Gardnerella biofilm formation in vitro is facilitated by braided sutures: implications for cervical cerclage

Introduction In pregnant individuals with certain indications, sutures may be placed circumferentially around the uterine cervix to prevent dilation. Compared to monofilament sutures, the use of braided suture materials has been linked with the development of a dysbiotic vaginal microbiome, as well as higher rates of infection-associated pregnancy outcomes such as chorioamnionitis and preterm birth. In bacterial vaginosis (BV) anaerobic bacteria, including pathogens, overgrow, forming biofilms in direct proximity to the host epithelium. Gardnerella is highly represented among bacterial vaginosis-like microbiotas. Methods To test our working hypothesis that braided sutures may better support the establishment of high biomass bacterial biofilms compared to monofilament sutures, we measured the extent of Gardnerella bacteria biofilm formation on braided and monofilament sutures in the laboratory. Multiple Gardnerella strains were grown in the presence of braided or monofilament suture materials (polyester or polybutylate-coated polyester versus polypropylene or nylon), and the (biofilm) biomass was measured using crystal violet staining. Results Sutures incubated without Gardnerella were included as controls. To compare staining of biofilm biomass between groups, one-way ANOVA was performed and Šidák was used for pairwise comparisons to control for multiple comparisons between groups. Gardnerella formed significantly more biofilm biomass (>10-fold) on braided polyethylene terephthalate (polyester) sutures compared to monofilament (polypropylene or nylon) sutures (p < 0.0001). This feature was applicable to multiple strains across different taxonomic subsets of Gardnerella. Discussion Together with existing literature, these findings suggest that braided sutures might promote the development of dysbiotic BV-like microbiomes after cerclage placement by facilitating Gardnerella biofilm formation.