I am 32 weeks pregnant with 3rd and during my 2nd pregnancy I had?

Group B Streps . Since the start of this pregnancy I have told my concerns to the midwifes that I may still have it, but they have brushed me off saying they dont Screen for it and only do regular urine tests. I did a bit of research on web tonight and one site said that once you had Group B Streps it is impossible to eradicate it, and that it was difficult to detect as it comes and goes from your body. I have the midwife tomorrow and I guess my question is "Can I have antibiotics regardless for this delivery, just incase?" What would you do? OR what have been your experiences on Steps B?