Bacteriophages often constitute the majority of periodontal viral communities, but phages that infect oral bacteria remain uncharacterized. Here, we present the genetic analysis of the genome of a novel siphovirus, named Siphoviridae_29632, which was isolated from a patient with periodontitis using a viral metagenomics-based approach. Among 43 predicted open reading frames (ORFs) in the genome, the viral genes encoding structural proteins were distinct from the counterparts of other viruses, although a distant homology is shared among viral morphogenesis proteins. A total of 28 predicted coding sequences had significant homology to other known phage ORF sequences. In addition, the prevalence of Siphoviridae_29632 in a cohort of patients with chronic periodontitis was 41.67%, which was significantly higher than that in the healthy group (4.55%, P < 0.001), suggesting that this virus as well as its hosts may contribute to the ecological environment favored for chronic periodontitis.
Keywords: Bacteriophage; Case–control study; Periodontitis; Siphovirus; Viral metagenomics.