Potential Pathogens Research Articles

Genetic diversity and prevalence of emerging Rickettsiales in Yunnan Province: a large-scale study

BackgroundRickettsia and related diseases have been identified as significant global public health threats. This study involved comprehensive field and systematic investigations of various rickettsial organisms in Yunnan Province.MethodsBetween May 18, 2011 and November 23, 2020, field investigations were conducted across 42 counties in Yunnan Province, China, encompassing small mammals, livestock, and ticks. Preliminary screenings for Rickettsiales involved amplifying the 16S rRNA genes, along with additional genus- or species-specific genes, which were subsequently confirmed through sequencing results. Sequence comparisons were carried out using the Basic Local Alignment Search Tool (BLAST). Phylogenetic relationships were analyzed using the default parameters in the Molecular Evolutionary Genetics Analysis (MEGA) program. The chi-squared test was used to assess the diversities and component ratios of rickettsial agents across various parameters.ResultsA total of 7964 samples were collected from small mammals, livestock, and ticks through Yunnan Province and submitted for screening for rickettsial organisms. Sixteen rickettsial species from the genera Rickettsia, Anaplasma, Ehrlichia, Neoehrlichia, and Wolbachia were detected, with an overall prevalence of 14.72%. Among these, 11 species were identified as pathogens or potential pathogens to humans and livestock. Specifically, 10 rickettsial organisms were widely found in 42.11% (24 out of 57) of small mammal species. High prevalence was observed in Dremomys samples at 5.60%, in samples from regions with latitudes above 4000 m or alpine meadows, and in those obtained from Yuanmou County. Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis were broadly infecting multiple genera of animal hosts. In contrast, the small mammal genera Neodon, Dremomys, Ochotona, Anourosorex, and Mus were carrying individually specific rickettsial agents, indicating host tropism. There were 13 rickettsial species detected in 57.14% (8 out of 14) of tick species, with the highest prevalence (37.07%) observed in the genus Rhipicephalus. Eight rickettsial species were identified in 2375 livestock samples. Notably, six new Rickettsiales variants/strains were discovered, and Candidatus Rickettsia longicornii was unambiguously identified.ConclusionsThis large-scale survey provided further insight into the high genetic diversity and overall prevalence of emerging Rickettsiales within endemic hotspots in Yunnan Province. The potential threats posed by these emerging tick-borne Rickettsiales to public health warrant attention, underscoring the need for effective strategies to guide the prevention and control of emerging zoonotic diseases in China.Graphical

Functional Characterization of the Human BRCA1 ∆11 Splicing Isoforms in Yeast

BRCA1, a crucial tumor suppressor gene, has several splicing isoforms, including Δ9–11, Δ11, and Δ11q, which lack exon 11, coding for significant portions of the protein. These isoforms are naturally present in both normal and cancerous cells, exhibiting altered activity compared to the full-length BRCA1. Despite this, the impact on cancer risk of the germline intronic variants promoting the exclusive expression of these Δ11 isoforms remains uncertain. Consequently, they are classified as variants of uncertain significance (VUS), posing challenges for traditional genetic classification methods due to their rarity and complexity. Our research utilizes a yeast-based functional assay, previously validated for assessing missense BRCA1 variants, to compare the activity of the Δ11 splicing isoforms with known pathogenic missense variants. This approach allows us to elucidate the functional implications of these isoforms and determine whether their exclusive expression could contribute to increased cancer risk. By doing so, we aim to provide insights into the pathogenic potential of intronic VUS-generating BRCA1 splicing isoforms and improve the classification of BRCA1 variants.

Screening the Potential f Fungal Derived Bioherbicide in Weed Management

Synthetic herbicides have long been a cornerstone of modern agriculture, providing effective weed control but often at significant environmental and health costs. These chemicals can persist in the environment, leach into groundwater, and harm non-target organisms, including humans. Additionally, the overuse of synthetic herbicides has led to the development of herbicide-resistant weeds, further complicating weed management strategies. In response to these challenges, researchers and farmers alike are increasingly turning to bioherbicides derived from fungi as a sustainable alternative. Fungal bioherbicides harness the natural antagonistic properties of fungi to target weeds. Unlike synthetic herbicides, which are chemically synthesized and often broad-spectrum in action, fungal bioherbicides utilize either the fungi themselves as pathogens or their metabolites to disrupt weed growth. This approach offers several distinct advantages:Target Specificity: Fungal bioherbicides can be highly specific to certain weed species or even to specific stages of weed growth. This specificity reduces collateral damage to non-target plants and organisms, making them particularly suitable for environmentally sensitive areas such as organic farms, riparian zones, and protected ecosystems. Environmental Friendliness: Unlike synthetic herbicides that can persist in the environment and accumulate in soil and water bodies, fungal bioherbicides generally have lower persistence. They degrade more rapidly and often have minimal impact on non-target organisms, thereby preserving biodiversity and ecosystem health. Reduced Risk of Resistance: Synthetic herbicides often face the challenge of herbicide-resistant weeds, which evolve due to continuous and widespread use. Fungal bioherbicides, by contrast, pose a lower risk of resistance development. This is because they typically act through multiple modes of action or biochemical pathways within the weed, making it harder for weeds to develop resistance mechanisms. Research into fungal-derived bioherbicides is actively exploring and harnessing these advantages. Scientists are screening diverse fungal species to identify potent pathogens or metabolites that effectively inhibit weed growth. Moreover, advances in biotechnology and genetic engineering allow for the enhancement of fungal strains to optimize their bioherbicidal properties while ensuring safety and efficacy. One promising example is the use of fungal pathogens like Phomamacrostoma and Colletotrichum truncatum, which have demonstrated efficacy against various weed species including common agricultural weeds like velvetleaf and pigweed. These fungi infect weeds through mechanisms such as spore attachment, penetration of plant tissues, and secretion of phytotoxic metabolites that inhibit weed growth. In addition to their direct impact on weed management, fungal bioherbicides contribute to sustainable agricultural practices by reducing reliance on synthetic chemicals. They align with principles of integrated pest management (IPM) by offering a biological control method that complements cultural and mechanical weed control strategies. Moving forward, continued research and development efforts are essential to refine fungal bioherbicides, optimize application techniques, and expand their practical use in diverse agricultural settings. Challenges such as formulation stability, cost-effectiveness, and regulatory approvals also need to be addressed to facilitate widespread adoption by farmers.

Effects of Hypoxia on the Antibacterial Activity of Epidermal Mucus from Chilean Meagre (Cilus gilberti)

Comprehending the immune defense mechanisms of new aquaculture species, such as the Chilean meagre (Cilus gilberti), is essential for sustaining large-scale production. Two bioassays were conducted to assess the impact of acute and intermittent hypoxia on the antibacterial activity of juvenile Chilean meagre epidermal mucus against the potential pathogens Vibrio anguillarum and Vibrio ordalii. Lysozyme and peroxidase activities were also measured. In general, fish exposed to hypoxia showed a 9–30% reduction in mucus antibacterial activity at the end of hypoxic periods and after stimulation with lipopolysaccharide. However, following water reoxygenation, the activity of non-stimulated fish was comparable to that of fish in normoxic conditions, inhibiting bacterial growth by 35–52%. In the case of fish exposed to chronic hypoxia, the response against V. anguillarum increased by an additional 19.8% after 6 days of control inoculation. Lysozyme exhibited a similar pattern, while no modulation of peroxidase activity was detected post-hypoxia. These results highlight the resilience of C. gilberti to dissolved oxygen fluctuations and contribute to understanding the potential of mucus in maintaining the health of cultured fish and the development of future control strategies.

Leukotoxin A Production and Release by JP2 and Non-JP2 Genotype Aggregatibacter actinomycetemcomitans in Relation to Culture Conditions

Aggressive forms of periodontitis, especially in young patients, are often associated with an increased proportion of the Gram-negative bacterium Aggregatibacter actinomycetemcomitans of the microbiota of the affected periodontal sites. One of the virulence factors of A. actinomycetemcomitans is a leukotoxin (LtxA) that induces a pro-inflammatory cell death process in leukocytes. A. actinomycetemcomitans exhibits a large genetic diversity and different genotypes vary in LtxA production capacity. The genotype JP2 is a heavy LtxA producer due to a 530-base pair deletion in the promoter for the toxin genes, and this trait has been associated with an increased pathogenic potential. The present study focused on the production and release of LtxA by different A. actinomycetemcomitans genotypes and serotypes under various growth conditions. Four different strains of this bacterium were cultured in two different culture broths, and the amount of LtxA bound to the bacterial surface or released into the broths was determined. The cultures were examined during the logarithmic and the early stationary phases of growth. The JP2 genotype exhibited the highest LtxA production among the strains tested, and production was not affected by the growth phase. The opposite was observed with the other strains. The composition of the culture broth had no effect on the growth pattern of the tested strains. However, the abundant release of LtxA from the bacterial surface into the culture broth was found in the presence of horse serum. Besides confirming the enhanced leucotoxicity of the JP2 genotype, the study provides new data on LtxA production in the logarithmic and stationary phases of growth and the effect of media composition on the release of the toxin from the bacterial membrane.

Effects of Dietary Multi-Strain Probiotics on Growth Performance, Antioxidant Status, Immune Response, and Intestinal Microbiota of Hybrid Groupers (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂)

This study aims to examine the effects of the mixture of Bacillus cereus G1–11 and Exiguobacterium acetylicum G1–33, isolated from the gut of hybrid groupers (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂), on the host. The hybrid groupers were divided into a control (C, without any probiotics), B. cereus (BC, 1010 cfu/g), E. acetylicum (EA, 108 cfu/g), compound (mix, a 1:1 mixture of B. cereus and E. acetylicum), and positive reference group (P, Lactobacillus acidophilus, 5 × 108 cfu/L). Each group had four replicates, with 30 fish per replicate (53.30 ± 0.50 g), and were fed for 60 days. The results showed that adding probiotics to the feed significantly improved the weight gain, weight growth rate, specific growth rate, and digestive enzyme activities of hybrid groupers compared to the C group. The compound group was the most significant. In addition, composite probiotics added to feed significantly upregulated the expression levels of several growth-related genes in the liver and muscles. The activities of alkaline phosphatase, catalase, glutathione peroxidase, glutathione transferase, lysozyme, and total antioxidant capacity in the serum and liver were significantly influenced through mixed probiotic feeding. Moreover, the expression levels of several immune-related genes in the liver, spleen, and head kidney were significantly enhanced by adding single and mixed probiotics to feed, with the synergy of mixed probiotics being the best. An analysis of the gut microbiota showed that adding composite bacteria enhanced the richness and diversity of the gut microbiota, significantly increasing the relative abundance of potential probiotics (Cetobacterium and Microbacterium) while decreasing the presence of potential pathogens (Mycoplasma). Overall, our findings highlighted the efficacy of mixed probiotics (B. cereus and E. acetylicum) in enhancing growth performance, nutritional value of hybrid grouper feed, antioxidant capacity, immune response, and intestinal health, in finding the best combination of functional feed additives.

Point-of-use filtration units as drinking water distribution system sentinels

Municipal drinking water distribution systems (DWDSs) and associated premise plumbing (PP) systems are vulnerable to proliferation of opportunistic pathogens, even when chemical disinfection residuals are present, thus presenting a public health risk. Monitoring the structure of microbial communities of drinking water is challenging because of limited continuous access to faucets, pipes, and storage tanks. We propose a scalable household sampling method, which uses spent activated carbon and reverse osmosis (RO) membrane point-of-use (POU) filters to evaluate mid- to long-term occurrence of microorganisms in PP systems that are relevant to consumer exposure. As a proof of concept, POU filter microbiomes were collected from four different locations and analyzed with 16S rRNA gene amplicon sequencing. The analyses revealed distinct microbial communities, with occasional detection of potential pathogens. The findings highlight the importance of local, and if possible, continuous monitoring within and across distribution systems. The continuous operation of POU filters offers an advantage in capturing species that may be missed by instantaneous sampling methods. We suggest that water utilities, public institutions, and regulatory agencies take advantage of end-of-life POU filters for microbial monitoring. This approach can be easily implemented to ensure drinking water safety, especially from microbes of emerging concerns; e.g., pathogenic Legionella and Mycobacterium species.

Assessing marine ecosystem health using multi-omic analysis of blue mussel liquid biopsies: A case study within a national marine park

Marine ecosystems are under escalating threats from myriad environmental stressors, necessitating a deeper understanding of their impact on biodiversity and the health of sentinel organisms. In this study, we carried out a spatiotemporal multi-omic analysis of liquid biopsies collected from mussels (Mytilus spp.) in marine ecosystems of a national park. We delved into the epigenomic, transcriptomic, glycomic, proteomic, and microbiomic profiles to unravel the intricate interplay between ecosystem biodiversity and mussels' biological response to their environments. Our analysis revealed temporal fluctuations in the alpha diversity of the circulating microbiome associated with human activities. Analysis of the hemolymphatic circulating cell-free DNA (ccfDNA) provided information on the biodiversity and the presence of potential pathogens. Epigenomic analysis revealed widespread hypomethylation sites within the mitochondrial (mtDNA). Comparative transcriptomic and glycomic analyses highlighted differences in metabolic pathways and genes associated with immune and wound healing functions. This study demonstrates the potential of multi-omic analysis of liquid biopsy in sentinel to provide a holistic view of human activities' environmental impacts on marine coastal ecosystems. Overall, this approach has the potential to enhance the effectiveness and efficiency of various conservation efforts, leading to more informed decision-making and better outcomes for biodiversity and ecosystem conservation.

Role of Milk-Derived Antimicrobial Peptides and Their Future Perspectives in Pharmaceutical/ Dairy Industries

Milk is a good source of bioactive peptides of high nutritive/ pharmaceutical value. In recent decades, the curiosity about bioactive milk peptides has been increasing because of their positive impact on physiological and metabolic functions in human health. A variety of naturally acquired bioactive peptides have been found in fermented dairy products like sour milk and cheese. Initially, these bioactive peptides are found as inactive forms within the precursor protein sequence and can be released in different ways. They can be generated by gastrointestinal digestion of milk, fermentation of milk with proteolytic microorganisms, or hydrolysis via proteolytic enzymes. Once they are released from the precursor protein sequence, they influence body functions and human health. Peptides derived from cow milk exert multifunctional properties, including antimi-crobial, antidiabetic, antihypertensive, anti-inflammatory, immune-modulatory, antioxidant activ-ities, etc. Bioactive antimicrobial peptides are observed in the Cow milk proteins. The Cow milk peptides afford the non-immune-based defense and control for various microbial infections. These activities depend upon their amino acid composition/ sequence. Potential pathogens are con-stantly exposed to mucosal surfaces (lungs and small intestine). The risk of chronic disease was inhibited by antimicrobial peptides, which may afford natural immune protection with the avoid-ance of microbial resistance. In this regimen, the present review summarizes the milk-derived an-timicrobial peptides obtained from casein/ whey protein, along with their future perspectives in the pharmaceutical and dairy industries.

Kluyvera ascorbata: An Emerging Pathogen and Rare Cause of Urinary Tract Infection in Immunocompetent Patients at a Tertiary Care Center in North India

Abstract Kluyvera spp. is a Gram-negative bacillus and was discovered by Kluyver and van Niel, included in the family Enterobacteriaceae. We report two cases of urinary tract infection due to Kluyvera ascorbata. The first case was a 61-year-old male, who was admitted to the nephrology department of the hospital with chief complaints of fever with chills from 1 week, abdominal pain, and difficulty in passing urine. The second case was a 29-year-old female, who presented to the medicine department of the hospital with a 4-day history of fever with associated chills and rigor, abdominal pain, chills, and weakness. These patients were treated with nitrofurantoin given orally for 7 days they recovered completely. This case series highlights the role of K. ascorbata, and in general of Kluyvera species, as an unusual but potentially dangerous pathogen, the need for prompt identification to determine potential pathogenicity in the immunocompetent as well as in the immunocompromised host, and to assess the efficacy of antibiotics such as carbapenems and nitrofurantoin.

Distinct effects of phyllosphere and rhizosphere microbes on invader Ageratina adenophora during its early life stages.

Microbes strongly affect invasive plant growth. However, how phyllosphere and rhizosphere soil microbes distinctively affect seedling mortality and growth of invaders across ontogeny under varying soil nutrient levels remains unclear. In this study, we used the invader Ageratina adenophora to evaluate these effects. We found that higher proportions of potential pathogens were detected in core microbial taxa in leaf litter than rhizosphere soil and thus leaf inoculation had more adverse effects on seed germination and seedling survival than soil inoculation. Microbial inoculation at different growth stages altered the microbial community and functions of seedlings, and earlier inoculation had a more adverse effect on seedling survival and growth. The soil nutrient level did not affect microbe-mediated seedling growth and the relative abundance of the microbial community and functions involved in seedling growth. The effects of some microbial genera on seedling survival are distinct from those on growth. Moreover, the A. adenophora seedling-killing effects of fungal strains isolated from dead seedlings by non-sterile leaf inoculation exhibited significant phylogenetic signals, by which strains of Allophoma and Alternaria generally caused high seedling mortality. Our study stresses the essential role of A. adenophora litter microbes in population establishment by regulating seedling density and growth.

Impact of Catheter-Drawn Blood Cultures on Patient Management: A Multicenter, Retrospective Cohort Study.

Nosocomial bloodstream infections associated with intravascular catheters pose significant financial burden, morbidity, and mortality. There is much debate about whether or not blood cultures should be drawn through central venous catheters, and while guidelines advocate for catheter-drawn cultures when catheter infection is suspected, there is variable practice in this regard. We performed a retrospective cohort study assessing episodes of positive catheter-drawn blood cultures with concomitant negative percutaneously-drawn cultures in tertiary care hospitals in the United States and Spain. We identified 143 episodes in 122 patients meeting inclusion criteria. Thirty percent of such episodes revealed growth of potential pathogens such as Staphylococcus aureus. Overall, 21% of follow-up percutaneously-drawn blood cultures obtained within 48 hours revealed growth of the same microbe after an episode of positive catheter-drawn blood cultures with negative concomitant percutaneously-drawn cultures (33% when potential pathogens were isolated; 16% when common skin contaminants were isolated). Patients with cultures growing pathogenic organisms were more likely to receive targeted antimicrobial therapy and have their catheters removed sooner. Many episodes of positive catheter-drawn blood cultures with concomitant negative percutaneously-drawn cultures lead to growth from percutaneously-drawn follow-up blood cultures. Thus, such initial discordant results should not be disregarded. Our findings advocate for a nuanced approach to blood culture interpretation, emphasizing the value of catheter-drawn blood cultures in clinical decision making and management.

The diversity and risk of potential pathogenic bacteria on the surface of glaciers in the southeastern Tibetan Plateau

Glaciers, which constitute the world's largest global freshwater reservoir, are also natural microbial repositories. The frequent pandemic in recent years underscored the potential biosafety risks associated with the release of microorganisms from the accelerated melting of glaciers due to global warming. However, the characteristics of pathogenic microorganisms in glaciers are not well understood. The glacier surface is the primary area where glacier melting occurs that is often the main subject of research on the dynamics of pathogenic microbial communities in efforts to assess glacier biosafety risks and devise preventive measures. In this study, high-throughput sequencing and quantitative polymerase chain reaction methods were employed in analyses of the composition and quantities of potential pathogenic bacteria on the surfaces of glaciers in the southeastern Tibetan Plateau. The study identified 441 potential pathogenic species ranging from 215 to 4.39 × 1011 copies/g, with notable seasonal and environmental variations being found in the composition and quantity of potential pathogens. The highest level of diversity was observed in April and snow, while the highest quantities were observed in October and cryoconite. Host analysis revealed that >70 % of the species were pathogens affecting animals, with the highest proportion of zoonotic pathogens being observed in April. Analysis of aerosols and glacial meltwater dispersion suggested that these microbes originated from West Asia, primarily affecting the central and southern regions of China. Null model analysis indicated that the assembly of potential pathogenic microbial communities on glacier surfaces was largely governed by deterministic processes. In conclusion, potential pathogenic bacteria on glacier surfaces mainly originated from the snow and exhibited significant temporal and spatial variation patterns. These findings can be used to enhance researchers' ability to predict potential biosafety risks associated with pathogenic bacteria in glaciers and to prevent their negative impact on populations and ecological systems.

Environmentally responsive changes in mucus indicators and microbiota of Chinese sturgeon Acipenser sinensis

The impact of environmental factors on the health of the endangered Chinese sturgeon (Acipenser sinensis) and the potential hazards associated with sample collection for health monitoring pose urgent need to its conservation. In this study, Chinese sturgeons were selected from indoor and outdoor environments to evaluate metabolic and tissue damage indicators, along with a non-specific immune enzyme in fish mucus. Additionally, the microbiota of both water bodies and fish mucus were determined using 16S rRNA high-throughput sequencing. The correlation between the indicators and the microbiota was investigated, along with the measurement of multiple environmental factors. The results revealed significantly higher levels of two metabolic indicators, total protein (TP) and cortisol (COR) in indoor fish mucus compared to outdoor fish mucus (p < 0.05). The activities of acid phosphatase (ACP), alkaline phosphatase (ALP), creatine kinase (CK), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were significantly higher in indoor fish, serving as indicators of tissue damage (p < 0.05). The activity of lysozyme (LZM) was significantly lower in indoor fish (p < 0.01). Biomarker analysis at the phylum and genus levels in outdoor samples revealed that microorganisms were primarily related to the catabolism of organic nutrients. In indoor environments, microorganisms displayed a broader spectrum of functions, including ecological niche establishment, host colonization, potential pathogenicity, and antagonism of pathogens. KEGG functional enrichment corroborated these findings. Dissolved oxygen (DO), electrical conductivity (EC), ammonia nitrogen (NH3-N), turbidity (TU), and chemical oxygen demand (COD) exerted effects on outdoor microbiota. Temperature (TEMP), nitrate (NO3-), total phosphorus (TP), and total nitrogen (TN) influenced indoor microbiota. Changes in mucus indicators, microbial structure, and function in both environments were highly correlated with these factors. Our study provides novel insights into the health impacts of different environments on Chinese sturgeon using a non-invasive method.

Targeting S. aureus Extracellular Vesicles: A New Putative Strategy to Counteract Their Pathogenic Potential.

Long-term inflammatory skin disease atopic dermatitis is characterized by dry skin, itching, and eczematous lesions. During inflammation skin barrier protein impairment promotes S. aureus colonisation in the inflamed skin, worsening AD patient's clinical condition. Proteomic analysis revealed the presence of several immune evasion proteins and virulence factors in S. aureus extracellular vesicles (EVs), suggesting a possible role for these proteins in the pathophysiology of atopic dermatitis. The objective of this study is to assess the efficacy of a wall fragment obtained from a patented strain of C. acnes DSM28251 (c40) and its combination with a mucopolysaccharide carrier (HAc40) in counteract the pathogenic potential of EVs produced by S. aureus ATCC 14458. Results obtained from in vitro studies on HaCaT keratinocyte cells showed that HAc40 and c40 treatment significantly altered the size and pathogenicity of S. aureus EVs. Specifically, EVs grew larger, potentially reducing their ability to interact with the target cells and decreasing cytotoxicity. Additionally, the overexpression of the tight junctions mRNA zona occludens 1 (ZO1) and claudin 1 (CLDN1) following EVs exposure was decreased by HAc40 and c40 treatment, indicating a protective effect on the epidermal barrier's function. These findings demonstrate how Hac40 and c40 may mitigate the harmful effects of S. aureus EVs. Further investigation is needed to elucidate the exact mechanisms underlying this interaction and explore the potential clinical utility of c40 and its mucopolysaccharide carrier conjugate HAc40 in managing atopic dermatitis.

Multi-omics analysis of a fecal microbiota transplantation trial identifies novel aspects of acute graft-versus-host disease pathogenesis.

Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic hematopoietic cell transplantation (alloHCT) associated with gut microbiota disruptions. However, whether therapeutic microbiota modulation prevents aGVHD is unknown. We conducted a randomized, placebo-controlled trial of third-party fecal microbiota transplantation (FMT) administered at the peak of microbiota injury in 100 patients with acute myeloid leukemia receiving induction chemotherapy and alloHCT recipients. Despite improvements in microbiome diversity, expansion of commensals, and shrinkage of potential pathogens, aGVHD occurred more frequently after FMT than placebo. Although this unexpected finding could be explained by clinical differences between the two arms, we asked whether a microbiota explanation might be also present. To this end, we performed multi-omics analysis of pre- and post-intervention gut microbiome and serum metabolome. We found that post-intervention expansion of Faecalibacterium, a commensal genus with gut-protective and anti-inflammatory properties under homeostatic conditions, predicted a higher risk for aGVHD. Faecalibacterium expansion occurred predominantly after FMT and was due to engraftment of unique donor taxa, suggesting that donor Faecalibacterium-derived antigens might have stimulated allogeneic immune cells. Faecalibacterium and ursodeoxycholic acid (an anti-inflammatory secondary bile acid) were negatively correlated, offering an alternative mechanistic explanation. In conclusion, we demonstrate context dependence of microbiota effects where a normally beneficial bacteria may become detrimental in disease. While FMT is a broad, community-level intervention, it may need precision engineering in ecologically complex settings where multiple perturbations (e.g. antibiotics, intestinal damage, alloimmunity) are concurrently in effect.

Infections caused by Slackia exigua: A single-center experience and literature review.

Slackia exigua, originally classified as Eubacterium exiguum, is a Gram-positive, asaccharolytic, rod-shaped anaerobic bacterium. The virulence factors of S. exigua have not been accurately identified. The objective of the study is to evaluate the pathogenic potential of S. exigua by presenting the cases of infections diagnosed at our hospital laboratory. Additionally, we reviewed the literature to summarize the experience with S. exigua infections to clarify, in the light of current knowledge, the clinical picture, diagnostic, and therapeutic issues related to this anaerobic bacterium. We reported eleven severe human infections caused by S. exigua. All patients required hospitalization. Nine of the cases involved chronic infections in the stomatognathic system, in two patients, skin infections were diagnosed. As it is known, S. exigua is a component of the human microbiota; however, it can cause opportunistic infections, particularly in the case of translocation outside its natural habitat. A critical literature analysis revealed that S. exigua can be responsible for bacteremia, meningitis, tissue necrosis, periprosthetic joint infection, and osteomyelitis. Several studies have been published regarding the determination of drug susceptibility of S. exigua. The isolated strains were susceptible to most antibiotics used for the treatment of anaerobic infections. The interpretation of antimicrobial susceptibility testing for some slow-growing in vitro, infrequently causing infections anaerobic bacteria, such as S. exigua, is based on The European Committee on Antimicrobial Susceptibility Testing (EUCAST) additional guidance taking into account the determination of drug susceptibility for groups of microorganisms for which cut-off values have not been developed.

Disease Occurrence and Climatic Factors Jointly Structure Pomelo Leaf Fungal Succession in Disturbed Agricultural Ecosystem.

For perennial plants, newly emerged organs are fresh hot spots for environmental microbes to occupy and assemble to form mature microbial communities. In the microbial community, some commensal fungi can play important roles in microbial succession, thus significantly improving host plant growth and disease resistance. However, their participating patterns in microbial assembly and succession remain largely unknown. In this study, we profiled the fungal community and found a similar fungal succession pattern of spring-emerged leaves from March to October in two pomelo orchards. Specifically, the fungal species, tracked on the old leaves, dominated the spring leaves after emergence and then decreased in relative abundance. This reduction in priority effects on the spring leaves was then followed by an increase in the number of observed species, Shannon and phylogenetic diversity indices, and the pathogen-associated fungal groups. In addition, we found that the temporal fungal succession on the spring leaves highly correlated with the disease occurrence in the orchards and with the temperature and precipitation variation from spring to summer. Of the pathogen-associated fungal groups, an increase in the relative abundance of Mycosphaerellaceae, hosting the causal agent of citrus greasy spot, correlated with the occurrence of the disease, while the relative abundance of Diaporthaceae, hosting the causal agent of melanose, was extremely low during the fungal succession. These results confirm that the two kinds of pathogen-associated fungal groups share different lifestyles on citrus, and also suggest that the study of temporal fungal succession in microbial communities can add to our understanding of the epidemiology of potential plant pathogens.

The role of antibiotic exposure and the effects of breastmilk and human milk feeding on the developing infant gut microbiome.

The World Health Organization (WHO) recommends exclusive breastfeeding for the first 6 months of life followed by complementary foods and sustained breastfeeding for at least 2 years, underscoring its pivotal role in reducing infant mortality and preventing various illnesses. This perspective delves into the intricate relationship between breastfeeding practices, early life antibiotic exposure, and infant gut microbiome development, highlighting their profound influence on child health outcomes. Antibiotics are extensively prescribed during pregnancy and childhood, disrupting the microbiome, and are related to increased risks of allergies, obesity, and neurodevelopmental disorders. Breastfeeding is a significant determinant of a healthier gut microbiome, characterized by higher levels of beneficial bacteria such as Bifidobacterium and lower levels of potential pathogens. Despite widespread recognition of the benefits of breastfeeding, gaps persist in healthcare practices and support mechanisms, exacerbating challenges faced by breastfeeding families. This highlights the pressing need for comprehensive research encompassing breastfeeding behaviors, human milk intake, and their impact on infant health outcomes. Additionally, promoting awareness among healthcare providers and families regarding the detrimental effects of unnecessary formula supplementation could facilitate informed decision-making and bolster exclusive breastfeeding rates. Moreover, donor human milk (DHM) is a promising alternative to formula, potentially mitigating disruptions to the infant gut microbiome after antibiotic exposure. Overall, prioritizing breastfeeding support interventions and bridging research gaps are essential steps towards improving child health outcomes on a global scale.

Genomic Characterization of Multidrug-Resistant Enterobacteriaceae Clinical Isolates from Southern Thailand Hospitals: Unraveling Antimicrobial Resistance and Virulence Mechanisms.

The emergence and spread of antimicrobial resistance (AMR) among Enterobacteriaceae pose significant threats to global public health. In this study, we conducted a short-term surveillance effort in Southern Thailand hospitals to characterize the genomic diversity, AMR profiles, and virulence factors of Enterobacteriaceae strains. We identified 241 carbapenem-resistant Enterobacteriaceae, of which 12 were selected for whole-genome sequencing (WGS) and genome analysis. The strains included Proteus mirabilis, Serratia nevei, Klebsiella variicola, Klebsiella aerogenes, Klebsiella indica, Klebsiella grimontii, Phytobacter ursingii, Phytobacter palmae, Kosakonia spp., and Citrobacter freundii. The strains exhibited high levels of multidrug resistance, including resistance to carbapenem antibiotics. Whole-genome sequencing revealed a diverse array of antimicrobial resistance genes (ARGs), with strains carrying genes for ß-lactamase, efflux pumps, and resistance to other antibiotic classes. Additionally, stress response, metal tolerance, and virulence-associated genes were identified, highlighting the adaptability and pathogenic potential of these strains. A plasmid analysis identified several plasmid replicons, including IncA/C2, IncFIB(K), and Col440I, as well as several plasmids identical to those found globally, indicating the potential for the horizontal gene transfer of ARGs. Importantly, this study also identified a novel species of Kosakonia spp. PSU27, adding to the understanding of the genetic diversity and resistance mechanisms of Enterobacteriaceae in Southern Thailand. The results reported in this study highlight the critical importance of implementing effective antimicrobial management programs and developing innovative treatment approaches to urgently tackle AMR.