Mac24 - I cannot imagine that the SLD would have anything to do with the SLD. UTI's are extremely common among women (especially those that are sexually active). Some women, for some reason, tend not to feel the typical burning and frequency that most women feel with UTI's. The first sign of symptoms that these women get are when the infection reaches the kidneys at which point they feel back pain, nausea, headache and flu-like symptoms.
Here are the tips I give my patients to avoid UTI's -
1) Hydration - forward flow prevents the urine from sitting around brewing stuff
2) Good Hygeine - Wiping front to back, avoiding overly tight clothes, avoid douching, etc..
3) Sex - Try to urinate as soon as convenient after intercourse to clear any bacteria that may have migrated up your urethra
4) Be alert to signs / symptoms - If you don't get the burning / frequency - look for a funny smell, cloudy color, back pain in the middle of your back (especially if only on one side), fevers, nausea / vomiting without diarrhea, flu like symptoms without sneezing, coughing or sore throat.
5) Finally, if you keep getting infections despite following all of the above consider acidifying your urine using either Vitamin C or Cranberry (either juice or pill-supplements) - these can be used either on a daily basis or only on days when you are going to have intercourse (if your symptoms seem related to that).