A microbial consortium alters intestinal Pseudomonadota and antimicrobial resistance genes in individuals with recurrent Clostridioides difficile infection

Leveraging strain competition to address antimicrobial resistance with microbiota therapies

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.

Harnessing the human gut microbiota: an emerging frontier in combatting multidrug-resistant bacteria

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.

Multiomics comparative analysis of feces AMRGs of Duroc pigs and Tibetan and the effect of fecal microbiota transplantation on AMRGs upon antibiotic exposure

Fecal matter is recognized as both a reservoir and a transmission source for various antimicrobial resistance genes (AMRGs). However, the transcriptional activity of AMRGs in swine feces is not well understood. In addition, the effect of fecal microbiota transplantation (FMT) on the excretion of AMRGs has rarely been reported. Our study explored the diversity, abundance, transcriptional activity, and bacterial hosts of AMRGs in Tibetan and Duroc pig feces using metagenomic and metatranscriptomic sequencing technologies. We discovered a significantly higher genomic abundance of AMRGs in the feces of Duroc pigs compared to Tibetan pigs (P < 0.001), although the transcript levels did not show a significant difference. The results showed that the core composition of AMRGs in pig feces varied considerably, with the most transcriptionally active AMRGs being oqxB, tetQ, Bla1, dfrA1, and amrB. Furthermore, the Firmicutes phylum is the main host of AMRGs. By transplanting fecal flora from Tibetan and Duroc pigs into the intestines of Duroc Landrace Yorkshire (DLY) piglets after acute antibiotic exposure, we found that only Tibetan pig fecal flora significantly reduced AMRGs in the feces of DLY piglets (P < 0.05). The effectiveness of Tibetan pig fecal microorganisms in removing AMRGs from DLY pig feces was mainly influenced by microbial communities, especially the Bacteroidota phylum. These findings offer valuable insights for the prevention and control of AMRG pollution.

IMPORTANCE

To the best of our knowledge, this study represents the first comprehensive analysis of antimicrobial resistance gene (AMRGs) expression in the fecal microbiota of Tibetan and Duroc pigs, employing an integrated metagenomic and metatranscriptomic approach. Our findings indicate a higher risk of AMRGs transmission in the feces of Duroc pigs compared to Tibetan pigs. Given the escalating antimicrobial resistance crisis, novel therapeutic interventions are imperative to mitigate gut colonization by pathogens and AMRGs. In this regard, we investigated the impact of fecal microbiota from Tibetan and Duroc pig sources on AMRGs excretion in Duroc Landrace Yorkshire (DLY) piglets' feces following acute antibiotic exposure. Remarkably, only fecal microbiota sourced from Tibetan pigs exhibited a reduction in AMRGs excretion in DLY piglets' feces. This underscores the significance of evaluating the presence of AMRGs within donor fecal microbiota for effective AMRGs decolonization strategies.

Prospective manipulation of the gut microbiome with microbial ecosystem therapeutic 4 (MET4) in HPV-related locoregionally-advanced oropharyngeal cancer squamous cell carcinoma (LA-OPSCC) undergoing primary chemoradiation: ROMA2 study

BACKGROUND

Gut microbiome modulation to boost antitumor immune responses is under investigation.

METHODS

ROMA-2 evaluated the microbial ecosystem therapeutic (MET)-4 oral consortia, a mixture of cultured human stool-derived immune-responsiveness associated bacteria, given with chemoradiation (CRT) in HPV-related oropharyngeal cancer patients. Co-primary endpoints were safety and changes in stool cumulative MET-4 taxa relative abundance (RA) by 16SRNA sequencing. Stools and plasma were collected pre/post-MET-4 intervention for microbiome and metabolome analysis.

RESULTS

Twenty-nine patients received ≥1 dose of MET-4 and were evaluable for safety: drug-related adverse events (AEs) occurred in 13/29 patients: all grade 1-2 except one grade 3 (diarrhea). MET-4 was discontinued early in 7/29 patients due to CRT-induced toxicity, and in 1/29 due to MET-4 AEs. Twenty patients were evaluable for ecological endpoints: there was no increase in stool MET-4 RA post-intervention but trended to increase in stage III patients (p = 0.06). MET-4 RA was higher in stage III vs I-II patients at week 4 (p = 0.03) and 2-month follow-up (p = 0.01), which correlated with changes in plasma and stool targeted metabolomics.

CONCLUSIONS

ROMA-2 did not meet its primary ecologic endpoint, as no engraftment was observed in the overall cohort. Exploratory findings of engraftment in stage III patients warrants further investigation of microbiome interventions in this subgroup.

The Relationship Between the Microbiome and Antimicrobial Resistance

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.