title: The mycobiome of root canal infections is correlated to the bacteriome.
abstract: OBJECTIVE
  Bacterial infection of the root canal system causes apical periodontitis. Less is known about the role of fungi in these infections. This study aimed to assess the fungal prevalence, abundance, and diversity of root canal infections, as well as the relation between fungi and bacteria present in different parts of the root canal.
  
  
  METHODS
  Twenty-six teeth with primary apical periodontitis were extracted, split in apical and coronal root segments, and cryo-pulverized. Bacteriome profiles of 23 teeth were analyzed based on the V3-V4 hypervariable region of the 16S ribosomal RNA gene. Mycobiome profiles of six teeth were analyzed based on the internal transcribed spacer (ITS) 1 or ITS2 region. Samples were sequenced on the Illumina MiSeq platform.
  
  
  RESULTS
  A total of 338 bacterial operational taxonomic units (OTUs), 28 ITS1 OTUs, and 24 ITS2 OTUs were identified. Candida and Malassezia were the most frequently identified fungi. No differences could be found between the bacteriome and mycobiome profiles of the apical and coronal root segments. The bacteriome of fungi-positive root segments contained more Actinomyces, Bifidobacterium, four different Lactobacillus OTUs, Propionibacterium, and Streptococcus. A Spearman correlation matrix between bacteriomes and mycobiomes identified no correlations, but separate clusters could be observed.
  
  
  CONCLUSIONS
  A considerable proportion of the root canal infections contain fungi, although fungal diversity is limited. However, when fungi are present, the composition of the bacteriome is clearly different.
  
  
  CONCLUSIONS
  Interaction between bacteria and fungi in root canal infections may complicate the infection and require alternative treatment strategies.
authors: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081, LA, Amsterdam, The Netherlands. i.persoon@acta.nl.
authors: Ilona F
authors: IF
authors: Persoon
authors: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081, LA, Amsterdam, The Netherlands.
authors: Mark J
authors: MJ
authors: Buijs
authors: Department of Endodontology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081, LA, Amsterdam, The Netherlands.
authors: Ahmet R
authors: AR
authors: Özok
authors: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081, LA, Amsterdam, The Netherlands.
authors: Wim
authors: W
authors: Crielaard
authors: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081, LA, Amsterdam, The Netherlands.
authors: Bastiaan P
authors: BP
authors: Krom
authors: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081, LA, Amsterdam, The Netherlands.
authors: Egija
authors: E
authors: Zaura
authors: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081, LA, Amsterdam, The Netherlands.
authors: Bernd W
authors: BW
authors: Brandt
mesh_terms: D001419:Bacteria / Q000145:classification*; D004269:DNA, Bacterial / Q000032:analysis; D004271:DNA, Fungal / Q000032:analysis; D006801:Humans; D066298:In Vitro Techniques; D000072761:Mycobiome; D010485:Periapical Periodontitis / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S
chemical_list: D004269:DNA, Bacterial; D004271:DNA, Fungal; D012336:RNA, Ribosomal, 16S
keywords: Bacteria; Fungi; Microbiome; Next-generation sequencing; Primary endodontic infection