Difference analysis of intestinal flora in ICU patients with different sampling methods -a systematic Review and meta-analysis 

Background: ICU patients often use swab samples instead of stool samples for subsequent analysis due to the complexity of sampling. Whether there are significant differences in the gut microbiota between the two specimen types (stool and swab) has not been determined. We performed a meta-analysis to investigate whether gut microbiota obtained by different sampling methods were altered. Methods A systematic review of studies published in electronic databases up to December 2022 was performed. We included 11 studies that analyzed the abundance and diversity of gut microbiota using standard deviation means and random-effects models for different sampling methods and for ICU patients and healthy cohorts Results After entering the ICU for treatment, the intestinal flora of the patients and the normal population were significantly different, and the diversity and richness of the flora were significantly higher than those of the healthy population. In addition, using two different sampling methods, feces and swabs, had no significant effect on the α-diversity of intestinal flora in ICU patients. Conclusion Our results provide a comprehensive synthesis to better understand gut microbial perturbations associated between different sampling methods, as well as differences in the microbiota between ICU patients and healthy populations.