Abstract
OBJECTIVE: The study objective was to investigate the effect of mixed probiotics on the diversity of the pulmonary flora in critically ill patients requiring mechanical ventilation by analysing the changes in lung microbes. METHODS: 24 adult critically ill patients who needed mechanical ventilation in our hospital were randomly divided into a probiotic group and a control group. Then, the probiotic group was given Live Combined Bifidobacterium, Lactobacillus and Enterococcus Capsules, Oral (Bifico) by nasal feeding within 24 h after mechanical ventilation. Bronchoalveolar lavage fluid (BALF) and venous blood were collected within 24 h after mechanical ventilation and on the 5th day after mechanical ventilation, and the treatment status of patients (mechanical ventilation time, 28-day survival), measured cytokine levels (IL-1 β, IL-6, IL-8, IL-17A) and changes in pulmonary microorganisms were observed. RESULTS: The microbial diversity of BALF samples decreased in the control group, and there was no significant difference in the probiotic group. Species difference analysis showed that among the three probiotics (Bifidobacterium, Lactobacillus, Enterococcus) used for intervention, Lactobacillus caused significant differences in BALF in the control group. Clinical factor association analysis displayed significant associations with IL-17A levels in both blood and BALF. CONCLUSION: Mechanical ventilation can cause a decline in pulmonary microbial diversity, which can be improved by administering mixed probiotics.