Beneficial Lactic Acid Bacteria Research Articles

High level aminoglycoside resistance in Enterococcus, Pediococcus and Lactobacillus species from farm animals and commercial meat products

Inappropriate use of aminoglycosides in animal husbandry has led to the selection and emergence of high-level aminoglycoside resistance (HLAR) in lactic acid bacteria (LAB). The objective of this study was to assess the presence of aminoglycoside resistant LAB in farm animals and meat products. Gentamicin resistant LAB (n = 138) were selectively isolated from 50 different meat and farm animal sources. These native isolates of LAB were subsequently characterized for their minimum inhibitory concentration to seven different aminoglycoside antibiotics. HLAR to gentamicin, kanamycin and streptomycin was found to be 38 %, 45 % and 15 %, respectively. Selected cultures of LAB were identified by random amplified polymorphic DNA (RAPD)-PCR and 16S rDNA gene sequencing. Subsequent detection for the presence of nine aminoglycoside modifying genes [aac(6′)Ie-aph(2″)Ia, aph(3′)IIIa, aad6, ant(6)Ia, ant(9)Ia, ant(9)Ib, aph(2″)Ib, aph(2″)Ic and aph(2″)Id] was carried out by PCR. The Enterococcus spp. (n = 64) and Lactobacillus plantarum (n = 6) isolated from farm animals and chicken sausages, respectively, were positive for the bifunctional gene, aac(6′)Ie-aph(2″)Ia in PCR. In addition, Enterococcus sp. (n = 17), Lactobacillus plantarum (n = 3), and Pediococcus lolii (n = 2) possessed the kanamycin resistance gene, aph(3′)IIIa. Other LAB viz. Enterococcus faecalis (n = 2), E. faecium (n = 2) and L. plantarum (n = 1) harbored the streptomycin resistance gene, aad6. The integrase (int) gene, characteristic to Tn 916-Tn 1545 was detected in Enterococcus faecalis CS11+ and Enterococcus cecorum I40a suggesting its involvement in antibiotic resistant gene transfer. Besides, strains of L. plantarum, a species used as probiotic, isolated in this study showed the occurrence of aph(3′)IIIa as well as aac (6′)Ie-aph(2″)Ia genes that could be of concern in human health. The findings of the study highlight the spread and emergence of multi-resistance genes for aminoglycoside antibiotics among beneficial LAB.

Chronic ethanol consumption alters intestinal microbiota composition (MUC9P.746)

Abstract It is well known that chronic alcohol consumption leads to organ damage and increased susceptibility to bacterial and viral infections. Ethanol exposure in the intestinal lumen alters tight junction proteins leading to disruption of the epithelial barrier. Increased permeability in turn leads to translocation of gut-derived endotoxins causing inflammatory responses in the liver that contribute to alcoholic liver disease. Recent studies have shown that gut mucosa homeostasis is also modulated by the microbiome. Disruptions in the gut microbiome have been described for many diseases including IBD, diabetes and colon cancer. In order to gain a better understanding of the dose-dependent effects of ethanol on the gut microbiome, we performed ribosomal RNA sequencing to determine the differentially expressed bacteria in the small and large intestine in a rhesus macaque model of voluntary ethanol self-administration. In the colon we observed a 2-fold increase in heavy drinkers compared to nondrinkers in the phylum Bacteroidetes that subsequently results in a decrease in Firmicutes, the phylum containing most beneficial lactic acid bacteria. In the duodenum, jejunum, ileum and colon we found a 3-fold decrease in the commensal species Lactobacillus intestinalis and a 2-fold increase in the potential pathogenic species Prevotella copri in heavy drinkers compared to nondrinkers. These studies are likely to reveal mechanisms of ethanol-related gut dysregulation and related inflammation.

Preparation and characterization of antimicrobial cationized peptides from barley (Hordeum vulgare L.) proteins

In the current study barley protein hydrolysate was cationized using polyethyleneimine and the physicochemical and antimicrobial properties of the modified peptides were investigated. Degree of substitution and zeta potential analysis verified the high proportion of positively charged components. Antimicrobial assay showed that cationized peptides effectively inhibited non-beneficial bacterial growth (Escherichia coli JM109 and Micrococcus luteus (ATCC 4698)) at low concentration (98–195 μg/mL), while higher concentration levels (390–1560 μg/mL) were required to inhibit the growth of beneficial lactic acid bacteria (Lactobacillus reuteri (ATCC 23272) and Lactococcus lactis MG 1363). Structural studies revealed the unordered open structures as the major structural elements of cationized peptides which resulted in conformational flexibility. Highly exposed hydrophobic segments accompanied by the chain flexibility could positively contribute to adsorption and penetration of cationized peptides into bacterial membrane. These unique structural characteristics of barley proteins in combination with positively charged side chains confer potential antimicrobial activity to barley-derived peptides which can be applied to enhance the shelf life stability of food, feed and other products.

The recalcitrance of oxalate, nitrate and nitrites during the controlled lactic fermentation of commonly consumed green leafy vegetables

Purpose – Green leafy vegetables (GLVs) are important components of a balanced diet especially in developing countries where the major requirements of micronutrients are met. However, GLVs also contain significant amounts of oxalate, nitrate and nitrites, whose role in the human diet is constantly changing. The current study explored the behavior of nitrate, nitrites and oxalate in lactic-fermented GLVs with an intention to develop functional foods based on them. Design/methodology/approach – Selected strains of beneficial lactic acid bacteria were used for the controlled fermentation of GLV, while an identical portion was subjected to spontaneous fermentation. The nitrate and nitrites were monitored spectrophotometrically, while oxalate contents were quantified by both titrimetric and by high-performance liquid chromatography throughout the duration of fermentation. Findings – More than 90 per cent of individual constituents studied remained intact in the GLVs paste after the six-day controlled fermentation period. However, there was significant difference between the controlled and spontaneously fermented samples in terms of oxalate, nitrate and nitrite contents. Originality/value – Controlled lactic fermentation although superior in all other aspects may not be able to lower the anti-nutrients present. The advantages of spontaneous fermentation vis-à-vis controlled fermentation are discussed. The work will bring out the importance of the beneficial effects of GLVs and the effect of lactic fermentation.

Evaluation of beneficial Lactic Acid Bacteria strains as a potential probiotic for the prevention of bovine mastitis

Evaluation of beneficial Lactic Acid Bacteria strains as a potential probiotic for the prevention of bovine mastitis

Artisanal Coalho cheeses as source of beneficial Lactobacillus plantarum and Lactobacillus rhamnosus strains

Based on screening for potential beneficial lactic acid bacteria from Coalho cheese produced in the North-East region of Brazil, eight strains belonging to Lactobacillus rhamnosus and Lactobacillus plantarum were selected. All investigated strains presented low levels of hydrophobicity. Different levels of coaggregation were observed for tested Lb. rhamnosus and Lb. plantarum with Listeria monocytogenes. All strains were able to grow in presence of 0.5% of the sodium salts of taurocholic acid (TC), taurodeoxycholic acid (TDC), and glycocholic acid (GC) and showed the ability to deconjugate only TC, TDC, and GC. Investigated Lb. rhamnosus and Lb. plantarum strains showed good survival when exposed to the conditions simulating the GIT conditions. Lb. rhamnosus and Lb. plantarum strains were tested for presence of virulence, antibiotic resistance, and biogenic amine production genes. In addition, minimum inhibititory concentration (MIC) of selected antibiotics was determined. Production of antimicrobial peptides (bacteriocins) was investigated. However, only Lb. rhamnosus EM253 produced bacteriocin at level 800 arbitrary unit (AU) mL−1 against L. monocytogenes 211. The bacteriocin remained stable at pH from 2.0 to 10.0 and after exposure at 100 °C for 120 min and in presence of surfactants and salts. Studied Lb. rhamnosus and Lb. plantarum strains showed good potential to be applied as a functional coculture/s with beneficial properties in the production of Coalho cheese.

Pyrosequencing analysis of microbiota reveals that lactic acid bacteria are dominant in Korean flat fish fermented food, gajami-sikhae.

The gajami-sikhae, traditional Korean cuisine fermented with flat fish, samples were collected from eight different manufacturers (GS1-GS8). We employed pyrosequencing method to analyze the bacterial communities of the gajami-sikhae samples. Family- and genus-level analyses indicated that the bacterial community compositions of GS3 and GS6 were distinct from those of the rest. The species-level structures of bacterial communities of the gajami-sikhae samples except for GS3 and GS6 featured Lactobacillus sakei as the most abundant species. Leuconostoc mesenteroides was revealed as the most dominant species among the bacterial community of GS6 and the bacterial community of GS3 was composed of various lactic acid bacteria. We employed a culture-based method to isolate beneficial strains from the gajami-sikhae samples. However, most of the 47 selected colonies were identified as Bacillus subtilis and Bacillus amyloliquefaciens. This study indicated that gajami-sikhae was mainly composed of many beneficial lactic acid bacteria.

Traditional Fermented Products – A good Source for Beneficial Lactic Acid Bacteria

Traditional Fermented Products – A good Source for Beneficial Lactic Acid Bacteria

In vitro selection and characterization of new probiotic candidates from table olive microbiota.

To date, only a few studies have investigated the complex microbiota of table olives in order to identify new probiotic microorganisms, even though this food matrix has been shown to be a suitable source of beneficial lactic acid bacteria (LAB). Two hundred and thirty eight LAB, belonging to Lactobacillus plantarum, Lactobacillus pentosus and Leuconostoc mesenteroides species, and isolated from Nocellara Etnea table olives, have been screened in this survey through an in vitro approach. A simulation of transit tolerance in the upper human gastrointestinal tract, together with autoaggregation and hydrophobicity, have been decisive in reducing the number of LAB to 17 promising probiotics. None of the selected strains showed intrinsic resistances towards a broad spectrum of antibiotics and were therefore accurately characterized on an undifferentiated and 3D functional model of the human intestinal tract made up of H4-1 epithelial cells. As far as the potential colonization of the intestinal tract is concerned, a high adhesion ratio was observed for Lb. plantarum O2T60C (over 9%) when tested in the 3D functional model, which closely mimics real intestinal conditions. The stimulation properties towards the epithelial barrier integrity and the in vitro inhibition of L. monocytogenes adhesion and invasion have also been assessed. Lb. plantarum S1T10A and S11T3E enhanced trans-epithelial electrical resistance (TEER) and therefore the integrity of the polarized epithelium in the 3D model. Moreover, S11T3E showed the ability to inhibit L. monocytogenes invasion in the undifferentiated epithelial model. The reduction in L. monocytogenes infection, together with the potential enhancement of barrier integrity and an adhesion ratio that was above the average in the 3D functional model (6.9%) would seem to suggest the Lb. plantarum S11T3E strain as the most interesting candidate for possible in vivo animal and human trials.

Agar films containing green tea extract and probiotic bacteria for extending fish shelf-life

A bioactive film composed of agar, incorporating green tea extract and probiotic strains (Lactobacillus paracasei L26 and Bifidobacterium lactis B94) was applied on hake fillets in order to evaluate the effect of the films during 15 days of storage. Hake was previously inoculated with Shewanella putrefaciens and Photobacterium phosphoreum (103–104 CFU/g) to simulate a spoilage process. The green tea and/or probiotic film provoked a reduction, particularly of H2S-producing bacteria counts and total viable bacteria throughout the storage period. The probiotic strains added to the film could pass to the fish producing an increment of lactic acid bacterial counts, even in the presence of green tea extract. The effect of the films also caused a decrease in the indexes of fish quality (total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N) and pH). The total viable counts, H2S-producing microorganisms and TVB-N were maintained below the limits of acceptability during 15 days for the fillet covered with the green tea + probiotic film, compared to the rest of the samples. Films with green tea and probiotic were able to extend shelf-life of hake at least for a week and increase the beneficial lactic acid bacteria in fish.

Who will win the race in childrens' oral cavities? Streptococcus mutans or beneficial lactic acid bacteria?

Adhesion to oral soft and hard tissue is crucial for bacterial colonisation in the mouth. The aim of this work was to select strains of oral lactic acid bacteria that could be used as probiotics for oral health. To this end, the adhesive properties of some lactic acid bacteria were investigated. Seventeen lactic acid bacteria including two Streptococcus mutans strains were isolated from the oral cavity of healthy children, while other strains were isolated from fermented meat products. The bacterial strains were applied to teeth surfaces covered with saliva or without saliva. A significant diversity in adhesion capacity to teeth surfaces among the lactic acid bacteria was observed. Lactic acid bacteria isolated from the oral cavity adhered the best to teeth surfaces covered with saliva, whereas lactic acid bacteria isolated from fermented meat samples adhered the best to tooth surface without saliva. All strains of lactic acid bacteria were able to reduce the number of S. mutans cells, in particular on saliva-coated tooth surface. Therefore, they might have potential as probiotics for the oral cavity.

The investigation of probiotic potential of lactic acid bacteria isolated from cow milk

Probiotic strains can be isolated from many sources, for human applications one of the main criteria is being mammal origin. Cow milk is an important nutrient source for human. Lot of studies showed that this fluid has beneficial effects on the health of human. One reason of being beneficial is explaining by the microflora of cow milk including beneficial lactic acid bacteria. In this research work, 12 isolate were identified as lactic acid bacteria by biochemical characterization and further studied for probiotic activity. Among them 9 lactic acid bacteria was posseses probiotic activity. Six Lactobacilli stains were identified as Lactobacillus gasseri(1),Lactobacillus rhamnosus(1),Lactobacillus fermentum(2),Lactobacillus viridescens(3),Lactobacillus farciminis(1), Lactobacillus buchner(4). All of the bacilli isolates were selected to observe potential probiotic activity. These isolates showed resistance to stomach pH (pH 3.0), tolerance against 0.3% bile salt concentration and antimicrobial activity against Escherichia coli, Salmonella enteritids, Staphylococcus aureus, Listeria monocytogenes. The isolates were used to investigate the tolerances of the isolates to other stress conditions, such as, growth at different NaCl solution, growth at different temperatures and in the presence of 0.5% CaCO3. All of the isolate showed good tolerances in stress conditions. After investigation the probiotic properties of these isolates, they were identified by biochemical characterization techniques. It is observed that, cow milk is a source of potential probiotic strains.

Isolation, Characterization, Determination of Probiotic Properties of Lactic Acid Bacteria from Human Milk

s: Probiotic mean live microorganisms that have beneficial effects on their host's health. Although probiotic strains can be isolated from many sources; for human applications the main criteria is being human origin. Breast milk is an important nutrient source for neonates. Lots of studies showed that this fluid has beneficial effects on the health of neonates. One reason of being beneficial is explaining by the micro flora of human breast milk including beneficial lactic acid bacteria. In this study, isolates were identified by biochemical and molecular characterization and also probiotic properties of lactic acid bacteria, isolated from human milk were investigated. Two of the isolates were observed as potential probiotic. Two of them are bacilli. These isolates showed resistance to stomach pH (pH 3.0), tolerance against 0,3% bile concentration and antimicrobial activity against, Escherichia coli, Bacillus ceruse and Staphylococcus aureus and. After investigation the probiotic properties of these isolates, they were identified by biochemical characterization techniques and molecular identification by using Polymeric chain Reaction (PCR) of 16S ribosomal RNA (rRNA) and 16S sequencing. Two lactobacilli were identified as Lactobacillus rhamnosus (KF477283) and Lactobacillus casei. (KF477282) In the light of this study, it is observed that, human milk is a source of potential probiotic strains.

Effect of Mannoproteins on the Growth, Gastrointestinal Viability, and Adherence to Caco‐2 Cells of Lactic Acid Bacteria

Yeast cell wall (YCW) preparations and yeast mannoprotein extracts have been effective against some enteropathogenic bacteria as Campylobacter jejuni, Escherichia coli, and Salmonella, and they can affect the population of beneficial lactic acid bacteria (LAB). In this work, we studied the effect of a mannoprotein extract on five strains of LAB. This extract was metabolised by the bacteria, enhancing their survival in simulated gastrointestinal juice, and increasing the adherence of Lactobacillus plantarum, L. salivarius, and Enterococcus faecium to Caco-2 cells. Yeast mannoproteins are promising naturally occurring compounds that could be used to enhance LAB intestinal populations and control pathogens.

Bioactivity of the Essential Oil of an Argentine Collection of Acanthospermum hispidum (Asteraceae)

The essential oil of an Argentine collection of the annual herb Acanthospermum hispidum DC. (Asteraceae), which contains the sesquiterpenoids beta-caryophyllene (35.2%), alpha-bisabolol (11.4%), and germacrene D (11.1%) as major constituents, displayed molluscicidal effects on an adult population of Biomphalaria peregrina Orbigny (LD50 37.8 microg/mL) and produced alteration of the feeding and oviposition behavior of the polyphagous insect Spodoptera frugiperda Smith when incorporated in the larval diet at 250 microg/g. In addition, a selective antibacterial activity was observed against pathogenic strains of Staphylococcus aureus and Enterococcus faecalis (MICs 62.5 and 125 microg/mL), but was inactive at 125 microg/mL against three beneficial lactic acid bacteria. Synergistic interactions were further validated by FIC index determination of the combination of the antibiotics oxacillin and gentamicin and the essential oil on the four pathogenic strains evaluated.

Antimicrobial Activity of an Amazon Medicinal Plant (Chancapiedra) (Phyllanthus niruri L.) against Helicobacter pylori and Lactic Acid Bacteria

The potential of water extracts of the Amazon medicinal plant Chancapiedra (Phyllanthus niruri L.) from Ecuador and Peru for antimicrobial activity against Helicobacter pylori and different strains of lactic acid bacteria such as Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus plantarum was investigated. H. pylori was inhibited by both water extracts in a dose dependent manner, whereas lactic acid bacterial growth was not affected. Both extracts contained ellagic acid and hydroxycinnamic acid derivatives and exhibited high free radical scavenging linked-antioxidant activities (89%). However, gallic acid was detected only in the Ecuadorian extract. Preliminary studies on the mode of action of Chancapiedra against H. pylori revealed that inhibition may not involve proline dehydrogenase-based oxidative phosphorylation inhibition associated with simple mono-phenolics and could involve ellagitannins or other non-phenolic compounds through a yet unknown mechanism. This study provides evidence about the potential of Chancapiedra for H. pylori inhibition without affecting beneficial lactic acid bacteria.

Inhibitory Potential of Tea Polyphenolics and Influence of Extraction Time Against Helicobacter pylori and Lack of Inhibition of Beneficial Lactic Acid Bacteria

Tea polyphenolics such as catechins are known to have the potential to inhibit many bacterial pathogens. Helicobacter pylori has been identified as an etiologic agent in the development of gastric ulcer, peptic ulcer, gastritis, and many other stomach-related diseases. In this study, we investigated the effect of 9 tea extracts--3 different brands representing 4 different processed types (white, green, oolong, and black)--on the inhibition of H. pylori. Extraction times of 2 and 5 minutes were compared. Most 5-minute extracts showed H. pylori inhibition, whereas 2-minute extracts only of Choice darjeeling black and Tazo white showed inhibition. No recovery was observed after the addition of 0.5 and 5 mM proline, indicating that tea polyphenols do not inhibit H. pylori by inhibition of proline oxidation via proline dehydrogenase. Extracts that showed inhibition were further evaluated for their effect on beneficial lactic acid bacteria. None of the samples showed inhibition, suggesting that tea might be able to inhibit H. pylori without affecting the beneficial lactic acid bacteria. High-performance liquid chromatography indicated the presence of gallic acid, quercetin, caffeine, and tea catechins (including catechin, epicatechin, and epigallocatechin) in all the tea samples. Our study indicates that tea can be potentially used as a low-cost dietary support to combat H. pylori-linked gastric diseases without affecting the beneficial intestinal bacteria.

Probiotics – do they have a role in the pig industry?

The delivery of certain living microorganisms in food has long been suggested as having positive health effects in humans. This practice has extended into food animal production, with a variety of microorganisms being used; lactic acid bacteria, various Bacillus species and the yeast Saccharomyces cerevisiae have been particularly used in the pig industry. The increased interest in probiotics is essentially due to the problem of microbial resistance to antibiotics and following the ban of the use of antibiotics in animal production, probiotics being considered an alternative means to reduce pathogen infection and improve animal health especially around the time of weaning. However, there is still a need to clarify the probiotic effectiveness in pigs, and the underlying mechanisms. When assessing the efficacy of probiotics one must consider the particular strain of organism being used and the production stage of the pigs being treated. The reproducible delivery of probiotics in industrial pig production is problematic as maintenance of viability is key to their beneficial activity, but difficult to achieve with commonly used feed processing technologies. One specific context where probiotics organisms may be reliably delivered is in systems utilising fermented liquid feeds. Liquid feed may be fermented by the activity of wild lactic acid bacteria or may be stimulated using specific isolates as ‘starters’; the latter system has advantages in terms of reproducibility and speed of fermentation. The farm context in which the organism is used is likely to be critical; the use of probiotics is more likely to result in measurable economic gains in animals living in sub-optimal conditions rather than in those reared in the highest welfare and husbandry conditions. The establishment of a beneficial lactic acid bacteria population at birth may lead to healthier animals, this may be most effectively achieved by treating sows, which provide an amplification step and flood the neonatal pigs’ environment with desirable bacterial strains. In contrast, it may be sufficient to provide a supportive, protective microbiota around the time of weaning as this is a time of major crisis with instability and loss of certain bacterial populations.

Harnessing functional food strategies for the health challenges of space travel—Fermented soy for astronaut nutrition

Astronauts face numerous health challenges during long-duration space missions, including diminished immunity, bone loss and increased risk of radiation-induced carcinogenesis. Changes in the intestinal flora of astronauts may contribute to these problems. Soy-based fermented food products could provide a nutritional strategy to help alleviate these challenges by incorporating beneficial lactic acid bacteria, while reaping the benefits of soy isoflavones. We carried out strain selection for the development of soy ferments, selecting strains of lactic acid bacteria showing the most effective growth and fermentation ability in soy milk (Streptococcus thermophilus ST5, Bifidobacterium longum R0175 and Lactobacillus helveticus R0052). Immunomodulatory bioactivity of selected ferments was assessed using an in vitro challenge system with human intestinal epithelial and macrophage cell lines, and selected ferments show the ability to down-regulate production of the pro-inflammatory cytokine interleukin-8 following challenge with tumour necrosis factor-alpha. The impact of fermentation on vitamin B1 and B6 levels and on isoflavone biotransformation to agluconic forms was also assessed, with strain variation-dependent biotransformation ability detected. Overall this suggests that probiotic bacteria can be successfully utilized to develop soy-based fermented products targeted against health problems associated with long-term space travel.

Soybean whey enhance mineral balance and caecal fermentation in rats

Soybean whey, a by-product of tofu manufacturing, is currently discarded by the food industry. However, it contains valuable compounds such as non-digestible oligosaccharides (NDO), which promote the growth of beneficial lactic acid bacteria in the colon, and are therefore recognized as prebiotics. Acidic fermentation of NDO in the caecum appears to be related with an increase in mineral absorption. To evaluate the effect of consuming soybean whey containing galacto-oligosaccharides (GOS) on mineral absorption and caecal fermentation in rats. An in vivo assay was carried out in rats over a period of 4 weeks; previously, the nutritional composition of soybean whey was determined and NDO were measured by high-performance liquid chromatography (HPLC). Faeces and urine were collected weekly throughout the experiment for mineral balance analyses. Animals were killed under anaesthesia, organs were removed and weighed, and short-chain fatty acids in the caecal contents were determined by gas chromatography. Non-digestible carbohydrates such as GOS stachyose (318 +/- 3 mg/100 mL) and traces of inulin were identified by HPLC. When soybean whey was used as a source of GOS in rats, the consumption of diluted soybean whey (75 mL/day per rat) containing GOS (120 mg/day per rat) exhibited a prebiotic effect and led to an improved mineral balance, especially for calcium and magnesium. In view of its composition and potential health-promoting properties, soybean whey could be used as a valuable ingredient in new functional foods.