Colonization of preterm gnotobiotic piglets with probiotic Lactobacillus rhamnosus GG and its interference with Salmonella Typhimurium.

SALMONELLA typhimurium; LACTOBACILLUS rhamnosus; PIGLETS; PREMATURE infants; COLONIZATION

Summary: A balanced microbiota of the gastrointestinal tract (GIT) is a prerequisite for a healthy host. The GIT microbiota in preterm infants is determined by the method of delivery and nutrition. Probiotics can improve the GIT microbiota balance and suitable animal models are required to verify their harmlessness. Preterm gnotobiotic piglets were colonized with Lactobacillus rhamnosus GG (LGG) to evaluate its safety and possible protective action against infection with an enteric pathogen, Salmonella Typhimurium (ST). Clinical signs (anorexia, somnolence, fever and diarrhea), bacterial interference and translocation, intestinal histopathology, transcriptions of claudin‐1, occludin and interferon (IFN)‐γ, intestinal and systemic protein levels of interleukin (IL)‐8, IL‐12/23 p40 and IFN‐γ were compared among (i) germ‐free, (ii) LGG‐colonized, (iii) ST‐infected and (iv) LGG‐colonized and subsequently ST‐infected piglets for 24 h. Both LGG and ST‐colonized the GIT; LGG translocated in some cases into mesenteric lymph nodes and the spleen but did not cause bacteremia and clinical changes. ST caused clinical signs of gastroenteritis, translocated into mesenteric lymph nodes, the spleen, liver and blood, increased claudin‐1 and IFN‐γ transcriptions, but decreased occludin transcription and increased local and systemic levels of IL‐8 and IL‐12/23 p40. Previous colonization with LGG reduced ST colonization in the jejunum and translocation into the liver, spleen and blood. It partially ameliorated histopathological changes in the intestine, reduced IL‐8 levels in the jejunum and plasma and IL‐12/23 p40 in the jejunum. The preterm gnotobiotic piglet model of the vulnerable preterm immunocompromised infant is useful to verify the safety of probiotics and evaluate their protective effect. We evaluated the effect of the previous colonization of the hysterectomy‐derived preterm gnotobiotic piglets with Lactobacillus rhamnosus GG against subsequent infection with Salmonella Typhimurium. This colonization with LGG partially ameliorated the deleterious effect of infection with S. Typhimurium, as it was evaluated by CFU enumeration, intestinal histology and the local and systemic values of IL‐8 and IL‐12/23 p40. It is the first use of preterm gnotobiotic piglets as an infectious model of vulnerable immunocompromised preterm infants to verify probiotic safety and its bacterial interference with an enteric pathogen. [ABSTRACT FROM AUTHOR]

Copyright of Clinical & Experimental Immunology is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)