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John R Tagg - One of the best experts on this subject based on the ideXlab platform.

  • In vitro Inhibition of Clinical Isolates of Otitis Media Pathogens by the Probiotic Streptococcus salivarius BLIS K12
    Probiotics and Antimicrobial Proteins, 2020
    Co-Authors: Tzu Yu Chen, John R Tagg, John D F Hale, Rohit Jain, Abigail L. Voss, Nikki Mills, Emma J. Best, Duncan S. Stevenson, Philip A. Bird, Tony Walls
    Abstract:

    Otitis media is a common childhood infection, frequently requiring antibiotics. With high rates of antibiotic prescribing and increasing antibiotic resistance, new strategies in otitis media prevention and treatment are needed. The aim of this study was to assess the in vitro inhibitory activity Streptococcus salivarius BLIS K12 against otitis media pathogens. Efficacy of the bacteriocin activity of S. salivarius BLIS K12 against the otitis media isolates was assessed using the deferred antagonism test. Overall, 48% of pathogenic isolates exhibited some growth inhibition by S. salivarius BLIS K12. S. salivarius BLIS K12 can inhibit the in vitro growth of the most common pathogens.

  • a taqman based quantitative pcr screening assay for the probiotic Streptococcus salivarius k12 based on the specific detection of its megaplasmid associated salivaricin b locus
    Journal of Microbiological Methods, 2020
    Co-Authors: Peter Reid, Nicholas C. K. Heng, John R Tagg, John D F Hale, Julian Crane, Deepti Krishnan, Trudy J Milne
    Abstract:

    In order to assess the colonization efficacy of the oral probiotic Streptococcus salivarius K12, a rapid method for specific detection and enumeration of the strain was developed. Here, we describe a two-step TaqMan™ quantitative PCR assay using primer-probe combinations targeting genes of the locus encoding the lantibiotic bacteriocin salivaricin B.

  • investigation of Streptococcus salivarius mediated inhibition of pneumococcal adherence to pharyngeal epithelial cells
    BMC Microbiology, 2016
    Co-Authors: John R Tagg, Philip A Wescombe, John D F Hale, Jayne Manning, Eileen M Dunne, Kim E Mulholland, Roy M Robinsbrowne
    Abstract:

    Background Pneumococcal adherence to the nasopharyngeal epithelium is a critical step in colonisation and disease. The probiotic bacterium, Streptococcus salivarius, can inhibit pneumococcal adherence to epithelial cells in vitro. We investigated the mechanism(s) of inhibition using a human pharyngeal epithelial cell line (Detroit 562) following pre-administration of two different strains of S. salivarius.

  • Streptococcus salivarius k12 limits group b Streptococcus vaginal colonization
    Infection and Immunity, 2015
    Co-Authors: Kathryn A Patras, John R Tagg, Philip A Wescombe, John D F Hale, Berenice Rosler, Kelly S Doran
    Abstract:

    Streptococcus agalactiae (group B Streptococcus [GBS]) colonizes the rectovaginal tract in 20% to 30% of women and during pregnancy can be transmitted to the newborn, causing severe invasive disease. Current routine screening and antibiotic prophylaxis have fallen short of complete prevention of GBS transmission, and GBS remains a leading cause of neonatal infection. We have investigated the ability of Streptococcus salivarius, a predominant member of the native human oral microbiota, to control GBS colonization. Comparison of the antibacterial activities of multiple S. salivarius strains by use of a deferred-antagonism test showed that S. salivarius strain K12 exhibited the broadest spectrum of activity against GBS. K12 effectively inhibited all GBS strains tested, including disease-implicated isolates from newborns and colonizing isolates from the vaginal tract of pregnant women. Inhibition was dependent on the presence of megaplasmid pSsal-K12, which encodes the bacteriocins salivaricin A and salivaricin B; however, in coculture experiments, GBS growth was impeded by K12 independently of the megaplasmid. We also demonstrated that K12 adheres to and invades human vaginal epithelial cells at levels comparable to GBS. Inhibitory activity of K12 was examined in vivo using a mouse model of GBS vaginal colonization. Mice colonized with GBS were treated vaginally with K12. K12 administration significantly reduced GBS vaginal colonization in comparison to nontreated controls, and this effect was partially dependent on the K12 megaplasmid. Our results suggest that K12 may have potential as a preventative therapy to control GBS vaginal colonization and thereby prevent its transmission to the neonate during pregnancy.

  • developing oral probiotics from Streptococcus salivarius
    Future Microbiology, 2012
    Co-Authors: Philip A Wescombe, Nicholas C. K. Heng, John D F Hale, John R Tagg
    Abstract:

    Considerable human illness can be linked to the development of oral microbiota disequilibria. The predominant oral cavity commensal, Streptococcus salivarius has emerged as an important source of safe and efficacious probiotics, capable of fostering more balanced, health-associated oral microbiota. Strain K12, the prototype S. salivarius probiotic, originally introduced to counter Streptococcus pyogenes infections, now has an expanded repertoire of health-promoting applications. K12 and several more recently proposed S. salivarius probiotics are now being applied to control diverse bacterial consortia infections including otitis media, halitosis and dental caries. Other potential applications include upregulation of immunological defenses against respiratory viral infections and treatment of oral candidosis. An overview of the key steps required for probiotic development is also presented.

Jeremy P Burton - One of the best experts on this subject based on the ideXlab platform.

  • salivaricin g32 a homolog of the prototype Streptococcus pyogenes nisin like lantibiotic sa ff22 produced by the commensal species Streptococcus salivarius
    International Journal of Microbiology, 2012
    Co-Authors: Philip A Wescombe, Jeremy P Burton, Kristin H Dyet, Karen P Dierksen, Daniel A Power, Ralph W Jack, Megan A Inglis, Anna L Wescombe, John R Tagg
    Abstract:

    Salivaricin G32, a 2667 Da novel member of the SA-FF22 cluster of lantibiotics, has been purified and characterized from Streptococcus salivarius strain G32. The inhibitory peptide differs from the Streptococcus pyogenes—produced SA-FF22 in the absence of lysine in position 2. The salivaricin G32 locus was widely distributed in BLIS-producing S. salivarius, with 6 (23%) of 26 strains PCR-positive for the structural gene, slnA. As for most other lantibiotics produced by S. salivarius, the salivaricin G32 locus can be megaplasmid encoded. Another member of the SA-FF22 family was detected in two Streptococcus dysgalactiae of bovine origin, an observation supportive of widespread distribution of this lantibiotic within the genus Streptococcus. Since the inhibitory spectrum of salivaricin G32 includes Streptococcus pyogenes, its production by S. salivarius, either as a member of the normal oral microflora or as a commercial probiotic, could serve to enhance protection of the human host against S. pyogenes infection.

  • genome sequence of the bacteriocin producing oral probiotic Streptococcus salivarius strain m18
    Journal of Bacteriology, 2011
    Co-Authors: Nicholas C. K. Heng, Philip A Wescombe, Nurul S Hajiishak, Alaina Kalyan, Andrew Y C Wong, Marija Lovric, Joanna M Bridson, Julia Artamonova, Joann L Stanton, Jeremy P Burton
    Abstract:

    Streptococcus salivarius is a Gram-positive bacterial commensal and pioneer colonizer of the human oral cavity. Many strains produce ribosomally synthesized proteinaceous antibiotics (bacteriocins), and some strains have been developed for use as oral probiotics. Here, we present the draft genome sequence of the bacteriocin-producing oral probiotic S. salivarius strain M18.

  • Something Old and Something New: An Update on the Amazing Repertoire of Bacteriocins Produced by Streptococcus salivarius
    Probiotics and Antimicrobial Proteins, 2010
    Co-Authors: Philip A Wescombe, Nicholas C. K. Heng, Jeremy P Burton, John R Tagg
    Abstract:

    Streptococcus salivarius has an exclusive and intimate association with humans. We are its sole natural host, and its contribution to the relationship appears overwhelmingly benevolent. Beautifully adapted to its preferred habitat, the human tongue, it only rarely ventures far from this location in the healthy host and indeed appears ill-equipped to become invasive due to a scarcity of virulence attributes. We consider that its strategically advantageous lingual location and numerical predominance allow S. salivarius to carry out a population surveillance and modulation role within the oral microbiota. Some strains are armed with complex arrays of targeted antibiotic weaponry, much of which belongs to the lantibiotic class of bacteriocins and a key to their ability to assemble and utilize this armament is their possession of transmissible multi-bacteriocin-encoding megaplasmid DNA. This review traces the origins of research into S. salivarius bacteriocins and bacteriocin-like inhibitory substances, showcases some of the inhibitory activities that we currently have knowledge of, and speculates about potential directions for ongoing investigation and probiotic application of this previously under-rated human commensal.

  • streptococcal bacteriocins and the case for Streptococcus salivarius as model oral probiotics
    Future Microbiology, 2009
    Co-Authors: Philip A Wescombe, Nicholas C. K. Heng, Jeremy P Burton, Chris N Chilcott, John R Tagg
    Abstract:

    Members of the Gram-positive bacterial genus Streptococcus are a diverse collection of species inhabiting many body sites and range from benign, nonpathogenic species to those causing life-threatening infections. The streptococci are also prolific producers of bacteriocins, which are ribosomally synthesized proteinaceous antibiotics that kill or inhibit species closely related to the producer bacterium. With the emergence of bacterial resistance to conventional antibiotics, there is an impetus to discover, and implement, new and preferably 'natural' antibiotics to treat or prevent bacterial infections, a niche that bacterial interference therapy mediated by bacteriocins could easily fill. This review focuses on describing the diversity of bacteriocins produced by streptococci and also puts forth a case for Streptococcus salivarius, a nonpathogenic and numerically predominant oral species, as an ideal candidate for development as the model probiotic for the oral cavity. S. salivarius is a safe species that not only produces broad-spectrum bacteriocins but harbors bacteriocin-encoding (and bacteriocin-inducing) transmissible DNA entities (megaplasmids).

  • preliminary investigations of the colonisation of upper respiratory tract tissues of infants using a paediatric formulation of the oral probiotic Streptococcus salivarius k12
    European Journal of Clinical Microbiology & Infectious Diseases, 2008
    Co-Authors: D A Power, Jeremy P Burton, C N Chilcott, Patrick J D Dawes, John R Tagg
    Abstract:

    A powder preparation of the oral probiotic Streptococcus salivarius K12 has been given to 19 young otitis media-prone children following a 3-day course of amoxicillin administered as a preliminary to ventilation tube placement. In two subjects, the use of strain K12 appeared to effect the expansion of an indigenous population of inhibitory S. salivarius. In other children, strain K12 colonisation extended beyond the oral cavity to also include the nasopharynx or adenoid tissue. The relatively low proportion (33%) of subjects that colonised was attributed to failure of the amoxicillin pre-treatment to sufficiently reduce the indigenous S. salivarius populations prior to dosing with strain K12 powder.

Philip A Wescombe - One of the best experts on this subject based on the ideXlab platform.

  • investigation of Streptococcus salivarius mediated inhibition of pneumococcal adherence to pharyngeal epithelial cells
    BMC Microbiology, 2016
    Co-Authors: John R Tagg, Philip A Wescombe, John D F Hale, Jayne Manning, Eileen M Dunne, Kim E Mulholland, Roy M Robinsbrowne
    Abstract:

    Background Pneumococcal adherence to the nasopharyngeal epithelium is a critical step in colonisation and disease. The probiotic bacterium, Streptococcus salivarius, can inhibit pneumococcal adherence to epithelial cells in vitro. We investigated the mechanism(s) of inhibition using a human pharyngeal epithelial cell line (Detroit 562) following pre-administration of two different strains of S. salivarius.

  • Streptococcus salivarius k12 limits group b Streptococcus vaginal colonization
    Infection and Immunity, 2015
    Co-Authors: Kathryn A Patras, John R Tagg, Philip A Wescombe, John D F Hale, Berenice Rosler, Kelly S Doran
    Abstract:

    Streptococcus agalactiae (group B Streptococcus [GBS]) colonizes the rectovaginal tract in 20% to 30% of women and during pregnancy can be transmitted to the newborn, causing severe invasive disease. Current routine screening and antibiotic prophylaxis have fallen short of complete prevention of GBS transmission, and GBS remains a leading cause of neonatal infection. We have investigated the ability of Streptococcus salivarius, a predominant member of the native human oral microbiota, to control GBS colonization. Comparison of the antibacterial activities of multiple S. salivarius strains by use of a deferred-antagonism test showed that S. salivarius strain K12 exhibited the broadest spectrum of activity against GBS. K12 effectively inhibited all GBS strains tested, including disease-implicated isolates from newborns and colonizing isolates from the vaginal tract of pregnant women. Inhibition was dependent on the presence of megaplasmid pSsal-K12, which encodes the bacteriocins salivaricin A and salivaricin B; however, in coculture experiments, GBS growth was impeded by K12 independently of the megaplasmid. We also demonstrated that K12 adheres to and invades human vaginal epithelial cells at levels comparable to GBS. Inhibitory activity of K12 was examined in vivo using a mouse model of GBS vaginal colonization. Mice colonized with GBS were treated vaginally with K12. K12 administration significantly reduced GBS vaginal colonization in comparison to nontreated controls, and this effect was partially dependent on the K12 megaplasmid. Our results suggest that K12 may have potential as a preventative therapy to control GBS vaginal colonization and thereby prevent its transmission to the neonate during pregnancy.

  • developing oral probiotics from Streptococcus salivarius
    Future Microbiology, 2012
    Co-Authors: Philip A Wescombe, Nicholas C. K. Heng, John D F Hale, John R Tagg
    Abstract:

    Considerable human illness can be linked to the development of oral microbiota disequilibria. The predominant oral cavity commensal, Streptococcus salivarius has emerged as an important source of safe and efficacious probiotics, capable of fostering more balanced, health-associated oral microbiota. Strain K12, the prototype S. salivarius probiotic, originally introduced to counter Streptococcus pyogenes infections, now has an expanded repertoire of health-promoting applications. K12 and several more recently proposed S. salivarius probiotics are now being applied to control diverse bacterial consortia infections including otitis media, halitosis and dental caries. Other potential applications include upregulation of immunological defenses against respiratory viral infections and treatment of oral candidosis. An overview of the key steps required for probiotic development is also presented.

  • salivaricin g32 a homolog of the prototype Streptococcus pyogenes nisin like lantibiotic sa ff22 produced by the commensal species Streptococcus salivarius
    International Journal of Microbiology, 2012
    Co-Authors: Philip A Wescombe, Jeremy P Burton, Kristin H Dyet, Karen P Dierksen, Daniel A Power, Ralph W Jack, Megan A Inglis, Anna L Wescombe, John R Tagg
    Abstract:

    Salivaricin G32, a 2667 Da novel member of the SA-FF22 cluster of lantibiotics, has been purified and characterized from Streptococcus salivarius strain G32. The inhibitory peptide differs from the Streptococcus pyogenes—produced SA-FF22 in the absence of lysine in position 2. The salivaricin G32 locus was widely distributed in BLIS-producing S. salivarius, with 6 (23%) of 26 strains PCR-positive for the structural gene, slnA. As for most other lantibiotics produced by S. salivarius, the salivaricin G32 locus can be megaplasmid encoded. Another member of the SA-FF22 family was detected in two Streptococcus dysgalactiae of bovine origin, an observation supportive of widespread distribution of this lantibiotic within the genus Streptococcus. Since the inhibitory spectrum of salivaricin G32 includes Streptococcus pyogenes, its production by S. salivarius, either as a member of the normal oral microflora or as a commercial probiotic, could serve to enhance protection of the human host against S. pyogenes infection.

  • genome sequence of the bacteriocin producing oral probiotic Streptococcus salivarius strain m18
    Journal of Bacteriology, 2011
    Co-Authors: Nicholas C. K. Heng, Philip A Wescombe, Nurul S Hajiishak, Alaina Kalyan, Andrew Y C Wong, Marija Lovric, Joanna M Bridson, Julia Artamonova, Joann L Stanton, Jeremy P Burton
    Abstract:

    Streptococcus salivarius is a Gram-positive bacterial commensal and pioneer colonizer of the human oral cavity. Many strains produce ribosomally synthesized proteinaceous antibiotics (bacteriocins), and some strains have been developed for use as oral probiotics. Here, we present the draft genome sequence of the bacteriocin-producing oral probiotic S. salivarius strain M18.

Christine Delorme - One of the best experts on this subject based on the ideXlab platform.

  • Identification of New Factors Modulating Adhesion Abilities of the Pioneer Commensal Bacterium Streptococcus salivarius
    Frontiers in Microbiology, 2018
    Co-Authors: Benoit Couvigny, Christine Delorme, Nicolas Pons, Pierre Renault, Annelaure Abraham, Saulius Kulakauskas, Benoit Quinquis, Thierry Meylheuc, Romain Briandet, Nicolas Lapaque
    Abstract:

    Biofilm formation is crucial for bacterial community development and host colonization by Streptococcus salivarius, a pioneer colonizer and commensal bacterium of the human gastrointestinal tract. This ability to form biofilms depends on bacterial adhesion to host surfaces, and on the intercellular aggregation contributing to biofilm cohesiveness. Many S. salivarius isolates auto-aggregate, an adhesion process mediated by cell surface proteins. To gain an insight into the genetic factors of S. salivarius that dictate host adhesion and biofilm formation, we developed a screening method, based on the differential sedimentation of bacteria in semi-liquid conditions according to their auto-aggregation capacity, which allowed us to identify twelve mutations affecting this auto-aggregation phenotype. Mutations targeted genes encoding (i) extracellular components, including the CshA surface-exposed protein, the extracellular BglB glucan-binding protein, the GtfE, GtfG and GtfH glycosyltransferases and enzymes responsible for synthesis of cell wall polysaccharides (CwpB, CwpK), (ii) proteins responsible for the extracellular localization of proteins, such as structural components of the accessory SecA2Y2 system (Asp1, Asp2, SecA2) and the SrtA sortase, and (iii) the LiaR transcriptional response regulator. These mutations also influenced biofilm architecture, revealing that similar cell-to-cell interactions govern assembly of auto-aggregates and biofilm formation. We found that BglB, CshA, GtfH and LiaR were specifically associated with bacterial auto-aggregation, whereas Asp1, Asp2, CwpB, CwpK, GtfE, GtfG, SecA2 and SrtA also contributed to adhesion to host cells and host-derived components, or to interactions with the human pathogen Fusobacterium nucleatum. Our study demonstrates that our screening method could also be used to identify genes implicated in the bacterial interactions of pathogens or probiotics, for which aggregation is either a virulence trait or an advantageous feature, respectively.

  • genomics of Streptococcus salivarius a major human commensal
    Infection Genetics and Evolution, 2015
    Co-Authors: Christine Delorme, Eric Guédon, Pierre Renault, Annelaure Abraham
    Abstract:

    The salivarius group of streptococci is of particular importance for humans. This group consists of three genetically similar species, Streptococcus salivarius, Streptococcus vestibularis and Streptococcus thermophilus. S. salivarius and S. vestibularis are commensal organisms that may occasionally cause opportunistic infections in humans, whereas S. thermophilus is a food bacterium widely used in dairy production. We developed Multilocus sequence typing (MLST) and comparative genomic analysis to confirm the clear separation of these three species. These analyses also identified a subgroup of four strains, with a core genome diverging by about 10%, in terms of its nucleotide sequence, from that of S. salivarius sensu stricto. S. thermophilus species displays a low level of nucleotide variability, due to its recent emergence with the development of agriculture. By contrast, nucleotide variability is high in the other two species of the salivarius group, reflecting their long-standing association with humans. The species of the salivarius group have genome sizes ranging from the smallest (∼1.7Mb for S. thermophilus) to the largest (∼2.3Mb for S. salivarius) among streptococci, reflecting genome reduction linked to a narrow, nutritionally rich environment for S. thermophilus, and natural, more competitive niches for the other two species. Analyses of genomic content have indicated that the core genes of S. salivarius account for about two thirds of the genome, indicating considerable variability of gene content and differences in potential adaptive features. Furthermore, we showed that the genome of this species is exceptionally rich in genes encoding surface factors, glycosyltransferases and response regulators. Evidence of widespread genetic exchanges was obtained, probably involving a natural competence system and the presence of diverse mobile elements. However, although the S. salivarius strains studied were isolated from several human body-related sites (all levels of the digestive tract, skin, breast milk, and body fluids) and included clinical strains, no genetic or genomic niche-specific features could be identified to discriminate specific group.

  • Commensal [i]Streptococcus salivarius[/i] modulates PPARγ transcriptional activity in human intestinal epithelial cells
    PLoS ONE, 2015
    Co-Authors: Benoit Couvigny, Christine Delorme, Eric Guédon, Ghalia Kaci, Joel Dore, Pierre Renault, Herve Blottiere, Tomas De Wouters, Elsa Jacouton, Nicolas Lapaque
    Abstract:

    The impact of commensal bacteria in eukaryotic transcriptional regulation has increasingly been demonstrated over the last decades. A multitude of studies have shown direct effects of commensal bacteria from local transcriptional activity to systemic impact. The commensal bacterium Streptococcus salivarius is one of the early bacteria colonizing the oral and gut mucosal surfaces. It has been shown to down-regulate nuclear transcription factor (NF-кB) in human intestinal cells, a central regulator of the host mucosal immune system response to the microbiota. In order to evaluate its impact on a further important transcription factor shown to link metabolism and inflammation in the intestine, namely PPARγ (peroxisome proliferator-activated receptor), we used human intestinal epithelial cell-lines engineered to monitor PPARγ transcriptional activity in response to a wide range of S. salivarius strains. We demonstrated that different strains from this bacterial group share the property to inhibit PPARγ activation independently of the ligand used. First attempts to identify the nature of the active compounds showed that it is a low-molecular-weight, DNase-, proteases- and heat-resistant metabolite secreted by S. salivarius strains. Among PPARγ-targeted metabolic genes, I-FABP and Angptl4 expression levels were dramatically reduced in intestinal epithelial cells exposed to S. salivarius supernatant. Both gene products modulate lipid accumulation in cells and down-regulating their expression might consequently affect host health. Our study shows that species belonging to the salivarius group of streptococci impact both host inflammatory and metabolic regulation suggesting a possible role in the host homeostasis and health.

  • Anti-inflammatory properties of [i]Streptococcus salivarius[/i], a commensal bacterium of the oral cavity and digestive tract
    Applied and Environmental Microbiology, 2014
    Co-Authors: Ghalia Kaci, Joel Dore, Pierre Renault, Denise Goudercourt, Véronique Dennin, Bruno Pot, Stanislav Ehrlich, Herve Blottiere, Catherine Daniel, Christine Delorme
    Abstract:

    Streptococcus salivarius is one of the first colonizers of the human oral cavity and gut after birth and therefore may contribute to the establishment of immune homeostasis and regulation of host inflammatory responses. The anti-inflammatory potential of S. salivarius was first evaluated in vitro on human intestinal epithelial cells and human peripheral blood mononuclear cells. We show that live S. salivarius strains inhibited in vitro the activation of the NF-κB pathway on intestinal epithelial cells. We also demonstrate that the live S. salivarius JIM8772 strain significantly inhibited inflammation in severe and moderate colitis mouse models. These in vitro and in vivo anti-inflammatory properties were not found with heat-killed S. salivarius, suggesting a protective response exclusively with metabolically active bacteria.

  • complete genome sequence of the commensal Streptococcus salivarius strain jim8777
    Journal of Bacteriology, 2011
    Co-Authors: Christine Delorme, Eric Guédon, Nicolas Pons, Corinne Cruaud, Arnaud Couloux, Valentin Loux, Celine Gautier
    Abstract:

    ABSTRACT The commensal bacterium Streptococcus salivarius is a prevalent species of the human oropharyngeal tract with an important role in oral ecology. Here, we report the complete 2.2-Mb genome sequence and annotation of strain JIM8777, which was recently isolated from the oral cavity of a healthy, dentate infant.

Francesco Di Pierro - One of the best experts on this subject based on the ideXlab platform.