Strain-level proteotyping and expression of specific toxins in patients with recurrent Clostridioides difficile infection
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Updated: Nov 1, 2026
A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection
Published on: June 15, 2018
Guillem Seguí1, Beatriz Piñeiro-Iglesias2, Gunnar Jacobsson3
1Department of Infectious Diseases, Institute for Biomedicine, Sahlgrenska Academy of the University of Gothenburg, 41346 Gothenburg, Sweden; Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, 41346, Gothenburg, Sweden; Department of Clinical Microbiology, Sahlgrenska University Hospital, Region Västra, Götaland, 41346 Gothenburg, Sweden; Culture Collection University of Gothenburg (CCUG), Sahlgrenska Academy of the, University of Gothenburg, 41346 Gothenburg, Sweden.
Objectives:
Recurrent Clostridioides difficile infection (CDI) remains a major clinical challenge, and routine diagnostics that detect toxin genes rarely confirm toxin expression or resolve strain relatedness. We assessed whether combining whole-genome sequencing (WGS) with mass spectrometry proteotyping could resolve recurrence mechanisms and confirm toxin production.
Methods:
WGS, protein-level toxin typing and liquid chromatography tandem mass spectrometry (LC-MS/MS) proteotyping were combined. Of 33 isolates, 31 were collected at discrete time points from 14 patients and two lacked patient attribution. Datasets comprised 32 genomes and 29 proteomes (28 matched). Average nucleotide identity (ANI) and core-SNP distances were assessed.
Results:
Most serial isolates in the high-molecular-weight (HMW)-selected cohort shared ANI groups (>99% ANI), including persistence over 353 days, consistent with relapse; one patient showed two ANI groups compatible with reinfection. Six isolates from three patients formed a divergent lineage uniquely carrying cdtA/cdtB, an A3/B5 toxin background, and the only reported acquired resistance-gene hits. LC-MS/MS detected TcdA- and TcdB-derived peptides in all 29 profiled isolates, spanning conserved and subtype-discriminating regions.
Conclusions:
LC-MS/MS proteotyping provides an expression-level layer concordant with genotype and, integrated with WGS, distinguishes relapse from reinfection and links divergent lineages to specific toxin and resistance profiles, complementing genomic and immunoassay-based CDI characterisation.
