Purification and Physicochemical Characterization of Anti-Gardnerella vaginalis Bacteriocin HV6b Produced by Lactobacillus fermentum Isolate from Human Vaginal Ecosystem

Efficacy of Lactobacillus fermentum Isolated from the Vagina of a Healthy Woman against Carbapenem-Resistant Klebsiella Infections In Vivo

Carbapenem-resistant Enterobacteriaceae (CRE) that produce Klebsiella pneumoniae carbapenemase are increasingly reported worldwide and have become more and more resistant to nearly all antibiotics during the past decade. The emergence of K. pneumoniae strains with decreased susceptibility to carbapenems, which are used as a last resort treatment option, is a significant threat to hospitalized patients worldwide as K. pneumoniae infection is responsible for a high mortality rate in the elderly and immunodeficient individuals. This study used Lactobacillus fermentum as a candidate probiotic for treating CRE-related infections and investigated its effectiveness. We treated mice with L. fermentum originating from the vaginal fluid of a healthy Korean woman and evaluated the Lactobacilli's efficacy in preventive, treatment, non-establishment, and colonization mouse model experiments. Compared to the control, pre-treatment with L. fermentum significantly reduced body weight loss in the mouse models, and all mice survived until the end of the study. The oral administration of L. fermentum after carbapenemresistant Klebsiella (CRK) infection decreased mortality and illness severity during a 2-week observation period and showed that it affects other strains of CRK bacteria. Also, the number of Klebsiella bacteria was decreased to below 5.5 log₁₀ CFU/ml following oral administration of L. fermentum in the colonization model. These findings demonstrate L. fermentum's antibacterial activity and its potential to treat CRE infection in the future.

Effect of Novel Bacteriocinogenic Lactobacillus fermentum BZ532 on Microbiological Shelf-Life and Physicochemical and Organoleptic Properties of Fresh Home-Made Bozai

Bacteriocinogenic Lactobacillus fermentum BZ532 with novel bacteriocin LF-BZ532 was originally isolated from Chinese cereal fermented drink, showing an antimicrobial characteristic during fermentation. This study aimed to explore the in situ antimicrobial activities of L. fermentum BZ532 and co-culturing investigation against key food pathogens, i.e., Staphylococcus aureus and Escherichia coli K-12, was conducted during fresh bozai production. The growth of spoilage bacteria was suppressed and bacterial count was reduced to a significantly low level during 48 h of co-cultures. In situ production of antimicrobial compounds expressed positive activity against S. aureus and E. coli K-12, but negative acitivity against Salmonella sp. D104. The total viable count of bozai BZ-Lf (bozai fermented with BZ532 strain) had a comparatively lower viable count than bozai BZ-C (bozai as an experimental control without BZ532) during storage of 7 days. Titratable acidity of bozai treatments (BZ-C, BZ-Lf) was increased, while pH declined accordingly during storage of 7 days. The organoleptic quality of bozai BZ-C had low sensorial scores as compared with BZ-Lf during storage. In comparison with naturally fermented bozai (BZ-C), L. fermentum BZ532 (BZ-Lf) could significantly reduce the microbial spoilage and extend the shelf-life based on microbiological examination. Conclusively, L. fermentum BZ532 can be used as a bio-protective culture for improving the safety of bozai.

Complete Annotated Genome Sequence of Limosilactobacillus fermentum AGR1487

Limosilactobacillus fermentum is a probiotic species; however, L. fermentum AGR1487 increases colon inflammation in germfree mice and decreases barrier integrity in Caco-2 cells. The AGR1487 genome was sequenced to explore these phenotypes. The genome is a single, circular, 1,939,032-bp chromosome with a G+C content of 52.17% and no plasmids.

Complete Genome Sequence of Lactobacillus fermentum Strain AGR1485, a Human Oral Isolate

Lactobacillus fermentum is found in food products and is generally considered safe. L. fermentum AGR1485 promotes barrier integrity in Caco-2 cells and has genetic similarities to other known probiotic L. fermentum strains. L. fermentum AGR1485 has potential as a probiotic and was sequenced to explore these probiotic properties. The genome is a 2.2-Mbp circular chromosome with no plasmids and a GC content of 51.

Lactobacillus fermentum is found in food products and is generally considered safe. L. fermentum AGR1485 promotes barrier integrity in Caco-2 cells and has genetic similarities to other known probiotic L. fermentum strains. L. fermentum AGR1485 has potential as a probiotic and was sequenced to explore these probiotic properties. The genome is a 2.2-Mbp circular chromosome with no plasmids and a GC content of 51.15%.

Biofilm Forming Lactobacillus: New Challenges for the Development of Probiotics

Probiotics are live bacteria, generally administered in food, conferring beneficial effects to the host because they help to prevent or treat diseases, the majority of which are gastrointestinal. Numerous investigations have verified the beneficial effect of probiotic strains in biofilm form, including increased resistance to temperature, gastric pH and mechanical forces to that of their planktonic counterparts. In addition, the development of new encapsulation technologies, which have exploited the properties of biofilms in the creation of double coated capsules, has given origin to fourth generation probiotics. Up to now, reviews have focused on the detrimental effects of biofilms associated with pathogenic bacteria. Therefore, this work aims to amalgamate information describing the biofilms of Lactobacillus strains which are used as probiotics, particularly L. rhamnosus, L. plantarum, L. reuteri, and L. fermentum. Additionally, we have reviewed the development of probiotics using technology inspired by biofilms.

Bacteriocin-Producing Lactic Acid Bacteria Isolated from Mangrove Forests in Southern Thailand as Potential Bio-Control Agents: Purification and Characterization of Bacteriocin Produced by Lactococcus lactis subsp. lactis KT2W2L

The aim of this work was to purify and characterize the bacteriocin produced by Lactococcus lactis subsp. lactis KT2W2L previously isolated from mangrove forests in southern Thailand, in order to evaluate its potential as new food protective agent. The active peptide from the cell-free supernatant of this strain was purified in 4 steps: (1) precipitation with 70 % saturated ammonium sulfate, (2) elution on a reversed-phase cartridge using different concentrations of acetonitrile, (3) cation-exchange chromatography and (4) final purification by reversed-phase HPLC on a C8 column. The molecular mass of 3,329.5254 Da of the purified bacteriocin, determined by mass spectrometry, is nearly identical to that of peptide nisin Z. The activity of the purified bacteriocin was unaffected by pH (2.0-10.0), thermostable but was sensitive to proteolytic enzymes. The bacteriocin activity was stable after 8 weeks of storage at -20 °C and 7 weeks of storage at 4 °C, but decreased after 3 weeks of storage at 37 °C. It was stable when incubated for 1 month at 4 °C in 0-30 % NaCl. Inhibitory spectrum of this bacteriocin showed a wide range of activity against similar bacterial strains, food-spoilage and food-borne pathogens. L. lactis subsp. lactis KT2W2L was sensitive to kanamycin, penicillin and tetracycline but resistant to ampicillin, gentamicin and vancomycin. The fragment obtained after amplification of genomic DNA from L. lactis subsp. lactis KT2W2L, with specific primers for bacteriocin genes, presented 99 % homology to the nisin Z gene. PCR amplification demonstrated that L. lactis subsp. lactis KT2W2L does not harbor virulence genes cylA, cylB, efaAfs and esp. The bacteriocin and its producing strain may find application as bio-preservatives for reduction in food-spoilage and food-borne pathogens in food products.

Probiotic characteristics of Lactobacillus fermentum strains isolated from tulum cheese

The aim of this study was to characterize the probiotic characteristics of Lactobacillus fermentum strains isolated from Tulum cheese. Seven L. fermentum strains were selected among the isolated and identified lactobacillus strains due to their abundance. When the gastric condition was considered, L. fermentum LP3 and LP4 were able to tolerate pH 2.5 and 1% bile salt. All L. fermentum strains had similar enzymatic activity and antibiotic resistance pattern but the highest antagonistic effect was detected within LP3, LP4 and LP6. Cholesterol assimilation amount of L. fermentum strains ranged between 12.1 and 45.3% in MRS and 20.7-71.1% in MRS with bile. The highest cholesterol assimilation in MRS and MRS with bile was occurred by LP3 and LP4, respectively. L. fermentum LP2 adhered to caco-2 cells more than Lactobacillus rhamnosus LGG where LP3, LP4 and LP5 adhered at similar level. In conclusion, L. fermentum LP3 and LP4 fulfilled sufficient criteria to be probiotics for use as a starter culture in the production of tulum cheese or other dairy products. Also this study indicated that some food-associated Lactobacillus strains non-predominant for gut biota have significant probiotic potential.