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.
Highlights
Dental caries is a multifactorial disease, where microbial involvement and the host response are both of fundamental importance
From the 95 isolates tested in the initial evaluation of the antagonistic activity, 14 formed inhibition halos around the colonies in the Brain Heart Infusion (BHI) agar medium containing a catalase solution
These isolates were initially classified as antagonists against S. mutans and/or S. aureus
Summary
Dental caries is a multifactorial disease, where microbial involvement and the host response are both of fundamental importance. The differences in a dog’s dental microbiota, their poor sucrose consumption [10, 11], or the possibility of microorganisms present in the oral cavity could establish antagonism on S. mutans and other cariogenic bacteria This antagonism results from competition for nutrients or production of compounds inhibitory to these bacteria, bacteriocins, which would develop a critical barrier against colonization by pathogenic species [1]. Numerous lactic acid bacteria are consistently found in the dental plaque of dogs; many of these have the capacity to produce bacteriocins against similar bacteria in order to establish their colonization sites [7,8,9] This ability to inhibit target strains is potentially useful in food preservation and the production of alternative antimicrobial therapeutic agents for diseased sites [15,16,17,18]. The work presented here furthers the development of anticaries products through evaluating the antagonism of bacterial isolates from canine dental plaques against S. mutans to identify strains that produce compounds with biotechnological potential
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
