BACKGROUND Yersinia enterocolitica is the main etiological agent of yersiniosis and includes 6 biotypes (1A/B, 2-5). Biotype 1A (BT1A) is generally regarded as non-pathogenic despite evidence of pathogenic potential and ystB and ymoA virulence gene carriage, which encode an enterotoxin and modulator, respectively. We aimed to assess the association between BT1A and gastrointestinal symptoms. METHODS Laboratories provided Y. enterocolitica cultures to the National Reference Centre for characterization. We collected epidemiological data from positive BT1A cultures (n=183) by questionnaires to clinicians. We included questions on symptoms; etiology of gastrointestinal symptoms; hospitalization and immunosuppression status. Whole-genome sequencing (Illumina) was performed on 57/183 strains. The genotyping was performed by core-genome multilocus sequence typing (cgMLST) (Galaxy) and screening for virulence genes (BIGSdb). Association between reported etiology of gastrointestinal symptoms and genotype was assessed calculating the virulence genes-specific odds ratio (OR) and 95% confidence intervals (95%CI).     RESULTS Among patients, 99/183 were female (53.80%); 60 (32.79%) were ≥65 years old and 16 (8.75%) were ≤4 years old. Overall, in 103 (56.28%) BT1A was reported as the etiological agent of gastrointestinal symptoms; 24 (13.11%) required hospitalization and 18 (9.84%) were immunosuppressed. In total, 5⅗7 strains (92.98%) contained ystB and ymoA. However, these were not significantly associated with being reported etiological agent of gastrointestinal symptoms (OR:4.81, 95%CI:0.35-267.11, p=0.19). It was not possible to determine the association with a certain cgMLST genotype or virulence gene involved. CONCLUSIONS We demonstrate the potential ability of BT1A strains to cause gastrointestinal symptoms, including in immunocompetent patients. Our genotyping results might be explained by the small number of strains studied. To elucidate the burden of gastrointestinal disease it is crucial to implement a system for routine identification and characterization of BT1A.