Dynamic Changes in the Initial Colonization of Actinomyces naeslundii and Streptococcus gordonii Using a New Animal Model

Abstract

SUMMARY: Actinomyces naeslundii and Streptococcus gordonii are the predominant bacteria and initial colonizers of oral microflora. The binding of A. naeslundii and S. gordonii and the interaction between them on the salivary pellicle-coated tooth surface play an important role in the biofilm development. Recently, we reported that NOD/SCID.e2f1 -mice are a useful model for studying oral biofilm formation by Streptococcus mutans on the tooth surface. In this study, we aimed to determine whether NOD/SCID.e2f1 -mice can be used for studying oral colonization of A. naeslundii and S. gordonii. Colonization of A. naeslundii in mice fed with 1z sucrose water for 24 h before inoculation was higher than that among mice fed with sucrose water for 1 h. A. naeslundii colonization using mixed speciesinoculation was lower than that using single-species inoculation 30-90 min after inoculation; however, the colonization was higher 120-180 min after inoculation. The mixed inoculation induced better colonization of S. gordonii than single-species inoculation 60-180 min after inoculation. Polyclonal and fluorescein isothiocyanate-labeled antibody stained bacteria showed better colonization of S. gordonii when a mixed culture is used in vivo. NOD/SCID.e2f1 -mice were useful for studying the initial colonization of A. naeslundii and S. gordonii. Long-term supply of sucrose water creates a favorable environment for the initial colonization of A. naeslundii that, in turn, supports the colonization of S. gordonii.

The inhibitory effect of quaternary ammonium salt on bacteria in root canal

“…naeslundii , S . gordonii forms stable coaggregation partnership, develops strong intergeneric communications, colonizes better than in mono-species biofilm 19 , and A . naeslundii could protect S .…”

Oral Biosciences: The annual review 2014

“…Investigations have revealed the following: (1) NOD/SCID.E2f1 À / À mice demonstrate dry mouth characteristics, (2) NOD/SCID.E2f1 À / À mice have more ducts in the salivary glands than NOD/SCID mice, and (3) diffuse localization, ubiquitination, and reduction of expression of AQP5 are observed in the salivary gland cells of NOD/SCID.E2f1 À / À mice. Recent papers have reported how NOD/ SCID.E2f1 À / À mice can be employed for the study of the initial colonization by streptococci, Actinomyces naeslundii and Candida albicans, that occurs as a result of the dry mouth trait [8][9][10]. The NOD/SCID.E2f1 À / À mice have wide potential application to studies on not only dry mouth, but also oral diseases related to hyposalivation.…”

Expression and diversity of the sialic acid–binding adhesin and its homologs associated with oral streptococcal infection

“…Hsa binds to sialoglycoconjugates, such as the salivary mucin MG2, 14,15 and thus, contributes to biofilm formation on the saliva-coated surface, 16 which is thought to be involved in the pathogenesis of dental caries and periodontal diseases. 9,17,18 Hsa also contributes to the pathogenesis of experimental infective endocarditis caused by S. gordonii DL1. 19 Hsa and its homologs facilitate S. gordonii attachment to host cells, including polymorphonuclear leukocytes, 20,21 erythrocytes, 22,23 platelets, [24][25][26][27] macrophages, and monocytes.…”

“…The sialic acid–binding adhesin of the Streptococcus gordonii wild‐type strain DL1, also known as Hsa, has been found as a bacterial cell surface fibrillar antigen associated with hemagglutinating (HA) activity. Hsa binds to sialoglycoconjugates, such as the salivary mucin MG2, 14,15 and thus, contributes to biofilm formation on the saliva‐coated surface, 16 which is thought to be involved in the pathogenesis of dental caries and periodontal diseases 9,17,18 . Hsa also contributes to the pathogenesis of experimental infective endocarditis caused by S .…”