Yeast oral vaccines against infectious diseases.

Vaccines that are delivered orally have several advantages over their counterparts that are administered via injection. Despite the advantages of oral delivery, however, approved oral vaccines are currently limited either to diseases that affect the gastrointestinal tract or to pathogens that have a crucial life cycle stage in the gut. Moreover, all of the approved oral vaccines for these diseases involve live-attenuated or inactivated pathogens. This mini-review summarizes the potential and challenges of yeast oral vaccine delivery systems for animal and human infectious diseases. These delivery systems utilize whole yeast recombinant cells that are consumed orally to transport candidate antigens to the immune system of the gut. This review begins with a discussion of the challenges associated with oral administration of vaccines and the distinct benefits offered by whole yeast delivery systems over other delivery systems. It then surveys the emerging yeast oral vaccines that have been developed over the past decade to combat animal and human diseases. In recent years, several candidate vaccines have emerged that can elicit the necessary immune response to provide significant protection against challenge by pathogen. They serve as proof of principle to show that yeast oral vaccines hold much promise.

Developing a COVID-19 Yeast Oral Vaccine for Low Income Countries

The novel COVID-19 vaccines have been instrumental at transforming the pandemic into an endemic disease. However, many contemporary vaccines, especially the landmark mRNA vaccines, require cold storage that makes them difficult for low income and developing countries to keep and distribute, and no shelf stable, low-cost alternative currently exists. In response to this need, we are developing a novel COVID-19 vaccine delivery system using the probiotic yeast Saccharomyces boulardii. We engineered an integrating construct to express the receptor binding domain (RBD) of the SARS-CoV-2 spike protein tagged with the yeast pheromone secretion signal and with the Claudin-4 targeting sequence of the Clostridium perfringens enterotoxin. Preliminary data from two animal trials suggest that our candidate yeast oral COVID-19 vaccine can trigger a robust humoral immune response in mice. Experiments are underway to assess its effect on the murine T-cell response. Our laboratory is supported in part by a research grant from the PCHRD-DOST of the Republic of the Philippines.Copyright © 2023 The American Society for Biochemistry and Molecular Biology, Inc.

Current status of probiotic and related health benefits

This review is aimed to explore the health beneficial effects of probiotics which are live microorganisms that provide a positive health influence on humans when taken in sufficient quantity. Lactic acid bacteria, bifidobacteria, and yeast are frequently used as probiotics. These health-beneficial bacteria could compete with pathogens and modulate the gut microbiota, and exhibit immunomodulatory, anti-obesity, anti-diabetic, and anti-cancer activities which are discussed in this review. Moreover, recent studies showed that probiotics could neutralize COVID-19 infections. Hence, probiotics have become an alternative to several drugs including antibiotics. In addition, probiotic efficacy also depends on the delivery system as the delivery agents help the bacteria to survive in the harsh environment of the human gut. Considering these health benefits of probiotics, now it has been applied to different food materials which are designated as functional food. This review explored a portrait of the beneficial effects of probiotics on human health.Copyright © 2022 The Author(s)

[Efficacy of Saccharomyces boulardii CNCM I-745 probiotic drug in the prevention and treatment of diarrhea in hospitalized patients with new coronavirus infection COVID-19].

AIM: To evaluate the efficacy of Saccharomyces boulardii (S. boulardii) CNCM I-745 probiotic drug in preventing and treating diarrhea in hospitalized patients with COVID-19. MATERIALS AND METHODS: A prospective comparative study was conducted in two parallel groups. The study included males and females aged 18 to 60 with the following diagnosis confirmed by polymerase chain reaction: U07.2 Coronavirus infection COVID-19, caused by SARS-CoV-2 virus (grade 1-3 pneumonia according to CT scan). All patients received antibiotic therapy. The patients were subdivided into two equal groups (n=60) depending on the administration of S. boulardii CNCM I-745 probiotic drug in addition to standard treatment. The probiotic was prescribed by the attending physician; the dose was 2 capsules per day (500 mg/day) 30 min before the meal for 10 days. All patients were monitored for main clinical, laboratory, and instrumental parameters during the study. In addition, the symptom of diarrhea (stool with a frequency of more than 3 times a day of type 6 and 7 according to the Bristol stool scale), including its frequency, duration, and the number of bowel movements of loose stool per day were precisely evaluated in both groups. RESULTS: In the overall patient pool, diarrhea was reported in 21.7% of in-patients during the observation period (95% confidence interval [CI] 14.2-29.1) with a mean duration of 4.6154 days (95% CI 3.7910-5.4398). The incidence of diarrhea in group 1 was 13.3% (95% CI 4.5-22.2), and in group 2, it was 30.0% (95% CI 18.1-41.9). Relative risk showed that the use of the S. boulardii CNCM I-745 probiotic drug leads to a significant reduction in the risk of diarrhea in hospitalized patients with COVID-19 infection receiving antibiotic therapy (odds ratio [OR] 0.3590, 95% CI 0.1421-0.9069; p=0.0303). In group 1, the duration of diarrhea was 3.1250 days (95% CI 2.5892-3.6608) versus 5.2778 days (95% CI 4.2290-6.3265) in group 2, p=0.0112. The mean daily frequency of loose stools in patients with diarrhea in group 1 was 3.2500 (95% CI 2.6588-3.8412) versus 4.3889 (95% CI 3.7252-5.0525) in group 2, p=0.0272. The secondary endpoint, duration of hospital stay, was also significantly shorter in group 1 patients - 11.6833 days (95% CI 11.2042-12.1625) versus 12.7333 days (95% CI 12.1357-13.3309) in group 2, p=0.0120. CONCLUSION: The present prospective comparative study demonstrated that adding S. boulardii CNCM I-745 probiotic drug into the standard treatment regimen of patients with new coronavirus infection COVID-19 receiving antibiotic therapy helps reduce the incidence of diarrhea and its severity during hospitalization, as well as the duration of hospital stay.

Determination of Probiotics Prescription Indications in Patients with Irritable Bowel Syndrome (Materials of the Expert Council and Literature Review)

Aim. To review the main indications for probiotics prescription in patients with irritable bowel syndrome and to present the materials of an Expert Council, which was held on 18 March 2022 in Moscow. Key points. Gut microbiota disturbance is an integral part of irritable bowel syndrome (IBS) pathogenesis. Changes of colonic microbiota composition are associated with its functional potential modification, which leads to an increasing of the pro-inflammatory immune response, as well as to an exacerbation of the disease symptoms and quality of life decreasing in patients with IBS. The novel coronavirus infection (COVID-19) is an independent risk factor for both exacerbation and onset of IBS, which predispose to increase IBS incidence. Correction of gut microbiota composition with probiotics seems to be a promising therapeutic target for IBS treatment optimizing. The optimal probiotic should be effective, safe, strain-specific, and its dose and duration of administration should be confirmed by the results of clinical studies. Some of the probiotics with proven efficacy in IBS are Alflorex® and Enterol®. Conclusion. Prescription of certain probiotics in IBS is advisable to normalize the frequency and consistency of stools, relieve abdominal pain and bloating, as well as improve patients’ quality of life. © 2022 Editorial Department of Scientia Agricultura Sinica. All rights reserved.