Aggregation of 27 oral bacteria by human whole saliva

Abstract

Twenty-seven oral strains of the genera Actinomyces (5), Bacteroides (3), and Streptococcus (19) were tested for aggregation by human whole saliva, as well as the effect of culture medium, Ca-ions, and bacteria concentration thereupon. Of the media tested, GF-broth gave rise to less interference by autoaggregation or higher aggregation titers than BHI and TSB, and was used throughout this study. In most cases, Ca-ions (1 mM) only enhanced the rate of induced aggregation, whereas raising the bacteria concentration increased the rate of both induced- and autoaggregation. The final titers, ranging from 1-64, were hardly affected by these parameters, except those of S. rattus HG 59 and S. mutans HG 199, which were respectively increased and decreased by Ca-ions. Saliva-induced aggregation was observed for 21 strains of A. viscosus, A. naeslundii, A. israelii, B. gingivalis, B. intermedius, S. cricetus, S. mutans, S. rattus, S. sanguis, and S. sobrinus, mostly within 15 min to 3 h. Seventeen of these strains also showed autoaggregation, usually well after the onset of induced aggregation. Any potential induced aggregation of B. gingivalis HG 91 was always masked by autoaggregation, as well as that of the S. mutans strains under a particular set of conditions. The aggregation rate and titer varied considerably in a mutually unrelated and strain-dependent way. These microtiterplate data were matched by the 5 spectrophotometric patterns observed for saliva-bacterial interaction, which moreover, gave the better differentiation between induced and autoaggregation. In conclusion, most strains tested can show rapid saliva-induced aggregation in a strain-dependent way, yet strongly affected by the experimental conditions and interference from autoaggregation.

The effect of the flavonol morin on adhesion and aggregation of Streptococcus pyogenes

“…Research has demonstrated that large aggregate clumps are more easily detected by the innate immune system compared to those bacteria in biofilm or planktonic form (Ligtenberg et al, 1990;Kitada & Oho, 2010). Therefore, it is possible that flavonols could be used to prevent bacterial adhesion in the human host as a novel anti-adhesive compound, by virtue of its ability to promote aggregation and potentially facilitate bacterial clearance (Koop et al, 1989;Courtney & Hasty, 1991). Bacterial aggregation and biofilm development are intimately related.…”

Microradiographic study on the effects of salivary proteins on in vitro demineralization of bovine enamel

“…Based on macromolecular characteristics, the mucins in saliva can be divided into high (>1000 kDa) and low (<300 kDa) molecular weight forms (25). Saliva mucins are capable of aggregating selectively a number of oral microorganisms and mediate the adherence of oral microorganisms to the tooth surfaces (35). Moreover, mucins seem to contribute to the inhibition of demineralization against erosive attacks on enamel (36).…”

Adhesive interactions between medically important yeasts and bacteria

“…Spectrophotometric assays, classified as steady‐state and kinetic turbidimetric methods (Table 1), investigate coaggregation by a reduction in light absorbance in a spectrophotometer [24, 25]. These methods are simple, and can be quantitative, but again mass transport of the system is not controlled and frequently complicated by sedimentation.…”