Susceptibility to rUTI and/or pyelonephritis in humans is associated with polymorphisms in the genes for non-secretor blood group antigens, P1 phenotype, CXCR1, TLR1, TLR2, TLR4, and TLR5 [37], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49]. The gene discussed is CXCR1; the disease is pyelonephritis.