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Comment by ValentineC | Hacker News Reader

It's scary that Bacteroides fragilis is being seen as some kind of "autism cure" [1], and some people actively seek out probiotics with it.

[1] https://www.nature.com/news/bacterium-can-reverse-autism-lik...

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Bacteroides fragilis is part of normal gut flora[1]. It can cause infections in the bloodstream(like after surgery/from disease) but trying to balance it in the gut is a different issue entirely. The 2013 study did show some reduction in autism-like symptoms in mice. And they did another mice study on probiotic Lactobacillus reuteri in 2016 with reduction of autism-like symptoms as well.

It's not a cure, but they are studying it to help symptoms. I'm fairly certain you can't buy B. Fragilis commercially anyways.

https://www.autismspeaks.org/blog/2016/06/24/new-findings-pr...

[1] https://en.wikipedia.org/wiki/Gut_flora

Do probiotics generally work against the bacteria mentioned in the article?

If the cancer risk is low enough and the treatment works it might be worth it. CT scans cause cancer too and yet people get them all the time.

Huh. The wikipedia page of bacteriodes fragilis says that it's an obligate anaerobe[1]. I thought that our bodies were filled circulating oxygen-rich fluids. How can obligate anaerobes surivive in our bodies?

[1] https://en.wikipedia.org/wiki/Bacteroides_fragilis

Your colon hopefully isn't filled with oxygen-rich fluids. And I'm pretty sure that most of the oxygen in blood is bound in red blood cells, so the bacteria would be pretty unlikely to be harmed by it.

https://www.ncbi.nlm.nih.gov/pubmed/3568965

Gangrene can be treated in part by using a hyperbaric chamber to increase oxygen content of the body. Presumably, if our tissues were all oxygenated, gangrene would never happen.

Your body is not a sack. There are different structures, with different oxygenation levels in them. Anaerobic bacteria do especially well in mucous-rich areas - the mouth, the gut, and the female genital tract.

Yes but, having B fragilis doesn't mean you'll get cancer. So it's like any medical treatment, you weigh the risks against the benefits.

Yikes. Is this a common additive to probiotics?

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