ABSTRACT
BACKGROUND AND OBJECTIVES: Newborns, particularly premature ones, are vulnerable to bacterial infections and often receive antibiotics, disrupting their normal intestinal microbiota. Probiotics have multiple health benefits and are recommended for restoring balance, but caution is needed due to potential consequences, such as promoting antibiotic resistance. Therefore, this study aimed to conduct a systematic review to assess current knowledge regarding the impact of probiotics on antibiotic resistance in newborns. METHODS: This systematic review is aligned with the PRISMA 2020 statement. The search involved three electronic databases (PubMed, Scopus, and Web of Science) and the keywords used were "newborn", "probiotic", and "antibiotic resistance". Titles/abstracts were independently analyzed, followed by full-text assessments. Data extraction and synthesis were conducted, assessing outcomes like antibiotic resistance gene and mobile gene elements quantity and quality, vancomycin resistant enterococci colonization, antibiotic-resistant bacteria colonization, and microbiota changes. It was only included randomized controlled trials and cohort studies focusing on human newborns. RESULTS: In the study selection process, 1,970 articles were identified and six were included in this review. The results varied, with two studies suggesting a positive impact of probiotics on antibiotic resistance, one a negative impact, while three others found no significant impact. Microbiota changes were also addressed across four studies, where the findings included promotion of beneficial bacteria and reduction of potential pathogens. Bias risk was evaluated using Joanna Briggs Institute tools. CONCLUSION: Our findings did not allow for clear conclusions to be drawn, due to the observed heterogeneity between studies, highlighting the need for further studies.