What are the treatments possible E-coli infection in urinary tract and kidney?

My brother is suffering from Urinary tract infection since Nov. last year. Inspite of lot of antibiotic treatment given almost throughout the last six months, it is recurring. This infection is interfering with the treatment of his stage 4 B-cell nonhodgkin lymphoma also with Rituximab by causing reducting in Haemoglobin and BP. Is there any alternative treatment for UTI and lymphoma.