Screens a negative-mode LC-MS peak table for the m/z markers of 59 bacterial taxa found in cultured isolates (Chen et al., Nat Commun 2025). A matched marker shows that a feature of that m/z is present, not that the organism is: every match count is compared with decoy libraries, and a taxon needs confirmation by sequencing or MS2.

Peak table: features named by m/z, e.g. 284.1616, or by m/z and retention time, e.g. 284.1616__1.12 (284.1616_1.12, 284.1616@1.12 and 284.1616/1.12 are also read); samples in columns with a Label row, or in rows with a Label column; at least two groups of three samples. Raw or normalized intensities, not log-transformed; empty cells count as not detected. QC and BLANK samples are left out of the scores. Up to 50 MB.
Ion mode: negative. The markers are [M-H]- and [M+Cl]- ions; positive-mode data match only by chance.
Marker library: 359 m/z markers (291 primary markers and 68 isotope peaks, m/z 213-1000) of 59 taxa at six ranks (34 species, 7 genera, 9 families, 3 orders, 4 classes, 2 phyla), found by rapid evaporative ionization MS (REIMS) of 3,274 cultured isolates of 246 species; Chen W. et al., Nat Commun 16:165 (2025), Supplementary Data 1-3, CC BY 4.0.