The Canine Gut Health: The Impact of a New Feed Supplement on Microbiota Composition.

This study aimed to determine the impact of a novel formulation of a supplement composed of the natural ingredients, bromelain, quercetin, and Lentinula edodes, on the gut microbiota of healthy adult dogs. Adult healthy female dogs were administered either a placebo (CTR, n = 15) or the supplement (TRT, n = 15) over 28 days. Stool samples were collected for 16S rRNA sequencing before supplement administration (T0), at completion of supplement administration (T28), and one week after the end of supplement administration (T35) to characterize changes in the gut microbial communities. QIIME was used to determine both alpha- and beta-diversity, and ANCOM-BC was used to identify differences in taxonomic abundances before and after supplementation. We found a significant decrease in overall diversity in the CTR group but no significant differences in overall diversity in the TRT group over time. Furthermore, we found differences in the abundance of several taxa in both the CTR and TRT groups, but differences in the abundance of beneficial bacteria were more pronounced in the TRT group. Specifically, we found increases in the abundance of sequences belonging to the genera Bifidobacterium, Lactobacillus, and Pediococcus at T28 in the TRT group with significant increases in Bifidobacterium and Lactobacillus persisting at T35 when compared to T0. Importantly, members of these genera are considered important for their anti-inflammatory properties, vital for fostering a balanced and robust gut microbiota in dogs. The results of our study show the potential of our supplement to selectively enhance specific beneficial bacterial taxa, offering a targeted approach to modulating the gut microbiome without causing disruptions to the overall equilibrium.

Neighborhood socioeconomic status is associated with low diversity gut microbiomes and multi-drug resistant microorganism colonization.

Social disparities continue to limit universal access to health care, directly impacting both lifespan and quality of life. Concomitantly, the gut microbiome has been associated with downstream health outcomes including the global rise in antibiotic resistance. However, limited evidence exists examining socioeconomic status (SES) associations with gut microbiome composition. To address this, we collected information on the community-level SES, gut microbiota, and other individual cofactors including colonization by multidrug-resistant organisms (MDROs) in an adult cohort from Wisconsin, USA. We found an association between SES and microbial composition that is mediated by food insecurity. Additionally, we observed a higher prevalence of MDROs isolated from individuals with low diversity microbiomes and low neighborhood SES. Our integrated population-based study considers how the interplay of several social and economic factors combine to influence gut microbial composition while providing a framework for developing future interventions to help mitigate the SES health gap.

The Microbiome and Mental Health Across the Lifespan.

INTRODUCTION: The combined genetic material of the microorganisms in the human body, known as the microbiome, is being increasingly recognized as a major determinant of human health and disease. Although located predominantly on mucosal surfaces, these microorganisms have profound effects on brain functioning through the gut-brain axis. METHOD: The content of the chapter is based on a study group session at the annual meeting of the American College of Neuropsychopharmacology (ACNP). The objective was to discuss the emerging relationship between the human microbiome and mental health as relevant to ACNP's interests in developing and evaluating novel neuropsychiatric treatment strategies. The focus is on specific brain disorders, such as schizophrenia, substance use, and Alzheimer's disease, as well as on broader clinical issues such as suicidality, loneliness and wisdom in old age, and longevity. RESULTS: Studies of schizophrenia indicate that the microbiome of individuals with this disorder differs from that of non-psychiatric comparison groups in terms of diversity and composition. Differences are also found in microbial metabolic pathways. An early study in substance use disorders found that individuals with this disorder have lower levels of beta diversity in their oral microbiome than a comparison group. This measure, along with others, was used to distinguish individuals with substance use disorders from controls. In terms of suicidality, there is preliminary evidence that persons who have made a suicide attempt differ from psychiatric and non-psychiatric comparison groups in measures of beta diversity. Exploratory studies in Alzheimer's disease indicate that gut microbes may contribute to disease pathogenesis by regulating innate immunity and neuroinflammation and thus influencing brain function. In another study looking at the microbiome in older adults, positive associations were found between wisdom and alpha diversity and negative associations with subjective loneliness. In other studies of older adults, here with a focus on longevity, individuals with healthy aging and unusually long lives had an abundance of specific microorganisms which distinguished them from other individuals. DISCUSSION: Future studies would benefit from standardizing methods of sample collection, processing, and analysis. There is also a need for the standardized collection of relevant demographic and clinical data, including diet, medications, cigarette smoking, and other potentially confounding factors. While still in its infancy, research to date indicates a role for the microbiome in mental health disorders and conditions. Interventions are available which can modulate the microbiome and lead to clinical improvements. These include microbiome-altering medications as well as probiotic microorganisms capable of modulating the inflammation in the brain through the gut-brain axis. This research holds great promise in terms of developing new methods for the prevention and treatment of a range of human brain disorders.

Genotyping and differential bacterial inhibition of Batrachochytrium dendrobatidis in threatened amphibians in Costa Rica.

Amphibians have declined around the world in recent years, in parallel with the emergence of an epidermal disease called chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). This disease has been associated with mass mortality in amphibians worldwide, including in Costa Rica, and Bd is considered an important contributor to the disappearance of this group of vertebrates. While many species are susceptible to the disease, others show tolerance and manage to survive infection with the pathogen. We evaluated the pathogen Bd circulating in Costa Rica and the capacity of amphibian skin bacteria to inhibit the growth of the pathogen in vitro. We isolated and characterized - genetically and morphologically - several Bd isolates from areas with declining populations of amphibians. We determined that the circulating chytrid fungus in Costa Rica belongs to the virulent strain Bd-GPL-2, which has been related to massive amphibian deaths worldwide; however, the isolates obtained showed genetic and morphological variation. Furthermore, we isolated epidermal bacteria from 12 amphibian species of surviving populations, some in danger of extinction, and evaluated their inhibitory activity against the collection of chytrid isolates. Through bioassays we confirmed the presence of chytrid-inhibitory bacterial genera in Costa Rican amphibians. However, we observed that the inhibition varied between different isolates of the same bacterial genus, and each bacterial isolation inhibited fungal isolation differently. In total, 14 bacterial isolates belonging to the genera Stenotrophomonas, Streptomyces, Enterobacter, Pseudomonas and Klebsiella showed inhibitory activity against all Bd isolates. Given the observed variation both in the pathogen and in the bacterial inhibition capacity, it is highly relevant to include local isolates and to consider the origin of the microorganisms when performing in vivo infection tests aimed at developing and implementing mitigation strategies for chytridiomycosis.

Community richness of amphibian skin bacteria correlates with bioclimate at the global scale.

Animal-associated microbiomes are integral to host health, yet key biotic and abiotic factors that shape host-associated microbial communities at the global scale remain poorly understood. We investigated global patterns in amphibian skin bacterial communities, incorporating samples from 2,349 individuals representing 205 amphibian species across a broad biogeographic range. We analysed how biotic and abiotic factors correlate with skin microbial communities using multiple statistical approaches. Global amphibian skin bacterial richness was consistently correlated with temperature-associated factors. We found more diverse skin microbiomes in environments with colder winters and less stable thermal conditions compared with environments with warm winters and less annual temperature variation. We used bioinformatically predicted bacterial growth rates, dormancy genes and antibiotic synthesis genes, as well as inferred bacterial thermal growth optima to propose mechanistic hypotheses that may explain the observed patterns. We conclude that temporal and spatial characteristics of the host's macro-environment mediate microbial diversity.