Propionibacterium Strains Research Articles

Exploring the in vitro antimicrobial, antioxidant, and anticancer potentials of Spinifex littoreus Burm f. Merr. against human cervical cancer

Spinifex littoreus Burm f. Merr. is considered as a pharmaceutically important coastal weed whereas, therapeutical applications of this plant are least studied. The current study aimed to identify the antibacterial, antioxidant, and anticancer properties in the chloroform extract of Spinifex littoreus. Six bacterial and 4 fungal human infections were tested for antibacterial activity in the chloroform extract of S. littoreus (SL-CH). The antioxidant ability of SL-CH was screened using the DPPH, ABTS, and H2O2 assays. MTT assay was used to investigate the anticancer activity of SL-CH and ROS, Annexin V, PI, and cell cycle analysis were used to determine its efficacy. The bacterial strain Propionibacterium acnes and the fungal strain Sporothrix schenckii were found to have the largest zones of clearance when the SL-CH extract was used at a concentration of 500 µg/ml. The antioxidant potentials of SL-CH extract showed the maximum radical scavenging activity against ABTS (83.98%), H2O2 (63.73%), and DPPH (52.02%) and their IC50 value was 31.74 ?g/ml, 53.93 ?g/ml, and 139.6 ?g/ml respectively. The IC50 concentration for the chloroform extract of Spinifex littoreus was determined to be 117.5 µg/ml and it showed concentration-dependent anticancer activity against HeLa cells. The ROS fluorescence staining result of SL-CH demonstrated the production of reactive oxygen species, which caused HeLa cells to undergo apoptosis. It was demonstrated by annexin V staining, PI staining technique, and cell cycle analysis that SL-CH extracts caused apoptosis in HeLa cells, preventing their growth. Taken together, these results showed that Spinifex littoreus chloroform extract is rich in antimicrobial, antioxidant, and anticancer potentials. Therefore, Spinifex littoreus extract can treat and prevent various ailments.

Synthesis of Environmental Bioplastic Polyhydroxyalkanoate (PHA) from Waste Glycerol, Palm Oil and Different Concentrations of Glucose by A New Strain Propionibacterium Sp.

Propionibacteria have mainly been found in dairy products and on the skin of humans and animals. This genus classified as non-producing PHA but in this study we show that Propionibacterium sp. can produce PHA. A member of the genus Propionibacterium was isolated from soil. The isolate was identified based on its gram positive pleomorphic rods. Cells occur short chains, singly or in pairs, in V or Y configurations. On mineral salt agar colonies are semi-opaque, convex, glittering and often pigmented in orange in color, biochemical tests and 16SrDNA also done. The 16SrDNA analysis confirmed 85% identity to Propionibacterium (accession number NR 074675.1). The presence of 3HB was identified, based on the analysis of NMR. 13C and 1H NMR analysis confirmed that Propionibacterium sp was able to produce PHA.polymer. These confirm the results of GC. The isolate was then grown on media with waste glycerol (WG), palm oil, different concentration of glucose and one stage and two stages of cultivation. This lead to the conclusion that Propionibacterium is able to grow utilizing waste glycerol, palm oil and different concentration of glucose as the sole carbon source under limited conditions. The PHA content 3 (wt%) and the composition (mol%) and (86% 3HB) when used glucose 2% at frist stage cultivation. while the PHA content 13 (wt %) when used palm oil and 5 (wt%) when utilized (WG), as sole carbon source.

FERMENTATION OF MILK WHEY PERMEATE WITH DIFFERENT DAIRY PROPIONIBACTERIA STRAINS

This research was focused on whey ultrafiltration permeate (UF) fermentation by genetically unmodified (wild) organisms. We chose five classical Propionibacterium (Prb) strains which are attributed to the dairy subclass. The optimal temperature for Prb growth is around 28-30°C, however, for energy saving purposes the aim of this study was to observe the organic acid, especially propionic acid (PA) and biomass production of the chosen Prb (DSM 20273 Acidipropionibacterium acidipropionici = A, DSM 20272 Acidipropionibacterium acidipropionici = B; DSM 4902 Prb. freudenreichii = E; DSM 20535 Acidipropionibacterium jensenii = J; DSM 20276 Acidipropionibacterium thoenii = T) at the room temperature (22±0.5 °C). As expected, all the strains were able to convert lactose into acid, however, with different efficiency, thus the production of PA by Prb is strain-dependent. The higher productivity of PA was observed in samples with strains T, J, and B in a 26-day period, however, it should be noted that also the strain E showed high efficiency in a shorter (6-day) period. The highest concentration of PA was produced by strain T, and it reached 3.7±0.13 g L-1 within 26-day period. The concentration of the PA produced depends on the duration of fermentation, and on the proportions of other acids produced as well. An individual strain initially can produce PA more slowly than others, but over time can be effective, which may be related to adaptation to environmental conditions. We also observed the presence of background microflora in whey permeates – most likely lactic acid bacteria. Lactic acid was produced most rapidly and was the most abundant acid produced from whey UF.

SlpB Protein Enhances the Probiotic Potential of L. lactis NCDO 2118 in Colitis Mice Model.

Bacteria used in the production of fermented food products have been investigated for their potential role as modulators of inflammation in gastrointestinal tract disorders such as inflammatory bowel diseases (IBD) that cause irreversible changes in the structure and function of gut tissues. Ulcerative colitis (UC) is the most prevalent IBD in the population of Western countries, and it is marked by symptoms such as weight loss, rectal bleeding, diarrhea, shortening of the colon, and destruction of the epithelial layer. The strain Propionibacterium freudenreichii CIRM-BIA 129 recently revealed promising immunomodulatory properties that greatly rely on surface-layer proteins (Slp), notably SlpB. We, thus, cloned the sequence encoding the SlpB protein into the pXIES-SEC expression and secretion vector, and expressed the propionibacterial protein in the lactic acid bacterium Lactococcus lactis NCDO 2118. The probiotic potential of L. lactis NCDO 2118 harboring pXIES-SEC:slpB (L. lactis-SlpB) was evaluated in a UC-mice model induced by Dextran Sulfate Sodium (DSS). During colitis induction, mice receiving L. lactis-SlpB exhibited reduced severity of colitis, with lower weight loss, lower disease activity index, limited shortening of the colon length, and reduced histopathological score, with significant differences, compared with the DSS group and the group treated with L. lactis NCDO 2118 wild-type strain. Moreover, L. lactis-SlpB administration increased the expression of genes encoding tight junction proteins zo-1, cln-1, cln-5, ocln, and muc-2 in the colon, increased IL-10 and TGF-β, and decreased IL-17, TNF-α, and IL-12 cytokines in the colon. Therefore, this work demonstrates that SlpB recombinant protein is able to increase the probiotic potential of the L. lactis strain to alleviate DSS-induced colitis in mice. This opens perspectives for the development of new approaches to enhance the probiotic potential of strains by the addition of SlpB protein.

Survival of probiotic strains of microorganisms under imitating digestion in the stomach and intestines of farm animals

The survival rate was studied of the probiotic strains of Lactobacillus plantarum, Lactococcus lactis, Lactobacillus buchneri, Bacillus subtilis and Propionibacterium under in vitro simulation of the digestion in a four-chamber stomach and intestines in farm animals. The model media were prepared on the basis of a phosphate buffer solution and enzyme preparations of acidin-pepsin and cholenzyme. In vitro simulation of the digestion decreased the content of viable bacteria compared with the content of microbes at the beginning of the experiment. The survival rate of probiotic strains of Lactobacillus plantarum, Lactococcus lactis, Lactobacillus buchneri, Bacillus subtilis and Propionibacterium freudenreichii in the model experiment in vitro in the omasum of the farm ruminant mammal animal was high. The application of probiotic strains provides a higher level simulation of the digestion process in the omasum. The content of bacteria after 50 hours from the beginning of experiment was almost as high as after the digestion stage in reticulum. The studied strains under the substitution therapy will allow the necessary number of probiotic microorganisms in the gastrointestinal tract. An animal patient with dysbiosis will achieve a therapeutic effect. The transcendental Biogeogesystem Technique methodology will ensure the safety of the biosphere, providing sustainable high quality food and forage, ensuring the probiotics and prebiotics positive effect on the farm animal and human health.

Coculture method for in vitro cultivation of uncultured oral bacteria.

Purpose:The purpose of the study is to culture uncultured oral bacteria with helper strains using the coculture method from the subgingival plaque samples of chronic periodontitis patients.Materials and Methods:The samples were processed and inoculated on a blood agar medium enriched with hemin and Vitamin K. A helper strain Propionibacterium acnes (ATCC 6919) was cross-streaked across the inoculums to facilitate coculture. The plates were then incubated for 7 days with subsequent subculturing and further incubation.Results:Satellite colonies around helper strain showed one colony type of Porphyromonas gingivalis, one was of nonpigmented Prevotella, three were of Fusobacterium nucleatum and five isolates remained unidentified.Conclusions:Coculture could be used effectively as one of the methods in the isolation and in vitro cultivation of oral bacteria. Incubation using the anaerobic jar technique was found to be economical and efficient for the growth of anaerobic oral bacteria.

Improving propionic acid production from a hemicellulosic hydrolysate of sorghum bagasse by means of cell immobilization and sequential batch operation

Propionic acid (PA) is an important organic compound with extensive application in different industrial sectors and is currently produced by petrochemical processes. The production of PA by large-scale fermentation processes presents a bottleneck, particularly due to low volumetric productivity. In this context, the present work aimed to produce PA by a biochemical route from a hemicellulosic hydrolysate of sorghum bagasse using the strain Propionibacterium acidipropionici CIP 53164. Conditions were optimized to increase volumetric productivity and process efficiency. Initially, in simple batch fermentation, a final concentration of PA of 17.5 g⋅L-1 was obtained. Next, fed batch operation with free cells was adopted to minimize substrate inhibition. Although a higher concentration of PA was achieved (38.0 g⋅L-1 ), the response variables (YP/S = 0.409g⋅g-1 and QP = 0.198 g⋅L-1 ⋅H-1 ) were close to those of the simple batch experiment. Finally, the fermentability of the hemicellulosic hydrolysate was investigated in a sequential batch with immobilized cells. The PA concentration achieved a maximum of 35.3 g⋅L-1 in the third cycle; moreover, the volumetric productivity was almost sixfold higher (1.17g⋅L-1 ⋅H-1 ) in sequential batch than in simple batch fermentation. The results are highly promising, providing preliminary data for studies on scaling up the production of this organic acid.

Anti-Acne Action of Peptides Isolated from Burdock Root-Preliminary Studies and Pilot Testing.

This work aimed to study the anti-bacterial, anti-biofilm and anti-oxidant potential effects of low molecular weight (LMW) peptides (Br-p) isolated from burdock (Arctium lappa L.) roots. We conducted a preliminary study to exclude or confirm the antibiotic activity of the LMW peptides fraction of this plant. Br-p were isolated using gel filtration and a 10 kDa cut-off membrane. The obtained peptides were identified by MALDI TOF/TOF. Antibacterial activity was tested against acne strains using diffusion tests, MIC and MBC. The fibroblast cytotoxicity of Br-p was tested, and the selectivity index (SI) value was determined. The fraction of 46 Br-p peptides isolated from burdock root with a molecular weight below 5000 Da and theoretic pI (isoelectric point) of 3.67–11.83 showed a narrow spectrum of activity against Gram-positive acne bacterial strains. One of the Br-p peptides assessed on MALDI RapidDeNovo was LRCDYGRFFASKSLYDPLKKRR cationic peptide. It was analogous to that contained in A. lappa protein, and theoretically it was matched as a peptide with antibiotic nature. Br-p did not show toxicity to fibroblasts in the tested concentration up to 10 mg/mL, obtaining CC50 10 mg/mL. The SI value for the tested Propionibacterium strains ranged from 160 to 320. Finally, an active dressing based on chitosan/alginate/genipin was prepared using freeze-drying. The formed dressing was evaluated for its anti-acne activity. To sum up: preliminary biological studies confirmed the anti-acne properties of the isolated peptide fraction from burdock root and pointed to the possibility of using it to create an active dressing on the skin.

In Vitro Antimicrobial Activity of Frankincense Oils from Boswellia sacra Grown in Different Locations of the Dhofar Region (Oman).

Frankincense essential oils from Boswellia sacra have been commonly used to treat microbial infections from as early as the 11th century. The main feature of the plant is its gum resin, from which it is possible to obtain essential oils. In the present study, we focused on the comparative study of the oils extracted from the resins of three different Boswellia sacra cultivars (Najdi, Sahli and Houjri). From each of frankincense resin three successive essential oil samples (Grade 1, Grade 2, Grade 3) were obtained. Houjri gum resin gave the lowest percentage (5%) of total essential oil content but showed the maximum number of volatile components in all three grades. Najdi Grade 2 essential oil showed a minimum inhibitory concentration (MIC) of 52 mg/mL toward relevant pathogens Staphylococcus aureus and Pseudomonas aeruginosa, and samples from Grade 2 of Sahily and Houjiri were particularly active against a dermatological strain Propionibacterium acnes, displaying MIC values of 0.264 and 0.66 mg/mL, respectively. Data obtained from in vitro studies showed that all essential oils had a significant antifungal effect against Candida albicans and Malassezia furfur, showing MIC values ranging from 54.56 to 0.246 mg/mL. This work aims to increase the number of substances available in the fight against pathogens and to combat the phenomenon of antibiotic resistance, encouraging the use of alternative resources, especially in non-clinical settings (farms, food processing, etc.).

Engineering Escherichia coli for propionic acid production through the Wood-Werkman cycle.

Native to propionibacteria, the Wood-Werkman cycle enables propionate production via succinate decarboxylation. Current limitations in engineering propionibacteria strains have redirected attention toward the heterologous production in model organisms. Here, we report the functional expression of the Wood-Werkman cycle in Escherichia coli to enable propionate and 1-propanol production. The initial proof-of-concept attempt showed that the cycle can be used for production. However, production levels were low (0.17 mM). In silico optimization of the expression system by operon rearrangement and ribosomal-binding site tuning improved performance by fivefold. Adaptive laboratory evolution further improved performance redirecting almost 30% of total carbon through the Wood-Werkman cycle, achieving propionate and propanol titers of 9 and 5 mM, respectively. Rational engineering to reduce the generation of byproducts showed that lactate (∆ldhA) and formate (∆pflB) knockout strains exhibit an improved propionate and 1-propanol production, while the ethanol (∆adhE) knockout strain only showed improved propionate production.

Regulating colonic dendritic cells by commensal glycosylated large surface layer protein A to sustain gut homeostasis against pathogenic inflammation.

Microbial interaction with the host through sensing receptors, including SIGNR1, sustains intestinal homeostasis against pathogenic inflammation. The newly discovered commensal Propionibacterium strain, P. UF1, regulates the intestinal immunity against pathogen challenge. However, the molecular events driving intestinal phagocytic cell response, including colonic dendritic cells (DCs), by this bacterium are still elusive. Here, we demonstrate that the glycosylation of bacterial large surface layer protein A (LspA) by protein O-mannosyltransferase 1 (Pmt1) regulates the interaction with SIGNR1, resulting in the control of DC transcriptomic and metabolomic machineries. Programmed DCs promote protective T cell response to intestinal Listeria infection and resist chemically induced colitis in mice. Thus, our findings may highlight a novel molecular mechanism by which commensal surface glycosylation interacting with SIGNR1 directs the intestinal homeostasis to potentially protect the host against proinflammatory signals inducing colonic tissue damage.

Neonatal intestinal immune regulation by the commensal bacterium, P. UF1.

Newborns are highly susceptible to pathogenic infections with significant worldwide morbidity possibly due to an immature immune system. Recently, we reported that Propionibacterium strain, P. UF1, isolated from the gut microbiota of preterm infants, induced the differentiation of bacteria-specific Th17 cells. Here, we demonstrate that P. UF1 significantly increased the number of protective Th17 cells and maintained IL-10+ regulatory T cells (Tregs) in newborn mice. In addition, P. UF1 protected mice from intestinal Listeria monocytogenes (L. m) infection. P. UF1 also functionally sustained the gut microbiota and induced critical B vitamin metabolites implicated in the regulation of T cell immunity during L. m intestinal infection. Transcriptomic analysis of P. UF1-induced Th17 cells revealed genes involved in the differentiation and regulation of these cells. These results illustrate the potency of P. UF1 in the enhancement of neonatal host defense against intestinal pathogen infection.

Evaluation of the efficiency of modern schemes of antimicrobial therapy of acne

Acne is the most common cause of patients' treatment of dermatologists. It is known that in the development of the disease, along with the dysfunction of the sebaceous glands of the skin, plays a skin microflora, namely, staphylococci and propionibacteria. In this regard, in the schemes of complex treatment of acne, local medicinal forms of antibiotics are widely used. The aim of the work was to investigate the composition of the microflora contained in the contents of pustules with acne and to study its sensitivity to antibiotics in order to assess the effectiveness of modern methods of treating patients with acne. The contents of the efflorescences of 55 patients with acne have been studied. Isolated and identified 49 strains of bacteria. Their sensitivity to antibiotics of various chemical groups by the disco-diffusion method was investigated. The level of sensitivity to antibiotics was determined by the percentage of sensitive strains among the isolates. Quantitative determination of sensitivity to antibiotics was carried out by serial dilution of preparations in a liquid nutrient medium. It was not possible to isolate bacteria from the contents of pustules in 18.2% of patients. In 77.2% of the examined, microorganisms of the genus Staphylococcus were isolated. In 28.9% of the patients, the propionibacterium was excreted in the contents of vesicular elements in monoculture and in association with staphylococci. The sensitivity of the isolates of staphylococci to beta-lactam antibiotics varied over a wide range and oxacillin was low (34.3%) and high to cefazolin (97.1%). Low sensitivity was isolated strains of staphylococci to antibiotics most commonly used in dermatological practice in integrated circuits acne treatment, namely: clindamycin — 45.7%, chloramphenicol — 34.3%, erythromycin — 17.1%. Similar characteristics of sensitivity to antibiotics are established for isolated strains of propionibacteria. The current state of the antibiotic resistance of microorganisms involved in the development of acne requires the correction of local antibiotic regimens for this disease. Appropriate adjustments should be made based on the results of a study of the sensitivity of the isolated microflora to antiseptics, to which resistance in microorganisms is formed slowly.

Acne Vulgar no Adulto

Introdução: A acne vulgar é uma doença inflamatória crónica da unidade pilossebácea, de etiologia multifatorial. Trata-se de uma das doenças dermatológicas mais comuns. Afeta mais de 85% dos adolescentes, especialmente do género masculino. Apesar de infrequente na idade adulta, dados epidemiológicos recentes mostram uma prevalência crescente, cerca de 40%, predominantemente no género feminino, com impacto negativo na qualidade de vida. A acne do adulto ou acne tardia é uma entidade que está presente após os 25 anos de idade. Classifica-se como acne de início tardio e acne persistente. O tipo persistente é o mais comum, representando 70% a 80% dos casos, e caracteriza-se pela persistência da acne da adolescência, enquanto que a acne de início tardio é definida pela manifestação inaugural após os 25 anos de idade, com uma prevalência de cerca de 20% a 30%.Objetivo: Revisão bibliográfica da literatura científica atual, especialmente focada na fisiopatologia da acne tardia, fatores desencadeantes e agravantes, bem como nas particularidades da sua abordagem terapêutica.Metodologia: Foi utilizada a base de dados MEDLINE-PubMed e foram revistos artigos originais e de revisão bibliográfica publicados entre 2001 e 2017.Discussão: A acne pode ser uma manifestação clínica de doença sistémica, frequentemente endocrinológica, como síndrome do ovário poliquístico, hiperplasia suprarrenal, e tumores secretores virilizantes. É importante considerar estas etiologias, especialmente na mulher e na presença de outros sinais de hiperandrogenismo. Vários estudos apontam outros fatores desencadeantes ou agravantes, nomeadamente fatores genéticos, stress, tabagismo, exposição à radiação ultravioleta, obesidade, dieta hiperglicémica, fármacos, cosméticos, e colonização por estirpes resistentes de Propionibacterium acnes.Conclusão: Na maioria dos casos, a acne do adulto localiza-se na face, tem uma gravidade clínica ligeira a moderada e cursa com níveis hormonais normais. A localização exclusiva no terço inferior da face associa-se mais frequentemente a outros sinais de hiperandrogenismo e a patologia endocrinológica, bem como a um predomínio de lesões inflamatórias. A acne tardia é descrita como potencialmente refratária à terapêutica convencional, sendo muito recidivante. Assim, constitui um desafio terapêutico, que obriga a uma abordagem individualizada.

Antifungal Activity of Lactic Acid Bacteria Combinations in Dairy Mimicking Models and Their Potential as Bioprotective Cultures in Pilot Scale Applications.

Consumer's demand for naturally preserved food products is growing and the use of bioprotective cultures is an alternative to chemical preservatives or a complementary tool to hurdle technologies to avoid or delay fungal spoilage of dairy products. To develop antifungal cultures for the dairy product biopreservation, experiments were conducted both in vitro and in situ. Firstly, the antifungal activity of 32 strains of lactic acid bacteria (LAB) and propionibacteria was screened alone, and then on combinations based on 5 selected lactobacilli strains. This screening was performed in yogurt and cheese models against four major spoilage fungi previously isolated from contaminated dairy products (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Selected combinations were then tested as adjunct cultures in sour cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests against selected fungal targets (P. commune, M. racemosus, and Rhodotorula mucilaginosa) and shelf life tests; and their impact on product organoleptic properties. The screening step allowed selecting two binary combinations, A1 and A3 composed of Lactobacillus plantarum L244 and either Lactobacillus harbinensis L172 or Lactobacillus rhamnosus CIRM-BIA1113, respectively. In situ assays showed that the A1 combination delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2–24 days on sour cream depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106 colony-forming units (CFU)/mL). Moreover, the A1 and A3 combinations also delayed the growth of P. commune in semi-hard cheese for 1–6 days and 1 day, respectively. Antifungal cultures neither impacted the growth of starter cultures in both sour cream and cheese nor the products' pH, although post acidification was observed in sour cream supplemented with these combinations at the highest concentrations (2.107 CFU/mL). The combination of both in vitro and in situ screening assays allowed developing 2 antifungal combinations exhibiting significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products.

Characterizing the Antimicrobial Function of a Dairy-Originated Probiotic, Propionibacterium freudenreichii, Against Multidrug-Resistant Salmonella enterica Serovar Heidelberg in Turkey Poults.

Antimicrobial potential of a dairy-origin probiotic bacteria, Propionibacterium freudenreichii, against multidrug-resistant Salmonella Heidelberg (SH) in turkey poults was determined in the current study. Employing in vitro experiments, two strains (subsp.) of P. freudenreichii: P. freudenreichii freudenreichii B3523 (PF) and P. freudenreichii shermanii B4327 (PS) were tested for their ability to resist low pH (2.5) and bile salts (0.3%). In addition, the ability of the strains to adhere to and invade avian epithelial cells was determined after exposure to Propionibacterium strains followed by SH challenge. Moreover, the antibacterial activity of the strains’ cell-free culture supernatants (CFCSs) were tested against three major foodborne pathogens, including SH. Furthermore, the susceptibility of the strains to common antibiotics used for human therapy was determined. The hemolytic properties of the strains were determined in comparison to Streptococcus pyogenes, a known hemolysis-causing pathogen. Appropriate controls were kept in all studies. Using two in vivo experiments, PF was tested against SH colonization of poult ceca and dissemination to liver and spleen. The four treatment groups were: negative control, PF control (PFC), SH control (SC), and a test group (PFS; PF + SH). The poults in the PFC and PFS groups were inoculated with 1010 CFU ml−1 PF on day 1 through crop gavage and subsequently supplemented through drinking water. On day 7, SC and PFS groups were challenged with SH at 106 CFU ml−1, and after 7 days, cecum, liver, and spleen were collected for determining surviving SH populations. Results indicated that both PF and PS resisted pH = 2.5 and 0.3% bile salts with surviving populations comparable to the control and adhered well onto the avian epithelial cell lines. The strains were susceptible to antibiotics and did not invade the epithelial cells or exhibit hemolytic properties. The CFCSs were highly bactericidal against all tested pathogens. In turkey poults, PF significantly reduced cecal colonization of SH and the dissemination of the pathogen to the liver, compared to the SH challenge controls (P < 0.05). Results revealed that PF, a non-host gastrointestinal tract-derived probiotic, could be an antibiotic alternative to prevent the early colonization of SH in poults, improving the preharvest safety of turkeys.

Dairy propionibacteria as direct-fed microbials: in vitro effect on acid metabolism of Streptococcus bovis and Megasphaera elsdenii

Ruminal acidosis caused by accumulation of lactic acid, a decrease of pH in the rumen and subsequent imbalance of the rumen fermentation process, affects the health and productivity of dairy cows and beef cattle. Direct-fed microbials have potential for use in the control and prevention of ruminal acidosis. This study investigated the interaction between five strains of dairy propionibacteria, Megasphaera elsdenii and Streptococcus bovis in various co-culture combinations in a simulated rumen environment comprising unmodified rumen digesta supplemented with excess glucose. While suppression of lactic acid accumulation by both the dairy propionibacteria and M. elsdenii in the presence of S. bovis in the simulated rumen conditions was evident, propionibacteria were found to be more effective than M. elsdenii in controlling lactic acid levels.

Commensal Propionibacterium strain UF1 mitigates intestinal inflammation via Th17 cell regulation.

Consumption of human breast milk (HBM) attenuates the incidence of necrotizing enterocolitis (NEC), which remains a leading and intractable cause of mortality in preterm infants. Here, we report that this diminution correlates with alterations in the gut microbiota, particularly enrichment of Propionibacterium species. Transfaunation of microbiota from HBM-fed preterm infants or a newly identified and cultured Propionibacterium strain, P. UF1, to germfree mice conferred protection against pathogen infection and correlated with profound increases in intestinal Th17 cells. The induction of Th17 cells was dependent on bacterial dihydrolipoamide acetyltransferase (DlaT), a major protein expressed on the P. UF1 surface layer (S-layer). Binding of P. UF1 to its cognate receptor, SIGNR1, on dendritic cells resulted in the regulation of intestinal phagocytes. Importantly, transfer of P. UF1 profoundly mitigated induced NEC-like injury in neonatal mice. Together, these results mechanistically elucidate the protective effects of HBM and P. UF1-induced immunoregulation, which safeguard against proinflammatory diseases, including NEC.

Antifungal activity of lactic and propionic acid bacteria and their potential as protective culture in cottage cheese

Dairy products are very susceptible to fungal spoilage, which causes economic losses and is a public health concern due to the possible production of mycotoxins. Several novel approaches have been proposed to delay the growth of mold in cheese. Among these, adding a protective culture is particularly interesting in view of increasing consumer demand for naturally preserved foods. The aim of this study was to select a new protective culture and validate its effectiveness as an inhibitor of fungal proliferation in cottage-type cheese. Food-grade bacteria (88 strains) were screened for inhibition of four spoilage molds commonly isolated from cheese. Strains of Propionibacterium and Lactobacillus were the most active. Seven strains were selected and tested further, alone and in pairs, for their abilities to prevent Penicillium chrysogenum growth in a solidified dairy matrix and in cottage cheese. Lactobacillus rhamnosus A238 alone or in combination with Bifidobacterium animalis subsp. lactis A026 inhibited mold growth for at least 21 days at 6 °C, due probably to the production of secondary metabolites and/or competition for nutrients. Overall, our findings show that these strains inhibit molds, some of them acting in synergy, and have potential for use as bio-preservatives in fresh cheese.

Potential influence of dairy propionibacteria on the growth and acid metabolism of Streptococcus bovis and Megasphaera elsdenii.

Ruminal acidosis is a prevalent disorder among dairy cows and feedlot cattle, which can significantly impair their health and productivity. This study, involving seven different strains of dairy propionibacteria, represents an in vitro investigation of the feasibility of using these organisms as direct-fed microbials to control lactic acid acumulation in the rumen. Interactions between the propionibacteria, Streptococcus bovis and Megasphaera elsdenii were evaluated in terms of effects on lactic, acetic and propionic acid metabolism, following co-incubation. Spot resistance tests showed slight but varying degrees of growth inhibition by S. bovis among the propionibacteria, while no inhibition was observed between M. elsdenii and the different strains of dairy propionibacteria. In the co-culture experiments comprising S. bovis in nutrient broth, significant differences in pH and the levels of production of lactic, acetic and propionic acid, were observed between treatments following inoculation with various propionibacteria and/or M. elsdenii. In general, lactic acid concentrations at the end of the incubation were significantly lower in the cultures containing propionibacteria compared with cultures comprising either S. bovis only or S. bovis + M. elsdenii, although efficacy of lactate metabolism varied between species and strains. Moreover,the accumulation of acetic and propionic acid in the combined cultures, but not in the solo S. bovis culture, indicated that these compounds were produced as a result of the metabolism of lactic acid by the propionibacteria and M. elsdenii.