I just wanted to share a recent experience. I tested positive for group B Strep and was advised by a doula who was advised by Michel Odent to try garlic inside the vagina for 3-5 days. You use a peeled cut clove and thread it with cotton so you can get it out again (I was a bit silly on this the first time and didn't bother - cue amusing moments with husband trying to retrieve it - don't recommend this)
I did it for 4 days and a repeat test has just come back negative!
Must be worth a try (assuming your waters haven't gone to be on the safe side) - if you can cope with the aesthetic issues!