Vaginal Inoculation of Uropathogenic E. Coli during Estrus Leads to Genital and Renal Colonization
Abstract
Urinary tract infection (UTI) is one of the most prevalent bacterial infections, particularly in women, children, and the elderly. Uropathogenic E. coli (UPEC) is the predominant etiological agent of UTI. To better understand this bacterial infection, the use of the murine model has been predominately applied. In the widely-used murine model of UTI, uropathogens are directly instilled into the urinary bladder, bypassing the lower urogenital tract. We assessed whether vaginal inoculation of UPEC led to UTI and how stages of the estrous cycle would impact bacterial colonization in mice. Mice in proestrus, estrus, metestrus, and diestrus were identified by vaginal cytology and inoculated with UPEC in the vaginal tract. Bacterial loads in the urogenital tract, liver, and spleen were enumerated. Mice in estrus exhibited the highest UPEC burden in all organs except the bladder. Vaginal inoculation resulted in bladder colonization in a UPEC strain-specific manner. In contrast, transurethral inoculation of UPEC led to bladder colonization. Importantly, inoculation by both routes led to vaginal and uterine colonization and concomitant systemic dissemination to the spleen and liver. In summary, vaginal inoculation of UPEC in mice during estrus represents a novel approach to investigating infection of the kidneys and genital tract as well as systemic dissemination from the urogenital tract. Our findings suggest that estrogen primes the urogenital tract to create a conducive milieu for UPEC colonization.
Citation
Robinson, Christen Kimberly (2022). Vaginal Inoculation of Uropathogenic E. Coli during Estrus Leads to Genital and Renal Colonization. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /197806.