To preliminarily clarify the changes of intestinal microecological composition and diversity in patients with sepsis-induced myocardial dysfunction.

A total of 39 subjects were enrolled in this study, including 13 healthy subjects (group A), 12 septic patients without myocardial dysfunction (group B) and 14 patients with sepsis-induced myocardial dysfunction (group C). Blood and feces samples were collected and echocardiography was performed on the day of enrollment. The cardiac troponin T (cTnT), human heart-type fatty acid binding protein (HFABP), N-terminal pro-brain natriuretic peptide (NT-proBNP), left ventricular ejection fraction (LVEF) and procalcitonin (PCT) were determined and recorded. The 16S ribosomal DNA (rDNA) sequencing was used to determine the bacterial sequence in the feces, and the composition of microflora among the three groups was compared.

The levels of cTnT, HFABP, NT-proBNP, LVEF and PCT among the three groups all showed significant differences (H = 33.279, 24.748, 28.694, 26.552, 27.032; all P < 0.001). Further pairwise comparison found that compared with the group B, the levels of cTnT, HFABP and NT-proBNP in the group C were much higher, while the LVEF level was much lower (all P < 0.05). Alpha diversity analysis showed that the richness [Chao1 index and abundance-based coverage estimator (ACE)] and diversity (Shannon index and Simpson index) of bacterial flora among the three groups all showed significant differences (H = 13.761, 13.761, 19.189, 15.536; all P < 0.05). The richness and diversity of bacterial flora in groups B and C were much lower than those in the group A, and the diversity of bacterial flora in the group C was lowest (all P < 0.05). Beta diversity analysis showed that the similarities of bacterial flora among the three groups all showed significant differences [0.239 (0.147, 0.332), 0.001 (-0.164, 0.049), -0.212 (-0.315, 0.040); H = 22.599, P = 0.001]. The similarities of bacterial flora in groups B and C were statistically significantly different as compared with the group A (both P < 0.05). At the three levels of class, family and genus, the relative abundance of Clostridia, Bacillus, Ruminococcaceae, Lachnospiracea, Ruminococcus and Lachnospiracea_incertae_sedis among the three groups all showed significant differences (H = 23.918, 22.794, 17.265 16.846, 11.862, 16.846; all P < 0.05). The relative abundance of Clostridia, Ruminococcaceae, Lachnospiracea, Ruminococcus and Lachnospiracea_incertae_sedis in groups B and C was much lower than that in the group A, and the relative abundance of Clostridia, Ruminococcaceae and Lachnospiracea in the group C was lowest (all P < 0.05). The relative abundance of Bacillus in groups B and C was much higher than that in the group A, and it was highest in the group B (all P < 0.05).

The levels of myocardial injury biomarkers are increased and the diversity of intestinal microbiome is decreased significantly in patients with myocardial dysfunction induced by sepsis, which mainly shows as reduced abundance of Clostridia, Ruminococcaceae and Lachnospiracea, together with increased abundance of Bacillus.