A gene cluster for the synthesis of serotype g-specific polysaccharide antigen in Aggregatibacter actinomycetemcomitans

Osamu Tsuzukibashi, Masanori Saito, Taira Kobayashi, Koji Umezawa, Fumio Nagahama, Takachika Hiroi, Masatomo Hirasawa, Kazuko Takada

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11 Citations (Scopus)


Aggregatibacter actinomycetemcomitans is an important pathogen related to aggressively progressive periodontal breakdown in adolescents and adults. The species can be divided into six serotypes (a-f) according to their surface carbohydrate antigens. Recently, a new serotype g of A. actinomycetemcomitans was proposed. The aim of the present study was to sequence the gene cluster associated with the biosynthesis of the serotype g-specific polysaccharide antigen and develop serotype-specific primers for PCR assay to identify serotype g strains of A. actinomycetemcomitans. The serotype-specific polysaccharide (SSPS) gene cluster of the NUM-Aa 4039 strain contained 21 genes in 21,842-bp nucleotides. The similarity of the SSPS gene cluster sequence was 96.7 % compared with that of the serotype e strain. Seventeen serotype g genes showed more than 90 % homology both in nucleotide and amino acids to the serotype e strain. Three additional genes with 1,579 bp in NUM-Aa 4039 were inserted into the corresponding ORF13 of the serotype e strain. The serotype g-specific primers were designed from the insertion region of NUM-Aa 4039. Serotypes of the a-f strains were not amplified by serotype-specific g primers; only NUM-Aa 4039 showed an amplicon band. The NUM-Aa 4039 strain was three genes in the SSPS gene cluster different from those of serotype e strain. The specific primers derived from these different regions are useful for identification and distribution of serotype g strain among A. actinomycetemcomitans from clinical samples.

Original languageEnglish
Pages (from-to)261-265
Number of pages5
JournalArchives of Microbiology
Issue number4
Publication statusPublished - Apr 2014


  • A. actinomycetemcomitans
  • PCR
  • Polysaccharide gene cluster
  • Serotype g


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