title: Phylogenetic variation of Aggregatibacter actinomycetemcomitans serotype e reveals an aberrant distinct evolutionary stable lineage.
abstract: The periodontal pathogen Aggregatibacter actinomycetemcomitans that comprises six serotypes (a-f), is often identified by PCR-based techniques targeting the 16S rRNA gene. In this study, 16S rRNA gene sequence analysis revealed an aberrant cluster of 19 strains within serotype e, denoted as serotype e'. The 16S rRNA gene sequence similarities found between serotype e' strains ranged from 99.7% to 100.0%, whereas 96.8-97.5% sequence similarity was obtained with members of the other serotypes, indicating that the serotype e' strains might not be true members of A. actinomycetemcomitans. However, DNA-DNA hybridizations between a representative serotype e' strain and representative strains of serotypes b, d and e of A. actinomycetemcomitans revealed 68-75% DNA-DNA relatedness, demonstrating that the serotype e' strains do belong to the species A. actinomycetemcomitans. AFLP analysis of 33 A. actinomycetemcomitans strains, representing all serotypes (a-f), but mainly serotype e' strains, showed that the latter form a distinct cluster, demonstrating that these strains are also closely related on the whole genome level. Moreover, the serotype e' strains were unable to ferment starch and glycogen in contrast to almost all other A. actinomycetemcomitans strains tested. Overall, the data obtained in this study suggest that the serotype e' strains form an evolutionary relatively stable distinct subgroup within A. actinomycetemcomitans.
authors.affiliation: Department of Oral Microbiology, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit, Van der Boechorststraat 7, NL-1081 BT Amsterdam, The Netherlands. wa.vanderreijden@vumc.nl
authors.forename: Wil A
authors.initials: WA
authors.lastname: van der Reijden
authors.forename: Jorg
authors.initials: J
authors.lastname: Brunner
authors.forename: Carolien J
authors.initials: CJ
authors.lastname: Bosch-Tijhof
authors.forename: Stefanie
authors.initials: S
authors.lastname: van Trappen
authors.forename: Martine C
authors.initials: MC
authors.lastname: Rijnsburger
authors.forename: Marcel P W
authors.initials: MP
authors.lastname: de Graaff
authors.forename: Arie J
authors.initials: AJ
authors.lastname: van Winkelhoff
authors.forename: Ilse
authors.initials: I
authors.lastname: Cleenwerck
authors.forename: Paul
authors.initials: P
authors.lastname: de Vos
mesh_terms: D001483:Base Sequence; D050260:Carbohydrate Metabolism; D004269:DNA, Bacterial; D019143:Evolution, Molecular; D005285:Fermentation; D014644:Genetic Variation; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D015661:Pasteurellaceae / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012703:Serotyping
chemical_list: D004269:DNA, Bacterial