title: The cagE gene sequence as a diagnostic marker to identify JP2 and non-JP2 highly leukotoxic Aggregatibacter actinomycetemcomitans serotype b strains.
abstract: OBJECTIVE
  Aggregatibacter actinomycetemcomitans is involved in oral and systemic infections, and is associated with, eg aggressive forms of periodontitis and with endocarditis. The cagE gene encodes a ≈39 kDa putative exotoxin expressed by A. actinomycetemcomitans. The level of conservation of cagE, and its possible significance in periodontal disease, has not yet been thoroughly investigated. In the present study, the role of the cagE gene as a diagnostic marker has been investigated.
  
  
  METHODS
  We have used conventional polymerase chain reaction (PCR), quantitative PCR and whole genome sequencing data to determine the prevalence of cagE in A. actinomycetemcomitans based on analysis of: (i) 249 isolates, collected and cultivated in a Ghanaian longitudinal cohort study; (ii) a serotype b collection of 19 strains; and (iii) the 36 A. actinomycetemcomitans genomes available in the NCBI database.
  
  
  RESULTS
  Whereas cagE was absent in the other serotypes, our data support that this gene sequence is linked to a virulent and highly leukotoxic group of serotype b strains, including both JP2 and non-JP2 genotypes of A. actinomycetemcomitans.
  
  
  CONCLUSIONS
  We propose that cagE has the potential to be used as a PCR-based gene marker for the identification of a virulent and highly leukotoxic group of serotype b strains, including both JP2 and non-JP2 genotypes. This finding might be of importance in the risk assessment of the development of periodontal attachment loss in young individuals and hence suggested to be a relevant discovery in future development of new diagnostic tools and/or treatment strategies.
authors.affiliation: Division of Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Johansson
authors.affiliation: Division of Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Claesson
authors.affiliation: Division of Molecular Periodontology, Department of Odontology, Umeå University, Umeå, Sweden.
authors.forename: C
authors.identifier: http://orcid.org/0000-0003-0765-6435
authors.initials: C
authors.lastname: Höglund Åberg
authors.affiliation: Section for Pediatric Dentistry, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.
authors.forename: D
authors.initials: D
authors.lastname: Haubek
authors.affiliation: Division of Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden.
authors.forename: J
authors.identifier: http://orcid.org/0000-0002-7948-9464
authors.initials: J
authors.lastname: Oscarsson
mesh_terms: D000293:Adolescent; D016976:Aggregatibacter actinomycetemcomitans / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D001427:Bacterial Toxins / Q000235:genetics*; D015415:Biomarkers; D002648:Child; D004269:DNA, Bacterial / Q000302:isolation & purification; D005098:Exotoxins / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics*; D005838:Genotype; D005869:Ghana; D006801:Humans; D008137:Longitudinal Studies; D017622:Periodontal Attachment Loss / Q000175:diagnosis / Q000382:microbiology; D010518:Periodontitis / Q000175:diagnosis* / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D018570:Risk Assessment; D065288:Serogroup; D000073336:Whole Genome Sequencing
chemical_list: D001427:Bacterial Toxins; D015415:Biomarkers; D004269:DNA, Bacterial; D005098:Exotoxins
keywords: 
  Aggregatibacter actinomycetemcomitans
  ; 
  cagE
  ; aggressive periodontitis; genotype; high leukotoxicity; virulence