Walid Mottawea

University of Ottawa · School of Nutrition Sciences

Intestinal microbial dysbiosis is associated with Crohn's disease (CD). However, the mechanisms leading to the chronic mucosal inflammation that characterizes this disease remain unclear. In this report, we use systems-level approaches to study the interactions between the gut microbiota and host in new-onset paediatric patients to evaluate causali...

Extracellular vesicles have emerged as key players in cellular communication, influencing various physiological processes and pathophysiological progression, including digestion, immune response, and tissue repairs. Recently, a class of EVs derived from microbial communities has gained significant attention due to their pivotal role in intercellula...

Campylobacter jejuni (C. jejuni) is one of the most common causes of foodborne infections worldwide and a major contributor to diarrheal diseases. This study aimed to explore the ability of commensal gut bacteria to control C. jejuni infection. Bacterial strains from the intestinal mucosa of broilers were screened in vitro against C. jejuni ATCC BA...

Dietary prebiotic fibers play an important role in modulating gut microbiota by enhancing the abundance of beneficial microorganisms and their bioactive metabolites. However, dietary fibers are a structurally heterogeneous class of polysaccharides, varying in molar mass, branching patterns, and monosaccharide composition, which could influence thei...

In this study, we aimed to develop a protective probiotic coculture to inhibit the growth of Salmonella enterica serovar Typhimurium in the simulated chicken gut environment. Bacterial strains were isolated from the digestive mucosa of broilers and screened in vitro against Salmonella Typhimurium ATCC 14028. A biocompatibility coculture test was pe...

Arabinoxylan (AX) is an essential component of dietary fiber with potential prebiotic properties. However, owing to its complex structure, fermentation of AX by gut microbes is structure dependent. In this study, we evaluated the effect of bioengineered wheat AX on the metabolism and composition of gut microbiota using an in vitro fermentation mode...

Growing evidence indicates that non-antibiotic therapeutics significantly impact human health by modulating gut microbiome composition and metabolism. In this study, we investigated the impact of two psychotropic drugs, aripiprazole and (S)-citalopram, on gut microbiome composition and its metabolic activity, as well as the potential of probiotics...

We announce the draft genome sequences of 12 Bacteroides, 4 Phocaeicola, and 2 Parabacteroides strains, among which was a newly isolated species, Bacteroidaceae bacterium UO.H1004. These isolates produce health-benefiting short-chain fatty acids (SCFAs) and the neurotransmitter γ-aminobutyric acid (GABA) in various concentrations.

Salmonella spp is one of the leading causes of bacterial foodborne illnesses worldwide resulting in acute gastroenteritis. The current study aimed to explore the inhibitory activity of two newly isolated probiotic candidates Lactiplantibacillus plantarum MYSAS1 and Enterococcus faecium MYSAS4 from fermented black cherry fruit, against Salmonella en...

Over decades, probiotic research has focused on their benefits to gut health. Recently, the gut microbiota has been proven to share bidirectional connections with the brain through the gut–brain axis. Therefore, the manipulation of this axis via probiotics has garnered interest. We have recently isolated and characterized in vitro probiotic candida...

This study aims to develop a new, simple, and efficient method for estimating the total antioxidant capacity of lactic acid bacteria-free supernatant. The bioassay is based on diffusion and reduction of permanganate in agar medium under acidic conditions where the Mn7+ ions are quantitatively oxidized to Mn2+ and shift from an intense purple color...

This study aims to develop a new, simple, and efficient method for estimating the total antioxidant capacity of lactic acid bacteria-cell free supernatant. The bioassay is based on diffusion and reduction of permanganate in agar medium under acidic conditions where the Mn7+ ions are quantitatively oxidized to Mn2+ and shift from an intense purple c...

Over the past decade, gut microbiota dysbiosis has been linked to many health disorders; however, the detailed mechanism of this correlation remains unclear. Gut microbiota can communicate with the host through immunological or metabolic signalling. Recently, microbiota-released extracellular vesicles (MEVs) have emerged as significant mediators in...

Inflammatory bowel diseases (IBD) are chronic medical disorders characterized by recurrent gastrointestinal inflammation. While the etiology of IBD is still unknown, the pathogenesis of the disease results from perturbations in both gut microbiota and the host immune system. Gut microbiota dysbiosis in IBD is characterized by depleted diversity, re...

Mutations in susceptibility alleles correlate with gut-inflammatory diseases, such as Crohn’s disease; however, this does not often impact the disease progression indicating the existence of compensatory genes. We show that a reduction in Foxo3a expression in IL-10-deficient mice results in a spontaneous and aggressive Crohn’s- like disease with 10...

The use of probiotics and antifungal capabilities of the lactic acid bacteria (LAB) isolated from different niches is a strategy to prepare functional cultures and biopreservatives for food/feed industries. In the present study, LAB strains isolated from an Indian traditional fermented food, Pozha, were evaluated for their probiotic properties and...

The use of probiotics and antifungal capabilities of the lactic acid bacteria (LAB) isolated from different niches is a strategy to prepare functional cultures and biopreservatives for food/feed industries. In the present study, LAB strains isolated from an Indian traditional fermented food, Pozha, were evaluated for their probiotic properties and...

The misuse of antibiotics in the livestock industry has played an important role in the spread of resistant superbugs with severe health implications for humans. With the recent ban on the use of antibiotics in poultry and poultry feed in Canada and the USA, poultry farmers will have to rely on the use of alternatives to antibiotics (such as feed a...

The poultry industry is the fastest-growing agricultural sector globally. With poultry meat being economical and in high demand, the end product’s safety is of importance. Globally, governments are coming together to ban the use of antibiotics as prophylaxis and for growth promotion in poultry. Salmonella and Clostridium perfringens are two leading...

The gut–liver-axis is a bidirectional coordination between the gut, including microbial residents, the gut microbiota, from one side and the liver on the other side. Any disturbance in this crosstalk may lead to a disease status that impacts the functionality of both the gut and the liver. A major cause of liver disorders is hepatitis C virus (HCV)...

Emerging evidence highlighted the essential role played by the microbiota-gut-brain axis in maintaining human homeostasis, including nutrition, immunity, and metabolism. Much recent work has linked the gut microbiota to many psychiatric and neurodegenerative disorders such as depression, schizophrenia, and Alzheimer's disease. Shared gut microbiota...

Gut microbiota dysbiosis has been linked to many heath disorders including hepatitis C virus (HCV) infection. However, profiles of the gut microbiota alterations in HCV are inconsistent in the literature and are affected by the treatment regimens. Using samples collected prior to treatment from newly diagnosed patients, we characterized the gut mic...

Over the past decade, there has been increasing evidence highlighting the implication of the gut microbiota in a variety of brain disorders such as depression, anxiety, and schizophrenia. Studies have shown that depression affects the stability of gut microbiota, but the impact of antidepressant treatments on microbiota structure and metabolism rem...

Behavior and mood disorders have been linked to gut microbiota dysbiosis through the "microbiota-gut-brain axis". Microbiota-targeting interventions are promising therapeutic modalities to restore or even maintain normal microbiome composition and activity in these disorders. Here, we test the impact of a commercial synbiotic formulation on gut mic...

Background: Alterations in gastrointestinal microbial communities have been linked to human disease. Most studies use fecal samples as a proxy for the intestinal microbiota; however, the fecal microbiome is not fully representative of the mucosa-associated microbiota at the site of disease. While mucosal biopsies can be used instead, they often co...

Commercial trends based of the emergence of plant-based functional foods lead to investigate the structure-function relationship of their main bioactive constituents and their interactions in the food matrix and throughout the gastro-intestinal tract. Among these bioactive constituents, dietary polysaccharides and polyphenols have shown to interact...

A considerable number of strains belonging to different species of Enterococcus are highly competitive due to their resistance to wide range of pH and temperature. Their competitiveness is also owed to their ability to produce bacteriocins recognized for their wide-range effectiveness on pathogenic and spoilage bacteria. Enterococcal bacteriocins h...

Non-typhoidal Salmonella is a leading cause of foodborne illness worldwide. Prompt and accurate identification of the sources of Salmonella responsible for disease outbreaks is crucial to minimize infections and eliminate ongoing sources of contamination. Current subtyping tools including single nucleotide polymorphism (SNP) typing may be inadequat...

Background Very-low-birth-weight (VLBW; born weighing <1500 g) infant feeding with mother's own milk (mother's milk) is associated with numerous beneficial health outcomes. Several interventions, including the prophylactic use of probiotics, are being adopted to promote a gastrointestinal microbiota favorable to the gut health of VLBW infants. An i...

The Salmonella Syst-OMICS consortium is sequencing 4,500 Salmonella genomes and building an analysis pipeline for the study of Salmonella genome evolution, antibiotic resistance and virulence genes. Metadata, including phenotypic as well as genomic data, for isolates of the collection are provided through the Salmonella Foodborne Syst-OMICS databas...

Listeria monocytogenes is the etiological agent for an often fatal foodborne illness known as listeriosis. Here, we present the complete genome sequences of 12 L. monocytogenes isolates representing the three most common serotypes of this pathogen (1/2a, 1/2b, and 4b), collected in Canada from different food products and environmental sources.

OTUs that differ significantly in abundance in at least one of the two pairwise comparisons performed (controls vs. CD or controls vs. UC; p values calculated using metagenomeSeq).

Taxa that differ significantly in control vs CD or UC patients by LEfSe analysis.

Comparison between differentially abundant bacteria using V4/V6 regions and Illumina/Ion Torrent sequencing platforms.

Relative abundances and error rates for pure cultures sequenced using the 16S-V6-rDNA protocol.

OTUs that differ significantly in abundance as a function of inflammation severity in CD patients in at least one of the three pairwise comparisons performed (mild vs. moderate; mild vs. severe; and moderate vs. severe).

Supplementary Figures 1-16, Supplementary Tables 1-5 and Supplementary References

Objective: Accurate differentiation between Crohn's disease (CD) and UC is important to ensure early and appropriate therapeutic intervention. We sought to identify proteins that enable differentiation between CD and UC in children with new onset IBD. Design: Mucosal biopsies were obtained from children undergoing baseline diagnostic endoscopy p...

Cathelicidin antimicrobial peptide (CAMP) is a naturally-occurring secreted peptide expressed in several organs with pleiotropic roles in immunomodulation, wound healing and cell growth. We previously demonstrated that gut Camp expression is up-regulated when type 1 diabetes (T1D)-prone rats are protected from diabetes development. Unexpectedly, we...

There is provided methods and compositions to diagnose, classify and treat inflammatory bowel disease including ulcerative colitis and Crohn's disease by measuring the levels of certain bacterial taxa and proteins collected from the gut.

Type 2 diabetes, hepatic steatosis, and gut dysbiosis are pathophysiological consequences of obesity. Sirtuin (SIRT)-1 is a protein deacetylase implicated in the regulation of metabolic activity. We set out to determine whether the catalytic activity of SIRT1 plays a role in the development of metabolic syndrome, hepatic steatosis, and the distribu...

This study aims to investigate moving bed biofilm reactor (MBBR) nitrification rates, nitrifying biofilm morphology, biomass viability as well as bacterial community shifts during long-term exposure to 1 °C. Long-term exposure to 1 °C is the key operational condition for potential ammonia removal upgrade units to numerous northern region treatment...

Pseudomonas aeruginosa is an opportunistic human pathogen and one of the leading causes of nosocomial infections worldwide. The difficulty in treatment of pseudomonas infections arises from being multidrug resistant (MDR) and exhibits resistance to most antimicrobial agents due to the expression of different mechanisms overcoming their effects. Of...

Listeriosis is a food-borne disease caused by the opportunistic pathogen Listeria monocytogenes. Internalization of Listeria into non phagocytic cells is the crucial step in the pathogenesis of listeriosis. This process is mediated by a group of 25 surface and secretory proteins called internalins. The majority of internalins share an N-terminal su...