(A) Alpha-diversity of bacterial transcripts at the family level from -post, −3dpi, and −7dpi of AuNP-EscC and adjuvant-only vaccinated groups with Chao1 and Shannon index. (B) Relative abundances of bacterial families from -post, −3dpi, and −7dpi of AuNP-EscC and adjuvant-only groups. (C) The relative abundance of the Enterobacteriaceaefamily in each treatment group before and after infection. Significance of p<0.00001 measured between adj-7dpi and all other groups. (D) The relative abundance of the Citrobacter genus in each treatment group before and after infection. Significance of p<0.00001 measured between adj-7dpi and all other groups. (E) The top 25 bacterial genera exhibiting the most significant differences throughout the infection timeline, in AuNP-EscC vaccinated (left) and adjuvant-only treated animals (right). -post, post-immunization fecal sample; −3dpi, fecal samples from 3 days after infection; −7dpi, fecal samples from 7 days after infection.