title: Viral-bacterial associations in acute apical abscesses.
abstract: OBJECTIVE
  Viral-bacterial and bacterial synergism have been suggested to contribute to the pathogenesis of several human diseases. This study sought to investigate the possible associations between 9 candidate endodontic bacterial pathogens and 9 human viruses in samples from acute apical abscesses.
  
  
  METHODS
  DNA extracts from purulent exudate aspirates of 33 cases of acute apical abscess were surveyed for the presence of 9 selected bacterial species using a 16S ribosomal RNA gene-based nested polymerase chain reaction (PCR) approach. Single or nested PCR assays were used for detection of the human papillomavirus (HPV) and herpesviruses types 1 to 8.
  
  
  RESULTS
  Two-thirds of the abscess samples were positive for at least one of the target viruses. Specifically, the most frequently detected viruses were HHV-8 (54.5%); HPV (9%); and varicella zoster virus (VZV), Epstein-Barr virus (EBV), and HHV-6 (6%). Bacterial DNA was present in all cases and the most prevalent bacterial species were Treponema denticola (70%), Tannerella forsythia (67%), Porphyromonas endodontalis (67%), Dialister invisus (61%), and Dialister pneumosintes (57.5%). HHV-8 was positively associated with 7 of the target bacterial species and HPV with 4, but all these associations were weak. Several bacterial pairs showed a moderate positive association. Viral coinfection was found in 6 abscess cases, but no significant viral association could be determined.
  
  
  CONCLUSIONS
  Findings demonstrated that bacterial and viral DNA occurred concomitantly in two-thirds of the samples from endodontic abscesses. Although this may suggest a role for viruses in the etiology of apical abscesses, the possibility also exists that the presence of viruses in abscess samples is merely a consequence of the bacterially induced disease process. Further studies are necessary to clarify the role of these viral-bacterial interactions, if any, in the pathogenesis of acute apical abscesses.
authors.affiliation: Institute of Microbiology Prof Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Dennis C
authors.initials: DC
authors.lastname: Ferreira
authors.forename: Isabela N
authors.initials: IN
authors.lastname: Rôças
authors.forename: Simone S M
authors.initials: SS
authors.lastname: Paiva
authors.forename: Flávia L
authors.initials: FL
authors.lastname: Carmo
authors.forename: Fernanda S
authors.initials: FS
authors.lastname: Cavalcante
authors.forename: Alexandre S
authors.initials: AS
authors.lastname: Rosado
authors.forename: Kátia R N
authors.initials: KR
authors.lastname: Santos
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
mesh_terms: D000293:Adolescent; D000328:Adult; D016866:Bacteroidaceae Infections / Q000382:microbiology; D001442:Bacteroides Infections / Q000382:microbiology; D004269:DNA, Bacterial / Q000032:analysis; D004279:DNA, Viral / Q000032:analysis; D020031:Epstein-Barr Virus Infections / Q000821:virology; D016965:Gram-Negative Anaerobic Straight, Curved, and Helical Rods / Q000145:classification; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D006562:Herpes Zoster / Q000821:virology; D006564:Herpesviridae / Q000145:classification; D006566:Herpesviridae Infections / Q000821:virology*; D015654:Herpesvirus 6, Human / Q000302:isolation & purification; D019288:Herpesvirus 8, Human / Q000302:isolation & purification; D006801:Humans; D008875:Middle Aged; D030361:Papillomavirus Infections / Q000821:virology; D010482:Periapical Abscess / Q000382:microbiology* / Q000821:virology; D016133:Polymerase Chain Reaction; D016966:Porphyromonas gingivalis / Q000302:isolation & purification; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D019349:Roseolovirus Infections / Q000821:virology; D048373:Treponema denticola / Q000302:isolation & purification; D014211:Treponemal Infections / Q000382:microbiology; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D004279:DNA, Viral; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S