Use of MALDI-TOF for Diagnosis of Microbial Infections

Although mass spectrometry is making its mark on all facets of clinical laboratory medicine, arguably no field is witnessing its impact more than clinical microbiology. The application of MALDI-TOF mass spectrometry (MALDI-TOF MS) to microbial identification is revolutionizing clinical microbiology by providing rapid identification with minimal sample preparation at a potential savings in costs. Across the globe, the degree of implementation of MALDI-TOF MS varies markedly. In Canada, Australia, and much of Europe, MALDI platforms are in routine use in clinical microbiology, whereas the US Food and Drug Administration has yet to provide clinical clearance. In this Q&A, 4 experts from across the globe with first-hand experience implementing MALDI-TOF MS in the microbiology laboratory provide insight into what this technology can and cannot provide, what it takes to bring it in house, and what direction it takes us in the future.The application of MALDI-TOF MS to the diagnosis of microbial infections has been touted as a revolution in clinical microbiology. However, no technology is without its pitfalls. Can you please describe what you feel are the greatest strengths and limitations of MALDI-TOF MS? Gilbert Greub: When it is used to identify bacterial strains and fungi, the main strengths of MALDI-TOF MS are the rapidity of the technique ( 95% accuracy at the species level. One of the most important limitations of this technique is its relatively low analytical sensitivity (about 105–106 bacteria/well). Thus, the accuracy of the identification is increased when the identification is done on a colony grown on agar or on a blood culture pellet, i.e., after a culture-based amplification step. Consequently, MALDI-TOF MS is not a tool currently suitable to detect …