6 results on '"Greppi, Anna"'
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2. Anaerobutyricum hallii promotes the functional depletion of a food carcinogen in diverse healthy fecal microbiota.
- Author
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Garcia, Alejandro Ramirez, Greppi, Anna, Constancias, Florentin, Ruscheweyh, Hans-Joachim, Gasser, Julie, Hurley, Katherine, Sturla, Shana J., Schwab, Clarissa, and Lacroix, Christophe
- Subjects
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ENTEROTYPES , *HUMAN microbiota , *SHORT-chain fatty acids , *CARCINOGENS , *FUNCTIONAL foods - Abstract
Introduction: Anaerobutyricum hallii is a human gut commensal that transforms the heterocyclic amine 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), a carcinogen from cooked meat. The transformation mechanism involves the microbial production of acrolein from glycerol, and its conjugation with PhIP, thus blocking its mutagenic potential. A potential cancer prevention strategy could therefore involve supplementing complex human microbial communities with metabolically competent bacteria such as A. hallii that can deplete PhIP. However, it has not been established how the proportion of A. hallii in diverse healthy human gut microbial communities relates to functional capacity for PhIP transformation and, moreover, how supplementing microbiomes with A. hallii affects this function. Methods: In this study, shotgun metagenomics was used to study taxonomic profiling, the abundance of glycerol/diol dehydratase (gdh)-harboring taxa, the proportion of resident A. hallii, and the reconstruction of A. hallii population genomes in the fecal samples of 20 healthy young adult donors. Furthermore, the influence of supplementing 106 cells/mL of A. hallii DSM 3353 with diluted fecal microbiota was characterized. Results and discussion: Six microbiota were assigned to Bacteroides, nine to Prevotella, and five to Ruminococcus by enterotype-associated clustering. The total number of gdh copies in the 20 fecal microbiota expressed per 1010 bacterial cells ranged between 1.32 × 108 and 1.15 × 109. Eighteen out of the 20 donors were dominated by A. hallii, representing between 33% and 94% of the total gdh relative abundance of the samples. Themicrobiota with low A. hallii abundance (i.e., with a relative abundance < 1%) transformed less PhIP than the microbiota with high A. hallii abundance (i.e., with a relative abundance > 1%). Furthermore, supplementing the low-A. hallii-abundantmicrobiota with glycerol significantly increased the PhIP transformation capacity after 6 h while reducing total short-chain fatty acid (SCFA) levels, which is most likely due to acrolein production. Although acetate decreased in allmicrobiota with glycerol and with the combination of glycerol and A. hallii, for most of the microbiomes, butyrate production increased over time. Thus, for a significant number of diverse healthy human fecal microbiomes, and especially when they have little of the taxa to start with, supplementing A. hallii increases PhIP transformation. These findings suggest the need to test in vivo whether supplementing microbiomes with A. hallii reduces PhIP exposure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Anaerobutyricum hallii promotes the functional depletion of a food carcinogen in diverse healthy fecal microbiota.
- Author
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Ramirez Garcia, Alejandro, Greppi, Anna, Constancias, Florentin, Ruscheweyh, Hans-Joachim, Gasser, Julie, Hurley, Katherine, Sturla, Shana J., Schwab, Clarissa, and Lacroix, Christophe
- Subjects
- *
ENTEROTYPES , *HUMAN microbiota , *SHORT-chain fatty acids , *CARCINOGENS , *FUNCTIONAL foods - Abstract
Introduction: Anaerobutyricum hallii is a human gut commensal that transforms the heterocyclic amine 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), a carcinogen from cooked meat. The transformation mechanism involves the microbial production of acrolein from glycerol, and its conjugation with PhIP, thus blocking its mutagenic potential. A potential cancer prevention strategy could therefore involve supplementing complex human microbial communities with metabolically competent bacteria such as A. hallii that can deplete PhIP. However, it has not been established how the proportion of A. hallii in diverse healthy human gut microbial communities relates to functional capacity for PhIP transformation and, moreover, how supplementing microbiomes with A. hallii affects this function. Methods: In this study, shotgun metagenomics was used to study taxonomic profiling, the abundance of glycerol/diol dehydratase (gdh)-harboring taxa, the proportion of resident A. hallii, and the reconstruction of A. hallii population genomes in the fecal samples of 20 healthy young adult donors. Furthermore, the influence of supplementing 106 cells/mL of A. hallii DSM 3353 with diluted fecal microbiota was characterized. Results and discussion: Six microbiota were assigned to Bacteroides, nine to Prevotella, and five to Ruminococcus by enterotype-associated clustering. The total number of gdh copies in the 20 fecal microbiota expressed per 1010 bacterial cells ranged between 1.32 × 108 and 1.15 × 109. Eighteen out of the 20 donors were dominated by A. hallii, representing between 33% and 94% of the total gdh relative abundance of the samples. Themicrobiota with low A. hallii abundance (i.e., with a relative abundance < 1%) transformed less PhIP than the microbiota with high A. hallii abundance (i.e., with a relative abundance > 1%). Furthermore, supplementing the low-A. hallii-abundantmicrobiota with glycerol significantly increased the PhIP transformation capacity after 6 h while reducing total short-chain fatty acid (SCFA) levels, which is most likely due to acrolein production. Although acetate decreased in allmicrobiota with glycerol and with the combination of glycerol and A. hallii, for most of the microbiomes, butyrate production increased over time. Thus, for a significant number of diverse healthy human fecal microbiomes, and especially when they have little of the taxa to start with, supplementing A. hallii increases PhIP transformation. These findings suggest the need to test in vivo whether supplementing microbiomes with A. hallii reduces PhIP exposure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Isolation and Comparative Genomic Analysis of Reuterin-Producing Lactobacillus reuteri From the Chicken Gastrointestinal Tract
- Author
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Greppi, Anna, Asare, Paul Tetteh, Schwab, Clarissa, Zemp, Niklaus, Stephan, Roger, Lacroix, Christophe, University of Zurich, and Lacroix, Christophe
- Subjects
Microbiology (medical) ,chicken ,2404 Microbiology ,Lactobacillus reuteri ,lcsh:QR1-502 ,reuterin ,610 Medicine & health ,comparative genomics ,Microbiology ,2726 Microbiology (medical) ,lcsh:Microbiology ,570 Life sciences ,biology ,antimicrobial ,Reuterin ,Antimicrobial ,Chicken ,Comparative genomics ,10082 Institute of Food Safety and Hygiene - Abstract
Lactobacillus reuteri is a natural inhabitant of selected animal and human gastrointestinal tract (GIT). Certain strains have the capacity to transform glycerol to 3-hydroxypropionaldehyde (3-HPA), further excreted to form reuterin, a potent antimicrobial system. Reuterin-producing strains may be applied as a natural antimicrobial in feed to prevent pathogen colonization of animals, such as in chicken, and replace added antimicrobials. To date, only seven L. reuteri strains isolated from chicken have been characterized which limits phylogenetic studies and host-microbes interactions characterization. This study aimed to isolate L. reuteri strains from chicken GIT and to characterize their reuterin production and antimicrobial resistance (AMR) profiles using phenotypic and genetic methods. Seventy strains were isolated from faces, crops and ceca of six chicken from poultry farms and samples from slaughterhouse. Twenty-five strains were selected for further characterization. Draft genomes were generated for the new 25 isolates and integrated into a phylogenetic tree of 40 strains from different hosts. Phylogenetic analysis based on gene content as well as on core genomes showed grouping of the selected 25 L. reuteri chicken isolates within the poultry/human lineage VI. Strains harboring pdu-cob-cbi-hem genes (23/25) produced between 156 mM ± 11 and 330 mM ± 14 3-HPA, from 600 mM of glycerol, in the conditions of the test. All 25 chicken strains were sensitive to cefotaxime (MIC between 0.016 and 1 μg/mL) and penicillin (MIC between 0.02 and 4 μg/mL). Akin to the reference strains DSM20016 and SD2112, the novel isolates were resistant to penicillin, possibly associated with identified point mutations in ponA, pbpX, pbpF and pbpB. All strains resistant to erythromycin (4/27) carried the ermB gene, and it was only present in chicken strains. All strains resistant to tetracycline (5/27) harbored tetW gene. This study confirms the evolutionary history of poultry/human lineage VI and identifies pdu-cob-cbi-hem as a frequent trait but not always present in this lineage. L. reuteri chicken strains producing high 3-HPA yield may have potential to prevent enteropathogen colonization of chicken., Frontiers in Microbiology, 11, ISSN:1664-302X
- Published
- 2020
5. Decontamination of Minimally-Processed Fresh Lettuce Using Reuterin Produced by <italic>Lactobacillus reuteri</italic>.
- Author
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Asare, Paul T., Greppi, Anna, Stettler, Martina, Schwab, Clarissa, Stevens, Marc J. A., and Lacroix, Christophe
- Subjects
LETTUCE ,LACTOBACILLUS reuteri ,ACROLEIN - Abstract
Over the last years the demand for pre-washed, fresh-cut, and minimally-processed (MP) produce has increased. MP fresh vegetable are rapidly spoiled, whereas there is consumers’ concern about chemical disinfection treatments such as with chlorine. A promising antimicrobial is reuterin, a broad-spectrum-antimicrobial compound produced by food-grade
Lactobacillus reuteri from glycerol. In aqueous solution, reuterin is a dynamic system consisting of 3-hydroxypropionaldehyde (3-HPA), its hydrate, its dimer as well as acrolein, which was recently identified as the main antimicrobial component of the system. Here, we tested the use of reuterin containing similar 3-HPA levels but different acrolein concentrations for decontaminating and preserving fresh-cut lettuce. Crude reuterin (CR) was produced by biotransformation of 600 mM glycerol usingL. reuteri DSM 20016T. CR preparations were further incubated for 16 h at 50°C to produce enhanced reuterin (ER) with raised concentration of acrolein. Fresh-cut iceberg lettuce (Lactuca sativa) was washed using CR (1.5–1.9 mM acrolein) and ER (7.2–21.9 mM acrolein) solutions at 4°C, or sodium hypochloride (250 mg/L) and tap water, and compared with unwashed lettuce. Washed lettuce samples were packed under modified atmosphere (2% O2 , 5% CO2 , and 93% N2 ) and stored for 13 days at 4°C. Application of ER containing 12.1, 20.9, or 21.9 mM acrolein reduced the initial viable plate counts ofEnterobacteriaceae (by 2.1–2.8 log CFU/g), and yeasts and molds (by 1.3–2.0 log CFU/g) when compared with unwashed samples. In contrast, reuterin solutions containing 7.2 mM acrolein, sodium hypochlorite and tap water only showed very limited and transient, or no effects on the cell loads of lettuce after washing and during storage. Visual assessment of leaves washed with ER showed acrolein concentration-dependent discoloration noticeable already after 3 days of storage for the highest acrolein concentrations. Discoloration became severe for all ER treatments after 7 days, while the other treatments preserved the aspect of washed lettuce. Our data show the predominant role of acrolein as the main antimicrobial component of the reuterin system for food biopreservation. Reuterin preparations with enhanced acrolein concentration of 12.1 mM and higher were effective to reduce plate counts ofEnterobacteriaceae and yeasts and molds washed lettuce until day 7 but induced pronounced discoloration of lettuce. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
6. Reuterin Demonstrates Potent Antimicrobial Activity Against a Broad Panel of Human and Poultry Meat Campylobacter spp. Isolates.
- Author
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Asare, Paul Tetteh, Zurfluh, Katrin, Greppi, Anna, Lynch, Denise, Schwab, Clarissa, Stephan, Roger, and Lacroix, Christophe
- Subjects
CAMPYLOBACTER ,CAMPYLOBACTER coli ,CAMPYLOBACTER jejuni ,LACTOBACILLUS reuteri ,ANAEROBIC metabolism ,FOOD fermentation - Abstract
Reuterin is a broad-spectrum antimicrobial system produced by specific strains of Lactobacillus reuteri during anaerobic metabolism of glycerol. Acrolein is the main component responsible for its antimicrobial activity. Here, the sensitivity of Campylobacter jejuni (n = 51) and Campylobacter coli (n = 20) isolates from chicken meat and human stool samples to reuterin was investigated. The minimum inhibitory concentration (MIC) of C. jejuni and C. coli strains was measured between 1.5 and 3.0 µM of acrolein, below the MIC of the sensitive indicator strain Escherichia coli K12 (16.5 µM acrolein). The interaction of C. jejuni N16-1419 and the reuterin-producing L. reuteri PTA5_F13 was studied during 24 h co-cultures with or without glycerol. A high C. jejuni growth was observed in cultures without glycerol. In contrast, C. jejuni growth decreased from 7.3 ± 0.1 log CFU/mL to below detection limit (1 log CFU/mL) during co-cultures added with 28 mM glycerol. This bactericidal effect could be attributed to in situ reuterin production. The low MIC observed and the high sensitivity towards in situ produced reuterin suggests L. reuteri combined with glycerol, as a possible intervention option to reduce Campylobacter in the food chain. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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