Aims: Mucosal surfaces of newborns are colonized by microbes in dependence on their delivery and nutrition. Are probiotics safety to Caesarean section derived immunocompromised preterm infants?

Methods: Hysterectomy derived preterm germ-free piglets, either treated or non-treated with serum, were colonized with Lactobacillus rhamnosus (LGG) four hours after hysterectomy. Bacterial translocation of LGG, its protection against subsequent infection of the piglets with Salmonella Typhimurium, and induction of plasma and intestinal levels of inflammatory cytokines IL‑1 beta, IL-6, IL-8, IL-10, IFN-gamma, TNF-alpha (xMAP), and HMGB1 (ELISA) were estimated.

Results: LGG did not translocate in one week old preterm piglets. It was found in mesenteric lymph nodes in piglets subsequently infected with S. Typhimurium only but it did not translocate to other organs (blood, liver, spleen, and lungs). Inflammatory cytokine values were not induced by LGG alone but they were dramatically increased in piglets infected with Salmonella. The piglets treated with mixed serum of adult sows showed reduced levels of inflammatory cytokines as in the intestine so in plasma.

Conclusions: It is necessary to develop highly sensitive animal models to evaluate a safety of different probiotics for immunocompromised preterm infants. A high attention should be paid to a selection of suitable markers to evaluate possible risk of these probiotics. Inflammatory cytokines in the intestine/feces of preterm newborns should be a suitable candidates of such markers. 

Acknowledgements: This work was supported by grants 13-14736S of the Czech Science Foundation, FR-TI4/504 of the Ministry of Industry and Trade of the Czech Republic and the Institutional Research Concept RVO: 61388971 of the Institute of Microbiology.