title: A. actinomycetemcomitans profile and red complex bacterial species of an Afro-Brazilian community: A comparative study.
abstract: OBJECTIVE
  The primary aim of this cross-sectional study was to compare the levels of red complex bacteria between Afro-Brazilian and non Afro-Brazilian cohort. The secondary aim was to compare the distribution of both Aggregatibacter actinomycetemcomitans serotype b and its JP2 strains among participants who harboured this bacterial species.
  
  
  METHODS
  A total of 84 individuals were included in this study: 42 Afro-descendants (mean age 35.9 ± 13.1 years) and 42 non-Afro-descendants (mean age 36.2 ± 13.1 years) matched (1:1) by periodontal diagnosis, age and gender. All participants received clinical examinations of periodontal pocket depth, clinical attachment level, and plaque and gingival indices. Subgingival samples were taken for microbial analysis. First, genomic DNA (gDNA) was extracted and purified and the quantification of total number of bacterial cells, A. actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola was carried out by qPCR. Then, A. actinomycetemcomitans strains were classified according to serotype b and JP2 profiles by conventional PCR.
  
  
  RESULTS
  Clinically, mean PD, mean CAL and percentage of CAL ≥ 3 mm differed between groups (Student's t-test p<0.05). The levels of red complex bacteria between Afro-Brazilian and non-Afro-Brazilian populations were similar. The exception was verified to A. actinomycetemcomitans showing significantly higher levels among Afro-Brazilian descendants in comparison to non-Afro-Brazilian descendants. Afro-Brazilian descendants were clearly infected by more virulent serotype b and JP2 strains.
  
  
  CONCLUSIONS
  Despite no statistically significant differences related to the red complex species, Afro-Brazilian descendants harboured higher levels of A. actinomycetemcomitans. Also, our findings confirm that Afro-descendant populations are preferably colonised by A. actinomycetemcomitans serotype b as well as JP2 strains.
authors.affiliation: Dental School, Department of Periodontology, University of Taubaté, Rua Expedicionário Ernesto Pereira, 110 - Centro, Taubaté, SP, Brazil.
authors.forename: Murilo
authors.initials: M
authors.lastname: de Araujo Neris
authors.affiliation: Dental School, Nucleus of Periodontal Research, University of Taubaté, Rua Expedicionário Ernesto Pereira, 110 - Centro, Taubaté, SP, Brazil.
authors.forename: Sheila Cavalca
authors.initials: SC
authors.lastname: Cortelli
authors.affiliation: Dental School, Nucleus of Periodontal Research, University of Taubaté, Rua Expedicionário Ernesto Pereira, 110 - Centro, Taubaté, SP, Brazil.
authors.forename: Davi Romeiro
authors.initials: DR
authors.lastname: Aquino
authors.affiliation: Department of Biology, University of Taubaté, Rua Expedicionário Ernesto Pereira, 110 - Centro, Taubaté, SP, Brazil.
authors.forename: Taís Browne
authors.initials: TB
authors.lastname: de Miranda
authors.affiliation: Periodontal Department, Dental School, Federal University of Minas Gerais, Av. Antonio Carlos, 6.627 - Pampulha, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Fernando de Oliveira
authors.initials: Fde O
authors.lastname: Costa
authors.affiliation: Dental School, Nucleus of Periodontal Research, University of Taubaté, Rua Expedicionário Ernesto Pereira, 110 - Centro, Taubaté, SP, Brazil. Electronic address: jrcortelli@uol.com.br.
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Cortelli
mesh_terms: D000328:Adult; D016976:Aggregatibacter actinomycetemcomitans / Q000145:classification*; D001439:Bacteroides / Q000145:classification*; D044383:Black People; D001938:Brazil; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010518:Periodontitis / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D016966:Porphyromonas gingivalis / Q000145:classification; D012703:Serotyping; D048373:Treponema denticola / Q000145:classification
keywords: Bacteria; Ethnic groups; Leucotoxin; Periodontitis; Serotype