Lactobacillus reuteri ATCC 55730

Lactobacillus reuteri ATCC 55730 is a specific probiotic strain that produces reuterin (3-hydroxypropionaldehyde), a broad-spectrum antimicrobial compound, along with short-chain fatty acids and bacteriocins that modulate gut microbiota composition. Its primary mechanism involves competitive exclusion of pathogens, enhancement of intestinal barrier integrity via tight junction proteins, and immunomodulation through dendritic cell signaling.

Origin & History

Lactobacillus reuteri ATCC 55730 is a probiotic bacterium strain naturally found in the human gastrointestinal tract, particularly colonizing the stomach, duodenum, and ileum. It is commercially produced and delivered in tablet and powder formulations as a dietary supplement containing standardized amounts of viable bacterial cells measured in CFU (colony-forming units).

Historical & Cultural Context

The research provided does not contain information about traditional or historical use of L. reuteri ATCC 55730. This strain represents a modern clinical probiotic application developed through contemporary microbiological research rather than traditional medicine.

Health Benefits

• Reduces antibiotic-associated diarrhea in hospitalized adults (moderate evidence from randomized controlled trials)
• Improves symptoms of mild to moderate ulcerative colitis in children, with significant reduction in Mayo scores from 8.6 to 3.2 (strong evidence from RCT with 40 participants)
• Establishes beneficial colonization in stomach and duodenum, increasing from 10-30% to 80-100% colonization rates (moderate evidence from clinical studies)
• Modulates intestinal immune response by increasing beneficial B-lymphocytes and CD4+ T-cells while reducing inflammatory histiocytes (moderate evidence from immunological studies)
• Demonstrates moderate effectiveness in treating acute gastroenteritis in children (moderate evidence, though strain later replaced due to antibiotic resistance concerns)

How It Works

L. reuteri ATCC 55730 produces reuterin (3-hydroxypropionaldehyde) from glycerol via the enzyme glycerol dehydratase, creating broad-spectrum antimicrobial activity against gram-positive and gram-negative pathogens. The strain also upregulates tight junction proteins including claudin-1 and occludin, reducing intestinal permeability and preventing bacterial translocation. Additionally, it modulates mucosal immunity by promoting regulatory T-cell differentiation through dendritic cell TLR2/TLR4 signaling and suppressing pro-inflammatory cytokines TNF-α and IL-6 while increasing anti-inflammatory IL-10.

Scientific Research

Clinical trials have examined L. reuteri ATCC 55730 in multiple conditions, including a prospective RCT in 40 children with ulcerative colitis showing significant improvement with rectal enema administration, and colonization studies in 19 volunteers demonstrating effective gastrointestinal establishment. Dosing studies have used 1-4 × 10⁸ CFU daily, with immunological assessments showing increased duodenal B-lymphocytes and ileal CD4+ T-cells.

Clinical Summary

A randomized controlled trial with 40 pediatric participants demonstrated strong evidence that L. reuteri ATCC 55730 significantly improves mild to moderate ulcerative colitis, reducing Mayo scores from 8.6 to 3.2 compared to placebo. Moderate evidence from multiple RCTs in hospitalized adults supports its efficacy in reducing the incidence and duration of antibiotic-associated diarrhea, with typical dosages of 1–2 × 10^8 CFU daily. Study populations have been limited in size, and most trials range from 4 to 12 weeks in duration, which constrains conclusions about long-term efficacy and safety. Evidence quality varies by indication, with pediatric IBD data being notably more robust than adult gastrointestinal outcomes.

Nutritional Profile

Lactobacillus reuteri ATCC 55730 is a probiotic microorganism, not a conventional food ingredient, so macronutrient and micronutrient contributions to diet are negligible at standard doses. Key bioactive compounds and characteristics include: (1) Reuterin (3-hydroxypropionaldehyde, 3-HPA) — a broad-spectrum antimicrobial compound produced during glycerol fermentation, active at concentrations of approximately 15–30 mM in vitro, inhibiting competing pathogens including Salmonella, Listeria, and Clostridium species. (2) Reutericyclin — a membrane-active antimicrobial tetramic acid derivative with activity against Gram-positive organisms. (3) Cobalamin (Vitamin B12) — L. reuteri ATCC 55730 is among documented B12-synthesizing lactobacilli; de novo biosynthesis occurs intracellularly, though contribution to host B12 status at probiotic doses (typically 1×10^8 to 1×10^11 CFU/day) is considered minor and not a primary nutritional source. (4) Short-chain fatty acids (SCFAs) — produces acetate and small quantities of propionate as fermentation end-products in the gut; precise luminal concentrations are host- and substrate-dependent. (5) Cell wall components include peptidoglycan and lipoteichoic acid, which act as ligands for host Toll-like receptors (TLR-2), contributing to immunomodulatory signaling rather than caloric intake. (6) Exopolysaccharides (EPS) — produced in strain-specific quantities; function as prebiotically active compounds and biofilm matrix components, with potential mucoadhesive properties supporting the observed colonization increase from 10–30% to 80–100% in gastric and duodenal mucosa. Standard commercial doses deliver 1×10^8 to 1×10^10 live CFU per serving; caloric contribution is essentially zero (<1 kcal per dose). No significant dietary fiber, fat, or protein content is delivered to the host at these doses.

Preparation & Dosage

Clinically studied dosages: Tablets containing 1-4 × 10⁸ CFU daily for 28 days for gastrointestinal colonization and antibiotic-associated diarrhea prevention. Rectal enema containing 10¹⁰ CFU for 8 weeks in ulcerative colitis. Chewable tablets with 10⁸ CFU for oral colonization. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Other Lactobacillus strains, Bifidobacterium species, Saccharomyces boulardii, Prebiotic fibers, Zinc carnosine

Safety & Interactions

L. reuteri ATCC 55730 is generally well tolerated at doses up to 1 × 10^9 CFU/day, with the most commonly reported side effects being mild bloating and flatulence during the initial 1–2 weeks of supplementation. Immunocompromised individuals, patients with central venous catheters, and those with short bowel syndrome face a small but documented risk of probiotic bacteremia and should use this strain only under medical supervision. Concurrent use with broad-spectrum antibiotics such as fluoroquinolones and tetracyclines may reduce strain viability; separating doses by at least 2 hours is advisable. Safety data in pregnancy and lactation are limited, and use during these periods should be discussed with a healthcare provider before initiation.