title: Analysis of genotypic variation in genes associated with virulence in Aggregatibacter actinomycetemcomitans clinical isolates.
abstract: OBJECTIVE
  Although certain serotypes of Aggregatibacter actinomycetemcomitans are associated more with aggressive periodontitis than are other serotypes, the correlation between distinct lineages and virulence traits in this species is poorly understood. This study aimed to evaluate the polymorphism of genes encoding putative virulence factors of clinical isolates, and to correlate these findings with A. actinomycetemcomitans serotypes, genotypes and periodontal status of the hosts.
  
  
  METHODS
  Twenty-six clinical isolates from diverse geographic populations with different periodontal conditions were evaluated. Genotyping was performed using pulse-field gel electrophoresis. Polymorphisms in the genes encoding leukotoxin, Aae, ApaH and determinants for serotype-specific O polysaccharide were investigated.
  
  
  RESULTS
  The isolates were classified into serotypes a-f, and exhibited three apaH genotypes, five aae alleles and 25 macrorestriction profiles. Two serotype b isolates (7.7%), obtained from Brazilian patients with aggressive periodontitis, were associated with the highly leukotoxic genotype; these isolates showed identical fingerprint patterns and aae and apaH genotypes. Serotype c, obtained from various periodontal conditions, was the most prevalent among Brazilian isolates, and isolates were distributed in two aae alleles, but formed a genetically distinct group based on apaH analysis. Cluster analysis showed a close relationship between fingerprinting genotypes and serotypes/apaH genotypes, but not with aae genotypes.
  
  
  CONCLUSIONS
  Apart from the deletion in the ltx promoter region, no disease-associated markers were identified. Non-JP2-like strains recovered from individuals with periodontal disease exhibited considerable genetic variation regarding aae/apaH genotypes, serotypes and XhoI DNA fingerprints.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Brazil.
authors.forename: E T
authors.initials: ET
authors.lastname: Pinheiro
authors.forename: D
authors.initials: D
authors.lastname: Kawamoto
authors.forename: C
authors.initials: C
authors.lastname: Ota-Tsuzuki
authors.forename: L R S
authors.initials: LR
authors.lastname: Almeida
authors.forename: A C R
authors.initials: AC
authors.lastname: Nunes
authors.forename: P L
authors.initials: PL
authors.lastname: Longo
authors.forename: M
authors.initials: M
authors.lastname: Wikstrom
authors.forename: M P A
authors.initials: MP
authors.lastname: Mayer
mesh_terms: D000189:Actinobacillus Infections / Q000382:microbiology*; D018829:Adhesins, Bacterial / Q000235:genetics; D016976:Aggregatibacter actinomycetemcomitans / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D010520:Aggressive Periodontitis / Q000382:microbiology; D000483:Alleles; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D020029:Base Pairing / Q000235:genetics; D055113:Chronic Periodontitis / Q000382:microbiology; D016172:DNA Fingerprinting; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics; D005098:Exotoxins / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D005838:Genotype; D006801:Humans; D019081:O Antigens / Q000235:genetics; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000382:microbiology; D010518:Periodontitis / Q000382:microbiology*; D010519:Periodontium / Q000382:microbiology; D011110:Polymorphism, Genetic / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012703:Serotyping; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001427:Bacterial Toxins; D005098:Exotoxins; D019081:O Antigens; D037521:Virulence Factors; C018579:leukotoxin; C034510:CTCGAG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific