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


CONCLUSIONS
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.
Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland. watson_d@hotmail.com
Debbie
D
Watson
Roy D
RD
Sleator
Colin
C
Hill
Cormac G M
CG
Gahan
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000818:Animals; D000898:Antibiosis; D001426:Bacterial Proteins / Q000235:genetics; D001644:Bifidobacterium / Q000235:genetics / Q000502:physiology*; D001646:Bile / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D018274:Electroporation; D005243:Feces / Q000382:microbiology; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D005772:Gastrointestinal Transit; D013294:Lactococcus lactis / Q000235:genetics / Q000502:physiology*; D008089:Listeria monocytogenes / Q000235:genetics; D008088:Listeriosis / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D050296:Microbial Viability; D030781:Organisms, Genetically Modified / Q000235:genetics / Q000382:microbiology; D010957:Plasmids; D019936:Probiotics / Q000008:administration & dosage*; D014169:Transformation, Bacterial
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; C500455:BilE protein, Listeria monocytogenes; D004269:DNA, Bacterial