Bacteriocin-producing oral streptococci and inhibition of respiratory pathogens

Abstract

The use of bacteria as probiotics is in continuous development, thanks to their capacity to maintain or restore a host's natural microbiome by interference with and/or inhibition of other microorganisms mediated by antimicrobial peptide production such as bacteriocins. In the oral cavity, Streptococcus salivarius, a non-pathogenic and predominant oral species, is one of the major bacteriocin producers that is able to coexist in this environment and reduce the frequency of colonization of the main pathogens involved in upper respiratory tract infections. The aim of this study was to screen oral bacteria colonizing healthy children for their use as potential oral probiotics. Eighty-one α-hemolytic streptococci isolated from nasal and/or pharyngeal swabs of 31 healthy children aged between two and twelve years were isolated. Among them, 13 α-hemolytic streptococci were selected for their bacteriocin-like inhibitory activity against potential pathogens. These strains were tested for bacteriocin production and assayed for their capacity to adhere to HEp-2 cell lines. Our data showed that 13 bacteriocin producer strains were able to inhibit different gram-positive pathogens. Among them one strain, S. salivarius 24SMB, deposited as DSM 23307, was selected as a potential oral probiotic, thanks to its safety assessment, ability to inhibit Streptococcus pneumoniae and the absence of virulence and antibiotic resistance genes.

Anti-Inflammatory Properties of Streptococcus salivarius, a Commensal Bacterium of the Oral Cavity and Digestive Tract

“…The S. salivarius TOVE-R strain has been reported to be a successful antagonist of virulent streptococci involved in tooth decay or pharyngitis, such as Streptococcus mutans, Streptococcus sobrinus, and Streptococcus pyogenes (19), or pathogens involved in periodontitis (20,21). The inhibitory activity toward S. pyogenes and Streptococcus pneumoniae has been attributed to bacteriocin production (22)(23)(24). In addition, S. salivarius was found to be able to affect immune responses by inhibiting inflammatory pathways activated by the pathogens, suggesting a role in the modulation of human epithelial cell immune responses (25,26).…”

Analysis of the Inhibitory Potential of Streptococcus Salivarius Isolated From Adult Saliva and the Tongue Dorsum for the Growth of Candida Albicans

“…Samples of 10 ml were taken from stimulated saliva using parafilm M and from the dorsum of subjects' tongues using a cytobrush from the circumvallate papillae to the end of the tongue [10]. The samples were cultured in an MSA medium, and selective media for Streptococci were used to colonize S. salivarius strain of Barbour and Philip and Santagati et al [11,12].…”

Characterization of bacteriocin bificin C6165: a novel bacteriocin

“…Such antimicrobial peptides are referred to as bacteriocin when they are produced by bacteria. The use of bacteriocins for food preservation has been a matter of extensive work in recent years (Todorov et al 2011;Ansari et al 2012;Cosentino et al 2012;Santagati et al 2012). Bifidobacteria are normal inhabitants of the human gastrointestinal tract throughout life.…”