This study aims to evaluate the efficacy and safety of the probiotic Bifidobacterium breve PRL2020 in preventing gastrointestinal and extra-intestinal side effects caused by Amoxicillin or Amoxicillin/Clavulanic Acid in pediatric patients. The study will compare a treatment group receiving the probiotic alongside antibiotics with a control group receiving antibiotics alone. The primary focus is on reducing antibiotic-induced intestinal discomfort through microbiota modulation.

Antibiotic therapy, particularly with Amoxicillin and Amoxicillin/Clavulanic Acid, is widely used to treat bacterial infections in children. However, these antibiotics often disrupt the gut microbiota, leading to gastrointestinal side effects such as diarrhea, bloating, abdominal pain, and constipation. This imbalance can reduce the abundance of beneficial bacterial species, including bifidobacteria, potentially leading to long-term gastrointestinal dysbiosis.

This observational, non-profit study aims to evaluate the efficacy and safety of Bifidobacterium breve PRL2020 (Brevicillin®), a probiotic strain with demonstrated resistance to Amoxicillin and Amoxicillin/Clavulanic Acid. Prior research has shown that this strain has a high minimum inhibitory concentration (MIC) of 32-64 μg/mL, making it a promising candidate for preventing antibiotic-associated gut microbiota alterations.

The study will recruit 800 pediatric patients (ages 3-12 years) who require antibiotic therapy for infections. Participants will be randomized into two groups:

Probiotic Group: Receives Bifidobacterium breve PRL2020 (20 billion CFU per day) alongside antibiotic treatment.

Control Group: Receives antibiotics only, without probiotic supplementation. The primary outcome will be the evaluation of gastrointestinal symptoms and stool consistency using the Bristol Stool Scale and a VAS symptom scale (0-7 points) over a 15-day period (treatment duration + follow-up). The secondary outcome will assess the safety and tolerability of the probiotic intervention.

Clinical data will be collected via a daily symptom diary maintained by caregivers, including frequency of bowel movements, stool quality, presence of abdominal pain, and other potential side effects. Statistical analysis will determine whether Bifidobacterium breve PRL2020 significantly reduces antibiotic-associated gastrointestinal disturbances compared to the control group.

This study is expected to provide critical insights into the role of probiotic supplementation in mitigating antibiotic-induced dysbiosis, potentially shaping future guidelines for pediatric antibiotic therapy.

Inclusion Criteria:

• Age 3 to 12 years
• Requiring antibiotic therapy with Amoxicillin or Amoxicillin/Clavulanic Acid
• Ability to comply with the study protocol (parents/caregivers must complete symptom diaries)

Exclusion Criteria:

• Use of any antibiotic therapy within 3 months before study enrollment
• Known gastrointestinal diseases (e.g., inflammatory bowel disease, celiac disease)
• History of chronic diarrhea or constipation
• Allergy to probiotics or study interventions
• Any immunocompromised state