The human oral phageome

Abstract

The human oral cavity harbors complex and diverse biofilms on tooth enamel, periodontal tissues, the tongue, buccal mucosa, hard and soft palates, and the lips. Oral bacteria may also seed to tonsils, pharynx, and esophagus. Oral microbiomes support large populations of viruses, mostly bacteriophages (phages) that infect specific bacterial species, and can appear as free phage virions (phage particles) or as dormant prophages (in bacterial lysogens). [1][2][3][4] A 1 μl volume of saliva may harbor as many as 100,000 virus-like particles, most of which are phages. 5,6 This article reviews the diversity of the oral phageome and the potential impact of phages on the ecology and dynamics of dental biofilms, with emphasis on the phage interaction with periodontopathic bacteria. The potential utility of phage therapy in oral health care is highlighted as well. | BA S IC FE ATURE S OF BAC TERI OPHAG E SPhages comprise a significant part of virtually all human and environmental microbiomes, and they may modulate the formation and ecology of such microbiotas. 1,2,6,7 Phages are used for fingerprinting of bacterial strains (known as phage typing), food biopreservation, pathogen detection, and treatment of bacterial diseases of humans, animals, and plants. [8][9][10][11][12] The continual increase in multiple-drug resistance among bacterial pathogens has created a need for new approaches to combat infectious diseases. An intriguing aspect of lytic phages is their ability to kill specific bacterial pathogens without upsetting the beneficial commensal microbiota, without causing superinfections by antibiotic-resistant microorganisms, and without inducing adverse drug reactions. Phage therapy may be particularly important for treatment of oral biofilm microorganisms, which can show resistance to common antibiotics and antiseptics. Also, phages or their enzymes may be used to edit the human microbiome toward a health-preserving state and to interact directly with human immune cells to modulate human immune responses. 3,13,14 Prophages can also transfer genetic traits or cause genome excision of bacterial genes, which may confer novel properties to the bacteria. 15,16 The life-threatening toxins of Vibrio cholerae, Escherichia coli, Corynebacterium diphtheriae, and Clostridium botulinum are examples of prophage-encoded virulence factors. 15,16 Phage classification is based on morphology, infectious cycle and genomic content. 4,[20][21][22][23][24][25][26][27][28][29][30][31] Phages can have a tailed proteinaceous capsid with a double-stranded deoxyribonucleic acid (DNA) genome or a nontailed capsid with either double-stranded DNA, single-stranded DNA, or ribonucleic acid (RNA) genomes (Figure 1). Filamentous and pleomorphic phages also exist. Tailed bacteriophages (classified in the order Caudovirales) make up 96% of all phage isolates and are divided into families based on the tail morphology. Large virions (phage particles) with a long contractile tail belong to the families Myoviridae (mostly), Ackermannviridae, or Herellevir...

The clinical association between Periodontitis and COVID-19

“…Most research currently seems to have been concentrated on verifying whether the presence of periodontal disease affects COVID-19-related outcomes. It would, however, be interesting to see whether there exists the possibility of crosstalk between the SARS-CoV-2 and the oral microbiome either directly or in a phage-mediated manner [47,48].…”

SARS-CoV-2 infection reduces human nasopharyngeal commensal microbiome with inclusion of pathobionts

“…The respiratory tract microbiomes support large populations of viruses, mostly bacteriophages (phages) that infect specific bacterial species, and can appear as free phage virions (phage particles) or as dormant prophages. Since most secondary bacterial infections occur in immunocompromised or immunodeficient SARS-CoV-2 patients, phages can induce immune responses these patients 46 . The archaeal fraction of the human nasopharyngeal microbiomes across three metagenomes were predominated by different methanogenic and thermophilic genera.…”

Bacterial swarm-mediated phage transportation disrupts a biofilm inherently protected from phage penetration

“…Hence, microbubbles move It is predicted that around 10 12 phages reside in the human gut 46 . Phages are abundant in the human oral microbiota and a 1 µL volume of saliva contains 100,000 virus-like particles 47 . Capnocytophaga isolates from the human oral cavity are robustly motile 48 and as we now know, they transport phages (Fig.…”