Analysis of fecal microbiota and related clinical indicators in ICU patients with sepsis

BackgroundTo analyze the characteristics of fecal microbiota disturbance in the intensive care unit (ICU) patients with sepsis and the correlation with related clinical indicators. MethodsThis study included 31 patients with sepsis admitted to the emergency ICU ward between September 2019 and December 2021. They were divided into Group without septic shock (NDNS group, 7 cases) and Group with septic shock (NDS group, 24 cases) according to the presence or absence of septic shock. Furthermore, we divided these 31 sepsis patients into Clinical Improvement group (21 cases) and Death or DAMA group (10 cases) based on clinical outcome, 15 cases of Physical Examiner recruited in the same period were included as control group: NDHC group (15 cases). The fecal samples of the patients with sepsis within 24 h of admission and random fecal samples of the control group were collected and analyzed by 16S rDNA gene sequencing used for the analysis of fecal microbiota. At the same time, the relevant clinical data of these patients with sepsis were also collected for analysis. ResultsThere were 15 cases with drug-resistant bacteria in the NDS group and only 2 cases in the NDNS group (P = 0. 015). There were significant differences in APACHE II score, length of ICU stay, lactate level, and oxygenation index of patients between the Death or DAMA group and Clinical Improvement group (all P < 0. 05). For phylum level, the abundance of Firmicutes, Actinobacteria, and Bacteroidetes decreased in the ND group compared with the NDHC group, while the abundance of Proteobacteria increased (P < 0. 05). For genus level, the relative abundance of Escherichia-Shigella and Klebsiella were significantly increased in the ND group compared with the NDHC group (P < 0. 05). The top six genera in relative abundance in the NDS group were Escherichia-Shigella, Enterococcus, Bifidobacterium, Lactobacillus, Akkermansia, and Klebsiella. Compared with the Clinical Improvement group, the relative abundance of Escherichia-Shigella and Klebsiella in the Death or DAMA group showed an increasing trend with no significant significance, while the relative abundance of Enterococcus and Faecalibacterium decreased in the Death or DAMA group (P < 0. 05). Alpha diversity analysis showed that compared with the NDHC group, the alpha diversity of the fecal microbiota in the ND group decreased. There were significant differences in the Observedₛpecies index, Chao1 index, and ACE index of patients between the NDHC group and ND group (all P < 0. 05). Moreover, compared with the NDNS group, the Alpha diversity of the NDS group was more abundant. PCoA analysis showed significant differences in microbial community structure between the ND group and NDHC group (P = 0. 001). There also were significant differences in microbial community structure between the NDS group and NDNS group (P = 0. 008). LEfSe analysis showed that compared with the NDHC group, there were significant differences in the species of the ND group, including Enterobacteriaceae, Escherichia-Shigella, Enterococcus, Elizabethkingia, and FamilyXIIIAD3011group. ConclusionsICU patients with sepsis suffered intestinal microecological disturbances with significantly decreased abundance of fecal microbiota, diversity, and beneficial symbiotic bacteria. For these patients, the ratio of pathogenic bacteria, including Escherichia-Shigella and Klebsiella increased and became the main bacterial genus in some samples. Moreover, the increasing trend of these two pathogenic bacteria may be correlated with the development of septic shock and the risk of death in patients with sepsis.