Microbial Community of Small Intestine in Acute Severe Pancreatitis Patients: a Pilot Study

Purpose of the study: to describe the composition of the microbiota of the initial sections of the small intestine in patients with severe necrotizing acute pancreatitis. Objectives of the study: 1. Determine the composition of the microbiota of the initial sections of the small intestine upon admission to the ICU; 2. Determine the differences in the composition of the microbiota of the initial sections of the small intestine, depending on the timing of the onset of the disease. Introduction. Disturbance of intestinal homeostasis is a leading factor in the pathogenesis and progression of systemic inflammation in patients with severe acute pancreatitis. The development of systemic complications occurs due to both mesenteric hypoperfusion and dysregulation of intestinal motility, and the destruction of the intestinal barrier, with the translocation of bacterial bodies and their substrates. Which increases the risk of developing POI and increasing mortality. With the advent of methods for high-throughput sequencing of microbiome samples - for example, in the 16S rRNA format - the possibilities for studying the structure of microbial communities have significantly expanded. In this regard, there is more and more evidence of the relationship between the state of human health and microflora inhabiting various parts of the body. Materials and methods. The study included 7 patients with a diagnosis of severe necrotizing acute pancreatitis (6 men, 1 woman), the mean age was 54.1 {+/-} 14.4 years. The patients were divided into two groups. Group 1 (n = 4) included patients admitted 2-4 days after the onset of a pain attack. Group 2 (n = 3) - patients admitted no later than 24 hours from the onset of the disease. The bacterial composition of jejunal wash samples was studied using 16S RNA sequencing. The severity of the condition was assessed using the integral scales APACHE II, SOFA, SAPS II. In patients of the main group, APACHE II was 22 {+/-} 2.83 points (18; 24), SOFA - 6.8 {+/-} 0.5 points (6; 7), SAPSII - 32.9 {+/-} 6.4 points (24.7; 40), in patients of the comparison group, APACHE II is 18.0 {+/-} 3.7 points (12; 22), SOFA - 4.0 {+/-} 2.6 points (2; 7), SAPSII - 24.4 {+/-} 5.0 points (20.9; 30.1). Material was collected at the time of installation of a sterile multifunctional intestinal catheter for Treitz's ligament, no later than 12 hours from the moment of admission to the ICU. At the time of sampling, patients were not receiving antibiotic therapy. Results. A more severe course was associated with a reduced representation in the microbiome of the species Nesseria mucosa and Parvimonas micra inhabiting the mucosal layer, as well as Megasphaera micronuciformis. The share of Streptococcus genera (S. rubneri / parasanguinis / australis species) and Actinomyces and a number of genera from the Enterobacteriaceae family in such patients, on the contrary, was higher.