Clonal analysis by ribotyping of Fusobacterium nucleatum isolates obtained from healthy young adults with optimal plaque control

Abstract

Fusobacterium nucleatum is a Gram‐negative anaerobic rod implicated in the pathogenesis of periodontal disease. However, this organism has also been frequently identified in high numbers in healthy adults. These observations suggest that the species may comprise different clonal types, some of which may participate in disease. The purpose of the present investigation was to use restriction endonuclease analysis (REA) and ribotyping to characterize F. nucleatum clonal types isolated from healthy young adults with optimal plaque control and investigate the stability of some of these clonal types. A group comprising 11 dental students and 11 dental outpatients with optimal plaque control was sampled. Clonal stability was investigated by sampling the dental student group at baseline and at 16 months. One hundred and thirty‐two clinical isolates of F. nucleatum were successfully recovered from 15/22 individuals. For the positive subjects, 29 different clonal types were identified by REA and ribotyping, each subject and site being colonized by 1‐4 clonal types. For the dental students, 9 and 15 different clonal types were identified at baseline and 16 months, respectively. None of the students harboured identical clonal types at both sampling times. Our results show that ribotyping is a useful technique for monitoring the distributions of F. nucleatum clonal types and indicate that healthy individuals with optimal plaque control can be colonized by more than one F. nucleatum clonal type and that these clonal types appear to be unstable.

Fusobacterium nucleatum

“…Emma Allen-Vercoe, 1 Jaclyn Strauss 1 and Kris Chadee 2, * 1 Molecular and Cellular Biology; University of Guelph; Guelph, ON; 2 Gastrointestinal Research Group; University of Calgary; Calgary, AB Canada F. nucleatum is a highly heterogeneous species and has been the subject of various schemes attempting to classify strains into subspecies or other groupings. [3][4][5][6] Currently, five subspecies are recognized; animalis, fusiforme, vincentii, polymorphum and nucleatum, although fusiforme is contested; phylogenetic and other groupings place it within the vincentii clade. 3,7 Phenotypically, however, classification of the F. nucleatum species is far from straightforward; antigenic determinants appear to be extremely heterogeneous even within a subspecies and even cell and colony morphology differs widely between genetically similar strains.…”

Fusobacterium nucleatum

“…Within the genus of Fusobacterium, there are presently 14 species characterized; many of these (including F. nucleatum) are familiar pathogens of humans and animals (Citron, 2002). F. nucleatum is known to be a highly heterogeneous species and has been the subject of different attempts to classify strains into subspecies or other groupings (Morris et al, 1997;Suchett-Kaye et al, 1998;Strauss et al, 2008). Currently, five subspecies are known: nucleatum, polymorphum, vincentii, fusiforme, and animalis.…”