Ribosomal proteins as biomarkers for bacterial identification by mass spectrometry in the clinical microbiology laboratory

• Published in: Journal of microbiological methods Vol. 94; no. 3; pp. 390 - 396
• Main Authors: Suarez, Stéphanie, Ferroni, Agnès, Lotz, Aurélie, Jolley, Keith A., Guérin, Philippe, Leto, Julie, Dauphin, Brunhilde, Jamet, Anne, Maiden, Martin C.J., Nassif, Xavier, Armengaud, Jean
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2013
• Subjects: Bacteria; Bacterial Proteins - analysis; Bacterial Proteins - chemistry; Bacterial Proteins - classification; Bacterial Typing Techniques - methods; Biomarkers; Biomarkers - analysis; Biomarkers - chemistry; Cluster Analysis; Databases, Protein; Humans; Mass spectrometry; matrix-assisted laser desorption-ionization mass spectrometry; Meningitis, Meningococcal - microbiology; microorganisms; Models, Biological; molecular weight; Neisseria meningitidis; Neisseria meningitidis - chemistry; Neisseria meningitidis - isolation & purification; nucleotide sequences; Phylogeny; rapid methods; Ribosomal proteins; Ribosomal Proteins - analysis; Ribosomal Proteins - chemistry; Ribosomal Proteins - classification; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Biomarkers; Neisseria meningitidis; Ribosomal proteins; Mass spectrometry
• ISSN: 0167-7012; 1872-8359; 1872-8359
• DOI: 10.1016/j.mimet.2013.07.021

Whole-cell matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a rapid method for identification of microorganisms that is increasingly used in microbiology laboratories. This identification is based on the comparison of the tested isolate mass spectrum with reference databases. Using Neisseria meningitidis as a model organism, we showed that in one of the available databases, the Andromas database, 10 of the 13 species-specific biomarkers correspond to ribosomal proteins. Remarkably, one biomarker, ribosomal protein L32, was subject to inter-strain variability. The analysis of the ribosomal protein patterns of 100 isolates for which whole genome sequences were available, confirmed the presence of inter-strain variability in the molecular weight of 29 ribosomal proteins, thus establishing a correlation between the sequence type (ST) and/or clonal complex (CC) of each strain and its ribosomal protein pattern. Since the molecular weight of three of the variable ribosomal proteins (L30, L31 and L32) was included in the spectral window observed by MALDI-TOF MS in clinical microbiology, i.e., 3640–12000m/z, we were able by analyzing the molecular weight of these three ribosomal proteins to classify each strain in one of six subgroups, each of these subgroups corresponding to specific STs and/or CCs. Their detection by MALDI-TOF allows therefore a quick typing of N. meningitidis isolates. •The Andromas database biomarkers used for the microbial identification are identified.•It is possible to differentiate Neisseria meningitidis strains by variations of their ribosomal proteins.•Andromas MALDI-TOF spectra can be compared with bacterial ribosomal sequence types.