Cell free preparations of probiotics exerted antibacterial and antibiofilm activities against multidrug resistant E. coli

Therapeutic Potential of Cinnamon Oil: Chemical Composition, Pharmacological Actions, and Applications

Cinnamon oil, an essential oil extracted from plants of the genus Cinnamomum, has been highly valued in ancient Chinese texts for its medicinal properties. This review summarizes the chemical composition, pharmacological actions, and various applications of cinnamon oil, highlighting its potential in medical and industrial fields. By systematically searching and evaluating studies from major scientific databases including Web of Science, PubMed, and ScienceDirect, we provide a comprehensive analysis of the therapeutic potential of cinnamon oil. Research indicates that cinnamon oil possesses a wide range of pharmacological activities, covering antibacterial, anti-inflammatory, anti-tumor, and hypoglycemic effects. It is currently an active ingredient in over 500 patented medicines. Cinnamon oil has demonstrated significant inhibitory effects against various pathogens comprising Staphylococcus aureus, Salmonella, and Escherichia coli. Its mechanisms of action include disrupting cell membranes, inhibiting ATPase activity, and preventing biofilm formation, suggesting its potential as a natural antimicrobial agent. Its anti-inflammatory properties are evidenced by its ability to suppress inflammatory markers like vascular cell adhesion molecules and macrophage colony-stimulating factors. Moreover, cinnamon oil has shown positive effects in lowering blood pressure and improving metabolism in diabetic patients by enhancing glucose uptake and increasing insulin sensitivity. The main active components of cinnamon oil include cinnamaldehyde, cinnamic acid, and eugenol, which play key roles in its pharmacological effects. Recently, the applications of cinnamon oil in industrial fields, including food preservation, cosmetics, and fragrances, have also become increasingly widespread. Despite the extensive research supporting its medicinal value, more clinical trials are needed to determine the optimal dosage, administration routes, and possible side effects of cinnamon oil. Additionally, exploring the interactions between cinnamon oil and other drugs, as well as its safety in different populations, is crucial. Considering the current increase in antibiotic resistance and the demand for sustainable and effective medical treatments, this review emphasizes the necessity for further research into the mechanisms and safety of cinnamon oil to confirm its feasibility as a basis for new drug development. In summary, as a versatile natural product, cinnamon oil holds broad application prospects and is expected to play a greater role in future medical research and clinical practice.

Lactic acid bacteria isolated from women' breast milk and infants' faeces have appreciable immunogenic and probiotic potentials against diarrheagenic E. coli strains

Diarrheal diseases remain the leading cause of high mortality among the infants, particularly in the developing countries; Probiotic intervention for diarrhea has been an ongoing novel approach to diarrheal prevention and treatment. This study aims to characterize immunogenic and probiotic properties of lactic acid bacteria (LAB) isolated from human breast milk and neonates' faeces. The LAB isolates from 16 mothers' breast milk and 13 infants' faeces were screened and identified by 16 S rRNA gene partial sequencing. Their antimicrobial activities against 5 strains of diarrheagenic Escherichia coli were tested. Organic acids production was quantified by HPLC, and antibiotic resistance pattern were determined by VITEK®. Autoaggregation, co-aggregation and hydrophobicity properties were assessed by UV spectrophotometry and immunomodulatory effect was determined in mouse model. Ninety-three LAB of five genera were identified. The most abundant species was Lactiplantibacillus plantarum with inhibition zones ranged from 8.0 to 25.0 ± 1 mm. Lacticaseibacillus rhamnosus A012 had 76.8 mg/mL lactic acid, (the highest concentration), was susceptible to all antibiotics tested. L. plantarum A011 and L. rhamnosus A012 were highly resistance to gastrointestinal conditions. L. rhamnosus A012 produced hydrophobicity of 25.01% (n-hexadecane), 15.4% (xylene) and its autoaggregation was 32.52%. L. rhamnosus A012 and L. plantarum A011 exert immunomodulatory effects on the cyclophosphamide-treated mice by upregulating anti-inflammatory cytokine and downregulating proinflammatory cytokines. Lactobacillus sp. demonstrated good probiotic and immunomodulatory properties. Further works are ongoing on the practical use of the strains.

Analysis of Gut Bacterial and Fungal Microbiota in Children with Autism Spectrum Disorder and Their Non-Autistic Siblings

Autism Spectrum Disorder (ASD) is a multifactorial disorder involving genetic and environmental factors leading to pathophysiologic symptoms and comorbidities including neurodevelopmental disorders, anxiety, immune dysregulation, and gastrointestinal (GI) abnormalities. Abnormal intestinal permeability has been reported among ASD patients and it is well established that disturbances in eating patterns may cause gut microbiome imbalance (i.e., dysbiosis). Therefore, studies focusing on the potential relationship between gut microbiota and ASD are emerging. We compared the intestinal bacteriome and mycobiome of a cohort of ASD subjects with their non-ASD siblings. Differences between ASD and non-ASD subjects include a significant decrease at the phylum level in Cyanobacteria (0.015% vs. 0.074%, p < 0.0003), and a significant decrease at the genus level in Bacteroides (28.3% vs. 36.8%, p < 0.03). Species-level analysis showed a significant decrease in Faecalibacterium prausnitzii, Prevotella copri, Bacteroides fragilis, and Akkermansia municiphila. Mycobiome analysis showed an increase in the fungal Ascomycota phylum (98.3% vs. 94%, p < 0.047) and an increase in Candida albicans (27.1% vs. 13.2%, p < 0.055). Multivariate analysis showed that organisms from the genus Delftia were predictive of an increased odds ratio of ASD, whereas decreases at the phylum level in Cyanobacteria and at the genus level in Azospirillum were associated with an increased odds ratio of ASD. We screened 24 probiotic organisms to identify strains that could alter the growth patterns of organisms identified as elevated within ASD subject samples. In a preliminary in vivo preclinical test, we challenged wild-type Balb/c mice with Delftia acidovorans (increased in ASD subjects) by oral gavage and compared changes in behavioral patterns to sham-treated controls. An in vitro biofilm assay was used to determine the ability of potentially beneficial microorganisms to alter the biofilm-forming patterns of Delftia acidovorans, as well as their ability to break down fiber. Downregulation of cyanobacteria (generally beneficial for inflammation and wound healing) combined with an increase in biofilm-forming species such as D. acidovorans suggests that ASD-related GI symptoms may result from decreases in beneficial organisms with a concomitant increase in potential pathogens, and that beneficial probiotics can be identified that counteract these changes.

Vibriocidal efficacy of Bifidobacterium bifidum and Lactobacillus acidophilus cell-free supernatants encapsulated in chitosan nanoparticles against multi-drug resistant Vibrio cholerae O1 El Tor

BACKGROUND

Cholera is a diarrheal disease recognized for being caused by toxin-producing Vibrio (V.) cholerae. This study aims to assess the vibriocidal and immunomodulatory properties of derived cell-free supernatants (CFSs) of Bifidobacterium (B.) bifidum and Lactobacillus (L.) acidophilus encapsulated in chitosan nanoparticles (CFSb-CsNPs and CFSa-CsNPs) against clinical multi-drug resistance (MDR) isolates of V. cholerae O1 El Tor.

METHODS

We synthesized CFSb-CsNPs and CFSa-CsNPs using the ionic gelation technique. The newly nanostructures were characterized for size, surface zeta potential, morphology, encapsulation efficacy (EE), stability in different pH values and temperatures, release profile, and in vitro cytotoxicity. The antimicrobial and antibiofilm effects of the obtained nanocomposites on clinical MDR isolates (N = 5) of V. cholerae E1 Tor O1 were investigated by microbroth dilution assay and crystal violet staining, respectively. We conducted quantitative real-time PCR (qRT-PCR) to analyze the relative gene expressions of Bap, Rbmc, CTXAB, and TCP in response to CFSb-CsNPs and CFSa-CsNPs. Additionally, the immunomodulatory effects of formulated structures on the expression of TLR2 and TLR4 genes in human colorectal adenocarcinoma cells (Caco-2) were studied.

RESULTS

Nano-characterization analyses indicated that CFSb-CsNPs and CFSa-CsNPs exhibit spherical shapes under scanning electron microscopy (SEM) imaging, with mean diameters of 98.16 ± 0.763 nm and 83.90 ± 0.854 nm, respectively. Both types of nanoparticles possess positive surface charges. The EE% of CFSb-CsNPs was 77 ± 4.28%, whereas that of CFSa-CsNPs was 62.5 ± 7.33%. Chitosan (Cs) encapsulation leads to increased stability of CFSs in simulated pH conditions of the gastrointestinal tract in which the release rates for CFSb-CsNPs and CFSa-CsNPs were reached at 58.00 ± 1.24% and 55.01 ± 1.73%, respectively at pH = 7.4. The synergistic vibriocidal effects observed from the co-administration of both CFSb-CsNPs and CFSa-CsNPs, as evidenced by a fractional inhibitory concentration (FIC) index of 0.57, resulting in a significantly lower MIC of 2.5 ± 0.05 mg/mL (p < 0.0001) compare to individual administration. The combined antibacterial effect of CFSb-CsNPs and CFSa-CsNPs on Bap (0.14 ± 0.05), Rbmc (0.24 ± 0.01), CTXAB (0.30 ± 0.09), and TCP (0.38 ± 0.01) gene expression was significant (p < 0.001). Furthermore, co-administration of CFSb-CsNPs and CFSa-CsNPs also demonstrated the potency of suppressing TLR 2/4 (0.20 ± 0.01 and 0.12 ± 0.02, respectively) gene expression (p = 0.0019) and reduced Caco-2 cells attached bacteria to 526,000 ± 51,46 colony-forming units/mL (11.19%) (p < 0.0001).

CONCLUSION

Our study revealed that encapsulating CFSs within CsNPs enhances their vibriocidal activity by improving stability and enabling a controlled release mechanism at the site of interaction between the host and bacteria. Additionally, the simultaneous use of CFSb-CsNPs and CFSa-CsNPs exhibited superior vibriocidal potency against MDR V. cholerae O1 El Tor strains, indicating these combinations as a potential new approach against MDR bacteria.

Safety assessment of probiotic Lactiplantibacillus plantarum MCC5231 and its persistence in gastrointestinal tract

Probiotics are the health beneficial microorganisms and suitable for food industry if found fit for human consumption. In the present study, Lactiplantibacillus plantarum MCC5231, a probiotic bacterium included in vegetable-based beverages, was evaluated for its safety characteristics and gastrointestinal survival using a combined in silico and in vitro approach. The strain was found to be devoid of hemolytic, lecithinase and gelatinase activities. Additionally, it does not consist any transferable antibiotic resistance genes. Further, whole genome sequence analysis revealed the presence of three intact prophages and 14 virulence-associated genes, however, none of them posed a pathogenic threat. Importantly, MCC5231 do not possess any gene associated with toxin production. The strain harbored a CRISPR system, enhancing defense against prophages. Survival assays under simulated gastric and intestinal fluid conditions demonstrated viability rates of 71.4 % and 83.3 %, respectively. Genetic analysis of the mucin binding protein indicated possession of a type II mucin binding domain, suggesting moderate adhesion to intestinal cells. Furthermore, L. plantarum MCC5231 exhibited the ability to produce exopolysaccharides and form biofilms, which may confer additional protection in the gastrointestinal tract. Based on these findings, L. plantarum MCC5231 appears to be a safe probiotic candidate suitable for commercial use in the food industry.

Postbiotics Implication in the Microbiota-Host Intestinal Epithelial Cells Mutualism

To sustain host health and provide the microbial community with a nutrient-rich environment, the host and gut microbiota must interact with one another. These interactions between commensal bacterial and intestinal epithelial cells (IECs) serve as the first line of defense against gut microbiota in preserving intestinal homeostasis. In this microenvironment, the post-biotics and similar molecules such as p40 exert several beneficial effects through regulation of IECs. Importantly, post-biotics were discovered to be transactivators of the EGF receptor (EGFR) in IECs, inducing protective cellular responses and alleviating colitis. The transient exposure to post-biotics such as p40 during the neonatal period reprograms IECs by upregulation of a methyltransferase, Setd1β, leading to a sustained increase in TGF- β release for the expansion of regulatory T cells (Tregs) in the intestinal lamina propria and durable protection against colitis in adulthood. This crosstalk between the IECs and post-biotic secreted factors was not reviewed previously. Therefore, this review describes the role of probiotic-derived factors in the sustainability of intestinal health and improving gut homeostasis via certain signaling pathways. In the era of precision medicine and targeted therapies, more basic, preclinical, and clinical evidence is needed to clarify the efficacy of probiotics released as functional factors in maintaining intestinal health and preventing and treating disease.

Surface-enhanced Raman spectroscopy for studying the interaction of organometallic compound bis(1,3-dihexylimidazole-2-yl) silver(i) hexafluorophosphate (v) with the biofilm of Escherichia coli

Escherichia coli biofilms are a major cause of gastrointestinal tract diseases, such as esophageal, stomach and intestinal diseases. Nowadays, these are the most commonly occurring diseases caused by consuming contaminated food. In this study, we evaluated the efficacy of probiotics in controlling multidrug-resistant E. coli and reducing its ability to form biofilms. Our results substantiate the effective use of probiotics as antimicrobial alternatives and to eradicate biofilms formed by multidrug-resistant E. coli. In this research, surface enhanced Raman spectroscopy (SERS) was utilized to identify and evaluate Escherichia coli biofilms and their response to the varying concentrations of the organometallic compound bis(1,3-dihexylimidazole-2-yl) silver(i) hexafluorophosphate (v). Given the escalating challenge of antibiotic resistance in bacteria that form biofilms, understanding the impact of potential antibiotic agents is crucial for the healthcare sector. The combination of SERS with principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) enabled the detection and characterization of the biofilm, providing insights into the biochemical changes induced by the antibiotic candidate. The identified SERS spectral features served as indicators for elucidating the mode of action of the potential drug on the biofilm. Through PCA and PLS-DA, metabolic variations allowing the differentiation and classification of unexposed biofilms and biofilms exposed to different concentrations of the synthesized antibiotic were successfully identified, with 95% specificity, 96% sensitivity, and a 0.75 area under the curve (AUC). This research underscores the efficiency of surface enhanced Raman spectroscopy in differentiating the impact of potential antibiotic agents on E. coli biofilms.

Saccharomyces cerevisiae derived postbiotic alters gut microbiome metabolism in the human distal colon resulting in immunomodulatory potential in vitro

The yeast-based postbiotic EpiCor is a well-studied formulation, consisting of a complex mixture of bioactive molecules. In clinical studies, EpiCor postbiotic has been shown to reduce intestinal symptoms in a constipated population and support mucosal defense in healthy subjects. Anti-inflammatory potential and butyrogenic properties have been reported in vitro, suggesting a possible link between EpiCor's gut modulatory activity and immunomodulation. The current study used a standardized in vitro gut model, the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), to obtain a deeper understanding on host-microbiome interactions and potential microbiome modulation following repeated EpiCor administration. It was observed that EpiCor induced a functional shift in carbohydrate fermentation patterns in the proximal colon environment. Epicor promoted an increased abundance of Bifidobacterium in both the proximal and distal colon, affecting overall microbial community structure. Co-occurrence network analysis at the phylum level provided additional evidence of changes in the functional properties of microbial community promoted by EpiCor, increasing positive associations between Actinobacteria with microbes belonging to the Firmicutes phylum. These results, together with a significant increase in butyrate production provide additional support of EpiCor benefits to gut health. Investigation of host-microbiome interactions confirmed the immunomodulatory potential of the applied test product. Specific microbial alterations were observed in the distal colon, with metabotyping indicating that specific metabolic pathways, such as bile acid and tryptophan metabolism, were affected following EpiCor supplementation. These results, especially considering many effects were seen distally, further strengthen the position of EpiCor as a postbiotic with health promoting functionality in the gut, which could be further assessed in vivo.

Probiotic Lactobacillus plantarum Ln4 Showing Antimicrobial and Antibiofilm Effect against Streptococcus mutans KCTC 5124 Causing Dental Caries

Dental caries has known as an infectious disease that is considered a serious global public health problem. Recently, report indicate that probiotics play a vital role in maintaining oral health. Therefore, this study aimed to evaluate the prevention effects of Lactobacillus plantarum Ln4 against dental infection by the pathogenic bacterium Streptococcus mutans KCTC 5124 through biofilm formation inhibition. To evaluate such prevention effects against S. mutans KCTC 5124, antimicrobial activity, auto-aggregation, co-aggregation, cell surface hydrophobicity, total exopolysaccharide (EPS) production rate, and biofilm formation were analyzed. Results showed that L. plantarum Ln4 showed higher antimicrobial activity than L. rhamnosus GG (LGG). In the group treated with L. plantarum Ln4, the co-aggregation (58.85%), cell surface hydrophobicity (16.75%), and EPS production rate (73.29%) values were lower than those of LGG and the negative control. Additionally, crystal violet staining and confocal laser scanning microscopy (CLSM) revealed that L. plantarum Ln4 effectively inhibited biofilm formation in S. mutans KCTC 5124. Therefore, L. plantarum Ln4 could be used in the industry as a probiotics to prevent and improve oral health.

The role of Bifidobacterium genus in modulating the neonate microbiota: implications for antibiotic resistance acquisition in early life

Resistance to antibiotics in newborns is a huge concern as their immune system is still developing, and infections and resistance acquisition in early life have short- and long-term consequences for their health. Bifidobacterium species are important commensals capable of dominating the infant gut microbiome and are known to be less prone to possess antimicrobial resistance genes than other taxa that may colonize infants. We aimed to study the association between Bifidobacterium-dominated infant gut microbiota and the antibiotic resistant gene load in neonates, and to ascertain the perinatal factors that may contribute to the antibiotic resistance acquisition. Two hundred infant fecal samples at 7 days and 1 month of age from the MAMI birth cohort were included in the study and for whom maternal-neonatal clinical records were available. Microbiota profiling was carried out by 16S rRNA amplicon sequencing, and targeted antibiotic resistance genes (ARGs) including tetM, tetW, tetO, blaTEM, blaSHV and ermB were quantified by qPCR. Infant microbiota clustered into two distinct groups according to their Bifidobacterium genus abundance: high and low. The main separation of groups or clusters at each time point was performed with an unsupervised non-linear algorithm of k-means partitioning to cluster data by time points based on Bifidobacterium genus relative abundance. Microbiota composition differed significantly between both groups, and specific bifidobacterial species were enriched in each cluster. Lower abundance of Bifidobacterium in the infant gut was associated with a higher load of antibiotic resistance genes. Our results highlight the relevance of Bifidobacterium genus in the early acquisition and establishment of antibiotic resistance in the gut. Further studies are needed to develop strategies to promote a healthy early colonization and fight against the spread of antibiotic resistances.

Pathogenic Biofilm Removal Potential of Wild-Type Lacticaseibacillus rhamnosus Strains

The emergence of antimicrobial resistance remains one of the greatest public health concerns. Biofilm formation has been postulated as a mechanism of microbial pathogens to resist antimicrobial agents. Lactic Acid Bacteria (LAB) and their metabolites have been proposed to combat bacterial biofilms due to their antimicrobial activity. In this vein, the aim of the present study was to investigate the biofilm removal potential of cell-free supernatants (CFSs) of five wild-type Lacticaseibacillus rhamnosus strains, isolated from Greek natural products, in comparison to the commercially available L. rhamnosus GG strain, against biofilms formed by common foodborne pathogens (Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus). The biofilm removal activity of LAB was assessed on a two-day-old mature biofilm using a microtiter plate-based procedure. Both non-neutralized and neutralized CFSs removed biofilms in a concentration-dependent manner. The biofilm removal activity of the non-neutralized CFSs was significantly higher compared to the neutralized CFSs, as expected, with ranges of 60-89% and 30-80%, respectively. The biofilm removal efficiency of L. rhamnosus OLXAL-3 was significantly higher among the wild-type L. rhamnosus strains tested (20-100% v/v). In conclusion, our results suggest the great potential of the application of wild-type L. rhamnosus strain' CFSs as effective natural agents against pathogenic bacterial biofilms.

The urobiome in men and women: a clinical review

BACKGROUND

Antibiotic therapy alone is unable to control recurrent urinary tract infection (UTI); uropathogens have become multiresistant, and alternative strategies are needed. Far from sterile, the urinary tract contains various low-biomass microbiota, some of whose members appear to protect against clinical UTI.

OBJECTIVES

This narrative review summarizes (a) the current knowledge of male and female urobiomes in healthy and diseased states, as well as their interplay among sexual partners and (b) clinical trials to date assessing probiotic and other nonantibiotic measures to reduce UTI.

SOURCES

We used the PubMed interface to search Ovid Medline for articles describing urogenital flora, UTI, UTI dysbiosis, the effects of sexual intercourse on urogenital flora, and clinical trials of probiotics as UTI prophylaxis.

CONTENT

The healthy urobiome of women contains several Lactobacillus species, some of which may impede Escherichia coli growth in the urinary tract. Although Lactobacilli have been found in male urethral microbiota, their presence in male bladder microbiota is less certain. Distal male urethral and vaginal microbiomes of male and sexual female partners influence one another, but more research is needed on the direct interplay of their full urobiomes. Clinical trials assessing the therapeutic potential of Lactobacilli have been largely underpowered and highly varied in tested formulations and routes and frequencies of administration; as such, they have failed to show a clear benefit. Faecal microbiota transplantation for recurrent Clostridium difficile infection was shown, in a retrospective study of seven patients, to reduce recurrent UTI as a side effect.

IMPLICATIONS

The urobiome in men and women is complex, variable, and still understudied. Although there is hope that Lactobacilli and faecal microbial transplantation could be future nonantibiotic options for recurrent UTI, both require more pharmacologic and clinical research to identify optimal preparations and routes of administration.

Novel Dietary Approach with Probiotics, Prebiotics, and Synbiotics to Mitigate Antimicrobial Resistance and Subsequent Out Marketplace of Antimicrobial Agents: A Review

Antimicrobial resistance (AMR) is a significant public health concern worldwide. The continuous use and misuse of antimicrobial agents have led to the emergence and spread of resistant strains of bacteria, which can cause severe infections that are difficult to treat. One of the reasons for the constant development of new antimicrobial agents is the need to overcome the resistance that has developed against existing drugs. However, this approach is not sustainable in the long term, as bacteria can quickly develop resistance to new drugs as well. Additionally, the development of new drugs is costly and time-consuming, and there is no guarantee that new drugs will be effective or safe. An alternative approach to combat AMR is to focus on improving the body's natural defenses against infections by using probiotics, prebiotics, and synbiotics, which are helpful to restore and maintain a healthy balance of bacteria in the body. Probiotics are live microorganisms that can be consumed as food or supplements to promote gut health and improve the body's natural defenses against infections. Prebiotics are non-digestible fibers that stimulate the growth of beneficial bacteria in the gut, while synbiotics are a combination of probiotics and prebiotics that work together to improve gut health. By promoting a healthy balance of bacteria in the body, these can help to reduce the risk of infections and the need for antimicrobial agents. Additionally, these approaches are generally safe and well tolerated, and they do not contribute to the development of AMR. In conclusion, the continuous development of new antimicrobial agents is not a sustainable approach to combat AMR. Instead, alternative approaches such as probiotics, prebiotics, and synbiotics should be considered as they can help to promote a healthy balance of bacteria in the body and reduce the need for antibiotics.

Escherichia coli Nissle 1917 inhibits biofilm formation and mitigates virulence in Pseudomonas aeruginosa

In the quest for mitigators of bacterial virulence, cell-free supernatants (CFS) from 25 human commensal and associated bacteria were tested for activity against Pseudomonas aeruginosa. Among these, Escherichia coli Nissle 1917 CFS significantly inhibited biofilm formation and dispersed extant pseudomonas biofilms without inhibiting planktonic bacterial growth. eDNA was reduced in biofilms following exposure to E. coli Nissle CFS, as visualized by confocal microscopy. E. coli Nissle CFS also showed a significant protective effect in a Galleria mellonella-based larval virulence assay when administrated 24 h before challenge with the P. aeruginosa. No inhibitory effects against P. aeruginosa were observed for other tested E. coli strains. According to proteomic analysis, E. coli Nissle CFS downregulated the expression of several P. aeruginosa proteins involved in motility (Flagellar secretion chaperone FliSB, B-type flagellin fliC, Type IV pilus assembly ATPase PilB), and quorum sensing (acyl-homoserine lactone synthase lasI and HTH-type quorum-sensing regulator rhlR), which are associated with biofilm formation. Physicochemical characterization of the putative antibiofilm compound(s) indicates the involvement of heat-labile proteinaceous factors of greater than 30 kDa molecular size.

Bifidobacterium: Host-Microbiome Interaction and Mechanism of Action in Preventing Common Gut-Microbiota-Associated Complications in Preterm Infants: A Narrative Review

The development and health of infants are intertwined with the protective and regulatory functions of different microorganisms in the gut known as the gut microbiota. Preterm infants born with an imbalanced gut microbiota are at substantial risk of several diseases including inflammatory intestinal diseases, necrotizing enterocolitis, late-onset sepsis, neurodevelopmental disorders, and allergies which can potentially persist throughout adulthood. In this review, we have evaluated the role of Bifidobacterium as commonly used probiotics in the development of gut microbiota and prevention of common diseases in preterm infants which is not fully understood yet. The application of Bifidobacterium as a therapeutical approach in the re-programming of the gut microbiota in preterm infants, the mechanisms of host-microbiome interaction, and the mechanism of action of this bacterium have also been investigated, aiming to provide new insights and opportunities in microbiome-targeted interventions in personalized medicine.

Formulation of Cinnamon (Cinnamomum verum) oil loaded solid lipid nanoparticles and evaluation of its antibacterial activity against Multi-drug Resistant Escherichia coli

Today, the increment in microbial resistance has guided the researches focus into new antimicrobial compounds or transmission systems. Escherichia coli (E. coli) is an opportunistic pathogen, producing a biofilm responsible for a wide range of nosocomial infections which are often difficult to eradicate with available antibiotics. On the other hand, Cinnamomum verum (cinnamon oil) (CO) is widely used as a natural antibacterial agent and Solid lipid nanoparticles (SLNs) are promising carriers for antibacterial compounds due to their lipophilic nature and ease of transmission through the bacterial cell wall. In this study, nanoparticles containing cinnamon oil (CO-SLN) were prepared by dual emulsion method and evaluated in terms of particle size, shape, entrapment efficiency (EE), transmission electron microscopy (TEM), oil release kinetics, and cell compatibility. The antibacterial activity of CO-SLN and CO against 10 drug-resistant E. coli strains was investigated. The anti-biofilm activity of CO-SLN on the selected pathogen was also investigated. Nanoparticles with an average size of 337.6 nm, and zeta potential of -26.6 mV were fabricated and their round shape was confirmed by TEM images. The antibacterial effects of CO-SLN and CO were reported with MIC Value of 60–75 µg/mL and 155–165 µg/mL and MBC value of 220–235 µg/ml and 540–560 µg/ml, respectively. On the other hand, CO-SLN with 1/2 MIC concentration had the greatest inhibition of biofilm formation in 24 h of incubation (55.25%). The data presented indicate that the MIC of CO-SLN has significantly reduced and it seems that SLN has facilitated and promoted CO transmission through the cell membrane.

Exopolysaccharide of Enterococcus faecium L15 promotes the osteogenic differentiation of human dental pulp stem cells via p38 MAPK pathway

Background

Bone has important functions in the body. Several researchers have reported that the polysaccharides and lipopolysaccharide derived from microbes can promote osteogenic differentiation of stem cells. Enterococcus faecium, a lactic acid bacterium (LAB), produces several bioactive metabolites and has been widely applied in the food and nutraceutical industries. The exopolysaccharide (EPS) from LAB has also been extensively examined for its postbiotic effects and for its in vivo and in vitro functionalities. However, studies on promoting bone differentiation using polysaccharides from LAB are lacking. Therefore, the purpose of this study was to investigate the effect of E. faecium L15 extract and EPS on osteogenic differentiation of human dental pulp stem cells (hDPSCs) and to identify the underlying mechanisms.

Methods

hDPSCs were obtained from dental pulp tissue, and L15 extract and EPS were isolated from L15. Gene and protein expression of the osteogenic differentiation markers were analyzed with qPCR and western blotting and the possible signaling pathways were also investigated using western blotting. Osteogenic differentiation potential was examined by alkaline phosphatase (ALP) staining and alizarin red s (ARS) staining. In addition, osteogenic differentiation potential of L15 EPS was explored in ex vivo culture of neonate murine calvaria.

Results

The calcium deposition and ALP activity were enhanced by addition of L15 extract or EPS. The expression levels of RUNX2, ALP, and COL1A1 mRNA and the protein expression levels of RUNX2, ALP, and BMP4 were increased in hDPSCs treated with the L15 extract or EPS. The L15 EPS treatment enhanced phosphorylation of the p38 mitogen-activated protein kinase (MAPK). The L15 EPS-induced increases in RUNX2, ALP, and BMP4 expression were suppressed by the p38 MAPK inhibitor SB203580. The promoting effect of L15 EPS on osteogenic differentiation was not only seen in hDPSCs, but also in osteoblast precursors. ALP activity and the expression of RUNX2, ALP, and COL1A1 increased in the L15 EPS-treated osteoblast precursors. In addition, L15 EPS increased bone thickness of neonate murine calvaria in ex vivo culture.

Conclusions

The stimulatory effect of L15 extract and EPS on osteogenic differentiation occurred through the p38 MAPK pathway, and L15 EPS enhanced new bone formation in neonate murine calvaria. These data suggest that L15 EPS has therapeutic potential applicable to bone regeneration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03151-0.

Probiotics: Lactic Acid Bacteria have Antibacterial Activity and Downregulate Biofilm Genes of Uropathogenic E. coli

Urinary tract infections (UTIs) are regarded as one of the most serious infections worldwide. Uro Pathogenic E. coli (UPEC) accounts for nearly 80% of UTI infections in females. This study investigated the antibacterial and antibiofilm effects of Lactobacillus acidophilus (l. acidophilus) and Lactobacillus plantarum (lb. plantarum) on multidrug-resistant E. coli obtained from urine samples. Complete bacteriological identification was conducted on 45 E. coli isolated from 80 urine samples of females with UTIs. Antibiotic susceptibility test was performed on all isolates by nine antibiotics. Ten out of the 45 isolates exhibited multidrug resistance (MDR). L. acidophilus and Lb. plantarum showed marked inhibition of MDR E. coli isolates on agar by a diffusion method (16 ± 0.04: 23 ± 0.05 mm). Moreover, L. acidophilus and Lb. plantarum strains inhibited the ability of UPEC to form a biofilm by 56.3% and 39.63%, respectively. The expression of biofilm genes of E. coli are as follows: csgA, crl, csgD showed remarkable downregulation after treatment with probiotics suspension: 0.00364: 0.19078 fold, 0.0005: 0.1894 fold, and 0.0490: 0.0883 for L. acidophilus, respectively. On the other hand, downregulation of biofilm gene expression for csgA, crl, csgD after treatment with Lb. plantarum suspension were expressed by fold changes as follows: 0.0769: 0.3535 fold, 0.05440: 0.12940 fold, and 0.06745: 0.4146, respectively. These findings show that L. acidophilus and Lb. plantarum exhibit potent antibacterial and antibiofilm action against MDR UPEC at both genotypic and phenotypic levels, and appear to be a promising solution in therapeutic applications for recurrent and persistent UTIs.

In vitro and in vivo evaluation of Bacillus clausii against Schistosoma mansoni

Experimental studies and clinical trials have been showing that probiotics are promising in the prevention and control of parasite infections. B. clausii, obtained from Enterogermina®, was cultured to obtain cell-free culture supernatant (CFS) and spores to evaluate its schistosomicidal effect in vitro and in vivo against Schistosoma mansoni, respectively. For in vitro and in vivo analysis mice were infected with 120 and 50 cercariae, respectively. Couples of adult worms, recovered on day 45 of infection, were exposed to CFS. The in vivo assay was performed for 100 days, where all animals were infected on the 30^th day. Four experimental groups were formed, as follows: G1 - Saline solution from the 1^st until the 100^th day; G2 - B. clausii from the 1^st until the 100^th day; G3 - B. clausii from the 68^th day (onset of oviposition) until the 100^th day and G4 - PZQ (50 mg/Kg) from the 75^th until the 79^th day. In vitro, CFS of B. clausii does not caused mortality nor changed the motility on S. mansoni adult worms. G2 and G3 showed reduction of the 68.58 and 44.25% in the number of eggs eliminated in the feces and 34.29 and 53.6% and 22.8 and 48.49% the number of eggs trapped in the liver and intestine, respectively. Furthermore, in both therapeutic regimens G2 and G3, B. clausii increased the percentage of dead eggs in the intestinal tissue. B. clausii CFS, in vitro, does not showed action against S. mansoni and that treatment with B. clausii spores modulates favorably the parasitological parameters in the experimental infection of S. mansoni.

Characterization and potential oral probiotic properties of Lactobacillus plantarum FT 12 and Lactobacillus brevis FT 6 isolated from Malaysian fermented food

OBJECTIVE

This study aims to characterise the lactic acid bacteria (LAB) isolated from local Malaysian fermented foods with oral probiotics properties.

DESIGN

The LAB strains isolated from Malaysian fermented foods, Lactobacillus brevis FT 6 and Lactobacillus plantarum FT 12, were assessed for their antimicrobial properties against Porphyromonas gingivalis ATCC 33277 via disc diffusion assay. Anti-biofilm properties were determined by treating the overnight P. gingivalis ATCC 33277 biofilm with different concentrations of LAB cell-free supernatant (LAB CFS). Quantification of biofilm was carried out by measuring the optical density of stained biofilm. The ability of L. brevis FT 6 and L. plantarum FT 12 to tolerate salivary amylase was also investigated. Acid production with different sugars was carried out by pH measurement and screening for potential antimicrobial organic acid by disc diffusion assay of neutralised probiotics CFS samples. In this study, L. rhamnosus ATCC 7469, a commercial strain was used to compare the efficacy of the isolated strain with the commercial strain.

RESULTS

Lactobacillus brevis FT 6 and L. plantarum FT 12 possess antimicrobial activity against P. gingivalis with inhibition diameters of more than 10 mm, and the results were comparable with L. rhamnosus ATCC 7469. The MIC and MBC assay results for all tested strains were recorded to be 25 µl/µl concentration. All LAB CFS reduced biofilm formation proportionally to the CFS concentration and tolerated salivary amylase with more than 50% viability. Overnight cultures of all lactic acid bacteria strains showed a pH reduction and neutralised CFS of all lactic acid bacteria strains did not show any inhibition towards P. gingivalis.

CONCLUSIONS

These results indicate that the isolated probiotics have the potential as probiotics to be used as a supportive oral health treatment, especially against a periodontal pathogen, P. gingivalis.

Bacterial driver-passenger model in biofilms: a new mechanism in the development of colorectal cancer

Colorectal cancer (CRC) is a heterogeneous disease of the intestinal epithelium and ranks the third largest diagnosed malignancy in the world. Many studies have shown that the high risk of CRC is believed to be related to the formation of biofilms. To prove causation, it will be significant to decipher which specific bacteria in biofilms initiate and maintain CRC and fully describe their underlying mechanisms. Here we introduce a bacterial driver-passenger model. This model added a novel and compelling angle to the role of microorganisms, putting more emphasis on the transformation of bacterial composition in biofilms which play different roles in the development of CRC. In this model, bacterial drivers can initiate the formation of CRC through genotoxicity, while bacterial passengers maintain the CRC process through metabolites. On the basis of these pathogens, we further turned our attention to strategies that can inhibit and eradicate these pathogenic biofilms, with the aim of finding new ways to hinder colorectal carcinogenesis.

Combinations of Peptide-Protein Extracts from Native Probiotics Suppress the Growth of Multidrug-Resistant Staphylococcus aureus and Citrobacter freundii via Membrane Perturbation and Ultrastructural Changes

The occurrence of multidrug-resistant pathogens in the food chain causes health problems in humans, thus, research for novel antimicrobials to combat their growth is of interest. This study evaluates the antimicrobial potential of several combinations of peptide-protein extracts (PCs) consisting of peptide extracts from three native probiotic strains, Lactiplantibacillus plantarum UTNGt2, Lactococcus lactis UTNGt28, and L. plantarum UTNGt21A, alone or in combination with EDTA (ethylenediaminetetraacetic acid) against multidrug-resistant Staphylococcus aureus ATCC1026 and Citrobacter freundii UTNB3Sm1. Based on the antimicrobial assay, among the 19 tested PCs, two (PC11 and PC17) produced a greater zone of inhibition against both pathogens in vitro. Time-killing assays indicated the rapid death of S. aureus after exposure to PC11 and PC17, while C. freundii was rapidly inhibited by PC11 and PC1 (UTNGt2 only), suggesting that the inhibitory action is pathogen and dose-dependent of a particular molecule present in the extract. A marginal inhibitory effect was observed when the peptides were combined with EDTA. Transmission electron microscopy (TEM) revealed the structural membrane damage of both target strains upon interaction with individual peptide extracts. Different degrees of cell deformation, condensed cytoplasm, membrane blebbing, and ghost cell formation with visibly broken cell walls were observed in S. aureus. Likewise, the separation of the cytoplasmic membrane from the outer membrane, ghost cells, along with ovoid and deformed cells with undulated cell walls were observed for C. freundii. Furthermore, scanning electronic microscopy (SEM) analysis revealed different wrinkled and deformed cells covered by debris. A leakage of aromatic molecules was detected for both pathogens, indicating that PCs disrupted the cell wall integrity, inducing cell death. Given their inhibitory action and capacity to induce damage of the cytoplasmic membrane, the selected PCs may serve to slow bacterial growth in vitro; further research is required to prove their efficiency ex vitro to battle against food poisoning and subsequent human infection.

Modulation of Gut Microbiota and Immune System by Probiotics, Pre-biotics, and Post-biotics

The human gastrointestinal tract harbours a complex microbial community, which interacts with the mucosal immune system closely. Gut microbiota plays a significant role in maintaining host health, which could supply various nutrients, regulate energy balance, modulate the immune response, and defence against pathogens. Therefore, maintaining a favourable equilibrium of gut microbiota through modulating bacteria composition, diversity, and their activity is beneficial to host health. Several studies have shown that probiotics and pre-biotics could directly and indirectly regulate microbiota and immune response. In addition, post-biotics, such as the bioactive metabolites, produced by gut microbiota, and/or cell-wall components released by probiotics, also have been shown to inhibit pathogen growth, maintain microbiota balance, and regulate an immune response. This review summarises the studies concerning the impact of probiotics, pre-biotics, and post-biotics on gut microbiota and immune systems and also describes the underlying mechanisms of beneficial effects of these substances. Finally, the future and challenges of probiotics, pre-biotics, and post-biotics are proposed.

Recent Development of Probiotic Bifidobacteria for Treating Human Diseases

Bifidobacterium is a non-spore-forming, Gram-positive, anaerobic probiotic actinobacterium and commonly found in the gut of infants and the uterine region of pregnant mothers. Like all probiotics, Bifidobacteria confer health benefits on the host when administered in adequate amounts, showing multifaceted probiotic effects. Examples include B. bifidum, B. breve, and B. longum, common Bifidobacterium strains employed to prevent and treat gastrointestinal disorders, including intestinal infections and cancers. Herein, we review the latest development in probiotic Bifidobacteria research, including studies on the therapeutic impact of Bifidobacterial species on human health and recent efforts in engineering Bifidobacterium. This review article would provide readers with a wholesome understanding of Bifidobacteria and its potentials to improve human health.

Current Treatment Strategies Against Multidrug-Resistant Bacteria: A Review

There are several bacteria called superbugs that are resistant to multiple antibiotics which can be life threatening specially for critically ill and hospitalized patients. This article provides up-to-date treatment strategies employed against some major superbugs, like methicillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, vancomycin-resistant Enterococcus, multidrug-resistant Pseudomonas aeruginosa, and multidrug-resistant Escherichia coli. The pathogen-directed therapeutics decrease the toxicity of bacteria by altering their virulence factors by specific processes. On the other hand, the host-directed therapeutics limits these superbugs by modulating immune cells, enhancing host cell functions, and modifying disease pathology. Several new antibiotics against the global priority superbugs are coming to the market or are in the clinical development phase. Medicinal plants possessing potent secondary metabolites can play a key role in the treatment against these superbugs. Nanotechnology has also emerged as a promising option for combatting them. There is urgent need to continuously figure out the best possible treatment strategy against these superbugs as resistance can also be developed against the new and upcoming antibiotics in future. Rational use of antibiotics and maintenance of proper hygiene must be practiced among patients.

Biofilm formation and antagonistic activity of Lacticaseibacillus rhamnosus (PTCC1712) and Lactiplantibacillus plantarum (PTCC1745)

Currently, the health benefits of probiotic bacteria are well known, and this has taken up a great deal of space in food science and health, both research and operational. On the other hand, anti-biofilm properties on food pathogens in the food and pharmaceutical industries have created an attractive challenge. This study aimed to describe the inhibitory activity of cell-free supernatants (CFS), planktonic cells, and biofilm form of lactobacilus strains (L. rhamnosus and L. plantarum) against food pathogens such as Pseudomonas aeruginosa and Listeria monocytogenes. Anti-bacterial activities of the CFS of lactobacillus strains were assessed by the microplate method and via violet staining. Evaluation of the antagonistic activity of planktonic cells and biofilm of LAB were performed by the spread plate method. The results showed the incubation time of 48 h was the best time to produce biofilm. Although the planktonic states reduce the pathogens bacterial about 1 –1.5 log, but in biofilm forms, decreased L. monocytogenes about 4.5 log compared to the control, and in the case of P. aeruginosa, a growth reduction of about 2.13 log was observed. Furthermore, biofilm formation of L. monocytogenes in the presence of L. rhamnosus cell-free supernatant was more weakly than L. plantarum CFS, but their CFS effect on reducing the bacterial population of P. aeruginosa was the same. According to the study, biofilm produced by probiotic strains can be considered a new approach for biological control. Also, cell-free supernatant can be used as postbiotic in the food and pharmaceutical industries.

Lactobacillus plantarum in Dual-Species Biofilms With Listeria monocytogenes Enhanced the Anti-Listeria Activity of a Commercial Disinfectant Based on Hydrogen Peroxide and Peracetic Acid

The aim of this work was to investigate the effect of dual-species biofilms of Listeria monocytogenes with Lactobacillus plantarum on the anti-Listeria activity of a hydrogen peroxide/peracetic acid based commercial disinfectant (P3, Oxonia) when using conditions approaching the food industry environment. Nine strains of L. monocytogenes, including eight persistent strains collected from the meat industry and one laboratory control strain, were used in mono and in dual-species biofilms with a strain of L. plantarum. Biofilms were produced on stainless steel coupons (SSCs), at 11°C (low temperature) or at 25°C (control temperature), in TSB-YE (control rich medium) or in 1/10 diluted TSB-YE (mimicking the situation of biofilm formation after a deficient industrial cleaning procedure). The biofilm forming ability of the strains was evaluated by enumeration of viable cells, and the antibiofilm activity of P3 was assessed by the log reduction of viable cells on SSC. In both nutrient conditions and at low temperature, there was no significant difference (p > 0.05) between L. monocytogenes biofilm forming ability in mono- and in dual-species biofilms. In dual-species biofilms, L. monocytogenes was the dominant species. However, it was generally more susceptible to the lower concentration of P3 0.5% (v/v) than in pure culture biofilms. The presence of L. plantarum, although without significant interference in the number of viable cells of L. monocytogenes, enhanced the efficacy of the anti-Listeria activity of P3, since dual-species biofilms were easier to control. The results presented here reinforce the importance of the investigation into co-culture biofilms produced in food industry conditions, namely at low temperatures, when susceptibility to sanitizers is being assessed.

The beneficial effects of a multistrain potential probiotic, formic, and lactic acids with different vaccination regimens on broiler chickens challenged with multidrug-resistant Escherichia coli and Salmonella

The effects of a multistrain potential probiotic (Protexin®), acids, and a bacterin from multidrug-resistant E. coli O26, O78, S. Enteritidis (1,9,12 g.m1,7), and S. Typhimurium (1,4,5,12.i.1,2) on the immune response, haematological parameters, cytokines, and growth parameters of broiler chickens challenged with bacterin live serotypes were investigated. Two experiments were designed using 300 one-day-old chicks (Arbor Acres) randomly assigned to 15 groups. The first experiment comprised 9 groups, including positive and negative control groups and other groups received Protexin®, acids, and the bacterin (0.2 ml/SC), either alone or in combination, on the 1st day. The second experiment contained 6 groups, including positive and negative control groups and other groups received a combination of Protexin®, acids, and the bacterin (0.5 ml/SC) on the 8th day. All the groups except the negative control groups were challenged on the 8th and 16th days in both experiments, respectively, with mixed live bacterin serotypes. The groups that received Protexin®, acids, and the bacterin either alone or in combination revealed significant improvements in the immune response to the bacterin (p ≤ 0.05). The groups in the 1st experiment and most the 2nd experiment groups showed a reduced mortality rate and decreased levels IFN-γ, IL-4, and IL-12 cytokines (p ≤ 0.05). Moreover, these groups demonstrated increases in haematological parameters and reduced rates of infection-caused anaemia. These groups showed significant increases in growth performance parameters, such as body weight, weight gain, and the feed conversion ratio (FCR) (p ≤ 0.05). There was a beneficial effect on 1-day-old chickens produced by combining Protexin®, acids, and the bacterin (0.2 ml/SC).

Disinfectant resistance in bacteria: Mechanisms, spread, and resolution strategies

Disinfectants are widely acknowledged for removing microorganisms from the surface of the objects and transmission media. However, the emergence of disinfectant resistance has become a severe threat to the safety of life and health and the rational allocation of resources due to the reduced disinfectant effectiveness. The horizontal gene transfer (HGT) of disinfectant resistance genes has also expanded the resistant flora, making the situation worse. This review focused on the resistance mechanisms of disinfectant resistant bacteria on biofilms, cell membrane permeability, efflux pumps, degradable enzymes, and disinfectant targets. Efflux can be the fastest and most effective resistance mechanism for bacteria to respond to stress. The qac genes, located on some plasmids which can transmit resistance through conjugative transfer, are the most commonly reported in the study of disinfectant resistance genes. Whether the qac genes can be transferred through transformation or transduction is still unclear. Studying the factors affecting the resistance of bacteria to disinfectants can find breakthrough methods to more adequately deal with the problem of reduced disinfectant effectiveness. It has been confirmed that the interaction of probiotics and bacteria or the addition of 4-oxazolidinone can inhibit the formation of biofilms. Chemicals such as eugenol and indole derivatives can increase bacterial sensitivity by reducing the expression of efflux pumps. The role of these findings in anti-disinfectant resistance has proved invaluable.

Effects of therapeutic probiotics on modulation of microRNAs

Probiotics are beneficial bacteria that exist within the human gut, and which are also present in different food products and supplements. They have been investigated for some decades, due to their potential beneficial impact on human health. Probiotics compete with pathogenic microorganisms for adhesion sites within the gut, to antagonize them or to regulate the host immune response resulting in preventive and therapeutic effects. Therefore, dysbiosis, defined as an impairment in the gut microbiota, could play a role in various pathological conditions, such as lactose intolerance, gastrointestinal and urogenital infections, various cancers, cystic fibrosis, allergies, inflammatory bowel disease, and can also be caused by antibiotic side effects. MicroRNAs (miRNAs) are short non-coding RNAs that can regulate gene expression in a post-transcriptional manner. miRNAs are biochemical biomarkers that play an important role in almost all cellular signaling pathways in many healthy and disease states. For the first time, the present review summarizes current evidence suggesting that the beneficial properties of probiotics could be explained based on the pivotal role of miRNAs. Video Abstract.

Antimicrobial and Immunomodulatory Effects of Bifidobacterium Strains: A Review

Bifidobacterium strains can provide several health benefits, such as antimicrobial and immunomodulatory effects. Some strains inhibit growth or cell adhesion of pathogenic bacteria, including multidrug-resistant bacteria, and their antibacterial activity can be intensified when combined with certain antibiotics. In addition, some strains of bifidobacteria reduce viral infectivity, leading to less epithelial damage of intestinal tissue, lowering the virus shedding titer, and controlling the release of antiviral substances. Furthermore, bifidobacteria can modulate the immune system by increasing immunoglobulins, and inducing or reducing pro- or antiinflammatory cytokines, respectively. In particular, these anti-inflammatory effects are helpful in the treatment of patients who are already suffering from infection or inflammatory diseases. This review summarizes the antimicrobial effects and mechanisms, and immunomodulatory effects of Bifidobacterium strains, suggesting the potential of bifidobacteria as an alternative or complementary treatment option.

The effect of probiotics, parabiotics, synbiotics, fermented foods and other microbial forms on immunoglobulin production: a systematic review and meta-analysis of clinical trials

The aim of this systematic review and meta-analysis was to evaluate the effect of probiotics, parabiotics, synbiotics, fermented foods and other microbial forms on immunoglobulin production. We searched PubMed, Scopus, Web of Science, National Institute of Health Clinical Trials Register, and Cochrane Central Register of Clinical Trials, up to February 2020. All clinical trials that investigated the effects of oral intake of probiotics, parabiotics, synbiotics, fermented foods and other microbial forms on immunoglobulin (Ig)A, IgE, Japanese cedar pollen (JCP)-specific IgE, IgG, and IgM, for a duration of >7 days were included. Fifty-nine studies met the inclusion criteria, of these 54 studies were included in the analysis. The results indicated a significant increase in salivary IgA secretion rate (SMD = 0.21, 95% CI 0.02-0.39), while no significant effect was observed on other Igs. In conclusion, mentioned supplementation induced a small but significant effect on salivary secretion rate of IgA.

Antibacterial effects of antibiotics and cell-free preparations of probiotics against Staphylococcus aureus and Staphylococcus epidermidis associated with conjunctivitis

Conjunctivitis, caused by bacterial infections, represents health concern and diagnosis of the disease is pivotal for the proper selection of the treatment. The main causes of bacterial conjunctivitis vary in different countries. The current study investigated the common bacterial causes of bacterial conjunctivitis from eye clinics' attendants and evaluated the effectiveness of different therapeutic approaches. Eye swabs from patients, diagnosed with conjunctivitis, were assessed microbiologically and the isolated bacteria were identified using the standard biochemical identification and sequencing of the 16S rRNA gene. Antibiotics' susceptibility of the conjunctivitis-associated bacterial pathogens was evaluated against nineteen broad-spectrum antibiotics. In the meanwhile, cell-free preparations from probiotic Lactobacillus and Bifidobacterium strains were used to evaluate their antagonistic activities. Findings from this study showed that out of 52 specimen, 17 eye swabs from patients with conjunctivitis were bacterial culture-positive. The identity of the bacterial species, using the biochemical identification system, was Staphylococcus aureus (4 isolates) and S. epidermidis (13 isolates). Staphylococcus spp. showed susceptibility to linezolid, vancomycin, novobiocin, and fluoroquinolones (norfloxacin, ofloxacin, ciprofloxacin and levofloxacin). However, isolates from the two Staphylococcus spp. expressed resistance to penicillin G, oxacillin, and cephalexin. As alternatives to antibiotics, the growth of Staphylococcus spp., including isolates with antibiotic resistance, was inhibited by cell-free preparations of the 4 probiotic Lactobacillus and the 2 Bifidobacterium strains. These findings provide evidence that topical antibiotics such as fluoroquinolones are still effective antimicrobial agents against staphylococci associated with conjunctivitis whereas probiotic preparations could be promising for further research to pave the way for their therapeutic applications against ophthalmic diseases.

Selection of Potential Probiotic Bacteria from Exclusively Breastfed Infant Faeces with Antagonistic Activity Against Multidrug-Resistant ESKAPE Pathogens

The past decade has brought a significant rise in antimicrobial resistance, and the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) have considerably aggravated a threat to public health, causing nosocomial infections worldwide. The objective of the current study was to isolate novel probiotic strain with antimicrobial activity against multidrug-resistant ESKAPE pathogens. For this purpose, eighteen breastfed infant faeces were collected and lactic acid bacteria (LAB) with antagonistic activity were isolated. Out of 102 anaerobic LAB isolated, only nine exhibited inhibitory activity against all ESKAPE pathogens. These selected nine isolates were further characterized for their probiotic attributes such as lysozyme tolerance, simulated gastrointestinal tolerance, cellular auto-aggregation and cell surface hydrophobicity. Bile salt deconjugation and cholesterol-lowering capacity was also determined. Among all nine, isolate LBM220 was found to possess superior probiotic potential. Confirmatory identification of isolate LBM220 was done by both 16S rRNA sequence analysis and mass spectrometric analysis using MALDI-TOF. Based on BLAST result, isolate LBM220 was identified as Lactobacillus gasseri. Phylogenetic analysis of Lactobacillus gasseri LBM220 [accession number MN097539] was performed. Also, detailed safety evaluation study of Lact. gasseri LBM220 showed the presence of intrinsic antibiotic resistance and the absence of hemolytic, DNase, gelatinase and toxic mucinolytic activity. Time kill assay was also performed to confirm the strong kill effect of Lact. gasseri LBM220 on all six multidrug resistant ESKAPE pathogens. Thus, Lact. gasseri LBM220 can be utilized and explored as potential probiotic with therapeutic intervention.

Postbiotics against Pathogens Commonly Involved in Pediatric Infectious Diseases

The Sustainable Development goals for 2020 included reducing all causes associated with infant and perinatal mortality in their priorities. The use of compounds with bioactive properties has been proposed as a therapeutic strategy due to their stimulating effect on the host's immune system. Additionally, biotherapeutic products such as postbiotics, tentatively defined as compounds produced during a fermentation process that support health and well-being, promote intestinal barrier integrity without posing considerable risks to children's health. Although this is a concept in development, there are increasing studies in the field of nutrition, chemistry, and health that aim to understand how postbiotics can help prevent different types of infections in priority populations such as minors under the age of five. The present review aims to describe the main mechanisms of action of postbiotics. In addition, it presents the available current evidence regarding the effects of postbiotics against pathogens commonly involved in pediatric infections. Postbiotics may constitute a safe alternative capable of modulating the cellular response and stimulating the host's humoral response.

Current Antibiotic Resistance Trends of Uropathogens in Central Europe: Survey from a Tertiary Hospital Urology Department 2011-2019

Monitoring of pathogen resistance profiles is necessary to guide empirical antibiotic therapy before culture and sensitivity results become available. The aim of this study was to describe current antibiotic resistance patterns of five most frequent causative uropathogens in a Department of Urology of a tertiary referral centre in Central Europe over a period of nine years. The Hospital Department of Clinical Microbiology database was used to extract data on all positive urine samples from inpatients in the Department of Urology between 2011 and 2019. Numbers of susceptible and resistant isolates per year were calculated for five most frequent uropathogens: Escherichia coli, Enterococcus spp., Klebsiella spp., Pseudomonas aeruginosa, and Proteus spp. Antimicrobial agents selected for the survey included: ampicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam; cefuroxime, cefotaxime, ceftazidime and cefepime; ciprofloxacin and ofloxacin; gentamicin and amikacin; ertapenem, meropenem and imipenem; trimethoprim-sulfamethoxazole (co-trimoxazole), nitrofurantoin, colistin, and vancomycin. High resistance rates of Gram-negative uropathogens were demonstrated to most common antimicrobials, with statistically significant increasing or decreasing trends in some cases. No carbapenem-resistant Enterobacteriaceae were isolated. Vancomycin-resistant Enterococcus spp. strains were rare in our population.

Targeting Gut Microbial Biofilms-A Key to Hinder Colon Carcinogenesis?

Colorectal cancer (CRC) is a global public health issue which poses a substantial humanistic and economic burden on patients, healthcare systems and society. In recent years, intestinal dysbiosis has been suggested to be involved in the pathogenesis of CRC, with specific pathogens exhibiting oncogenic potentials such as Fusobacterium nucleatum, Escherichia coli and enterotoxigenic Bacteroides fragilis having been found to contribute to CRC development. More recently, it has been shown that initiation of CRC development by these microorganisms requires the formation of biofilms. Gut microbial biofilm forms in the inner colonic mucus layer and is composed of polymicrobial communities. Biofilm results in the redistribution of colonic epithelial cell E-cadherin, increases permeability of the gut and causes a loss of function of the intestinal barrier, all of which enhance intestinal dysbiosis. This literature review aims to compile the various strategies that target these pathogenic biofilms and could potentially play a role in the prevention of CRC. We explore the potential use of natural products, silver nanoparticles, upconverting nanoparticles, thiosalicylate complexes, anti-rheumatic agent (Auranofin), probiotics and quorum-sensing inhibitors as strategies to hinder colon carcinogenesis via targeting colon-associated biofilms.

Antibacterial effects of a polypeptide-enriched extract of Rana chensinensis via the regulation of energy metabolism

The improper usage of antibiotics is known to cause widespread antibiotic resistance. In this study, the antibacterial effects of a polypeptide-enriched extract from the skin of the amphibian Rana chensinensis (RCP) were evaluated against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive bacterium Staphylococcus aureus and the fungus Candida albicans. The mechanisms underlying these effects were also studied, and the minimum inhibitory concentration of RCP was determined for each species. Analyses of the levels of adenosine triphosphates (ATPases), including Na⁺/K⁺-ATPase and Ca²⁺-ATPase, and scanning electron microscopy confirmed that RCP damaged the microbial cell walls and membranes. RCP perturbed microbial metabolism and particularly affected the tricarboxylic acid cycle (TCA), suggesting that this agent downregulated the levels of succinate dehydrogenase, malate dehydrogenase and ATPase activity in cells. Furthermore, RCP caused the leakage of genetic material from all four microbial strains. In conclusion, RCP effectively inhibited the growth of Gram-negative and Gram-positive bacteria and a fungal species by disrupting energy metabolic processes.

Mechanistic insights into the action of probiotics against bacterial vaginosis and its mediated preterm birth: An overview

The human body is a reservoir of numerous micro-creatures; whose role is substantial and indispensable in the overall development of human beings. The advances in omic approaches have offered powerful means to decipher the core microbiome and metabolome diversities in a specific organ system. The establishment of lactobacilli in the female reproductive tract is thought to be a paramount prerequisite that maintains homeostatic conditions for a sustainable and healthy pregnancy. Nevertheless, a plethora of such Lactobacillus strains of vaginal source revealed probiotic phenotypes. The plummeting in the occurrence of lactobacilli in the vaginal ecosystem is associated with several adverse pregnancy outcomes (APOs). One such pathological condition is "Bacterial Vaginosis" (BV), a pathogen dominated gynecological threat. In this scenario, the ascending traffic of notorious Gram-negative/variable BV pathogens to the uterus is one of the proposed pathways that give rise to inflammation-related APOs like preterm birth. Since antibiotic resistance is aggravating among urogenital pathogens, the probiotics intervention remains one of the alternative biotherapeutic strategies to overcome BV and its associated APOs. Perhaps, the increased inclination towards the safer and natural biotherapeutic strategies rather than pharmaceutical drugs for maintaining gestational and reproductive health resulted in the use of probiotics in pregnancy diets. In this context, the current review is an attempt to highlight the microbiome and metabolites signatures of BV and non-BV vaginal ecosystem, inflammation or infection-related preterm birth, host-microbial interactions, role and effectiveness of probiotics to fight against aforesaid diseased conditions.

Evaluation of the Potential of Biofilm Formation of Bifidobacterium longum subsp. infantis and Lactobacillus reuteri as Competitive Biocontrol Agents Against Pathogenic and Food Spoilage Bacteria

This study proposes to exploit the in vivo metabolism of two probiotics (Bifidobacterium longum subsp. infantis and Lactobacillus reuteri) which, upon adhesion on a solid surface, form a biofilm able to control the growth of pathogenic and food spoilage bacteria. The results showed that pathogenic cell loads were always lower in presence of biofilm (6.5-7 log CFU/cm2) compared to those observed in its absence. For Escherichia coli O157:H7, a significant decrease (>1-2 logarithmic cycles) was recorded; for Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica, cell load reductions ranged from 0.5 to 1.5 logarithmic cycles. When tested as active packaging, the biofilm was successfully formed on polypropylene, polyvinyl chloride, greaseproof paper, polyethylene and ceramic; the sessile cellular load ranged from 5.77 log CFU/cm2 (grease-proof paper) to 6.94 log CFU/cm2 (polyethylene, PE). To test the potential for controlling the growth of spoilage microorganisms in food, soft cheeses were produced, inoculated with L. monocytogenes and Pseudomonas fluorescens, wrapped in PE pellicles with pre-formed biofim, packed both in air and under vacuum, and stored at 4 and 15 °C: an effective effect of biofilms in slowing the decay of the microbiological quality was recorded.

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.

Punica granatum sarcotesta lectin (PgTeL) has antibacterial activity and synergistic effects with antibiotics against β-lactamase-producing Escherichia coli

The sarcotesta of Punica granatum fruit contains an antimicrobial lectin called PgTeL. In this work, we evaluated the antibacterial activity of PgTeL against five drug-resistant Escherichia coli isolates able to produce β-lactamases. Minimum inhibitory (MIC) and bactericidal (MBC) concentrations were determined by broth dilution. Morphometric and viability analyses were performed by flow cytometry, and ultrastructural changes were evaluated by scanning electron microscopy. Potential synergistic effects of PgTeL with antibiotics and anti-biofilm effect were also evaluated. PgTeL showed antibacterial activity against all isolates with MIC and MBC values ranging from 12.5 to 50.0 μg/mL and from 25.0 to 100.0 μg/mL, respectively. For most isolates, PgTeL postponed the growth start by at least ten hours. At the MIC, the lectin caused alterations in size, shape and structure of bacterial cells. The combination PgTeL-ceftazidime showed a synergistic effect for all isolates. Synergy was also detected with ampicillin (one isolate), carbenicillin (one isolate), cefotaxime (one isolate), cephalexin (four isolates) and cefuroxime (three isolates). PgTeL exhibited anti-biofilm activity against all isolates, causing ≥50% inhibition of biofilms at or above 6.25 μg/mL. The antibacterial effect of PgTeL and its synergy with antibiotics indicate that this fruit-derived molecule may have potential for future treatment of multidrug-resistant infections.