Rob, thanks for the info, but Mr. Tux has an upper respiratory infection (URI) not a urinary tract infection (UTI). When one of the other cats had a UTI, I got something called Tinkle Tonic, which is a natural remedy that acidifies the urine. It works pretty well.
Do you know of anything for the respiratory infection? I've tried antibiotics, vitamins, anti-viral homeopathic remedies, and the colloidal silver. Nothing has worked totally....he's still pretty sick.