In vivo Colonization of Salivary Pellicle by Haemophilus, Actinomyces and Streptococcus Species

Abstract

Eight human subjects with healthy oral conditions were examined to study developing dental plaque. Supragingival plaque, buccal mucosa, tongue dorsum and saliva were sampled prior to the pumicing and cleaning of facial surfaces of the four upper premolars and two first molars. Samples were processed anaerobically on media that were selective for the oral Streptococcus spp., Haemophilus spp., and Actinomyces spp., as well as supplemented blood agar for identification of gram-negative bacterial groups and total cultivable flora. NAD-requiring Haemophilus spp., Streptococcus sanguis, Streptococcus mitis, Streptococcus mutans and Streptococcus salivarius were found in most oral samples. Analysis of the distribution of the Actinomyces spp., Actinomyces viscosus, Actinomyces naeslundii and Actinomyces odontolyticus in oral samples prior to teeth cleaning, found no significant differences between proportions or prevalence of these species in saliva, buccal mucosa, tongue, or pooled plaque samples. All three species were found on most surfaces in all subjects. Following cleaning, plaque was allowed to develop for 48 h. Proportions of a species in 2-hour plaque, when higher than proportions in the same individual’s saliva samples, were interpreted to be due to a species promotion by salivary pellicle (as 2-hour plaque from cleaned teeth). A median ratio of 1:3 of saliva versus 2-hour plaque was seen for A. odontolyticus suggesting some promotion by pellicle. A. viscosus and S. sanguis showed median ratios of saliva:2-hour plaque of 1:6 or higher, suggesting that salivary pellicle strongly promoted these species’ adherence. Developing plaques contained high proportions of streptococci, especially S. sanguis and S. mitis, as well as Haemophilus parainfluenzae. Significant increases were seen in proportions of S. sanguis in 48-hour versus 24-hour, and 2-hour plaques. A. viscosus, A. naeslundii and A. odontolyticus were found in most developing plaque samples and in similar proportions to each other. A significant twofold increase in proportions of A. odontolyticus, and fourfold increase of S. sanguis, was seen in 48- versus 2-hour plaques suggesting growth of these species. Forty-eight-hour plaque was composed primarily of Facklam type 1 S. sanguis and this species was found in significantly higher proportions than S. salivarius or S. mutans. NAD-requiring haemophili were found in high proportions and comprised 99% of the haemophili in 48-hour plaque. Although A. naeslundii was not dectected in as many 48-hour samples as A. viscosus or A. odontolyticus, these three species were found in similar proportions in 48-hour developing plaque samples.

Effect of Neuraminidase on the Adherence to Salivary Pellicle of Streptococcus sanguis and Streptococcus mitis

“…Similar adherence mecha nisms were also found for the S. mitis strains tested. These two species share several adherence character istics, although they do not occupy the same oral microhabitat [Liljemark and Gibbons, 1972;Clark et al, 1978;Cisar et al, 1979;Denepitiya and Klein berg, 1982;Boyd and McBride, 1984;Liljemark et al, 1986]. In vivo and in vitro studies should be continued to further define the additional character istics of S. sanguis which result in their predom inant role in developing and 'healthy' supragingival plaques.…”

“…lated from supragingival plaque on mitis salivarius agar (Difco La boratories, Detroit, Mich., USA) and speciated as previously de scribed [Carlsson, 1968;Facklam, 1977;Liljemark et al, 1986], All bacterial cultures were stored lyophilized and, when needed for as says, were grown from these stocks and were never transferred more than four successive times. Bacteria used in the adherence as says were grown in Todd-Hewitt broth (Difco) with 10 pCi/ml of 'H-thymidine added to radiolabel the cells.…”

“…Streptococcus sanguis and Streptococcus mitis are among the earliest colonizers of the tooth surface, with S. sanguis predominating [van Houteetal., 1970;Liljemark and Gibbons, 1972;Carlsson et al, 1975;Liljemark et al, 1986], Additional studies have shown that a continuing prominence, over time, of S. sanguis in human supragingival plaque has been associated clinically with increased caries resistance and with a healthy periodontium [Loesche et al, 1973;Bandt et al, 1982;Socransky etal., 1982;Loesche, 1986], Adherence of bacteria to a tooth surface plays a central role in plaque formation. The study of micro bial supragingival plaque ecology has centered on the adherence properties of oral streptococci and other indigenous species to experimental salivary pellicle [van Houte et al, 1970;Liljemark et al, 1978;Clark et al, 1978;Gibbons, 1980;Qureshi and Gibbons, 1981;Morris and McBride, 1984], The salivary macromole cules that have been shown to serve as receptors for streptococcal attachment to experimental pellicles are primarily oligosaccharide-containing glycoproteins [Gibbons andQureshi, 1978, 1979;Gibbons and Etherden, 1982;Murray et al, 1982;Stinson et al, 1982;Morris and McBride, 1984].…”

Salivary MUC5B-Mediated Adherence (Ex Vivo) of Helicobacter pylori During Acute Stress

“…However, the functions of saliva are not limited to the protection of the oral cavity because the mouth also serves as a reservoir and portal of entry for microorganisms that are active elsewhere in the body. These include several Streptococcus species (18), Hemophilus influenzae (19), Epstein-Barr virus, and her-pes simplex virus (20). Here, the role of saliva is not necessarily a protective one.…”

Human Oral Microbial Ecology and Dental Caries and Periodontal Diseases

“…It became apparent that earlier studies using this agar had erroneously included A. odontolyticus with the other Actinomyces. This elevated their numbers and incorrectly reported the magnitude of colonization of A. viscosus in supragingival plaques on smooth surfaces of enamel (Liljemark et al, 1986BloomquisUU/., 1996).…”