Genome sequencing of Enterococcus faecium NT04, an oral microbiota revealed the production of enterocin A/B active against oral pathogens.

Objective: This study aimed to isolate and investigate a bacterium from an Egyptian adult's healthy oral cavity, focusing on its probiotic properties, especially its antagonistic activity against oral pathogens. Methods: The isolated bacterium NT04 using 16S rRNA gene sequencing, was identified as Enterococcus faecium. In this study, the whole genome of Enterococcus faecium NT04 was sequenced and annotated by bioinformatics analysis tools. Results: Numerous genes encoding the production of diverse metabolic and probiotic properties, such as bacteriocin-like inhibitory substances (Enterocin A and B), cofactors, antioxidants, and vitamins, were confirmed by genomic analysis. There were no pathogenicity islands or plasmid insertions found. This strain is virulent for host colonization rather than invasion. Conclusion: Genomic characteristics of strain NT04 support its potentiality as an anti-oral pathogen probiotic candidate.

Irinotecan-gut microbiota interactions and the capability of probiotics to mitigate Irinotecan-associated toxicity.

BACKGROUND: Irinotecan is a chemotherapeutic agent used to treat a variety of tumors, including colorectal cancer (CRC). In the intestine, it is transformed into SN-38 by gut microbial enzymes, which is responsible for its toxicity during excretion. OBJECTIVE: Our study highlights the impact of Irinotecan on gut microbiota composition and the role of probiotics in limiting Irinotecan-associated diarrhea and suppressing gut bacterial ß-glucuronidase enzymes. MATERIAL AND METHODS: To investigate the effect of Irinotecan on the gut microbiota composition, we applied 16S rRNA gene sequencing in three groups of stool samples from healthy individuals, colon cancer, and Irinotecan treated patients (n = 5/group). Furthermore, three Lactobacillus spp.; Lactiplantibacillus plantarum (L. plantarum), Lactobacillus acidophilus (L. acidophilus), Lacticaseibacillus rhamnosus (L. rhamnosus) were used in a single and mixed form to in-vitro explore the effect of probiotics on the expression of ß-glucuronidase gene from E. coli. Also, probiotics were introduced in single and mixed forms in groups of mice before the administration of Irinotecan, and their protective effects were explored by assessing the level of reactive oxidative species (ROS) as well as studying the concomitant intestinal inflammation and apoptosis. RESULTS: The gut microbiota was disturbed in individuals with colon cancer and after Irinotecan treatment. In the healthy group, Firmicutes were more abundant than Bacteriodetes, which was the opposite in the case of colon-cancer or Irinotecan treated groups. Actinobacteria and Verrucomicrobia were markedly present within the healthy group, while Cyanobacteria were noted in colon-cancer and the Irinotecan-treated groups. Enterobacteriaceae and genus Dialister were more abundant in the colon-cancer group than in other groups. The abundance of Veillonella, Clostridium, Butryicicoccus, and Prevotella were increased in Irinotecan-treated groups compared to other groups. Using Lactobacillus spp. mixture in mice models significantly relieved Irinotecan-induced diarrhea through the reduction of both ß-glucuronidase expression and ROS, in addition to guarding gut epithelium against microbial dysbiosis and proliferative crypt injury. CONCLUSIONS: Irinotecan-based chemotherapy altered intestinal microbiota. The gut microbiota participates greatly in determining both the efficacy and toxicity of chemotherapies, of which the toxicity of Irinotecan is caused by the bacterial ß-glucuronidase enzymes. The gut microbiota can now be aimed and modulated to promote efficacy and decrease the toxicity of chemotherapeutics. The used probiotic regimen in this study lowered mucositis, oxidative stress, cellular inflammation, and apoptotic cascade induction of Irinotecan.

A combined inactivated cholera and hepatitis A vaccine-induced potent protective immunity in a mouse model.

Cholera and hepatitis A are serious infections spread by consuming contaminated food or water. Vaccination is the most effective strategy to prevent them. Inactivated vaccines are available for both diseases. Our goal in this study is to evaluate the immunogenic response of hepatitis A and cholera combination vaccines compared to the separate vaccines. Hepatitis A and cholera vaccine formulations with and without adjuvants (alum or chitosan) were developed and injected into mice intraperitoneally. We measured the rate of seroconversion; serum-specific antibody titers; lymphoproliferation analysis; cytokine secretions for IL2, IL4, IL10, and IFN-; and a challenge test against cholera strains in the vaccinated mice. Based on the results, the combined vaccination formulation, whether adjuvanted or not, significantly boosted the immune response on both humoral and cellular levels against both hepatitis A and cholera antigens compared to the individual vaccines. These findings validated an important concept for developing an effective combined cholera and hepatitis A vaccine that could be introduced as a novel combined vaccine for travelers as part of a standard immunization schedule. KEY POINTS: • Cholera and hepatitis A combined vaccines (with or without adjuvants) were prepared. • The vaccines were injected into mice groups for humoral and cellular immunity evaluation. • Combined vaccines gave substantial protection against both immunogens.

Genomic analysis of Enterococcus durans NT21, a putative bacteriocin-producing isolate.

Enterococcus species are a long-standing and non-pathogenic commensal bacterium, representing an important part of the normal. Enterococcus durans is a rarely isolated species from animals and humans, and it was a tiny constituent of human oral cavity and animal intestinal flora, as well as animal-derived foods, particularly dairy products. This study evaluated the security of our strain E. durans NT21 by using whole-genome sequencing (WGS), physicochemical features, and antimicrobial activity. The complete genomic of our strain Enterococcus durans NT21was sequenced and analyzed by using several bioinformatics tools to identify bacteriocin genes, virulence genes, antibiotic resistance genes, Crispr-Cas and pathogenicity islands. The results showed that our strain NT21 lacks the presence of virulence genes, pathogenicity islands, plasmids and has only two antibiotic resistance genes. On the other hand, it produces three bacteriocin-like inhibitory substances (Enterolysin A, P and L50a). It has six gene-encoded Crisper-Cas and one cluster Crispr-Cas gene. According to our findings, E. durans NT21 is a possible probiotic strain that is safe for both human and animal use.

Wound Healing Metabolites from Peters' Elephant-Nose Fish Oil: An In Vivo Investigation Supported by In Vitro and In Silico Studies.

Gnathonemuspetersii (F. Mormyridae) commonly known as Peters' elephant-nose fish is a freshwater elephant fish native to West and Central African rivers. The present research aimed at metabolic profiling of its derived crude oil via GC-MS analysis. In addition, wound healing aptitude in adult male New Zealand Dutch strain albino rabbits along with isolated bioactive compounds in comparison with a commercial product (Mebo®). The molecular mechanism was studied through a number of in vitro investigations, i.e., radical scavenging and inhibition of COX enzymes, in addition to in silico molecular docking study. The results revealed a total of 35 identified (71.11%) compounds in the fish oil, belonging to fatty acids (59.57%), sterols (6.11%), and alkanes (5.43%). Phytochemical investigation of the crude oil afforded isolation of six compounds 1-6. Moreover, the crude oil showed significant in vitro hydrogen peroxide and superoxide radical scavenging activities. Furthermore, the crude oil along with one of its major components (compound 4) exhibited selective inhibitory activity towards COX-2 with IC50 values of 15.27 and 2.41 µM, respectively. Topical application of the crude oil on excision wounds showed a significant (p < 0.05) increase in the wound healing rate in comparison to the untreated and Mebo®-treated groups, where fish oil increased the TGF-ß1 expression, down-regulated TNF-α, and IL-1ß. Accordingly, Peters' elephant-nose fish oil may be a potential alternative medication helping wound healing owing to its antioxidant and anti-inflammatory activities.

Chitosan and alginate salt as biomaterials are potential natural adjuvants for killed cholera vaccine.

Chitosan and alginate salts are natural biopolymers that have gained recent attention in the biomedical sectors. Their properties allow them to become potential candidates as safe, cheap, and effective vaccine adjuvants. The present study aimed to enhance the immunogenic response of a current injectable killed cholera vaccine (KCV) using chitosan and alginate salt as natural adjuvants against alum. We tested KCV adjuvanted with alum, chitosan, and sodium alginate in mice. Mice were immunized intraperitoneally with KCV adjuvanted with alum, chitosan, or alginate salt and compared with a control unadjuvanted immunized group. Humoral, cellular, and functional immune responses were evaluated in all groups. The addition of adjuvants, particularly natural adjuvants, to KCV significantly improved the immune response as demonstrated by specific antibody increase, strong proliferation effects, and high protection rate against different challenge doses of cholera strains. Our findings demonstrate that chitosan and alginate salt are superior adjuvants for boosting the KCV immune response and highlights the requirement for further vaccine development.

Development and machine-learning optimization of mucoadhesive nanostructured lipid carriers loaded with fluconazole for treatment of oral candidiasis.

The aim of this work was to prepare and optimize mucoadhesive nanostructured lipid carrier (NLC) impregnated with fluconazole for better management of oral candidiasis. The NLCs were fabricated using an emulsification/sonication technique. The nanoparticles consisted of stearic acid, oleic acid, Pluronic F127, and lecithin. Box-Behnken design, artificial neural networking, and variable weight desirability were employed to optimize the joint effect of drug concentration in the drug/lipid mixture, solid lipid concentration in the solid/liquid lipid mixture, and surfactant concentration in the total mixture on size and entrapment. The optimized NLCs were coated with chitosan. The nanoparticles were characterized by surface charge, spectroscopic, thermal, morphological, mucoadhesion, release, histopathological, and antifungal properties. The nanoparticles are characterized by a particle size of 335 ± 13.5 nm, entrapment efficiency of 73.1 ± 4.9%, sustained release, minor histopathological effects on rabbit oral mucosa, and higher fungal inhibition efficiency for an extended period of time compared with fluconazole solution. Coating the nanoparticles with chitosan increased its adhesion to rabbit oral buccal mucosa and improved its anti-candidiasis activity. It is concluded that mucoadhesive lipid-based nanoparticles amplify the effect of fluconazole on Candida albicans in vitro. This finding warrants pre-clinical and clinical studies in oral candidiasis disease models to corroborate in vitro findings.

Anti-Proliferative and Anti-Biofilm Potentials of Bacteriocins Produced by Non-Pathogenic Enterococcus sp.

The incidence of cancer is increasing worldwide; likewise, the emergence of antibiotic-resistant biofilm-forming pathogens has led to a tremendous increase in morbidity and mortality. This study aimed to evaluate the probiotic properties of bacteriocin-producing Enterococcus sp. with a focus on their anti-biofilm and anticancer activities. Three of 79 Enterococcus isolates (FM43, FM65, FM50) were identified as producers of broad-spectrum bioactive molecules and were molecularly characterized as Enterococcus faecium by 16S rRNA sequencing. Phenotypic and genotypic screening for potential virulence factors revealed no factors known to promote pathogenicity. Treatment with proteinase K resulted in diminished antimicrobial activity; PCR-based screening for bacteriocin genes suggested the presence of both entA and entB genes that encode enterocins A and B, respectively. Maximum antimicrobial activity was detected during the early stationary phase, while activity disappeared after 24 h in culture. Bacteriocins from these isolates were stable at high temperatures and over a wide range of pH. Interestingly, crude supernatants of Ent. faecium FM43 and Ent. faecium FM50 resulted in significant destruction (80% and 48%, respectively; P < 0.05) of Streptococcus mutans ATCC 25175-associated preformed biofilms. Moreover, in vitro cytotoxicity assays revealed that extracts from Ent. faecium isolates FM43, FM65, and FM50 inhibited Caco-2 cell proliferation by 76.9%, 70%, and 85.3%, respectively. Taken together, the multifunctional capabilities of the microbial-derived proteins identified in our study suggest potentially important roles as alternative treatments for biofilm-associated infections and cancer.

Alginate-coated chitosan nanoparticles act as effective adjuvant for hepatitis A vaccine in mice.

The numerous recent hepatitis A outbreaks emphasize the need for vaccination; despite the effectiveness of the current ones, developments are needed to overcome its high cost plus some immune response limitations. Our study aims to evaluate the use of chitosan and alginate-coated chitosan nanoparticles as an adjuvant/carrier for the hepatitis A vaccine (HAV) against the traditional adjuvant alum. Immune responses towards (HAV-Al) with alum, (HAV-Ch) with chitosan, and (HAV-aCNP) with alginate-coated chitosan nanoparticles, were assessed in mice. HAV-aCNP significantly improved the immunogenicity by increasing the seroconversion rate (100%), the hepatitis A antibodies level, and the splenocytes proliferation. Thus, the HAV-aCNP adjuvant was superior to other classes in IFN-γ and IL-10 development. Meanwhile, the solution formula of HAV with chitosan showed comparable humoral and cellular immune responses to alum-adjuvanted suspension with a balanced Th1/Th2 immune pathway. The current study showed the potential of alginate-coated chitosan nanoparticles as an effective carrier for HAV. Consequently, this would impact the cost of HAV production positively.