Group B Streptococcus (GBS) Urinary Tract Infection Involves Binding of GBS to Bladder Uroepithelium and Potent but GBS-Specific Induction

Group B Streptococcus (GBS) causes urinary tract infections, but the pathogenic mechanisms underlying GBS urinary tract infections are unknown. We investigated whether uro-pathogenic GBS can bind to bladder uroepithelium to initiate urinary tract infection. Uropathogenic GBS isolated from a patient with acute cystitis bound to human T24 bladder uro-epithelial cells in close association with F-actin in statistically significantly higher numbers compared with nonuropatho-genic GBS. In vivo modeling using transurethrally infected mice revealed superior fitness of uropathogenic GBS for blad-der colonization and potent uropathogenic GBS–specific up-regulation of interleukin 1a during infection. Thus, binding of uropathogenic GBS to uroepithelium and vigorous in-duction of interleukin 1a represents the initial stages of GBS urinary tract infection