Matrix‐Assisted Laser Desorption/Ionization Time‐of‐Flight Mass Spectrometry and Proteomics: A New Era in Anaerobic Microbiology

Abstract

Genome sequence data provide a framework for predicting potential microbial activities; however, the proteome content of the cell dictates its response to its environment. Microbiology is witnessing a major initiative to elucidate the nature of the proteome of large numbers of species. The tool driving the proteomic revolution is matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. During the analysis process, proteins are ionized and separated on the basis of their mass-to-charge ratios, which results in a characteristic mass-spectral profile. Because of the dynamic nature of the cell and the large number of external parameters that could influence its mass-spectral profile, considerable work was needed initially to optimize sample analysis and obtain consistent and reproducible results. For many anaerobes that grow poorly or are nonreactive in most diagnostic systems, proteome analysis is likely to have a major impact on microbial diagnosis and the delineation of centers of diversity associated with infections.

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

“…MALDI-TOF MS has also been utilized to evaluate subsets of anaerobic microorganisms isolated from defined biological niches. The applicability of this method for routine identification of important human-pathogenic anaerobic bacteria was evaluated by Shah et al, who showed that through the use of intact-cell MALDI-TOF MS, Porphyromonas strains could be differentiated (243). Nagy et al reported 97% accuracy at the species level for 277 isolates and 9 species of Bacteroides (244).…”

The value of MALDI-TOF MS for the identification of clinically relevant anaerobic bacteria in routine laboratories

“…A retrospective study by Eigner et al (2009) on more than 1000 routine isolates representing the main bacterial groups encountered in a clinical microbiology laboratory showed 95.2 % correct identification by MALDI-TOF MS, whereas Seng et al (2009) showed that out of 1660 clinical isolates representing 109 different species, they could identify correctly only 84.1 % at the species level. Shah et al (2002) predicted that MALDI-TOF MS would bring a new era in anaerobic microbiology. Several studies have been carried out since then, and the results of different reports demonstrate that superior identification of anaerobic bacteria can be achieved using MALDI-TOF MS for anaerobic isolates in routine laboratories (Justesen et al, 2011;La Scola et al, 2011;Veloo et al, 2011;Wybo et al, 2012).…”

Use of surface‐enhanced laser desorption/ionization ‐time of flight to explore bacterial proteomes

“…These papers mainly describe the use of the ProteinChip Arrays with purified proteins [10][11][12][13][14], or extracted surface proteins [15][16][17][18][19]. A few reports are available in the literature in which this technology is used with protein extracts [20][21][22]. We are primarily interested in the study of Streptococcus pneumoniae and its response to antibiotic treatments.…”

“…Even in the microbiology field, under certain conditions, only limited sample quantities are available (this work, [22]). A technology like SELDI-TOF, with adequate sensitivity to generate data from minimal starting material, is very valuable in such cases.…”

“…We believe these results show the appropriateness of the ProteinArray technology for the study of bacterial proteomics alone or in combination with 2-DE or other technologies. Furthermore, it could be used for microorganism protein profiling and possibly for microorganism identification as suggested in [22]. This kind of application would require the generation of a vast database of spectral profiles to allow for the individuation of species-specific peaks.…”