A recent study found that this specific strain had significant improvement of IBS. Since IBS is co-morbid with CFS, it should also cause improvement of CFS. There are 10 studies on this and IBS on PubMed
- Fecal excretion of Bifidobacterium infantis 35624 and changes in fecal microbiota after eight weeks of oral supplementation with encapsulated probiotic. (2013)
- Effect of probiotic species on irritable bowel syndrome symptoms: A bring up to date meta-analysis.
- Bifidobacterium infantis 35624: a novel probiotic for the treatment of irritable bowel syndrome.
- Efficacy of an encapsulated probiotic Bifidobacterium infantis 35624 in women with irritable bowel syndrome.
- Probiotic Fermented Milk Containing Dietary Fiber Has Additive Effects in IBS with Constipation Compared to Plain Probiotic Fermented Milk.
- Lactobacillus and bifidobacterium in irritable bowel syndrome: symptom responses and relationship to cytokine profiles.
“There was not a clear positive effect of probiotics concerning the quality of life.Conclusions: some probiotics are an effective therapeutic option for IBS patients, and the effects on each IBS symptom are likely species-specific.” 
There is a single study looking at CFS, Bifidobacterium infantis 35624 modulates host inflammatory processes beyond the gut which observed ” both gastrointestinal (UC) and non-gastrointestinal (CFS and psoriasis) patients had significantly increased plasma levels of C-reactive protein (CRP) and the pro-inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) compared with healthy volunteers. B. infantis 35624 feeding resulted in reduced plasma CRP levels in all three inflammatory disorders compared with placebo. “, the full research paper is available [here].
So where do you get this species? Align Digestive Care Probiotic Supplement appears to be a single species probiotic consisting only of this species (which I am very happy about it not being a mix). For more information see http://www.aligngi.com/
See Comments: for items Bifidobacterium Infantis – Align If you got a FRESH BOX … the study dosage is 10 capsules per day (10 BCFU) if you want to repro a successful study
that is $7.50/day. While the strain is unknown, Epigenetics product may be a lot cheaper (at 5 bn CFU/serving) or $0.95/day.