Probiotics and Antimicrobial Proteins最新文献

Novel antibiotic substitutes are increasingly in demand in the animal husbandry industry. An oral recombinant Lactococcus lactis (L. lactis) expressing human LL-37 (oral LL-37) was developed and its safety and antiviral effectiveness in vivo was tested. In addition to impairing liposome integrity, LL-37 polypeptide from recombinant L. lactis could prevent the host cell infection by a variety of viruses, including recombinant SARS, SARS-CoV-2, Ebola virus, and vesicular stomatitis virus G. Subchronic toxicity studies performed on Sprague-Dawley rats showed that no cumulative toxicity was found during short-term intervention. Oral LL-37 treatment after the onset of fever could reduce mortality in piglets infected with porcine reproductive and respiratory syndrome virus. Moreover, body weight gain of piglets receiving treatment was progressively restored, and nucleic acid positive rebound was not undetected after discontinuation. Oral LL-37 consistently increased the lifespan of chickens infected with Newcastle viruses. These findings suggested a potential use of recombinantly modified microorganisms in veterinary medicine.

The gut microbiota is the largest and most complex ecosystem consisting of trillions of microorganisms, which influenced by various external factors. As an important probiotic species, Lactobacillus helps to improve gut microbial diversity and composition, underlying potential efficacy in growth performance and disease prevention. However, limited studies have been investigated the relationship between Lactobacillus sakei and intestinal health in dogs. In this study, dogs in the two groups were fed a standard diet (group C, n = 8) and Lactobacillus sakei diet (group P, n = 8), respectively. The growth performance, serum biochemical indices, antioxidant capacity, gut microbiota, and metabolism of dogs in both groups were studied. Results from growth trials showed that L. sakei can significantly improve the growth performance of dogs, including increased weight gain (p < 0.05), serum biochemical indices, i.e., ALP, TP, and ALB (p < 0.05), and better antioxidant capacity, i.e., SOD and GSH-Px (p < 0.05). Significant changes in the gut microbial composition were detected in dogs fed Lactobacillus sakei, as evidenced by an increase in the level of Firmicutes, Spirochaetota, and Patescibacteria, all of them play an important role in maintaining intestinal health. Moreover, a decrease in the level of microorganisms that threaten health, such as Mucispirillum and Clostridium_sensu_stricto_13. The metabolic analysis showed that the Lactobacillus sakei enhanced metabolic pathways such as vitamin B6 metabolism, glutathione metabolism, retinol metabolism, and fatty acid degradation. Our findings suggested that Lactobacillus sakei supplementation had beneficial effects on the growth performance and health status of dogs by improving gut microbiota balance and promoting metabolism. There are an estimated 200 million dogs in China, and the population is continuing to grow at a rapid pace. It is essential to explore an effective way to promote health in dogs. Intestinal diseases, particularly colitis and diarrhea, are common clinical conditions in dogs and are associated with gut microbiota. Lactobacillus sakei, as an important species of probiotics, the relationship between L. sakei and intestinal health in dogs remains unclear. Our study suggests that L. sakei significantly promotes growth performance and health states involving weight gain, regulation of gut microbiota, and metabolism. Overall, our findings shed light on the potential role of L. sakei as an alternative in promoting health in dogs.

Probiotics play a significant role in enhancing health, and they are well known for bacteriocins production. Evaluating probiotics' whole-genome sequence provides insights into their consumption outcomes. Thus, genomic studies have a significant role in assessing the safety of probiotics more in-depth and offer valuable information regarding probiotics' functional diversity, metabolic pathways, and health-promoting mechanisms. Marine Pediococcus pentosaceus E3, isolated from shrimp gut, exhibited beneficial properties, indicating its potential as a probiotic candidate. Phenotypically, E3 strain was susceptible to most antibiotics assessed, tolerant to low pH and high bile salt conditions, and revealed no hemolysin activity. Interestingly, E3-neutralized CFS revealed significant antibacterial activity against pathogens under investigation. Therefore, the concentrated CFS was prepared and evaluated as a natural biopreservative and showed outstanding antimicrobial activity. Furthermore, integrated-based genome assessment has provided insight into probiotic characteristics at the genomic level. Whole-genome sequencing analysis revealed that the E3 genome possesses 1805 protein-coding genes, and the genome size was about 1.8 Mb with a G + C content of 37.28%. Moreover, the genome revealed the absence of virulence factors and clinically related antibiotic genes. Moreover, several genes consistent with probiotic microorganisms' features were estimated in the genome, including stress response, carbohydrate metabolism, and vitamin biosynthesis. In addition, several genes associated with survival and colonization within the gastrointestinal tract were also detected across the E3 genome. Therefore, the findings suggest that insights into the genetic characteristics of E3 guarantee the safety of the strain and facilitate future development of E3 isolate as a health-promoting probiotic and source of biopreservative.

Cancer remains a global problem, with millions of new cases diagnosed yearly and countless lives lost. The financial burden of cancer therapy, along with worries about the long-term safety of existing medicines, necessitates the investigation of alternative approaches to cancer prevention. Probiotics generate chemopreventive compounds such as bacteriocins, short-chain fatty acids (SCFA), and extracellular polymeric substances (EPS), which have demonstrated the ability to impede cancer cell proliferation, induce apoptosis, and bolster the expression of pro-apoptotic genes. On the other hand, prebiotics, classified as non-digestible food ingredients, promote the proliferation of probiotics within the colon, thereby ensuring sustained functionality of the gut microbiota. Consequently, the synergistic effect of combining prebiotics with probiotics, known as the synbiotic effect, in dietary interventions holds promise for potentially mitigating cancer risk and augmenting preventive measures. The utilization of gut microbiota in cancer treatment has shown promise in alleviating adverse health effects. This review explored the potential and the role of probiotics and synbiotics in enhancing health and contributing to cancer prevention efforts. In this review, the applications of functional probiotics and synbiotics, the mechanisms of action of probiotics in cancer, and the relationship of probiotics with various drugs were discussed, shedding light on the potential of probiotics and synbiotics to alleviate the burdens of cancer treatment.

Probiotics, particularly yeasts from the genus Saccharomyces, are valuable for their health benefits and potential as antibiotic alternatives. To be effective, these microorganisms must withstand harsh environmental conditions, necessitating advanced protective technologies such as encapsulation to maintain probiotic viability during processing, storage, and passage through the digestive system. This review and meta-analysis aims to describe and compare methods and agents used for encapsulating Saccharomyces spp., examining operating conditions, yeast origins, and species. It provides an overview of the literature on the health benefits of nutritional yeast consumption. A bibliographic survey was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. The meta-analysis compared encapsulation methods regarding their viability after encapsulation and exposure to the gastrointestinal tract. Nineteen studies were selected after applying inclusion/exclusion criteria. Freeze drying was found to be the most efficient for cell survival, while ionic gelation was best for maintaining viability after exposure to the gastrointestinal tract. Consequently, the combination of freeze drying and ionic gelation proved most effective in maintaining high cell viability during encapsulation, storage, and consumption. Research on probiotics for human food and animal feed indicates that combining freeze drying and ionic gelation effectively protects Saccharomyces spp.; however, industrial scalability must be considered. Reports on yeast encapsulation using agro-industrial residues as encapsulants offer promising strategies for preserving potential probiotic yeasts, contributing to the environmental sustainability of industrial processes.

Urinary tract infections (UTIs) pose a substantial healthcare challenge, exacerbated by the biofilm-forming abilities and antibiotic resistance of uropathogens. This study investigated the inhibition of biofilm formation (anti-biofilm) and dispersion of pre-established biofilm properties of 18 heat-killed probiotics and their supernatants against four antibiotic-resistant uropathogens: UPEC, Klebsiella pneumoniae (KP), Methicillin-resistant Escherichia coli (MREC), and Methicillin-resistant Staphylococcus pseudintermedius (MRSP). Supernatants from 14 probiotic strains significantly (P < 0.001) inhibited UPEC biofilm formation, reducing it by 20-80%, and also showed promise in removing existing biofilms by 10-60% (P < 0.001). Eight strains significantly (P < 0.05 to < 0.001) inhibited MREC biofilm formation, with four strains achieving 50-80% dispersion. Seventeen strains of heat-killed probiotics directly inhibited UPEC biofilm formation by 10-60% (P < 0.05 to < 0.001), but were less effective against MREC and MRSP (10-50% reduction; P < 0.05 to < 0.001) and had limited impact on KP (10% reduction; P < 0.05 to < 0.001). Notably, heat-killed probiotic like LGA, LGC, LGD, TP-8, and TP-4 showed the most significant inhibitory and dispersion of biofilm activity. RT-qPCR analysis further revealed these inactivated probiotics downregulated genes associated with pili and biofilm formation (fimA, csgA) and upregulated genes linked to quorum sensing (luxS, qseBC, sdiA). Therefore, these findings suggest that paraprobiotic treatment could inhibit the formation of pili and biofilms and promote biofilm dispersion. In an animal model, mice given paraprobiotic formulations I (16 strains) and II (a specific mixture) for 2 weeks showed reduced urinary bacterial load (P < 0.05). Paraprobiotic I notably reduced morbidity from bacteriuria (> 10⁵ CFU/ml) by 5 to 30% within the first 5 days post-infection compared to placebo. These findings highlight the potential of specific heat-killed probiotics in combating biofilms and preventing UTIs.

In this study, four lactic acid bacteria (LAB) strains demonstrating ciprofloxacin, bile salt, gastric fluid, and intestinal fluid tolerance as well as adhesion ability to Caco-2 and HT-29 cells were used to improve and recover the intestinal flora disorders caused by ciprofloxacin, among which, Lactobacillus brevis 505 exhibited excellent adhesion ability to two kinds of cells and colonization ability to mouse intestinal. After ciprofloxacin treatment, certain recovery effect on cecum caused by ciprofloxacin in the mice was found during natural recovery (group 5C2), but it was challenging to fully restore the intestinal integrity to the initial level. After L. brevis 505 intervention (group 5C5), the intestinal damage to the colon and ileum caused by ciprofloxacin in mice was significantly alleviated; the recovery effect was better than that of natural recovery. Additionally, L. brevis 505 could effectively regulate INF-γ, sIgA, and RegIIIγ increase induced by ciprofloxacin. Shannon and Simpson index of the intestinal flora of mice in 5C5 group were higher than those in other group, the relative abundance of Bifidobacterium and Lactobacillus in the mice in 5C5 group was increased, indicating that LAB can better restore the structure and abundance of intestinal microflora. Consequently, L. brevis 505 shows promise as a probiotic for gut microbiota restoration and rebuilding during antibiotic therapy.

In the present study, twenty-seven (27) lactobacilli strains, isolated from the vagina of healthy Italian women of reproductive age, were screened for probiotic properties. The strains were evaluated for antagonistic activity against pathogens, adhesion abilities, and potential to displace and/or inhibit the adhesion of previously adhered pathogens as a primary strain selection criterion. Overall, all the tested lactobacilli inhibited at least three pathogens, and the majority of them exhibited antimicrobial activity against Enterobacter cloacae DSM 30054, Pseudomonas aeruginosa DSM 3227, and Pseudomonas aeruginosa DSM 1117. The complete neutralization of antimicrobial activity after cell-free supernatant (CFS) neutralization suggested a pivotal role for lactic acid or other organic acids secreted by the lactobacilli. The strains showed variability in their adhesion levels, but all tested strains adhered to both human colonic epithelial cells (HT-29) and vaginal cells (VK2/E6E7) with adhesion percentages exceeding 1%. The ability to displace or inhibit pathogens was dependent on the pathogen and the lactobacilli strain; the pathogen displacement levels ranged from 9 to 82%, while pathogen exclusion levels varied from 1 to 99%. In conclusion, this study demonstrates the protective effect of vaginal lactobacilli against pathogens and confirms the suitability of the vaginal microbiota as a source of potential probiotic strains. The selected lactobacilli hold promise for the formulation of supplements to enhance genitourinary tract health.

Candida albicans (C. albicans) is the primary etiologic agent of vaginal candidiasis. Lactobacillus species are predominant in the vaginal microbiome; they inhibit the development of vaginal candidiasis by producing antimicrobial agents, such as lactic acid and hydrogen peroxide. In this study, we investigated the effects of Limosilactobacillus fermentum (L. fermentum) KBL674 in a mouse model of vaginal candidiasis. L. fermentum KBL674 inhibited C. albicans hyphal growth. Moreover, oral administration of L. fermentum KBL674 significantly suppressed vaginal C. albicans infection and associated symptoms, including tissue thickness and immune cell infiltration. A substantial quantity of L. fermentum KBL674 was excreted by the mice within 6 h after oral administration, indicating that most L. fermentum KBL674 did not settle within the gastrointestinal tract. L. fermentum KBL674 modulated gut microbiome diversity, increasing abundances of the genera Akkermansia, Eubacterium, and Faecalibaculum and family Muribaculaceae. Abundances of these bacteria showed negative correlations with the vaginal C. albicans burden in the mouse model, suggesting links between the gut microbiome composition and the vaginal C. albicans burden. Therefore, L. fermentum KBL674 can reduce the vaginal C. albicans burden via direct or indirect inhibition and modulation of the gut microbiome composition preventively.

The occurrence and spread of antimicrobial resistance (AMR) pose a looming threat to human health around the world. Novel antibiotics are urgently needed to address the AMR crisis. In recent years, antimicrobial peptides (AMPs) have gained increasing attention as potential alternatives to conventional antibiotics due to their abundant sources, structural diversity, broad-spectrum antimicrobial activity, and ease of production. Given its significance, there has been a tremendous advancement in the research and development of AMPs. Numerous AMPs have been identified from various natural sources (e.g., plant, animal, human, microorganism) based on either well-established isolation or bioinformatic pipelines. Moreover, computer-assisted strategies (e.g., machine learning (ML) and deep learning (DL)) have emerged as a powerful and promising technology for the accurate prediction and design of new AMPs. It may overcome some of the shortcomings of traditional antibiotic discovery and contribute to the rapid development and translation of AMPs. In these cases, this review aims to appraise the latest advances in identifying and designing AMPs and their significant antimicrobial activities against a wide range of bacterial pathogens. The review also highlights the critical challenges in discovering and applying AMPs.