Introduction

The oral cavity is one of the most diverse microbial habitats in the human body, serving as a critical gateway to both the respiratory and digestive tracts. Among the complex web of microorganisms residing here is Prevotella salivae, a member of the Bacteroidota phylum. While often acting as a commensal part of the oral ecosystem, this microbe's presence and abundance can shift significantly during states of imbalance, known as dysbiosis.

Understanding the role of P. salivae is essential for grasping how the host-microbe interaction influences not only oral health but also potential systemic implications. By utilizing advanced tools like metagenomics and shotgun sequencing, scientists are uncovering how this specific microbe relates to various health outcomes and the maintenance of microbial diversity.

Location of Microbe

Oral Ecosystem

Prevotella salivae is primarily located within the oral cavity, where it colonizes various niches including the saliva and the mucosal surfaces of the mouth.

Behavior During Dysbiosis

Oral Dysbiosis

In the oral ecosystem, P. salivae is associated with shifts in microbial abundance during dysbiosis. It is frequently enriched in specific pathological states, such as proliferative verrucous leukoplakia (PVL), where a general loss of microbial diversity often occurs alongside the proliferation of this species.

Disease Associations

Oral Ecosystem Associations

Within the oral cavity, Prevotella salivae is associated with several distinct conditions. It is notably enriched in patients with proliferative verrucous leukoplakia (PVL), a progressive oral mucosal abnormality. Furthermore, research indicates that an increase in the abundance of P. salivae is associated with an increased risk of developing head and neck squamous cell carcinoma (HNSCC) and has been detected in higher levels in oral squamous cell carcinoma (OSCC) samples compared to fibroepithelial polyps.

Beyond oncology, P. salivae is associated with dental health; it has been found in higher relative abundance in children affected by dental caries compared to those who are caries-free. Interestingly, the microbe also appears in the context of systemic inflammation, as its abundance in saliva is significantly elevated in patients with inflammatory bowel disease (IBD), suggesting a link between oral dysbiosis and intestinal inflammation.

Foods Supporting Healthy Balance

Maintaining a healthy oral ecosystem depends on supporting a diverse microbial community to prevent the overgrowth of opportunistic pathogens. A diet rich in fibrous vegetables, whole grains, and polyphenols (found in berries and green tea) promotes a balanced microbiome by providing prebiotics that support beneficial commensal bacteria.

Reducing the intake of refined sugars and processed carbohydrates is critical, as these substrates can fuel the growth of caries-associated bacteria, including those associated with P. salivae enrichment. Additionally, staying hydrated and incorporating foods that promote saliva production helps maintain the natural buffering capacity of the mouth, supporting the integrity of the gut-oral axis and overall microbial diversity.

Actionable Insights

Managing Oral Microbial Balance

• Prioritize Oral Hygiene: Regular brushing and flossing help prevent the accumulation of biofilms where opportunistic pathogens like P. salivae may proliferate.
• Dietary Modifications: Limit high-sugar foods to reduce the risk of dental caries and associated microbial shifts.
• Regular Screenings: Periodic dental check-ups can identify early signs of mucosal abnormalities, such as leukoplakia, which may be associated with specific microbial signatures.
• Support Systemic Health: Given the association between oral P. salivae and conditions like IBD, maintaining a balanced gut diet may help modulate the overall inflammatory signaling across the host-microbe interaction.

Conclusion

Prevotella salivae is a complex component of the oral ecosystem that exemplifies the delicate balance of the human microbiome. While it exists as a common member of the oral flora, its enrichment is frequently associated with dysbiosis, ranging from dental caries and proliferative verrucous leukoplakia to more severe conditions like head and neck cancers and systemic inflammatory bowel disease. However, it is also observed in contexts that may be beneficial, such as its association with better radiotherapy responses in certain lung cancer patients.

Ultimately, the impact of P. salivae depends heavily on the niche context and the overall microbial diversity of the individual. By focusing on preventive health through diet and hygiene, it is possible to support a stable oral environment that minimizes the risk of dysbiosis and maintains healthy host-microbe interactions.

Peer-Reviewed Sources

• A Comparative Longitudinal Study Analyzing Vaginal Microbiota Differences Between Term and Preterm Pregnancies in Korean Women PMC12028669
• On the Oral Microbiome of Oral Potentially Malignant and Malignant Disorders: Dysbiosis, Loss of Diversity, and Pathogens Enrichment PMC9961214
• Oral Microbiome and Subsequent Risk of Head and Neck Squamous Cell Cancer PMC11428028
• Metatranscriptomics uncovers host immune and microbiome signatures specific to and shared between human metapneumovirus and respiratory syncytial virus infections in children PMC13215961
• Salivary Microbiome Diversity in Caries-Free and Caries-Affected Children PMC5187778
• Association Between the Respiratory Microbiome and Susceptibility to Influenza Virus Infection PMC7442850
• Identification of Oral Microbiome Biomarkers Associated with Lung Cancer Diagnosis and Radiotherapy Response Prediction PMC12735506
• Isolation, identification, and significance of salivary Veillonella spp., Prevotella spp., and Prevotella salivae in patients with inflammatory bowel disease PMC10694262