Objective To explore the causal relationship between gut microbiota and urinary tract infections (UTI) using data from genome-wide association studies. Methods The gut microbiota data were sourced from the MiBioGen consortium, comprising genetic variables from 18 340 individuals. UTI data (ieu-b-5.65) were derived from the UK Biobank. Six methods including inverse variance weighted (IVW), Mendelian randomization (MR)-Egger, maximum likelihood, simple mode, weighted mode, and weighted median were employed for two-sample MR analysis on these datasets. Additionally, MR-PRESSO was used to detect and correct for heterogeneity and outliers in the analysis. Cochran’s Q test and leave-one-out analysis were applied to assess potential heterogeneity and multiple effects. Furthermore, reverse MR analysis was conducted to investigate causal relationships between UTI and gut microbiota. Results According to IVW method analysis results, bacterial genera Eggerthella (OR=1.08, 95%CI 1.01 to 1.16, P=0.034) and Ruminococcaceae (UCG005) (OR=1.10, 95%CI 1.01 to 1.20, P=0.022) were found to increase the risk of UTI, while Defluviitaleaceae (UCG011) (OR=0.90, 95%CI 0.82 to 0.99, P=0.022) appeared to decrease it. Reverse MR analysis did not reveal a significant effect of UTI on these three bacterial genera. Our study found no evidence of heterogeneity or pleiotropy based on the results of Cochran’s Q test, MR-Egger, and MR-PRESSO global test. Conclusion In this MR study, we demonstrate a causal association between Eggerthella, Ruminococcaceae, Defluvitalaceae and the risk of urinary tract infections.
