Cyclic-di-AMP confers an invasive phenotype on Escherichia coli through elongation of flagellin filaments.

"Declarations Ethics approval and consent to participateThe study design was reviewed and approved by the Institutional Review Board of Tokai University School of Medicine (No. 20I-35) and was conducted according to principles of the Declaration of Helsinki. Written informed consent was obtained from all participants before their inclusion in the study. Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding This study was supported by a 2021 Tokai University School of Medicine Research Aid grant (210049) (to H.T.), Tokai University Research Organization Grant (21NS331825) (to H.T.), and Tokai University Supporters Association Research and Study Grant (23J00600) (to H.T.). Yakult Bio-Science Foundation (22J026000) (to J.I.), JSIBD Grants-in-Aid for IBD Research (22J029000) (to J.I.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."