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Enhancing bile tolerance improves survival and persistence of Bifidobacterium and Lactococcus in the murine gastrointestinal tract.

Watson D, Sleator RD, Hill C, Gahan CG - BMC Microbiol. (2008)

Bottom Line: In vitro bile tolerance of both strains was significantly enhanced (P < 0.001), following heterologous expression of the Listeria monocytogenes bile resistance mechanism BilE.Strains harbouring bilE were also recovered at significantly higher levels (P < 0.001), than control strains from the faeces and intestines of mice (n = 5), following oral inoculation.Collectively the data indicates that bile tolerance can be enhanced in Bifidobacterium and Lactococcus species through rational genetic manipulation and that this can significantly improve delivery to and colonisation of the GI tract.

View Article: PubMed Central - HTML - PubMed

Affiliation: Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland. watson_d@hotmail.com

ABSTRACT

Background: The majority of commensal gastrointestinal bacteria used as probiotics are highly adapted to the specialised environment of the large bowel. However, unlike pathogenic bacteria; they are often inadequately equipped to endure the physicochemical stresses of gastrointestinal (GI) delivery in the host. Herein we outline a patho-biotechnology strategy to improve gastric delivery and host adaptation of a probiotic strain Bifidobacterium breve UCC2003 and the generally regarded as safe (GRAS) organism Lactococcus lactis NZ9000.

Results: In vitro bile tolerance of both strains was significantly enhanced (P < 0.001), following heterologous expression of the Listeria monocytogenes bile resistance mechanism BilE. Strains harbouring bilE were also recovered at significantly higher levels (P < 0.001), than control strains from the faeces and intestines of mice (n = 5), following oral inoculation. Furthermore, a B. breve strain expressing bilE demonstrated increased efficacy relative to the wild-type strain in reducing oral L. monocytogenes infection in mice.

Conclusion: Collectively the data indicates that bile tolerance can be enhanced in Bifidobacterium and Lactococcus species through rational genetic manipulation and that this can significantly improve delivery to and colonisation of the GI tract.

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Related in: MedlinePlus

Schematic of the design protocol.
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Figure 1: Schematic of the design protocol.

Mentions: Prior to commencement of the trials (outlined in Fig. 1), the absence of background microflora in murine faecal pellets was confirmed by plating onto the two selective agars containing antibiotic. For the study five mice were used per bacterial strain. Each mouse was administered 20 μL of bifidobacteria or lactococcus (2 × 109 CFU per mouse) by oral pipette for 3 consecutive days, leading to colonization of the gastrointestinal tract. Gastrointestinal persistence of both strains was tracked by measuring the excretion of viable B. breve in fresh faecal samples collected for 19 days post feeding and L. lactis for 3 days. Fresh samples were weighed, homogenized in PBS (Gibco, Paisley, Scotland), diluted and plated onto RCA or GM17 with the appropriate level of chloramphenicol. At days nineteen (B. breve) and four (L. lactis) post dosing the mice were sacrificed by cervical dislocation, intestines and caeca were excised. The organs were homoginized in 5 mls PBS, serially diluted and the bifidobacterial and lactococcal numbers in the intestines and caeca of dosed animals were determined by spread-plating homogenates onto RCACm4 and GM17Cm5 plates.


Enhancing bile tolerance improves survival and persistence of Bifidobacterium and Lactococcus in the murine gastrointestinal tract.

Watson D, Sleator RD, Hill C, Gahan CG - BMC Microbiol. (2008)

Schematic of the design protocol.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2577680&req=5

Figure 1: Schematic of the design protocol.
Mentions: Prior to commencement of the trials (outlined in Fig. 1), the absence of background microflora in murine faecal pellets was confirmed by plating onto the two selective agars containing antibiotic. For the study five mice were used per bacterial strain. Each mouse was administered 20 μL of bifidobacteria or lactococcus (2 × 109 CFU per mouse) by oral pipette for 3 consecutive days, leading to colonization of the gastrointestinal tract. Gastrointestinal persistence of both strains was tracked by measuring the excretion of viable B. breve in fresh faecal samples collected for 19 days post feeding and L. lactis for 3 days. Fresh samples were weighed, homogenized in PBS (Gibco, Paisley, Scotland), diluted and plated onto RCA or GM17 with the appropriate level of chloramphenicol. At days nineteen (B. breve) and four (L. lactis) post dosing the mice were sacrificed by cervical dislocation, intestines and caeca were excised. The organs were homoginized in 5 mls PBS, serially diluted and the bifidobacterial and lactococcal numbers in the intestines and caeca of dosed animals were determined by spread-plating homogenates onto RCACm4 and GM17Cm5 plates.

Bottom Line: In vitro bile tolerance of both strains was significantly enhanced (P < 0.001), following heterologous expression of the Listeria monocytogenes bile resistance mechanism BilE.Strains harbouring bilE were also recovered at significantly higher levels (P < 0.001), than control strains from the faeces and intestines of mice (n = 5), following oral inoculation.Collectively the data indicates that bile tolerance can be enhanced in Bifidobacterium and Lactococcus species through rational genetic manipulation and that this can significantly improve delivery to and colonisation of the GI tract.

View Article: PubMed Central - HTML - PubMed

Affiliation: Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland. watson_d@hotmail.com

ABSTRACT

Background: The majority of commensal gastrointestinal bacteria used as probiotics are highly adapted to the specialised environment of the large bowel. However, unlike pathogenic bacteria; they are often inadequately equipped to endure the physicochemical stresses of gastrointestinal (GI) delivery in the host. Herein we outline a patho-biotechnology strategy to improve gastric delivery and host adaptation of a probiotic strain Bifidobacterium breve UCC2003 and the generally regarded as safe (GRAS) organism Lactococcus lactis NZ9000.

Results: In vitro bile tolerance of both strains was significantly enhanced (P < 0.001), following heterologous expression of the Listeria monocytogenes bile resistance mechanism BilE. Strains harbouring bilE were also recovered at significantly higher levels (P < 0.001), than control strains from the faeces and intestines of mice (n = 5), following oral inoculation. Furthermore, a B. breve strain expressing bilE demonstrated increased efficacy relative to the wild-type strain in reducing oral L. monocytogenes infection in mice.

Conclusion: Collectively the data indicates that bile tolerance can be enhanced in Bifidobacterium and Lactococcus species through rational genetic manipulation and that this can significantly improve delivery to and colonisation of the GI tract.

Show MeSH
Related in: MedlinePlus