GBS Prophylaxis question

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anonperson

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Quick clinical scenario:

28 year old at 30 weeks comes in with preterm labor. GBS cultures are obtained and eventually come back positive. Patient is eventually discharged. No history of GBS bacteruria and no prior infants with invasive GBS disease.

Two questions:

1. Should we be obtaining GBS cultures on this patient at 35-37 weeks? Or is this patient being managed as GBS positive now on?

2. If GBS cultures were repeated at 35-37 weeks and they subsequently are negative. Are we managing the patient based on this negative value now?

3. If the patient returns in active labor at 39+ weeks and has not had any additional GBS testing since the testing done at 30 weeks, treat or not treat?

This scenario is in reference to the ACOG ID supplement on the website.

My thought was the test will have an inherent false negative rate and that one couldn't rely on that to assume transient colonization in light of a previous positive culture during the pregnancy.

I am looking for the "test" answer to this (CREOGS and boards etc)
 
A great question. Per the 2010 CDC guidelines: "Women with threatened preterm delivery who have a GBS screen performed that is positive and do not deliver at that time should receive GBS prophylaxis when true labor begins (AII)."

Therefore, to answer your questions:
1. Repeat if the one at 30 weeks was negative. In this case, given that it was positive, I would just move to treat.
2. I would not. If you had a positive test during the first or second trimester (and no GBS bacteruria), then I might consider a repeat test, but for me (at least personally and unencumbered by evidence), 30 weeks is rather late in the pregnancy and I would have hesitancy trusting a negative culture.
3. Treat.

Here is the link to the 2010 guidelines. It's a pretty good idea to review them as I saw questions related to this on my general and MFM boards.
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5910a1.htm?s_cid=rr5910a1_w

Best of luck!
 
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