scholarly journals In vitro investigations of the effect of probiotics and prebiotics on selected human intestinal pathogens

2002 ◽  
Vol 39 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Laura J. Fooks ◽  
Glenn R. Gibson
Keyword(s):  
Intestinal Pathogens

scholarly journals Functional and Genomic Characterization of Ligilactobacillus salivarius TUCO-L2 Isolated From Lama glama Milk: A Promising Immunobiotic Strain to Combat Infections

2020 ◽  
Vol 11 ◽  
Author(s):  
Sandra Quilodrán-Vega ◽  
Leonardo Albarracin ◽  
Flavia Mansilla ◽  
Lorena Arce ◽  
Binghui Zhou ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Functional Characterization ◽  
Comparative Genomic ◽  
Cytokines And Chemokines ◽  
Isolation And Characterization ◽  
Intestinal Pathogens ◽  
Lama Glama

Potential probiotic or immunobiotic effects of lactic acid bacteria (LAB) isolated from the milk of the South American camelid llama (Lama glama) have not been reported in published studies. The aim of the present work was to isolate beneficial LAB from llama milk that can be used as potential probiotics active against bacterial pathogens. LAB strains were isolated from llama milk samples. In vitro functional characterization of the strains was performed by evaluating the resistance against gastrointestinal conditions and inhibition of the pathogen growth. Additionally, the adhesive and immunomodulatory properties of the strains were assessed. The functional studies were complemented with a comparative genomic evaluation and in vivo studies in mice. Ligilactobacillus salivarius TUCO-L2 showed enhanced probiotic/immunobiotic potential compared to that of other tested strains. The TUCO-L2 strain was resistant to pH and high bile salt concentrations and demonstrated antimicrobial activity against Gram-negative intestinal pathogens and adhesion to mucins and epithelial cells. L. salivarius TUCO-L2 modulated the innate immune response triggered by Toll-like receptor (TLR)-4 activation in intestinal epithelial cells. This effect involved differential regulation of the expression of inflammatory cytokines and chemokines mediated by the modulation of the negative regulators of the TLR signaling pathway. Moreover, the TUCO-L2 strain enhanced the resistance of mice to Salmonella infection. This is the first report on the isolation and characterization of a potential probiotic/immunobiotic strain from llama milk. The in vitro, in vivo, and in silico investigation performed in this study reveals several research directions that are needed to characterize the TUCO-L2 strain in detail to position this strain as a probiotic or immunobiotic that can be used against infections in humans or animals, including llama.

scholarly journals Transcriptional Analysis of the grlRA Virulence Operon from Citrobacter rodentium

2010 ◽  
Vol 192 (14) ◽  
pp. 3722-3734 ◽  
Author(s):  
Marija Tauschek ◽  
Ji Yang ◽  
Dianna Hocking ◽  
Kristy Azzopardi ◽  
Aimee Tan ◽  
...  
Keyword(s):  
Core Promoter ◽  
Regulatory Protein ◽  
Transcriptional Analysis ◽  
Upstream Region ◽  
Citrobacter Rodentium ◽  
Dnase I Footprinting ◽  
Intestinal Pathogens ◽  
Enterocyte Effacement

ABSTRACT The locus for enterocyte effacement (LEE) is the virulence hallmark of the attaching-and-effacing (A/E) intestinal pathogens, namely, enteropathogenic Escherichia coli, enterohemorrhagic E. coli, and Citrobacter rodentium. The LEE carries more than 40 genes that are arranged in several operons, e.g., LEE1 to LEE5. Expression of the various transcriptional units is subject to xenogeneic silencing by the histone-like protein H-NS. The LEE1-encoded regulator, Ler, plays a key role in relieving this repression at several major LEE promoters, including LEE2 to LEE5. To achieve appropriate intracellular concentrations of Ler in different environments, A/E pathogens have evolved a sophisticated regulatory network to control ler expression. For example, the LEE-encoded GrlA and GrlR proteins work as activator and antiactivator, respectively, of ler transcription. Thus, control of the transcriptional activities of the LEE1 (ler) promoter and the grlRA operon determines the rate of transcription of all of the LEE-encoded virulence factors. To date, only a single promoter has been identified for the grlRA operon. In this study, we showed that the non-LEE-encoded AraC-like regulatory protein RegA of C. rodentium directly stimulates transcription of the grlRA promoter by binding to an upstream region in the presence of bicarbonate ions. In addition, in vivo and in vitro transcription assays revealed a σ70 promoter that is specifically responsible for transcription of grlA. Expression from this promoter was strongly repressed by H-NS and its paralog StpA but was activated by Ler. DNase I footprinting demonstrated that Ler binds to a region upstream of the grlA promoter, whereas H-NS interacts specifically with a region extending from the grlA core promoter into its coding sequence. Together, these findings provide new insights into the environmental regulation and differential expressions of the grlR and grlA genes of C. rodentium.

scholarly journals The Acute Host-Response of Turkeys Colonized With Campylobacter coli

2021 ◽  
Vol 8 ◽  
Author(s):  
Matthew J. Sylte ◽  
Sathesh K. Sivasankaran ◽  
Julian Trachsel ◽  
Yuko Sato ◽  
Zuowei Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Platelet Aggregation ◽  
Expression Profiles ◽  
Mitigation Strategies ◽  
Cytokine Gene Expression ◽  
Campylobacter Coli ◽  
Anatomical Site ◽  
Post Inoculation ◽  
Intestinal Pathogens

Consumption of contaminated poultry products is one of the main sources of human campylobacteriosis, of which Campylobacter jejuni subsp. jejuni (C. jejuni) and C. coli are responsible for ~98% of the cases. In turkeys, the ceca are an important anatomical site where Campylobacter asymptomatically colonizes. We previously demonstrated that commercial turkey poults colonized by C. jejuni showed acute changes in cytokine gene expression profiles, and histological intestinal lesions at 2 days post-inoculation (dpi). Cecal tonsils (CT) are an important part of the gastrointestinal-associated lymphoid tissue that surveil material passing in and out of the ceca, and generate immune responses against intestinal pathogens. The CT immune response toward Campylobacter remains unknown. In this study, we generated a kanamycin-resistant C. coli construct (CcK) to facilitate its enumeration from cecal contents after experimental challenge. In vitro analysis of CcK demonstrated no changes in motility when compared to the parent isolate. Poults were inoculated by oral gavage with CcK (5 × 107 colony forming units) or sterile-media (mock-colonized), and euthanized at 1 and 3 dpi. At both time points, CcK was recovered from cecal contents, but not from the mock-colonized group. As a marker of acute inflammation, serum alpha-1 acid glycoprotein was significantly elevated at 3 dpi in CcK inoculated poults compared to mock-infected samples. Significant histological lesions were detected in cecal and CT tissues of CcK colonized poults at 1 and 3 dpi, respectively. RNAseq analysis identified 250 differentially expressed genes (DEG) in CT from CcK colonized poults at 3 dpi, of which 194 were upregulated and 56 were downregulated. From the DEG, 9 significantly enriched biological pathways were identified, including platelet aggregation, response to oxidative stress and negative regulation of oxidative stress-induced intrinsic apoptotic signaling pathway. These data suggest that C. coli induced an acute inflammatory response in the intestinal tract of poults, and that platelet aggregation and oxidative stress in the CT may affect the turkey's ability to resist Campylobacter colonization. These findings will help to develop and test Campylobacter mitigation strategies to promote food safety in commercial turkeys.

Biological activity of the non-microbial fraction of kefir: antagonism against intestinal pathogens

2017 ◽  
Vol 84 (3) ◽  
pp. 339-345 ◽  
Author(s):  
Carolina Iraporda ◽  
Mário Abatemarco Júnior ◽  
Elisabeth Neumann ◽  
Álvaro Cantini Nunes ◽  
Jacques R Nicoli ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Biological Activity ◽  
Cell Model ◽  
Acetic Acid Bacteria ◽  
Fermented Milk ◽  
In Vitro Assays ◽  
Intestinal Epithelial ◽  
Milk Fermentation ◽  
Intestinal Pathogens

Kefir is a fermented milk obtained by the activity of kefir grains which are composed of lactic and acetic acid bacteria, and yeasts. Many beneficial health effects have been associated with kefir consumption such as stimulation of the immune system and inhibition of pathogenic microorganisms. The biological activity of kefir may be attributed to the presence of a complex microbiota as well as the microbial metabolites that are released during fermentation. The aim of this work was to characterise the non-microbial fraction of kefir and to study its antagonism againstEscherichia coli,Salmonellaspp. andBacillus cereus.During milk fermentation there was a production of organic acids, mainly lactic and acetic acid, with a consequent decrease in pH and lactose content. The non-microbial fraction of kefir added to nutrient broth at concentrations above 75% v/v induced a complete inhibition of pathogenic growth that could be ascribed to the presence of un-dissociated lactic acid. In vitro assays using an intestinal epithelial cell model indicated that pre-incubation of cells with the non-microbial fraction of kefir did not modify the association/invasion ofSalmonellawhereas pre-incubation ofSalmonellawith this fraction under conditions that did not affect their viability significantly decreased the pathogen's ability to invade epithelial cells. Lactate exerted a protective effect againstSalmonellain a mouse model, demonstrating the relevance of metabolites present in the non-microbial fraction of kefir produced during milk fermentation.

scholarly journals Replacement coliform flora in carriers of intestinal pathogens

1964 ◽  
Vol 62 (1) ◽  
pp. 39-44
Author(s):  
G. T Stewart ◽  
R. J Holt ◽  
H. M. T Coles ◽  
K. M Bhat
Keyword(s):  
Drug Resistant ◽  
E Coli ◽  
Intestinal Pathogens

Eight carriers of intestinal pathogens (5 Salm. typhi-murium, 2 Sh. sonnei, 1 E. coli 026) were given their own coliforms, rendered drug-resistant in vitro to neomycin or paromomycin, together with one of these drugs. In seven cases, the drug-resistant coliform flora established itself, while the natural coliform flora and the pathogen were suppressed. In four cases only (2 Sh. sonnei, 2 Salm. typhi-murium) the pathogen was eliminated in the course of this procedure.

scholarly journals Inactivation of the Tulane Virus, a Novel Surrogate for the Human Norovirus

2013 ◽  
Vol 76 (4) ◽  
pp. 712-718 ◽  
Author(s):  
PENG TIAN ◽  
DAVID YANG ◽  
CHRISTINA QUIGLEY ◽  
MARISSA CHOU ◽  
XI JIANG
Keyword(s):  
Tissue Culture ◽  
High Titer ◽  
Virus Titer ◽  
Short Exposure ◽  
Heat Denaturation ◽  
Blood Group Antigens ◽  
Murine Norovirus ◽  
Tulane Virus ◽  
Intestinal Pathogens

Human noroviruses (HuNoVs) are the major cause of nonbacterial gastroenteritis epidemics. The culturable feline calicivirus and murine norovirus have been used extensively as surrogates to study HuNoV biology, as HuNoV does not grow in vitro. Additional efforts to identify new surrogates are needed, because neither of these common surrogates are truly intestinal pathogens. The newly described Tulane virus (TV) is a typical calicivirus, it is isolated from macaque stools, is cultivable in vitro, and recognizes human histo-blood group antigens. Therefore, TV is a promising surrogate for HuNoVs. In this study, we evaluated the resistance or stability of TV under various physical and environmental conditions by measuring a 50% reduction of tissue culture infective dose (TCID50) by using a TV cell culture system. Due to the nature of this virus, it is hard to produce a high-titer stock through tissue culture. In our study, the maximal reduction in virus titers was 5 D (D = 1 log) in heat-denaturation and EtOH experiments, and 4 D in UV, chlorine, and pH-stability experiments. Therefore in this study, we defined the inactivation of TV as reaching a TCID50/ml of 0 (a 4- to 5-D reduction in TCID50, depending on the detection limit). TV was inactivated after incubation at 63°C for 5 min, incubation at 56°C for 30 min (5 D), exposure to 60 mJ/cm2 of UVC radiation (4 D), or incubation at 300 ppm of free chlorine for 10 min (4 D). TV was shown to be stable from pH 3.0 to 8.0, though an obvious reduction in virus titer was observed at pH 2.5 and 9.0, and was inactivated at pH 10.0 (4 D). TV was resistant to a low concentration of EtOH (40% or lower) but was fully inactivated (5 D) by 50 to 70% EtOH after a short exposure (20 s). In contrast, quantitative real-time PCR was unable to detect, or poorly detected, virus titer reductions between treated and untreated samples described in this study.

scholarly journals Coalho cheese as source of probiotic lactic acid bacteria

2020 ◽  
Vol 9 (8) ◽  
pp. e266984958
Author(s):  
Cristiane Pereira de Lima ◽  
Giselle Maria Pereira Dias ◽  
Maria Taciana Cavalcanti Vieira Soares ◽  
Laura Maria Bruno ◽  
Ana Lucia Figueiredo Porto
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bile Salt ◽  
Bile Salt Hydrolase ◽  
In Vitro Tests ◽  
16S Rrna Sequence ◽  
Probiotic Potential ◽  
Functional Product ◽  
Intestinal Pathogens

The aim of this study was to characterize the probiotic potential of 24 lactic acid bacteria (LAB) strains isolated from artisanal Coalho cheese from Pernambuco, Brazil by in vitro tests. The gastrointestinal tract (GIT) resistance, antimicrobial activity against intestinal pathogens, autoaggregation and coaggregation capacity, cell hydrophobicity, ß-galactosidase activity, deconjugate bile salt activity for the production of bile salt hydrolase (BSH), and the sensitivity to antibiotics were evaluated. Of the 24 strains, 22 remained viable to a simulated GIT. Two LAB inhibited the growth of Listeria monocytogenes and two inhibited Escherichia coli. The autoaggregation rate ranged from 27% to 96%, and the strains were able to coaggregate with Staphylococcus aureus and E. coli reaching levels between 58% and 47%, respectively. The hydrophobicity percentage ranged from 5% to 57%. Four strains were able to produce BSH. One LAB was able to produce up to 604 Miller units of ß-galactosidase. All strains were sensitive to five antibiotics and only two were resistant to vancomycin (30μg) and norfloxacin (10g). LAB strains which were able to overcome all barriers with a reduction of only one log cycle and LAB strains which were able to produce ß-galactosidase were identified by 16S rRNA sequence analysis as Lactococcus lactis subsp. Lactis, Enterococcus durans, and Enterococcus faecium. The evaluated LAB showed promising probiotic characteristics. Strains identified as L. lactis subsp. Lactis were selected for studies involving their technological potential to investigate the possible use of these microorganisms into a functional product.

scholarly journals A new phenothiazine derivate is active against Clostridioides difficile and shows low cytotoxicity

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258207
Author(s):  
Troels Ronco ◽  
Francisca Maria Aragao ◽  
Lasse Saaby ◽  
Jørn B. Christensen ◽  
Anders Permin ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Experimental Studies ◽  
Clinical Importance ◽  
Oral Exposure ◽  
Minimal Bactericidal Concentration ◽  
Phenothiazine Derivative ◽  
Minimal Inhibition Concentration ◽  
Clostridioides Difficile ◽  
Intestinal Pathogens

The rapid evolution of antibiotic resistance in Clostridioides difficile and the consequent effects on prevention and treatment of C. difficile infections (CDIs) are matters of concern for public health. Thioridazine, a compound belonging to the phenothiazine group, has previous shown antimicrobial activity against C. difficile. The purpose of this present study was to investigate the potential of a novel phenothiazine derivative, JBC 1847, as an oral antimicrobial for treatment of intestinal pathogens and CDIs. The minimal inhibition concentration and the minimum bactericidal concentration of JBC 1847 against C. difficile ATCC 43255 were determined 4 μg/mL and high tolerance after oral administration in mice was observed (up to 100 mg/kg bodyweight). Pharmacokinetic modeling was conducted in silico using GastroPlusTM, predicting low (< 10%) systemic uptake after oral exposure and corresponding low Cmax in plasma. Impact on the intestinal bacterial composition after four days of treatment was determined by 16s rRNA MiSeq sequencing and revealed only minor impact on the microbiota in non-clinically affected mice, and there was no difference between colony-forming unit (CFU)/gram fecal material between JBC 1847 and placebo treated mice. The cytotoxicity of the compound was assessed in Caco-2 cell-line assays, in which indication of toxicity was not observed in concentrations up to seven times the minimal bactericidal concentration. In conclusion, the novel phenothiazine derivative demonstrated high antimicrobial activity against C. difficile, had low predicted gastrointestinal absorption, low intestinal (in vitro) cytotoxicity, and only induced minor changes of the healthy microbiota, altogether supporting that JBC 1847 could represent a novel antimicrobial candidate. The clinical importance hereof calls for future experimental studies in CDI models.

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