The Utility of Bacterial Volatile Organic Compounds to Differentiate Bacteriomes

Objectives: Recent studies indicate a strong correlation between the salivary microbiome and the VOCs emanating from saliva. In this investigation, we explored the possibility of using VOCs to detect bacterial communities in salivary samples. In future such technology may have the potential to differentiate healthy individuals and those with systemic disease. Therefore, we aimed to assess the possibility of different bacterial niches separation based on oral bacteriome produced VOCs in culture media.
Methods: Pooled oral sample was prepared by collecting oral rinse samples from three healthy individuals. Appropriate dilution of the pooled oral sample was cultured on agar plates both aerobically and anaerobically. The resultant bacterial colonies were harvested and pooled in phosphate buffered saline to provide samples for VOCs analysis. Uninoculated broth culture media were used as negative controls. The samples were suspended in solid-phase microextraction vials (containing broth media) further incubated aerobically and anaerobically for overnight and subjected to head-space VOCs extraction and gas-chromatography/mass-spectrometry.
Results: The multigroup analysis (ANOVA) of detected VOCs from inoculated and uninoculated bacterial culture media indicated 1619 significantly different ion-peaks out of 4878 aligned peaks (p≤0.01) that could be clustered into six principal components that explained 23% and 13% variations. The pairwise analysis (Welch’s t-test) showed well separation of aerobically and anaerobically inoculated media with the same pooled-oral sample by detection of 247 significant up- and down-regulated ion-peaks (p≤0.01, fold-change intensity>1.5). The pairwise comparison between inoculated media with oral pooled sample and those inoculated with pooled colonies indicated 163 and 46 significantly up- and down-regulated ion-peaks in aerobically and anaerobically incubated media, respectively.
Conclusions: This pilot study indicates the possibility of using bacterial VOCs to differentiate various but closely related bacteriomes from the oral niche. In translational terms, the use of bacterial VOCs in future may help differentiate healthy and diseased individuals with distinct oral bacteriomes.