The Role of the Microbiome in Mood
David Perlmutter in The Microbiome and the Brain, 2019
Evaluating gut microbial composition and metabolic function in depressed versus non-depressed individuals has been one popular method for investigating the relevance of the BGMA to depression. Several studies have looked for evidence of altered microbial diversity in depressed individuals, but most have shown no difference compared to controls; surprisingly, one study even showed increased diversity, a finding most often considered as a sign of health (Naseribafrouei, Hestad et al. 2014; Jiang, Ling et al. 2015; Zheng, Zeng et al. 2016; Chen, Zheng et al. 2018). Evaluation of the specific taxa of bacteria in depression has also been inconsistent. As Bifidobacteria and Lactobacillus are often considered the “good bacteria” and are most often included in probiotic interventions, many studies have evaluated their abundance in depression. One study showed lower abundance of Lactobacillus in depression. (Aizawa, Tsuji et al. 2016), and two studies showed increased levels of bacteria from the genus Alistipes in depression with one of them also showing correlation of depressive symptoms with this finding. Alistipes has previously been shown in preclinical studies to increase with stress and to be associated with inflammation, while in humans it has been associated with irritable bowel syndrome (IBS) (Naseribafrouei, Hestad et al. 2014).
Bacteroides
Dongyou Liu in Laboratory Models for Foodborne Infections, 2017
The genus Bacteroides has undergone major taxonomic revisions in the past few years, and most species suffer changes frequently. Suitable taxonomic changes have become important to clinicians and microbiologists, since these changes can be used as an indicator of virulence or antimicrobial resistance. It is known that some species of the Bacteroides genus, such as B. thetaiotaomicron, are much more resistant to antimicrobials than B. fragilis, for example. In 1990, various species were moved to other genera, including Porphyromonas and Prevotella, and others were included, such as Dialister, Megamonas, Mitsuokella, Tannerella, Tissierella, and Alistipes. By using culture-independent techniques such as 16S rRNA gene sequencing, a number of new species have been added to the genus Bacteroides, achieving more than 20 bacterial species.2,3 In 2005, new species added to this genus included Bacteroides goldsteinii, Bacteroides nordii, and Bacteroides salyersai, Bacteroides plebeius and Bacteroides coprocola (isolated from human feces), and Bacteroides massiliensis (isolated from the blood of a newborn). Subsequently, B. goldsteinii, Bacteroides distasonis, and Bacteroides merdae were moved to the genus Parabacteroides.4 The occurrence of species of the B. fragilis group in the fecal microbiota of children with diarrhea is shown in Table 16.2.
The intestinal microbiota and metabolites in patients with anorexia nervosa
Published in Gut Microbes, 2021
Petra Prochazkova, Radka Roubalova, Jiri Dvorak, Jakub Kreisinger, Martin Hill, Helena Tlaskalova-Hogenova, Petra Tomasova, Helena Pelantova, Martina Cermakova, Marek Kuzma, Josef Bulant, Martin Bilej, Kvido Smitka, Alena Lambertova, Petra Holanova, Hana Papezova
Patient renourishment led to minor bacterial composition changes (Table 6), which are supported by the positive correlation of hospitalization length and bacteriome divergence of AN1 vs. AN2. The bacteriome of patients after weight gain was still more similar to the bacteriome of patients at admission than to the bacterial composition of healthy controls, which is in accordance with Mack et al.13 We detected a significant change in a subset of OTUs that did not correspond to the results from a separate genus-level analysis; however, these OTUs may play an important role in AN pathophysiology. For example, only a single Alistipes OTU (out of 14 detected) exhibited a significant abundance increase in AN1. This OTU_3215 is related to A. finegoldi and A. onderdonkii (Fig. S3). Different strains of the Alistipes genus were shown to have unique physiological roles associated with different diseases and disorders.25 Since Alistipes can hydrolyze tryptophan (serotonin precursor) to indole and thus decreases serotonin availability, Alistipes increased abundance can disrupt the gut-brain axis. Further, a decrease in serotonin is associated with depression.26
Classification of Parabacteroides distasonis and other Bacteroidetes using O- antigen virulence gene: RfbA-Typing and hypothesis for pathogenic vs. probiotic strain differentiation
Published in Gut Microbes, 2022
Nicholas C. Bank, Vaidhvi Singh, Alex Rodriguez-Palacios
Parabacteroides distasonis rfbA gene sequences previously collected from NCBI were compiled in CLC Viewer 8.0 (commercially available) and used to construct two alignments and phylogenetic trees: one alignment and tree for the Pdis rfbA nucleotide sequences and the second for the translated amino acid sequences. Additionally, a third alignment and tree including rfbA gene sequences from Pdis, other Parabacteroides spp., Bacteroides spp., Alistipes spp., Prevotella spp., Escherichia spp., Klebsiella spp., Salmonella spp., and Shigella spp., were constructed to provide evolutionary context and for observation of clustering patterns. Results were used to determine phylogenetic relatedness and rfbA gene variance within Pdis strains as well as between Pdis and other bacterial species. A separate phylogenetic analysis of lpxK gene nucleotide and amino acid sequences was performed, the results of which were used to determine the comparative discriminatory ability of the rfbA gene to aid in strain characterization.
Prenatal androgen exposure causes hypertension and gut microbiota dysbiosis
Published in Gut Microbes, 2018
Shermel B. Sherman, Nadeen Sarsour, Marziyeh Salehi, Allen Schroering, Blair Mell, Bina Joe, Jennifer W. Hill
The microbiome exhibits alterations in PCOS patients and in animal models of excess androgens. Recent studies have found that the profiles of bacterial abundance exhibit similarities between the orders Clostridales and Bacteroidales.22,31,32 Obese and non-obese women with PCOS had enriched Bacteroidetes and a decreased abundance of Akkermansia (of the phylum Verrucomicrobia), Alistipes, Corprococcus, and Ruminococcus.33Akkermansia prevalence decreased in diet-induced obesity rats and was inversely correlated with peripheral inflammation in adipose tissue.34Alistipes, a bile acid-tolerant bacteria from the genus Bacteroidetes, was decreased in letrozole-treated PCOS mice. In addition, abundance of Alistipes positively correlated with fecal levels of short-chain fatty acids (SCFAs)35−37, which are thought to reduce obesity and insulin resistance.38,39 Finally, a decrease in bacteria of the genus Coprococcus and Ruminococcus were both associated with activation of the hypothalamus-pituitary-adrenal axis and stress-induced depression.40,41
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