Supragingival Plaque Microbial Community Analysis of Children with Halitosis

As one of the most complex human-associated microbial habitats, the oral cavity harbors hundreds of bacteria. Halitosis is a prevalent oral condition that is typically caused by bacteria. The aim of this study was to analyze the microbial communities and predict functional profiles in supragingival plaque from healthy individuals and those with halitosis. Ten preschool children were enrolled in this study; five with halitosis and five without. Supragingival plaque was isolated from each participant and 16S rRNA gene pyrosequencing was used to identify the microbes present. Samples were primarily composed of Actinobacteria, Bacteroidetes, Proteobacteria, Firmicutes, Fusobacteria, and Candidate phylum TM7. The alpha and beta diversity indices did not differ between healthy and halitosis subjects. Fifteen operational taxonomic units (OTUs) were identified with significantly different relative abundances between healthy and halitosis plaques, and included the phylotypes of Prevotella sp., Leptotrichia sp., Actinomyces sp., Porphyromonas sp., Selenomonas sp., Selenomonas noxia, and Capnocytophaga ochracea. We suggest that these OTUs are candidate halitosis-associated pathogens. Functional profiles were predicted using PICRUSt, and nine level-3 KEGG Orthology groups were significantly different. Hub modules of co-occurrence networks implied that microbes in halitosis dental plaque were more highly conserved than microbes of healthy individuals' plaque. Collectively, our data provide a background for the oral microbiota associated with halitosis from supragingival plaque, and help explain the etiology of halitosis.