A reader starting taking this and their two earlier uBiomes had zero lactobacillus and zero bifidobacterium. Both of these bacteria genus appear at low level afterwards (an improvement of both microbiome and general state).
“Pyrroloquinoline quinone (PQQ), an aromatic tricyclic o-quinone, was identified initially as a redox cofactor for bacterial dehydrogenases. Although PQQ is not biosynthesized in mammals, trace amounts of PQQ have been found in human and rat tissues because of its wide distribution in dietary sources. Importantly, nutritional studies in rodents have revealed that PQQ deficiency exhibits diverse systemic responses, including growth impairment, immune dysfunction, and abnormal reproductive performance. Although PQQ is not currently classified as a vitamin, PQQ has been implicated as an important nutrient in mammals. In recent years, PQQ has been receiving much attention owing to its physiological importance and pharmacological effects.” 
” PQQ supplementation resulted in significant decreases in the levels of plasma C-reactive protein, IL-6 and urinary methylated amines such as trimethylamine N-oxide, and changes in urinary metabolites consistent with enhanced mitochondria-related functions. ” 
- Pyrroloquinoline Quinone, a Redox-active o-Quinone, Stimulates Mitochondrial Biogenesis by Activating SIRT1/PGC-1α Signaling Pathway. 
The Effect of Pyrroloquinoline Quinone on Apoptosis and Autophagy in Traumatic Brain Injury.
- “. Electroencephalogram indicated that pyrroloquinoline quinone improved brain electrophysiological function after traumatic brain injury. The results of CCK-8 test showed that pyrroloquinoline quinone could increase the viability of primary astrocyte treated with Glutamate. Lactate dehydrogenase (LDH) assay demonstrated that pyrroloquinoline quinone decreased LDH content in primary astrocyte exposed to Glutamate.”
- Modulation of glycine sites enhances social memory in rats using PQQ combined with d-serine.
- Neuroprotective effects of pyrroloquinoline quinone against rotenone injury in primary cultured midbrain neurons and in a rat model of Parkinson’s disease.
Effect of the Antioxidant Supplement Pyrroloquinoline Quinone Disodium Salt (BioPQQ™) on Cognitive Functions .
- “Subjects were orally given 20 mg of BioPQQ™ per day or placebo, for 12 weeks. “
- “The preliminary experiment using near-infrared spectrometry (NIRS) suggests that cerebral blood flow in the prefrontal cortex was increased by the administration of PQQ. The results suggest that PQQ can prevent reduction of brain function in aged persons, especially in attention and working memory.”
- Pyrroloquinoline Quinone Decelerates Rheumatoid Arthritis Progression by Inhibiting Inflammatory Responses and Joint Destruction via Modulating NF-κB and MAPK Pathways. 
Effects of Pyrroloquinoline Quinone Disodium Salt Intake on the Serum Cholesterol Levels of Healthy Japanese Adults. 
- ” Our study findings suggest that PQQ suppressed the LDL-chol level, which is an important finding, because a high level of this lipid is a risk factor for various lifestyle-related disease”
- “When provided PQQ, E. coli utilizes it as an enzymatic cofactor in enzymes important to glucose and alcohol metabolism. Although it seems likely that PQQ supplements may alter metabolic features of E. coli, whether PQQ influences lactobacillus and other organisms that are utilized as probiotics remains to be examined. Making the link between PQQ and probiotic use nevertheless has potential in describing certain effects of PQQ.” [src]
One discussion group:
- THUMBS UP: “DID yield decent enough beneficial therapeutic effects; and DID NOT EXPERIENCE intolerable side effects; and IS WORTH the cost” (71 votes [61.74%] – View)
- THUMBS DOWN: “DID NOT yield decent enough beneficial therapeutic effects; and/or EXPERIENCED intolerable side effects; and/or IS NOT WORTH the cost” (44 votes [38.26%] – View)
- “I have FMS/CFS and started taking PQQ recently and it has made a huge difference in my mental health as well as fatigue. Nothing has ever made any difference to the crippling fatigue I experience day in day out, so I was so happy to have come across this. I also started taking ubiquinol (Coq10 did nothing for fatigue) which also has the same effect as the PQQ (or maybe it is boosting what the PQQ has regenerated?) but sometimes when I take them together I become really angry and can end up in an uncontrollable rage. B12 also does this to me so maybe it is a methylation issue.” [Src]
The documented neuroprotective aspects of PQQ makes it an attractive supplement for CFS. There is an absence of studies on the microbiome or studies with CFS/IBS/FM.
There is no supporting evidence that it increases Lactobacillus or Bifidobacterium, nor evidence of adverse effect.