MALDI-TOF mass spectrometry in the 21st century clinical microbiology laboratory

MALDI-TOF mass spectrometry has become a reference method for the routine identification of bacterial isolates in clinical microbiology laboratories around the world. Its high specificity, user-friendliness and cost-efficiency, together with its ability to provide reliable results in less than 5min have favoured its implementation and further development. The amount of microbial species that can be identified by MALDI-TOF routinely has increased in the last few years and now it is possible to reliably identify non-tuberculous mycobacteria or closely-related species of Nocardia spp. Yeasts, both belonging to Candida and non-Candida genera can also be identified by MALDI-TOF, as well as filamentous fungi. In the latter case, both sample preparation methods and the available databases have been important factors in achieving accurate identifications at the species level. The expertise acquired over time has allowed researchers to identify microorganisms directly from clinical samples, facilitating improved management of infected patients. This expertise has also been applied to the development of a MALDI-TOF-based methodology for the detection of different antimicrobial resistance mechanisms. Therefore, future applications such as bacterial strain typing, or the detection of virulence markers seems feasible to perform with this technology. Furthermore, other emerging mass spectrometry and spectroscopy technologies may assist MALDI-TOF in the near future to carry out important tasks that nowadays are performed by time-consuming and labour-intensive methods.