The results of the current study show (i) equivalent levels of bladder tissue colonisation in young and aged mice, in contrast to prior findings [24], (ii) equivalent levels of bladder tissue colonisation in young and dam mice, consistent with [24], (iii) increased age, but not parity predisposes to higher bacteriuria burdens during S. agalactiae UTI, and (iv) both age and parity effect the patterns of production of several regulatory and pro-inflammatory cytokines, including KC, MCP-1, IL-17, MIP-1α and RANTES that are expressed during S. agalactiae UTI in mice. This evidence concerns the gene IL17A and bacterial urinary tract infection.