Respected user, hi I evaluated your query thoroughly. * Recurrent UTI have vivid reasons as - resistance to particular antibiotic - different causative organisms - load of infection - improper previous treatments - inadequate hydrations with altered urinary pH - associated conditions as Diabetes or others - sexually transmitted disease - immunocompromised states - improper hygiene * Clearing infection in how many days depend upon the bacterial susceptibility to the antibiotic , host response , load of infection , level of hydrations etc. may be cleared in 3 days if minor but may take more if moderate to severe infection. * After any No. of doses of Levofloxacin it remains in blood stream for 6-8 hours only ( not for 3-5 days ) Hope this clears your doubts Thanks for using Health care magic & keeping trust in our medical services. Wishing you healthy life ahead. Welcome for any further assistance. Regards dear take care.