Novel bacterial proteolytic and metabolic activity associated with dental erosion-induced oral dysbiosis

Abstract Background Dental erosion is a disease of the oral cavity where acids cause a loss of tooth enamel and is defined as having no bacterial involvement. The tooth surface is protected from acid attack by salivary proteins that make up the acquired enamel pellicle (AEP). Bacteria have been shown to readily degrade salivary proteins, and some of which are present in the AEP. This study aimed to explore the role of bacteria in dental erosion using a multi-omics approach by comparing saliva collected from participants with dental erosion and healthy controls. Results Salivary proteomics was assessed by liquid-chromatography mass spectrometry (LC–MS) and demonstrated two altered AEP proteins in erosion, prolactin inducible protein (PIP), and zinc-alpha-2 glycoprotein (ZAG). Immunoblotting further suggested that degradation of PIP and ZAG is associated with erosion. Salivary microbiome analysis was performed by sequencing the bacterial 16S rRNA gene (V1-V2 region, Illumina) and showed that participants with dental erosion had a significantly (p < 0.05) less diverse microbiome than healthy controls (observed and Shannon diversity). Sequencing of bacterial mRNA for gene expression (Illumina sequencing) demonstrated that genes over-expressed in saliva from erosion participants included H + proton transporter genes, and three protease genes (msrAB, vanY, and ppdC). Salivary metabolomics was assessed using nuclear magnetic resonance spectrometry (NMR). Metabolite concentrations correlated with gene expression, demonstrating that the dental erosion group had strong correlations between metabolites associated with protein degradation and amino acid fermentation. Conclusions We conclude that microbial proteolysis of salivary proteins found in the protective acquired enamel pellicle strongly correlates with dental erosion, and we propose four novel microbial genes implicated in this process. Video Abstrac

Comprehensive identification of Vibrio vulnificus genes required for growth in human serum

Vibrio vulnificus can be a highly invasive pathogen capable of spreading from an infection site to the bloodstream, causing sepsis and death. To survive and proliferate in blood, the pathogen requires mechanisms to overcome the innate immune defenses and metabolic limitations of this host niche. We created a high-density transposon mutant library in YJ016, a strain representative of the most virulent V. vulnificus lineage (or phylogroup) and used transposon insertion sequencing (TIS) screens to identify loci that enable the pathogen to survive and proliferate in human serum. Initially, genes underrepresented for insertions were used to estimate the V. vulnificus essential gene set; comparisons of these genes with similar TIS-based classification of underrepresented genes in other vibrios enabled the compilation of a common Vibrio essential gene set. Analysis of the relative abundance of insertion mutants in the library after exposure to serum suggested that genes involved in capsule biogenesis are critical for YJ016 complement resistance. Notably, homologues of two genes required for YJ016 serum-resistance and capsule biogenesis were not previously linked to capsule biogenesis and are largely absent from other V. vulnificus strains. The relative abundance of mutants after exposure to heat inactivated serum was compared with the findings from the serum screen. These comparisons suggest that in both conditions the pathogen relies on its Na+ transporting NADH-ubiquinone reductase (NQR) complex and type II secretion system to survive/proliferate within the metabolic constraints of serum. Collectively, our findings reveal the potency of comparative TIS screens to provide knowledge of how a pathogen overcomes the diverse limitations to growth imposed by serum

Nutritionally-mediated changes of butyrate feed supplementation in the composition of gut microbiota, immune response and protection against photobacteriosis in gilthead seabream (Sparus aurata)

Comunicación presentada en el Aquaculture Europe 2014, celebrado en Donostia-San Sebastián, España, del 14 al 17 de octubre de 2014Aquaculture is the food production sector growing fastest in last years, but infectious diseases are an important constraint for its advance. The inclusion of immunostimulants in fish feeds (functional diets) is one of the main strategies to achieve sustainable aquatic cultures. Since butyric acid and butyrate may exert a positive effect on fish gut health, they appear as promising additives in fish feeds (Gao et al., 2011). The present study aimed to analyze the effects of sodium butyrate feed supplementation upon the composition of the intestinal microbiota (IM) and the innate immune response of gilthead sea bream (Sparus aurata), as well as the protection against photobacteriosis, a disease caused by the bacterium Photobacterium damselae subsp. piscicida (Pdp) (Toranzo et al., 2005).This research was partially funded by ARRAINA EU Project (KBBE-2011-288925) and REVIDPAQUA project (ISIC/2012/003) from the Generalitat Valenciana.Peer Reviewe

Draft genome sequences of Vibrio vulnificus strains recovered from moribund tilapia

Potentially zoonotic Vibrio vulnificus strains were isolated from vibriosis outbreaks occurring on eastern Mediterranean tilapia farms between 2016 and 2019. In this work, the draft genome sequences of three representative isolates are presented.This work has been financed by grants AGL2017-87723-P (Ministerio de Ciencia, Innovación y Universidades [Spain] and FEDER funds) and AICO/2020/076 (Generalitat Valenciana [Spain]). Héctor Carmona-Salido has been financed by the FPI grant PRE2018- 083819 (Ministerio de Ciencia, Inovación y Universidades [Spain]).Peer reviewe

The widespread presence of a family of fish virulence plasmids in Vibrio vulnificus stresses its relevance as a zoonotic pathogen linked to fish farms

Vibrio vulnificus is a pathogen of public health concern that causes either primary septicemia after ingestion of raw shellfish or secondary septicemia after wound exposure to seawater. In consequence, shellfish and seawater are considered its main reservoirs. However, there is one aspect of its biology that is systematically overlooked: its association with fish in its natural environment. This association led in 1975 to the emergence of a zoonotic clade within phylogenetic lineage 2 following successive outbreaks of vibriosis in farmed eels. Although this clade is now worldwide distributed, no new zoonotic clades were subsequently reported. In this work, we have performed phylogenetic, genomic and functional studies to show that other zoonotic clades are in fact present in 4 of the 5 lineages of the species. Further, we associate these clades, most of them previously but incompletely described, with the acquisition of a family of fish virulence plasmids containing genes essential for resistance to the immune system of certain teleosts of interest in aquaculture. Consequently, our results provide several pieces of evidence about the importance of this species as a zoonotic agent linked to fish farms, as well as on the relevance of these artificial environments acting as drivers that accelerate the evolution of the species.This work has been financed by grants AGL2017-87723-P and BFU2017-89594-funded by Ministerio de Ciencia, Innovacion y Universidades 10.13039/501100011033 and by “ERDF A way of making Europe,” grant PID2020-120619RB-I00 funded by Ministerio de Ciencia e Innovación (MICIN/AEI) (DOI ID: 10.13039/501100011033) and grant AICO/2020/076 funded by the “Generalitat Valenciana”. Carmona-Salido, H. has been financed by grant PRE-2018-083819 funded by Ministerio de Ciencia e Innovación (MICIN/AEI) (DOI ID: 10.13039/501100011033). Sequencing at FISABIO was made possible through an “Action co-financed by the European Union through the Operational Program of European Regional Development Fund (ERDF) of Valencia Region (Spain) 2014-2020”.Peer reviewe

Comprehensive identification of <i>Vibrio vulnificus</i> genes required for growth in human serum

<p><i>Vibrio vulnificus</i> can be a highly invasive pathogen capable of spreading from an infection site to the bloodstream, causing sepsis and death. To survive and proliferate in blood, the pathogen requires mechanisms to overcome the innate immune defenses and metabolic limitations of this host niche. We created a high-density transposon mutant library in YJ016, a strain representative of the most virulent <i>V. vulnificus</i> lineage (or phylogroup) and used transposon insertion sequencing (TIS) screens to identify loci that enable the pathogen to survive and proliferate in human serum. Initially, genes underrepresented for insertions were used to estimate the <i>V. vulnificus</i> essential gene set; comparisons of these genes with similar TIS-based classification of underrepresented genes in other vibrios enabled the compilation of a common <i>Vibrio</i> essential gene set. Analysis of the relative abundance of insertion mutants in the library after exposure to serum suggested that genes involved in capsule biogenesis are critical for YJ016 complement resistance. Notably, homologues of two genes required for YJ016 serum-resistance and capsule biogenesis were not previously linked to capsule biogenesis and are largely absent from other <i>V. vulnificus</i> strains. The relative abundance of mutants after exposure to heat inactivated serum was compared with the findings from the serum screen. These comparisons suggest that in both conditions the pathogen relies on its Na⁺ transporting NADH-ubiquinone reductase (NQR) complex and type II secretion system to survive/proliferate within the metabolic constraints of serum. Collectively, our findings reveal the potency of comparative TIS screens to provide knowledge of how a pathogen overcomes the diverse limitations to growth imposed by serum.</p