SPeDE

SPeDE performs dereplication of microbial isolates from matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry spectra to identify nonredundant spectra representing unique operational isolation units for high-throughput microbial diversity analyses.

Key Features:

• Implementation: Python-based implementation for spectral processing and dereplication.
• Dereplication strategy: Combines global similarity and local peak comparisons of MALDI-TOF MS spectra to identify unique spectral features and determine nonredundant spectra.
• High taxonomic resolution: Distinguishes species- and strain-level differences in bacterial MALDI-TOF MS spectra.
• Performance evaluation: Validated on datasets comprising thousands of spectra from diverse bacterial strains across multiple phyla, identifying redundant spectra while retrieving representative reference spectra for strains.
• Outputs: Produces nonredundant reference spectra and assignments of operational isolation units (OIUs).

Scientific Applications:

• Culture-dependent clinical and environmental studies: Enables rapid dereplication of isolates characterized by MALDI-TOF MS to accelerate diversity surveys.
• Culturomics: Supports high-throughput selection of nonredundant isolates in culturomics workflows, addressing limitations associated with long-term storage and traditional gene marker-based sequencing approaches.
• Representative selection for downstream analyses: Identifies representative isolates for downstream marker-gene or genomic characterization.

Methodology:

Performs spectral processing and dereplication of MALDI-TOF MS data by comparing spectra using both global similarity measures and local peak comparisons to detect unique spectral features and assign nonredundant spectra; implemented in Python.