Uropathogenic Escherichia coli infection of the male urogenital tract in wild type and TLR4-KO mice

OLIVERA, CAROLINA; GODOY, GLORIA J.; SALAZAR, FLORENCIA C.; SANCHEZ, LEONARDO R.; MOTRICH, RUBEN D.; RIVERO, VIRGINIA E.

Mar del Plata

Congreso; LXIV Reunión Anual de SAI, LXI Reunión Anual de la SAIC, XLVIII Reunión Anual de la SAFE, VII Reunión Anual de la NANOMEDAR, V Congreso Nacional de la AACyTAL.; 2016

Urinary tract infections are among the most common infections in men being Escherichia coli the most frequently isolated pathogen. Urine reflux into the intra-prostatic ducts is a frequent route of access for the uropathogenic bacteria that causes lower and upper male urogenital infections. In the present study, we analyzed the development of pain, bacterial spread and inflammation after transurethral instillation of saline solution or a suspension containing 1x 108 CFU of E. coli 1677 into adult C57BL/6 (wild type) and TLR4-KO mice. Pelvic pain was assayed as tactile allodynia using Von Frey filaments at baseline and at different time points after infection. At day 7, animals were euthanized, urethral and prostatic tissues were excised, and the presence of bacteria and leukocyte infiltration was analyzed by microbiological culture and immune staining followed by flow cytometry. Acute pelvic pain was evidenced by similarly increased allodynia responses in both, E coli-infected C57BL/6 and TLR4-KO mice when compared with control mice. Besides, bacterial inoculation resulted in an ascending infection of the male urogenital tract in both, C57BL/6 and TLR4-KO mice. Bacterial burden in urethra was similar between both mice strains. However, higher loads were detected in prostate tissue from infected TLR4-KO mice when compared to infected C57BL/6 mice (p<0.05). The analysis of tissue leukocyte infiltration revealed the presence of increased amounts of CD45+ cells in urethra and prostate from both mice strains being GR1+, F480+ and CD11b+ cells the most abundant populations detected, with only small proportions of CD3+ and CD19+ cells.Our results show that transurethral inoculation of uropathogenic E. coli 1677 causes and infection of the lower and upper male urogenital tract showing an ascendant pattern that is accompanied by local inflammation and pelvic pain development. In addition, our results suggest that immune effector mechanisms triggered by TLR4 are important for an efficient bacterial clearance.