Introduction

The human microbiome is a complex network of microorganisms that play critical roles in maintaining systemic health. Among these, the phylum Synergistetes represents a specialized group of bacteria found in diverse niches, including the oral cavity and the gastrointestinal tract. Understanding the functional potential of these bacteria is essential for identifying markers of health and dysbiosis.

Location of Microbe

Oral Ecosystem

In the oral cavity, Synergistetes are primarily located within the subgingival and supragingival biofilms, as well as the saliva and tonsillar crypts.

Gut Ecosystem

Within the gastrointestinal tract, Synergistetes are found as part of the fecal microbial community, contributing to the overall diversity of the gut ecosystem.

Behavior During Dysbiosis

Oral Ecosystem: In states of oral dysbiosis, such as periodontitis or Molar-Incisor Pattern Periodontitis, Synergistetes often show increased abundance within the oral biofilms, shifting from a homeostatic relationship to one associated with inflammation.

Gut Ecosystem: In the gut, the behavior of Synergistetes varies; they are associated with increased abundance in specific conditions like heart failure with sarcopenia, but decreased abundance in others, such as autoimmune hepatitis or IgA nephropathy.

Disease Associations

Oral Ecosystem Associations

Within the oral niche, Synergistetes are strongly associated with inflammatory conditions. Specifically, they are linked to periodontitis and Molar-Incisor Pattern Periodontitis, where their enrichment coincides with a hyperinflammatory response and the downregulation of epithelial barrier defense genes. Furthermore, an increased abundance of this phylum is observed in cases of peri-implantitis, where they are part of a pathogen-enriched microbiome associated with marginal bone loss during healing. Interestingly, in the context of tonsillar squamous cell carcinoma, a higher abundance of Synergistetes is actually found in control cohorts compared to tumor patients.

Gut Ecosystem Associations

In the gut ecosystem, Synergistetes are associated with a variety of systemic and autoimmune conditions. They show a significant increase in abundance in older patients with heart failure and sarcopenia, suggesting their potential as a biomarker for muscle loss in cardiac patients. Conversely, a decrease in Synergistetes abundance is associated with autoimmune hepatitis and primary IgA nephropathy, indicating that their loss may be a feature of certain autoimmune-driven dysbiosis. Additionally, shifts in the distribution of this phylum have been observed in patients with colorectal cancer, highlighting its relevance in gastrointestinal health.

Foods Supporting Healthy Balance

Maintaining a balanced microbiome across both oral and gut ecosystems requires a dietary approach that supports overall microbial diversity. While specific foods for Synergistetes are limited, general dietary patterns significantly influence their abundance. For example, higher coffee intake has been associated with a greater abundance of Synergistetes in the oral microbiome. In the gut, a diet rich in fiber and a high Healthy Eating Index (HEI) score are generally associated with better glycemic control and a more stable microbial community, reducing the risk of systemic inflammation. Integrating a variety of plant-based foods can help maintain the gut barrier integrity and prevent the opportunistic overgrowth of bacteria associated with inflammatory signaling.

Actionable Insights

General Microbiome Health

• Focus on a diverse, fiber-rich diet to maintain gut barrier integrity and support a wide array of commensal bacteria.
• Prioritize adherence to dietary guidelines (High HEI score) to reduce chronic systemic inflammation.

Oral Health Management

• Maintain rigorous oral hygiene and regular dental check-ups to prevent the shift toward a periodontitis-associated microbiome.
• Monitor gingival health for signs of inflammation, as the enrichment of Synergistetes is associated with periodontal disease progression.

Gut Health Monitoring

• Be aware that changes in gut microbial abundance, including Synergistetes, can be associated with systemic conditions like heart failure and sarcopenia in older adults.

Conclusion

The biological impact of Synergistetes is highly dependent on the specific strain and the ecological niche it occupies. In the oral ecosystem, its enrichment is typically associated with inflammatory periodontal conditions and bone loss. In the gut ecosystem, its role is more nuanced, acting as a potential biomarker for sarcopenia in heart failure patients while being decreased in certain autoimmune liver and kidney diseases. This highlights the importance of considering the specific ecosystem context when interpreting metagenomic data to ensure a balanced and healthy host-microbe interaction.

Peer-Reviewed Sources

• Periodontal inflammation: Integrating genes and dysbiosis - PMC6924568
• Characteristics of the fecal microbiome and metabolome in older patients with heart failure and sarcopenia - PMC9998919
• Fecal Microbiomes Distinguish Patients With Autoimmune Hepatitis From Healthy Individuals - PMC7416601
• Fecal microbiota characteristics of Chinese patients with primary IgA nephropathy - PMC7071635
• Exploring the microbiome of healthy and diseased peri-implant sites using Illumina Sequencing - PMC7209775