Clinical efficacy of probiotics in prevention of infectious diseases among hospitalized patients in ICU and non‐ICU wards in clinical randomized trials: A systematic review

BACKGROUND AND AIMS: The present study aimed to review probiotics' clinical efficacy in preventing infectious diseases among hospitalized patients in ICU and non‐ICU wards. METHODS: A search of Medline, EMBASE, The Cochrane Library, Science Direct, Open Grey, and Google Scholar was conducted for eligible publications from 2002 to 2020 following the requirements outlined in the PRISMA guideline. The search strategy was based on the combination of the following terms: “probiotics,” “prebiotics,” “synbiotics,” and “cross‐infection.” The logical operators “AND” (or the equivalent operator for the databases) and “OR” (e.g., probiotics OR prebiotics OR synbiotics) were used. RESULTS: The results indicated that the probiotic consumption caused a significant reduction in antibiotic‐associated diarrhea (AAD) and Clostridioides difficile infection (CDI) in 2/8 randomized clinical trials (RCTs) investigating AAD/CDI. Also, 5/12 clinical trials highlighted the considerable effects of probiotics on the reduction or prevention of ventilator associated pneumoniae (VAP), so the mean prevalence of VAP was lower in the probiotic group than in the placebo group. The total rate of nosocomial infections among preterm infants was nonsignificantly higher in the probiotic group compared to the control group. CONCLUSION: This systematic review shows that the administration of probiotics has moderate preventive or mitigating effects on the occurrence of VAP in ICU patients, CDI, AAD, and nosocomial infections among children. Consequently, applying antibiotics along with the proper probiotic species can be advantageous.