Lactobacillus acidophilus W55 (L. acidophilus W55)

Lactobacillus acidophilus W55 is a specific probiotic strain of the Gram-positive bacterium Lactobacillus acidophilus, widely recognized for its role in maintaining gastrointestinal and immune homeostasis [1, 3]. As a member of the lactic acid bacteria group, it survives the harsh conditions of the stomach and bile to colonize the intestinal mucosa, where it inhibits the growth of pathogens through competitive exclusion and the production of antimicrobial substances like bacteriocins and organic acids [1, 10, 18]. W55 is frequently included in multi-strain probiotic formulations designed to prevent antibiotic-associated diarrhea and manage functional gastrointestinal disorders such as irritable bowel syndrome [5, 7, 15]. Beyond local gut effects, it demonstrates significant immunomodulatory capacity by influencing the balance of regulatory T cells and pro-inflammatory cytokines, which has implications for systemic health, including bone density and allergic responses [4, 11, 16]. The strain also supports the integrity of the intestinal barrier by regulating tight junction proteins and modulating host signaling pathways [11, 15]. While generally considered safe for the general population, its administration in critically ill or immunocompromised patients carries a risk of opportunistic infection and requires clinical oversight [14, 15, 19].

Other names

L. acidophilus W55Lactobacillus acidophilus strain W55

Competitive exclusion of pathogens, production of antimicrobial metabolites (e.g., lactic acid, bacteriocins), and modulation of host immune signaling pathways.