Horizontal Gene Transfer in Plasmid: Are We Close to Eliminating Periodontal Pathogens?

In clinical periodontal practice, patients with periodontitis frequently yield subgingival pathogens, resistant to therapeutic concentrations of commonly used antibiotics. The oral cavity is believed to provide excellent exogenous horizontal DNA transfer in dental plaque bacteria. Plasmids harness the replication, transcription, and translation systems of their host to ensure their continuity. While doing so, they burden their hosts' functionality. The non-specificity and inefficiency of current antibiotics and plasmid-mediated drug resistance is a major emerging challenge in dentistry. The literature reports that Actinobacllus actinomycetemcomitans, Fusobacterium nucleatum, Campylobacter, Streptococcus sp., and other periodontal pathogens are known to harbor native plasmids. The elimination of plasmids involves the inhibition of its replication in the “rolling circle” model. To the best of our knowledge, this paper is the first to discuss plasmid prevalence in periodontal microbiota. Furthermore, it also sheds light on plausible plasmid, curing that depends on 1) the chemical structure of curing compounds, 2) entry into the bacterial cell membrane, 3) prevention of the covalent binding of the Rep protein to the interns and Pcr A helices, and 4) inhibition of DNA gyrase might result in cessation of R-plasmid replication. By hindering plasmids rolling circular replication, it might be possible to reduce the spread of antimicrobial resistance genes and some virulence factors.