As someone who has had chronic UTIs for the several years, I understand your frustration. "Modern medicine" can't find the cause of mine either. It has been suggested that I have a connection somewhere between my GI and urinary tract.

If you are spilling sugar (because of your diabetes), that will make getting rid of your bladder infection harder. The sugar will promote the growth of bacteria.

I wonder if you are developing resistant bacteria. I know you don't want to hear this, but the only way to tell is to have your doctor culture and test antibiotic sensitivity.

If your stomach can tolerate it (I can't), many people swear by cranberry juice and there is some evidence that it works. See the following HealthCentral articles:

http://www.healthcentral.com/incontinence/news-258520-31.html

http://www.healthcentral.com/incontinence/news-201272-66.html

There is a drug call Hiprex that can make your urine unfavorable for growth to bacteria. I've used it, but couldn't tolerate the side effects. Links for more info:

http://www.rxlist.com/cgi/generic/hiprex.htm

http://www.webmd.com/drugs/drug-6821-Hiprex+Oral.aspx?drugid=6821&drugname=Hiprex+Oral

Also, you might try changing your diet to make your urine more acidic. (That's one thing cranberry juice does.) Interestingly, certain citrus juices will make your urine more alkalin, which promotes bacterial growth. I have been able to do this with some success.

And, I know you don't want to hear this, but you should see your doctor. If you are not getting what you need from them, find someone else. That's what I have had to do several times.