Antagonism of Bacteria from Dog Dental Plaque against Human Cariogenic Bacteria

Abstract

Dental caries are a process of demineralization and destruction of human teeth. They originate through many factors and are associated with biofilm formation, which consists of bacteria adhered to the teeth that form a structurally and functionally organized mass called dental plaque. Both the presence of Streptococcus mutans and the frequent consumption of sucrose correlate with a higher prevalence of caries in humans. In dogs, however, the incidence of this disease is low, due to factors such as differences in dental microbiota and/or their low consumption of sucrose. This work evaluated the antagonism of bacteria from dog's dental plaque against S. mutans, for the identification of producing strains of biotechnological products for use in preventing caries. This study used 95 bacterial isolates of canine dental plaque from the Veterinary Department at the Federal University of Viçosa, Minas Gerais, Brazil. A spot-on-the-lawn method was performed using Brain Heart Infusion agar with catalase for an initial identification of the antagonistic activity. Additional tests were conducted on the isolates classified as antagonists for confirmation of the activity, using modified Mann-Rogosa-Sharpe medium containing low dextrose concentration. These isolates were incubated at 37°C for 24 hours in anaerobiosis. The peptide nature of inhibition was evaluated using the following proteinases: proteinase K from Tritirachium album, bovine pancreatic trypsin, and type XII-A α-amylase from Bacillus licheniformis. In the initial identification of those strains exhibiting antimicrobial activity, 14 were classified as antagonists. One of the isolates (Bacillus sp.) indicated bacteriocinogenic activity, with a deformed inhibition halo on S. mutans by the addition of trypsin. These results suggest that this bacterial isolate may be applicable to biotechnological use to combat the main etiological agent of caries in humans. Further studies are needed to evaluate the bacteriocinogenic nature of the antimicrobial activities of the other 13 antagonistic bacterial isolates.

Inhibitory Effect of Bacillus licheniformis Strains Isolated from Canine Oral Cavity

“…In this study, all tested nCFS of B. licheniformis significantly inhibited the growth of S. mutans ATCC 35668, indicating the ability to produce antimicrobial substances. Similarly, in the study by Martins et al [ 42 ], Bacillus sp. isolated from canine dental biofilm showed bacteriocinogenic activity against S. mutans .…”

“…Compared to humans, the occurrence of dental caries in dogs is rare, probably due to the key factors such as differences in the oral microbiota composition, higher pH of saliva or the association with a low-carbohydrate diet. From this point of view, it is assumed that canine oral bacteria could be applied in the control of S. mutans and other cariogenic bacteria in human dental biofilms [ 42 ]. In this study, all tested nCFS of B. licheniformis significantly inhibited the growth of S. mutans ATCC 35668, indicating the ability to produce antimicrobial substances.…”

Natural Antimicrobials Promote the Anti-Oxidative Inhibition of COX-2 Mediated Inflammatory Response in Primary Oral Cells Infected with Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis

“…Periodontal disease and gum inflammation in dogs can be caused by pathogenic bacteria, with origins in the dental plaque [38]. Even though dental caries are unusual in dogs, bacteria such as E. faecalis is commonly present [39], and solutions to reduce the impact of dental plaque bacteria on oral health and biofilm formation is of increasing concern [17]. Herein we show that natural antimicrobials in mixtures can reduce the growth of S. aureus, S. pyogenes and E. faecalis, and can reduce their EPS production.…”