Autochthonous cultures to improve the quality of PGI Castellano cheese: Impact on proteolysis, microstructure and texture during ripening.

The aim of this research was to find out the effect of different combinations of starter and non-starter cultures on the proteolysis of Castellano cheese during ripening. Four cheese batches were prepared, each containing autochthonous lactobacilli and or Leuconostoc, and were compared with each other and with a control batch, that used only a commercial starter. To achieve this, nitrogen fractions (pH 4.4-soluble nitrogen and 12 % trichloroacetic acid soluble nitrogen, polypeptide nitrogen and casein nitrogen), levels of free amino acids and biogenic amines were assessed. Texture and microstructure of cheeses were also evaluated. Significant differences in nitrogen fractions were observed between batches at different stages of ripening. The free amino acid content increased throughout the cheese ripening process, with a more significant increase occurring after the first 30 days. Cheeses containing non-starter lactic acid bacteria exhibited the highest values at the end of the ripening period. Among the main amino acids, GABA was particularly abundant, especially in three of the cheese batches at the end of ripening. The autochthonous lactic acid bacteria were previously selected as non-producers of biogenic amines and this resulted in the absence of these compounds in the cheeses. Analysis of the microstructure of the cheese reflected the impact of proteolysis. Additionally, the texture profile analysis demonstrated that the cheese's hardness intensified as the ripening period progressed. The inclusion of autochthonous non-starter lactic acid bacteria in Castellano cheese production accelerated the proteolysis process, increasing significantly the free amino acids levels and improving the sensory quality of the cheeses.

Bacteremia due to Leuconostoc species: A 13-year single-center case series.

INTRODUCTION: Leuconostoc spp. are facultatively anaerobic Gram-positive cocci involved in cases of hospital-acquired bacteremia, mainly in immunocompromised hosts. The available data is scarce due to its uncommon presentation. METHODS: We describe all the episodes of Leuconostoc spp. bacteremia in a third level hospital in a 13-year period (2008-2021). RESULTS: Four cases of clinically relevant bacteremia were detected. All cases were categorized as catheter-related. The following risk factors were found: previous glycopeptide therapy (75%), use of parenteral nutrition (100%) and cancer (75%). All isolates showed susceptibility to beta-lactams. Catheter removal was performed and wide spectrum antimicrobials were administered, with clinical response in all cases except one. DISCUSSION: Apart from cancer and glycopeptide exposure, disruption of skin barrier and gastrointestinal conditions were identified as risk factors, as it was concordantly underlined in other case series. Susceptibility to beta-lactams is usually maintained. Catheter removal and administration of an active antibacterial therapy seem to be the best approach for Leuconostoc spp. catheter-related bacteremia.

WAS IT LEUCONOSTOC SPECIES? A CASE OF DELAYED-ONSET ENDOPHTHALMITIS PRESENTING 14 YEARS AFTER CATARACT SURGERY.

PURPOSE: To report a case of delayed-onset endophthalmitis presenting 14 years after an uncomplicated cataract surgery. METHODS: Case report. RESULTS: An 89-year-old pseudophakic man complained of redness and reduced visual acuity in his right eye. He had no history of trauma or systemic infection, and his only surgery on the right eye was an uncomplicated cataract surgery 14 years before. On physical examination, he was found to have keratic precipitates and a white posterior capsular plaque in the right eye. He was treated with a right pars plana vitrectomy and intraocular lens removal. Microbiological classification of the samples revealed the presence of a Leuconostoc species within the vitreous humor and coagulase-negative staphylococci on the lens. Two months after placement of the intraocular lens, he achieved a best-corrected visual acuity of 20/200 in his right eye. CONCLUSION: To the best of our knowledge, this is the first reported case of delayed-onset endophthalmitis occurring more than 10 years after an uncomplicated cataract surgery. This case highlights a highly unusual presentation of delayed-onset endophthalmitis and reports a potential novel microbiological cause of plaque formation.

Engineering of Leuconostoc citreum for Efficient Bioconversion of Soy Isoflavone Glycosides to Their Aglycone Forms.

Soy isoflavones are phytochemicals that possess various beneficial physiological properties such as anti-aging, anti-tumor, and antioxidant properties. Since soy isoflavones exist in glycoside forms, their bioavailability requires initial hydrolysis of the sugar moieties bound to them to be efficiently absorbed through the gut epithelium. Instead of conventional chemical hydrolysis using acids or organic solvents, alternative strategies for enhancing the bioavailability of soy isoflavones using biological methods are gaining attention. Here, we engineered Leuconostoc citreum isolated from Korean kimchi for efficient bioconversion of soy isoflavone glycosides into their aglycone forms to enhance their bioavailability. We first constructed an expression module based on the isoflavone hydrolase (IH)-encoding gene of Bifidobacterium lactis, which mediates conversion of isoflavone glycosides to aglycone forms. Using a high copy number plasmid and bicistronic expression design, the IH was successfully synthesized in L. citreum. Additionally, we determined enzymatic activity of the IH using an in vivo ß-glucosidase assay and confirmed its highly efficient bioconversion efficiency for various types of isoflavone glycosides. Finally, we successfully demonstrated that the engineered L. citreum could convert isoflavone glycosides present in fermented soymilk into aglycones.

Leuconostoc, a masquerading pathogen in oral cancer patient: A rare case report.

Osteoradionecrosis is the most common cause of mandibular osteomyelitis. Here we are reporting a case of osteomyelitis of the mandible caused by Leuconostoc mesenteroides spp cremoris. The frequency of Leuconostoc infections are under reported mainly due to its difficult identification. Non pathogenic organism like leuconostoc can cause infection in the immunocompromised and should warrant proper microbial identification and adequate targeted treatment to manage the patients.

Postbiotic metabolites, antioxidant and anticancer activities of probiotic Leuconostoc pseudomesenteroides strains in natural pickles.

In this study, five strains of Leuconostoc pseudomesenteroides were thought to have probiotic properties and anticancer activity isolated from natural pickles and identified by performing the 16S rRNA sequence analysis. The probiotic properties, postbiotic amounts, the capacity to adhere to the L-929, HT-29 and Caco-2 cell lines, the effects of postbiotic and bacterial extracts on cell viability and biochemical activities were investigated in the strains. In the results, Leu. pseudomesenteroides Y6 strain was detected to have the best resistance to the stomach and intestinal environments, and the quantities of postbiotic metabolites are similar to each other. The bacterial adhesion capacities were found to be in the range of 1.66-8.5%. Furthermore, postbiotic metabolites of all isolates had good anticancer activity (27.67-86.05%) and the activity of bacterial extractions increased depending on concentration. Leu. pseudomesenteroides Y4 and Y6 strains generally showed better activity than controls and all strains were strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavengers in the antioxidant studies. In conclusion, the Y6 strain, which had the best probiotic feature, was found to show significantly good biological activity. It is thought that this isolate will be supported by new in vivo studies and eventually be brought to the food and health industry.

Biochemical characterization of synthesized fisetin glucoside by dextransucrase from Leuconostoc mesenteroides NRRL B-1299CB4 with enhanced water solubility.

Fisetin (7,3',4'-flavon-3-ol) is a flavonol found in plants, fruits, and vegetables. It exhibits diverse biological activities, including antioxidant, anti-inflammatory, and anti-cancer effects. However, the low water solubility and bioavailability of fisetin restrict its pharmaceutical applications. In this work, we synthesized a novel fisetin-4'-O-α-D-glucopyranoside (FST-G1) using transglucosylation with sucrose, fisetin, and dextransucrase from Leuconostoc mesenteroides NRRL B-1299CB4. The water solubility of FST-G1 (109.8 ± 6.3 mg/L) was enhanced compared to fisetin (13.6 ± 1.3 mg/L). The antioxidant activities of FST-G1 in non-cellular assays, including ORAC, ABTS•+, and FRAP assays, were lower compared to fisetin. However, FST-G1 exhibited higher nitric oxide inhibition (62.5 µM; 92.3 %) in lipopolysaccharide-stimulated RAW 264.7 murine macrophage cells compared to fisetin (81.4 %). Anti-lipid accumulation in mouse 3T3-L1 cells treated with FST-G1 was similar to that in cells treated with fisetin. Taken together, the novel synthesized FST-G1 is expected to become a promising functional material for using in the pharmaceutical industry.

Chemical Synthesis and Evaluation of Exopolysaccharide Fragments Produced by Leuconostoc mesenteroides Strain NTM048.

Exopolysaccharides (EPSs) occur widely in natural products made by bacteria, fungi and algae. Some EPSs have intriguing biological properties such as anticancer and immunomodulatory activities. Our group has recently found that EPSs generated from Leuconostoc mesenteroides ssp. mesenteroides strain NTM048 (NTM048 EPS) enhanced a production of mucosal immunoglobulin A (IgA) of mouse. Herein, we described the synthesis and evaluation of the tetrasaccharide fragments of NTM048 EPS to obtain information about the molecular mechanism responsible for the IgA-inducing activity.

Long-term drench of exopolysaccharide from Leuconostoc pseudomesenteroides XG5 protects against type 1 diabetes of NOD mice via stimulating GLP-1 secretion.

BACKGROUND: Type 1 diabetes is an autoimmune disease that results in the specific destruction of insulin-producing beta cells in the pancreas. The aim of this study was to investigate the mechanism of exopolysaccharide from Leuconostoc pseudomesenteroides XG5 (XG5 EPS) against type 1 diabetes. RESULTS: Long-term drench of XG5 EPS delayed the onset of autoimmune diabetes and had fewer islets with high-grade infiltration (an insulitis score of 3 or 4) than untreated NOD mice. Oral administration of 50 mg kg-1  d-1 XG5 EPS increased the insulin and glucagon-like peptide-1 (GLP-1) levels of serum, stimulated GLP-1 secretion and upregulated gcg mRNA expression of colon in NOD mice. Moreover, oral administration of 50 mg kg-1  d-1 XG5 EPS significantly increased total short-chain fatty acids levels in the colon contents, especially those of acetic acid and butyric acid. In NCI-H716 cells, 500 and 1000 µmol L-1 sodium butyrate promoted the secretion of GLP-1 and upregulated the mRNA expression of gcg and PC3, while XG5 EPS and sodium acetate did not stimulate the GLP-1 secretion. Therefore, long-term drench of XG5 EPS delayed the onset of autoimmune diabetes, which may be directly correlated with the increase of butyrate in the colon of NOD mice. CONCLUSION: Long-term drench of 50 mg kg-1  d-1 XG5 EPS promoted the expression and secretion of GLP-1 by increasing the production of butyric acid, thereby delaying T1D onset in NOD mice. © 2021 Society of Chemical Industry.

Rejection of the reclassification of Leuconostoc gasicomitatum as Leuconostoc gelidum subsp. gasicomitatum based on whole genome analysis.

In 2014, Rahkila et al. transferred Leuconostoc gasicomitatum to Leuconostoc gelidum as L. gelidum subsp. gasicomitatum comb. nov. based on a 75 % DNA-DNA hybridization value. In the present study, the taxonomic status of L. gelidum subsp. gasicomitatum is re-evaluated by a polyphasic approach, including 16S rRNA, pheS, rpoA, recA, and atpA gene sequence analyses, phylogenomic treeing, analyses of ANI (average nucleotide identity) and dDDH (digital DNA-DNA hybridization), fatty acid methyl ester analysis and a phenotypic characterization. On the basis of the ANI and dDDH values, we propose to reject the proposal of Rahkila et al. to reclassify L. gasicomitatum as L. gelidum subsp. gasicomitatum.

Isolation and Identification of Lactic Acid Bacteria from Cow Milk and Milk Products.

Lactic acid bacteria (LAB) have long been consumed by people in several fermented foods such as dairy products. A study was conducted on lactating dairy cows to isolate and characterize LAB from dairy products found in and around Bahir-Dar city, North Western Ethiopia. Milk and milk products were randomly collected from dairy farms, milk vending shops, individual households, and supermarkets for bacteriological investigations. A total of sixteen samples were taken from different sources and cultured on different selective media: de Man, Rogosa, and Sharpe (MRS) agar for Lactobacillus spp.; M17 agar for Lactococcus spp.; Rogasa SL agar for Streptococci spp.; and MRS supplemented with cysteine (0.5%) for Bifidobacteria spp. Different laboratory techniques were implemented for LAB isolation and identification. A total of 41 bacterial isolates were grouped under five different genera of LAB and Bifidobacteria spp. were identified based on the growth morphology on the selective media, growth at a different temperature, gas production from glucose, carbohydrate fermentation, and other biochemical tests. LAB genera such as Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, Streptococcus, and Bifidobacterium spp. were isolated and identified from raw milk, cheese, and yogurt. Based on the current study, the majority of the LAB (24.38%) was isolated from cheese and yogurt. Among these, Lactobacillus, Lactococcus (21.94%), Streptococcus (19.51%), Leuconostoc (14.64%), Bifidobacteria (12.19%), and Pediococcus (7.31%) spp. were also identified from these products. Furthermore, based on the bacterial load count and different identification methodologies, our study revealed that Lactobacillus spp. were the dominant LAB isolated from milk and milk products. As a result, since there are few studies on the isolation and identification of lactic acid bacteria from dairy products in Ethiopia, more research studies are needed to complete the identification and characterization to species level and their possible role as probiotics.

Characterization and Antioxidant Activity of Released Exopolysaccharide from Potential Probiotic Leuconostoc mesenteroides LM187.

A released exopolysaccharide (rEPS)-producing strain (LM187) with good acid resistance, bile salt resistance, and cholesterol-lowering properties was isolated from Sichuan paocai and identified as Leuconostoc mesenteroides subsp. mesenteroides. The purified rEPS, designated as rEPS414, had a uniform molecular weight of 7.757 × 105 Da. Analysis of the monosaccharide composition revealed that the molecule was mainly composed of glucose. The Fourier transform-infrared spectrum showed that rEPS414 contained both α-type and ß-type glycosidic bonds. 1H and 13C nuclear magnetic resonance spectra analysis showed that the purified rEPS contained arabinose, galactose, and rhamnose, but less uronic acid. Scanning electron microscopy demonstrated that the exopolysaccharide displayed a large number of scattered, fluffy, porous cellular network flake structures. In addition, rEPS414 exhibited strong in vitro antioxidant activity. These results showed that strain LM187 and its rEPS are promising probiotics with broad prospects in industry.

Infección de un muñón por Leuconostoc spp, reporte de un caso y revisión de la literatura / Infection of a stump by Leuconostoc, a case report and review of the literature

Resumen La infección del muñón después de amputaciones traumáticas tiene una prevalencia hasta del 34%. Las bacterias más frecuentemente aisladas son Staphylococcus aureus, Enterobacterales como Escherichia coli; Pseudomonas aeruginosa, entre otras. Estas infecciones ocurren por la inoculación directa en el momento del trauma o por gérmenes nosocomiales; la realización de curaciones de las heridas con emplastos vegetales es una práctica aún frecuente en zonas rurales de nuestro país pero su relación con infección del sitio operatorio ha sido poco explorada en la literatura. Leuconostoc spp. es un coco Gram positivo encontrado en territorio agrícola y utilizado en la industria de alimentos. Se presenta un caso de infección de un muñón transfemoral por Leuconostoc, después de una amputación traumática del miembro inferior en una paciente previamente sana con una posible asociación a curaciones con emplastos vegetales.

Abstract Infection of a traumatic amputation stump has a prevalence of 34%. The most common bacteria isolated are Staphylococcus aureus, Pseudomonas aeruginosa and Enterobacterales such as Escherichia coli. These infections occur by direct inoculation in the moment of the trauma or by nosocomial germs. Infections secondary to manipulation of the wounds with vegetable plasters have few case reports in the literature. Leuconostoc spp. is a Gram-positive coccobacillus commonly found in agricultural territory and used in the food industry. There are few case reports in the literature about bone infections by Leuconostocs pp. We present a case of an infection of the operative site of a transfemoral stump by Leuconostoc spp. after a traumatic amputation of the lower limb in a previously healthy patient who had a possible association to cures with vegetable plasters.

Leuconostoc falkenbergense sp. nov., isolated from a lactic culture, fermentating string beans and traditional yogurt.

In the present study, the taxonomic positions of five strains (C, 17-2, LMG 10779T, LMG 18969 and LMG 11483) of Leuconostoc pseudomesenteroides were re-evaluated by a polyphasic approach, including the analyses of 16S rRNA, pheS and rpoA gene sequences, cellular fatty acids, average nucleotide and amino acid identities (ANI and AAI), digital DNA-DNA hybridization (dDDH), and phenotypic features. Based on rpoA sequence analysis, the five strains and L. pseudomesenteroides LMG 11482T were divided into two groups: strains C, LMG 10779T and LMG 18969; strains 17-2, LMG 11483 and LMG 11482T. Each of the two groups had almost identical rpoA sequences. The rpoA sequence similarity between strain LMG 10779T and L. pseudomesenteroides LMG 11482T was 95.6 %. Strains LMG 11483 and 17-2 had 98.1 and 97.2 % ANI values, 83.5 and 73.2 % dDDH values, and a 97.0 % AAI value with L. pseudomesenteroides LMG 11482T, greater than the threshold for species demarcation, indicating that strains LMG 11483 and 17-2 belong to L. pseudomesenteroides. Strains LMG 18969 and C shared 97.1 and 98.2 % ANI values, 73.4 and 83.2 % dDDH values, and 96.9 and 96.6 % AAI values with strain LMG 10779T, greater than the threshold for species demarcation, indicating that strains LMG 10779T, LMG 18969 and C represent the same species. The ANI, dDDH and AAI values between strain LMG 10779T and the type strains of phylogenetically related species were 75.2-92.5, 20.0-48.2 and 75.3-93.9 %, respectively, below the thresholds for species demarcation, indicating that strain LMG 10779T represents a novel species within the genus Leuconostoc. On the basis of the results presented here, (i) strains 17-2 and LMG 11483 belong to L. pseudomesenteroides, and (ii) strains LMG 10779T, LMG 18969 and C are considered to represent a novel species within the genus Leuconostoc, for which the name Leuconostoc falkenbergense sp. nov. is proposed with the type strain LMG 10779T (=CCUG 27119T).

Leuconostoc lactis- A Rare Cause of Bacterial Meningitis in an Immunocompromised Host.

Leuconostoc lactis, often found in fermented dairy products, although considered to have a low pathogenic potential, can cause life-threatening infections in immunocompromised hosts. We herein report a 62-year-old man with a history of alcoholic liver cirrhosis, hepatocellular carcinoma, and diabetes mellitus who developed a very rare case of bacterial meningitis caused by this organism. After we administered antibiotics including ampicillin, he recovered completely within two weeks. This gram-positive coccus (GPC) is sensitive to ampicillin but naturally resistant to vancomycin, while its susceptibility to ceftriaxone has not yet been established. In acute GPC meningitis in immunocompromised hosts, Leuconostoc lactis should therefore be considered as a possible pathogen.

Synergistic antimicrobial activity of oregano and thyme thymol essential oils against Leuconostoc citreum in a laboratory medium and tomato juice.

This study was done to identify combinations of essential oils (EOs) that elicit synergistic antimicrobial effects against Leuconostoc citreum, a spoilage bacterium in vegetable and fruit juices. Twenty-four EOs were tested for antimicrobial activity against L. citreum using an agar well diffusion assay. Ten EOs showed relatively strong antimicrobial activity. Among those, cinnamon bark, oregano, and thyme thymol EOs showed the strongest activity (minimal inhibitory concentration = 1.25 µL/mL). It was confirmed that a combination of oregano and thyme thymol EOs had a synergistic antimicrobial activity (fractional inhibitory concentration index = 0.3750) using a checkerboard assay. This combination also had a synergistic antimicrobial activity against L. citreum in tomato juice. An initial population of L. citreum in tomato juice (5.3 log CFU/mL) increased to ≥ 8.6 log CFU/mL within 48 h at 15 °C and 24 h at 25 °C. Populations reached 6.8-7.2 log CFU/mL in tomato juice containing either 0.156 mL/mL oregano or thyme thymol. However, in the presence of both EOs (0.156 µL/mL in total), populations of L. citreum were significantly lower (5.7-6.5 log CFU/mL) (P ≤ 0.05). Findings will be useful when developing non-thermal food preservation technologies to increase the shelf-life of juices and other foods not containing synthetic preservatives.

Leuconostoc mesenteroides subsp. mesenteroides SD23 Prevents Metabolic Dysfunction Associated with High-Fat Diet-Induced Obesity in Male Mice.

High-fat diet (HFD) consumption induces obesity and increases blood glucose, insulin resistance, and metabolic disorders. Recent studies suggest that probiotics might be a novel approach to counteract these effects in the treatment of obesity. Here, we evaluated the effect of Leuconostoc mesenteroides subsp. mesenteroides SD23 on obesity-related metabolic dysfunction. In the present study, mice were randomly divided into four dietary groups: standard diet (C), HFD (OB), standard diet with L. mesenteroides SD23 (CP), and HFD with L. mesenteroides SD23 (OBP). Diets were maintained for 14 weeks. Animal weight was monitored and biochemical and histological analyses were performed after intervention. OB showed metabolic dysfunction, and increased the number of larger adipocytes compared to C. OB induced liver tumor necrosis factor-α (TNF-α) expression, increased cholesterol, leptin, and glucose levels compared to C. OBP reduced body weight, glucose, cholesterol, and leptin levels and improved glucose tolerance compared to OB. OBP also reduced liver steatosis, the number of larger adipocytes in adipose tissue, and reduced the villus height in the small intestine. OBP decreased expression of TNF-α and increased expression of IL-10 in liver. The parameters evaluated in the CP were similar to the C. This study provides novel evidence that dietary intervention with L. mesenteroides SD23 improves metabolic dysfunction related to obesity in HFD-fed mice.

Amelioration of colitis in mice by Leuconostoc lactis EJ-1 by M1 to M2 macrophage polarization.

Dysregulation of immune responses to environmental antigens by the intestine leads to the chronic inflammatory disease, inflammatory bowel disease (IBD). Recent studies have thus sought to identify a dietary component that can inhibit lipopolysaccharide (LPS)-induced nuclear factor-kappa beta (NF-κB) signaling to ameliorate IBD. This study assessed if the lactic acid bacteria (LAB) from kimchi, suppresses the expression of tumor necrosis factor-alpha (TNF-α) in peritoneal macrophages induced by LPS. Leuconostoc lactis EJ-1, an isolate from LAB, reduced the expression of interleukin-6 (IL-6) and IL-1ß in peritoneal macrophages induced by LPS. The study further tested whether EJ-1 alleviates colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice. TNBS significantly increased myeloperoxidase (MPO) expression, macroscopic colitis scores, and colon shortening. Oral administration of L. lactis EJ-1 resulted in an inhibited in TNBS-induced loss in body weight, colon shortening, MPO activity, and NF-κB and inducible nitric oxide synthase expression; it also led to a marked reduction in cyclooxygenase-2 expression. L. lactis EJ-1 also inhibited the TNBS-induced expression of TNF-α, IL-1ß, and IL-6; however, it induced the expression of IL-10. The M2 macrophage markers arginase I, IL-10, and CD206 were elevated by EJ-1. Collectively, these results suggest that EJ-1 inhibits the NF-κB signaling and polarizes M1- to M2-macrophage transition, which help in ameliorating colitis.

In Vivo and In Vitro Study of Immunostimulation by Leuconostoc lactis-Produced Gluco-Oligosaccharides.

Glycosyltransferase-producing Leuconostoc lactis CCK940 produces CCK- oligosaccharides, gluco-oligosaccharide molecules, using sucrose and maltose as donor and acceptor molecules, respectively. In this study, the immunostimulatory activities of CCK-oligosaccharides on RAW264.7 macrophages and BALB/c mice were evaluated. CCK-oligosaccharides induced the expression of phosphorylated-p38, extracellular-signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) and upregulation of phagocytic activity in RAW264.7 macrophages, suggesting their involvement in mitogen-activated protein kinase (MAPK) signaling pathway and phagocytosis. When CCK-oligosaccharides were administered to mice intraperitoneally injected with cyclophosphamide (CY), spleen indices and expressions of interleukin (IL)-6, IL-10, and tumor necrosis factor-α increased, compared with those in only CY-treated group. These findings suggest that CCK-oligosaccharides can be used as an effective immunostimulating agent.

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.