Characterization of a new serotype g isolate of Aggregatibacter actinomycetemcomitans

K. Takada, M. Saito, O. Tsuzukibashi, Y. Kawashima, S. Ishida, M. Hirasawa

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40 Citations (Scopus)


Aggregatibacter actinomycetemcomitans is usually isolated from the oral cavity where it is associated with active periodontitis. The species can be divided into six serotypes (a-f) according to their surface carbohydrate antigens. However, some clinical isolates cannot be grouped within these six serotypes. Gram-negative, facultative anaerobic, catalase-positive coccobacilli were isolated from a patient with periodontitis and identified by employing genetic, biochemical and serological analyses. Phenotypic data identified the isolate as A. actinomycetemcomitans. Serotype-specific polysaccharide antigen from the isolate was untypeable by immunodiffusion testing in comparison with reference A. actinomycetemcomitans serotype a to f strains. Biofilm formation by the isolate was strong but cytotoxic activity was low. Gas chromatography/mass spectroscopy analysis of partially methylated alditol acetates from surface polysaccharide showed the presence of 2,4-di-O-methyl-rhamnose and 2,3,6-tri-O-methyl-glucose, with a 1 : 1 m ratio. The 1H- and 13C-nuclear magnetic resonance spectra of the antigen showed that both constituent glycoses had α-anomeric configuration. It is proposed that the untyped strain is a new A. actinomycetemcomitans serotype, designated serotype g.

Original languageEnglish
Pages (from-to)200-206
Number of pages7
JournalMolecular Oral Microbiology
Issue number3
Publication statusPublished - Jun 2010


  • A. actinomycetemcomitans
  • Adherence
  • Aggressive periodontitis
  • Polysaccharide antigen
  • Serotype


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