A recent study found that this specific strain had significant improvement of IBS LAB MEASURES. Since IBS is co-morbid with CFS, it should also cause improvement of CFS.
There is an updated summary in 2018, recommended reading.
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.
A reader has reported a histamine reaction to this probiotic.
This is in agreement with published studies
““. He had taken the probiotic Infloran Berna (Berna Biotech) which contained Lactobacillus acidophilus and Bifidobacterium infantis before he started to experience recurrent episodes of D-lactic acidosis”