scholarly journals Antagonistic activity of Lactobacillus reuteri strains isolated from different niches against food bacteria and its biopreservative application along with nisin in milk system

2019 ◽  
Vol 72 (05) ◽  
pp. 489-498
Author(s):  
Diwas Pradhan ◽  
Nirmal Kumar ◽  
Priya Singh ◽  
Pooja Gujjar
Keyword(s):  
Lactobacillus Reuteri ◽  
Antagonistic Activity ◽  
Food Bacteria

scholarly journals Selection of Promising Lactobacilli Antagonistic to Campylobacter Jejuni

2019 ◽  
Vol 9 (1) ◽  
pp. 3983-3986
Keyword(s):  
Lactobacillus Plantarum ◽  
Campylobacter Jejuni ◽  
New Technologies ◽  
Lactobacillus Reuteri ◽  
Antagonistic Activity ◽  
Bacterial Strains ◽  
Opportunistic Bacteria ◽  
Wide Range ◽  
Selection Of

This article reflects the results of a study on the selection of promising lactobacilli antagonistic to Campilobacter jejuni, a strain that is the most common and more pathogenic for humans, carried out as part of a project to scientifically substantiate the use of new technologies in poultry feeding using special probiotic strains that increase productivity and obtaining poultry products of improved quality with the properties of functional food products. During the study, strains of lactic acid bacteria were obtained. The cultivation of strains of Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus fermentum, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus plantarum was carried out on liquid and agarized nutrient media MRS at 370С for 24 hours. In vitro antagonistic studies were performed using the two-way antagonistic method on a wide range of indicator crops. Since there is evidence of a specific mechanism for the manifestation of the antagonistic activity of lactobacilli to gram-negative and gram-positive bacteria, we used test strains of both groups of bacteria. The antagonistic activity of the studied cultures against pathogenic and opportunistic bacteria was determined by the zone of growth inhibition of indicator strains around the colonies of individual strains of lactobacilli and their consortium (in mm). Priority clinical isolates isolated from birds with intestinal infections were used as indicator cultures: Proteus vulgaris, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Campylobacter jejuni and Campylobacter jejuni ATCC strains 33560. During the study, most bacterial strains of the genus Lactobacillus were highly antagonistic its activity against indicator strains. The most sensitive to the inhibitory effect of lactobacilli were E. coli, Campylobacter jejuni, S. typhimurium and P. vulgaris. The research results showed that the strain L.plantarum ATCC 8014 exhibits a more pronounced antagonistic activity than other strains of lactobacilli.

scholarly journals Antagonistic Activity of Bacteriocins Produced by Lactobacillus Isolates against Multidrug Resistant Pathogens

2021 ◽  
pp. 76-87
Author(s):  
Asma Bashir ◽  
Kashif Ali
Keyword(s):  
Lactobacillus Reuteri ◽  
Raw Milk ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Proteinase K ◽  
Diffusion Method ◽  
Multi Drug Resistance ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Lactobacillus Spp

Background: Multi drug-resistance pose a great threat to public health and are responsible for various life-threatening ailments. There is a crucial need to control the outbreaks by finding alternatives to the conventional drugs available. Over the last few years, the usage of probiotics, including Lactobacillus spp. and their bacteriocins has gained much attention to ward off various diseases. Methods: This study was focused on characterizing bacteriocins extracted from Lactobacillus spp. and assessing their antagonistic effect against multi-drug resistant bacteria. Fifteen Lactobacillus spp. were isolated and identified from Pakistani dairy and fermented products (raw milk, cheese, butter milk, pickle and yoghurt). All the isolates were preliminarily screened by the antagonism method of agar well diffusion method, and the bacteriocins were isolated by ammonium sulphate method. Afterwards, to evaluate the release of bacteriocin in liquid medium, the Cell-Free Supernatant Fluid (CFSF) of the best producer strains were tested by agar well diffusion assay. To assess the thermostability of the bacteriocins, they were subjected to temperatures of 40ᴼC, 60ᴼC, 80ᴼC and 100ᴼC. Results: The study allowed the selection of five bacteriocin producing strains Lactobacillus acidophilus KAL1, Lactobacillus casei KAL3, Lactobacillus plantarum KAL5, Lactobacillus reuteri KAL6 and Lactobacillus spp. delbrukei KAL7, endowed with the strongest and broadest inhibitory ability against both Gram-positive (Methicillin Resistant Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria. Bacteriocins isolated were significantly thermostable with activity at 80ᴼC (30, 20 min) respectively. Moreover, all the bacteriocins were considerably stable at a range of pH (4–8) but all the activity was eliminated against proteolytic enzyme Proteinase K. Conclusion: From this study, it was concluded that bacteriocin extracts from five isolated Lactobacillus spp. can be considered a preferable candidate against multi-drug resistant pathogens. These partially purified bacteriocins should be further processed to attain purified product that could be useful for further studies for the control of pathogens, food spoilage and preservation purposes.

scholarly journals Efficacy of Lactobacillus reuteri in clinical practice

2021 ◽  
Vol 4 (3) ◽  
pp. 277-283
Author(s):  
O.N. Komarova ◽  
Keyword(s):  
Clinical Practice ◽  
Immune System ◽  
Gut Microbiota ◽  
Lactobacillus Reuteri ◽  
Antagonistic Activity ◽  
Mucosal Barrier ◽  
Quantitative Composition ◽  
Infantile Colic ◽  
Gut Colonization ◽  
Premature Babies

This paper addresses the primary aspects of developing gut microbiota and the immune system and the role of gut microbiocenosis in this process. Optimal gut colonization and adequate immune response are critical factors in developing tolerance to commensal microbes and anti-infectious protection. The authors highlight various prenatal, neonatal, and postnatal factors which prevent normal colonization of gastrointestinal mucosa. One of the methods to restore the qualitative and quantitative composition of gut microbiota are probiotics. Probiotics demonstrating antagonistic activity for pathogens compete with these pathogens for the adhesion to mucosal epithelium and nutrients, thereby inhibiting the production of bacterial toxins, modulating the functions of the immune system, improving gut microbiocenosis, maintaining the integrity of the gastrointestinal mucosal barrier, and controlling gut inflammation. Probiotics are a heterogeneous group of living bacteria with species- and strain-specific properties. For example, Lactobacillus reuteri is an effective probiotic commonly prescribed in premature babies, children with acute gastroenteritis, and infantile colic. KEYWORDS: gut microbiota, microbiocenosis, premature, C-section, probiotics, bacteria, immune system, infantile colic, Lactobacillus reuteri. FOR CITATION: Komarova O.N. Efficacy of Lactobacillus reuteri in clinical practice. Russian Journal of Woman and Child Health. 2021;4(3):277–283 (in Russ.). DOI: 10.32364/2618-8430-2021-4-3-277-283.

scholarly journals Isolation, characterization, and assessment of lactic acid bacteria toward their selection as poultry probiotics

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Rine Christopher Reuben ◽  
Pravas Chandra Roy ◽  
Shovon Lal Sarkar ◽  
Rubayet-Ul Alam ◽  
Iqbal Kabir Jahid
Keyword(s):  
Lactic Acid ◽  
Epithelial Cells ◽  
Lactic Acid Bacteria ◽  
Inhibitory Activity ◽  
Antibiotic Susceptibility ◽  
Lactobacillus Reuteri ◽  
Health Benefit ◽  
Antagonistic Activity ◽  
Probiotic Properties ◽  
Antibiotic Susceptibility Test

Abstract Background Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, are now accepted as suitable alternatives to antibiotics in the control of animal infections and improving animal production. Lactic acid bacteria (LAB) with remarkable functional properties have been evaluated in different studies as possible probiotic candidates. The purpose of this study was to isolate, characterize and assess the potentials of LAB from poultry gastrointestinal tract as potential poultry probiotics. Results Potential LAB probiotics were isolated from broilers, characterized and evaluated for probiotic properties including antagonistic activity (against Escherichia coli, E. coli O157: H7, Enterococcus faecalis, Salmonella Typhimurium, S. Enteritidis and Listeria monocytogenes), survivability in simulated gastric juice, tolerance to phenol and bile salts, adhesion to ileum epithelial cells, auto and co-aggregation, hydrophobicity, α–glucosidase inhibitory activity, and antibiotic susceptibility tests. Most promising LAB strains with excellent probiotic potentials were identified by API 50 CHL and 16S rRNA sequencing as Lactobacillus reuteri I2, Pediococcus acidilactici I5, P. acidilactici I8, P. acidilactici c3, P. pentosaceus I13, and Enterococcus faecium c14. They inhibited all the pathogens tested with zones of inhibition ranging from 12.5 ± 0.71 to 20 ± 0 mm, and competitively excluded (P < 0.05) the pathogens examined while adhering to ileum epithelial cells with viable counts of 3.0 to 6.0 Log CFU/ml. The selected LAB strains also showed significant (P < 0.005) auto and co-aggregation abilities with α-glucosidase inhibitory activity ranging from 12.5 to 92.0%. The antibiotic susceptibility test showed 100.00% resistance of the LAB strains to oxacillin, with multiple antibiotic resistance indices above 0.5. Conclusion The selected LAB strains are ideal probiotic candidates which can be applied in the field for the improvement of poultry performance and control of pathogens in poultry, hence curtailing further transmission to humans.

scholarly journals Study of the In Vitro Antagonistic Activity of Various Single-Strain and Multi-Strain Probiotics against Escherichia coli

2018 ◽  
Vol 15 (7) ◽  
pp. 1539 ◽  
Author(s):  
Sabina Fijan ◽  
Dunja Šulc ◽  
Andrej Steyer
Keyword(s):  
Escherichia Coli ◽  
Adjuvant Therapy ◽  
Lactobacillus Reuteri ◽  
Antagonistic Activity ◽  
Spot Test ◽  
In Vitro Tests ◽  
Public Health Perspective ◽  
Single Strain ◽  
E Coli

Escherichia coli is an important commensal of our gut, however, many pathogenic strains exist, causing various severe infections in the gut or beyond. Due to several antibiotic resistance patterns of E. coli, research of alternative treatments or adjuvant therapy is important. One of these is the use of probiotics as antagonistic agents against E. coli. Most published studies investigate only one strain of E. coli and single-strain probiotics. The objectives of this study were to evaluate the antagonistic activity of selected single-strain and multi-strain probiotic supplements against selected clinical E. coli pathotypes using the in vitro agar spot test and the co-culturing method. Molecular methods were used to determine the presence of the genus lactobacilli and bifidobacteria as well as certain selected strains in the probiotic supplements. The agar-spot test showed that the multi-strain probiotics were more effective than the single-strain probiotics. On the other hand, the co-culturing method showed the opposite result, indicating that results are importantly influenced by the chosen method. The most effective single-strain probiotics against E. coli strains were Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus reuteri DSM 17938. The most effective multi-strain probiotics contained lactobacilli, bifidobacteria and enterococci strains, thus proving that most effective probiotics against E. coli strains are the lactic acid bacteria and bifidobacteria. The overall results from both in vitro tests reveal that all selected probiotics exhibited an antagonistic activity against all E. coli strains. From a public health perspective probiotics have thus proved to be successful in inhibiting the growth of E. coli and could therefore be used as adjuvant therapy or alternative therapy in E. coli infections.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

Leaf surface and endophytic fungi associated with onion leaves and their antagonistic activity against Alternaria porri.

2015 ◽  
Vol 67 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Sobhy I. I. Abdel-Hafez ◽  
Kamal A. M. Abo-Elyousr ◽  
Ismail R. Abdel-Rahim
Keyword(s):  
Endophytic Fungi ◽  
Leaf Surface ◽  
Antagonistic Activity ◽  
Alternaria Porri
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