The thing with Strep b is you could test +ive for it now & then be -ive at the birth or vise versa. Something like 95% of the (female) population will test +ive for it at some point or another. I remember being told that it had alot to do with ones diet. As in your diet creating the right environment down there for it to live in. I just see it as one of those stock standard things that we are made to worry needlessly over, as usual!