How To Control Urine Infection?

I am 63 yrs of age height is 176 cm weight is 67 KG and I had problem of urine retention in bladder.As suggested by my urologist I have undergone retrograde urethrogram on 26/5/11. I was put on Tab Percin 600(Prulifloxacin) from 25th onwards one tablet perday for seven days.From eight day onwards I have high fever, a blood hematology shows WBC Count 15.67,Neutrophils 81.0%, Lymphocytes 8.5%,basophils 2.0%.All these reading before urethogram was well with in limits.My question is why Percin didnot work to regulate infection and which family of antibiotic should be taken now to control infection.