Antiviral potential of lactic acid bacteria and their bacteriocins

Potential Adjuvant Therapeutic Effect of Lactobacillus plantarum Probio-88 Postbiotics against SARS-COV-2

In response to the ongoing COVID-19 pandemic, the global effort to develop high efficacy countermeasures to control the infection are being conducted at full swing. While the efficacy of vaccines and coronavirus drugs are being tested, the microbiome approach represents an alternative pathophysiology-based approach to prevent the severity of the infection. In the current study, we evaluated the action of a novel probiotic Lactobacillus plantarum Probio-88 against SARS-COV-2 replication and immune regulation using an in vitro and in silico study. The results showed that extract from this strain (P88-CFS) significantly inhibited the replication of SARS-COV-2 and the production of reactive oxygen species (ROS) levels. Furthermore, compared with infected cells, P88-CFS treated cells showed a significant reduction in inflammatory markers such as IFN-α, IFN-β, and IL-6. Using an in silico molecular docking approach, it was postulated that the antiviral activity of L. plantarum Probio-88 was derived from plantaricin E (PlnE) and F (PlnF). The high binding affinity and formation of hydrogen bonding indicated that the association of PlnE and PlnF on SARS-COV-2 helicase might serve as a blocker by preventing the binding of ss-RNA during the replication of the virus. In conclusion, our study substantiated that P88-CFS could be used as an integrative therapeutic approach along with vaccine to contain the spread of the highly infectious pathogen and possibly its variants.

Quantitative Real-Time PCR and Digital PCR to Evaluate Residual Quantity of HAV in Experimentally Depurated Mussels

Kinetics of hepatitis A virus (HAV) accumulation and depuration from mussels (Mytilus galloprovincialis) was studied in an experimental depuration system. Different parameters likely to influence the rate of virus accumulation and elimination were evaluated. Analyses were carried out by both real-time RT-qPCR and digital PCR. Results demonstrated that the animals start to concentrate the virus already after one hour and reach the maximum level of contamination in 6 h of experiment. With respect to depuration, HAV showed a rapid reduction of the concentration (89%) during the first 24-48 h of experiment and a very slow virus decrement in the following days with a 1% residual RNA at the ninth day of depuration. When process parameters likely to increase the depuration rate (presence of ozone, microalgal feeding, presence of lactic bacteria, pre-treatment with digestive enzymes) were tested, no significant differences in the kinetics were observed. Only treatment with pancreatin seemed to positively affect depuration in the first two days of the experiment.

Dietary inclusion of watermelon rind powder and Lactobacillus plantarum: Effects on Nile tilapia's growth, skin mucus and serum immunities, and disease resistance

An eight-week investigation was conducted to access the potential impact of dietary watermelon rind powder (WMRP) and L. plantarum CR1T5 (LP) administered individually or in combination on immunity, disease resistance, and growth rate of Nile tilapia fingerlings cultured in a biofloc system. Three hundred twenty fish (average weight 16.57 ± 0.14 g) were distributed into 16 tanks at a rate of 20 fish per tank. The fish were fed different diets: Diet 1 (0 g kg^-1 WMRP and 0 CFU g^-1 L. plantarum) (control), Diet 2 (40 g kg^-1 WMRP), Diet 3 (10⁸ CFU g^-1 LP), and Diet 4 (40 g kg^-1 WMRP + 10⁸ CFU g^-1 LP) for eight weeks. A completely randomized design (CRD) with four replications was applied. Skin mucus, serum immunity, and growth parameters were analyzed every 4 weeks, and a challenge study against S. agalactiae was conducted at the end of the experiment. The findings showed that the inclusion of WMRP + LP, administrated individually or in a mixture, significantly (P<0.05) stimulated growth, skin mucus, and serum immune parameters of Nile tilapia fingerlings compared with the control. The highest values were detected in fish fed the combination of WMRP and LP, as opposed to individual administration of either WMRP or LP, in which no significant differences were detected. Within the challenge study, the relative percent survival (RPS) in Diet 2, Diet 3, and Diet 4 was 48.0%, 52.0%, and 68.0%, respectively. Fish fed 40 g kg^-1 WMRP + LP produced significantly higher RPS and protection against S. agalactiae than the other treated groups. Current results suggest that the dual administration of WMRP and LP maybe an effective feed additive for Nile tilapia grown in an indoor biofloc system, capable of improving growth parameters and increasing resistance to S. agalactiae infection.

A Microbiome-Driven Approach to Combating Depression During the COVID-19 Pandemic

The significant stressors brought about and exacerbated by COVID-19 are associated with startling surges in mental health illnesses, specifically those related to depressive disorders. Given the huge impact of depression on society, and an incomplete understanding of impactful therapeutics, we have examined the current literature surrounding the microbiome and gut-brain axis to advance a potential complementary approach to address depression and depressive disorders that have increased during the COVID-19 pandemic. While we understand that the impact of the human gut microbiome on emotional health is a newly emerging field and more research needs to be conducted, the current evidence is extremely promising and suggests at least part of the answer to understanding depression in more depth may lie within the microbiome. As a result of these findings, we propose that a microbiome-based holistic approach, which involves carefully annotating the microbiome and potential modification through diet, probiotics, and lifestyle changes, may address depression. This paper's primary purpose is to shed light on the link between the gut microbiome and depression, including the gut-brain axis and propose a holistic approach to microbiome modification, with the ultimate goal of assisting individuals to manage their battle with depression through diet, probiotics, and lifestyle changes, in addition to offering a semblance of hope during these challenging times.

Could Probiotics and Postbiotics Function as "Silver Bullet" in the Post-COVID-19 Era?

We are currently experiencing the realities of the most severe pandemic within living memory, with major impacts on the health and economic well-being of our planet. The scientific community has demonstrated an unprecedented mobilization capability, with the rapid development of vaccines and drugs targeting the protection of human life and palliative measures for infected individuals. However, are we adequately prepared for ongoing defense against COVID-19 and its variants in the post-pandemic world? Moreover, are we equipped to provide a satisfactory quality of life for individuals who are recovering from COVID-19 disease? What are the possibilities for the acceleration of the recovery process? Here, we give special consideration to the potential and already-demonstrated role of probiotics and traditional medical approaches to the management of current and potential future encounters with our major virus adversaries.

Screening of Lactic Acid Bacterial Strains with Antiviral Activity Against Porcine Epidemic Diarrhea

Newly emerging and re-emerging viral infectious diseases cause significant economic losses in swine production. Efficacious vaccines have not yet been developed for several major swine infectious diseases, including porcine epidemic diarrhea virus (PEDV). We used the PEDV-infected Vero cell model to screen lactic acid bacteria (LAB) strains with antiviral activity. Sixty LAB strains were isolated from the feces of nursing piglets. After the elimination of LAB strains with high cytotoxicity to Vero cells, the protective effects of the remaining 6 strains against PEDV infection were determined. Vero cells pretreated with the intracellular extracts or cell wall fractions of YM22 and YM33 strains for 24 h before infection with PEDV showed significantly higher cell viabilities and lower mRNA expression of PEDV nucleocapsid (PEDV-N) than the unpretreated cells, indicating that the intracellular extracts and cell wall fractions of YM22 and YM33 possessed prophylactic effects on Vero cells against PEDV infection. PEDV-infection significantly increased the mRNA expression of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8) in Vero cells. However, pretreatment of Vero cells with the cell wall fractions of YM22 and YM33 decreased the mRNA expression of TNF-α and IL-8, which could be a mechanism associated with the protective effects of YM22 and YM33 against PEDV. Based on the biochemical characteristics and phylogenetic analyses, YM22 and YM33 were identified as Ligilactobacillus agilis (basonym: Lactobacillus agilis) and Ligilactobacillus salivarius (basonym: Lactobacillus salivarius), respectively. These findings suggest that L. agilis YM22 and L. salivarius YM33 could provide some levels of protective effects against PEDV infections.

Gut Dysbiosis during COVID-19 and Potential Effect of Probiotics

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an RNA virus of the family Coronaviridae, causes coronavirus disease 2019 (COVID-19), an influenza-like disease that chiefly infects the lungs through respiratory transmission. The spike protein of SARS-CoV-2, a transmembrane protein in its outer portion, targets angiotensin-converting enzyme 2 (ACE2) as the binding receptor for the cell entry. As ACE2 is highly expressed in the gut and pulmonary tissues, SARS-CoV-2 infections frequently result in gastrointestinal inflammation, with presentations ordinarily ranging from intestinal cramps to complications with intestinal perforations. However, the evidence detailing successful therapy for gastrointestinal involvement in COVID-19 patients is currently limited. A significant change in fecal microbiomes, namely dysbiosis, was characterized by the enrichment of opportunistic pathogens and the depletion of beneficial commensals and their crucial association to COVID-19 severity has been evidenced. Oral probiotics had been evidenced to improve gut health in achieving homeostasis by exhibiting their antiviral effects via the gut-lung axis. Although numerous commercial probiotics have been effective against coronavirus, their efficacies in treating COVID-19 patients remain debated. In ClinicalTrials.gov, 19 clinical trials regarding the dietary supplement of probiotics, in terms of Lactobacillus and mixtures of Bifidobacteria and Lactobacillus, for treating COVID-19 cases are ongoing. Accordingly, the preventive or therapeutic role of probiotics for COVID-19 patients can be elucidated in the near future.

Double-Barrel Shotgun: Probiotic Lactic Acid Bacteria with Antiviral Properties Modified to Serve as Vaccines

Contrary to the general belief that the sole function of probiotics is to keep intestinal microbiota in a balanced state and stimulate the host’s immune response, several studies have shown that certain strains of lactic acid bacteria (LAB) have direct and/or indirect antiviral properties. LAB can stimulate the innate antiviral immune defence system in their host, produce antiviral peptides, and release metabolites that prevent either viral replication or adhesion to cell surfaces. The SARS-CoV (COVID-19) pandemic shifted the world’s interest towards the development of vaccines against viral infections. It is hypothesised that the adherence of SARS-CoV spike proteins to the surface of Bifidobacterium breve could elicit an immune response in its host and trigger the production of antibodies. The question now remains as to whether probiotic LAB could be genetically modified to synthesize viral antigens and serve as vaccines—this concept and the role that LAB play in viral infection are explored in this review.

The promising biological role of postbiotics derived from probiotic Lactobacillus species in reproductive health

Recent investigations have meaningfully developed our knowledge of the features of the reproductive microbiome/metabolome profile and their relations with host responses to offer an optimal milieu for the development of the embryo during the peri-implantation period and throughout pregnancy. In this context, the establishment of homeostatic circumstances in the Female Reproductive Tract (FRT), in various physiological periods, is a significant challenge, which appears the application of postbiotics can facilitate the achievement of this goal. So, currently, scientific literature confirms that postbiotics due to their antimicrobial, antiviral, and immunomodulatory properties can be considered as a novel biotherapeutic approach. Future investigation in this field will shed more translational mechanistic understanding of the interaction of the postbiotics derived from vaginal Lactobacilli with females' health and reproduction.

Genome Features and In Vitro Activity against Influenza A and SARS-CoV-2 Viruses of Six Probiotic Strains

Purpose

The aim of this work was to analyze the complete genome of probiotic bacteria Lactobacillus plantarum 8 RA 3, Lactobacillus fermentum 90 TC-4, Lactobacillus fermentum 39, Bifidobacterium bifidum 791, Bifidobacterium bifidum 1, and Bifidobacterium longum 379 and to test their activity against influenza A and SARS-CoV-2 viruses.

Methods

To confirm the taxonomic affiliation of the bacterial strains, MALDI TOF mass spectrometry and biochemical test systems were used. Whole genome sequencing was performed on the Illumina Inc. MiSeq platform. To determine the antiviral activity, A/Lipetsk/1V/2018 (H1N1 pdm09) (EPI_ISL_332798) and A/common gull/Saratov/1676/2018 (H5N6) (EPI_ISL_336925) influenza viruses and SARS-CoV-2 virus strain Australia/VIC01/2020 (GenBank: MT007544.1) were used.

Results

All studied probiotic bacteria are nonpathogenic for humans and do not contain the determinants of transmission-type antibiotic resistance and integrated plasmids. Resistance to antibiotics of different classes is explained by the presence of molecular efflux pumps of the MatE and MFS families. Cultures of L. fermentum 90 TC 4, L. plantarum 8 RA 3, and B. bifidum 791 showed a pronounced activity against influenza A viruses in MDCK cells. Activity against the SARS-CoV-2 virus was demonstrated only by the L. fermentum 90 TC 4 strain in VERO cells.

Conclusions

The studied probiotic bacteria are safe, have antiviral activity, and are of great importance for the prevention of diseases caused by respiratory viruses that can also infect the human intestine.

Immunomodulatory role and potential utility of various nutrients and dietary components in SARS-CoV-2 infection

Recently, the outbreak of severe acute respiratory syndrome cornoavirus-2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), has become a great perturbation all around the globe and has many devastating effects on every aspect of life. Apart from the oxygen therapy and extracorporeal membrane oxygenation, Remdesivir and Dexamethasone have been proven to be efficacious against COVID-19, along with various vaccine candidates and monoclonal antibody cocktail therapy for Regeneron. All of these are currently at different stages of clinical trials. People with weak immunity are more prone to a severe infection of SARS-CoV-2. Therefore, early and judicious nutritional supplementation along with pharmacological treatment and clinician collaborations are critical in restituting the current situation. Nutritional supplements help in acquiring strong immunity to prevent the progression of disease any further. Vitamin C, vitamin D, selenium, zinc and many other nutritional and dietary supplements inhibit the production of inflammatory cytokines during a viral infection and prevents several unwanted symptoms of infection. Many dietary components like citrus fruits, black elderberry, ginger, and probiotics have the ability to attack viral replication. These supplements can also tame the overriding immune system during coronavirus infection. Keeping in view these facts, nutritional and dietary supplements can be used along with other management modalities. These nutritional and dietary supplements are potential candidates to curb the convulsive unfolding of novel COVID-19, in combination with other standard treatment protocols. In this review, various search engines were used to exploit available literature in order to provide a comprehensive review on nutritional and dietary supplements with respect to the viral infections. It will also provide a brief overview on some of the clinical trials that are in progress to assess the role of nutritional supplements, either alone or in combination with other pharmacological drugs, in fight against COVID-19.

Respiratory syndrome coronavirus-2 response: Microbiota as lactobacilli could make the difference

Coronavirus disease 2019 (COVID-19) is caused by respiratory syndrome coronavirus qualified as SARS-CoV-2. Viral penetration requires binding of the viral spike (S) protein to a specific cellular receptor (ACE2) highly expressed in a nasal goblet and ciliated cells. In several countries, the COVID-19 evolution was relatively benign compared to others and despite noncompliance with health recommendations on several occasions. In this overview, we attempt to define the criteria that could explain such a difference. Among these criteria, the specificity of Lactobacillus genus strains, as a part of nasal microbiota, could play a role of a barrier against viral penetration and could strengthen the host's immune system in some populations rather than others. In fact, several studies have shown the role of lactic acid bacteria, including lactobacilli, in the prevention of viral respiratory infections. This could provide important information on a possible mechanism of the virus spreading.

Prophylactic effects of probiotics on respiratory viruses including COVID-19: a review

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is mainly transmitted through respiratory droplets. The symptoms include dry cough, fever, and fatigue; however, high propagation, mutation, and fatality rates have been reported for SARS-CoV-2. This review investigates the structure of SARS-CoV-2, antiviral mechanisms, preventive strategies, and remedies against it. Effective vaccines have been developed by Pfizer (95% effective), AstraZeneca (90% effective), Moderna (94.5% effective) vaccine, among others. However, herd immunity is also required. Probiotics play a major role in the gut health, and some are known to have therapeutic potential against viral infections. Their modes of antiviral activities include direct interaction with targeted viruses, production of antiviral metabolites, and immunomodulatory effects on the host. Hence, probiotics can be a useful prophylactic against COVID-19, and more studies are required on the effects of probiotics against other viral infections that may occur in future.

Exopolysaccharides as Antimicrobial Agents: Mechanism and Spectrum of Activity

Exopolysaccharides (EPSs) are metabolites synthesized and excreted by a variety of microorganisms, including lactic acid bacteria (LAB). EPS serve several biological functions such as interactions between bacteria and their environments, protection against hostile conditions including dehydration, the alleviation of the action of toxic compounds (bile salts, hydrolyzing enzymes, lysozyme, gastric, and pancreatic enzymes, metal ions, antibiotics), and stresses (changing pH, osmolarity), and evasion of the immune response and phage attack. Bacterial EPSs are considered valuable by the food, pharmaceutical, and nutraceutical industries, owing to their health-promoting benefits and rheological impacts. Numerous studies have reported the unusual antimicrobial activities of various EPS against a wide variety of pathogenic microbes (bacteria, virus, and fungi). This review aims to provide a comprehensive examination of the in vitro and in vivo antimicrobial activities of different EPSs, mainly against foodborne bacterial, fungal, and viral pathogens. The mechanism of EPS action against these pathogens as well as the methods used to measure antimicrobial activities are critically reviewed.

Microbiome Dysbiosis and Predominant Bacterial Species as Human Cancer Biomarkers

PURPOSE

To evaluate bacterial agents as cancer biomarkers.

METHODS AND RESULTS

Various bacterial species have been demonstrated to involve in human cancers. However, the data is not enough for better understanding of predominant specific species. Application of a rapid and early-diagnostic, cost-effective, non-invasive, and inclusive method is a crucial approach for obtaining valid results. The role of Helicobacter pylori (H. pylori) in gastric and duodenal cancer has been confirmed. From investigation among previous publications, we attempted to make it clear which bacterial species significantly and specifically increase in various cancer types. It was unraveled that there is significant change in Granulicatella adiacens (G. adiacens) in lung cancer (LC), Fusobacterium nucleatum (F. nucleatum) in colorectal cancer (CRC), H. pylori and Porphyromonas gingivalis (P. gingivalis) in pancreatic cancer, and Streptococcus spp. in oral cancer.

CONCLUSION

Alteration in the cell cycle by means of different mechanisms such as inflammation, alteration in cell signaling, invasion and immune evasion, specific niche colonization, induction of DNA damage and mutation, expression of some microRNAs, and enhancing epigenetic effects are the most common mechanisms employed by bacterial species.

Effects of Feed Mixed with Lactic Acid Bacteria and Carbon, Nitrogen, Phosphorus Supplied to the Water on the Growth and Survival Rate of White Leg Shrimp (Penaeus vannamei) Infected with Acute Hepatopancreatic Necrosis Disease Caused by Vibrio parahaemolyticus

Simple Summary

This study aimed to evaluate the growth, survival rate, and resistance to Acute hepatopancreatic Necrosis Disease (AHPND) of white leg shrimp (Penaeus vannamei) by using Lactobacillus plantarum, Lactobacillus fermentum, and Pediococcus pentosaceus mixed with feed, and at the same time supplying CNP in a ratio of 15:1:0.1 to the water. The result showed that shrimps were fed with feed containing lactic acid bacteria (LAB), especially L. plantarum have an effective to increased shrimp growth, stimulated non-specific immune system such as total hemocyte cells, granulocyte cells, hyaline cells, and protected shrimp to ANPND. The supply of CNP to the water have increased the intensity of V. parahaemolyticus effects on shrimp health; significantly decreased non-specific immune parameters of shrimp by 30–50%, therefore increased the AHPND infected rate and mortality of shrimp compared with without CNP group. In summary, LAB has a good effect to shrimp and the supply of CNP had significantly reduced the shrimp’s immune response and increased the susceptibility of shrimp to AHPND in both cases of use with and without LAB-containing diets.

Abstract

This study aimed to evaluate the growth, survival rate, and resistance to acute hepatopancreatic necrosis disease (AHPND) of white leg shrimp (Penaeus vannamei) by using Lactobacillus plantarum, Lactobacillus fermentum, and Pediococcus pentosaceus mixed with feed, and at the same time supplying CNP in a ratio of 15:1:0.1 to the water. As a result, the treatments that shrimp were fed with feed containing lactic acid bacteria (LAB), especially L. plantarum, have increased shrimp growth, total hemocyte cells, granulocyte cells, and hyaline cells significantly (p < 0.05) in comparison to the control group. The supply of CNP to the water has promoted the intensity of V. parahaemolyticus effects on shrimp health and significantly decreased total hemocyte cells, granulocyte cells, and hyaline cells by 30–50% in the period after three days of the challenge, except in L. plantarum treatment, which had only a 20% decrease compared to other treatments. In CNP supplying treatments, the AHPND infected rate and mortality of shrimp were higher than those in other treatments. In summary, the supply of CNP had significantly reduced the shrimp’s immune response and promoted the susceptibility of shrimp to AHPND in both cases of use with and without LAB-containing diets.

Effects of Lactobacillus salivarius isolated from feces of fast-growing pigs on intestinal microbiota and morphology of suckling piglets

The study determined the effects of Lactobacillus salivarius (LS) administered early in the life of suckling piglets on their growth performance, gut morphology, and gut microbiota. Thirty litters of 3-day-old crossbreed piglets were randomly assigned to one of the three treatments, and treatments were commenced on day 3 after birth. During the whole period of the experiment, the piglets were kept with their mothers and left to suckle ad libitum while being supplemented with a milk formula with or without the bacterial probiotic supplemented. The control group (CON) was not treated with probiotics, the HLS group was treated with LS144 (HLS) screened from feces of fast-growing pigs with high body mass index (BMI) while the NLS group was supplemented with LS160 (NLS) screened from feces obtained from pigs of normal BMI. At the weaning time, a higher abundance of Actinobacteria, Lentisphaerae, and Elusimicrobia phyla were observed in NLS piglets, whereas the abundance of Fibrobacteres phylum was significantly reduced in NLS and HLS piglets compared with the CON. A greater abundance of Lactobacillus was detected in the HLS treatment compared with the CON. The abundance of Bacteroides and Fibrobacter was higher in the CON piglets compared with the HLS and NLS piglets. Compared with the CON group, the oral administration of LS significantly increased the number of Lactobacillus and villus height in the duodenum, jejunum, and ileum. Moreover, the villus height of the duodenum was significantly improved in the HLS treatment compared with the NLS treatment. Based on the findings in the neonatal piglet model, we suggest that oral supplementation of LS, particularly LS isolated from high BMI pigs, could be beneficial by improving the intestinal villus height.

Viral Infections, the Microbiome, and Probiotics

Viral infections continue to cause considerable morbidity and mortality around the world. Recent rises in these infections are likely due to complex and multifactorial external drivers, including climate change, the increased mobility of people and goods and rapid demographic change to name but a few. In parallel with these external factors, we are gaining a better understanding of the internal factors associated with viral immunity. Increasingly the gastrointestinal (GI) microbiome has been shown to be a significant player in the host immune system, acting as a key regulator of immunity and host defense mechanisms. An increasing body of evidence indicates that disruption of the homeostasis between the GI microbiome and the host immune system can adversely impact viral immunity. This review aims to shed light on our understanding of how host-microbiota interactions shape the immune system, including early life factors, antibiotic exposure, immunosenescence, diet and inflammatory diseases. We also discuss the evidence base for how host commensal organisms and microbiome therapeutics can impact the prevention and/or treatment of viral infections, such as viral gastroenteritis, viral hepatitis, human immunodeficiency virus (HIV), human papilloma virus (HPV), viral upper respiratory tract infections (URTI), influenza and SARS CoV-2. The interplay between the gastrointestinal microbiome, invasive viruses and host physiology is complex and yet to be fully characterized, but increasingly the evidence shows that the microbiome can have an impact on viral disease outcomes. While the current evidence base is informative, further well designed human clinical trials will be needed to fully understand the array of immunological mechanisms underlying this intricate relationship.

Experimental elucidation of an antimycobacterial bacteriocin produced by ethnomedicinal plant-derived Bacillus subtilis (MK733983)

A bacteriocin from Bacillus subtilis (MK733983) originated from ethnomedicinal plant was purified using Preparative RP-HPLC. The HPLC fraction eluted with 65% acetonitrile showed the highest antimicrobial activity with Mycobacterium smegmatis as an indicator. Its specific activity and purification fold increased by 70.5% and 44%, respectively, compared to the crude bacteriocin. The bacteriocin showed stability over a wide range of pH (3.0-8.0) and preservation (- 20 °C and 4 °C), also thermal stability up to 80 °C for 20 min. Its proteinaceous nature was confirmed with complete loss of activity on its treatment with Trypsin, Proteinase K, and α-Chymotrypsin. Nevertheless, the bacteriocin retained up to 45% activity with Papainase treatment and was unaffected by salivary Amylase. It maintained ~ 95% activity on UV exposure up to 3 h and its activity was augmented by ethyl alcohol and metal ions like Fe²⁺ and Mn²⁺. Most of the common organic solvents, general surfactants, preservatives, and detergents like Sulfobetaine-14, Deoxy-cholic-acid did not affect the bacteriocin's action. Its molecular weight was estimated to be 3.4KDa by LC-ESI-MS/MS analysis. The bacteriocin is non-hemolytic and exhibited a broad inhibition spectrum with standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and Chromobacterium violaceum with MICs ranging 0.225 ± 0.02-0.55 ± 0.05 mg/mL. Scanning Electron Microscopy showed cell annihilation with pores in cell membranes of S. aureus and P. aeruginosa treated with the bacteriocin, implicating bactericidal mode of action. These promising results suggest that the bacteriocin is significant and has wide-ranging application prospects.

Oral probiotics in coronavirus disease 2019: connecting the gut-lung axis to viral pathogenesis, inflammation, secondary infection and clinical trials

Defined as helpful live bacteria that can provide medical advantages to the host when administered in tolerable amounts, oral probiotics might be worth considering as a possible preventive or therapeutic modality to mitigate coronavirus disease 2019 (COVID-19) symptom severity. This hypothesis stems from an emerging understanding of the gut-lung axis wherein probiotic microbial species in the digestive tract can influence systemic immunity, lung immunity, and possibly viral pathogenesis and secondary infection co-morbidities. We review the principles underlying the gut-lung axis, examples of probiotic-associated antiviral activities, and current clinical trials in COVID-19 based on oral probiotics.

Kefir: A protective dietary supplementation against viral infection

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by a recently discovered coronavirus termed 'severe acute respiratory syndrome coronavirus 2' (SARS-CoV-2). Several scholars have tested antiviral drugs and compounds to overcome COVID-19. 'Kefir' is a fermented milk drink similar to a thin yogurt that is made from kefir grains. Kefir and its probiotic contents can modulate the immune system to suppress infections from viruses (e.g., Zika, hepatitis C, influenza, rotaviruses). The antiviral mechanisms of kefir involve enhancement of macrophage production, increasing phagocytosis, boosting production of cluster of differentiation-positive (CD4+), CD8+, immunoglobulin (Ig)G+ and IgA+ B cells, T cells, neutrophils, as well as cytokines (e.g., interleukin (IL)-2, IL-12, interferon gamma-γ). Kefir can act as an anti-inflammatory agent by reducing expression of IL-6, IL-1, TNF-α, and interferon-γ. Hence, kefir might be a significant inhibitor of the 'cytokine storm' that contributes to COVID-19. Here, we review several studies with a particular emphasis on the effect of kefir consumption and their microbial composition against viral infection, as well as discussing the further development of kefir as a protective supplementary dietary against SARS-CoV-2 infection via modulating the immune response.

Lacticaseibacillus paracasei DG enhances the lactoferrin anti-SARS-CoV-2 response in Caco-2 cells

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the ongoing global pandemic of coronavirus disease 2019 (COVID-19), which primarily manifests with respiratory distress and may also lead to symptoms associated with the gastrointestinal tract. Probiotics are living microorganisms that have been shown to confer immune benefits. In this study, we investigated the immunomodulatory effects and anti-SARS-CoV-2 activity of three different Lacticaseibacillus probiotic strains, either alone or in combination with lactoferrin, using the intestinal epithelial Caco-2 cell line. Our results revealed that the Lacticaseibacillus paracasei DG strain significantly induced the expression of genes involved in protective antiviral immunity and prevented the expression of proinflammatory genes triggered by SARS-CoV-2 infection. Moreover, L. paracasei DG significantly inhibited SARS-CoV-2 infection in vitro. L. paracasei DG also positively affected the antiviral immune activity of lactoferrin and significantly augmented its anti-SARS-CoV-2 activity in Caco-2 intestinal epithelial cells. Overall, our work shows that the probiotic strain L. paracasei DG is a promising candidate that exhibits prophylactic potential against SARS-CoV-2 infection.

Enterococcus faecium CMUL1216 an Immunobiotic Strain with a Potential Application in Animal Sector

Antibiotic misuse in the animal sector is the first cause of the emergence and spreading of MDR bacteria. Prevention of infectious diseases and enhancement of animal growth are the main effects of antibiotics that push farmers and veterinarians to use this molecule in animal farms. Thus, the use of alternative solutions such as natural antimicrobial substances as well as probiotic strains is a crucial need in this sector. Enterococcus faecium CMUL1216 was isolated from healthy human baby's feces. This strain was assessed in vitro for probiotic properties including activity against many pathogens isolated from animal, human, and soil samples. CMUL1216 strain exhibits good antimicrobial activity against indicator pathogens in both planktonic and biofilm forms. In addition, CMUL1216 strain showed a strong biofilm formation. Furthermore, CMUL1216 exhibits a good anti-inflammatory effect by inducing the secretion of IL-10 in vitro. Moreover, this strain did not show any pathogenic characteristics such as hemolytic effect, presence of virulence genes as well as susceptibility to the majority of antibiotic families. E. faecium CMUL1216 could be a good candidate to be used a probiotic strain in the animal sector in order to maintain animal health and therefore reduce antibiotic resistance caused by the excessive use in this sector.

Probiotics-Derived Peptides and Their Immunomodulatory Molecules Can Play a Preventive Role Against Viral Diseases Including COVID-19

As of recent, the pandemic episode of COVID-19, a severe acute respiratory syndrome brought about by a novel coronavirus (SARS-CoV-2) expanding the pace of mortality, has affected the disease rate profoundly. Invulnerability is the fundamental choice to prevent the ruining event of COVID-19, as the drugs and antibodies are in the phase of preliminary clinical trials. Within this brief period, a few strains of SARS-CoV-2 have been recognized by the vaccine manufacturers, which could be an incorrect guess about the strain that will end up spreading. Since the circulating SARS-CoV-2 strains continue to mutate, immunizations, if at all works, might be for a restricted time. We have not put sufficient time in research to understand the immune responses that correlate with protection as this could help refine vaccines. Here, we have summed up the adequacy of the immunomodulatory component of probiotics for the prevention against viral infections. Furthermore, an in silico data have been provided in support of the "probiotics-derived lipopeptides" role in inactivating spike (S) glycoprotein of SARS-CoV-2 and its host receptor molecule, ACE2. Among well characterized lipopeptides derived from different probiotic strains, subtilisin (Bacillus amyloliquefaciens), curvacin A (Lactobacillus curvatus), sakacin P (Lactobacillus sakei), lactococcin Gb (Lactococcus lactis) was utilized in this study to demonstrate a higher binding proclivity to S-protein of SARS-CoV-2 and human ACE2. The outcome revealed noteworthy capabilities of the lipopeptides, due to their amphiphilic nature, to bind spike protein and receptor molecule, which may act to competitively inhibit the mandatory interaction of SARS-CoV-2 with the host epithelial cell expressing ACE2 for its entry into the cell for reproduction. In the current situation, probiotic treatment alongside chemotherapy may assist in bringing about substantial improvement of the health of COVID-19 patients. At the same time, probiotics may aid towards building up the immune defenses in people to evade COVID-19.

Exopolysaccharides from probiotic bacteria and their health potential

Exopolysaccharides (EPS) are extracellular macromolecules excreted as tightly bound capsule or loosely attached slime layer in microorganisms. They play most prominent role against desiccation, phagocytosis, cell recognition, phage attack, antibiotics or toxic compounds and osmotic stress. In the last few decades, natural polymers have gained much attention among scientific communities owing to their therapeutic potential. In particular the EPS retrieved from probiotic bacteria with varied carbohydrate compositions possess a plenty of beneficial properties. Different probiotic microbes have unique behavior in expressing their capability to display significant health promoting characteristics in the form of polysaccharides. In this new era of alternative medicines, these polysaccharides are considered as substitutes for synthetic drugs. The EPS finds applications in various fields like textiles, cosmetics, bioremediation, food and therapeutics. The present review is focused on sources, chemical composition, biosynthetic pathways of EPS and their biological potential. More attention has been given to the scientific investigations on antimicrobial, antitumor, anti-biofilm, antiviral, anti-inflammatory and immunomodulatory activities.

The Role of the Microbiome in Oral Squamous Cell Carcinoma with Insight into the Microbiome-Treatment Axis

Oral squamous cell carcinoma (OSCC) is one of the leading presentations of head and neck cancer (HNC). The first part of this review will describe the highlights of the oral microbiome in health and normal development while demonstrating how both the oral and gut microbiome can map OSCC development, progression, treatment and the potential side effects associated with its management. We then scope the dynamics of the various microorganisms of the oral cavity, including bacteria, mycoplasma, fungi, archaea and viruses, and describe the characteristic roles they may play in OSCC development. We also highlight how the human immunodeficiency viruses (HIV) may impinge on the host microbiome and increase the burden of oral premalignant lesions and OSCC in patients with HIV. Finally, we summarise current insights into the microbiome–treatment axis pertaining to OSCC, and show how the microbiome is affected by radiotherapy, chemotherapy, immunotherapy and also how these therapies are affected by the state of the microbiome, potentially determining the success or failure of some of these treatments.

Lactic Acid Bacteria: Food Safety and Human Health Applications

Research on lactic acid bacteria has confirmed how specific strains possess probiotic properties and impart unique sensory characteristics to food products. The use of probiotic lactic acid bacteria (LAB) in many food products, thus confers various health benefits to humans when they are frequently consumed in adequate amounts. The advent of functional food or the concept of nutraceuticals objectively places more emphasis on seeking alternatives to limit the use of medications thus promoting the regular consumption of fermented foods. Probiotic use has thus been recommended to fulfill the role of nutraceuticals, as no side effects on human health have been reported. Probiotics and lactic acid bacteria can boost and strengthen the human immune system, thereby increasing its resistance against numerous disease conditions. Consumer safety and confidence in dairy and fermented food products and the desire of the food industry to meet the sensory and health needs of consumers, has thus increased the demand for probiotic starter cultures with exceptional performance coupled with health benefiting properties. The potential of probiotic cultures and lactic acid bacteria in many industrial applications including fermented food products generally affects product characteristics and also serves as health-promoting foods for humans. The alleviation of lactose intolerance in many populations globally has been one of the widely accepted health claims attributed to probiotics and lactic acid bacteria, although many diseases have been treated with probiotic lactic acid bacteria and have been proven with scientific and clinical studies. The aim of our review was to present information related to lactic acid bacteria, the new classification and perspectives on industrial applications with a special emphasis on food safety and human health.

Antibiotic activity and resistance of lactic acid bacteria and other antagonistic bacteriocin-producing microorganisms

Introduction. Increased resistance of microorganisms to traditional antibiotics has created a practical need for isolating and synthesizing new antibiotics. We aimed to study the antibiotic activity and resistance of bacteriocins produced by lactic acid bacteria and other microorganisms. Study objects and methods. We studied the isolates of the following microorganism strains: Bacillus subtilis, Penicillium glabrum, Penicillium lagena, Pseudomonas koreenis, Penicillium ochrochloron, Leuconostoc lactis, Lactobacillus plantarum, Leuconostoc mesenteroides, Pediococcus acidilactici, Leuconostoc mesenteroides, Pediococcus pentosaceus, Lactobacillus casei, Lactobacillus fermentum, Bacteroides hypermegas, Bacteroides ruminicola, Pediococcus damnosus, Bacteroides paurosaccharolyticus, Halobacillus profundi, Geobacillus stearothermophilus, and Bacillus caldotenax. Pathogenic test strains included Escherichia coli, Salmonella enterica, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus mycoides, Alcaligenes faecalis, and Proteus vulgaris. The titer of microorganisms was determined by optical density measurements at 595 nm. Results and discussion. We found that eleven microorganisms out of twenty showed high antimicrobial activity against all test strains of pathogenic and opportunistic microorganisms. All the Bacteroides strains exhibited little antimicrobial activity against Gramnegative test strains, while Halobacillus profundi had an inhibitory effect on Gram-positive species only. The Penicillium strains also displayed a slight antimicrobial effect on pathogenic test strains. Conclusion. The antibiotic resistance of the studied lactic acid bacteria and other bacteriocin-producing microorganisms allows for their use in the production of pharmaceutical antibiotic drugs.

Probiotics at War Against Viruses: What Is Missing From the Picture?

Our world is now facing a multitude of novel infectious diseases. Bacterial infections are treated with antibiotics, albeit with increasing difficulty as many of the more common causes of infection have now developed broad spectrum antimicrobial resistance. However, there is now an even greater challenge from both old and new viruses capable of causing respiratory, enteric, and urogenital infections. Reports of viruses resistant to frontline therapeutic drugs are steadily increasing and there is an urgent need to develop novel antiviral agents. Although this all makes sense, it seems rather strange that relatively little attention has been given to the antiviral capabilities of probiotics. Over the years, beneficial strains of lactic acid bacteria (LAB) have been successfully used to treat gastrointestinal, oral, and vaginal infections, and some can also effect a reduction in serum cholesterol levels. Some probiotics prevent gastrointestinal dysbiosis and, by doing so, reduce the risk of developing secondary infections. Other probiotics exhibit anti-tumor and immunomodulating properties, and in some studies, antiviral activities have been reported for probiotic bacteria and/or their metabolites. Unfortunately, the mechanistic basis of the observed beneficial effects of probiotics in countering viral infections is sometimes unclear. Interestingly, in COVID-19 patients, a clear decrease has been observed in cell numbers of Lactobacillus and Bifidobacterium spp., both of which are common sources of intestinal probiotics. The present review, specifically motivated by the need to implement effective new counters to SARS-CoV-2, focusses attention on viruses capable of co-infecting humans and other animals and specifically explores the potential of probiotic bacteria and their metabolites to intervene with the process of virus infection. The goal is to help to provide a more informed background for the planning of future probiotic-based antiviral research.

Role of probiotics to combat viral infections with emphasis on COVID-19

Interspecies transmissions of viruses between animals and humans may result in unpredictable pathogenic potential and new transmissible diseases. This mechanism has recently been exemplified by the discovery of new pathogenic viruses, such as the novel severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) pandemic, Middle-East respiratory syndrome-coronavirus epidemic in Saudi Arabia, and the deadly outbreak of Ebola in West Africa. The. SARS-CoV-2 causes coronavirus disease-19 (COVID-19), which is having a massive global impact in terms of economic disruption, and, above all, human health. The disease is characterized by dry cough, fever, fatigue, myalgia, and dyspnea. Other symptoms include headache, sore throat, rhinorrhea, and gastrointestinal disorders. Pneumonia appears to be the most common and severe manifestation of the infection. Currently, there is no vaccine or specific drug for COVID-19. Further, the development of new antiviral requires a considerable length of time and effort for drug design and validation. Therefore, repurposing the use of natural compounds can provide alternatives and can support therapy against COVID-19. In this review, we comprehensively discuss the prophylactic and supportive therapeutic role of probiotics for the management of COVID-19. In addition, the unique role of probiotics to modulate the gut microbe and assert gut homeostasis and production of interferon as an antiviral mechanism is described. Further, the regulatory role of probiotics on gut-lung axis and mucosal immune system for the potential antiviral mechanisms is reviewed and discussed.Key points• Gut microbiota role in antiviral diseases• Factors influencing the antiviral mechanism• Probiotics and Covid-19.

Probiotics and Covid-19

Coronavirus disease 2019 (COVID-19) has become pandemic very rapidly at the beginning of 2020. In the rush to possible therapeutic options, probiotics administration has been proposed mainly based on indirect observation. Some evidence of COVID-19 effects on intestinal microbiota dysbiosis has been shown and probiotics have been considered for their efficacy in the management of respiratory tract viral infections. These observations could be reinforced by the more and more evident existence of a lung-gut axis, suggesting the modulation of gut microbiota among the approaches to the COVID-19 prevention and treatment. As different possible roles of probiotics in this extremely severe illness have been contemplated, the aim of this work is to collect all the currently available information related to this topic, providing a starting point for future studies focussing on it.

Antiviral Activity of Fecal Water Samples from HIV-1 Infected Subjects Treated with a Specific Probiotic Formulation

OBJECTIVES

The aim of the study was to investigate if the supplementation with multistrain probiotics may be able to modulate T cell response in HIV-1 infected patients and to evaluate the anti-HIV activity of probiotic by studying fecal water (FW) samples.

METHODS

Three HIV-1-positive patients (Pt1, Pt2 and Pt3) on long-term suppressive combined antiretroviral therapy (cART) received a specific multi-strain probiotic supplementation (Vivomixx ®), for six months (T6). Levels of T cell subsets were evaluated by flow cytometry. Anti- HIV activity of FW samples was evaluated in vitro.

RESULTS

CD4+ T cells levels increased in all HIV-1 infected patients whereas activation markers (CD38 and HLA-DR) were decreased both on CD4+ and CD8+ T cells. FW samples presented an increased inhibitory activity against HIV-1 compared to T0 (FW-Pt1: T0 =40%, T6 = 65% of reduction; FW Pt2: T0 = 26%, T6 = 46% of reduction; FW Pt3: T0 = 47%, T6 = 94% of reduction).

DISCUSSION

Our data suggest that the administration of the specific probiotic formulation improves the antiviral status of people living with HIV-1 under cART, also modulating T cell response.

CONCLUSION

Anti-HIV activity of FW may have several public health and social implications for sexually transmitted diseases that need to be further explored.

Isolation of a Leuconostoc mesenteroides Strain With Anti-Porcine Epidemic Diarrhea Virus Activities From Kefir Grains

Swine grown under commercial conditions are vulnerable to environmental exposure to several viruses, which may cause infectious diseases and spread easily and rapidly, resulting in significant economic losses in animal husbandry. Previous studies have suggested that probiotics seem to be a new and promising alternative to vaccinations to protect animals against potential viral infections. In this study, we used the Vero cell culture model of infection to study porcine epidemic diarrhea virus (PEDV). We screened lactic acid bacteria (LAB) with anti-PEDV potential from kefir grains, which are starter cultures used to ferment milk into kefir. Twenty-nine LAB strains were isolated and identified as Enterococcus durans, Lactobacillus kefiri, Lactococcus lactis, and Leuconostoc mesenteroides, according to 16S ribosomal RNA (rRNA) and rpoA gene sequence analyses. The anti-PEDV activities of the LAB intracellular extracts were compared, and the intracellular extracts of Ln. mesenteroides showed higher anti-PEDV activities than that of the other species. Among the Ln. mesenteroides strains, a strain designated YPK30 showed a higher growth rate than that of the other strains and was further evaluated for its anti-PEDV activity. The results showed that the intracellular extracts of Ln. mesenteroides YPK30 possessed in vitro prophylactic, therapeutic, and direct-inhibitory effects against PEDV in the Vero cell model. The expression levels of Type 1 interferon (IFN)-dependent genes, including Myxovirus resistance 1 (MX1) and interferon-stimulated gene 15 (ISG15), were significantly increased after treatment with intracellular extracts of Ln. mesenteroides YPK30 for 24 h. Such expression suggests that the anti-PEDV activity of Ln. mesenteroides YPK30 could be attributed to its up-regulatory effect on the expression of MX1 and ISG15 genes. These results suggested that Ln. mesenteroides YPK30 has the potential to provide some levels of host protection against PEDV infections.

Comparative analysis of the gut microbiota of Apis cerana in Yunnan using high-throughput sequencing

Gut microbes play an important role in host disease and health. The Asian honey bee Apis cerana is an important pollinator of agricultural crops in China. However, there are still few studies on the structure and composition of the microbiota in the intestine of A. cerana, especially A. cerana in Yunnan. To understand the species and composition of the microbiota in the intestine of A. cerana in Yunnan, we used high-throughput sequencing technology to carry out 16S rRNA sequencing on 50 samples from Kunming, Xishuangbanna and Mengzi. The results show that both from the phylum level and the genus level, the structure and abundance of the microbiota in the gut of A. cerana from the three regions tended to be the same. At the phylum level, the abundance of Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Acidobacteria and other species was high in A. cerana from different areas. At the genus level, the abundance of Lactobacillus, Gilliamella, Snodgrassella, Apibacter, Candidatus Schmidhempelia and other species was high in A. cerana from different areas. Due to its unique geographical environment and climatic conditions, at the genus level, the diversity of bacterial communities in Xishuangbanna was significantly lower than that in the other two regions, which was about 100 genera less. In conclusion, our results reveal the composition and structure of the intestinal microbiota of bees in Yunnan and deepen our understanding of the intestinal microbiota of bees.

Surface-Displayed Porcine IFN-λ3 in Lactobacillus plantarum Inhibits Porcine Enteric Coronavirus Infection of Porcine Intestinal Epithelial Cells

Interferon (IFN)-λ plays an essential role in mucosal cells which exhibit strong antiviral activity. Lactobacillus plantarum (L. plantarum) has substantial application potential in the food and medical industries because of its probiotic properties. Alphacoronaviruses, especially porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis virus (TGEV), cause high morbidity and mortality in piglets resulting in economic loss. Co-infection by these two viruses is becoming increasingly frequent. Therefore, it is particularly important to develop a new drug to prevent diarrhea infected with mixed viruses in piglets. In this study, we first constructed an anchored expression vector with CWA (C-terminal cell wall anchor) on L. plantarum. Second, we constructed two recombinant L. plantarum strains that anchored IFN-λ3 via pgsA (N-terminal transmembrane anchor) and CWA. Third, we demonstrated that both recombinant strains possess strong antiviral effects against coronavirus infection in the intestinal porcine epithelial cell line J2 (IPEC-J2). However, recombinant L. plantarum with the CWA anchor exhibited a more powerful antiviral effect than recombinant L. plantarum with pgsA. Consistent with this finding, Lb.plantarum-pSIP-409-IFN-λ3-CWA enhanced the expression levels of IFN-stimulated genes (ISGs) (ISG15, OASL, and Mx1) in IPEC-J2 cells more than did recombinant Lb.plantarum-pSIP-409-pgsA'-IFN-λ3. Our study verifies that recombinant L. plantarum inhibits PEDV and TGEV infection in IPEC-J2 cells, which may offer great potential for use as a novel oral antiviral agent in therapeutic applications for combating porcine epidemic diarrhea and transmissible gastroenteritis. This study is the first to show that recombinant L. plantarum suppresses PEDV and TGEV infection of IPEC-J2 cells.

Anti-Influenza Activity of Enterocin B In vitro and Protective Effect of Bacteriocinogenic Enterococcal Probiotic Strain on Influenza Infection in Mouse Model

In spite of scientific evidence demonstrating the antiviral activity of lactic-acids bacteria, little is known about the mechanism of their action. Previously, several bacteriocins isolated from lactic acid bacteria (LAB) and some other microorganisms were reported as having antiviral activity in vitro. In the present study, chemically synthetized enterocin B (EntB) and the strain E. faecium L3, known as the producer of this peptide, were tested for activity against influenza viruses. The inhibition of cytopathic effect of А/Perth/16/2009(H3N2) and A/South Africa/3626/2013(H1N1) pdm influenza viruses in MDCK cells by chemically synthetized EntB was revealed. The EntB demonstrated antiviral activity at a concentration of 2.5-5 μg/ml depending on the dose of viruses. This peptide exhibited low toxicity in MDCK cells, causing partial damage of the monolayer of the cells only at a concentration above 10 μg/ml. It was also shown, that strain E. faecium L3-protected mice from lethal A/South Africa/3626/2013(H1N1) pdm infection. We speculate that this protective effect of enterococci may be associated with the specific action of enterocin B, which possesses antiviral activity in vitro.

Nutraceuticals as modulators of gut microbiota: Role in therapy

As our knowledge of the various roles of the gut microbiota in the maintenance of homeostasis grows and as we learn how a disrupted microbiota may contribute to disease, therapeutic strategies that target our microbial fellow-travellers become ever more attractive. Most appealing are those interventions that seek to modify or supplement our diet through the addition of nutraceuticals. We now know that our diet, whether in the short or long term, is a major modifier of microbiota composition and function. Of the various nutraceuticals, two categories, prebiotics and probiotics, have received the greatest attention in basic research and product development. While our understanding of the impacts of prebiotics and probiotics on the indigenous microbiota and host biology have been described in great detail in vitro and in animal models, the clinical literature leaves much to be desired. While many claims have been made, few are supported by high quality clinical trials. LINKED ARTICLES: This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc.

Probiotic Lactobacillus and Bifidobacterium strains possess safety characteristics, antiviral activities and host adherence factors revealed by genome mining

Background

Probiotics belonging to Lactobacillus and Bifidobacterium spp. have been exploited for their health benefits in treatment and prevention of many pathological conditions and promoting human health. Recent advances in understanding probiotics-human interaction through microbiome research in the context of various medical conditions suggest their provisional role in preventive, personalized, and predictive medicine. To streamline their application in disease prevention, development of personalized-based treatments, or their use as biomarkers for predictive diagnosis, in vitro screening for strains with potential probiotic properties should be performed. In this work, we aimed to emphasize the probiotic features of four Lactobacillus and two Bifidobacterium probiotic strains which showed antagonistic properties against microbial pathogens.

Methods

Firstly, cytotoxicity assessment of cell-free preparations from these strains was performed using a baby hamster kidney (BHK) cells and cell viability was measured by means of sulfo-rhodamine B stain. Secondly, Newcastle disease (ND) and infectious bursal disease (IBD) viruses which pose a great threat in infected poultry were used for assessing antiviral activity of probiotics. Thirdly, the genomes of six probiotic strains were used to identify genes encoding host adherence factors that mediate interaction with human tissues.

Results

Probiotic preparations exhibited insignificant toxicity as indicated by the high survival rate of BHK cells (surviving fraction varied from 0.82 to 0.99) as compared to the untreated control. Cell-free preparations of probiotics mixed with equal volume of ND and IBD viruses (10⁶ and 10⁴ Tissue Culture Infectious Dose 50, respectively) reduced the titer of ND and IBD viruses on chicken embryo fibroblast cells. Genome mining analysis revealed that the draft genomes of these strains were predicted to encode LPXTG-containing proteins, surface layer proteins, tight adherence pili, sortase-dependent pili, fibronectin, or collagen binding proteins and other factors that adhere to human tissues such as mucus. Such adherence factors enable probiotic bacteria to interact and colonize the host.

Conclusion

Taken together, safety privileges, antiviral activities, and genomically encoded host interaction factors confirmed probiotic features of the six probiotic strains and their potential in promoting human health.

Antiviral Activity of Exopolysaccharides Produced by Lactic Acid Bacteria of the Genera Pediococcus, Leuconostoc and Lactobacillus against Human Adenovirus Type 5

Background and objectives: The use of antagonistic probiotic microorganisms and their byproducts represents a promising approach for the treatment of viral diseases. In the current work, the effect of exopolysaccharides (EPSs) produced by lactic acid bacteria from different genera on the structural and functional characteristics of cells and the development of adenoviral infection in vitro was studied. Materials and Methods: Cytotoxicity of six EPSs of lactic acid bacteria of the genera Lactobacillus, Leuconostoc and Pediococcus was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The influence of the EPSs on the infectivity of human adenovirus type 5 (HAdV-5) and on the cell cycle under a condition of adenovirus infection was studied using plaque reduction assay and flow cytometric analysis, respectively. Results: It was shown that exopolysaccharides were non-toxic to Madin-Darby bovine kidney cells (MDBK) as they reduced their viability by 3-17%. A change in the distribution of the cell cycle phases in the non-infected cell population treated with EPSs was observed. The analysis demonstrated an increase in the number of cells in the S phase by 47% when using EPSs 15a and a decrease in the number of cells in the G1 phase by 20-27% when treated with the EPSs 15a, 33a, and 19s. The use of EPSs did not led to the normalization of the life cycle of HAdV-5 infected cells to the level of non-infected cells. The EPSs showed low virucidal activity and reduced the HAdV-5 infectivity to 85%. Among the studied exopolysaccharides, anti-adenovirus activity was found for EPS 26a that is produced by Lactobacillus spp. strain. The treatment of cells with the EPS following virus adsorption completely (100%) suppressed the formation and release of HAdV-5 infectious. Conclusions: EPS 26a possessed distinct anti-HAdV-5 activity and the obtained data demonstrate the potential of using exopolysaccharides as anti-adenoviral agents.

Recombinant lactococcus lactis secreting viral protein 1 of enterovirus 71 and its immunogenicity in mice

OBJECTIVE

To construct recombinant Lactococcus lactis (L. lactis) expressing viral protein 1 (VP1) of enterovirus 71 (EV71) and evaluate its immunogenicity to be used as an oral vaccine in BALB/c mice.

RESULTS

Recombinant L. lactis competent in secreting VP1 (~ 30 kDa) into the extracellular environment with the aid of the signal peptide Usp45 was produced. Enzyme-linked immunosorbent assay showed that significant VP1-specific antibody response including the production of both serum IgG and fecal IgA (p < 0.05) was elicited in BALB/c mice upon oral immunization with recombinant L. lactis. Moreover, in contrast to negative control, recombinant L. lactis induced adequate neutralizing antibodies in mouse sera (p < 0.05) as demonstrated in virus neutralization assay, whereas the presence of neutralizing antibodies in fecal samples was obvious but not significant (p > 0.05).

CONCLUSIONS

Recombinant L. lactis expressing VP1 of EV71 has the potential to be used as an oral vaccine candidate. The findings may provide some preliminary evidences for further development of effective and needle-free EV71 vaccines.

Bacteriocins of Gram-positive bacteria having activity spectra extending beyond closely-related species

Bacteriocins are bacterially-produced antimicrobial peptides that have killing activity principally against other relatively closely-related bacteria. Some bacteriocins of the lactic acid bacteria (LAB) have for many years been extensively applied in food biopreservation. However, especially during the last decade, a number of reports have appeared about unanticipated extensions to the generally rather narrow anti-bacterial activity spectrum of some of the LAB bacteriocins and novel applications have been proposed for bacteriocins ranging from controlling the growth of an increasingly-heterogeneous variety of pathogens, including Gram-negative multidrug resistant bacteria, viruses, yeasts, and in particular, difficult to control Mycobacterium spp., to their potential application as anticancer agents. How best can we assess this now rapidly-accumulating stream of reports on potential future applications of bacteriocins? Where is the line between realistic, science-based proposals and highly-speculative fiction and what are the ‘critical points’ that might help us to draw this line? In this review, we have attempted to analyse a selection of the presently-available data concerning relatively ‘unorthodox’ (i.e. beyond food preservation) applications of bacteriocins, and, by utilising our set of ‘critical points’, we endeavour to identify essential or/and missing information that appear crucial for success of the proposed applications.

Benefits and Inputs From Lactic Acid Bacteria and Their Bacteriocins as Alternatives to Antibiotic Growth Promoters During Food-Animal Production

Resistance to antibiotics is escalating and threatening humans and animals worldwide. Different countries have legislated or promoted the ban of antibiotics as growth promoters in livestock and aquaculture to reduce this phenomenon. Therefore, to improve animal growth and reproduction performance and to control multiple bacterial infections, there is a potential to use probiotics as non-antibiotic growth promoters. Lactic acid bacteria (LAB) offer various advantages as potential probiotics and can be considered as alternatives to antibiotics during food-animal production. LAB are safe microorganisms with abilities to produce different inhibitory compounds such as bacteriocins, organic acids as lactic acid, hydrogen peroxide, diacetyl, and carbon dioxide. LAB can inhibit harmful microorganisms with their arsenal, or through competitive exclusion mechanism based on competition for binding sites and nutrients. LAB endowed with specific enzymatic functions (amylase, protease…) can improve nutrients acquisition as well as animal immune system stimulation. This review aimed at underlining the benefits and inputs from LAB as potential alternatives to antibiotics in poultry, pigs, ruminants, and aquaculture production.

Effectiveness of the probiotic Streptococcus salivarius K12 for the treatment and/or prevention of sore throat: a systematic review

BACKGROUND

Sore throat resulting from pharyngotonsillitis is one of the commonest reasons for primary care consultation and inappropriate antibiotic prescription and finding effective alternative treatments is important.

OBJECTIVES

To review the evidence for using the probiotic Streptococcus salivarius K12 (SsK12) for the prevention or treatment of pharyngotonsillitis.

DATA SOURCES

PubMed, Embase, CINAHL and Cochrane Library.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials (RCTs).

PARTICIPANTS

Adults or children.

INTERVENTIONS

SsK12 as active treatment or prophylaxis, against pharyngotonsillitis.

METHODS

Literature search.

RESULTS

Four articles were identified (1846 participants). All were deemed to be of poor quality using the Cochrane risk-of-bias assessment. Two trials studied SsK12 prophylaxis for streptococcal pharyngitis (children without history of recurrence). One compared daily administration of SsK12 to no treatment over 6 months (n = 222, age 33-45 months), reporting significantly lower incidence in the SsK12 group (16.2% vs. 48.6%, p < 0.01), whereas another placebo-controlled RCT over four school terms (n = 1314, 5-14 years) found no significant difference (7.8% vs. 8.8%, p 0.34) with SsK12 (administered on school days). Another trial found daily SsK12 to significantly protect children (n = 250, 6-7 years) against chronic adenoiditis exacerbation over 3 months compared to no treatment (71.7% vs. 100%, p < 0.0001). The one placebo-controlled RCT in adults that studied the use of SsK12 for acute pharyngotonsillitis (concurrently with penicillin) showed no significant benefit. In all trials, SsK12 was safe and well tolerated.

CONCLUSIONS

SsK12 appears safe and well tolerated. However, further RCTs are required to establish its role as a prophylactic therapy, particularly among patients experiencing frequent exacerbations of pharyngitis. In the acute setting, SsK12 is unlikely to be effective if given concurrently with antibiotics; however, further RCTs should establish its role as an alternative to antibiotics in nonsevere cases or when prescribed after antibiotic therapy for the prevention of disease recurrence and/or secondary infection.

Lactobacillus delbrueckii subsp. bulgaricus F17 and Leuconostoc lactis H52 supernatants delay the decay of strawberry fruits: a microbiome perspective

Lactobacillus delbrueckii subsp. bulgaricus F17 and Leuconostoc lactis H52 as the potential biopreservative, which delayed the decay and changed the structure of microbial community of the ‘Benihoppe’ strawberry fruits.

Systemic immune response of gnotobiotic mice infected with porcine circovirus type 2 after administration of Lactobacillus reuteri L26 Biocenol™

In our previous study we confirmed an antiviral activity of probiotic Lactobacillus reuteri L26 which was mediated by stimulation of local intestinal immunity. The aim of this paper was to evaluate the influence of L. reuteri L26 on the systemic immune response in gnotobiotic mice infected with porcine circovirus type 2 (PCV2). A total of 30 germ-free mice were divided into 3 groups and animals in noninfected and infected control groups (NC and IC; n=10) received sterile de Man-Rogosa-Sharpe broth for 7 days and animals in experimental group L+PCV (n=10) were inoculated with L. reuteri L26. Subsequently, mice in L+PCV and IC groups were infected with PCV2; however, mice in the control group received virus cultivation medium (mock). The results showed an increase of percentage of cytotoxic cells (CD8+ and CD49b+CD8-) and oxidative burst of phagocytes, up-regulation of the gene expression of RANTES, granulocyte-macrophage colony-stimulating factor, interferon-γ and immunoglobulin A in blood above all in the later phase of infection (14 dpi) in L+PCV group accompanied by higher load of PCV2 in the serum. These findings indicate that L. reuteri L26 has a potential to induce systemic immune reaction, but in gnotobiotic mice immune stimulation can increase virus replication.

Foodborne viruses: Detection, risk assessment, and control options in food processing

In a recent report by risk assessment experts on the identification of food safety priorities using the Delphi technique, foodborne viruses were recognized among the top rated food safety priorities and have become a greater concern to the food industry over the past few years. Food safety experts agreed that control measures for viruses throughout the food chain are required. However, much still needs to be understood with regard to the effectiveness of these controls and how to properly validate their performance, whether it is personal hygiene of food handlers or the effects of processing of at risk foods or the interpretation and action required on positive virus test result. This manuscript provides a description of foodborne viruses and their characteristics, their responses to stress and technologies developed for viral detection and control. In addition, the gaps in knowledge and understanding, and future perspectives on the application of viral detection and control strategies for the food industry, along with suggestions on how the food industry could implement effective control strategies for viruses in foods. The current state of the science on epidemiology, public health burden, risk assessment and management options for viruses in food processing environments will be highlighted in this review.