Matrix-assisted laser desorption ionization-time of flight mass spectrometry for the identification of bacterial and fungal isolates

Identification of bacterial and fungal isolates from clinical specimens has traditionally been performed by examination of colony morphology and by biochemical characterization using classic tube sets. While these methods remain the gold standard for identification, they can be laborious to perform and subjective to interpret. These drawbacks have largely been alleviated with the advent of automated biochemical testing platforms and with the development of DNA sequencing and polymerase chain reaction techniques. Though reliable and rapid, molecular-based platforms are associated with significantly higher cost and require advanced user expertise for assay development and performance. These factors limit the routine implementation of molecular diagnostic methods to large hospitals and reference laboratories. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is an automated, molecular platform recently adopted by many clinical laboratories worldwide, which offers a rapid, straightforward, and inexpensive method for the identification of bacterial and fungal organisms.