title: Metagenomic detection of phage-encoded platelet-binding factors in the human oral cavity.
abstract: The human oropharynx is a reservoir for many potential pathogens, including streptococcal species that cause endocarditis. Although oropharyngeal microbes have been well described, viral communities are essentially uncharacterized. We conducted a metagenomic study to determine the composition of oropharyngeal DNA viral communities (both phage and eukaryotic viruses) in healthy individuals and to evaluate oropharyngeal swabs as a rapid method for viral detection. Viral DNA was extracted from 19 pooled oropharyngeal swabs and sequenced. Viral communities consisted almost exclusively of phage, and complete genomes of several phage were recovered, including Escherichia coli phage T3, Propionibacterium acnes phage PA6, and Streptococcus mitis phage SM1. Phage relative abundances changed dramatically depending on whether samples were chloroform treated or filtered to remove microbial contamination. pblA and pblB genes of phage SM1 were detected in the metagenomes. pblA and pblB mediate the attachment of S. mitis to platelets and play a significant role in S. mitis virulence in the endocardium, but have never previously been detected in the oral cavity. These genes were also identified in salivary metagenomes from three individuals at three time points and in individual saliva samples by PCR. Additionally, we demonstrate that phage SM1 can be induced by commonly ingested substances. Our results indicate that the oral cavity is a reservoir for pblA and pblB genes and for phage SM1 itself. Further studies will determine the association between pblA and pblB genes in the oral cavity and the risk of endocarditis.
authors.affiliation: Department of Biology, San Diego State University, San Diego, CA 92182, USA. willner9@aol.com
authors.forename: Dana
authors.initials: D
authors.lastname: Willner
authors.forename: Mike
authors.initials: M
authors.lastname: Furlan
authors.forename: Robert
authors.initials: R
authors.lastname: Schmieder
authors.forename: Juris A
authors.initials: JA
authors.lastname: Grasis
authors.forename: David T
authors.initials: DT
authors.lastname: Pride
authors.forename: David A
authors.initials: DA
authors.lastname: Relman
authors.forename: Florent E
authors.initials: FE
authors.lastname: Angly
authors.forename: Tracey
authors.initials: T
authors.lastname: McDole
authors.forename: Ray P
authors.initials: RP
authors.lastname: Mariella
authors.forename: Forest
authors.initials: F
authors.lastname: Rohwer
authors.forename: Matthew
authors.initials: M
authors.lastname: Haynes
mesh_terms: D001435:Bacteriophages / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D001792:Blood Platelets / Q000378:metabolism*; D002140:California; D019295:Computational Biology; D004696:Endocarditis / Q000821:virology*; D004926:Escherichia coli / Q000821:virology*; D005434:Flow Cytometry; D005814:Genes, Viral / Q000235:genetics; D006801:Humans; D056186:Metagenomics; D008969:Molecular Sequence Data; D009055:Mouth / Q000382:microbiology* / Q000821:virology; D010802:Phylogeny; D011425:Propionibacterium acnes / Q000821:virology*; D017422:Sequence Analysis, DNA; D034361:Streptococcus mitis / Q000821:virology*