Role of Bifidobacterium breve PRL2020 in reducing symptoms of antibiotic-associated diarrhea in children

Background Antibiotic-associated diarrhea (AAD) is a common adverse effect of amoxicillin and amoxicillin/clavulanate therapy in children, primarily driven by antibiotic-induced dysbiosis, altered fermentation, and reduced production of short-chain fatty acids. Probiotics may help prevent AAD, but many strains are inhibited by these antibiotics. The present study specifically addresses the clinical impact of a single probiotic strain, Bifidobacterium breve PRL2020, rather than the intestinal microbiota as a whole. Methods We conducted a 15-day, prospective, single-center controlled study enrolling children between January 2021 and December 2022, recruited by three Italian pediatricians from the Lombardy region (Northern Italy), to evaluate the efficacy of Bifidobacterium breve PRL2020, a strain with documented resistance to amoxicillin and amoxicillin/clavulanate, in children aged 4–12 years undergoing antibiotic therapy. Parents recorded daily bowel movements, episodes of diarrhea, abdominal pain (VAS), and stool consistency (Bristol scale). Results Among 426 enrolled children (284 supplemented, 142 controls), supplementation with B. breve PRL2020 significantly reduced the number of diarrheal episodes ( p < 0.001) and abdominal pain ( p < 0.005) compared with controls, without affecting stool frequency or consistency. Some children experienced mild diarrheal events (<3 episodes/day) not meeting the formal definition of AAD but likely reflecting partial manifestations of AAD-related mechanisms. Conclusions B. breve PRL2020 was associated with a significant reduction in antibiotic-associated diarrhea and abdominal discomfort in children receiving amoxicillin or amoxicillin/clavulanate. Its antibiotic resistance profile supports its use as a precision probiotic. Accordingly, the observed effects should be interpreted as strain-specific outcomes attributable to PRL2020 supplementation, and not as evidence of a global microbiota-wide modification. Longer-term, multi-omics studies are needed to confirm durability of the effect and to investigate combined probiotic–prebiotic strategies for optimizing gut microbiota resilience.