重症肺炎患者肠道菌群变化及其与免疫 功能的关系.

Objective To study the changes in the intestinal flora of patients with severe pneumonia (SP) and to analyze their correlation with the body's immune function. Methods Sixteen cases of severe pneumonia were selected as the observation group, and 10 cases with healthy physical examination were selected as the control group. The fresh feces of the two groups were collected, and the intestinal microbiota abundance (Ace index, Chao index) and diversity (Simpson index, Shannon index) in the feces were analyzed by 16S rDNA gene sequencing technology, and the intestinal micro‐ biota abundances of the two groups at the phylum level and genus level were compared. The immunoglobulins (IgA, IgG, IgM), lymphocyte subsets (CD3+, CD4+, CD8+ T lymphocyte count and CD4+ /CD8+ ), white blood cell count (WBC), and neutrophil count (NEUT) were compared between the two groups. Results The Ace index, Chao index, Shannon index, CD3+, CD4+, CD8+ T lymphocyte counts, IgA and IgG were lower in the observation group than in the control group, and the Simpson index, WBC, NEUT and IgM were higher (all P<0. 05). The relative abundances of Firmicutes, Proteobacteria, Bifidobacterium, Escherichia coli, Ruminococcus species, Trichobacterium and Clostridium in the observation group were lower than those in the control group, and the relative abundances of Bacteroides, Actinomycetes, Enterococcus, Streptococcus and Klebsiella were higher than those in the control group (all P<0. 05). The relative abundance of Klebsiella in the intestinal flora of the observation group was positively correlated with CD3+ and CD8+ T lymphocyte counts, the relative abundances of Ruminococcus and Trichospirillum species were positively correlated with CD8+ T lymphocyte count, the relative abundance of Clostridium was positively correlated with IgM level, the relative abundance of Streptococcus was negatively correlated with IgM level, Escherichia coli and Klebsiella were negatively correlated with IgG levels, and Enterococcus species were negatively correlated with WBC (all P<0. 05). Conclusions The abundance and diversity of intestinal flora in patients with SP decrease significantly. The abundance of beneficial bacteria decreases and the abundance of conditional pathogenic bacteria increases. The changes in intestinal flora may indirectly participate in the development and progression of SP by affecting immune function. [ABSTRACT FROM AUTHOR]