Aims: This study aimed to isolate and characterize putative new probiotic with antimicrobial properties against common fish pathogens from the gut of Oreochromis spp. (red tilapia). Methodology and results: A total of 28 colonies were isolated from gut of Oreochromis spp. and characterized phenotypically. Eight isolates were selected for probiotic characterization. Temperature, salinity, pH and bile salt tolerance, antibiotic susceptibility and antimicrobial test against selected fish pathogens (Aeromonas hydrophila, Edwardsiella tarda and Staphylococcus aureus subsp. aureus ATCC 25923) were conducted. Characterization studies revealed isolates suited for freshwater environment and exhibited tolerance against wide range of salinity, pH and bile salt. Isolates displayed different antibiotic susceptibility profile, with six exhibited antimicrobial properties against E. tarda. Molecular identification based on 16S rRNA gene sequencing showed 99.44%, 98.59% and 91.21% sequence similarity with Leuconostoc pseudomesenteroides strain 3832T, Leuconostoc lactis strain KCC202369T and Leuconostoc mesenteroides strain 4332T, respectively as compared to known sequence in the GenBank. When identified Leuconostoc spp. were coated on feed pellets, no major decrease in viability over 21 days of storage at 4 °C were observed, with an average of 8 log CFU/mL. Conclusion, significance and impact of study The characterized species allow further application assessment of the probiotic-supplemented tilapia feed. Host-originated Leuconostoc displayed potential antimicrobial properties against fish pathogen E. tarda. The isolates Leuconostoc is expected to provide protective effect for Oreochromis spp. against edwardsiellosis and to exert beneficial effects more efficiently as compared to commercial probiotics which are not specifically target for Oreochromis spp., thereby indirectly helping fish farmers in achieving economic sustainability and increase affordability of fish.
Leuconostoc ; Anti-Infective Agents ; Tilapia ; Edwardsiella tarda--pathogenicity ; Probiotics

Alopecia ; Classification ; Diarrhea ; Female ; Functional Food ; Hair ; Hair Follicle ; Humans ; Leuconostoc ; Male ; Pilot Projects ; Probiotics ; Scalp ; Soybeans

The objective of this study was to develop fermented vegetable juices that possess antidiabetic and antioxidant activities. Lactobacillus plantarum MKHA15 (MKHA15) and Leuconostoc mesenteroides MKSR (MKSR) were applied to ferment onion, cabbage, and tomato juices at 37℃ and 30℃ for 72 h, respectively, and their functionality was tested using the 12 h hour-fermented juice by MKHA15, and 48 h hour-fermented juice by MKSR. Inhibition of α-glucosidase activity was observed in all fermented juices. The onion juice fermented by MKHA15 showed significantly higher α-glucosidase inhibition activity compared to other juices. All juices showed more than 70% inhibition of α-amylase activity. The DPPH radical scavenging activity of onion juice fermented by MKSR showed significantly lower activity than cabbage and tomato juices; however, no difference was observed between the types of starter cultures. The SOD-like activity of cabbage juice fermented by MKSR was the highest among the fermented juices. The juices fermented by MKHA15 showed higher reducing power than those by MKSR. Therefore, we believe that cabbage, onion and tomato juice fermented by MKHA15 and MKSR would be useful in probiotic juices, as they possess antidiabetic and antioxidant activities.
Brassica ; Fruit and Vegetable Juices ; Lactobacillus plantarum ; Lactobacillus ; Leuconostoc ; Lycopersicon esculentum ; Onions ; Probiotics ; Vegetables

PURPOSE: The microbial environment is an important factor that contributes to the pathogenesis of atopic dermatitis (AD). Recently, it was revealed that not only bacteria itself but also extracellular vesicles (EVs) secreted from bacteria affect the allergic inflammation process. However, almost all research carried out so far was related to local microorganisms, not the systemic microbial distribution. We aimed to compare the bacterial EV composition between AD patients and healthy subjects and to experimentally find out the beneficial effect of some bacterial EV composition METHODS: Twenty-seven AD patients and 6 healthy control subjects were enrolled. After urine and serum were obtained, EVs were prepared from samples. Metagenomic analysis of 16s ribosomal DNA extracted from the EVs was performed, and bacteria showing the greatest difference between controls and patients were identified. In vitro and in vivo therapeutic effects of significant bacterial EV were evaluated with keratinocytes and with Staphylococcus aureus-induced mouse AD models, respectively. RESULTS: The proportions of Lactococcus, Leuconostoc and Lactobacillus EVs were significantly higher and those of Alicyclobacillus and Propionibacterium were lower in the control group than in the AD patient group. Therefore, lactic acid bacteria were considered to be important ones that contribute to the difference between the patient and control groups. In vitro, interleukin (IL)-6 from keratinocytes and macrophages decreased and cell viability was restored with Lactobacillus plantarum-derived EV treatment prior to S. aureus EV treatment. In S. aureus-induced mouse AD models, L. plantarum-derived EV administration reduced epidermal thickening and the IL-4 level. CONCLUSIONS: We suggested the protective role of lactic acid bacteria in AD based on metagenomic analysis. Experimental findings further suggest that L. plantarum-derived EV could help prevent skin inflammation.
Alicyclobacillus ; Animals ; Bacteria ; Cell Survival ; Dermatitis, Atopic* ; DNA, Ribosomal ; Extracellular Vesicles* ; Healthy Volunteers ; Humans ; In Vitro Techniques ; Inflammation ; Interleukin-4 ; Interleukins ; Keratinocytes ; Lactic Acid ; Lactobacillus* ; Lactococcus ; Leuconostoc ; Macrophages ; Metagenomics ; Mice ; Microbiota ; Probiotics ; Propionibacterium ; Skin ; Staphylococcus* ; Therapeutic Uses

Leuconostoc species are Gram-positive coccobacilli and are used in dairy products and are intrinsically resistant to vancomycin. Leuconostoc infections are rare in humans, usually occurring in immune-compromised patients. We describe 6 patients with Leuconostoc bacteremia at Dong-A university hospital between 1990 and 2015. One isolate (L. lactis) was identified to species level using 16S rRNA gene sequencing analysis. All patients had underlying diseases and 5 patients underwent procedures that interrupted the normal integumentary defense. Four patients died within 30 days after being identified as carrying Leuconostoc species.
Bacteremia ; Dairy Products ; Genes, rRNA ; Humans ; Leuconostoc ; Vancomycin ; Vancomycin Resistance

Leuconostoc species are gram-positive cocci and they are rarely pathogenic in human. Leuconostoc infections are commonly associated with immunocompromised status and indwelling medical devices include intravenous catheter, tracheostomy, endotracheal intubation and percutaneous endoscopic gastrostomy. Clinical isolates of Leuconostoc were frequently misidentified, usually as viridans streptococci, but they possess inherent resistance to vancomycin despite sensitivity to most other antibiotics. We present a case of Leuconostoc peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD). A 48-year-old man with hypertensive nephropathy has been treated with peritoneal dialysis, developed peritonitis due to Leuconostoc species. The peritonitis was poorly responded to empirical antibiotics. He was successfully treated with intraperitoneal administration of ampicillin. The dialysis catheter was left in place, and continued to function. To our knowledge, this is the first case of Leuconostoc peritonitis reported in Korea.
Ampicillin ; Anti-Bacterial Agents ; Catheters ; Dialysis ; Gastrostomy ; Gram-Positive Cocci ; Humans ; Intubation, Intratracheal ; Korea ; Leuconostoc* ; Middle Aged ; Peritoneal Dialysis ; Peritoneal Dialysis, Continuous Ambulatory* ; Peritonitis* ; Tracheostomy ; Vancomycin ; Viridans Streptococci

D-Mannitol has wide applications in food, pharmaceutical, and chemical industries. In this study, we constructed a genetically stable Escherichia coli strain for D-mannitol production by integrating mannitol dehydrogenase (mdh) and fructose permease (fupL) genes of Leuconostoc pseudomesenteroides ATCC 12291 into chromosome of E. coli ATCC 8739 and inactivating other fermentation pathways (including pyruvate formate-lyase, lactate dehydrogenase, fumarate reductase, alcohol dehydrogenase, methylglyoxal synthase and pyruvate oxidase). Using mineral salts medium with glucose and fructose as carbon sources, the engineered strain could produce 1.2 mmol/L D-mannitol after anaerobic fermentation for 6 days. Based on the coupling of cell growth and D-mannitol production, metabolic evolution was used to improve D-mannitol production. After evolution for 80 generations, D-mannitol titer increased 2.6-fold and mannitol dehydrogenase activity increased 2.8-fold. Genetically stable strains constructed in this work could ferment sugars to produce D-mannitol without the addition of antibiotics, inducers and formate, which was favorable for industrial production.
Escherichia coli ; genetics ; metabolism ; Fermentation ; Industrial Microbiology ; methods ; Leuconostoc ; enzymology ; Mannitol ; metabolism ; Mannitol Dehydrogenases ; genetics ; Metabolic Engineering ; methods ; Monosaccharide Transport Proteins ; genetics

Although Leuconostoc species have rarely been isolated from clinical specimens, this organism may cause invasive infections such as bacteremia and meningitis in immunocompromised patients. We report a case of Leuconostoc garlicum bacteremia in an 84-year-old male with hemovac catheter placement, vancomycin therapy, and inflammatory enterocolitis as underlying risk factors.
Aged, 80 and over ; Bacteremia ; Catheters ; Enterocolitis ; Humans ; Immunocompromised Host ; Leuconostoc ; Male ; Meningitis ; Risk Factors ; Vancomycin

Although Leuconostoc species have rarely been isolated from clinical specimens, this organism may cause invasive infections such as bacteremia and meningitis in immunocompromised patients. We report a case of Leuconostoc garlicum bacteremia in an 84-year-old male with hemovac catheter placement, vancomycin therapy, and inflammatory enterocolitis as underlying risk factors.
Aged, 80 and over ; Bacteremia ; Catheters ; Enterocolitis ; Humans ; Immunocompromised Host ; Leuconostoc ; Male ; Meningitis ; Risk Factors ; Vancomycin

Brain Abscess ; etiology ; Female ; Humans ; Leuconostoc ; pathogenicity ; Male ; Sepsis ; complications ; microbiology