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Synergistic effects of Bifidobacterium thermophilum RBL67 and selected prebiotics on inhibition of Salmonella colonization in the swine proximal colon PolyFermS model.

Tanner SA, Chassard C, Zihler Berner A, Lacroix C - Gut Pathog (2014)

Bottom Line: Our study demonstrates the suitability of the porcine PolyFermS in vitro model to study nutritional effects of pro- and prebiotics on gut microbiota composition and activity.The inhibition effects of FOS and GOS on N-15 colonization are partly due to an increased acetate production, while further antimicrobial mechanisms may contribute to an enhanced inhibition with prebiotic-RBL67 combinations.A future direction of this work could be to understand the anti-Salmonella effects of Bifidobacterium thermophilum RBL67 in the presence of prebiotics to unravel the mechanism of this probiotic:pathogen interaction.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland.

ABSTRACT

Background: Probiotics and prebiotics are promising strategies to counteract Salmonella prevalence in swine. In the present study, we investigated the effects of prebiotics (fructo- (FOS), galacto- (GOS) and mannan- (MOS) oligosaccharides) and the bacteriocinogenic Bifidobacterium thermophilum RBL67 (RBL67) on Salmonella enterica subsp. enterica serovar Typhimurium N-15 (N-15) colonization using the PolyFermS in vitro continuous fermentation model simulating the swine proximal colon.

Material and methods: The PolyFermS model was designed with a first-stage reactor containing immobilized fecal pig microbiota. This reactor continuously inoculated five parallel second-stage reactors, a control and four treatment reactors, all operated with proximal colon conditions. FOS and GOS (5.2 g/day), and MOS (half dosage) and RBL67 (10(8) copy numbers/mL applied daily) were tested on the ability of N-15 to colonize reactors, inoculated with the same microbiota. Reactor effluents were collected daily and analyzed for microbial composition (quantitative PCR and 454 pyrosequencing of 16S rRNA gene pool) and main metabolites (HPLC).

Results: RBL67 and N-15 were shown to stably colonize the system. Colonization of N-15 was strongly inhibited by FOS and GOS, whereas addition of RBL67 alone or combined with MOS showed intermediate results. However, the effect of FOS and GOS was enhanced when prebiotics were combined with a daily addition of RBL67. FOS and GOS increased the total short chain fatty acid production, especially acetate and propionate. RBL67 combined with FOS additionally stimulated butyrate production.

Conclusions: Our study demonstrates the suitability of the porcine PolyFermS in vitro model to study nutritional effects of pro- and prebiotics on gut microbiota composition and activity. It can further be used to monitor Salmonella colonization. The inhibition effects of FOS and GOS on N-15 colonization are partly due to an increased acetate production, while further antimicrobial mechanisms may contribute to an enhanced inhibition with prebiotic-RBL67 combinations. A future direction of this work could be to understand the anti-Salmonella effects of Bifidobacterium thermophilum RBL67 in the presence of prebiotics to unravel the mechanism of this probiotic:pathogen interaction.

No MeSH data available.


Salmonellacell counts determined in test reactors during treatment periods 2–4. Treatment periods 2–4 were used to test the effect of prebiotics (FOS, GOS) or RBL67 or combinations of RBL67 with FOS, GOS or MOS on Salmonella N-15 colonization. RBL67 and/or prebiotics were added to TRs at 108 CN/mL and 5.2 g/day, respectively during a 2 days prevention period and for 5 days after N-15 challenge. N-15 was inoculated once at 106 cfu/mL and was monitored by plate counts on CHROMAgar™ Salmonella. (─) Salmonella detection limit of 4.1 cfu/mL. Cell counts at day 0 correspond to the inoculum added to the reactors.
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Fig3: Salmonellacell counts determined in test reactors during treatment periods 2–4. Treatment periods 2–4 were used to test the effect of prebiotics (FOS, GOS) or RBL67 or combinations of RBL67 with FOS, GOS or MOS on Salmonella N-15 colonization. RBL67 and/or prebiotics were added to TRs at 108 CN/mL and 5.2 g/day, respectively during a 2 days prevention period and for 5 days after N-15 challenge. N-15 was inoculated once at 106 cfu/mL and was monitored by plate counts on CHROMAgar™ Salmonella. (─) Salmonella detection limit of 4.1 cfu/mL. Cell counts at day 0 correspond to the inoculum added to the reactors.

Mentions: Pretreatments with RBL67 and prebiotics were tested during periods 2–4 on N-15. After N-15 infection in period 2, N-15 cell counts declined 1.6 log10 cfu/mL during the first 2 days and stabilized at 5.0 ± 0.2 log10 cfu/mL effluent (days 2–5) (Figure 3). Unexpectedly, N-15 cell counts in the following periods showed either a limited initial decline phase after the first day of challenge followed by stability (6.3 ± 0.1 log10 cfu/mL, period 3, days 1–5), or a steady increase until day 2 to reach 7.4 ± 0.1 log10 cfu/mL (period 4, days 2–5). The treatments with FOS and GOS during periods 2 and 3 induced a strong inhibition of N-15 colonization, with N-15 cell numbers decreasing below the detection limit (4.1 log10 cfu/mL effluent) 3 days post-infection. When FOS or GOS were combined with RBL67 (R-FOS and R-GOS) during periods 2–4, N-15 counts decreased even more rapidly compared to treatments with the prebiotics alone, reaching non-detectable levels after two days post-infection (periods 2 and 3) or reducing initial N-15 counts by approximately 2 log10 cfu/mL (period 4). Intermediate effects were recorded for RBL67 alone (periods 2 and 3) and in combination with MOS (R-MOS, period 4), with a reduction of N-15 counts 2 days post-infection by approximately 1.8 ± 0.3 and 0.7 log10 cfu/mL, respectively.Figure 3


Synergistic effects of Bifidobacterium thermophilum RBL67 and selected prebiotics on inhibition of Salmonella colonization in the swine proximal colon PolyFermS model.

Tanner SA, Chassard C, Zihler Berner A, Lacroix C - Gut Pathog (2014)

Salmonellacell counts determined in test reactors during treatment periods 2–4. Treatment periods 2–4 were used to test the effect of prebiotics (FOS, GOS) or RBL67 or combinations of RBL67 with FOS, GOS or MOS on Salmonella N-15 colonization. RBL67 and/or prebiotics were added to TRs at 108 CN/mL and 5.2 g/day, respectively during a 2 days prevention period and for 5 days after N-15 challenge. N-15 was inoculated once at 106 cfu/mL and was monitored by plate counts on CHROMAgar™ Salmonella. (─) Salmonella detection limit of 4.1 cfu/mL. Cell counts at day 0 correspond to the inoculum added to the reactors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4215022&req=5

Fig3: Salmonellacell counts determined in test reactors during treatment periods 2–4. Treatment periods 2–4 were used to test the effect of prebiotics (FOS, GOS) or RBL67 or combinations of RBL67 with FOS, GOS or MOS on Salmonella N-15 colonization. RBL67 and/or prebiotics were added to TRs at 108 CN/mL and 5.2 g/day, respectively during a 2 days prevention period and for 5 days after N-15 challenge. N-15 was inoculated once at 106 cfu/mL and was monitored by plate counts on CHROMAgar™ Salmonella. (─) Salmonella detection limit of 4.1 cfu/mL. Cell counts at day 0 correspond to the inoculum added to the reactors.
Mentions: Pretreatments with RBL67 and prebiotics were tested during periods 2–4 on N-15. After N-15 infection in period 2, N-15 cell counts declined 1.6 log10 cfu/mL during the first 2 days and stabilized at 5.0 ± 0.2 log10 cfu/mL effluent (days 2–5) (Figure 3). Unexpectedly, N-15 cell counts in the following periods showed either a limited initial decline phase after the first day of challenge followed by stability (6.3 ± 0.1 log10 cfu/mL, period 3, days 1–5), or a steady increase until day 2 to reach 7.4 ± 0.1 log10 cfu/mL (period 4, days 2–5). The treatments with FOS and GOS during periods 2 and 3 induced a strong inhibition of N-15 colonization, with N-15 cell numbers decreasing below the detection limit (4.1 log10 cfu/mL effluent) 3 days post-infection. When FOS or GOS were combined with RBL67 (R-FOS and R-GOS) during periods 2–4, N-15 counts decreased even more rapidly compared to treatments with the prebiotics alone, reaching non-detectable levels after two days post-infection (periods 2 and 3) or reducing initial N-15 counts by approximately 2 log10 cfu/mL (period 4). Intermediate effects were recorded for RBL67 alone (periods 2 and 3) and in combination with MOS (R-MOS, period 4), with a reduction of N-15 counts 2 days post-infection by approximately 1.8 ± 0.3 and 0.7 log10 cfu/mL, respectively.Figure 3

Bottom Line: Our study demonstrates the suitability of the porcine PolyFermS in vitro model to study nutritional effects of pro- and prebiotics on gut microbiota composition and activity.The inhibition effects of FOS and GOS on N-15 colonization are partly due to an increased acetate production, while further antimicrobial mechanisms may contribute to an enhanced inhibition with prebiotic-RBL67 combinations.A future direction of this work could be to understand the anti-Salmonella effects of Bifidobacterium thermophilum RBL67 in the presence of prebiotics to unravel the mechanism of this probiotic:pathogen interaction.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland.

ABSTRACT

Background: Probiotics and prebiotics are promising strategies to counteract Salmonella prevalence in swine. In the present study, we investigated the effects of prebiotics (fructo- (FOS), galacto- (GOS) and mannan- (MOS) oligosaccharides) and the bacteriocinogenic Bifidobacterium thermophilum RBL67 (RBL67) on Salmonella enterica subsp. enterica serovar Typhimurium N-15 (N-15) colonization using the PolyFermS in vitro continuous fermentation model simulating the swine proximal colon.

Material and methods: The PolyFermS model was designed with a first-stage reactor containing immobilized fecal pig microbiota. This reactor continuously inoculated five parallel second-stage reactors, a control and four treatment reactors, all operated with proximal colon conditions. FOS and GOS (5.2 g/day), and MOS (half dosage) and RBL67 (10(8) copy numbers/mL applied daily) were tested on the ability of N-15 to colonize reactors, inoculated with the same microbiota. Reactor effluents were collected daily and analyzed for microbial composition (quantitative PCR and 454 pyrosequencing of 16S rRNA gene pool) and main metabolites (HPLC).

Results: RBL67 and N-15 were shown to stably colonize the system. Colonization of N-15 was strongly inhibited by FOS and GOS, whereas addition of RBL67 alone or combined with MOS showed intermediate results. However, the effect of FOS and GOS was enhanced when prebiotics were combined with a daily addition of RBL67. FOS and GOS increased the total short chain fatty acid production, especially acetate and propionate. RBL67 combined with FOS additionally stimulated butyrate production.

Conclusions: Our study demonstrates the suitability of the porcine PolyFermS in vitro model to study nutritional effects of pro- and prebiotics on gut microbiota composition and activity. It can further be used to monitor Salmonella colonization. The inhibition effects of FOS and GOS on N-15 colonization are partly due to an increased acetate production, while further antimicrobial mechanisms may contribute to an enhanced inhibition with prebiotic-RBL67 combinations. A future direction of this work could be to understand the anti-Salmonella effects of Bifidobacterium thermophilum RBL67 in the presence of prebiotics to unravel the mechanism of this probiotic:pathogen interaction.

No MeSH data available.