A.H.
The number of babies who get sick from GBS is incredibly low. Do research on this bacteria and how rarely it affects babies. A client I worked with several years ago collected a huge volume of data on GBS and in the end, after comparing studies with studies, her conclusion was treating GBS is a big roll of the dice.
I am a home birth midwife and for my clients I offer the option of transferring care to the hospital for IV antibiotics, get them in to a a doctor for a prescription for oral antibiotics to be taken prior to and during labor, a shot of antibiotics that is long-lasting so it will cover the baby for about 40 days, or for moms who want to do something but refuse antibiotics, there is a protocol of natural methods for getting rid of the strep.
In Europe, they have the GBS+ mom do an internal wash with Hibicleanse before birth and they have had great success with this treatment option. Of course, in Europe, they don't treat every single GBS+ mother, either. They only treat when there are two or more risk factors. The only time they treat for a single risk factor is if the woman has a UTI that cultures positive for GBS, because it's believed to be systemic.
I'm throwing this information out there for you so that you know that there's so much more to research on this topic.