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Updated: May 10, 2026
Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat
Published on: October 29, 2014
Bifidobacterial supplementation reduces the incidence of necrotizing enterocolitis in a neonatal rat model
M S Caplan1, R Miller-Catchpole, S Kaup
1Department of Pediatrics, Northwestern University Medical School, Evanston Hospital, Evanston, Illinois, USA.
Insights
Supplementing newborn rats with Bifidobacterium infantis led to intestinal colonization and significantly reduced the incidence of necrotizing enterocolitis (NEC). This suggests bifidobacteria can protect against NEC development in vulnerable infants.
Area of Science:
- Neonatal medicine
- Gastroenterology
- Microbiology
Background:
- Neonatal necrotizing enterocolitis (NEC) is a severe intestinal disease affecting premature infants.
- Intestinal bacterial overgrowth is a contributing factor to NEC pathogenesis.
- Bifidobacteria are beneficial bacteria that may confer protection against intestinal disorders.
Purpose of the Study:
- To investigate if exogenous Bifidobacterium infantis supplementation colonizes the neonatal rat gut.
- To determine if Bifidobacterium infantis supplementation reduces the incidence of experimentally induced NEC in newborn rats.
Main Methods:
- Newborn rat pups received daily oral doses of Bifidobacterium infantis, Escherichia coli, or saline.
- Animals were subjected to a protocol simulating NEC conditions, including formula feeding and asphyxia/cold stress.
- Outcomes assessed included NEC incidence, plasma endotoxin levels, and intestinal phospholipase A2 expression.
Main Results:
- Bifidobacterium infantis successfully colonized the intestines within 24 hours and was detected in stool by 48 hours.
- Bifidobacteria supplementation significantly decreased the NEC incidence compared to control and E. coli groups (P < 0.01).
- Lower plasma endotoxin and intestinal phospholipase A2 levels were observed in bifidobacteria-treated pups, indicating reduced bacterial translocation and inflammation.
Conclusions:
- Intestinal colonization with Bifidobacterium infantis effectively reduces the risk and incidence of necrotizing enterocolitis in a neonatal rat model.
- These findings support the potential therapeutic role of bifidobacteria in preventing NEC in premature infants.
Background & Aims:
Neonatal necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease of premature infants partly caused by intestinal bacterial proliferation. Because bifidobacteria are thought to reduce the risk for intestinal disturbances associated with pathogenic bacterial colonization, we hypothesized that exogenous bifidobacterial supplementation to newborn rats would result in intestinal colonization and a reduction in the incidence of neonatal NEC.
Methods:
Newborn rat pups were given Bifidobacterium infantis (10(9) organisms per animal daily), Escherichia coli, or saline control and exposed to the NEC protocol consisting of formula feeding (Esbilac; 200 cal. kg(-1). day(-1)) and asphyxia (100% N(2) for 50 seconds followed by cold exposure for 10 minutes). Outcome measures included stool and intestinal microbiological evaluation, gross and histological evidence of NEC, plasma endotoxin concentration, intestinal phospholipase A(2) expression, and estimation of intestinal mucosal permeability.
Results:
Bifidobacterial supplementation resulted in intestinal colonization by 24 hours and appearance in stool samples by 48 hours. Bifidobacteria-supplemented animals had a significant reduction in the incidence of NEC compared with controls and E. coli-treated animals (NEC, 7/24 B. infantis vs. 19/27 control vs. 16/23 E. coli; P < 0.01). Plasma endotoxin and intestinal phospholipase A(2) expression were lower in bifidobacteria-treated pups than in controls, supporting the role of bacterial translocation and activation of the inflammatory cascade in the pathophysiology of NEC.
Conclusions:
Intestinal bifidobacterial colonization reduces the risk of NEC in newborn rats.
