The enteric microbiota is an established reservoir for multidrug-resistant organisms that present urgent clinical and public health threats. Observational data and small interventional studies suggest that microbiome interventions, such as fecal microbiota products and characterized live biotherapeutic bacterial strains, could be an effective antibiotic-sparing prevention approach to address these threats. However, bacterial colonization is a complex ecological phenomenon that remains understudied in the context of the human gut. Antibiotic resistance is one among many adaptative strategies that impact long-term colonization. Here we review and synthesize evidence of how bacterial competition and differential fitness in the context of the gut present opportunities to improve mechanistic understanding of colonization resistance, therapeutic development, patient care, and ultimately public health.

The application of fecal microbiota transplantation (FMT) as a therapeutic strategy to directly modify the makeup of the gut microbiota has made significant progress in the last few decades. The gut microbiota, a sizable microbial community present in the human gut, is essential for digestion, immunomodulation, and nutrition absorption. Alternatively, a growing body of research indicates that gut microbiota is a key contributor to cancer, and intratumoral bacteria are considered to be crucial "accomplices" in the development and metastasis of malignancies. The exceptional clinical effectiveness of FMT in treating melanoma patients has been adequately established in earlier research, which has created new avenues for the diagnosis and treatment of cancer and sparked an increasing interest in the treatment and prevention of other cancers. However, further research on the function and mechanisms of the gut microbiota is required to properly comprehend the impact and role of these organisms in tumor regulation. In this article, we present a detailed account of the influence of FMT on the entire course of cancer patients' illness and treatment, from tumor development, metastasis, and invasion, to the impact and application of treatment and prognosis, as well as address the associated mechanisms.

Fecal microbiota transplantation (FMT) has shown promise as a treatment for recurrent or refractory Clostridioides difficile infections. This study aimed to evaluate the decolonization effects of FMT on vancomycin-resistant Enterococcus (VRE).

This feasibility trial prospectively recruited patients with more than three recurrent VRE infections. FMT was performed by infusing fecal microbiota solutions from healthy, unrelated donors into the participants' guts via colonoscopy. Fecal microbiota profiles before and after FMT were analyzed.

Three of the six patients (50%) experienced VRE decolonization after FMT, lasting over six months. Baseline analysis revealed that patients who achieved decolonization had greater microbial diversity compared to those with persistent VRE colonization. Throughout the study, there were no adverse events observed in the patients after FMT. Elevated alpha diversity persisted in responders, while non-responders showed no significant changes. In responders, the abundance of genera within the phylum Firmicutes (Bacillota), including Anaerostipes, Blautia, Faecalibacterium, and Ruminococcus, and the genus Collinsella within the phylum Actinobacteriota increased steadily through 180 days post-FMT.

FMT may leverage bacterial strain competition to facilitate decolonization of drug-resistant organisms, with successful VRE decolonization potentially linked to increased abundance of phyla Firmicutes and Actinobacteriota over 6 months.

Antimicrobial resistance (AMR) has become a major and escalating global health threat, undermining the effectiveness of current antibiotic and antimicrobial therapies. The rise of multidrug-resistant bacteria has led to increasingly difficult-to-treat infections, resulting in higher morbidity, mortality, and healthcare costs. Tackling this crisis requires the development of novel antimicrobial agents, optimization of current therapeutic strategies, and global initiatives in infection surveillance and control. Recent studies highlight the crucial role of the human gut microbiota in defending against AMR pathogens. A balanced microbiota protects the body through mechanisms such as colonization resistance, positioning it as a key ally in the fight against AMR. In contrast, gut dysbiosis disrupts this defense, thereby facilitating the persistence, colonization, and dissemination of resistant pathogens. This review will explore how gut microbiota influence drug-resistant bacterial infections, its involvement in various types of AMR-related infections, and the potential for novel microbiota-targeted therapies, such as fecal microbiota transplantation, prebiotics, probiotics, phage therapy. Elucidating the interactions between gut microbiota and AMR pathogens will provide critical insights for developing novel therapeutic strategies to prevent and treat AMR infections. While previous reviews have focused on the general impact of the microbiota on human health, this review will specifically look at the latest research on the interactions between the gut microbiota and the evolution and spread of AMR, highlighting potential therapeutic strategies.

Pouchitis is common among patients with ulcerative colitis (UC) who have had colectomy with ileal pouch-anal anastomosis. Antibiotics are first-line therapy for pouch inflammation, increasing the potential for gut colonization with multi-drug resistant organisms (MDRO). Fecal microbial transplant (FMT) is being studied in the treatment of pouchitis and in the eradication of MDRO. Prior work using aerobic antibiotic culture disks suggests that some patients with chronic pouchitis may regain fluoroquinolone sensitivity after FMT. However, gut MDRO include anaerobic, fastidious organisms that are difficult to culture using traditional methods.

We aimed to assess whether FMT reduced the abundance of antibiotic resistance genes (ARG) or affected resistome diversity, evenness, or richness in patients with chronic pouchitis.

We collected clinical characteristics regarding infections and antibiotic exposures for 18 patients who had previously been enrolled in an observational study investigating FMT as a treatment for pouchitis. Twenty-six pre- and post-FMT stool samples were analyzed using FLASH (Finding Low Abundance Sequences by Hybridization), a CRISPR/Cas9-based shotgun metagenomic sequence enrichment technique that detects acquired and chromosomal bacterial ARGs. Wilcoxon rank sum tests were used to assess differences in clinical characteristics, ARG counts, resistome diversity and ARG richness, pre- and post-FMT.

All 13 of the patients with sufficient stool samples for analysis had recently received antibiotics for pouchitis prior to a single endoscopic FMT. Fecal microbiomes of all patients had evidence of multi-drug resistance genes and ESBL resistance genes at baseline; 62% encoded fluoroquinolone resistance genes. A numerical decrease in overall ARG counts was noted post-FMT, but no statistically significant differences were noted (P = 0.19). Richness and diversity were not significantly altered. Three patients developed infections during the 5-year follow-up period, none of which were associated with MDRO.

Antibiotic resistance genes are prevalent among antibiotic-exposed patients with chronic pouchitis. FMT led to a numerical decrease, but no statistically significant change in ARG, nor were there significant changes in the diversity, richness, or evenness of ARGs. Further investigations to improve FMT engraftment and to optimize FMT delivery in patients with inflammatory pouch disorders are warranted.

Vancomycin-resistant Enterococcus faecium (VREfm) has become a critical opportunistic pathogen, urgently requiring new antimicrobial strategies due to its rising prevalence and significant impact on patient safety and healthcare costs. VREfm continues to evolve through mutations and the acquisition of new genes via horizontal gene transfer, contributing to resistance against several last-resort antibiotics. Although primarily hospital-associated, VREfm are also detected in the community, food chain, livestock, and environmental sources like wastewater, indicating diverse transmission pathways and the need for a One Health approach. Advances in genomics have shed light on VREfm's persistence in hospital settings, particularly its adaptation to the gastrointestinal tract of hospitalized patients, recent clonal shifts, and the dominance of specific clonal lineages. Despite extensive research, significant gaps remain in understanding the molecular mechanisms behind VREfm's unique adaptation to clinical environments. In this review, we aim to present an overview of VREfm current prevalence, mechanisms of resistance, and unveil the adaptive traits that have facilitated VREfm's rise and global success. A particular focus is given to key plasmids, namely linear plasmids, virulence factors, and bacteriocins as potential drivers in the global emergence of the ST78 clonal lineage. We also address diagnostic challenges and the limited treatment options available for VREfm, as well as emerging antibiotic alternatives aimed at restoring gut microbiota balance and curbing VREfm proliferation. A multifaceted approach combining research, clinical practices, and public health policies is crucial to mitigate the impact of this superbug and preserve antimicrobial effectiveness for future generations.

Patients undergoing autologous stem cell transplantation (auto-SCT) face elevated risks of infections. Additionally, patients colonized in the gastrointestinal tract with antibiotic-resistant bacteria (ARB) are at higher risk of infection with ARB and other infections. Therefore, patients colonized with ARB before auto-SCT should present with an exceptionally high incidence of infections. According to current literature, ARB colonization is the surrogate marker for dysbiosis, which is known to be associated with a diagnosis of multiple myeloma (MM). Given that, this retrospective study aimed to assess the influence of ARB colonization on infection rates, hematopoiesis regeneration, mucositis, overall survival, and progression-free survival following auto-SCT in MM. Data from 138 MM patients undergoing 141 auto-SCT were analyzed, with 15% showing ARB colonization. Among colonized patients, ESBL-producing gram-negative rods predominated. Patients with gut ARB colonization had significantly higher infection rates than non-colonized individuals (52 vs. 26%, P = 0.02), particularly bloodstream infections (43% vs. 14%, P = 0.004). Colonized patients also tended to exhibit shorter survival rates although there was no statistical significance (1-year and 2-year OS; non-colonized vs. colonized; 97 and 92% vs. 90 and 86%; p = 0.054). Based on our results, gut colonization before auto-SCT negatively affects treatment outcomes.

Exposure of critically ill patients to antibiotics lead to intestinal dysbiosis, which often manifests as antibiotic-associated diarrhoea. Faecal microbiota transplantation restores gut microbiota and may lead to faster resolution of diarrhoea.

Into this prospective, multi-centre, randomized controlled trial we will enrol 36 critically ill patients with antibiotic-associated diarrhoea. We will exclude patients with ongoing sepsis, need of systemic antibiotics, or those after recent bowel surgery or any other reason that prevents the FMT. Randomisation will be in 1:1 ratio. Patients in the control group will receive standard treatment based on oral diosmectite. In the intervention group, patients will receive, in addition to the standard of care, faecal microbiota transplantation via rectal tube, in the form of a preparation mixed from 7 thawed aliquots (50 mL) made from fresh stool of 7 healthy unrelated donors and quarantined deep frozen for 3 to 12 months. Primary outcome is treatment failure defined as intervention not delivered or diarrhoea persisting at day 7 after randomisation. Secondary outcomes include safety measures such as systemic inflammatory response, adverse events, and also diarrhoea recurrence within 28 days. Exploratory outcomes focus on gut barrier function and composition of intestinal microbiota.

Faecal microbiota transplantation has been effective for dysbiosis in non-critically ill patients with recurrent C. difficile infections and it is plausible to hypothesize that it will be equally effective for symptoms of dysbiosis in the critically ill patients. In addition, animal experiments and observational data suggest other benefits such as reduced colonization with multi-drug resistant bacteria and improved gut barrier and immune function. The frozen faeces from unrelated donors are immediately available when needed, unlike those from the relatives, who require lengthy investigation. Using multiple donors maximises graft microbiota diversity. Nonetheless, in vulnerable critically ill patients, Faecal microbiota transplantation might lead to bacterial translocation and unforeseen complications. From growing number of case series it is clear that its off label use in the critically ill patients is increasing and that there is a burning need to objectively assess its efficacy and safety, which this trial aims.

www.clinicaltrials.gov (NCT05430269).

To evaluate the therapeutic potential of fecal microbiota transplantation (FMT) in treating severe pneumonia patients with concurrent pan-drug resistant Klebsiella pneumoniae infection.

A case report of a 95-year-old female patient with severe pneumonia, complicated by pan-resistant bacterial infections, is presented. The patient was diagnosed with severe pneumonia caused by COVID-19, along with co-infections of Staphylococcus hominis, Enterococcus faecalis, Candida tropicalis, Pseudomonas aeruginosa, ESBL-producing pan-drug resistant Klebsiella pneumoniae and pan-resistant Acinetobacter baumannii. During hospitalization, the patient underwent comprehensive treatments, including antimicrobials, mechanical ventilation, and fiberoptic bronchoscopic alveolar lavage. FMT was administered following the failure of conventional treatments to resolve recurrent diarrhea, increased sputum production, and persistent pan-drug resistant Klebsiella pneumoniae infection.

Post-FMT, the patient exhibited significant clinical improvement, including reduced sputum production, cessation of diarrhea, and the normalization of respiratory symptoms. Gut microbiota analysis revealed that FMT enhanced the abundance of beneficial microbiota and suppressed Klebsiella pneumoniae, and the patient was successfully discharged after 133 days of hospitalization.

FMT emerged as a pivotal intervention in the management of this severe pneumonia case, suggesting its efficacy in restoring gut microbiota balance and aiding recovery from multi-drug-resistant infections. This case underscores the potential of FMT as a therapeutic option in severe pulmonary infections, especially in the context of antibiotic resistance in severe pneumonia patients.

Lower diversity of the gut microbiome prior to allogeneic haematopoietic cell transplantation (HCT) correlates with reduced survival after the intervention. Most patients undergoing HCT for a haematological malignancy have previously received intensive chemotherapy, resulting in prolonged neutropenic episodes requiring broad-spectrum antibiotics; use of these has been linked to reduced microbiome diversity. Intestinal microbiota transplant (IMT) is a novel treatment approach that restores this diversity. We hypothesised that IMT performed prior to initiation of HCT conditioning restores microbiome diversity during the early stages of HCT, leading to decreased frequency of complications and improved outcomes of HCT.

50 adult patients receiving allogeneic HCT will be recruited into this phase IIa trial and randomised 1:1 to receive capsulised IMT or matched placebo shortly prior to initiation of HCT conditioning and followed for up to 12 months. The primary outcome will be to assess the increase in alpha diversity between pre-IMT and that measured at ~42 days after IMT administration (day +28 of HCT), comparing the difference between patients receiving IMT compared with placebo. Secondary outcomes will include tolerability, the dynamics of gut microbiome diversity metrics and taxonomy over all time points assessed, as well as clinical outcomes (including burden of invasive infections, days of fever, admission to intensive care, development of graft-vs-host disease and mortality).

This study was approved by a UK Research Ethics Committee (REC reference: 23/NE/0105). Dissemination of results will be in concert with patient and public involvement group input and is expected to be primarily via abstract presentation at conferences and manuscripts in peer-reviewed journals.

NCT6355583; EudraCT: 2022-003617-10.

Patients undergoing hematopoietic cell transplantation (HCT) have an increased risk of developing severe infections. In recent years, bloodstream infections caused by Gram-negative bacteria have been increasingly reported among HCT recipients, and many of these infections are caused by bacterial strains of the Enterobacterales order. Among these pathogens, particularly concerning are the multidrug-resistant Enterobacterales (MDRE), such as Extended Spectrum β-lactamase-producing Enterobacterales and Carbapenem-resistant Enterobacterales, since infections caused by these pathogens are difficult to treat due to the limited antimicrobial options and are associated with worse transplant outcomes. We summarized the evidence from studies published in PubMed and Scopus on the burden of MDRE infections in HCT recipients, and strategies for the management and prevention of these infections, including strict adherence to recommended infection control practices and multidisciplinary antimicrobial stewardship, the use of probiotics, and fecal microbiota transplantation, are also discussed.

The prevalence of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) and carbapenem-resistant Enterobacterales (CRE) has become a global public health problem. ESBL-E/CRE colonization can increase the risk of infection in patients and lead to poor disease prognosis. We conducted a systematic review and meta-analysis to evaluate current decolonization strategies regarding ESBL-E/CRE and their efficacy. A literature search was conducted until August 2023 on the five databases to review decolonization strategies associated with ESBL-E/CRE. A meta-analysis was conducted using RevMan 5.4 to compare differences in the decolonization strategy with placebo controls. The primary outcome was decolonization rates, with secondary outcomes of attributable death and adverse events. Quality of identified studies was determined using the Newcastle-Ottawa scale and cochrane risk assessment tool. Random and fixed effects meta-analyses were performed to calculate pooled value. A total of 25 studies were included. In five randomized controlled trial (RCT) studies, the decolonization effect of selective digestive decontamination(SDD) on ESBL-E/CRE at the end of treatment was significantly better in the experimental group than the controls [risk radio (RR): 3.30; 95% CI 1.78-6.14]. In three n-RCT studies, the decolonization effect in the experimental group was still better than the controls one month after SDD therapy [odds ratio (OR): 4.01; 95% CI 1.88-8.56]. The combined decolonization rates reported by six single-arm trial studies of SDD therapy ranged from 53.8 to 68.0%. Additionally, TSA analysis confirmed the effectiveness of SDD therapy. In studies on Faecal microbiota transplantation (FMT) therapy, the decolonization effect of the experimental group was significantly better than the controls 1 month after treatment (OR: 2.57; 95% CI 1.07-6.16). In studies without a control group and with varying follow-up times, the decolonization rates varied widely but indicated the effectiveness trend of FMT therapy (61.3-81.2%). Currently, research on the decolonization effect of probiotic therapy on ESBL-E/CRE is insufficient, and only a systematic review was conducted. SDD and FMT strategies have short-term benefits for ESBL-E/CRE decolonization, but long-term effects are unclear. The effect of probiotic therapy on ESBL-E/CRE decolonization is an interesting topic that still requires further investigation.

The gut, urine, and vaginal microbiomes play significant roles in the pathogenesis of recurrent urinary tract infections (rUTIs). Analysis of these microbiota has shown distinct associations with urinary tract infections. Encouraging data indicate that rUTIs may be responsive to microbiome treatments such as fecal microbiota transplantation, expanding potential treatments beyond antibiotics, hydration, and behavioral interventions. If successful, these nonantibiotic therapies have the potential to increase time between rUTI episodes and reduce the prevalence of multidrug-resistant organisms. In this review, we discuss the role of the 3 microbiomes in the pathogenesis of rUTI and utilization of live biotherapeutic products as therapy for rUTI.

We evaluated the effect of fecal microbiota transplantation (FMT) on the clearance of carbapenemase-producing Enterobacterales (CPE) carriage.

We performed a prospective, multi-center study, conducted among patients who received a single dose of FMT from one of four healthy donors. The primary endpoint was complete clearance of CPE carriage two weeks after FMT with a secondary endpoint at three months. Shotgun metagenomic sequencing was performed to assess gut microbiota composition of donors and recipients before and after FMT.

Twenty CPE-colonized patients were included in the study, where post-FMT 20% (n = 4/20) of patients met the primary endpoint and 40% (n = 8/20) of patients met the secondary endpoint. Kaplan-Meier curves between patients with FMT intervention and the control group (n = 82) revealed a similar rate of decolonization between groups. Microbiota composition analyses revealed that response to FMT was not donor-dependent. Responders had a significantly lower relative abundance of CPE species pre-FMT than non-responders, and 14 days post-FMT responders had significantly higher bacterial species richness and alpha diversity compared to non-responders (p < 0.05). Responder fecal samples were also enriched in specific species, with significantly higher relative abundances of Faecalibacterium prausnitzii, Parabacteroides distasonis, Collinsella aerofaciens, Alistipes finegoldii and Blautia_A sp900066335 (q<0.01) compared to non-responders.

FMT administration using the proposed regimen did not achieve statistical significance for complete CPE decolonization but was correlated with the relative abundance of specific bacterial taxa, including CPE species.

The human microbiome is a complex network of microorganisms that includes viruses, bacteria, and fungi. The gut virome is an essential component of the immune system, which is responsible for regulating the growth and responses of the host's immune system. The virome maintains a crucial role in the development of numerous diseases, including inflammatory bowel disease (IBD), Crohn's disease, and neurodegenerative disorders. The human virome has emerged as a promising biomarker and therapeutic target. This comprehensive review summarizes the present understanding of the virome and its implications in matters of health and disease, with a focus on the Human Microbiome Project.

There is a surfeit of bioinformatic data showing that bacteriophages abound in the enteric microbiomes of humans. What is the contribution of these viruses in shaping the bacterial strain and species composition of the gut microbiome and how are these phages maintained over time? To address these questions, we performed experiments with Escherichia coli and phages isolated from four fecal microbiota transplantation (FMT) doses as representative samples of non-dysbiotic enteric microbiota and develop and analyze the properties of a mathematical model of the population and evolutionary dynamics of bacteria and phage. Our models predict and experiments confirm that due to production of the O antigen, E. coli in the enteric microbiome are likely to be resistant to infection with co-occurring phages. Furthermore, our modeling suggests that the phages can be maintained in the population due to the high rates of host transition between resistant and sensitive states, which we call leaky resistance. Based on our observations and model predictions, we postulate that the phages found in the human gut are likely to play little role in shaping the composition of E. coli at the strain level in the enteric microbiome in healthy individuals. How general this is for other species of bacteria in the enteric flora is not yet clear, although O antigen expression is common across many taxa.

The eradication regimen for Helicobacter pylori (H. pylori) infection can induce gut dysbiosis. In this open-label, prospective, and randomized clinical trial, we aimed to assess the effects of fucoidan supplementation on the eradication rate and gut microbial homeostasis in the context of quadruple therapy, as well as to investigate the combined effects of fucoidan and synbiotics supplementations.

Eighty patients with H. pylori infection were enrolled and randomly assigned to one of four treatment groups: the QT (a 2-week quadruple therapy alone), QF (quadruple therapy plus a 6-week fucoidan supplementation), QS (quadruple therapy plus a 6-week synbiotics supplementation), and QFS (quadruple therapy with a 6-week fucoidan and synbiotics supplementation), with 20 patients in each group. The QT regimen included rabeprazole, minocycline, amoxicillin, and bismuth potassium citrate. The synbiotics supplementation contained three strains of Bifidobacterium, three strains of Lactobacillus, along with three types of dietary fiber. All of the patients underwent 13C-urea breath test (13C-UBT) at baseline and at the end of the 6th week after the initiation of the interventions. Fresh fecal samples were collected at baseline and at the end of the 6th week for gut microbiota analysis via 16S rRNA gene sequencing.

The eradication rates among the four groups showed no significant difference. In the QT group, a significant reduction in α-diversity of gut microbiota diversity and a substantial shift in microbial composition were observed, particularly an increase in Escherichia-Shigella and a decrease in the abundance of genera from the Lachnospiraceae and Ruminococcaceae families. The Simpson index was significantly higher in the QF group than in the QT group. Neither the QS nor QFS groups exhibited significant changes in α-diversity or β-diversity. The QFS group was the only one that did not show a significant increase in the relative abundance of Escherichia-Shigella, and the relative abundance of Klebsiella significantly decreased in this group.

The current study provided supporting evidence for the positive role of fucoidan and synbiotics supplementation in the gut microbiota. The combined use of fucoidan and synbioticss might be a promising adjuvant regimen to mitigate gut dysbiosis during H. pylori eradication therapy.

Colonisation by bacterial pathogens typically precedes invasive infection and seeds transmission. Thus, effective decolonisation strategies are urgently needed. The literature reports attempts to use phages for decolonisation. To assess the in-vivo efficacy and safety of phages for bacterial decolonisation, we performed a systematic review by identifying relevant studies to assess the in-vivo efficacy and safety of phages for bacterial decolonisation. We searched PubMed, Embase (Ovid), MEDLINE (Ovid), Web of Science, and the Cochrane Library to identify relevant articles published between Jan 1, 1990, and May 12, 2023, without language restrictions. We included studies that assessed the efficacy of phage for bacterial decolonisation in humans or vertebrate animal models. This systematic review is registered with PROSPERO, CRD42023457637. We identified 6694 articles, of which 56 (51 animal studies and five clinical reports) met the predetermined selection criteria and were included in the final analysis. The gastrointestinal tract (n=49, 88%) was the most studied bacterial colonisation site, and other sites were central venous catheters, lung, nose, skin, and urinary tract. Of the 56 included studies, the bacterial load at the colonisation site was reported to decrease significantly in 45 (80%) studies, but only five described eradication of the target bacteria. 15 studies reported the safety of phages for decolonisation. No obvious adverse events were reported in both the short-term and long-term observation period. Given the increasing life-threatening risks posed by bacteria that are difficult to treat, phages could be an alternative option for bacterial decolonisation, although further optimisation is required before their application to meet clinical needs.

Acute graft-versus-host disease (GvHD) is a major and sometimes lethal complication following allogeneic stem cell transplantation (aSCT). In the last 10 years, a massive loss of microbiota diversity with suppression of commensal bacteria and their protective metabolites has been identified as a major risk factor of GvHD.

Since 2018, several studies have been published showing some efficacy of fecal microbiota transfer (FMT) in aSCT patients. FMT was used (1) to eliminate antibiotic resistant bacteria, (2) to restore microbiota diversity after hematopoietic recovery, or (3) in most cases to treat steroid-resistant GvHD. Overall response rates between 30 and 50% have been reported, but randomized trials are still pending. Newer approaches try to evaluate the role of prophylactic FMT in order to prevent GvHD and other complications. Although aSCT patients are heavily immunosuppressed, no major safety concerns regarding FMT have been reported so far.

FMT is a promising approach for modulation of GvHD after aSCT and should be further explored in randomized trials.

The increase of multidrug-resistant (MDR) bacteria in healthcare settings is a worldwide concern. Isolation precautions must be implemented to control the significant risk of transmitting these pathogens among patients. Antibiotic decolonization is not recommended because of the threat of increasing antibiotic resistance. However, restoring gut microflora through faecal microbiota transplantation (FMT) is a hopeful solution.

In 2019-2022, FMT was indicated in seven patients of the Spinal Cord Unit at University Hospital Motol who were colonized with MDR bacterial strains. Five patients tested positive for carriage of carbapenemase-producing Enterobacteriaceae, and two were carriers of vancomycin-resistant enterococci. Isolation measures were implemented in all patients. Donor faeces were obtained from healthy, young, screened volunteers. According to local protocol, 200-300 ml of suspension was applied through a nasoduodenal tube.

The mean age of the patients was 43 years. The mean length of previous hospital stay was 93.2 days. All patients were treated with broad-spectrum antibiotics for infectious complications before detecting colonisation with MDR bacteria. MDR organism decolonization was achieved in five patients, and consequently, isolation measures could be removed. Colonization persisted in two patients, one of whom remained colonized even after a third FMT. No adverse events were reported after FMT.

FMT is a safe and effective strategy to eradicate MDR bacteria, even in spinal cord injured patients. FMT can allow relaxation of isolation facilitates, the participation of patients in a complete rehabilitation program, their social integration, and transfer to follow-up rehabilitation centres.

Multidrug-resistant (MDR) bacteria are a growing global threat, especially in healthcare facilities. Faecal microbiota transplantation (FMT) is an effective prevention strategy for recurrences of Clostridioides difficile infections and can also be useful for other microbiota-related diseases.

We study the effect of FMT in patients with multiple recurrent C. difficile infections on colonisation with MDR bacteria and antibiotic resistance genes (ARG) on the short (3 weeks) and long term (1-3 years), combining culture methods and faecal metagenomics.

Based on MDR culture (n = 87 patients), we notice a decrease of 11.5% in the colonisation rate of MDR bacteria after FMT (20/87 before FMT = 23%, 10/87 3 weeks after FMT). Metagenomic sequencing of patient stool samples (n = 63) shows a reduction in relative abundances of ARGs in faeces, while the number of different resistance genes in patients remained higher compared to stools of their corresponding healthy donors (n = 11). Furthermore, plasmid predictions in metagenomic data indicate that patients harboured increased levels of resistance plasmids, which appear unaffected by FMT. In the long term (n = 22 patients), the recipients' resistomes are still donor-like, suggesting the effect of FMT may last for years.

Taken together, we hypothesise that FMT restores the gut microbiota to a composition that is closer to the composition of healthy donors, and potential pathogens are either lost or decreased to very low abundances. This process, however, does not end in the days following FMT. It may take months for the gut microbiome to re-establish a balanced state. Even though a reservoir of resistance genes remains, a notable part of which on plasmids, FMT decreases the total load of resistance genes.

Infectious diarrhoea is common post-allogeneic haematopoietic stem-cell transplantation (alloHSCT). While the epidemiology of Clostridioides difficile infection (CDI) post-alloHSCT has been described, the impact of other diarrhoeal pathogens is uncertain. We reviewed all alloHSCT between 2017 and 2022 at a single large transplant centre; 374 patients were identified and included. The 1-year incidence of infectious diarrhoea was 23%, divided into viral (13/374, 3%), CDI (65/374, 17%) and other bacterial infections (16/374, 4%). There was a significant association between infectious diarrhoea within 1 year post-transplant and the occurrence of severe acute lower gastrointestinal graft-versus-host disease (GVHD, OR = 4.64, 95% CI 2.57-8.38, p < 0.001) and inferior GVHD-free, relapse-free survival on analysis adjusted for age, donor type, stem cell source and T-cell depletion (aHR = 1.64, 95% CI = 1.18-2.27, p = 0.003). When the classes of infectious diarrhoea were compared to no infection, bacterial (OR = 6.38, 95% CI 1.90-21.40, p = 0.003), CDI (OR = 3.80, 95% CI 1.91-7.53, p < 0.001) and multiple infections (OR = 11.16, 95% CI 2.84-43.92, p < 0.001) were all independently associated with a higher risk of severe GI GVHD. Conversely, viral infections were not (OR = 2.98, 95% CI 0.57-15.43, p = 0.20). Non-viral infectious diarrhoea is significantly associated with the development of GVHD. Research to examine whether the prevention of infectious diarrhoea via infection control measures or modulation of the microbiome reduces the incidence of GVHD is needed.

The human gastrointestinal (gut) microbiome plays a critical role in maintaining host health and has been increasingly recognized as an important factor in precision medicine. High-throughput sequencing technologies have revolutionized -omics data generation, facilitating the characterization of the human gut microbiome with exceptional resolution. The analysis of various -omics data, including metatranscriptomics, metagenomics, glycomics, and metabolomics, holds potential for personalized therapies by revealing information about functional genes, microbial composition, glycans, and metabolites. This multi-omics approach has not only provided insights into the role of the gut microbiome in various diseases but has also facilitated the identification of microbial biomarkers for diagnosis, prognosis, and treatment. Machine learning algorithms have emerged as powerful tools for extracting meaningful insights from complex datasets, and more recently have been applied to metagenomics data via efficiently identifying microbial signatures, predicting disease states, and determining potential therapeutic targets. Despite these rapid advancements, several challenges remain, such as key knowledge gaps, algorithm selection, and bioinformatics software parametrization. In this mini-review, our primary focus is metagenomics, while recognizing that other -omics can enhance our understanding of the functional diversity of organisms and how they interact with the host. We aim to explore the current intersection of multi-omics, precision medicine, and machine learning in advancing our understanding of the gut microbiome. A multidisciplinary approach holds promise for improving patient outcomes in the era of precision medicine, as we unravel the intricate interactions between the microbiome and human health.

In small series, third-party fecal microbiota transplantation (FMT) has been successful in decolonizing the gut from clinically relevant antibiotic resistance genes (ARGs). Less is known about the short- and long-term effects of FMT on larger panels of ARGs. We analyzed 226 pre- and post-treatment stool samples from a randomized placebo-controlled trial of FMT in 100 patients undergoing allogeneic hematopoietic cell transplantation or receiving anti-leukemia induction chemotherapy for 47 ARGs. These patients have heavy antibiotic exposure and a high incidence of colonization with multidrug-resistant organisms. Samples from each patient spanned a period of up to 9 months, allowing us to describe both short- and long-term effects of FMT on ARGs, while the randomized design allowed us to distinguish between spontaneous changes vs. FMT effect. We find an overall bimodal pattern. In the first phase (days to weeks after FMT), low-level transfer of ARGs largely associated with commensal healthy donor microbiota occurs. This phase is followed by long-term resistance to new ARGs as stable communities with colonization resistance are formed after FMT. The clinical implications of these findings are likely context-dependent and require further research. In the setting of cancer and intensive therapy, long-term ARG decolonization could translate into fewer downstream infections.

Faecal/intestinal microbiota transplant (FMT/IMT) is an efficacious treatment option for recurrent Clostridioides difficile infection, which has prompted substantial interest in FMT's potential role in the management of a much broader range of diseases associated with the gut microbiome. Despite its promise, the success rates of FMT in these other settings have been variable. This review critically evaluates the current evidence on the impact of clinical, biological, and procedural factors upon the therapeutic efficacy of FMT, and identifies areas that remain nebulous. Due to some of these factors, the optimal therapeutic approach remains unclear; for example, the preferred timing of FMT administration in a heavily antibiotic-exposed hematopoietic cell transplant recipient is not standardized, with arguments that can be made in alternate directions. We explore how these factors may impact upon more informed selection of donors, potential matching of donors to recipients, and aspects of clinical care of FMT recipients. This includes consideration of how gut microbiome composition and functionality may strategically inform donor selection criteria. Furthermore, we review how the most productive advances within the FMT space are those where clinical and translational outcomes are assessed together, and where this model has been used productively in recent years to better understand the contribution of the gut microbiome to human disease, and start the process toward development of more targeted microbiome therapeutics.

Antibiotics have benefitted human health since their introduction nearly a century ago. However, the rise of antibiotic resistance may portend the dawn of the "post-antibiotic age." With the narrow pipeline for novel antimicrobials, we need new approaches to deal with the rise of multidrug resistant organisms. In the last 2 decades, the role of the intestinal microbiota in human health has been acknowledged and studied widely. Of the various activities carried out by the gut microbiota, colonization resistance is a key function that helps maintain homeostasis. Therefore, re-establishing a healthy microbiota is a novel strategy for treating drug resistance organisms. Preliminary studies suggest that this is a viable approach. However, the extent of their success still needs to be examined. Herein, we will review work in this area and suggest where future studies can further investigate this method for dealing with the threat of antibiotic resistance.

Gut microbiota injury in allogeneic hematopoietic cell transplantation (HCT) recipients and patients with AML has been associated with adverse clinical outcomes. Previous studies in these patients have shown improvements in various microbiome indices after fecal microbiota transplantation (FMT). However, whether microbiome improvements translate into improved clinical outcomes remains unclear. We examined this question in a randomized, double-blind, placebo-controlled phase II trial.

Two independent cohorts of allogeneic HCT recipients and patients with AML receiving induction chemotherapy were randomly assigned in a 2:1 ratio to receive standardized oral encapsulated FMT versus placebo upon neutrophil recovery. After each course of antibacterial antibiotics, patients received a study treatment. Up to three treatments were administered within 3 months. The primary end point was 4-month all-cause infection rate. Patients were followed for 9 months.

In the HCT cohort (74 patients), 4-month infection density was 0.74 and 0.91 events per 100 patient-days in FMT and placebo arms, respectively (infection rate ratio, 0.83; 95% CI, 0.48 to 1.42; P = .49). In the AML cohort (26 patients), 4-month infection density was 0.93 in the FMT arm and 1.25 in the placebo arm, with an infection rate ratio of 0.74 (95% CI, 0.32 to 1.71; P = .48). Unique donor bacterial sequences comprised 25%-30% of the fecal microbiota after FMT. FMT improved postantibiotic recovery of microbiota diversity, restored several depleted obligate anaerobic commensals, and reduced the abundance of expanded genera Enterococcus, Streptococcus, Veillonella, and Dialister.

In allogeneic HCT recipients and patients with AML, third-party FMT was safe and ameliorated intestinal dysbiosis, but did not decrease infections. Novel findings from this trial will inform future development of FMT trials.

The gut microbiota plays a crucial role in the human microenvironment. Dysbiosis of the gut microbiota is a common pathophysiological phenomenon in critically ill patients. Therefore, utilizing intestinal microbiota to prevent complications and improve the prognosis of critically ill patients is a possible therapeutic direction. The gut microbiome-based therapeutics approach focuses on improving intestinal microbiota homeostasis by modulating its diversity, or treating critical illness by altering the metabolites of intestinal microbiota. There is growing evidence that fecal microbiota transplantation (FMT), selective digestive decontamination (SDD), and microbiota-derived therapies are all effective treatments for critical illness. However, different treatments are appropriate for different conditions, and more evidence is needed to support the selection of optimal gut microbiota-related treatments for different diseases. This narrative review summarizes the curative effects and limitations of microbiome-based therapeutics in different critically ill adult patients, aiming to provide possible directions for gut microbiome-based therapeutics for critically ill patients such as ventilator-associated pneumonia, sepsis, acute respiratory distress syndrome, and COVID-19, etc.

The gut is host to a diverse array of microbiota that constitute a complex ecological system crucial to human physiology. Disruptors to the normal host microbiota, such as antimicrobials, can cause a loss of species diversity in the gut, reducing its ability to resist colonization by invading pathogens and potentially leading to colonization with antimicrobial resistant organisms (AROs). ARO negatively impact gut health by disrupting the usual heterogeneity of gut microbiota and have the potential to cause systemic disease. In recent years, fecal microbiota transplantation (FMT) has been increasingly explored in the management of specific disease states such as Clostridioides difficile infection (CDI). Promising data from management of CDI has led to considerable interest in understanding the role of therapeutics to restore the gut microbiota to a healthy state. This review aims to discuss key studies that highlight the current landscape, and explore existing clinical evidence, for the use of FMT and microbiome-based therapeutics in combating intestinal colonization with ARO. We also explore potential future directions of such therapeutics and discuss unaddressed needs in this field that merit further investigation.

Faecal microbiota transplantation (FMT) is recommended treatment for recurrent Clostridioides difficile infection and is studied as a potential modifier of other gastrointestinal and systemic disorders. Autologous FMT limits the potential risks of donor transplant material and enables prophylactic treatment. Capsulized FMT is convenient and accessible, but safety data are lacking.

To describe safety and tolerability of capsules containing autologous FMT, compared to placebo, in healthy volunteers treated with antibiotics.

Healthy volunteers without antibiotic exposure during the past three months, that had a negative Clostridioides difficile stool sample, were recruited. Study persons donated faeces for production of capsules containing autologous microbiota. They were then given Clindamycin for seven days to disrupt the intestinal microbiota, which was followed by a two-day washout. Study persons were then randomized (1:1) to unsupervised treatment with autologous faecal matter or placebo, with two capsules twice daily for five days. A standardized questionnaire about side effects and tolerability, daily until day 28, and on days 60 and 180, was completed.

Twenty-four study persons were included, all completed the treatment. One person from the placebo and FMT groups each, were lost to follow up from days 21 and 60, respectively. No study person experienced serious side effects, but severe fatigue was reported during the antibiotic period (n = 2). Reported side effects were mild to moderate and there were no significant differences between the groups. Reported general and intestinal health improved significantly and similarly in both groups after the antibiotic treatment. Time to normalized intestinal habits were 17 and 19 days from study start in the placebo group and the FMT group, respectively (p = 0.8).

Capsulized frozen autologous faecal microbiota transplantation was safe and well tolerated but did not affect time to normalized intestinal habits compared to placebo.

EudraCT 2017-002418-30.

Microbiota changes during allogeneic hematopoietic stem cell transplantation has several known causes: conditioning chemotherapy and radiation, broad-spectrum antibiotic administration, modification in nutrition status and diet, and graft-versus-host disease. This article aims to review the current knowledge about the close link between microbiota and allogeneic stem cell transplantation setting. The PubMed search engine was used to perform this review. We analyzed data on microbiota dysbiosis related to the above-mentioned affecting factors. We also looked at treatments aimed at modifying gut dysbiosis and applications of fecal microbiota transplantation in the allogeneic stem cell transplant field, with particular interest in fecal microbiota transplantation for graft-versus-host disease (GvHD), multidrug-resistant and clostridium difficile infections, and microbiota restoration after chemotherapy and antibiotic therapy.

Critically ill patients have a hyper-inflammatory response against various offending injuries that can result in tissue damage, organ failure, and fatal prognosis. The origin of this detrimental, uncontrolled inflammatory cascade can be found also within our gut. In detail, one of the main actors is our gut microbiota with its imbalance, namely gut dysbiosis: learning about the microbiota's dysfunction and pathophysiology in the frame of critical patients is of crucial and emerging importance in the management of the systemic inflammatory response syndrome (SIRS) and the multiple organ dysfunction syndrome (MODS). Multiple pieces of evidence indicate that the bacteria that populate our gut efficiently modulate the immune response. Treatment and pretreatment with probiotics have shown promising preliminary results to attenuate systemic inflammation, especially in postoperative infections and ventilation performance. Finally, it is emerging how immunonutrition may exert a possible impact on the health status of patients in intensive care. Thus, this manuscript reviews evidence from the literature on gut microbiota composition, its derangement in critically ill patients, its pathophysiological role, and the described and emerging opportunities arising from its modulation.

Haematopoietic stem cell transplantation (HSCT) is a treatment option for many haematological conditions in patients of all ages. Nutritional support is important at each stage of treatment, but particular nutritional needs and dictated support occur during the preparatory (conditioning regimen) and post-transplant periods. Patients may require nutritional treatment by the enteral or parenteral route. The quantitative and qualitative composition of meals may change. Vitamin requirements, including vitamin D and vitamin C, might also be different. An adequately composed diet, adapted to the needs of the patient, may influence the occurrence of complications such as graft-versus-host disease (GvHD), gastrointestinal disorders, infections, and reduced survival time. Haematological diseases as well as transplantation can negatively affect the intestinal flora, with negative consequences in the form of mucosal inflammation and disorders of a functional nature. Currently, aspects related to nutrition are crucial in the care of patients after HSCT, and numerous studies, including randomized trials on these aspects, are being conducted. This study serves the critical analysis of current scientific evidence regarding nutritional support for patients after HSCT.

Since its first appearance in late 2019 in Wuhan, China, severe acute respiratory syndrome caused by Coronavirus 2 (SARS-CoV-2) has had a major impact on healthcare facilities around the world. Although in the past year, mass vaccination and the development of monoclonal antibody treatments have reduced the number of deaths and severe cases, the circulation of SARS-CoV-2 remains high. Over the past two years, diagnostics have played a crucial role in virus containment both in health care facilities and at the community level. For SARS-CoV-2 detection, the commonly used specimen type is the nasopharyngeal swab, although the virus can be identified in other matrices such as feces. Since fecal microbiota transplantation (FMT) assumes significant importance in the treatment of chronic gut infections and that feces may be a potential vehicle for transmission of SARS-CoV-2, in this study we have evaluated the performance of the rapid cartridge-based RT-PCR test STANDARD™ M10 SARS-CoV-2 (SD Biosensor Inc., Suwon, South Korea) using fecal samples. The results obtained indicates that STANDARD™ M10 SARS-CoV-2 can detect SARS-CoV-2 in stool samples even at low concentration. For this reason, STANDARD™ M10 SARS-CoV-2 could be used as reliable methods for the detection of SARS-CoV-2 in fecal samples and for the screening of FMT donors.

Antimicrobial resistance (AMR) is one of the greatest challenges facing humanity, causing a substantial burden to the global healthcare system. AMR in Gram-negative organisms is particularly concerning due to a dramatic rise in infections caused by extended-spectrum beta-lactamase and carbapenemase-producing Enterobacterales (ESBL and CPE). These pathogens have limited treatment options and are associated with poor clinical outcomes, including high mortality rates. The microbiota of the gastrointestinal tract acts as a major reservoir of antibiotic resistance genes (the resistome), and the environment facilitates intra and inter-species transfer of mobile genetic elements carrying these resistance genes. As colonisation often precedes infection, strategies to manipulate the resistome to limit endogenous infections with AMR organisms, as well as prevent transmission to others, is a worthwhile pursuit. This narrative review presents existing evidence on how manipulation of the gut microbiota can be exploited to therapeutically restore colonisation resistance using a number of methods, including diet, probiotics, bacteriophages and faecal microbiota transplantation (FMT).

During the ongoing biodiversity crisis, captive conservation and breeding programs offer a refuge for species to persist and provide source populations for reintroduction efforts. Unfortunately, captive animals are at a higher disease risk and reintroduction efforts remain largely unsuccessful. One potential factor in these outcomes is the host microbiota which includes a large diversity and abundance of bacteria, fungi, and viruses that play an essential role in host physiology. Relative to wild populations, the generalized pattern of gut and skin microbiomes in captivity are reduced alpha diversity and they exhibit a significant shift in community composition and/or structure which often correlates with various physiological maladies. Many conditions of captivity (antibiotic exposure, altered diet composition, homogenous environment, increased stress, and altered intraspecific interactions) likely lead to changes in the host-associated microbiome. To minimize the problems arising from captivity, efforts can be taken to manipulate microbial diversity and composition to be comparable with wild populations through methods such as increasing dietary diversity, exposure to natural environmental reservoirs, or probiotics. For individuals destined for reintroduction, these strategies can prime the microbiota to buffer against novel pathogens and changes in diet and improve reintroduction success. The microbiome is a critical component of animal physiology and its role in species conservation should be expanded and included in the repertoire of future management practices.

Sepsis is the leading cause of death in critically ill patients. The gastrointestinal tract has long been thought to play an important role in the pathophysiology of sepsis. Antibiotic therapy can reduce a patient's commensal bacterial population and raise their risk of developing subsequent illnesses, where gut microbiota dysbiosis may be a key factor.

In this study, we analyzed the 16S rRNA of fecal samples from both healthy people and patients with sepsis to determine if alterations in gut bacteria are associated with sepsis. Then, we developed a mouse model of sepsis using cecal ligation and puncture (CLP) in order to examine the effects of fecal microbiota transplantation (FMT) and short-chain fatty acids (SCFAs) on survival rate, systemic inflammatory response, gut microbiota, and mucosal barrier function.

Sepsis patients' gut microbiota composition significantly differed from that of healthy people. At the phylum level, the amount of Proteobacteria in the intestinal flora of sepsis patients was much larger than that of the control group, whereas the number of Firmicutes was significantly lower. Mice with gut microbiota disorders (ANC group) were found to have an elevated risk of death, inflammation, and organ failure as compared to CLP mice. However, all of these could be reversed by FMT and SCFAs. FMT and SCFAs could regulate the abundance of bacteria such as Firmicutes, Proteobacteria, Escherichia Shigella, and Lactobacillus, restoring them to levels comparable to those of healthy mice. In addition, they increased the expression of the Occludin protein in the colon of mice with sepsis, downregulated the expression of the NLRP3 and GSDMD-N proteins, and reduced the release of the inflammatory factors IL-1β and IL-18 to inhibit cell pyroptosis, ultimately playing a protective role in sepsis.

FMT and SCFAs provide a microbe-related survival benefit in a mouse model of sepsis, suggesting that they may be a viable treatment for sepsis.

The increasing prevalence of multidrug-resistant organism (MDRO) carriage poses major challenges to medicine as healthcare costs increase. Recently, faecal microbiota transplantation (FMT) has been discussed as a novel and effective method for decolonizing MDRO.

To compare the efficacy of different FMT methods to optimize the success rate of decolonization in patients with MDRO carriage.

This prospective cohort study enrolled patients with MDRO carriages from 2018 to 2021. Patients underwent FMT via one of the following methods: oral capsule, oesophagogastroduodenoscopy (EGD), colonoscopy, or gastric tube.

A total of 57 patients underwent FMT for MDRO decolonization. The colonoscopy group required the shortest time for decolonization, whereas the EGD group required the longest (24.9 vs 190.4 days, P = 0.022). The decolonization rate in the oral capsule group was comparable to that in the EGD group (84.6% vs 85.7%, P = 0.730). An important clinical factor associated with decolonization failure was antibiotic use after FMT (odds ratio = 6.810, P = 0.008). All four groups showed reduced proportions of MDRO species in microbiome analysis after FMT.

Compared to other conventional methods, the oral capsule is an effective FMT method for patients who can tolerate an oral diet. The discontinuation of antibiotics after FMT is a key factor in the success of decolonization.

This article evaluates the efficacy and safety of FMT in the treatment of GVHD after HSCT using a systematic literature search to conduct a meta-analysis constructed of studies involving GVHD patients treated with FMT. 23 studies were included, among which 2 prospective cohort studies, 10 prospective single arm studies, 2 retrospective single arm studies, 2 case series and 7 case reports, comprise a total of 242 patients with steroid-resistant or steroid-dependent GVHD secondary to HSCT who were treated with FMT. 100 cases achieved complete responses, while 61 cases showed partial responses, and 81 cases presented no effect after FMT treatment. The estimate of clinical remission odds ratio was 5.51 (95% CI 1.49-20.35) in cohort studies, and the pooled clinical remission rate is 64% (51-77%) in prospective single arm studies and 81% (62-95%) in retrospective studies, case series and case reports. Five (2.1%) patients had FMT-related infection events, but all recovered after treatment. Other adverse effects were mild and acceptable. Microbiota diversity and composition, donor type, and other related issues were also analyzed. The data proves that FMT is a promising treatment modality of GVHD, but further validation of its safety and efficacy is still needed with prospective control studies.Clinical trial registration: Registered in https://www.crd.york.ac.uk/PROSPERO/ CRD42022296288.