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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

Improved clinical efficacy. Probiotic dosing of BALB/c mice with Bifidobacterium breve bilE+ (black) reduces the level of subsequent Listeria monocytogenes infection. Bacterial growth was followed in (A) the liver and (B) the spleen 3 days post infection.
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Figure 6: Improved clinical efficacy. Probiotic dosing of BALB/c mice with Bifidobacterium breve bilE+ (black) reduces the level of subsequent Listeria monocytogenes infection. Bacterial growth was followed in (A) the liver and (B) the spleen 3 days post infection.

Mentions: Administration of B. breve UCC2003 has previously been demonstrated to reduce splenic levels of L. monocytogenes following oral infection of mice [23]. We hypothesized that the elevated colonisation of B. breve BilE+ in the small intestines of mice (Fig. 5) may further enhance this protective effect since L. monocytogenes invades at this site. To test this hypothesis we administered mice with either wild-type or BilE+ B. breve UCC2003 on three consecutive days and challenged with oral L. monocytogenes infection at day 14 post-inoculation. At the 14 day time point we again detected higher levels of the engineered BilE+ strain relative to the wild-type in mouse faeces (data not shown). Following oral infection with L. monocytogenes we determined that oral dosing with the engineered BilE+ B. breve strain significantly enhanced clearance of L. monocytogenes as assessed by pathogen load in the liver (Fig. 6A). A similar (though not statistically significant) trend was seen when the numbers of Listeria in the spleens of the infected mice was determined (Fig. 6B). Although differences in infectious burden were small the data indicate improved probiotic efficacy of engineered B. breve.


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)

Improved clinical efficacy. Probiotic dosing of BALB/c mice with Bifidobacterium breve bilE+ (black) reduces the level of subsequent Listeria monocytogenes infection. Bacterial growth was followed in (A) the liver and (B) the spleen 3 days post infection.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: Improved clinical efficacy. Probiotic dosing of BALB/c mice with Bifidobacterium breve bilE+ (black) reduces the level of subsequent Listeria monocytogenes infection. Bacterial growth was followed in (A) the liver and (B) the spleen 3 days post infection.
Mentions: Administration of B. breve UCC2003 has previously been demonstrated to reduce splenic levels of L. monocytogenes following oral infection of mice [23]. We hypothesized that the elevated colonisation of B. breve BilE+ in the small intestines of mice (Fig. 5) may further enhance this protective effect since L. monocytogenes invades at this site. To test this hypothesis we administered mice with either wild-type or BilE+ B. breve UCC2003 on three consecutive days and challenged with oral L. monocytogenes infection at day 14 post-inoculation. At the 14 day time point we again detected higher levels of the engineered BilE+ strain relative to the wild-type in mouse faeces (data not shown). Following oral infection with L. monocytogenes we determined that oral dosing with the engineered BilE+ B. breve strain significantly enhanced clearance of L. monocytogenes as assessed by pathogen load in the liver (Fig. 6A). A similar (though not statistically significant) trend was seen when the numbers of Listeria in the spleens of the infected mice was determined (Fig. 6B). Although differences in infectious burden were small the data indicate improved probiotic efficacy of engineered B. breve.

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