Oral Administration of the Antimicrobial Peptide Mastoparan X Alleviates Enterohemorrhagic Escherichia coli-Induced Intestinal Inflammation and Regulates the Gut Microbiota

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.

Engineered Bacillus subtilis WB600/ZD prevents Salmonella Infantis-induced intestinal inflammation and alters the colon microbiota in a mouse model

Antimicrobial peptides (AMPs) are instrumental in maintaining intestinal homeostasis and have emerged as potential therapeutic candidates for ameliorating intestinal bacterial infections. However, the intrinsic instability associated with the in vivo delivery of AMPs constitutes a substantial impediment to their therapeutic efficacy in treating infections. In this study, we genetically modified Bacillus subtilis (B. subtilis) WB600 to express Zophobas atratus defensin (ZD), an antimicrobial peptide with broad-spectrum activity isolated from Zophobas atratus, for oral administration. This engineered strain effectively protects against Salmonella Infantis (S. Infantis) infection in mice. Pretreatment with WB600/ZD prevented NF-κB pathway activation induced by S. Infantis infection and increased expression of antioxidant and tight junction proteins, thus alleviating the severity of intestinal inflammation in both the jejunum and ileum (P < 0.01). Moreover, WB600/ZD pretreatment facilitated the growth of beneficial bacteria such as Lachnospiraceae, Butyricicoccus, Eubacterium_xylanophilum, and Clostridia_UCG-014 while decreasing the abundance of pathogenic bacteria such as Escherichia-Shigella and Salmonella (P < 0.05). In conclusion, this study underscores the protective effects of WB600/ZD on S. Infantis-induced intestinal inflammation, suggesting that oral delivery of B. subtilis WB600/ZD may be a promising prophylactic strategy for combating bacterial infections in the intestine.

Effects of Scallop Mantle Toxin on Intestinal Microflora and Intestinal Barrier Function in Mice

Previous studies have shown that feeding mice with food containing mantle tissue from Japanese scallops results in aggravated liver and kidney damage, ultimately resulting in mortality within weeks. The aim of this study is to evaluate the toxicity of scallop mantle in China's coastal areas and explore the impact of scallop mantle toxins (SMT) on intestinal barrier integrity and gut microbiota in mice. The Illumina MiSeq sequencing of V3-V4 hypervariable regions of 16S ribosomal RNA was employed to study the alterations in gut microbiota in the feces of SMT mice. The results showed that intestinal flora abundance and diversity in the SMT group were decreased. Compared with the control group, significant increases were observed in serum indexes related to liver, intestine, inflammation, and kidney functions among SMT-exposed mice. Accompanied by varying degrees of tissue damage observed within these organs, the beneficial bacteria of Muribaculaceae and Marinifilaceae significantly reduced, while the harmful bacteria of Enterobacteriaceae and Helicobacter were significantly increased. Taken together, this article elucidates the inflammation and glucose metabolism disorder caused by scallop mantle toxin in mice from the angle of gut microbiota and metabolism. SMT can destroy the equilibrium of intestinal flora and damage the intestinal mucosal barrier, which leads to glucose metabolism disorder and intestinal dysfunction and may ultimately bring about systemic toxicity.

Multifunctional role of oral bacteria in the progression of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of liver disorders of varying severity, ultimately leading to fibrosis. This spectrum primarily consists of NAFL and non-alcoholic steatohepatitis. The pathogenesis of NAFLD is closely associated with disturbances in the gut microbiota and impairment of the intestinal barrier. Non-gut commensal flora, particularly bacteria, play a pivotal role in the progression of NAFLD. Notably, Porphyromonas gingivalis, a principal bacterium involved in periodontitis, is known to facilitate lipid accumulation, augment immune responses, and induce insulin resistance, thereby exacerbating fibrosis in cases of periodontitis-associated NAFLD. The influence of oral microbiota on NAFLD via the "oral-gut-liver" axis is gaining recognition, offering a novel perspective for NAFLD management through microbial imbalance correction. This review endeavors to encapsulate the intricate roles of oral bacteria in NAFLD and explore underlying mechanisms, emphasizing microbial control strategies as a viable therapeutic avenue for NAFLD.