AUTHOR=Szabó Bálint Gergely , Kiss Rebeka , Makra Nóra , Pénzes Kinga , Vad Eszter , Kamotsay Katalin , Szabó Dóra , Ostorházi Eszter 

TITLE=Composition and changes of blood microbiota in adult patients with community-acquired sepsis: A pilot study from bench to bedside

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.1067476

DOI=10.3389/fcimb.2022.1067476

ISSN=2235-2988

ABSTRACT=<sec><title>Background</title><p>Characteristics of the blood microbiota among adult patients with community-acquired sepsis are poorly understood. Our aim was to analyze the composition of blood microbiota in adult patients with community-acquired sepsis, and correlate changes with non-septic control patients.</p></sec><sec><title>Methods</title><p>A prospective observational study was carried out by including adult patients hospitalized for community-acquired sepsis at our center between January and November 2019, by random selection from a pool of eligible patients. Study inclusion was done on the day of sepsis diagnosis. Community acquisition was ascertained by <italic>a priori</italic> exclusion criteria; sepsis was defined according to the SEPSIS-3 definitions. Each included patient was matched with non-septic control patients by age and gender in a 1:1 fashion enrolled from the general population. Conventional culturing with BacT/ALERT system and 16S rRNA microbiota analysis were performed from blood samples taken in a same time from a patient. Abundance data was analyzed by the <italic>CosmosID HUB</italic> Microbiome software.</p></sec><sec><title>Results</title><p>Altogether, 13 hospitalized patients were included, 6/13 (46.2%) with sepsis and 7/13 (53.8%) with septic shock at diagnosis. The most prevalent etiopathogen isolated from blood cultures was <italic>Escherichia coli</italic>, patients mostly had intraabdominal septic source. At day 28, <italic>all-cause</italic> mortality was 15.4% (2/13). Compared to non-septic control patients, a relative scarcity of <italic>Faecalibacterium</italic>, <italic>Blautia, Coprococcus</italic> and <italic>Roseburia</italic> genera, with an abundance of <italic>Enhydrobacter</italic>, <italic>Pseudomonas</italic> and <italic>Micrococcus</italic> genera was observed among septic patients. Relative differences between septic vs. non-septic patients were more obvious at the phylum level, mainly driven by <italic>Firmicutes</italic> (25.7% vs. 63.1%; p&lt;0.01) and <italic>Proteobacteria</italic> (36.9% vs. 16.6%; p&lt;0.01). The alpha diversity, quantified by the <italic>Chao1</italic> index showed statistically significant difference between septic vs. non-septic patients (126 ± 51 vs. 66 ± 26; p&lt;0.01). The Bray-Curtis beta diversity, reported by principal coordinate analysis of total hit frequencies, revealed 2 potentially separate clusters among septic vs. non-septic patients.</p></sec><sec><title>Conclusion</title><p>In adult patients with community-acquired sepsis, specific changes in the composition and abundance of blood microbiota could be detected by 16S rRNA metagenome sequencing, compared to non-septic control patients. Traditional blood culture results only partially correlate with microbiota test results.</p></sec>