore, the spectral signal pertinent to filamentous fungi depends on fungal phenotype – which includes basidiospore, fruiting body, surface mycelium and substrate mycelium. In addition, when grown on agar plate, vegetative mycelium shows manifold zones that correspond to distinct ages or stages of development. Dit kan resulteren in misidentificatie en zo variabele resultaten van hetzelfde monster, daarom is het essentieel dat databases een grondige database bevatten van meerdere MS fingerprints van verschillende ontwikkelingsstadia van filamentous schimmels om te zorgen voor correcte identificatie.

Accuracy, Time and Cost effectiveness [19659004] When compared to conventional methods for microbial identification, MALDI-TOF mass spectrometry in a majority of cases confers a substantial gain of both engineer / technician working time (preparation samples) and turnaround time (obtaining results with automated analytical procedure). [19659002] However, the purchase of MALDI-TOF mass spectrometry instrument is undoubtedly one of the most expensive capital investments for the clinical microbiology laboratory. [19659000] Applications

MALDI-TOF MS is used in a variety of industries, including biopharmaceuticals, organic chemistry, metabolomics, and other chemicals. genomics, as well clinical and diagnostic and treatment applications. In organic chemistry applications, MALDI-TOF is used to analyze nucleic acid, protein and polymer masses, as well as identify complex mixtures of oligonucleotides and small proteins, supplying biochemical and chemical researchers with useful information. MALDI-TOF MS plays a crucial role in the advancement of rapid patient diagnosis and improved health outcomes. A prime example of this is its use in routine classification of microorganisms in patient samples for clinical microbiology.


In conclusion, MALDI-TOF mass spectrometry is a fascinating novel technology for microbiële identificatie die snel, efficiënt, kostend en eenvoudig in gebruik is. Soon this instrument will be pervasive in diagnostic laboratories as, despite significant cost of the instrument and its maintenance, consumables and running costs are much lower when compared to conventional methods.

Reviewed Chloe Barnett, BSc [19659012] Further Reading

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