A change in the gut microbiota composition in patients with chronic heart failure and small bacterial overgrowth syndrome

Abstract

A change in the gut microbiota composition is a risk factor for the development and progression of a number of socially significant diseases. Thus, the prevalence of small bacterial overgrowth syndrome (SBOS) in patients with chronic heart failure CHF) is 38.2–42.0%, as shown by different data, which greatly exceeds that among the persons without CHF. SBOS in CHF is associated with the higher risk of long-term complications (hospitalization and death). Objective. To study the qualitative changes in the large bowel gut microbiota in patients with CHF and SBOS. Subjects and methods. The investigation enrolled 60 patients with CHF and a left ventricular ejection fraction of <50%, as evidenced by echocardiography (after Simpton), who had undergone lactulose hydrogen breath test for the diagnosis of SBOS. According to the test results, the patients were divided into 2 groups; 1) 25 patients with SBOSs; 2) 25 patients without SBOS. In both groups, sequencing of 165 ribosomal RNA was used to study gut microbiota in the fecal samples. Results. Group 1 displayed a decrease in the Shannon index when calculated by bacterial types as compared with that in Group 2 (0.61 [0.49; 0.72] and 0.75 [0.58; 0.86], respectively; p=0.03). Group 1 also exhibited lower levels of the representatives of the Verrucomicrobia type as compared with Group 2 (0.21 [0.00; 4.03] and 2.61 [0.95; 8.02]%, respectively; p=0.05), in particular the Verrucomicrobiaceae family (0.21 [0.00; 4.03] and 2.61 [0.50; 8.42]%, respectively; p=0.05). The decreased level of the representatives of the Verrucomicrobiaceae family in patients with SBOS (Group 1) was due to the lower levels of the representatives of the Akkermansia genus (p=0.05), the only identified representative of which in this study was Akkermansia muciniphila; there were also decreased levels of the representatives of the Desulfovibrio genus (p=0.01), an increase in the representatives of the Dorea genus (p=0.005), as well as those presented in a small number of patients of Papillibacter (p = 0.02), Coprobacillus (p=0.02), Oribacterium (p=0,02), Clostridium cluster XVIII (p=0.05), Slackia genera (p=0.01). In addition, there were lower levels of the representatives of the the Dorea genus (p=0.005), as well as those presented in a small number of patients of Papillibacter (p = .0.02), Coprobacillus (p=0.02), Oribacterium (p=0,02), Clostridium cluster XVIII (p=0.05), Slackia genera (p=0.01).