Stress as a Determinant of Saliva-Mediated Adherence and Coadherence of Oral and Nonoral Microorganisms

Abstract

Objective: The mucosal secretory proteins, such as the salivary proteins, play a key role in the acquisition and regulation of the mucosal microflora. Most notably, some microorganisms utilize the host's secretory proteins to adhere to the mucosa; a first step in colonization and infection. The secretory proteins also influence colonization by affecting the binding among microorganisms, a process denoted as coadherence. Previously we reported that acute stressors cause specific changes in saliva composition. The present study investigated to what extent these changes influence saliva-mediated microbial adherence and coadherence (ex vivo). Methods: Thirty-two male undergraduates provided unstimulated saliva before and during a control condition and two stressors: A memory test and a surgery video presentation. We used saliva-coated microplates to test the adherence of bacteria for which the oral cavity is either a natural reservoir (eg, viridans streptococci) or a portal of entry (eg, Helicobacter pylori). We also tested the saliva-mediated co-adherence between Streptococcus gordonii and the yeast Candida albicans. Correlation analyses were performed to determine the relationships between changes in microbial adherence and the concentrations of potential salivary ligands, viz. cystatin S, the mucins MUC5B and MUC7, S-IgA, lactoferrin, ␣-amylase, and total salivary protein. Results: During the memory test, saliva-mediated adhesion of Streptococcus sanguis, Streptococcus gordonii, and H. pylori increased, whereas the coadherence of C. albicans with S. gordonii decreased. During the surgical video presentation the saliva-mediated adherence of H. pylori, S. sanguis, and Streptococcus mitis increased. These changes were independent of salivary flow rate, but correlated with specific changes in salivary protein composition. Conclusion: The results show that even moderate stressors, by altering the activity of the mucosal secretory glands, may affect microbial colonization processes such as adherence and coadherence. This study hereby presents a mechanism by which stress may affect the mucosal microflora and susceptibility to infectious disease.

Candida spp. adherence to oral epithelial cells and levels of IgA in children with orthodontic appliances

“…Among the many factors that contribute to the higher prevalence of C. albicans in the oral cavity are its excellent ability to adhere and the presence of many cell receptors, which confer versatility and resistance to removal by the fluids that bathe these surfaces. 8 In this study, patients in the EG had a higher incidence of non-albicans species in saliva as compared with patients in the CG. Several studies have reported that predisposing factors such as mouth breathing 12 and HIV-infection 13 may increase the variability of Candida species in the oral cavity.…”

“…Our finding that the EG had higher counts of adhering Candida suggests that the use of orthodontic devices may cause stress or microtrauma in the oral mucosa that can affect the process of microbial colonization and the adherence of yeasts to epithelial cells. 8 C. albicans was the species most frequently isolated from the oral cavities of patients in both groups, followed by C. tropicalis. Among the many factors that contribute to the higher prevalence of C. albicans in the oral cavity are its excellent ability to adhere and the presence of many cell receptors, which confer versatility and resistance to removal by the fluids that bathe these surfaces.…”

“…C. albicans exhibits the highest values of adherence to oral epithelial cells relative to other Candida species. Bosh et al 8 verified that moderate stress may affect the process of microbial colonization and the adherence of C. albicans to epithelial cells by altering the secretory activity of salivary glands.…”

Roles of Different Sources of Social Support on Caries Experience and Caries Increment in Adolescents of East London

“…Furthermore, social support may affect health by influencing physiological processes related to the stress response, including changes in cardiovascular, neuroendocrine and immune function [Uchino et al, 1996;Uchino, 2006]. Evidence suggests that stress affects salivary flow rate and the production of salivary immunoglobulin A, which together are thought to have multiple protective functions against dental caries including interference with microbial colonisation processes and possible inhibition of metabolic activities [Russell et al, 1999;Bergdahl and Bergdahl, 2000;Bosch et al, 2003;Teeuw et al, 2004]. Further research is needed to assess the roles of psychological and physiological mechanisms in explaining the relationship between social support and dental caries.…”

Depressive Symptoms and Untreated Dental Caries in Older Independently Living South Brazilians

“…This effect of psychological reactions on oral bacterial counts is believed to be mediated by changes on salivary secretory immunity. In fact, previous evidence has shown that chronic stress is able to downregulate the secretion of salivary immunoglobulin A [Phillips et al, 2006], the main adaptive immune mechanism in the oral cavity, while moderate stressors are able to increase the in vitro saliva-mediated adherence of oral bacteria, which in turn favors the formation of dental biofilm [Bosch et al, 2003].…”