Our data demonstrate that following infection, early and persistent bacterial colonization, renal inflammation, and tubulointerstitial fibrosis are dependent on C5aR1, suggesting that C5aR1 facilities the pathogenesis of chronic kidney infection by enhancement of bacterial colonization of tubular epithelium, promotion of local inflammatory responses, and impairment of phagocytic function of MO/MΦs. Here, C5AR1 is linked to infection.